66
DCTC 2018 QUINTA EDIZIONE Quinto Congresso della Divisione di Chimica Teorica e Computazionale della Società Chimica Italiana Università degli Studi di Trieste, 19 - 21 settembre 2018 aula 1A, Edificio H3, Via Alfonso Valerio 12/2. [email protected] Comitato scientifico: Vincenzo Barone Carlo Adamo Benedetta Mennucci Maria Cristina Menziani Michele Pavone Nino Polimeno Cristina Puzzarini Emilia Sicilia Mauro Stener Comitato organizzatore locale: Mauro Stener Giovanna Fronzoni Daniele Toffoli

DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

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Page 1: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

DCTC 2018 QUINTA EDIZIONE

Quinto Congresso della Divisione di Chimica Teorica e Computazionale

della Societagrave Chimica Italiana

Universitagrave degli Studi di Trieste 19 - 21 settembre 2018

aula 1A Edificio H3 Via Alfonso Valerio 122

dctc18unitsit

Comitato scientifico

Vincenzo Barone

Carlo Adamo

Benedetta Mennucci

Maria Cristina Menziani

Michele Pavone

Nino Polimeno

Cristina Puzzarini

Emilia Sicilia

Mauro Stener

Comitato organizzatore locale

Mauro Stener

Giovanna Fronzoni

Daniele Toffoli

PROGRAMMA

Mercoledigrave 19 Settembre 1445-1500 Apertura del congresso

Sessione 1 Chairman Maria Cristina Menziani

1500-1545 Invited ndash Piero Decleva

Solving the Schroumldinger equation in a box wavepackets and continuum states

1545-1600 Sofia Canola ldquoVibrational and optical fingerprints of conjugated

biradicals from DFT and TDDFT calculationsrdquo

1600-1615 Marco Mendolicchio ldquoNew computational strategies for the calculation of

anharmonic force fieldsrdquo

1615-1630 Loredana Edith Daga ldquoOn Optimizing Gaussian Basis sets for Crystalline Solidsrdquo

1630-1700 Coffee Break (Atrio edificio H3)

Sessione 2 Chairman Benedetta Mennucci

1700-1745 Invited ndashFabrizio Santoro

Mixed quantumclassical description of the effects of nuclear motion in electronic

spectroscopy and ultrafast photophysics

1745-1800 Emanuele Coccia ldquoWave function-based approach to probe coherence in ultrafast

molecular processesrdquo

1800-1815 Amalia Velardo ldquoBand Shapes of Singlet-Triplet Transitionsrdquo

1815-1830 Laura Zanetti Polzi ldquoModeling amide I infrared spectra of proteins insights from

a perturbative approachrdquo

Giovedigrave 20 Settembre Sessione 3 Chairman Carlo Adamo

915-1000 Invited ndash Ana B Muntildeoz Garciacutea

Defective but effective the role of defects on the electrocatalytic performance of

oxide-based materials for energy conversion

1000-1015 Mario Prejanograve ldquoThe effect of distortions of a covalent enzymatic intermediate in

Human Transketolase a computational point of viewrdquo

1015-1030 Francesco Sessa ldquoLa3+

ion in EAN aqueous mixtures a MD-XAS investigation on

the effect of water concentrationrdquo

1030-1045 Diego Cesario ldquoSource of Cooperativity in Hydrogen-Bonded Supramolecular

Polymersrdquo

1045-1130 Coffee Break (Terrazza aula 1B primo piano edificio H3)

Sessione 4 Chairman Nino Polimeno

1130-1215 Invited ndashAnna Painelli

Solvent dynamics and energy transfer a real time description

1215-1230 Gloria Mazzone ldquoAiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum Mechanic approachesrdquo

1230-1245 Michele Guerrini ldquoSolid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulationsrdquo

1245-1300 Mirco Zerbetto ldquoPrevisione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studiordquo

1300-1530 Pranzo + Poster session (Atrio edificio H3)

Sessione 5 Chairman Cristina Puzzarini

1530-1545 Francesco Faglioni ldquoSelf interaction charge delocalization electrolyte

ionizationrdquo

1545-1600 Mattia Anzola ldquoOptical spectra of molecular aggregates testing approximation

schemesrdquo

1600-1615 Martina De Vetta ldquoSimulations of a liposomal assisted delivery of the Temoporfin

photosensitizerrdquo

1615-1630 Matteo Masetti ldquoThe best of both worlds combining Markov State Models and

Path Collective Variables to describe protein-ligand bindingrdquo

1630-1645 Ida Ritacco ldquoThe mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic level multiscale

simulationsrdquo

1645-1700 Tommaso Giovannini ldquoDevelopment of Theoretical Approaches to Model the

Spectral Properties of Complex Systemsrdquo

1700-1745 Invited ndash Marco Garavelli

Towards an accurate computational photochemistry and photobiology the

paradigmatic case of vision

1745-1900 Assemblea della Divisione di Chimica Teorica e Computazionale della SCI

Venerdigrave 21 Settembre Sessione 6 Chairman Emilia Sicilia

915-1000 Invited ndash Gianni Cardini

Modellizzazione in fase condensata ad alte pressioni

1000-1015 Fortuna Ponte ldquoComputational investigation of the platinum(IV) anticancer

prodrugs reduction mechanism by L-ascorbic acidrdquo

1015-1030 Laura Falivene ldquoTuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behaviorrdquo

1030-1045 Eduardo Schiavo ldquoInvestigating photoelectrochemical properties of dye-electrode

interfaces with density functional embedding theoryrdquo

1045-1100 Tainah Dorina Marforio ldquoCarbon nanotubes (CNTS) as nano-reactors

regioselectivity and kinetics control for the bromination of N-phenylacetamide A

QMMM investigationrdquo

1100-1145 Coffee Break (Atrio edificio H3)

Sessione 7 Sessione premi e medaglie Nordio ndash del Re ndash Scrocco ndash Roetti

Chairman Vincenzo Barone

1145-1200 Premio del Re Francesco Avanzini ldquoThe Quantum Molecular Trajectoryrdquo

1200-1230 Premio Scrocco Francesco Muniz-Miranda

Studies on the optoelectronic properties of metal nanoclusters and complexes

1230-1300 Premio Roetti Lorenzo Maschio

Quantum chemistry of crystalline solids using a local basis set the CRYSTAL

and CRYSCOR codes

1300 Conclusioni

Conferenze su invito Nome DipartimentoIstituzione Titolo contributo n

Piero Decleva DSCF Universitagrave di Trieste

Solving the Schroumldinger equation in a box wavepackets

and continuum states

I1

Fabrizio Santoro

ICCOM-CNR Area della Ricerca

del CNR di Pisa

Mixed quantumclassical description of the effects of

nuclear motion in electronic spectroscopy and ultrafast

photophysics

I2

Ana B Muntildeoz

Garciacutea

Dipartimento di Fisica ldquoEttore

Pancinirdquo Universitagrave di Napoli

Federico II

Defective but effective the role of defects on the

electrocatalytic performance of oxide-based materials for

energy conversion

I3

Anna Painelli

Dipartimento SCVSA Universitagrave

di Parma

Solvent dynamics and energy transfer

a real time description

I4

Marco Garavelli

Dipartimento di Chimica

Industriale ldquoToso Montanarirdquo

Bologna

Towards an accurate computational photochemistry and

photobiology the paradigmatic case of vision

I5

Gianni Cardini

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave di Firenze

Modellizzazione in fase condensata ad alte pressioni I6

Premi

Nome DipartimentoIstituzione Titolo contributo premio

Lorenzo Maschio Dipartimento di Chimica

Universitagrave di Torino

Quantum chemistry of crystalline solids using a local

basis set the CRYSTAL and CRYSCOR codes

Roetti

Francesco Muniz-

Miranda

Gent Universiteit Belgieuml Studies on the optoelectronic properties of metal

nanoclusters and complexes

Scrocco

Francesco Avanzini Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova

The Quantum Molecular Trajectory del Re

Contributi Orali

Nome DipartimentoIstituzione Titolo contributo n

Sofia Canola

Dipartimento di Chimica ldquoG

Ciamicianrdquo University of

Bologna via F Selmi 2 Bologna

Italy

Vibrational and optical fingerprints of conjugated

biradicals from DFT and TDDFT calculations

O1

Marco

Mendolicchio

Scuola Normale Superiore I-

56126 Pisa Italy

New computational strategies for the calculation of

anharmonic force fields

O2

Loredana Edith

Daga

Diparimento di Chimica

Universitagrave di Torino

On Optimizing Gaussian Basis sets for Crystalline Solids O3

Emanuele Coccia

Dipartimento di Scienze

Chimiche Universitagrave di Padova

via Marzolo 1 Padova Italy

Wave function-based approach to probe coherence in

ultrafast molecular processes

O4

Amalia Velardo

Dipartimento Chimica e Biologia

ldquoAdolfo Zambellirdquo Universitagrave

degli Studi di Salerno Via G

Paolo II 84084-Fisciano Italy

Band Shapes of Singlet-Triplet Transitions

O5

Laura Zanetti-Polzi

Department of Physical and

Chemical Sciences University of

LAquila Via Vetoio (Coppito1)

67010 LAquila Italy

Modeling amide I infrared spectra of proteins insights

from a perturbative approach

O6

Mario Prejanograve

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende (CS) Italia

The effect of distortions of a covalent enzymatic

intermediate in Human Transketolase a computational

point of view

O7

F Sessa

Department of Chemistry

University of Rome ldquoLa

Sapienzardquo Rome Italy

La3+ ion in EAN aqueous mixtures a MD-XAS

investigation on the effect of water concentration

O8

Diego Cesario

- Department of Chemistry and

Pharmaceutical Sciences and

Amsterdam Center for Multiscale

Modeling Vrije Universiteit

Amsterdam De Boelelaan 1083

1081 HV Amsterdam The

Netherlands

- Department of Chemistry

Biology and Biotechnology

University of Perugia

via Elce di Sotto 8 I-06123

Perugia Italy

Source of Cooperativity in Hydrogen-Bonded

Supramolecular Polymers

O9

Gloria Mazzone Chimie ParisTech PSL Research

University CNRS Institut de

Recherche de Chimie Paris Paris

France

Aiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

O10

Michele Guerrini

Dipartimento FIM Universitagrave di

Modena e Reggio Emilia Italy

Solid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulations

O11

Mirco Zerbetto

Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova Padova 35313 Italia

Previsione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studio

O12

F Faglioni

DSCG Univ of Modena and

Reggio Emilia Modena Italy

Self interaction charge delocalization electrolyte

ionization

O13

Mattia Anzola

Dipartimento di Scienze

Chimiche della Vita e della

Sostenibilitagrave Ambientale

Universitagrave degli Studi di Parma

Italy

Optical spectra of molecular aggregates testing

approximation schemes

O14

Martina De Vetta

-Institute of Theoretical

Chemistry Faculty of Chemistry

University of Vienna Waumlhringer

Str 17 A-1090 Vienna Austria

-Departamento de u mica

Universidad Aut noma de Madrid

Francisco Tomaacutes y Valiente 7

28049 Cantoblanco Madrid Spain

Simulations of a liposomal assisted delivery of the

Temoporfin photosensitizer

O15

Matteo Masetti Department of Pharmacy and

Biotechnology (FaBiT) Alma

Mater Studiorum ndash University of

Bologna Italy

The best of both worlds combining Markov State Models

and Path Collective Variables to describe protein-ligand

binding

O16

Ida Ritacco

CNR-IOM co SISSA via

Bonomea 265 34136 Trieste Italy

The mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic

level multiscale simulations

O17

Tommaso

Giovannini

Scuola Normale Superiore Piazza

dei Cavalieri 7 Pisa IT

Development of Theoretical Approaches to Model the

Spectral Properties of Complex Systems

O18

Fortuna Ponte

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria

Computational investigation of the platinum(IV)

anticancer prodrugs reduction mechanism by L-ascorbic

acid

O19

Laura Falivene

KAUST Catalysis Center King

Abdullah University of Science

and Technology Thuwal 23955-

6900 Saudi Arabia

Tuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behavior

O20

E Schiavo

Department of Chemical Sciences

University of Naples Federico II

Comp Univ Monte SantrsquoAngelo

Via Cintia 21 80126 Naples Italy

Investigating photoelectrochemical properties of dye-

electrode interfaces with density functional embedding

theory

O21

Tainah Dorina

Marforio

Dipartimento di Chimica ldquoG

Ciamicianrdquo Alma Mater

Studiorum ndash Universitagrave di

Bologna via Selmi 2 40126

Bologna

Italy

CARBON NANOTUBES (CNTS) AS NANO-

REACTORS

REGIOSELECTIVITY AND KINETICS CONTROL

FOR

THE BROMINATION OF N-PHENYLACETAMIDE

A QMMM INVESTIGATION

O22

Poster Nome DipartimentoIstituzione Titolo contributo n

F Cappelluti

Universitagrave degli Studi dellrsquoAquila

- LrsquoAquila

F-RESP a fast and accurate polarizable force field P1

Francesco Tavanti

Department of Chemical and

Geological Sciences University of

Modena and Reggio Emilia Via

Campi 103 41125

Modena Italy

Natural compounds for Alzheimerrsquos disease treatment a

classical

Molecular Dynamics investigation

P2

E Bernes

Department of Chemical and

Pharmaceutical Sciences

University of Trieste 34127

Trieste Italy

Core-Electron Excitations in Dibenzothiophene

Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

P3

Baiano C

Department of Chemical Sciences

University of Naples Federico II

Ab initio characterization of CO2 photoreduction

mechanism at CuFeO2 delafossite electrode

P4

Davide Accomasso

Department of Chemistry and

Industrial Chemistry University

of Pisa Italy

Seeking new materials for singlet fission

covalent dimers as an alternative to molecular crystals

P5

Henry Adenusi

Chemistry Department University

of Rome ldquoLa Sapienzardquo Italy

Proton transfer mechanisms in protic ionic liquids P6

Giorgia Beata

Dipartimento di Chimica

Universitagrave di Torino Via Giuria 7

I-10125 Torino Italy

CRYSPLOT a new tool to visualize physical and

chemical properties of crystalline solids

P7

Marco Pagliai

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze via della Lastruccia 3

50019 Sesto Fiorentino (FI) Italy

Molecular dynamics simulations of zinc proteins a

new force field

P8

Eslam M Moustafa

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria I-87036 Aracavacta

di Rende (CS) Italy

Reduction of Pt(IV) anticancer drugs a DFT mechanistic

study

P9

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Rapid evaluation of dynamic disorder in organic

semiconductors

P10

Isabella Romeo

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P11

Marina

Macchiagodena

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze Via della Lastruccia 3 I-

50019 Sesto Fiorentino Italy

Improved force fields for molecular dynamics

simulations of zinc proteins

P12

Marco Fusegrave

Scuola Normale Superiore Piazza

dei Cavalieri 7 56126 Pisa Italy

Computational simulation of vibrationally resolved

spectra for spin‐forbidden transitionsforbidden transitions

P13

Tiziana Marino

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P14

Matteo Capone

Universitagrave dellrsquoAquila Italia Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

P15

J FREGONI

Dipartimento di scienze Fisiche

Informatiche e Matematiche

University of Modena and Reggio

Emilia I-41125 Modena Italy

Manipulating azobenzene photoisomerization

through strong light-molecule coupling

P16

Irene Conti

Dipartimento di Chimica

Industriale ldquo Toso Montanarirdquo

Universita  di Bologna Viale del

Risorgimento 4 I-40136 Bologna

Italy

Excitonic State evolution of DNA Stacked Thymines

Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

P17

Andrea Le Donne

Chemistry department University

of Rome ldquoLa Sapienzardquo Rome

Italy

Ionic Liquids and Proton Transfer A Computational

Study to Understand Dynamic Processes

P18

Franco Egidi

Scuola Normale Superiore 56126

Pisa Italy

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

P19

Arianna Massaro

Department of Chemical Science

University of Naples ldquoFederico

IIrdquo via Cintia 21 80126 Naples

Italy

Unveiling the role of structural features in Na insertion

mechanism at anatase surfaces new insights for Na-ion

batteries development

P20

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Hole Mobility in Organic Semiconductors A Second-

Order Cumulant Approach

P21

Mariagrazia Fortino

Universitagrave di Modena e Reggio

Emilia Modena 41125 Italy

On the Simulation of Vibrationally Resolved Electronic

Spectra of medium-size molecules the case of Styryl

Substituted BODIPYs

P22

Marco Medves Dipdi Scienze Chimiche e

Farmaceutiche Universitagrave di

Trieste

Theoretical Study on the Circular Dichroism of Chiral

Bimetallic Clusters Ag-Au

P23

Jonathan Campeggio

Universitagrave degli Studi di Padova DiTe2 Calcolo del tensore di diffusione per molecole

flessibili

P24

Edoardo Jun

Mattioli

Chemistry Department ldquoG

Ciamicianrdquo University of Bologna

Computational Investigation of Competitive

Reaction Mechanisms inside Carbon Nanotubes

P25

Sergio Rampino

SMART Laboratory Scuola

Normale Superiore Piazza dei

Cavalieri 7 56126 Pisa

Combined Orbital-spaceReal-space Analysis of

Chemical Bonding through Virtual Reality

P26

Josephine Alba Dipdi Chimica Universitagrave di

Roma La Sapienza

Efficient and Accurate Modelling of Conformational

Transitions in proteins comparison between two Src

kinase proteins

P27

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 2: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

PROGRAMMA

Mercoledigrave 19 Settembre 1445-1500 Apertura del congresso

Sessione 1 Chairman Maria Cristina Menziani

1500-1545 Invited ndash Piero Decleva

Solving the Schroumldinger equation in a box wavepackets and continuum states

1545-1600 Sofia Canola ldquoVibrational and optical fingerprints of conjugated

biradicals from DFT and TDDFT calculationsrdquo

1600-1615 Marco Mendolicchio ldquoNew computational strategies for the calculation of

anharmonic force fieldsrdquo

1615-1630 Loredana Edith Daga ldquoOn Optimizing Gaussian Basis sets for Crystalline Solidsrdquo

1630-1700 Coffee Break (Atrio edificio H3)

Sessione 2 Chairman Benedetta Mennucci

1700-1745 Invited ndashFabrizio Santoro

Mixed quantumclassical description of the effects of nuclear motion in electronic

spectroscopy and ultrafast photophysics

1745-1800 Emanuele Coccia ldquoWave function-based approach to probe coherence in ultrafast

molecular processesrdquo

1800-1815 Amalia Velardo ldquoBand Shapes of Singlet-Triplet Transitionsrdquo

1815-1830 Laura Zanetti Polzi ldquoModeling amide I infrared spectra of proteins insights from

a perturbative approachrdquo

Giovedigrave 20 Settembre Sessione 3 Chairman Carlo Adamo

915-1000 Invited ndash Ana B Muntildeoz Garciacutea

Defective but effective the role of defects on the electrocatalytic performance of

oxide-based materials for energy conversion

1000-1015 Mario Prejanograve ldquoThe effect of distortions of a covalent enzymatic intermediate in

Human Transketolase a computational point of viewrdquo

1015-1030 Francesco Sessa ldquoLa3+

ion in EAN aqueous mixtures a MD-XAS investigation on

the effect of water concentrationrdquo

1030-1045 Diego Cesario ldquoSource of Cooperativity in Hydrogen-Bonded Supramolecular

Polymersrdquo

1045-1130 Coffee Break (Terrazza aula 1B primo piano edificio H3)

Sessione 4 Chairman Nino Polimeno

1130-1215 Invited ndashAnna Painelli

Solvent dynamics and energy transfer a real time description

1215-1230 Gloria Mazzone ldquoAiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum Mechanic approachesrdquo

1230-1245 Michele Guerrini ldquoSolid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulationsrdquo

1245-1300 Mirco Zerbetto ldquoPrevisione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studiordquo

1300-1530 Pranzo + Poster session (Atrio edificio H3)

Sessione 5 Chairman Cristina Puzzarini

1530-1545 Francesco Faglioni ldquoSelf interaction charge delocalization electrolyte

ionizationrdquo

1545-1600 Mattia Anzola ldquoOptical spectra of molecular aggregates testing approximation

schemesrdquo

1600-1615 Martina De Vetta ldquoSimulations of a liposomal assisted delivery of the Temoporfin

photosensitizerrdquo

1615-1630 Matteo Masetti ldquoThe best of both worlds combining Markov State Models and

Path Collective Variables to describe protein-ligand bindingrdquo

1630-1645 Ida Ritacco ldquoThe mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic level multiscale

simulationsrdquo

1645-1700 Tommaso Giovannini ldquoDevelopment of Theoretical Approaches to Model the

Spectral Properties of Complex Systemsrdquo

1700-1745 Invited ndash Marco Garavelli

Towards an accurate computational photochemistry and photobiology the

paradigmatic case of vision

1745-1900 Assemblea della Divisione di Chimica Teorica e Computazionale della SCI

Venerdigrave 21 Settembre Sessione 6 Chairman Emilia Sicilia

915-1000 Invited ndash Gianni Cardini

Modellizzazione in fase condensata ad alte pressioni

1000-1015 Fortuna Ponte ldquoComputational investigation of the platinum(IV) anticancer

prodrugs reduction mechanism by L-ascorbic acidrdquo

1015-1030 Laura Falivene ldquoTuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behaviorrdquo

1030-1045 Eduardo Schiavo ldquoInvestigating photoelectrochemical properties of dye-electrode

interfaces with density functional embedding theoryrdquo

1045-1100 Tainah Dorina Marforio ldquoCarbon nanotubes (CNTS) as nano-reactors

regioselectivity and kinetics control for the bromination of N-phenylacetamide A

QMMM investigationrdquo

1100-1145 Coffee Break (Atrio edificio H3)

Sessione 7 Sessione premi e medaglie Nordio ndash del Re ndash Scrocco ndash Roetti

Chairman Vincenzo Barone

1145-1200 Premio del Re Francesco Avanzini ldquoThe Quantum Molecular Trajectoryrdquo

1200-1230 Premio Scrocco Francesco Muniz-Miranda

Studies on the optoelectronic properties of metal nanoclusters and complexes

1230-1300 Premio Roetti Lorenzo Maschio

Quantum chemistry of crystalline solids using a local basis set the CRYSTAL

and CRYSCOR codes

1300 Conclusioni

Conferenze su invito Nome DipartimentoIstituzione Titolo contributo n

Piero Decleva DSCF Universitagrave di Trieste

Solving the Schroumldinger equation in a box wavepackets

and continuum states

I1

Fabrizio Santoro

ICCOM-CNR Area della Ricerca

del CNR di Pisa

Mixed quantumclassical description of the effects of

nuclear motion in electronic spectroscopy and ultrafast

photophysics

I2

Ana B Muntildeoz

Garciacutea

Dipartimento di Fisica ldquoEttore

Pancinirdquo Universitagrave di Napoli

Federico II

Defective but effective the role of defects on the

electrocatalytic performance of oxide-based materials for

energy conversion

I3

Anna Painelli

Dipartimento SCVSA Universitagrave

di Parma

Solvent dynamics and energy transfer

a real time description

I4

Marco Garavelli

Dipartimento di Chimica

Industriale ldquoToso Montanarirdquo

Bologna

Towards an accurate computational photochemistry and

photobiology the paradigmatic case of vision

I5

Gianni Cardini

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave di Firenze

Modellizzazione in fase condensata ad alte pressioni I6

Premi

Nome DipartimentoIstituzione Titolo contributo premio

Lorenzo Maschio Dipartimento di Chimica

Universitagrave di Torino

Quantum chemistry of crystalline solids using a local

basis set the CRYSTAL and CRYSCOR codes

Roetti

Francesco Muniz-

Miranda

Gent Universiteit Belgieuml Studies on the optoelectronic properties of metal

nanoclusters and complexes

Scrocco

Francesco Avanzini Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova

The Quantum Molecular Trajectory del Re

Contributi Orali

Nome DipartimentoIstituzione Titolo contributo n

Sofia Canola

Dipartimento di Chimica ldquoG

Ciamicianrdquo University of

Bologna via F Selmi 2 Bologna

Italy

Vibrational and optical fingerprints of conjugated

biradicals from DFT and TDDFT calculations

O1

Marco

Mendolicchio

Scuola Normale Superiore I-

56126 Pisa Italy

New computational strategies for the calculation of

anharmonic force fields

O2

Loredana Edith

Daga

Diparimento di Chimica

Universitagrave di Torino

On Optimizing Gaussian Basis sets for Crystalline Solids O3

Emanuele Coccia

Dipartimento di Scienze

Chimiche Universitagrave di Padova

via Marzolo 1 Padova Italy

Wave function-based approach to probe coherence in

ultrafast molecular processes

O4

Amalia Velardo

Dipartimento Chimica e Biologia

ldquoAdolfo Zambellirdquo Universitagrave

degli Studi di Salerno Via G

Paolo II 84084-Fisciano Italy

Band Shapes of Singlet-Triplet Transitions

O5

Laura Zanetti-Polzi

Department of Physical and

Chemical Sciences University of

LAquila Via Vetoio (Coppito1)

67010 LAquila Italy

Modeling amide I infrared spectra of proteins insights

from a perturbative approach

O6

Mario Prejanograve

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende (CS) Italia

The effect of distortions of a covalent enzymatic

intermediate in Human Transketolase a computational

point of view

O7

F Sessa

Department of Chemistry

University of Rome ldquoLa

Sapienzardquo Rome Italy

La3+ ion in EAN aqueous mixtures a MD-XAS

investigation on the effect of water concentration

O8

Diego Cesario

- Department of Chemistry and

Pharmaceutical Sciences and

Amsterdam Center for Multiscale

Modeling Vrije Universiteit

Amsterdam De Boelelaan 1083

1081 HV Amsterdam The

Netherlands

- Department of Chemistry

Biology and Biotechnology

University of Perugia

via Elce di Sotto 8 I-06123

Perugia Italy

Source of Cooperativity in Hydrogen-Bonded

Supramolecular Polymers

O9

Gloria Mazzone Chimie ParisTech PSL Research

University CNRS Institut de

Recherche de Chimie Paris Paris

France

Aiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

O10

Michele Guerrini

Dipartimento FIM Universitagrave di

Modena e Reggio Emilia Italy

Solid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulations

O11

Mirco Zerbetto

Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova Padova 35313 Italia

Previsione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studio

O12

F Faglioni

DSCG Univ of Modena and

Reggio Emilia Modena Italy

Self interaction charge delocalization electrolyte

ionization

O13

Mattia Anzola

Dipartimento di Scienze

Chimiche della Vita e della

Sostenibilitagrave Ambientale

Universitagrave degli Studi di Parma

Italy

Optical spectra of molecular aggregates testing

approximation schemes

O14

Martina De Vetta

-Institute of Theoretical

Chemistry Faculty of Chemistry

University of Vienna Waumlhringer

Str 17 A-1090 Vienna Austria

-Departamento de u mica

Universidad Aut noma de Madrid

Francisco Tomaacutes y Valiente 7

28049 Cantoblanco Madrid Spain

Simulations of a liposomal assisted delivery of the

Temoporfin photosensitizer

O15

Matteo Masetti Department of Pharmacy and

Biotechnology (FaBiT) Alma

Mater Studiorum ndash University of

Bologna Italy

The best of both worlds combining Markov State Models

and Path Collective Variables to describe protein-ligand

binding

O16

Ida Ritacco

CNR-IOM co SISSA via

Bonomea 265 34136 Trieste Italy

The mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic

level multiscale simulations

O17

Tommaso

Giovannini

Scuola Normale Superiore Piazza

dei Cavalieri 7 Pisa IT

Development of Theoretical Approaches to Model the

Spectral Properties of Complex Systems

O18

Fortuna Ponte

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria

Computational investigation of the platinum(IV)

anticancer prodrugs reduction mechanism by L-ascorbic

acid

O19

Laura Falivene

KAUST Catalysis Center King

Abdullah University of Science

and Technology Thuwal 23955-

6900 Saudi Arabia

Tuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behavior

O20

E Schiavo

Department of Chemical Sciences

University of Naples Federico II

Comp Univ Monte SantrsquoAngelo

Via Cintia 21 80126 Naples Italy

Investigating photoelectrochemical properties of dye-

electrode interfaces with density functional embedding

theory

O21

Tainah Dorina

Marforio

Dipartimento di Chimica ldquoG

Ciamicianrdquo Alma Mater

Studiorum ndash Universitagrave di

Bologna via Selmi 2 40126

Bologna

Italy

CARBON NANOTUBES (CNTS) AS NANO-

REACTORS

REGIOSELECTIVITY AND KINETICS CONTROL

FOR

THE BROMINATION OF N-PHENYLACETAMIDE

A QMMM INVESTIGATION

O22

Poster Nome DipartimentoIstituzione Titolo contributo n

F Cappelluti

Universitagrave degli Studi dellrsquoAquila

- LrsquoAquila

F-RESP a fast and accurate polarizable force field P1

Francesco Tavanti

Department of Chemical and

Geological Sciences University of

Modena and Reggio Emilia Via

Campi 103 41125

Modena Italy

Natural compounds for Alzheimerrsquos disease treatment a

classical

Molecular Dynamics investigation

P2

E Bernes

Department of Chemical and

Pharmaceutical Sciences

University of Trieste 34127

Trieste Italy

Core-Electron Excitations in Dibenzothiophene

Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

P3

Baiano C

Department of Chemical Sciences

University of Naples Federico II

Ab initio characterization of CO2 photoreduction

mechanism at CuFeO2 delafossite electrode

P4

Davide Accomasso

Department of Chemistry and

Industrial Chemistry University

of Pisa Italy

Seeking new materials for singlet fission

covalent dimers as an alternative to molecular crystals

P5

Henry Adenusi

Chemistry Department University

of Rome ldquoLa Sapienzardquo Italy

Proton transfer mechanisms in protic ionic liquids P6

Giorgia Beata

Dipartimento di Chimica

Universitagrave di Torino Via Giuria 7

I-10125 Torino Italy

CRYSPLOT a new tool to visualize physical and

chemical properties of crystalline solids

P7

Marco Pagliai

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze via della Lastruccia 3

50019 Sesto Fiorentino (FI) Italy

Molecular dynamics simulations of zinc proteins a

new force field

P8

Eslam M Moustafa

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria I-87036 Aracavacta

di Rende (CS) Italy

Reduction of Pt(IV) anticancer drugs a DFT mechanistic

study

P9

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Rapid evaluation of dynamic disorder in organic

semiconductors

P10

Isabella Romeo

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P11

Marina

Macchiagodena

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze Via della Lastruccia 3 I-

50019 Sesto Fiorentino Italy

Improved force fields for molecular dynamics

simulations of zinc proteins

P12

Marco Fusegrave

Scuola Normale Superiore Piazza

dei Cavalieri 7 56126 Pisa Italy

Computational simulation of vibrationally resolved

spectra for spin‐forbidden transitionsforbidden transitions

P13

Tiziana Marino

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P14

Matteo Capone

Universitagrave dellrsquoAquila Italia Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

P15

J FREGONI

Dipartimento di scienze Fisiche

Informatiche e Matematiche

University of Modena and Reggio

Emilia I-41125 Modena Italy

Manipulating azobenzene photoisomerization

through strong light-molecule coupling

P16

Irene Conti

Dipartimento di Chimica

Industriale ldquo Toso Montanarirdquo

Universita  di Bologna Viale del

Risorgimento 4 I-40136 Bologna

Italy

Excitonic State evolution of DNA Stacked Thymines

Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

P17

Andrea Le Donne

Chemistry department University

of Rome ldquoLa Sapienzardquo Rome

Italy

Ionic Liquids and Proton Transfer A Computational

Study to Understand Dynamic Processes

P18

Franco Egidi

Scuola Normale Superiore 56126

Pisa Italy

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

P19

Arianna Massaro

Department of Chemical Science

University of Naples ldquoFederico

IIrdquo via Cintia 21 80126 Naples

Italy

Unveiling the role of structural features in Na insertion

mechanism at anatase surfaces new insights for Na-ion

batteries development

P20

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Hole Mobility in Organic Semiconductors A Second-

Order Cumulant Approach

P21

Mariagrazia Fortino

Universitagrave di Modena e Reggio

Emilia Modena 41125 Italy

On the Simulation of Vibrationally Resolved Electronic

Spectra of medium-size molecules the case of Styryl

Substituted BODIPYs

P22

Marco Medves Dipdi Scienze Chimiche e

Farmaceutiche Universitagrave di

Trieste

Theoretical Study on the Circular Dichroism of Chiral

Bimetallic Clusters Ag-Au

P23

Jonathan Campeggio

Universitagrave degli Studi di Padova DiTe2 Calcolo del tensore di diffusione per molecole

flessibili

P24

Edoardo Jun

Mattioli

Chemistry Department ldquoG

Ciamicianrdquo University of Bologna

Computational Investigation of Competitive

Reaction Mechanisms inside Carbon Nanotubes

P25

Sergio Rampino

SMART Laboratory Scuola

Normale Superiore Piazza dei

Cavalieri 7 56126 Pisa

Combined Orbital-spaceReal-space Analysis of

Chemical Bonding through Virtual Reality

P26

Josephine Alba Dipdi Chimica Universitagrave di

Roma La Sapienza

Efficient and Accurate Modelling of Conformational

Transitions in proteins comparison between two Src

kinase proteins

P27

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 3: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Giovedigrave 20 Settembre Sessione 3 Chairman Carlo Adamo

915-1000 Invited ndash Ana B Muntildeoz Garciacutea

Defective but effective the role of defects on the electrocatalytic performance of

oxide-based materials for energy conversion

1000-1015 Mario Prejanograve ldquoThe effect of distortions of a covalent enzymatic intermediate in

Human Transketolase a computational point of viewrdquo

1015-1030 Francesco Sessa ldquoLa3+

ion in EAN aqueous mixtures a MD-XAS investigation on

the effect of water concentrationrdquo

1030-1045 Diego Cesario ldquoSource of Cooperativity in Hydrogen-Bonded Supramolecular

Polymersrdquo

1045-1130 Coffee Break (Terrazza aula 1B primo piano edificio H3)

Sessione 4 Chairman Nino Polimeno

1130-1215 Invited ndashAnna Painelli

Solvent dynamics and energy transfer a real time description

1215-1230 Gloria Mazzone ldquoAiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum Mechanic approachesrdquo

1230-1245 Michele Guerrini ldquoSolid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulationsrdquo

1245-1300 Mirco Zerbetto ldquoPrevisione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studiordquo

1300-1530 Pranzo + Poster session (Atrio edificio H3)

Sessione 5 Chairman Cristina Puzzarini

1530-1545 Francesco Faglioni ldquoSelf interaction charge delocalization electrolyte

ionizationrdquo

1545-1600 Mattia Anzola ldquoOptical spectra of molecular aggregates testing approximation

schemesrdquo

1600-1615 Martina De Vetta ldquoSimulations of a liposomal assisted delivery of the Temoporfin

photosensitizerrdquo

1615-1630 Matteo Masetti ldquoThe best of both worlds combining Markov State Models and

Path Collective Variables to describe protein-ligand bindingrdquo

1630-1645 Ida Ritacco ldquoThe mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic level multiscale

simulationsrdquo

1645-1700 Tommaso Giovannini ldquoDevelopment of Theoretical Approaches to Model the

Spectral Properties of Complex Systemsrdquo

1700-1745 Invited ndash Marco Garavelli

Towards an accurate computational photochemistry and photobiology the

paradigmatic case of vision

1745-1900 Assemblea della Divisione di Chimica Teorica e Computazionale della SCI

Venerdigrave 21 Settembre Sessione 6 Chairman Emilia Sicilia

915-1000 Invited ndash Gianni Cardini

Modellizzazione in fase condensata ad alte pressioni

1000-1015 Fortuna Ponte ldquoComputational investigation of the platinum(IV) anticancer

prodrugs reduction mechanism by L-ascorbic acidrdquo

1015-1030 Laura Falivene ldquoTuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behaviorrdquo

1030-1045 Eduardo Schiavo ldquoInvestigating photoelectrochemical properties of dye-electrode

interfaces with density functional embedding theoryrdquo

1045-1100 Tainah Dorina Marforio ldquoCarbon nanotubes (CNTS) as nano-reactors

regioselectivity and kinetics control for the bromination of N-phenylacetamide A

QMMM investigationrdquo

1100-1145 Coffee Break (Atrio edificio H3)

Sessione 7 Sessione premi e medaglie Nordio ndash del Re ndash Scrocco ndash Roetti

Chairman Vincenzo Barone

1145-1200 Premio del Re Francesco Avanzini ldquoThe Quantum Molecular Trajectoryrdquo

1200-1230 Premio Scrocco Francesco Muniz-Miranda

Studies on the optoelectronic properties of metal nanoclusters and complexes

1230-1300 Premio Roetti Lorenzo Maschio

Quantum chemistry of crystalline solids using a local basis set the CRYSTAL

and CRYSCOR codes

1300 Conclusioni

Conferenze su invito Nome DipartimentoIstituzione Titolo contributo n

Piero Decleva DSCF Universitagrave di Trieste

Solving the Schroumldinger equation in a box wavepackets

and continuum states

I1

Fabrizio Santoro

ICCOM-CNR Area della Ricerca

del CNR di Pisa

Mixed quantumclassical description of the effects of

nuclear motion in electronic spectroscopy and ultrafast

photophysics

I2

Ana B Muntildeoz

Garciacutea

Dipartimento di Fisica ldquoEttore

Pancinirdquo Universitagrave di Napoli

Federico II

Defective but effective the role of defects on the

electrocatalytic performance of oxide-based materials for

energy conversion

I3

Anna Painelli

Dipartimento SCVSA Universitagrave

di Parma

Solvent dynamics and energy transfer

a real time description

I4

Marco Garavelli

Dipartimento di Chimica

Industriale ldquoToso Montanarirdquo

Bologna

Towards an accurate computational photochemistry and

photobiology the paradigmatic case of vision

I5

Gianni Cardini

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave di Firenze

Modellizzazione in fase condensata ad alte pressioni I6

Premi

Nome DipartimentoIstituzione Titolo contributo premio

Lorenzo Maschio Dipartimento di Chimica

Universitagrave di Torino

Quantum chemistry of crystalline solids using a local

basis set the CRYSTAL and CRYSCOR codes

Roetti

Francesco Muniz-

Miranda

Gent Universiteit Belgieuml Studies on the optoelectronic properties of metal

nanoclusters and complexes

Scrocco

Francesco Avanzini Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova

The Quantum Molecular Trajectory del Re

Contributi Orali

Nome DipartimentoIstituzione Titolo contributo n

Sofia Canola

Dipartimento di Chimica ldquoG

Ciamicianrdquo University of

Bologna via F Selmi 2 Bologna

Italy

Vibrational and optical fingerprints of conjugated

biradicals from DFT and TDDFT calculations

O1

Marco

Mendolicchio

Scuola Normale Superiore I-

56126 Pisa Italy

New computational strategies for the calculation of

anharmonic force fields

O2

Loredana Edith

Daga

Diparimento di Chimica

Universitagrave di Torino

On Optimizing Gaussian Basis sets for Crystalline Solids O3

Emanuele Coccia

Dipartimento di Scienze

Chimiche Universitagrave di Padova

via Marzolo 1 Padova Italy

Wave function-based approach to probe coherence in

ultrafast molecular processes

O4

Amalia Velardo

Dipartimento Chimica e Biologia

ldquoAdolfo Zambellirdquo Universitagrave

degli Studi di Salerno Via G

Paolo II 84084-Fisciano Italy

Band Shapes of Singlet-Triplet Transitions

O5

Laura Zanetti-Polzi

Department of Physical and

Chemical Sciences University of

LAquila Via Vetoio (Coppito1)

67010 LAquila Italy

Modeling amide I infrared spectra of proteins insights

from a perturbative approach

O6

Mario Prejanograve

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende (CS) Italia

The effect of distortions of a covalent enzymatic

intermediate in Human Transketolase a computational

point of view

O7

F Sessa

Department of Chemistry

University of Rome ldquoLa

Sapienzardquo Rome Italy

La3+ ion in EAN aqueous mixtures a MD-XAS

investigation on the effect of water concentration

O8

Diego Cesario

- Department of Chemistry and

Pharmaceutical Sciences and

Amsterdam Center for Multiscale

Modeling Vrije Universiteit

Amsterdam De Boelelaan 1083

1081 HV Amsterdam The

Netherlands

- Department of Chemistry

Biology and Biotechnology

University of Perugia

via Elce di Sotto 8 I-06123

Perugia Italy

Source of Cooperativity in Hydrogen-Bonded

Supramolecular Polymers

O9

Gloria Mazzone Chimie ParisTech PSL Research

University CNRS Institut de

Recherche de Chimie Paris Paris

France

Aiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

O10

Michele Guerrini

Dipartimento FIM Universitagrave di

Modena e Reggio Emilia Italy

Solid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulations

O11

Mirco Zerbetto

Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova Padova 35313 Italia

Previsione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studio

O12

F Faglioni

DSCG Univ of Modena and

Reggio Emilia Modena Italy

Self interaction charge delocalization electrolyte

ionization

O13

Mattia Anzola

Dipartimento di Scienze

Chimiche della Vita e della

Sostenibilitagrave Ambientale

Universitagrave degli Studi di Parma

Italy

Optical spectra of molecular aggregates testing

approximation schemes

O14

Martina De Vetta

-Institute of Theoretical

Chemistry Faculty of Chemistry

University of Vienna Waumlhringer

Str 17 A-1090 Vienna Austria

-Departamento de u mica

Universidad Aut noma de Madrid

Francisco Tomaacutes y Valiente 7

28049 Cantoblanco Madrid Spain

Simulations of a liposomal assisted delivery of the

Temoporfin photosensitizer

O15

Matteo Masetti Department of Pharmacy and

Biotechnology (FaBiT) Alma

Mater Studiorum ndash University of

Bologna Italy

The best of both worlds combining Markov State Models

and Path Collective Variables to describe protein-ligand

binding

O16

Ida Ritacco

CNR-IOM co SISSA via

Bonomea 265 34136 Trieste Italy

The mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic

level multiscale simulations

O17

Tommaso

Giovannini

Scuola Normale Superiore Piazza

dei Cavalieri 7 Pisa IT

Development of Theoretical Approaches to Model the

Spectral Properties of Complex Systems

O18

Fortuna Ponte

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria

Computational investigation of the platinum(IV)

anticancer prodrugs reduction mechanism by L-ascorbic

acid

O19

Laura Falivene

KAUST Catalysis Center King

Abdullah University of Science

and Technology Thuwal 23955-

6900 Saudi Arabia

Tuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behavior

O20

E Schiavo

Department of Chemical Sciences

University of Naples Federico II

Comp Univ Monte SantrsquoAngelo

Via Cintia 21 80126 Naples Italy

Investigating photoelectrochemical properties of dye-

electrode interfaces with density functional embedding

theory

O21

Tainah Dorina

Marforio

Dipartimento di Chimica ldquoG

Ciamicianrdquo Alma Mater

Studiorum ndash Universitagrave di

Bologna via Selmi 2 40126

Bologna

Italy

CARBON NANOTUBES (CNTS) AS NANO-

REACTORS

REGIOSELECTIVITY AND KINETICS CONTROL

FOR

THE BROMINATION OF N-PHENYLACETAMIDE

A QMMM INVESTIGATION

O22

Poster Nome DipartimentoIstituzione Titolo contributo n

F Cappelluti

Universitagrave degli Studi dellrsquoAquila

- LrsquoAquila

F-RESP a fast and accurate polarizable force field P1

Francesco Tavanti

Department of Chemical and

Geological Sciences University of

Modena and Reggio Emilia Via

Campi 103 41125

Modena Italy

Natural compounds for Alzheimerrsquos disease treatment a

classical

Molecular Dynamics investigation

P2

E Bernes

Department of Chemical and

Pharmaceutical Sciences

University of Trieste 34127

Trieste Italy

Core-Electron Excitations in Dibenzothiophene

Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

P3

Baiano C

Department of Chemical Sciences

University of Naples Federico II

Ab initio characterization of CO2 photoreduction

mechanism at CuFeO2 delafossite electrode

P4

Davide Accomasso

Department of Chemistry and

Industrial Chemistry University

of Pisa Italy

Seeking new materials for singlet fission

covalent dimers as an alternative to molecular crystals

P5

Henry Adenusi

Chemistry Department University

of Rome ldquoLa Sapienzardquo Italy

Proton transfer mechanisms in protic ionic liquids P6

Giorgia Beata

Dipartimento di Chimica

Universitagrave di Torino Via Giuria 7

I-10125 Torino Italy

CRYSPLOT a new tool to visualize physical and

chemical properties of crystalline solids

P7

Marco Pagliai

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze via della Lastruccia 3

50019 Sesto Fiorentino (FI) Italy

Molecular dynamics simulations of zinc proteins a

new force field

P8

Eslam M Moustafa

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria I-87036 Aracavacta

di Rende (CS) Italy

Reduction of Pt(IV) anticancer drugs a DFT mechanistic

study

P9

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Rapid evaluation of dynamic disorder in organic

semiconductors

P10

Isabella Romeo

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P11

Marina

Macchiagodena

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze Via della Lastruccia 3 I-

50019 Sesto Fiorentino Italy

Improved force fields for molecular dynamics

simulations of zinc proteins

P12

Marco Fusegrave

Scuola Normale Superiore Piazza

dei Cavalieri 7 56126 Pisa Italy

Computational simulation of vibrationally resolved

spectra for spin‐forbidden transitionsforbidden transitions

P13

Tiziana Marino

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P14

Matteo Capone

Universitagrave dellrsquoAquila Italia Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

P15

J FREGONI

Dipartimento di scienze Fisiche

Informatiche e Matematiche

University of Modena and Reggio

Emilia I-41125 Modena Italy

Manipulating azobenzene photoisomerization

through strong light-molecule coupling

P16

Irene Conti

Dipartimento di Chimica

Industriale ldquo Toso Montanarirdquo

Universita  di Bologna Viale del

Risorgimento 4 I-40136 Bologna

Italy

Excitonic State evolution of DNA Stacked Thymines

Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

P17

Andrea Le Donne

Chemistry department University

of Rome ldquoLa Sapienzardquo Rome

Italy

Ionic Liquids and Proton Transfer A Computational

Study to Understand Dynamic Processes

P18

Franco Egidi

Scuola Normale Superiore 56126

Pisa Italy

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

P19

Arianna Massaro

Department of Chemical Science

University of Naples ldquoFederico

IIrdquo via Cintia 21 80126 Naples

Italy

Unveiling the role of structural features in Na insertion

mechanism at anatase surfaces new insights for Na-ion

batteries development

P20

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Hole Mobility in Organic Semiconductors A Second-

Order Cumulant Approach

P21

Mariagrazia Fortino

Universitagrave di Modena e Reggio

Emilia Modena 41125 Italy

On the Simulation of Vibrationally Resolved Electronic

Spectra of medium-size molecules the case of Styryl

Substituted BODIPYs

P22

Marco Medves Dipdi Scienze Chimiche e

Farmaceutiche Universitagrave di

Trieste

Theoretical Study on the Circular Dichroism of Chiral

Bimetallic Clusters Ag-Au

P23

Jonathan Campeggio

Universitagrave degli Studi di Padova DiTe2 Calcolo del tensore di diffusione per molecole

flessibili

P24

Edoardo Jun

Mattioli

Chemistry Department ldquoG

Ciamicianrdquo University of Bologna

Computational Investigation of Competitive

Reaction Mechanisms inside Carbon Nanotubes

P25

Sergio Rampino

SMART Laboratory Scuola

Normale Superiore Piazza dei

Cavalieri 7 56126 Pisa

Combined Orbital-spaceReal-space Analysis of

Chemical Bonding through Virtual Reality

P26

Josephine Alba Dipdi Chimica Universitagrave di

Roma La Sapienza

Efficient and Accurate Modelling of Conformational

Transitions in proteins comparison between two Src

kinase proteins

P27

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 4: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Venerdigrave 21 Settembre Sessione 6 Chairman Emilia Sicilia

915-1000 Invited ndash Gianni Cardini

Modellizzazione in fase condensata ad alte pressioni

1000-1015 Fortuna Ponte ldquoComputational investigation of the platinum(IV) anticancer

prodrugs reduction mechanism by L-ascorbic acidrdquo

1015-1030 Laura Falivene ldquoTuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behaviorrdquo

1030-1045 Eduardo Schiavo ldquoInvestigating photoelectrochemical properties of dye-electrode

interfaces with density functional embedding theoryrdquo

1045-1100 Tainah Dorina Marforio ldquoCarbon nanotubes (CNTS) as nano-reactors

regioselectivity and kinetics control for the bromination of N-phenylacetamide A

QMMM investigationrdquo

1100-1145 Coffee Break (Atrio edificio H3)

Sessione 7 Sessione premi e medaglie Nordio ndash del Re ndash Scrocco ndash Roetti

Chairman Vincenzo Barone

1145-1200 Premio del Re Francesco Avanzini ldquoThe Quantum Molecular Trajectoryrdquo

1200-1230 Premio Scrocco Francesco Muniz-Miranda

Studies on the optoelectronic properties of metal nanoclusters and complexes

1230-1300 Premio Roetti Lorenzo Maschio

Quantum chemistry of crystalline solids using a local basis set the CRYSTAL

and CRYSCOR codes

1300 Conclusioni

Conferenze su invito Nome DipartimentoIstituzione Titolo contributo n

Piero Decleva DSCF Universitagrave di Trieste

Solving the Schroumldinger equation in a box wavepackets

and continuum states

I1

Fabrizio Santoro

ICCOM-CNR Area della Ricerca

del CNR di Pisa

Mixed quantumclassical description of the effects of

nuclear motion in electronic spectroscopy and ultrafast

photophysics

I2

Ana B Muntildeoz

Garciacutea

Dipartimento di Fisica ldquoEttore

Pancinirdquo Universitagrave di Napoli

Federico II

Defective but effective the role of defects on the

electrocatalytic performance of oxide-based materials for

energy conversion

I3

Anna Painelli

Dipartimento SCVSA Universitagrave

di Parma

Solvent dynamics and energy transfer

a real time description

I4

Marco Garavelli

Dipartimento di Chimica

Industriale ldquoToso Montanarirdquo

Bologna

Towards an accurate computational photochemistry and

photobiology the paradigmatic case of vision

I5

Gianni Cardini

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave di Firenze

Modellizzazione in fase condensata ad alte pressioni I6

Premi

Nome DipartimentoIstituzione Titolo contributo premio

Lorenzo Maschio Dipartimento di Chimica

Universitagrave di Torino

Quantum chemistry of crystalline solids using a local

basis set the CRYSTAL and CRYSCOR codes

Roetti

Francesco Muniz-

Miranda

Gent Universiteit Belgieuml Studies on the optoelectronic properties of metal

nanoclusters and complexes

Scrocco

Francesco Avanzini Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova

The Quantum Molecular Trajectory del Re

Contributi Orali

Nome DipartimentoIstituzione Titolo contributo n

Sofia Canola

Dipartimento di Chimica ldquoG

Ciamicianrdquo University of

Bologna via F Selmi 2 Bologna

Italy

Vibrational and optical fingerprints of conjugated

biradicals from DFT and TDDFT calculations

O1

Marco

Mendolicchio

Scuola Normale Superiore I-

56126 Pisa Italy

New computational strategies for the calculation of

anharmonic force fields

O2

Loredana Edith

Daga

Diparimento di Chimica

Universitagrave di Torino

On Optimizing Gaussian Basis sets for Crystalline Solids O3

Emanuele Coccia

Dipartimento di Scienze

Chimiche Universitagrave di Padova

via Marzolo 1 Padova Italy

Wave function-based approach to probe coherence in

ultrafast molecular processes

O4

Amalia Velardo

Dipartimento Chimica e Biologia

ldquoAdolfo Zambellirdquo Universitagrave

degli Studi di Salerno Via G

Paolo II 84084-Fisciano Italy

Band Shapes of Singlet-Triplet Transitions

O5

Laura Zanetti-Polzi

Department of Physical and

Chemical Sciences University of

LAquila Via Vetoio (Coppito1)

67010 LAquila Italy

Modeling amide I infrared spectra of proteins insights

from a perturbative approach

O6

Mario Prejanograve

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende (CS) Italia

The effect of distortions of a covalent enzymatic

intermediate in Human Transketolase a computational

point of view

O7

F Sessa

Department of Chemistry

University of Rome ldquoLa

Sapienzardquo Rome Italy

La3+ ion in EAN aqueous mixtures a MD-XAS

investigation on the effect of water concentration

O8

Diego Cesario

- Department of Chemistry and

Pharmaceutical Sciences and

Amsterdam Center for Multiscale

Modeling Vrije Universiteit

Amsterdam De Boelelaan 1083

1081 HV Amsterdam The

Netherlands

- Department of Chemistry

Biology and Biotechnology

University of Perugia

via Elce di Sotto 8 I-06123

Perugia Italy

Source of Cooperativity in Hydrogen-Bonded

Supramolecular Polymers

O9

Gloria Mazzone Chimie ParisTech PSL Research

University CNRS Institut de

Recherche de Chimie Paris Paris

France

Aiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

O10

Michele Guerrini

Dipartimento FIM Universitagrave di

Modena e Reggio Emilia Italy

Solid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulations

O11

Mirco Zerbetto

Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova Padova 35313 Italia

Previsione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studio

O12

F Faglioni

DSCG Univ of Modena and

Reggio Emilia Modena Italy

Self interaction charge delocalization electrolyte

ionization

O13

Mattia Anzola

Dipartimento di Scienze

Chimiche della Vita e della

Sostenibilitagrave Ambientale

Universitagrave degli Studi di Parma

Italy

Optical spectra of molecular aggregates testing

approximation schemes

O14

Martina De Vetta

-Institute of Theoretical

Chemistry Faculty of Chemistry

University of Vienna Waumlhringer

Str 17 A-1090 Vienna Austria

-Departamento de u mica

Universidad Aut noma de Madrid

Francisco Tomaacutes y Valiente 7

28049 Cantoblanco Madrid Spain

Simulations of a liposomal assisted delivery of the

Temoporfin photosensitizer

O15

Matteo Masetti Department of Pharmacy and

Biotechnology (FaBiT) Alma

Mater Studiorum ndash University of

Bologna Italy

The best of both worlds combining Markov State Models

and Path Collective Variables to describe protein-ligand

binding

O16

Ida Ritacco

CNR-IOM co SISSA via

Bonomea 265 34136 Trieste Italy

The mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic

level multiscale simulations

O17

Tommaso

Giovannini

Scuola Normale Superiore Piazza

dei Cavalieri 7 Pisa IT

Development of Theoretical Approaches to Model the

Spectral Properties of Complex Systems

O18

Fortuna Ponte

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria

Computational investigation of the platinum(IV)

anticancer prodrugs reduction mechanism by L-ascorbic

acid

O19

Laura Falivene

KAUST Catalysis Center King

Abdullah University of Science

and Technology Thuwal 23955-

6900 Saudi Arabia

Tuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behavior

O20

E Schiavo

Department of Chemical Sciences

University of Naples Federico II

Comp Univ Monte SantrsquoAngelo

Via Cintia 21 80126 Naples Italy

Investigating photoelectrochemical properties of dye-

electrode interfaces with density functional embedding

theory

O21

Tainah Dorina

Marforio

Dipartimento di Chimica ldquoG

Ciamicianrdquo Alma Mater

Studiorum ndash Universitagrave di

Bologna via Selmi 2 40126

Bologna

Italy

CARBON NANOTUBES (CNTS) AS NANO-

REACTORS

REGIOSELECTIVITY AND KINETICS CONTROL

FOR

THE BROMINATION OF N-PHENYLACETAMIDE

A QMMM INVESTIGATION

O22

Poster Nome DipartimentoIstituzione Titolo contributo n

F Cappelluti

Universitagrave degli Studi dellrsquoAquila

- LrsquoAquila

F-RESP a fast and accurate polarizable force field P1

Francesco Tavanti

Department of Chemical and

Geological Sciences University of

Modena and Reggio Emilia Via

Campi 103 41125

Modena Italy

Natural compounds for Alzheimerrsquos disease treatment a

classical

Molecular Dynamics investigation

P2

E Bernes

Department of Chemical and

Pharmaceutical Sciences

University of Trieste 34127

Trieste Italy

Core-Electron Excitations in Dibenzothiophene

Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

P3

Baiano C

Department of Chemical Sciences

University of Naples Federico II

Ab initio characterization of CO2 photoreduction

mechanism at CuFeO2 delafossite electrode

P4

Davide Accomasso

Department of Chemistry and

Industrial Chemistry University

of Pisa Italy

Seeking new materials for singlet fission

covalent dimers as an alternative to molecular crystals

P5

Henry Adenusi

Chemistry Department University

of Rome ldquoLa Sapienzardquo Italy

Proton transfer mechanisms in protic ionic liquids P6

Giorgia Beata

Dipartimento di Chimica

Universitagrave di Torino Via Giuria 7

I-10125 Torino Italy

CRYSPLOT a new tool to visualize physical and

chemical properties of crystalline solids

P7

Marco Pagliai

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze via della Lastruccia 3

50019 Sesto Fiorentino (FI) Italy

Molecular dynamics simulations of zinc proteins a

new force field

P8

Eslam M Moustafa

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria I-87036 Aracavacta

di Rende (CS) Italy

Reduction of Pt(IV) anticancer drugs a DFT mechanistic

study

P9

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Rapid evaluation of dynamic disorder in organic

semiconductors

P10

Isabella Romeo

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P11

Marina

Macchiagodena

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze Via della Lastruccia 3 I-

50019 Sesto Fiorentino Italy

Improved force fields for molecular dynamics

simulations of zinc proteins

P12

Marco Fusegrave

Scuola Normale Superiore Piazza

dei Cavalieri 7 56126 Pisa Italy

Computational simulation of vibrationally resolved

spectra for spin‐forbidden transitionsforbidden transitions

P13

Tiziana Marino

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P14

Matteo Capone

Universitagrave dellrsquoAquila Italia Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

P15

J FREGONI

Dipartimento di scienze Fisiche

Informatiche e Matematiche

University of Modena and Reggio

Emilia I-41125 Modena Italy

Manipulating azobenzene photoisomerization

through strong light-molecule coupling

P16

Irene Conti

Dipartimento di Chimica

Industriale ldquo Toso Montanarirdquo

Universita  di Bologna Viale del

Risorgimento 4 I-40136 Bologna

Italy

Excitonic State evolution of DNA Stacked Thymines

Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

P17

Andrea Le Donne

Chemistry department University

of Rome ldquoLa Sapienzardquo Rome

Italy

Ionic Liquids and Proton Transfer A Computational

Study to Understand Dynamic Processes

P18

Franco Egidi

Scuola Normale Superiore 56126

Pisa Italy

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

P19

Arianna Massaro

Department of Chemical Science

University of Naples ldquoFederico

IIrdquo via Cintia 21 80126 Naples

Italy

Unveiling the role of structural features in Na insertion

mechanism at anatase surfaces new insights for Na-ion

batteries development

P20

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Hole Mobility in Organic Semiconductors A Second-

Order Cumulant Approach

P21

Mariagrazia Fortino

Universitagrave di Modena e Reggio

Emilia Modena 41125 Italy

On the Simulation of Vibrationally Resolved Electronic

Spectra of medium-size molecules the case of Styryl

Substituted BODIPYs

P22

Marco Medves Dipdi Scienze Chimiche e

Farmaceutiche Universitagrave di

Trieste

Theoretical Study on the Circular Dichroism of Chiral

Bimetallic Clusters Ag-Au

P23

Jonathan Campeggio

Universitagrave degli Studi di Padova DiTe2 Calcolo del tensore di diffusione per molecole

flessibili

P24

Edoardo Jun

Mattioli

Chemistry Department ldquoG

Ciamicianrdquo University of Bologna

Computational Investigation of Competitive

Reaction Mechanisms inside Carbon Nanotubes

P25

Sergio Rampino

SMART Laboratory Scuola

Normale Superiore Piazza dei

Cavalieri 7 56126 Pisa

Combined Orbital-spaceReal-space Analysis of

Chemical Bonding through Virtual Reality

P26

Josephine Alba Dipdi Chimica Universitagrave di

Roma La Sapienza

Efficient and Accurate Modelling of Conformational

Transitions in proteins comparison between two Src

kinase proteins

P27

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 5: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Conferenze su invito Nome DipartimentoIstituzione Titolo contributo n

Piero Decleva DSCF Universitagrave di Trieste

Solving the Schroumldinger equation in a box wavepackets

and continuum states

I1

Fabrizio Santoro

ICCOM-CNR Area della Ricerca

del CNR di Pisa

Mixed quantumclassical description of the effects of

nuclear motion in electronic spectroscopy and ultrafast

photophysics

I2

Ana B Muntildeoz

Garciacutea

Dipartimento di Fisica ldquoEttore

Pancinirdquo Universitagrave di Napoli

Federico II

Defective but effective the role of defects on the

electrocatalytic performance of oxide-based materials for

energy conversion

I3

Anna Painelli

Dipartimento SCVSA Universitagrave

di Parma

Solvent dynamics and energy transfer

a real time description

I4

Marco Garavelli

Dipartimento di Chimica

Industriale ldquoToso Montanarirdquo

Bologna

Towards an accurate computational photochemistry and

photobiology the paradigmatic case of vision

I5

Gianni Cardini

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave di Firenze

Modellizzazione in fase condensata ad alte pressioni I6

Premi

Nome DipartimentoIstituzione Titolo contributo premio

Lorenzo Maschio Dipartimento di Chimica

Universitagrave di Torino

Quantum chemistry of crystalline solids using a local

basis set the CRYSTAL and CRYSCOR codes

Roetti

Francesco Muniz-

Miranda

Gent Universiteit Belgieuml Studies on the optoelectronic properties of metal

nanoclusters and complexes

Scrocco

Francesco Avanzini Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova

The Quantum Molecular Trajectory del Re

Contributi Orali

Nome DipartimentoIstituzione Titolo contributo n

Sofia Canola

Dipartimento di Chimica ldquoG

Ciamicianrdquo University of

Bologna via F Selmi 2 Bologna

Italy

Vibrational and optical fingerprints of conjugated

biradicals from DFT and TDDFT calculations

O1

Marco

Mendolicchio

Scuola Normale Superiore I-

56126 Pisa Italy

New computational strategies for the calculation of

anharmonic force fields

O2

Loredana Edith

Daga

Diparimento di Chimica

Universitagrave di Torino

On Optimizing Gaussian Basis sets for Crystalline Solids O3

Emanuele Coccia

Dipartimento di Scienze

Chimiche Universitagrave di Padova

via Marzolo 1 Padova Italy

Wave function-based approach to probe coherence in

ultrafast molecular processes

O4

Amalia Velardo

Dipartimento Chimica e Biologia

ldquoAdolfo Zambellirdquo Universitagrave

degli Studi di Salerno Via G

Paolo II 84084-Fisciano Italy

Band Shapes of Singlet-Triplet Transitions

O5

Laura Zanetti-Polzi

Department of Physical and

Chemical Sciences University of

LAquila Via Vetoio (Coppito1)

67010 LAquila Italy

Modeling amide I infrared spectra of proteins insights

from a perturbative approach

O6

Mario Prejanograve

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende (CS) Italia

The effect of distortions of a covalent enzymatic

intermediate in Human Transketolase a computational

point of view

O7

F Sessa

Department of Chemistry

University of Rome ldquoLa

Sapienzardquo Rome Italy

La3+ ion in EAN aqueous mixtures a MD-XAS

investigation on the effect of water concentration

O8

Diego Cesario

- Department of Chemistry and

Pharmaceutical Sciences and

Amsterdam Center for Multiscale

Modeling Vrije Universiteit

Amsterdam De Boelelaan 1083

1081 HV Amsterdam The

Netherlands

- Department of Chemistry

Biology and Biotechnology

University of Perugia

via Elce di Sotto 8 I-06123

Perugia Italy

Source of Cooperativity in Hydrogen-Bonded

Supramolecular Polymers

O9

Gloria Mazzone Chimie ParisTech PSL Research

University CNRS Institut de

Recherche de Chimie Paris Paris

France

Aiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

O10

Michele Guerrini

Dipartimento FIM Universitagrave di

Modena e Reggio Emilia Italy

Solid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulations

O11

Mirco Zerbetto

Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova Padova 35313 Italia

Previsione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studio

O12

F Faglioni

DSCG Univ of Modena and

Reggio Emilia Modena Italy

Self interaction charge delocalization electrolyte

ionization

O13

Mattia Anzola

Dipartimento di Scienze

Chimiche della Vita e della

Sostenibilitagrave Ambientale

Universitagrave degli Studi di Parma

Italy

Optical spectra of molecular aggregates testing

approximation schemes

O14

Martina De Vetta

-Institute of Theoretical

Chemistry Faculty of Chemistry

University of Vienna Waumlhringer

Str 17 A-1090 Vienna Austria

-Departamento de u mica

Universidad Aut noma de Madrid

Francisco Tomaacutes y Valiente 7

28049 Cantoblanco Madrid Spain

Simulations of a liposomal assisted delivery of the

Temoporfin photosensitizer

O15

Matteo Masetti Department of Pharmacy and

Biotechnology (FaBiT) Alma

Mater Studiorum ndash University of

Bologna Italy

The best of both worlds combining Markov State Models

and Path Collective Variables to describe protein-ligand

binding

O16

Ida Ritacco

CNR-IOM co SISSA via

Bonomea 265 34136 Trieste Italy

The mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic

level multiscale simulations

O17

Tommaso

Giovannini

Scuola Normale Superiore Piazza

dei Cavalieri 7 Pisa IT

Development of Theoretical Approaches to Model the

Spectral Properties of Complex Systems

O18

Fortuna Ponte

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria

Computational investigation of the platinum(IV)

anticancer prodrugs reduction mechanism by L-ascorbic

acid

O19

Laura Falivene

KAUST Catalysis Center King

Abdullah University of Science

and Technology Thuwal 23955-

6900 Saudi Arabia

Tuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behavior

O20

E Schiavo

Department of Chemical Sciences

University of Naples Federico II

Comp Univ Monte SantrsquoAngelo

Via Cintia 21 80126 Naples Italy

Investigating photoelectrochemical properties of dye-

electrode interfaces with density functional embedding

theory

O21

Tainah Dorina

Marforio

Dipartimento di Chimica ldquoG

Ciamicianrdquo Alma Mater

Studiorum ndash Universitagrave di

Bologna via Selmi 2 40126

Bologna

Italy

CARBON NANOTUBES (CNTS) AS NANO-

REACTORS

REGIOSELECTIVITY AND KINETICS CONTROL

FOR

THE BROMINATION OF N-PHENYLACETAMIDE

A QMMM INVESTIGATION

O22

Poster Nome DipartimentoIstituzione Titolo contributo n

F Cappelluti

Universitagrave degli Studi dellrsquoAquila

- LrsquoAquila

F-RESP a fast and accurate polarizable force field P1

Francesco Tavanti

Department of Chemical and

Geological Sciences University of

Modena and Reggio Emilia Via

Campi 103 41125

Modena Italy

Natural compounds for Alzheimerrsquos disease treatment a

classical

Molecular Dynamics investigation

P2

E Bernes

Department of Chemical and

Pharmaceutical Sciences

University of Trieste 34127

Trieste Italy

Core-Electron Excitations in Dibenzothiophene

Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

P3

Baiano C

Department of Chemical Sciences

University of Naples Federico II

Ab initio characterization of CO2 photoreduction

mechanism at CuFeO2 delafossite electrode

P4

Davide Accomasso

Department of Chemistry and

Industrial Chemistry University

of Pisa Italy

Seeking new materials for singlet fission

covalent dimers as an alternative to molecular crystals

P5

Henry Adenusi

Chemistry Department University

of Rome ldquoLa Sapienzardquo Italy

Proton transfer mechanisms in protic ionic liquids P6

Giorgia Beata

Dipartimento di Chimica

Universitagrave di Torino Via Giuria 7

I-10125 Torino Italy

CRYSPLOT a new tool to visualize physical and

chemical properties of crystalline solids

P7

Marco Pagliai

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze via della Lastruccia 3

50019 Sesto Fiorentino (FI) Italy

Molecular dynamics simulations of zinc proteins a

new force field

P8

Eslam M Moustafa

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria I-87036 Aracavacta

di Rende (CS) Italy

Reduction of Pt(IV) anticancer drugs a DFT mechanistic

study

P9

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Rapid evaluation of dynamic disorder in organic

semiconductors

P10

Isabella Romeo

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P11

Marina

Macchiagodena

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze Via della Lastruccia 3 I-

50019 Sesto Fiorentino Italy

Improved force fields for molecular dynamics

simulations of zinc proteins

P12

Marco Fusegrave

Scuola Normale Superiore Piazza

dei Cavalieri 7 56126 Pisa Italy

Computational simulation of vibrationally resolved

spectra for spin‐forbidden transitionsforbidden transitions

P13

Tiziana Marino

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P14

Matteo Capone

Universitagrave dellrsquoAquila Italia Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

P15

J FREGONI

Dipartimento di scienze Fisiche

Informatiche e Matematiche

University of Modena and Reggio

Emilia I-41125 Modena Italy

Manipulating azobenzene photoisomerization

through strong light-molecule coupling

P16

Irene Conti

Dipartimento di Chimica

Industriale ldquo Toso Montanarirdquo

Universita  di Bologna Viale del

Risorgimento 4 I-40136 Bologna

Italy

Excitonic State evolution of DNA Stacked Thymines

Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

P17

Andrea Le Donne

Chemistry department University

of Rome ldquoLa Sapienzardquo Rome

Italy

Ionic Liquids and Proton Transfer A Computational

Study to Understand Dynamic Processes

P18

Franco Egidi

Scuola Normale Superiore 56126

Pisa Italy

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

P19

Arianna Massaro

Department of Chemical Science

University of Naples ldquoFederico

IIrdquo via Cintia 21 80126 Naples

Italy

Unveiling the role of structural features in Na insertion

mechanism at anatase surfaces new insights for Na-ion

batteries development

P20

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Hole Mobility in Organic Semiconductors A Second-

Order Cumulant Approach

P21

Mariagrazia Fortino

Universitagrave di Modena e Reggio

Emilia Modena 41125 Italy

On the Simulation of Vibrationally Resolved Electronic

Spectra of medium-size molecules the case of Styryl

Substituted BODIPYs

P22

Marco Medves Dipdi Scienze Chimiche e

Farmaceutiche Universitagrave di

Trieste

Theoretical Study on the Circular Dichroism of Chiral

Bimetallic Clusters Ag-Au

P23

Jonathan Campeggio

Universitagrave degli Studi di Padova DiTe2 Calcolo del tensore di diffusione per molecole

flessibili

P24

Edoardo Jun

Mattioli

Chemistry Department ldquoG

Ciamicianrdquo University of Bologna

Computational Investigation of Competitive

Reaction Mechanisms inside Carbon Nanotubes

P25

Sergio Rampino

SMART Laboratory Scuola

Normale Superiore Piazza dei

Cavalieri 7 56126 Pisa

Combined Orbital-spaceReal-space Analysis of

Chemical Bonding through Virtual Reality

P26

Josephine Alba Dipdi Chimica Universitagrave di

Roma La Sapienza

Efficient and Accurate Modelling of Conformational

Transitions in proteins comparison between two Src

kinase proteins

P27

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 6: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Diego Cesario

- Department of Chemistry and

Pharmaceutical Sciences and

Amsterdam Center for Multiscale

Modeling Vrije Universiteit

Amsterdam De Boelelaan 1083

1081 HV Amsterdam The

Netherlands

- Department of Chemistry

Biology and Biotechnology

University of Perugia

via Elce di Sotto 8 I-06123

Perugia Italy

Source of Cooperativity in Hydrogen-Bonded

Supramolecular Polymers

O9

Gloria Mazzone Chimie ParisTech PSL Research

University CNRS Institut de

Recherche de Chimie Paris Paris

France

Aiming at Color Prediction of Flexible Dyes in Aqueous

Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

O10

Michele Guerrini

Dipartimento FIM Universitagrave di

Modena e Reggio Emilia Italy

Solid-state effects on the optical excitation of push-pull

molecular J-aggregates by first principles simulations

O11

Mirco Zerbetto

Dipartimento di Scienze

Chimiche Universitagrave degli Studi

di Padova Padova 35313 Italia

Previsione dei Tempi di Rilassamento NMR di Molecole

Flessibili Oligosaccaridi come Caso di Studio

O12

F Faglioni

DSCG Univ of Modena and

Reggio Emilia Modena Italy

Self interaction charge delocalization electrolyte

ionization

O13

Mattia Anzola

Dipartimento di Scienze

Chimiche della Vita e della

Sostenibilitagrave Ambientale

Universitagrave degli Studi di Parma

Italy

Optical spectra of molecular aggregates testing

approximation schemes

O14

Martina De Vetta

-Institute of Theoretical

Chemistry Faculty of Chemistry

University of Vienna Waumlhringer

Str 17 A-1090 Vienna Austria

-Departamento de u mica

Universidad Aut noma de Madrid

Francisco Tomaacutes y Valiente 7

28049 Cantoblanco Madrid Spain

Simulations of a liposomal assisted delivery of the

Temoporfin photosensitizer

O15

Matteo Masetti Department of Pharmacy and

Biotechnology (FaBiT) Alma

Mater Studiorum ndash University of

Bologna Italy

The best of both worlds combining Markov State Models

and Path Collective Variables to describe protein-ligand

binding

O16

Ida Ritacco

CNR-IOM co SISSA via

Bonomea 265 34136 Trieste Italy

The mechanism of post-translation regulation of estrogen

biosynthesis in Breast cancer cells as revealed by atomic

level multiscale simulations

O17

Tommaso

Giovannini

Scuola Normale Superiore Piazza

dei Cavalieri 7 Pisa IT

Development of Theoretical Approaches to Model the

Spectral Properties of Complex Systems

O18

Fortuna Ponte

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria

Computational investigation of the platinum(IV)

anticancer prodrugs reduction mechanism by L-ascorbic

acid

O19

Laura Falivene

KAUST Catalysis Center King

Abdullah University of Science

and Technology Thuwal 23955-

6900 Saudi Arabia

Tuning Proximal and Remote Steric Effects in the

Rationalization of Catalytic Behavior

O20

E Schiavo

Department of Chemical Sciences

University of Naples Federico II

Comp Univ Monte SantrsquoAngelo

Via Cintia 21 80126 Naples Italy

Investigating photoelectrochemical properties of dye-

electrode interfaces with density functional embedding

theory

O21

Tainah Dorina

Marforio

Dipartimento di Chimica ldquoG

Ciamicianrdquo Alma Mater

Studiorum ndash Universitagrave di

Bologna via Selmi 2 40126

Bologna

Italy

CARBON NANOTUBES (CNTS) AS NANO-

REACTORS

REGIOSELECTIVITY AND KINETICS CONTROL

FOR

THE BROMINATION OF N-PHENYLACETAMIDE

A QMMM INVESTIGATION

O22

Poster Nome DipartimentoIstituzione Titolo contributo n

F Cappelluti

Universitagrave degli Studi dellrsquoAquila

- LrsquoAquila

F-RESP a fast and accurate polarizable force field P1

Francesco Tavanti

Department of Chemical and

Geological Sciences University of

Modena and Reggio Emilia Via

Campi 103 41125

Modena Italy

Natural compounds for Alzheimerrsquos disease treatment a

classical

Molecular Dynamics investigation

P2

E Bernes

Department of Chemical and

Pharmaceutical Sciences

University of Trieste 34127

Trieste Italy

Core-Electron Excitations in Dibenzothiophene

Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

P3

Baiano C

Department of Chemical Sciences

University of Naples Federico II

Ab initio characterization of CO2 photoreduction

mechanism at CuFeO2 delafossite electrode

P4

Davide Accomasso

Department of Chemistry and

Industrial Chemistry University

of Pisa Italy

Seeking new materials for singlet fission

covalent dimers as an alternative to molecular crystals

P5

Henry Adenusi

Chemistry Department University

of Rome ldquoLa Sapienzardquo Italy

Proton transfer mechanisms in protic ionic liquids P6

Giorgia Beata

Dipartimento di Chimica

Universitagrave di Torino Via Giuria 7

I-10125 Torino Italy

CRYSPLOT a new tool to visualize physical and

chemical properties of crystalline solids

P7

Marco Pagliai

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze via della Lastruccia 3

50019 Sesto Fiorentino (FI) Italy

Molecular dynamics simulations of zinc proteins a

new force field

P8

Eslam M Moustafa

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria I-87036 Aracavacta

di Rende (CS) Italy

Reduction of Pt(IV) anticancer drugs a DFT mechanistic

study

P9

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Rapid evaluation of dynamic disorder in organic

semiconductors

P10

Isabella Romeo

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P11

Marina

Macchiagodena

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze Via della Lastruccia 3 I-

50019 Sesto Fiorentino Italy

Improved force fields for molecular dynamics

simulations of zinc proteins

P12

Marco Fusegrave

Scuola Normale Superiore Piazza

dei Cavalieri 7 56126 Pisa Italy

Computational simulation of vibrationally resolved

spectra for spin‐forbidden transitionsforbidden transitions

P13

Tiziana Marino

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P14

Matteo Capone

Universitagrave dellrsquoAquila Italia Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

P15

J FREGONI

Dipartimento di scienze Fisiche

Informatiche e Matematiche

University of Modena and Reggio

Emilia I-41125 Modena Italy

Manipulating azobenzene photoisomerization

through strong light-molecule coupling

P16

Irene Conti

Dipartimento di Chimica

Industriale ldquo Toso Montanarirdquo

Universita  di Bologna Viale del

Risorgimento 4 I-40136 Bologna

Italy

Excitonic State evolution of DNA Stacked Thymines

Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

P17

Andrea Le Donne

Chemistry department University

of Rome ldquoLa Sapienzardquo Rome

Italy

Ionic Liquids and Proton Transfer A Computational

Study to Understand Dynamic Processes

P18

Franco Egidi

Scuola Normale Superiore 56126

Pisa Italy

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

P19

Arianna Massaro

Department of Chemical Science

University of Naples ldquoFederico

IIrdquo via Cintia 21 80126 Naples

Italy

Unveiling the role of structural features in Na insertion

mechanism at anatase surfaces new insights for Na-ion

batteries development

P20

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Hole Mobility in Organic Semiconductors A Second-

Order Cumulant Approach

P21

Mariagrazia Fortino

Universitagrave di Modena e Reggio

Emilia Modena 41125 Italy

On the Simulation of Vibrationally Resolved Electronic

Spectra of medium-size molecules the case of Styryl

Substituted BODIPYs

P22

Marco Medves Dipdi Scienze Chimiche e

Farmaceutiche Universitagrave di

Trieste

Theoretical Study on the Circular Dichroism of Chiral

Bimetallic Clusters Ag-Au

P23

Jonathan Campeggio

Universitagrave degli Studi di Padova DiTe2 Calcolo del tensore di diffusione per molecole

flessibili

P24

Edoardo Jun

Mattioli

Chemistry Department ldquoG

Ciamicianrdquo University of Bologna

Computational Investigation of Competitive

Reaction Mechanisms inside Carbon Nanotubes

P25

Sergio Rampino

SMART Laboratory Scuola

Normale Superiore Piazza dei

Cavalieri 7 56126 Pisa

Combined Orbital-spaceReal-space Analysis of

Chemical Bonding through Virtual Reality

P26

Josephine Alba Dipdi Chimica Universitagrave di

Roma La Sapienza

Efficient and Accurate Modelling of Conformational

Transitions in proteins comparison between two Src

kinase proteins

P27

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 7: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Poster Nome DipartimentoIstituzione Titolo contributo n

F Cappelluti

Universitagrave degli Studi dellrsquoAquila

- LrsquoAquila

F-RESP a fast and accurate polarizable force field P1

Francesco Tavanti

Department of Chemical and

Geological Sciences University of

Modena and Reggio Emilia Via

Campi 103 41125

Modena Italy

Natural compounds for Alzheimerrsquos disease treatment a

classical

Molecular Dynamics investigation

P2

E Bernes

Department of Chemical and

Pharmaceutical Sciences

University of Trieste 34127

Trieste Italy

Core-Electron Excitations in Dibenzothiophene

Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

P3

Baiano C

Department of Chemical Sciences

University of Naples Federico II

Ab initio characterization of CO2 photoreduction

mechanism at CuFeO2 delafossite electrode

P4

Davide Accomasso

Department of Chemistry and

Industrial Chemistry University

of Pisa Italy

Seeking new materials for singlet fission

covalent dimers as an alternative to molecular crystals

P5

Henry Adenusi

Chemistry Department University

of Rome ldquoLa Sapienzardquo Italy

Proton transfer mechanisms in protic ionic liquids P6

Giorgia Beata

Dipartimento di Chimica

Universitagrave di Torino Via Giuria 7

I-10125 Torino Italy

CRYSPLOT a new tool to visualize physical and

chemical properties of crystalline solids

P7

Marco Pagliai

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze via della Lastruccia 3

50019 Sesto Fiorentino (FI) Italy

Molecular dynamics simulations of zinc proteins a

new force field

P8

Eslam M Moustafa

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria I-87036 Aracavacta

di Rende (CS) Italy

Reduction of Pt(IV) anticancer drugs a DFT mechanistic

study

P9

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Rapid evaluation of dynamic disorder in organic

semiconductors

P10

Isabella Romeo

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P11

Marina

Macchiagodena

Dipartimento di Chimica ldquoUgo

Schiffrdquo Universitagrave degli Studi di

Firenze Via della Lastruccia 3 I-

50019 Sesto Fiorentino Italy

Improved force fields for molecular dynamics

simulations of zinc proteins

P12

Marco Fusegrave

Scuola Normale Superiore Piazza

dei Cavalieri 7 56126 Pisa Italy

Computational simulation of vibrationally resolved

spectra for spin‐forbidden transitionsforbidden transitions

P13

Tiziana Marino

Dipartimento di Chimica e

Tecnologie Chimiche Universitagrave

della Calabria Rende I-87036

Italy

De novo proteins Insights from the theoretical

investigations

P14

Matteo Capone

Universitagrave dellrsquoAquila Italia Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

P15

J FREGONI

Dipartimento di scienze Fisiche

Informatiche e Matematiche

University of Modena and Reggio

Emilia I-41125 Modena Italy

Manipulating azobenzene photoisomerization

through strong light-molecule coupling

P16

Irene Conti

Dipartimento di Chimica

Industriale ldquo Toso Montanarirdquo

Universita  di Bologna Viale del

Risorgimento 4 I-40136 Bologna

Italy

Excitonic State evolution of DNA Stacked Thymines

Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

P17

Andrea Le Donne

Chemistry department University

of Rome ldquoLa Sapienzardquo Rome

Italy

Ionic Liquids and Proton Transfer A Computational

Study to Understand Dynamic Processes

P18

Franco Egidi

Scuola Normale Superiore 56126

Pisa Italy

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

P19

Arianna Massaro

Department of Chemical Science

University of Naples ldquoFederico

IIrdquo via Cintia 21 80126 Naples

Italy

Unveiling the role of structural features in Na insertion

mechanism at anatase surfaces new insights for Na-ion

batteries development

P20

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Hole Mobility in Organic Semiconductors A Second-

Order Cumulant Approach

P21

Mariagrazia Fortino

Universitagrave di Modena e Reggio

Emilia Modena 41125 Italy

On the Simulation of Vibrationally Resolved Electronic

Spectra of medium-size molecules the case of Styryl

Substituted BODIPYs

P22

Marco Medves Dipdi Scienze Chimiche e

Farmaceutiche Universitagrave di

Trieste

Theoretical Study on the Circular Dichroism of Chiral

Bimetallic Clusters Ag-Au

P23

Jonathan Campeggio

Universitagrave degli Studi di Padova DiTe2 Calcolo del tensore di diffusione per molecole

flessibili

P24

Edoardo Jun

Mattioli

Chemistry Department ldquoG

Ciamicianrdquo University of Bologna

Computational Investigation of Competitive

Reaction Mechanisms inside Carbon Nanotubes

P25

Sergio Rampino

SMART Laboratory Scuola

Normale Superiore Piazza dei

Cavalieri 7 56126 Pisa

Combined Orbital-spaceReal-space Analysis of

Chemical Bonding through Virtual Reality

P26

Josephine Alba Dipdi Chimica Universitagrave di

Roma La Sapienza

Efficient and Accurate Modelling of Conformational

Transitions in proteins comparison between two Src

kinase proteins

P27

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 8: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Franco Egidi

Scuola Normale Superiore 56126

Pisa Italy

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

P19

Arianna Massaro

Department of Chemical Science

University of Naples ldquoFederico

IIrdquo via Cintia 21 80126 Naples

Italy

Unveiling the role of structural features in Na insertion

mechanism at anatase surfaces new insights for Na-ion

batteries development

P20

Alessandro Landi

Dipartimento di Chimica e

Biologia Adolfo Zambelli

Universitagrave di Salerno Via

Giovanni Paolo II I-84084

Fisciano (SA) Italy

Hole Mobility in Organic Semiconductors A Second-

Order Cumulant Approach

P21

Mariagrazia Fortino

Universitagrave di Modena e Reggio

Emilia Modena 41125 Italy

On the Simulation of Vibrationally Resolved Electronic

Spectra of medium-size molecules the case of Styryl

Substituted BODIPYs

P22

Marco Medves Dipdi Scienze Chimiche e

Farmaceutiche Universitagrave di

Trieste

Theoretical Study on the Circular Dichroism of Chiral

Bimetallic Clusters Ag-Au

P23

Jonathan Campeggio

Universitagrave degli Studi di Padova DiTe2 Calcolo del tensore di diffusione per molecole

flessibili

P24

Edoardo Jun

Mattioli

Chemistry Department ldquoG

Ciamicianrdquo University of Bologna

Computational Investigation of Competitive

Reaction Mechanisms inside Carbon Nanotubes

P25

Sergio Rampino

SMART Laboratory Scuola

Normale Superiore Piazza dei

Cavalieri 7 56126 Pisa

Combined Orbital-spaceReal-space Analysis of

Chemical Bonding through Virtual Reality

P26

Josephine Alba Dipdi Chimica Universitagrave di

Roma La Sapienza

Efficient and Accurate Modelling of Conformational

Transitions in proteins comparison between two Src

kinase proteins

P27

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 9: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Abstracts delle conferenze su invito

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 10: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

I1

Solving the Schroumldinger equation in a box wavepackets and continuum states

Piero Decleva

DSCF Universitarsquo di Trieste declevaunitsit

ABSTRACT

Nelle molecole gli stati elettronici piursquo bassi decadono esponenzialmente con unrsquoestensione spaziale molto limitata Questo non ersquo piursquo vero per

- Stati Rydberg con alti numeri quantici - Stati del continuo - Pacchetti generati da impulsi elettromagnetici molto intensi

In tal caso le basi LCAO costruite da GTO o STO risultano inadeguate e sono necessari approcci alternativi sia funzioni di base diverse sia uso di griglie numeriche Per lo studio del continuo elettronico abbiamo da tempo sviluppato un set basato sullrsquouso di B-spline [1] come funzioni radiali adoperate nel modo LCAO convenzionale che si ersquo dimostrato assai flessibile e accurato Queste forniscono unrsquoeccellente rappresentazione delle soluzioni dellrsquoequazione di Schroumldinger allrsquointerno di una sfera di raggio prefissato arbitrario Calcoli dei parametri di fotoionizzazione molecolare a livello DFT [2] o TDDFT [3] forniscono generalmente risultati in buon accordo con lrsquoesperimento anche per sistemi relativamente grandi e per un gran numero di osservabili di fotoionizzazione sezioni drsquourto distribuzioni angolari di molecole con orientazione fissa o casuale parametri non-dipolari effetti di interferenza e diffrazione parametri chirali Ersquo stata anche applicata a fotoionizzazione risolta nel tempo da stati eccitati in esperimenti pump-probe e alla generazione di pacchetti di cationi da impulsi ultraveloci Piursquo recentemente la base ersquo stata applicata al calcolo di pacchetti drsquoonda eccitati da impulsi laser in regime non perturbativo Durante lrsquoimpulso lrsquoescursione dellrsquoelettrone puorsquo raggiungere migliaia di unitarsquo atomiche ma lrsquoapproccio ersquo numericamente molto stabile e si presta bene all propagazione del pacchetto per risoluzione dellrsquoequazione temporale Ersquo stata considerata la ionizzazione totale in funzione dellrsquoorientazione del campo rispetto alla molecola [4] il calcolo dello spettro di elettroni risolto in energia ed angolo attraverso la proiezione sugli autostati del continuo la rivelazione di pacchetti elettronici coerenti in esperimenti pump-probe agli attosecondi [5] la generazione di armoniche alte (HHG) [6] Verranno illustrati alcuni risultati recenti e discusse le linee di sviluppo

REFERENCES

1 H Bachau E Cormier P Decleva J E Hansen and F Martin ldquoApplications of B-splines in Atomic and Molecular Physicsrdquo

Reports on Progress in Physics 64 1815 (2001)

2 D Toffoli M Stener G Fronzoni and P Decleva ldquoConvergenge of the Multicenter B-spline DFT approach for the continuumrdquo

Chem Phys 276 25 (2002)

3 M Stener G Fronzoni and P Decleva ldquoTime-dependent density-functional theory for molecular photoionization with

noniterative algorithm and multicenter B-spline basis set CS2 and C6H6 case studiesrdquoJ Chem Phys 122 (2005) 234301

4 S Petretti YV Vanne A Saenz A Castro and P Decleva ldquoAlignment-Dependent Ionization of N2 O2 and CO2 in Intense

Laser Fieldsrdquo Phys Rev Letters 104 (2010) 223001

5 M Ruberti P Decleva and V Averbukh ldquoMulti-channel dynamics and correlation-driven inter-channel couplings in high

harmonic generation spectra of aligned CO2 molecule ab initio Time Dependent B-spline ADC ab initio analysisrdquo Phys Chem

Chem Phys 20 (2018) 8311

6 E Plesiat M Lara-Astiaso P Decleva A Palacios and F Martin ldquoReal-time determination of ultrafast charge dynamics in

tetrafluoromethane from attosecond pump-probe photoelectron spectroscopyrdquo Chem Eur J 242018 xxx

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 11: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

I2

Mixed quantumclassical description of the effects of nuclear motion in electronic spectroscopy and ultrafast

photophysics

Fabrizio Santoro1

1 ICCOM-CNR Area della Ricerca del CNR di Pisa Italy 2 Affiliazione 2

fabriziosantoroiccomcnrit

ABSTRACT

Quantum nuclear effects can play a relevant role in determining the shape of electronic spectra and the fate of the photoexcited dynamics in molecular systems Recent advancements in fully quantum vibronic approaches for the computation of spectra [12] and in quantum-dynamical (QD) approaches like those provided by the MCTDH method [3-5] allow an efficient description of such effects even in large systems if they are rigid (harmonic) and in gas phase Flexible systems or systems embedded in solvents or in heterogenoeus media possibly establishing with them specific interactions represent a challenge for fully quantum treatments of nuclear motions Classical and semi-classical trajectory based approaches are very well suited to deal with these cases but they neglect quantum nuclear effects We believe that the development of wise mixed quantum classical (MQC) approaches may represent a suitable framework to overcome some of these present limitations In this contribution we present our recent work in this field In electronic spectroscopy we introduced mixed schemes that separate fast and slow degrees of freedom (DoF) on the grounds of an adiabatic approximation and treat the fast DoF at quantum level and the slow ones (including the solvent) at classical level The spectra are then naturally expressed as an average of vibronic spectra involving along the fast DoF over the distribution of the classical DoF [5-7] Extending these ideas to ultrafast photophysical processes we recently proposed a MQC approach to introduce environmental dynamical effects in QD simulations In its simplest version all the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics while the motion of an explicit solvent model is described by an ensemble of classical trajectories The core idea of the method is to describe the mutual coupling of the solute and solvent dynamics within a mean-field framework In this way the Hamiltonians of both the quantum and classical subsystems contain time-dependent terms due to the interaction with the other subset and the quantum and classical equations of motions are solved simultaneously We will discuss the potentialities limitations and possible perspectives of these methods with a number of test applications

REFERENCES

1 Barone V WIREs Comput Mol Sci 2016 6 86-110 2 Santoro F Jacquemin D WIREs Comput Mol Sci 2016 6 460-486 3 Wang H Thoss M J Chem Phys 2003 119 1289minus1299 Vendrell O Meyer H-D J Chem Phys 2011 134 044135 4 Beck M H J ckle A Worth G A Meyer H-D Phys Rep 2000 324 1minus105 5 CerezoJ Avila F Prampolini G Santoro F J Chem Theory Comput 2015 11 5810ndash5825

6 Cerezo J Mazzeo G Longhi G Abbate S Santoro F J Phys Chem Lett 2016 7 4891‐4897 7 Cerezo J Aranda D Avila F Mazzeo G Longhi G Abbate S Santoro F Chirality 2018 30 730ndash743 8 Cerezo J Liu Y Lin N Zhao X Improta R Santoro F J Chem Theory Comput 201814 820ndash832

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 12: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

I3

Defective but effective the role of defects on the electrocatalytic performance of oxide-based materials

for energy conversion

Ana B Muntildeoz Garciacutea1

1 Dipartimento di Fisica ldquoEttore Pancinirdquo Universitagrave di Napoli Federico II

Comp Univ Monte S Angelo via Cintia 21 80126 Napoli (Italia)

anabelenmunozgarciauninait

ABSTRACT

Ab initio simulations play an increasingly important role in materials sciences In the energy conversion scenario computational modeling can elucidate with atomic resolution the subtle composition-structure-property relationships behind the performance of functional materials and complex interfaces In heterogeneous electrocatalysis the underlying bulk and surface chargemass transport events are often strongly dependent on the presenceabsence of structural defects Thus a deep knowledge of defect chemistry is key for understanding tuning and optimizing the properties of different catalysts In particular this contribution will report recent advances in the DFT-based characterization of the role of defects in strongly correlated oxides as electrodes in electrocatalytic devices Three case studies will be presented (i) a new triple-conducting oxide based on Sr2Fe15Mo05O6 perovskite with promising bifunctional catalytic activity towards oxygen reduction and evolution reactions [1-3] (ii) Fe-doped ZrO2 for low temperature PEMFCs [4] and (iii) CuFeO2 delafossite for CO2 photoreduction [5] In all these cases we will discuss how surface oxygen vacancies -boosted by aliovalent doping- can improve the electrode performance and change product selectivity In conclusion this contribution will highlight the merits of computationally driven materials discovery in the context of energy conversion devices pointing out the importance of the necessary interplay between theory and experiment

REFERENCES

1 ABMG D Bugaris M Pavone J P Hodges A Huq F Chen H-C zur Loye E A Carter J Am Chem Soc 134 6826 (2012) 2 ABMG M Pavone Chem Mater 28 490 (2016) 3 ABMG M Pavone J Mater Chem A 5 12735 (2017) 4 P Madkikar D Menga G Harzer T Mittermeier A Siebel F E Wagner M Merz S Schuppler P Nagel ABMG M Pavone H A Gasteiger M Piana Submitted 5 J Gu A Wuttig J W Krizan Y Hu Z M Detweller R J Cava A B Bocarsly J Phys Chem C 117 12415 (2013)

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 13: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

I4

Solvent dynamics and energy transfer a real time description

Anna Painelli Francesco Di Maiolo

Dipartimento SCVSA Universitagrave di Parma annapainelliuniprit

ABSTRACT

Energy dissipation and relaxation phenomena are crucial to describe the dynamics of excited states The interaction of a molecule with the environment (the bath) is pivotal in this respect bringing theoretical chemistry towards the field of open quantum systems Several strategies are available to quantitatively describe the system-bath interaction most often based on the dynamics of the reduced density matrix Vibrational degrees of freedom must be explicitly described to address internal conversion and the huge dimension of the resulting basis imposes dramatic approximations to the calculation Here we face the problem adopting an essential state model (ESM) description of the molecular systems ESMs proved successful in describing low-energy linear and non-linear optical spectra of several families of organic dyes in terms of a minimal number of electronic states coupled to few effective vibrational modes ESMs successfully account for polar solvation and for intermolecular interactions in molecular aggregates and in energy transfer systems (1 2 3)

Here we present a dynamical non-adiabatic model for Resonance Energy Transfer (RET) Specifically we consider two dyes an energy donor (D) and an energy acceptor (A) Each dye corresponds to a push-pull chromophore described in terms of two electronic states coupled to a single effective vibration Accounting for dissipation phenomena within the Redfield approach we follow the real time dynamics of RET from the excited D towards A (Fig1 left panel) Moreover a newly derived multistate Redfield-Smoluchowski equation is used to investigate how the dynamical disorder induced by polar solvation affects RET (Fig1 right panel)

REFERENCES

1 F Terenziani A Painelli PhysChemChemPhys 17 13074-81 (2015) 2 C Sissa et al Phys Chem Chem Phys 2011 13 12734ndash12744 3 S Sanyal et al PhysChemChemPhys 2017 19 24979

Fig 1 Resonance

Energy Transfer in real

time Left Non-

adiabatic QUOTE

dynamics

following impulsive

excitation of the energy

donor the adiabatic

potential energy

surfaces are shown for

reference Right

temporal evolution of

the population of the

excited energy acceptor

in a frozen and liquid

polar solvent

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 14: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

I5

Towards an accurate computational photochemistry and photobiology the paradigmatic case of vision

Marco Garavelli1

1 Dipartimento di Chimica Industriale ldquoToso Montanarirdquo Viale del Risorgimento 4 40136 Bologna Italy 2 Affiliazione 2

marcogaravelliuniboit

ABSTRACT

The use of the computer to simulate light induced events in photoactive molecular materials has given access to a detailed description of the molecular motions and mechanisms underlying the reactivity of organic and bio-organic chromophores Thus different computational strategies and tools can now be operated like a ―virtual spectrometer to characterize and understand the photoinduced molecular deformation and reactivity of a given dye allowing for an accurate description of photochemicalphotobiological processes and a rational of the corresponding photophysical properties including time-resolved spectroscopy

This contribution reviews recent advances in this field by presenting methodological developments and applications in modeling the photophysicalphotochemical properties of organic chromophores and complex photoactive molecular architectures Retinal systems and visual proteins will be presented as a paradigmatic case [12] Hybrid QMMM calculations will be shown to be an elective tool for modeling photoinduced events and dynamics including tuningcontrolling effects of the environment For this purpose our new implementation of a general hybrid QMMM approach that is able to integrate some specialized softwares and acts as a flexible computational environment eventually allowing for so far inaccessible calculations (eg non-adiabatic molecular dynamics of unprecedented accuracy on large molecular materials) will be illustrated The information collected by these studies can be exploited for the design of novel photoactive molecular and soft materials including a novel paradigm of electrochromism for applications in a new generation of color tunable displays and e-ink devices Finally our latest achievements in developing (and modeling) non-linear bi-dimensional electronic spectroscopy as a novel diagnostic tool for tracking structuraldynamical problems in complex environments (eg biologically relevant systems such as proteins and DNA) will be presented [34]

REFERENCES

1 D Polli et al Nature 467 (2010) 440 2 B Demoulin et al JPCL 8 (2017) 4407 3 I Rivalta et al PCCP 16 (2014) 16865 4 I Rivalta et al JPCB 118 (2014) 8396

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 15: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

I6

Modellizzazione in fase condensata ad alte pressioni

Gianni Cardini

Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave di Firenze email giannicardiniunifiit

ABSTRACT

La modellizzazione delle proprietagrave strutturali e dinamiche di sistemi in fase condensata dipende essenzialmente dalla corretta descrizione del potenziale di interazione intermolecolare In simulazioni di dinamica molecolare1 si ricorre di solito a modelli di potenziale semi empirici o a metodi ab initio12 nella maggior parte dei casi basati sulla teoria del funzionale della densitagrave (DFT) Nel caso di sistemi sottoposti ad alte pressioni diventa cruciale una corretta descrizione delle interazioni a corto raggio e modelli che consentano eventualmente la rottura e formazione di legami chimici Verranno presentati alcuni risultati di simulazioni di dinamica molecolare ab initio con il metodo Car Parrinello Le simulazioni ab initio su fasi condensate basate su sistemi periodici sono dispendiose e pertanto condotte per tempi brevi e su campioni molto piccoli Inoltre nel campo delle alte pressioni gli sperimentali sono soliti interpretare i dati spettroscopici in termini di proprietagrave di singola molecola e necessitano di una modellizzazione possibilmente veloce per interpretare le loro misure Questo puograve essere ottenuto ricorrendo al metodo XP-PCM proposto da Cammi et al3 che consente di ottenere risultati qualitativi effettuando calcoli in condizioni estreme di pressione su singola molecola

REFERENCES

7 MP Allen amp DJ Tildesley Computer Simulation of Liquids Oxford University Press Oxford UK 2017 8 DMarx and J Hutter Ab Initio Molecular Dynamics Cambridge University Press Cambridge UK 2009 9 R Cammi et al Chem Phys 344 (2008) 135 R Cammi et al J ChemPhys 137 (2012) 154112

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 16: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Abstracts dei contributi orali

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 17: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O1

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 18: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O2

New computational strategies for the calculation of anharmonic force fields

Marco Mendolicchio1 Julien Bloino1 Vicenzo Barone1

1 Scuola Normale Superiore I-56126 Pisa Italy

marcomendolicchiosnsit

ABSTRACT

Spectroscopies such as infrared and Raman are powerful tools for the investigation of the physical-chemical properties of molecular systems providing detailed information related to the structure and dynamics However experimental spectra are tuned by several intertwined effects which can make the interpretation of experimental data very challenging or even unfeasible without the support of reliable computational models [1] From this point of view improvements in the accuracy of calculations can be made by introducing anharmonic effects to the description of nuclear motions In particular the second-order vibrational perturbation theory (VPT2) [2] has been known to offer a good balance between accuracy and computational cost thus permitting the study of medium-to-large systems A prerequisite is the knowledge of the potential energy surface (PES) expanded as a Taylor series in terms of the nuclear coordinates about a reference configuration [3] In practice a semi-diagonal quartic force field is necessary to compute the anharmonic vibrational transition energies

Currently the most common way to obtain third- and fourth-order energy derivatives is through finite differences of analytic second-order derivatives of the PES [45] which have shown their efficiency and reliability for a large range of cases This approach is generally well adapted when the degree of anharmonicity of a given vibration is relatively limited but is not flexible enough to support higher-order derivatives necessary to describe correctly large amplitude motions (LAMs) or when harmonic force constants are not available analytically Hence the standard approach to build the anharmonic PES can become a daunting task and alternative strategies need to be explored In this work a new least-squares fitting approach has been devised and combined with a dynamical sampling scheme where an initial default grid is improved iteratively during the calculation in order to adapt to the shape of the PES

In this contribution the underlying theory and the main features of our computational protocol are presented The procedure described above is not exclusively related to PESs and can be extended to property surfaces This approach has been designed from the outset in order to be completely expandable to properties definable as functions of the nuclear coordinates such as dipole moments and polarizability tensors The convergence of the results can then be monitored for each property separately In this work the sampling used for the semi-diagonal quartic force field has been also used to obtain the set of dipole moment derivatives required for computing anharmonic infrared intensities within the VPT2 framework [5-8] and then the full infrared spectrum

REFERENCES

1 M Biczysko J Bloino and C Puzzarini Wiley Interdiscp Rev Comput Mol Sci 8 (2017) e1349 2 H H Nielsen Rev Mod Phys 23 (1951) 90 3 A G Csaacuteszaacuter Wiley Interdiscp Rev Comput Mol Sci 2 (2012) 273 4 V Barone J Chem Phys 122 (2005) 014108 5 J Bloino A Baiardi M Biczysko Int J Quantum Chem 116 (2016) 1543 6 A Willetts N C Handy W H Green and D Jayatilaka J Chem Phys 94 (1990) 5608 7 J Vaacutezquez and J F Stanton Molecular Physics 104 (2006) 377 8 J Bloino and V Barone J Chem Phys 136 (2012) 124108

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 19: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O3

On Optimizing Gaussian Basis sets for Crystalline Solids

Loredana Edith Daga1 Lorenzo Maschio1

1 Diparimento di Chimica Universitagrave di Torino lorenzomaschiounitoit

ABSTRACT

CRYSTAL is a well known ab initio code for solid-state quantum-mechanical simulations one of its peculiar aspects is that it is based on Gaussian type functions1

Although the local nature of the basis allows an accurate description of the electronic distribution in periodic systems allowing for the easy and relatively cheap use of hybrid functionals the calibration-optimization of exponents and coefficients for each atomic species is quite often not straightforward Despite recent attempts2 standardized and well-assessed libraries of basis sets are not available for solids as they are for molecules One reason for that is the wide chemical diversity of different solids where the same atomic species can be present as an ion a covalently bonded atom or involved in a metallic bond

For all of these reasons optimization of a basis set can be system specific and is nowadays often left in the hands of the user In this view we have developed a novel method to optimize the basis sets that we call BDIIS (Basis set Direct Inversion of Iterative Subspace) The method is an application of the well known DIIS algorithm34 to the optimization of basis sets in the spirit of its geometry-optimization variant (GDIIS)5

The DIIS method is today a standard tool in quantum chemistry and provides a significant acceleration of the SCF (self-consistent field) convergence rate The method involves the construction of a suitable error vector at each iteration and its minimization implicates the SCF convergence In a similar manner BDIIS requires the construction of an error vector that in this case instead of being related to SCF parameters is based on previous values of both exponents and coefficients A double-sided numerical derivatives are used as gradients and they are scaled by a suitable scale factor obtained by a line search method We implemented the BDIIS algorithm in the CRYSTAL code1 and in this contribution details of the method and first results will be presented

REFERENCES

1 Roberto Dovesi Alessandro Erba Roberto Orlando Claudio M Zicovich-Wilson

Bartolomeo Civalleri Lorenzo Maschio Michel Reacuterat Silvia Casassa Jacopo Baima Simone Salustro Bernard Kirtman Quantum-mechanical condensed matter simulations with CRYSTAL WIREs Comput Mol Sci 8e1360 2018

2 T Bredow M F Peintinger D V Oliveira Consistent gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations J Comput Chem 34451-459 2013

3 Maschio L Direct Inversion of the Iterative Subspace (DIIS) convergence accelerator for crystalline solids employing Gaussian basis sets Theoretical Chemistry Accounts 13760 2018

4 P Pulay Convergence acceleration of iterative sequences The case of scf iteration Chem Phys 73393-398 1980

5 P Csaacuteszaacuter and P Pulay Geometry Optimization by Direct Inversion in the Iterative Subspace J Mol Struct Elsevier Science Publisher 11431-34 1984

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 20: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O4

Wave function-based approach to probe coherence in ultrafast molecular processes

Emanuele Coccia1 Filippo Troiani2 Stefano Corni12

1 Dipartimento di Scienze Chimiche Universitagrave di Padova via Marzolo 1 Padova Italy 2 Istituto di Nanoscienze CNR via Campi 213A Modena Italy

emanuelecocciaunipdit

ABSTRACT

Revealing possible long-living quantum coherence in ultrafast processes allows detecting genuine quantum mechanical effects in complex systems such as materials and biomolecules [1] To investigate such effects from a quantum chemistry perspective we have developed methods to simulate the time evolution of molecular systems based on ab initio calculations that include the effect of an external medium (eg a solvent plasmonic nanoparticles) on the molecule [2] as well as of dephasing of the electronic wave function The latter has been accomplished by means of the stochastic Schroumldinger equation [3] To test the approach we have simulated [4] femtosecond pulse-shaping ultrafast spectroscopy of terrylenediimide [5] finding that the experimental results could be reproduced Then we have investigated the absorption of light pulses for a more complex system (a molecular chromophore close to a spherical silver nanoparticle) and we found that including dephasing is essential to provide a qualitatively correct picture of metal-enhanced molecular absorption that depends on the interplay of light pulse duration plasmon lifetime and molecular dephasing time [6] Moreover preliminary results on possible plasmon-enhanced high-harmonic generation are shown

REFERENCES

1 G D Scholes et al Nature 543 647 (2017) 2 S Pipolo and S Corni J Phys Chem C 120 28774 (2016) 3 R Biele and R DrsquoAgosta J Phys Condens Matter 24 273201 (2012) 4 E Coccia F Troiani and S Corni J Chem Phys 148 204112 (2018) 5 R Hildner D Brinks and N F van Hulst Nature Phys 7 172 (2011)

6 E Coccia and S Corni in preparation

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 21: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O5

Band Shapes of Singlet-Triplet Transitions

Amalia Velardo1 Raffaele Borrelli2 Amedeo Capobianco1 Alessandro Landi1 Andrea Peluso1

1 Dipartimento Chimica e Biologia ldquoAdolfo Zambellirdquo Universitagrave degli Studi di Salerno Via G Paolo II 84084-Fisciano Italy

2 Dipartimento di Scienze Agrarie Forestali e Alimentari Universitagrave degli Studi di Torino Largo Braccini 2 10095-Grugliasco Italy

avelardounisait

ABSTRACT

Triplet states have found a renewed interest because of the important role they play in organic

solid-state optoelectronic devices They are indeed involved in radiative and non radiative

transitions that can significantly affect device efficiency In organic light emitting diodes (OLED)

triplet excitons are preferentially formed over singlet excitons determining to a larger extent the

efficiency of emitted radiation In photovoltaic solar cells triplet states can in principle improve the

efficiency both for the long lifetime of triplet excitons that imply a large diffusion length and for

photon upconversion via triplet-triplet annihilation which provides higher energy photons

However low-lying triplet states could also provide potentially fast charge recombination channels

which can limit the efficiency of energy conversion

Herein we present a full quantum mechanics approach for evaluating from first principles the rates of radiative and radiationless singlet triplet transitions which could be useful for a deeper understanding of the role of triplet states in a solid state device For testing the reliability of the approach we have simulated the spectral band shapes of singlet-triplet transitions of some aromatic compounds used in optoelectronic devices[2] Computed spectral shapes are in excellent agreement with experimental results opening the way for reliable study of non radiative singlet-triplet transitions

REFERENCES

1 A Velardo R Borrelli A Capobianco M V La Rocca and A Peluso J Phys Chem C 119 (2015) 18870-18876 2 A Velardo R Borrelli A Peluso and A Capobianco J Phys Chem C 120 (2016) 24605-24614

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 22: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O6

Modeling amide I infrared spectra of proteins insights from a perturbative approach

Laura Zanetti-Polzi1 Massimiliano Aschi1 Andrea Amadei2 Isabella Daidone1

1 Department of Physical and Chemical Sciences University of LAquila Via Vetoio (Coppito1) 67010 LAquila Italy

2 Department of Chemical and Technological Sciences University of Rome ldquoTor Vergatardquo Via della Ricerca Scientifica 00185 Rome Italy laurazanettipolziunivaqit

ABSTRACT

Infrared (IR) absorption spectra of the amide I mode mostly corresponding to the peptide-group C=O stretching have long provided a tool for determining the secondary structure of peptides and proteins Indeed the frequencies of the amide I band are closely correlated to the molecular geometry and hydrogen bonding pattern However the link of particular frequencies with secondary structure has been made on the basis of semiempirical rules and is often controversial Moreover the observed amide I bands are often featureless due to the extensive overlap of the broad underlying component bands Theoreticalminuscomputational methods are needed to provide essential information on the complex relationship between spectroscopic absorption and dynamics permitting the effects of structural transitions and of solvent interactions on the IR signal to be unravelled In this context we proposed and applied an approach to calculate amide I IR spectra of peptides and proteins based on the joint use of extended molecular dynamics (MD) simulations and a mixed quantumclassical theoretical computational methodology the Perturbed Matrix Method (PMM)[1] The use of such an approach allowed the theoretical investigation of the amide I spectra of both helical [23] and β [3-5] peptides as well as amyloids [6] and peptides unfolded states [35] critically comparing the calculated spectra with experimental IR temperature-dependent and isotope-labelled spectra and providing a mean for the interpretation of the experimental spectra at the molecular level More recently we focused on modelling the time-dependence of the amide I IR signal to be compared with experimental time-resolved IR spectra commonly used to monitor folding kinetics [5] The possibility of quantitatively modelling time resolved spectra can provide a detailed interpretation of the time evolution of the spectroscopic signal permitting a full characterization of the kinetics of complex chemical-biochemical processes The investigation of time-dependent IR signals has been applied to the analysis of extremely long (hundreds of microseconds) folding trajectories of two β peptides [7] allowing to reconstruct the IR spectroscopic signal of various conformational states of the peptide and providing a thorough thermodynamic and kinetic picture of the folding process

REFERENCES

1 Amadei A et al Theor Chem Acc 129(1) 31-43 2011 2 Zanetti-Polzi L et al J Phys Chem B 117(41) 12383-12390 2013 3 Zanetti-Polzi L et al J Phys Chem B 116(10) 3353-3360 2012 4 Zanetti-Polzi L et al J Phys Chem B 115(41) 11872-11878 2011 5 Daidone I et al J Phys Chem B 119(14) 4849-4856 2015 6 Zanetti-Polzi L et al J Am Chem Soc 133(30) 11414-11417 2011

7 Zanetti‐ Polzi L et al FEBS Lett 591(20) 3265-32752017

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 23: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O7

The effect of distortions of a covalent enzymatic intermediate in Human Transketolase a computational

point of view

Mario Prejanograve1 Tiziana Marino1 Nino Russo 1 Fabiola Medina2 Pedro A Fernandes2 Maria J Ramos2

1 Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende (CS) Italia 2 Departemento de Quimica e Bioquimica Faculdade de Ciencias Universidade do Porto Porto Portugal

emalimarioprejanounicalit

ABSTRACT

Enzymes are biological catalyst that accelerate chemical reactions in time requested by physiological processes and are basically proteins that catalyze highly chemo- stereo- and region-selective reactions

Thanks to that ability from their discovery to nowadays several theories were proposed in order to understand explain and predict behavior of these incredible biological machines

Human Tranketolase is an enzyme belonging to transferase class participates to Pentose Phosphate Pathways and involved in different diseases metabolism like Alzheimerrsquos disease Most recently 1-3 the distortion contribution of a covalent intermediate (out of plane C-C bond C-C bond elongation) has been proposed as fundamental event to the catalysis according with Albery and Knowles theory4

Starting from literature work 3 an accurate computational study has been carried out with the aim of verify confirm and quantify the distortion contribution to the catalytic pathway applying different computational methodologies to different models with different size full ab initio hybrid QMMMONIOM and classical Molecular Dynamics protocols

The Gliceraldheyde-3-phospate formation step was estimated as rate determining step (16 kcalmol-1) according with experimental observations Along the Potential Energy Surface was calculated the effect of distortion observing that highest energy barrier decreases of 16 kcalmol-1

REFERENCES

1P Asztalos C Parthier R Golbik M Kleinschmidt G Hubner M S Weiss R Friedemann

G Wille K Tittmann Biochemistry 46 12037 2007

2L Mitschke C Parthier K Schroeder-Tittmann J Coy K Tittmann J Biol Chem 285

31559 2010 3

S Luumldtke P Neumann K M Erixon F Leeper R Kluger R Ficner K Tittmann Nat

Chem 5 762 2013 4 W J Albery J R Knowles Angew Chem Int Ed Engl 16 285 1977

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 24: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O8

La3+

ion in EAN aqueous mixtures a MD-XAS investigation on the effect of water concentration

F Sessa1 V Migliorati1 A Lapi12 P DrsquoAngelo1

1 Department of Chemistry University of Rome ldquoLa Sapienzardquo Rome Italy 2 CNR institute ldquoSezione Meccanismi di Reazionerdquo University of Rome ldquoLa Sapienzardquo Rome Italy

francescosessauniroma1it

ABSTRACT

Ranging from analytical chemistry to electrochemistry Ionic Liquids (ILs) are interesting compounds that have seen a wide array of applications including their use as replacement for organic solvents lubricants reaction and transport media Due to their low volatility and non-flammability as well as their high chemical and thermal stability ILs are safer and more environmental-friendly than the commonly used solvents(1) Since one of IL most interesting application is their use in the nuclear fuel cycle understanding at a molecular level the solvation process of lanthanoid (Ln3+) salts in IL solution is an important piece of information to improve the efficiency of extraction procedures for the separation of lanthanoid metals Taking into account that all ILs are highly hygroscopic it is also important to understand the effect of water on the coordination properties of Ln3+ solvation complexes in IL media

Here we have investigated the effect of water concentration on the structure of La3+ solvation complexes in several aqueous mixtures of ethylammonium nitrate (EAN) which is the most studied protic IL by means of a combination of X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations The MD-XAS approach has been already proven a valuable tool for the study of IL solutions the high selectivity and versatility of the XAS technique allows one to obtain reliable data on liquid samples while MD simulations provide a dynamic atomistic description of the systems(23)

We find that the presence of nitrate anions in the La3+ coordination complexes diminishes as the water content of the mixtures rises Unlike other weakly coordinating anions such as CF3SO3

- or ClO4

-(4) nitrate anions are still found in the coordination complexes at very high water content However nitrate anions do not behave as strongly coordinating anions either(4) as NO3

- does not saturate the coordination complexes unless the water content is very low This suggests that the coordination properties of Ln3+ ions in EAN aqueous mixtures can be suitably tuned by altering the water content of the solvent mixture

REFERENCES

1 M Freemantle An Introduction to Ionic Liquids RSC Publishing 2009 2 A Serva V Migliorati R Spezia P DrsquoAngelo Chem Eur J 23 8424-8433 (2017) 3 F Sessa V Migliorati A Serva A Lapi G Aquilanti G Mancini P DrsquoAngelo Phys Chem Chem Phys 20 2662-2675 (2018) 4 KBinnemans Comprehensive Inorganic Chemistry II Volume 2 Transition Elements Lanthanides and Actinides Elsevier 2013

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 25: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O9

Source of Cooperativity in Hydrogen-Bonded Supramolecular Polymers

Diego Cesario12 Stephanie C C van derLubbe1 Pascal Vermeeren1 Francesca Nunzi234 Ceacutelia Fonseca Guerra15

1 Department of Chemistry and Pharmaceutical Sciences and Amsterdam Center for Multiscale Modeling

Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands 2Department of Chemistry Biology and Biotechnology University of Perugia

via Elce di Sotto 8 I-06123 Perugia Italy 3Istituto di Scienze e Tecnologie Molecolari del CNR (ISTM-CNR)

via Elce di Sotto 8 I-06123 Perugia Italy 4Consortium for Computational Molecular and Materials Sciences (CMS)

2

via Elce di Sotto 8 I-06123 Perugia Italy 5Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University

P O Box 9502 2300 RA Leiden The Netherlands E-mail diegocesariostudentiunipgit

ABSTRACT

Cooperative self-assembly expands the possibilities in supramolecular chemistry Hydrogen bonds in long

polymeric chains can experience synergy which is often explained as a manifestation of aromaticity to

enhance hydrogen bonding between the monomers In this work linear chains of urea deltamide and

squaramide have been investigated computationally with dispersion-corrected density functional theory in

the framework of Kohn-Sham molecular orbital theory to shed light on the enhancement in the hydrogen

bonds from a quantum chemical perspective Our Energy Decomposition Analysis (EDA)1 shows that the

sources of the cooperativity are in the electrostatic and orbital contributions for this reason in urea the

same cooperativity is found as in deltamide and squaramide which become respectively a more regular a

triangle and square due to the hydrogen bonding The covalent component in the σ orbital interaction of

the hydrogen bonds plays a crucial role it induces a charge separation in the chains that allows a synergetic

lengthening of the polymers Although geometrical changes suggest an enhancement of the aromaticity

the charge transfer in the electronic system is the real driving force of the enhancement of the hydrogen

bond interactions

REFERENCES

1 Kohn‐ Sham Density Functional Theory Predicting and Understanding Chemistry In Reviews in Computational Chemistry

O10

Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 26: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

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Aiming at Color Prediction of Flexible Dyes in Aqueous Solution Combined Molecular Dynamic and Quantum

Mechanic approaches

Gloria Mazzone1 Stefania Di Tommaso1 Alistar Ottochian1 Ilaria Ciofini1 and Carlo Adamo1

1 Chimie ParisTech PSL Research University CNRS Institut de Recherche de Chimie Paris Paris France gloriamazzonechimieparistechpsleu

ABSTRACT

The accurate prediction of spectral features determining the color of dyes in complex environment represent a challenge for industrial research Setting-up a computational protocol allowing to quantitative simulation of the perceived color would provide a cost-effective alternative to the synthesis and characterization of new compounds enabling the design of new dyes with customized properties within shorter time scale

For structurally rigid dyes a theoretical protocol based on a quantum mechanical description in the framework of Time-Dependent Density Functional Theory (TDDFT) in implicit solvent environment allows the prediction of the absorption band shape and position since for such systems the vibronic coupling based on the Frank Condon assumption is expected to be a valid model [1] While the simulation of flexible dyes optical properties requires efficient protocols able to explicitly account for the intrinsic complexity of both solute and solvent Therefore a model that explicitly takes into account the environment embedding the solute has to be considered A procedure based on combination of molecular dynamics and quantum mechanical approaches represent the most promising strategy to reach this aim [2-3]

In this work the spectroscopic properties of various flexible dyes in aqueous solution have been investigated through a theoretical approach combining a classical dynamic sampling of the whole system by using a non-reparametrized force field with TDDFT calculations of the dye under investigation The QM calculations have been performed on representative snapshots chosen as function of the selected degree of freedom taking into account the solvent effects using an implicit model (PCM) and weighing each transition with a Boltzmann distribution to achieve the final spectrum

REFERENCES

1 S Di Tommaso D Bousquet D Moulin F Baltenneck P Riva H David A Fadli J Gomar I Ciofini C Adamo J Comput Chem 2017 38 998

2 N De Mitri S Monti G Prampolini V Barone J Chem Theory Comput 2013 9 4507 3 J Cerezo F J Avila Ferrer G Prampolini F Santoro J Chem Theory Comput 2015 11 5810

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Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

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Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 27: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O11

Solid-state effects on the optical excitation of push-pull molecular J-aggregates by first

principles simulations

Michele Guerrini1 Arrigo Calzolari2 and Stefano Corni23

1Dipartimento FIM Universitagrave di Modena e Reggio Emilia Italy

2CNR Nano Istituto Nanoscienze Centro S3 I-41125 Modena Italy

3Dipartimento di Scienze Chimiche Universitagrave di Padova Italy

micheleguerriniunimoreit

ABSTRACT

J-aggregates1 are a class of low-dimensional molecular crystals which display enhanced interaction with

light These systems show interesting optical properties as an intense and narrow red-shifted absorption peak

(J-band)2-5

with respect to the spectrum of the corresponding monomer The need to theoretically investigate

optical excitations in J-aggregates is two-fold a thorough first principles description is still missing and a

renewed interest is raising recently in understanding the nature of the J-band in particular regarding the

collective mechanisms involved in its formation In this work we investigate the electronic and optical

properties of a J-aggregate molecular crystal made of ordered arrangements of organic push-pull

chromophores6 By using a time-dependent density functional theory approach we assess the role of the

molecular packing in the enhancement and red-shift of the J-band along with the effects of confinement in

the optical absorption when moving from bulk to low-dimensional crystal structures We simulate the

optical absorption of different configurations (ie monomer dimers a polymer chain and a monolayer sheet)

extracted from the bulk crystal By analyzing the induced charge density associated to the J-band we

conclude that it is a longitudinal excitation delocalized along parallel linear chains and that its overall red-

shift results from competing coupling mechanisms some giving red shift and others giving blue shift which

derive from both coupling between transition densities and renormalization of the single particle energy

levels

REFERENCES

1 Jelley E E Spectral Absorption and Fluorescence of Dyes in the Molecular State Nature 1936 138 1009-1010

2 Wuumlrthner F Kaiser T E Saha-Moumlller C R J-aggregates from serendipitous discovery to supramolecular

engineering of functional dye materials Angew Chem Int Ed 2011 50 3376-3410

3 Egorov V V Alfimov M V Theory of the J-band From the Frenkel exciton to charge transfer Phys -Usp 2007 50

985

4 Eisfeld A Briggs J S The J-band of organic dyes lineshape and coherence length Chem Phys 2002 281 61-70

5 Eisfeld A Briggs J S The J- and H-bands of organic dye aggregates Chem Phys 2006 324 376-384

6 Botta C Cariati E Cavallo G Dichiarante V Forni A Metrangolo P Pilati T Resnati G Righetto S Terraneo

G Tordin E J Mater Chem C 2014 2 5275-5279

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 28: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O12

Previsione dei Tempi di Rilassamento NMR di Molecole Flessibili Oligosaccaridi come Caso di Studio

Mirco Zerbetto1 Antonino Polimeno1 Goumlran Widmalm2

1 Dipartimento di Scienze Chimiche Universitagrave degli Studi di Padova Padova 35313 Italia 2 Department of Organic Chemistry Stockholm University S-106 91 Stockholm Sweden

mircozerbettounipdit

ABSTRACT

Le misure di rilassamento di risonanza magnetica nucleare (NMR) di molecole in cui uno o piugrave atomi vengono arricchiti isotopicamente (ad es 2H 13C 15N 17O) non solo sono in grado di fornire informazioni strutturali di una molecola (dai gruppi funzionali presenti alla struttura 3D in soluzione) ma sono anche sensibili alla dinamica molecolare a tempi lunghi

LrsquoNMR egrave particolarmente diffusa nello studio della dinamica di molecole biologiche [1] sistemi che possono presentare un elevato grado di flessibilitagrave (si pensi ad esempio alle proteine intrinsecamente disordinate) La dinamica influenza perograve in maniera indiretta e complessa i dati sperimentali quali i tempi di rilassamento spin-spin e spin-reticolo per cui sono necessari modelli interpretativi della dinamica molecolare e in particolare delle dinamiche lente Se da una parte il confronto tra il dato sperimentale e il modello teorico puograve essere usato per estrapolare informazioni di natura molecolare da misure di rilassamento NMR lrsquoottica che spinge il progetto qui presentato egrave invece quella della previsione del comportamento a tempi lunghi di sistemi complessi attraverso la messa a punto di un protocollo multiscala per la simulazione ―ab initio di misure di rilassamento NMR che passa attraverso una scelta euristica delle coordinate rilevanti la definizione di una equazione di Smoluchowski per la dinamica stocastica di tali coordinate e lrsquoutilizzo di dinamiche molecolari Browniane per la propagazione della dinamica e il calcolo delle osservabili spettroscopiche [2]

Piccoli oligosaccaridi composti da 2-5 unitagrave zuccherine sono stati finora impiegati allo scopo di mettere a punto tale metodologia multiscala I carboidrati a differenza di altre molecole biologiche (proteine DNA) presentano diversi schemi di legame e possibilitagrave di ramificazione Per questo motivo sono un ottimo caso di studio percheacute richiedono lo sviluppo di modelli per la dinamica che siano sensibili a differenze anche molto localizzate a livello molecolare ma che possono condurre a proprietagrave anche molto diverse su scala temporale ampia Inoltre recentemente i carboidrati hanno attirato un elevato interesse tecnologico soprattutto le nanocellulose [3] Usando come leitmotiv gli oligosaccaridi si discuteragrave lrsquoapproccio sviluppato anche in termini della sua applicabilitagrave a sistemi piugrave complessi

REFERENCES

1 Sheppard D Spranger R Tugarinov V NMR Spettrosc 2010 56 1 2 Zerbetto M Polimeno A Int J Quantum Chem 2016 116 1706 3 Moon R J Martini A Nairn J Simonsen J Youngblood J Chem Soc Rev 2011 40 3941

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 29: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O13

Self interaction charge delocalization electrolyte ionization

F Faglioni1 WA Goddard III2 B Merinov2 E Fadel3 G Samsonidze3 N Molinari3 J Grossman3 J Mailoa3 B Kozinsky4

1 DSCG Univ of Modena and Reggio Emilia Modena Italy

2 MSSC California Institute of Technology Pasadena (CA) USA

3 Robert Bosh Research and Technology Center Boston (MA) USA

4 Paulson School of Engineering amp Appl Sciences Harvard University Boston (MA) USA

francescofaglioniunimoreit

ABSTRACT

We investigate the effect of charge delocalization associated to a lack of self interaction correction in many popular density functionals and its effect on the description of the decomposition pathway for several lithium battery electrolytes as observed during electrochemical cycling1 This effect has been known for decades2 and although is usually neglected for reactions involving closed shell systems or single uncharged radicals we show that it plays a fundamental role for anion ionization in solution where its inclusion changes the qualitative description of the ionization process and the subsequent decomposition pathway

After sceening a number of DFT methods we investigated four anions (TFSI(-) PF6(-) DTI(-) BF4(-)) and four solvents (DMSO DME PC AN) as potential components for next generation lithium-metal rechargeable batteries3

We provide a simple electrostatic model to explain the predicted behavior This model will guide electrochemists in the design of stable electrolytes and to determine recharging conditions to prevent or reduce cell failure

1 Nakyama M et al Energy Environ Sci 3 1995 (2010) 2 Johnson BG et al Chem Phys Lett 221 100 (1994) 3 E Fadel et al in preparation

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 30: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O14

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 31: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O15

Simulations of a liposomal assisted delivery of the Temoporfin photosensitizer

Martina De Vetta12 Omar Baig1 Juan J Nogueira1 Leticia Gonzaacutelez1

1 Institute of Theoretical Chemistry Faculty of Chemistry University of Vienna Waumlhringer Str 17 A-1090 Vienna Austria

2 Departamento de Quiacutemica Universidad Aut noma de Madrid Francisco Tomaacutes y Valiente 7 28049 Cantoblanco Madrid Spain

martinadevettaunivieacat

ABSTRACT

Assisted delivery formulations of photosensitizers employed in photodynamic therapy are currently applied or under development to solve the problems created by the hydrophobic nature of many of these compounds Liposomes are particularly suitable carriers thanks to the hydrophobicity of the inner double layer and the hydrophilic character of the outer surface The efficacy of such assisted delivery formulations is bounded to the inter-molecular interactions between the drug and the carrier material1 To provide insight on the nature of such interactions we have employed all-atom molecular dynamics to simulate the liposomal formulation of Temoporfin a porphyrin-based photosensitizer Atomistic resolution despite costly for such macromolecular assembly was essential to identify the origin of the exceptional loading capacity and the rigidity of the nano-carrier in the presence of the drug Temoporfin is found to be a rather good hydrogen donor and forms an extended hydrogen bond network with the polar heads of the phospholipids such short range and directional interactions modify the diffusion of the lipid molecules and assure the stability of the drug-liposome complex2 These intermolecular interactions are also expected to influence the delivery of the drug from the carrier to the targeted cells through the cellular membrane This process has been investigated with umbrella-sampling molecular dynamics Then the influence of the membrane hydrophobic environment on Temoporfin electronically excited states was also investigated In particular we have computed the UV-vis absorption spectrum and the lower tripletsrsquo density of states by an electrostatic-embedding QMMM scheme considering an ensemble of geometries at the minimum of the free-energy profile from the umbrella sampling simulation Such calculations have also been performed in methanol for which in addition different theoretical models and sampling techniques have been employed and compared to the experimental absorption spectrum measured in methanol

REFERENCES

1 A S L Derycke P A M De Witte Adv Drug Deliv Rev 2004 56 17ndash30 2 M De Vetta L Gonzaacutelez J J Nogueira ChemistryOpen (accepted) 2018

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 32: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O16

The best of both worlds combining Markov State Models and Path Collective Variables to describe

protein-ligand binding

Matteo Masetti1

1 Department of Pharmacy and Biotechnology (FaBiT) Alma Mater Studiorum ndash University of Bologna Italy matteomasetti4uniboit

ABSTRACT

A reliable estimation of binding affinities and binding rates is of paramount importance for computational drug discovery[1] Thanks to recent advances in hardware and sampling methodologies Molecular Dynamics (MD) simulations are becoming increasingly effective and they are emerging as a valid alternative to molecular docking (dynamic docking)[2] Typically two classes of orthogonal approaches based on MD frameworks can be envisioned Unbiased (or brute force) MD simulations followed by Markov State Models (MSM) analysis are gaining increasing popularity as they have the advantage of providing a comprehensive kinetic (and thermodynamic) picture of the process under investigation[3] Unfortunately unless unconventional computational resources are available the CPUGPU-intensive nature of this approach does not comply with an accurate characterization of rate constants[4] On the other hand biased-MD approaches like metadynamics[5] have proven to be effective in determining free energy profiles of complex events as long as suitable reaction coordinates (or collective variables CVs) are provided Among these Path Collective Variables (PCVs) represent an optimal choice to describe protein-ligand association but their effectiveness relies on a prior knowledge of the mechanism one wishes to characterize[6]

Here we present a combined approach suited to fully characterize the energetics of protein-ligand binding making optimal use of computational resources We apply the methodology to a pharmaceutically relevant problem like the association of Alprenolol to the β-adrenergic receptor for which a set of previously computed trajectories were made available[7] In particular the Markov states are firstly identified and then employed to feed PCVs Thus the free energy profile of Alprenolol binding is reconstructed via well-tempered metadynamics[8] The reliability of calculations is finally assessed through statistical analysis approaches

REFERENCES

1 Pan AC Borhani DW Dror RO Shaw DE Molecular determinants of drugndashreceptor binding kinetics Drug Discov Today 2013 18

2 Gioia D Bertazzo M Recanatini M Masetti M Cavalli A Dynamic docking a paradigm shift in computational drug discovery Molecules 2017 22

3 Husic BE Pande V Markov state models from an art to a science J Am Chem Soc 2018 140 4 De Vivo M Masetti M Bottegoni G Cavalli A Role of molecular dynamics and related methods in drug discovery J Med Chem

2016 59 5 Laio A Parrinello M Escaping free-energy minima Proc Natl Acad Sci USA 2002 99 6 Branduardi D Gervasio FL Parrinello M From A to B in free energy space J Chem Phys 2007 126 7 Dror RO Pan AC Arlow DH Borhani DW Maragakis P Shan Y Xu H Shaw DE Pathway and mechanism of drug

binding to G-protein-coupled receptors Proc Natl Acad Sci USA 2011 108 8 Barducci A Bussi G Parrinello M Well-tempered metadynamics a smoothly converging and tunable free-energy method Phys

Rev Lett 2008 100

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 33: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O17

The mechanism of post-translation regulation of estrogen biosynthesis in Breast cancer cells as revealed by atomic level multiscale simulations

Ida Ritacco1 Angelo Spinello1 Alessandra Magistrato1

1 CNR-IOM co SISSA via Bonomea 265 34136 Trieste Italy

HYPERLINK mailtoiritaccosissait

ABSTRACT

Human Aromatase (HA) is a heme-protein belonging to the cytochrome P450 family This

catalyzes the conversion of androgens to estrogens through reactions requiring oxygen and

electrons provided by NADPH cytochrome reductase (CPR)1 However high levels of estrogens

resulting from enhanced HA activity are related to abnormal cellular proliferation which leads to

several diseases among which breast cancer (BC) Recently it has been shown that post-

translational regulation of HA by the tyrosine 361 (Y361) phosphorylation up-regulates HA activity2

It is hypothesized that phosphorylated Y361 accelerates the electronic transfer (ET) from the CPR

to the heme of the HA enhancing estrogen biosynthesis Aim of this work was to rationalize both

the mechanism of post-translation regulation and the interaction mechanism of HA with CPR

combining different computational techniques eg protein-protein docking molecular dynamics

(MD) simulations and hybrid quantum-classical (QMMM) MD simulations These simulations

unprededently reveal that phosphorylation only slightly affects the ET rate between the FMN

domain of the CPR and HA while having the largest impact on the stabilization of the CPRHA

adduct

REFERENCES

1 1 Y Dai et al Steroids 2015 101 116-124 2 2 S Catalano et al Mini Rev Med Chem 2016 16(9) 691-698

HA

FMN domain of CPR

eoline

androgens

estrogens

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 34: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O18

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 35: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O19

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 36: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O20

Tuning Proximal and Remote Steric Effects in the Rationalization of Catalytic Behavior

Laura Falivene and Luigi Cavallo

KAUST Catalysis Center King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Email HYPERLINK mailtolaurafalivenekaustedusa

ABSTRACT

Rationalizing the behavior of transition metal catalysts often consists in relating their performance

to the steric and electronic properties of the ligand As for steric effects the classical Tolman cone

angle θ developed for phosphane type ligands certainly is among the most famous1 However this

descriptor is biased towards phosphanes which makes it less useful when different type of ligands

have to be analyzed In this scenario we developed another descriptor the percent of buried

volume VBur23 which has been used to correlate catalytic behavior to the structure of the catalyst

using typical structure-property relationships4

As typical for numerical descriptors the VBur only captures average properties of a given ligand

missing completely the way space occupation around the metal center occurs To overcome this

limitation we introduced topographic steric maps as a natural evolution of the VBur35 Steric maps

allow having a clear image of the surface of interaction between the transition metal based catalyst

and the substrate Nonetheless extracting numbers from steric maps to be used in multivariate

linear correlations aimed at rationalizing experimental behavior is not straightforward To this end

we developed a buried volume approach aimed at separating the coordination space around the

metal into proximal and remote zones In this contribution we will show how tuning the separation

between proximal and remote zones and how this separation allows to achieve good

rationalization of catalytic behavior in a series of test cases

REFERENCES

1 C A Tolman Chem Rev 1977 77 313-348 2 A Poater B Cosenza A Correa S Giudice F Ragone V Scarano L Cavallo Eur J Inorg Chem 2009 1759-1766 3 L Falivene R Credendino A Poater A Petta L Serra R Oliva V Scarano L Cavallo Organometallics 2016 35 2286-92 4 L Falivene L Cavallo G Talarico ACS Catal 2015 5 6815-21 5 F Ragone A Poater L Cavallo J Am Chem Soc 2010 132 4249-4258

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 37: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O21

Investigating photoelectrochemical properties of dye-electrode interfaces with density functional embedding

theory

E Schiavo1 A B Muntildeoz-Garciacutea2 F Libisch3 and M Pavone1

1 Department of Chemical Sciences University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

2 Department of Physics University of Naples Federico II Comp Univ Monte SantrsquoAngelo Via Cintia 21 80126 Naples Italy

3 Institute for Theoretical Physics Vienna University of Technology Wiedner Hauptstraszlige 8 Vienna eduardoschiavouninait

ABSTRACT

Dye-Sensitized Solar Cells (DSSCs) are complex photoelectrochemical devices where the interfaces between different components play a crucial role for the overall performance1 From the theoretical point of view the study of such interfaces presents many challenges for state of the art computational tools In particular the modelling of the photochemistry involving molecular dyes requires high levels of theory that are able to accurately treat excited states The standard computational approach for extended solid-state systems is Density Functional Theory (DFT) which by construction is only capable of treating ground state properties Conversely the realistic modelling of the electrode nanoparticles covered by anchored dyes requires a model system size that cannot be handled by accurate methods eg GW or correlated wavefunction approaches

In this contribution we propose to solve this problem by means of density functional- embedding theory (DFET)2-3 Briefly embedding methods allow partitioning of a system in two subsets the cluster and the environment The total energy is the sum of those from the two subsets plus an interaction term This partition allows us to treat the cluster with accurate and demanding methods while retaining the effects of the environment at the DFT level DFET defines a unique embedding potential mediating the interaction between the cluster and the environment The potential is obtained by a modified optimized effective potential method4 under the constraint that the sum of the densities of the subsets matches the density of the total system

In the past few years many works have been published on the development implementation and testing of different embedding schemes56 Most of these works focus on the performance of embedding methods when applied to benchmark systems Here we apply DFET for a real p-type DSSC interface model a Coumarin-based dye (C343) adsorbed on p-type NiO which is the current standard for DSSC photocathodes7 We test DFET by characterizing the electronic structure of the dye with methods beyond DFT while treating the NiO environment with DFT(+U) Our results assess the importance of having a proper embedding potential to obtain accurate results for the photochemical properties of adsorbed dyes in p-type DSSCs

REFERENCES

1 A Hagfeldt G Boschloo L Sun L Kloo and H Pettersson Chem Rev 110 (2010) 6595 2 C Huang M Pavone and E A Carter J Chem Phys 134 (2011) 154110 3 K Yu F Libisch and E A Carter J Chem Phys 143 (2015) 102806 4 Q Wu and W Yang J Chem Phys 118 (2003) 2494 5 S Prager A Zech F Aquilante A Dreuw T A Wesolowski J Chem Phys 144 (2016) 204103 6 F R Manby M Stella J D Goodpaster T F Miller III J Chme Theory Comput 8 (2012) 2564 7 A B Muntildeoz-Garciacutea and M Pavone Phys Chem Chem Phys 17 (2015) 12238

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 38: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

O22

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 39: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

Abstracts dei poster

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 40: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P1

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 41: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P2

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 42: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P3

Core-Electron Excitations in Dibenzothiophene Derivatives A Joint Experimental and Theoretical

NEXAFS and XPS Investigation

E Bernes1 D Toffoli1 M Stener1 G Fronzoni1 M de Simone2 M Coreno3 C Grazioli3 A Guarnaccio3 A Santagata3 C Puglia4 and T Zhang4

1Department of Chemical and Pharmaceutical Sciences University of Trieste 34127 Trieste Italy

2IOM-CNR Laboratorio TASC Sincrotrone Trieste I-34149 Trieste Basovizza Italy

3ISM-CNR Potenza and Trieste LD2 Unit Italy

4Department of Physics and Astronomy

Uppsala University Box 516 SE-751 20 Uppsala Sweden

email HYPERLINK mailtoELISABERNESstudentiunitsit

ABSTRACT

Derivatives of dibenzothiophene (DBT) subsituted with diphenylphosphine oxide find promising application in the development of organic light-emitting diodes (OLEDs1) Due to their potential in the development organic devices a detailed investigation of their electronic properties is of fundamental importance In this respect core electron spectroscopies such as Near-Edge X-ray Absorption Fine-Structure (NEXAFS2) and X-ray photoelectron spectroscopy (XPS) are useful tools to investigate the electronic structure of molecules of varying complexity due to the localized nature of the initial excited state Density functional theory (DFT) calculations at the Kohn-Sham and time-dependent DFT of the 28-Bis(diphenylphosphoryl)dibenzo[bd]thiophene (PPT) and of its constituents building blocks were carried out to simulate measured XPS and NEXAFS spectra at the CO K-edges and S P LII ed LIII edges with the aim of obtaining an extensive comprehension of their electronic structure The XPS and NEXAFS measurements were performed at the Gas Phase Photoemission beam line of the Elettra synchrotron in Trieste3 C and O K-edge spectra were simulated at the DFT level by using the transition potential method while S and P LII ed LIII edges were calculated at the TDDFT level within the ZORA approximation4 The very good agreement between theory and experimental data permits an unambiguous assignment of the spectra and provides a detailed picture of the electronic structure of this important class of systems

REFERENCES

1 S H Jeong and J Y Lee J Mater Chem 21 (2011) 14604-14609 D Kim S Salman V Coropceanu E Salomon A B Padmaperuma L S Sapochak A Kahn and J-L Bredas J Chem Mater 22 (2010) 247-254

2 J Stoumlhr NEXAFS Spectroscopy Springer-Verlag 1992

3 K C Prince R R Blyth R Delaunay M Zitnik J Krempasky J Slezak R Camilloni L Avaldi M Coreno G Stefani C Furlani M de Simone S Stranges J Sync Rad 5 (1998) 565 4 F Wang T Ziegler E van Lenthe S van Gisberger and E J Baerends J Chem Phys 122 (2005) 204103

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 43: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P4

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 44: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P5

Seeking new materials for singlet fission covalent dimers as an alternative to molecular crystals

Davide Accomasso Giovanni Granucci Maria Bruna Stella Maurizio Persico

Department of Chemistry and Industrial Chemistry University of Pisa Italy HYPERLINK mailtodavideaccomassodcciunipiit

ABSTRACT

Singlet fission is a process in which a chromophore A in an excited singlet state (S1) transfers part of its excitation energy to a neighbouring chromophore B in the ground state (S0) and both are

converted into triplet excited states (T1)1 2

A(S1) + B(S0) rarr A(T1) + B(T1) The process represents an opportunity to improve the solar energy conversion efficiency in photovoltaic devices In fact a sensitizer capable of quantitative singlet fission may generate two charge carrier pairs per absorbed photon in a semiconductor material The efficiency of singlet fission depends on the interaction between the two chromophores which in turn is highly sensitive to their relative orientation The difficulty in engineering molecular crystals with favourable interchromophore electronic coupling motivated the idea of intramolecular singlet fission ie to have the process occur within a molecule consisting of two covalently linked chromophore units In covalent dimers the geometry and strength of interchromophore coupling can be tuned through chemical synthesis with an high degree of control difficult to achieve in crystals of monomers Moreover for applications of singlet fission in photovoltaics covalent dimers offer potential practical implementations in fact they can be adsorbed on the surface of a semiconductor material as individual units We propose here a computational protocol to design new covalent dimers for singlet fission and to test their suitability The procedure includes the following steps (i) search for new candidate singlet fission chromophores by designing small molecules and computing the excitation energies for their low-lying electronic states (ii) identification of the most favorable dimeric geometries for singlet fission by evaluating the electronic coupling between the initial cmiddot(S1S0) + cmiddot(S0S1) and final 1(T1T1) state of the process (iii) selection of a way to covalently connect two molecules of the candidate chromophore so as to tune their relative orientation (iv) simulation of the excited state dynamics for the covalent dimer first in vacuum and then adsorbed on a semiconductor material

using a trajectory surface hopping approach3

The excited state dynamics simulation is particularly important not only to determine the singlet fission quantum yield but also to identify competing processes and other deficiencies of the

selected chromophore4

REFERENCES 1 M B Smith and J Michl Singlet fission Chem Rev 1106891ndash6936 2010 2 M B Smith and J Michl Recent advances in singlet fission Annu Rev Phys Chem 64361ndash386 2013

3 G Granucci M Persico and A Toniolo Direct semiclassical simulation of photochemical processes with semiempirical wave functions J Chem Phys 114(24)10608ndash10615 2001

4 D Accomasso G Granucci R W A Havenith M Persico Testing new chromophores for singlet fission a computational protocol applied to 23-diamino-14-benzoquinone Chem Phys Submitted

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 45: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P6

Proton transfer mechanisms in protic ionic liquids

Henry Adenusi1 Enrico Bodo1

1 Chemistry Department University of Rome ldquoLa Sapienzardquo Italy HYPERLINK mailtohenryadenusiuniroma1it

ABSTRACT

In the emerging field of ionic liquids (ILs) a class of compounds known as protic ionic liquids (PILs)

have received increased interest due to their physicochemical properties A key benefit of PILs

stems from their anhydrous proton conductivity PILs are generally synthesized using equimolar

amounts of a Broumlnsted acid and a Broumlnsted base Proton transfer from the acid to the base forms

proton donor and acceptor sites leading to the formation of hydrogen bond networks This class of

ILs possess low vapour pressure low flammability high thermal and electrochemical stability 1 It is

these properties which make them ideal candidates for use in electrochemical applications Further

investigation of the ionic transport behaviour of PILs is essential for the design of electrochemical

devices with improved performance and safety 2

Currently it is not fully understood how molecular modifications contribute to macroscopic proton

diffusion nor how this impacts the bulk electrical properties of the PIL In this study cationic and

anionic moieties are under investigation to understand proton transfer mechanisms in PILs

Candidate PIL structures for superionic proton diffusion have been generated by the addition of

amphoteric substituents on the side chains of typical aprotic ionic liquids (AILs) These side chains

equipped with a protic function should facilitate proton diffusion potentially in a Grotthuss type

mechanism

Recent studies within our group 3 4 have shown specific substituents on anionic moieties in PILs

can develop complex patterns of hydrogen bond interactions Proton transfer via intra and

intermolecular processes have been observed in amino acid ILs

Figure 1 Candidate cation (imidazolium based) and anion (dicyanamide) which have displayed

proton exchange between cation-anion and cation-cation

Imidazolium cations (Figure 1) represent one of the major cationic counterparts used in PILs thus

they have been modified to allow the formation of hydrogen bonding networks to enable high

conductivity mechanisms

REFERENCES

1 Scott T Handy Ionic liquids classes and properties Intech 2011 2 Hiroyuki Ohno Electrochemical aspects of ionic liquids Wiley 2005 3 Andrea Le Donne and Enrico Bodo Journal of Molecular Liquids 249 2018 1075ndash1082 4 M Campetella M Montagna L Gontrani E Scarpellini and E Bodo Physical Chemistry Chemical Physics 2017 19 11869

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 46: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P7

CRYSPLOT a new tool to visualize physical and chemical properties of crystalline solids

Giorgia Beata12 Gianpaolo Perego2 Bartolomeo Civalleri 1

1 Dipartimento di Chimica Universitagrave di Torino Via Giuria 7 I-10125 Torino Italy 2 Aethia Srl Via Ribes 5 10010 Colleretto Giacosa (TO) Italy

giorgiabeataaethiacom

ABSTRACT

Visualization tools are becoming more and more important to analyze help in understanding and present scientific data [1] Here we present a new visualization tool dubbed as CRYSPLOT [2]

Fig 1 Screenshot of the CRYSPLOT web page Fig 2 Example of a combine band structure and DOSs plot

CRYSPLOT is an online web-oriented tool ( HYPERLINK httpcrysplotcrystalsolutionseu

Fig 1) to visualize computed properties of periodic systems It is targeted for plotting properties of crystalline solids as computed with the CRYSTAL code [34] In particular the list of available properties to be plotted is band structure and density of states (DOSs) (see Fig 2) crystal orbital overlap population and crystal orbital Hamiltonian population electron charge density maps profiles and differences electrostatic potential maps Compton profiles and autocorrelation function Simulated infrared Raman and reflectance spectra phonon band structure and density of states Baderrsquos topological analysis functions (eg electron density Laplacian hellip) Transport properties as electron conductivity Seebeck coefficient and electron thermal conductivity Along with plotting CRYSPLOT also permits the modification and customization of plots to meet the standards required for scientific graphics

CRYSPLOT has been designed with advanced and freely available graphical Javascript libraries namely Plotly [5] The programming language used for CRYSPLOT is Javascript Our code parses the input files checks if the uploaded files are correct and if they are it reads the data and organizes them into objects ready to be plotted with plotlyjs library It is modular and flexible so that it is very simple to add other input data formats

Overall CRYSPLOT is a modern and flexible online tool that makes CRYSTAL more users friendly It is totally free easy to use and accessible to users from all over the world through its web page [2]

REFERENCES

1 M Valle ―Visualization A Cognition Amplifier Int J Quant Chem 113 (2013) 2040ndash2052 2 G Beata G Perego B Civalleri in preparation Web page HYPERLINK httpcrysplotcrystalsolutionseu 3 R Dovesi A Erba R Orlando C M Zicovich-Wilson B Civalleri L Maschio M Rerat S Casassa J Baima S Salustro B

Kirtman ―Quantum‐Mechanical Condensed Matter Simulations with CRYSTAL WIREs Comput Mol Sci e1360 (2018) 4 R Dovesi V R Saunders C Roetti R Orlando C M Zicovich-Wilson F Pascale B Civalleri K Doll N M Harrison I J Bush P

DrsquoArco M Llunell M Causagrave Y Noeumll L Maschio A Erba M Rerat S Casassa ―CRYSTAL17 Users Manual (University of Torino Torino 2017)

5 Plotly Technologies Inc Collaborative data science Montreacuteal QC 2015 httpsplotly

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 47: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P8

Molecular dynamics simulations of zinc proteins a new force field

Marco Pagliai1 Marina Macchiagodena1 Claudia Andreini12 Piero Procacci1 Gianni Cardini1

1 Dipartimento di Chimica ldquoUgo Schiffrdquo Universitagrave degli Studi di Firenze via della Lastruccia 3 50019 Sesto Fiorentino (FI) Italy

2 Centro di Ricerca di Risonanze Magnetiche Universitagrave degli Studi di Firenze via L Sacconi 6 50019 Sesto Fiorentino (FI) Italy

marcopagliaiunifiit

ABSTRACT

Zinc is one of the most abundant metal ions in proteins Zinc binding sites can be described through 3D models called Minimal Functional Sites (MFSs) composed of the metal ion(s) the ligands and all those residues that fall within 5 Aring from at least one metal ligand and can thus influence the metal properties and function [1] It has been shown that zinc MFSs can be grouped into 10 clusters which share a similar local structural arrangement

Classical molecular dynamics simulations are one of the computational methods usually applied to study structural and dynamic properties of metalloproteins [2] The reliability of the simulations is related to the accuracy of the force field (FF) in describing the metalprotein interactions

A new computational procedure has been developed to optimize a series of FF parameters for metalloproteins This procedure relies on ab initio calculations in the framework of density functional theory (DFT) which have been carried out with the CP2K suite of programs [3] Molecular dynamics simulations with a new FF have been performed on a series of C2H2-type zinc finger proteins providing results in agreement with experiments

REFERENCES

1 C Andreini I Bertini G Cavallaro PLoS One 6 2011 e26325 2 L Banci Curr Opin Chem Biol 7 2003 143-149 3 J Hutter M Iannuzzi F Schiffman J VandeVondele WIREs Comput Mol Sci 4 2014 15-25

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 48: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P9

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 49: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P10

Unveiling the role of structural features in Na insertion mechanism at anatase surfaces new insights for Na-ion

batteries development

Arianna Massaro1 Ana B Muntildeoz-Garcigravea2 and Michele Pavone1

1 Department of Chemical Science University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples Italy 2 Department of Physics ldquoEttore Pancinirdquo University of Naples ldquoFederico IIrdquo via Cintia 21 80126 Naples

Italy HYPERLINK mailtoariannamassarouninait

ABSTRACT

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs) for large-scale grid energy storage applications [1 2] Despite similar working principles different component materials especially negative electrodes that can accommodate the larger sodium ions must be employed in NIBs [3 4] Recently TiO2 emerged as a promising negative electrode material in both LIBs and NIBs thanks to its inherent safety structural stability and low cost [5 6] Morphological features of TiO2 seem to be crucial and so the fine tuning of crystal phases exposed surfaces nanostructures size and shape is one of the most exploited research heading in this field The tuning of the nanostructures shape can be driven toward the exposition of selected surfaces Thus it is essential to understand how sodium atoms interact and migrate into the lattice in order to address the synthesis toward the highest-efficiency nanomaterial

To this end we propose a theoretical investigation of the Na-insertion mechanism through three different TiO2 surfaces We investigate the Na-insertion process through (101) (100) and (001) surfaces of TiO2 anatase by means of first-principles calculations We show that (001) surface is more active toward Na-insertion showing the lowest migration barrier due to the structural features of the lattice We also model the process upon second Na-insertion in order to give predictions on the long-term stability of each exposed surface

REFERENCES

1 Scrosati B Garche J Lithium batteries Status prospectus and future J Power Sources 2010 195 2419-30 2 Larcher D Tarascon JM Towards greener and more sustainable batteries for electrical energy storage Nature Chem 2015 7 19-29 3 Wang LP Yu L Wang X Srinivasan M Xu ZJ Recent developments in electrode materials for sodium-ion batteries J Mater Chem

A 2015 3 9353-78 4 Dai Z Mani U Teng Tan H Yan Q Advanced Cathode Materials for Sodium-Ion Batteries What Determines Our Choices Small

Methods 2017 1 1700098-124 5 Bella F Muntildeoz-Garcigravea AB Meligrana G Lamberti A Destro M Pavone M Gerbaldi C Unveiling the controversial mechanism of

reversible Na storage in TiO2 nanotube arrays Amorphous versus anatase TiO2 Nano Res 2017 10(8) 2891-903 6 Longoni G Pena Cabrera RL Polizzi S DrsquoArienzo M Mari CM Cui Y Ruffo R Shape-Controlled TiO2 Nanocrystals for Na-ion

Battery Electrodes The Role of Different Exposed Crystal Facets on the Electrochemical Properties Nano Lett 2017 17 992-1000

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 50: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P11

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

De novo protein design represents an attractive challenge in which both structure and function are built from scratch Indeed these enzyme-like catalysts could play a pivotal role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] At this purpose the catalytic mechanism of the engineered Cys-His-Glu triads was explored by means of Molecular Dynamic simulation (MDs) molecular recognition and hybrid QMMM approaches Starting from the X-ray crystallographic coordinates of the apo-form of the heptameric coiled coil deposited in the Protein Data Bank (PDB5EZC) [4] we submitted 100 ns of MDs by using AMBER16 [5] Based on the structural knowledge molecular docking of the p-nitrophenyl acetate (pNPA) to de novo proteins was carried out by using AutoDock42 [6] and 10 poses for ligand were generated for each structure After choosing the best pose we submitted 100 ns of MDs and we selected ten representative complexes with the same protocol above mentioned According to theoretical binding affinity and geometrical filters we selected the best complex in order to elucidate the catalytic mechanism by using Hybrid QMMM applying ONIOM algorithm

Our structural and thermodynamic analysis on this properly functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015) 4 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 5 Case DA Cheatham TE III Darden T Gohlke H Luo R Merz KM Jr Onufriev A Simmerling C Wang B and Woods

R The Amber biomolecular simulation programs J Computat Chem 26 1668-1688 (2005) 6 Morris G M Huey R Lindstrom W Sanner MF Belew RK Goodsell DS and Olson AJ Autodock4 and AutoDockTools4

automated docking with selective receptor flexibility J Computat Chem 16 2785-91 (2009)

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 51: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P12

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 52: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P13

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 53: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P14

De novo proteins Insights from the theoretical investigations

Tiziana Marino Mario Prejanograve Isabella Romeo Nino Russo Dipartimento di Chimica e Tecnologie Chimiche Universitagrave della Calabria Rende I-87036 Italy

email tizianamarino65unicalit

ABSTRACT

The design of de novo proteins in which both structure and function are built from scratch represents a notable challenge These enzyme-like catalysts could play a crucial role for manipulating and obtaining small molecules with prospective applications in medicine and industrial biotechnology [1] Recently this goal was achieved with the installation of the esterase activity into an entirely de novo designed homo-heptameric peptide assembly (CC-Hept) [23] In particular an artificial esterase was obtained by introduction of a catalytic triad consisting of a

glutamate a histidine and a cysteine into each -helix (CC-Hept-Cys-His-Glu) Deeper insights on the conformational behaviour and on the enzymatic activity of this properly

functionalized de novo protein could provide precious information helpful to stimulate new rationally engineered enzymes into a de novo protein framework for both already known and novel chemical transformations

At this purpose in the present study conformational properties of the CC-Hept-Cys-His-Glu engineered hydrolase were explored by means of Molecular Dynamics simulations (MDs) and molecular recognition techniques while the proposed catalytic mechanism was investigated by using a hybrid QMMM approach

REFERENCES

1 Nanda V amp Koder RL Designing artificial enzymes by intuition and computation Nature Chem 2 15-24 (2010) 2 Burton AJ Thomson AR Dawson WD Brady RL amp Woolfson DN Installing hydrolytic activity into a completely de novo

protein framework Nat Chem 8 837-844 (2016) 3 Woolfson D N Bartlett G J Burton A J Heal J W Niitsu A Thomson A R Wood C W De novo protein design how do

we expand into the universe of possible protein structures Curr Opin Struct Biol 33 16-26 (2015)

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 54: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P15

Theoretical Modelling of the Energetic and Vibrational

Properties of Photosynthesis Catalytic Cycle

Matteo Capone1

D Narzi2 L Guidoni

1

1 Universitagrave dellrsquoAquila Italia 2 Egravecole Polytechnique Fegravedegraverale de Lausanne Switzerland

Matteocaponegraduateunivaqit

ABSTRACT

The reaction centre of the Photosystem-II named Oxygen Evolving Complex is a fundamental catalyst for most of the earth life indeed is widely studied as inspiration for artificial mimic structures whom could achieve similar catalytic properties

An extensive and deepen comprehension of peculiar traits of the reaction centre is crucial for such task eventually leading to a large agreement between the all experimental data present nowadays

The crucial steps in the mechanism for oxygen evolution which is composed of 5 states named S0 to S4 resides in the supplying of substrate water molecules (S2S4) and in the bond formation between such substrate oxygens (S4)

Those phases have been studied since decades using several types of spectroscopy and since the first high resolution crystallographic structure [1] with theoretical methods

Using QMMM dynamics and gas phase models we built a comprehensive pathway of intermediate steps starting from the S2 state up to the O-O bond formation [2-58] which involves interconversions between open and closed cubane isomers and the binding of a water molecule to the cluster

With different energy calculation approach we estimated the thermodynamic of such path to clarify a possible preferential reaction way for the molecular oxygen evolution

Furthermore after the characterization of the Mn-core vibrational modes in the S2 state isomers by Vibrational Density Of State of QMMM dynamics [6] in order advance into the interpretation of the experimental infrared data available for the metastable S1 S2 and S3 states [7] we calculated vibrational properties from QMMM dynamics through dipole-dipole autocorrelation function and also using static models with Normal Mode Analysis

In particular to help the interpretation of the experimental data in the middle and low-frequency region (1800-1100 and 700-400 cm-1) we propose a decomposition of the dipole calculated with QMMM-MD The Mn4CaO5 moiety is separated in to diamonds each one involving four atoms and the cluster-ligands in single ligand dipole

The spectral signatures arising from this analysis promise to be a useful insight to assign experimentally identified bands to specific molecular motions

REFERENCES

1 Umena et al Nature 2011 473 55--60 2 Bovi D Narzi D Guidoni L Angew Chem Int Ed 2013 52 11744ndash11749 3 Narzi D Bovi D Guidoni L Proc Natl Acad Sci USA 2014 111 8723ndash8728 4 Capone M Bovi D Narzi D Guidoni L Biochemistry 2015 54 (42) pp 6439ndash6442 5 Capone M Narzi D Bovi D Guidoni L J Phys Chem Lett 2016 7 (3) pp 592ndash596 6 Bovi D Capone M Narzi D Guidoni L Biochim Biophys Acta 2016 1857(10) 1669-1677 7 Debus R J Biochim Biophys Acta 2015 1847(1) 19-34 8 Narzi D Capone M Bovi D amp Guidoni L Chem Eur J 2018 DOI 101002chem201801709

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 55: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P16

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 56: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P17

Excitonic State evolution of DNA Stacked Thymines Different Decay Paths Account for Ultrafast and Longer

(gt100 ps) Deactivations

Irene Contia Marco Garavelli a

a Dipartimento di Chimica Industriale ldquo Toso Montanarirdquo Universita  di Bologna Viale del Risorgimento 4 I-40136

Bologna Italy email Irenecontiuniboit

ABSTRACT

The exciton decay paths for two stacked quantum mechanical thymines inside a solvated DNA duplex described at the

molecular mechanics level are mapped using a hybrid CASPT2CASSCFMM protocol that accounts for steric

electronic and electrostatic interactions within the nucleobases native environment Asymmetric stacking between

nucleobases causes differences in the classical ππ monomer-like ring puckering decay paths accounting for distinctive

excited state lifetimes spanning the sub-ps to sub-ns time window1

Feasible base-pair CT states and their related electronminus proton transfer decay paths could also play a role in the

excited-state wide-ranging lifetimes leading to rare tautomers formations accounting for mispairing and possibly at

the origin of DNA mutations2

REFERENCES

1 I Conti e M Garavelli Evolution of the Excitonic State of DNA Stacked Thymines Intrabase ππrarrS0 Decay Paths Account for Ultrafast (Subpicosecond) and Longer (gt100 ps) Deactivations laquoTHE JOURNAL OF PHYSICAL CHEMISTRY LETTERraquo 2018 9 (9) pp 2373ndash2379

2 Isaac J Kimsey et al Dynamic basis for dGbulldT misincorporation via tautomerization and ionization laquoNATUREraquo 2018 554 pp 195

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 57: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P18

Ionic Liquids and Proton Transfer A Computational Study to Understand Dynamic Processes

Andrea Le Donne1 Enrico Bodo1

1 Chemistry department University of Rome ldquoLa Sapienzardquo Rome Italy andrealedonneuniroma1it

9 ABSTRACT

Ionic Liquids (IL) are pure ionic compounds liquid under room conditions The combination of their liquid state and complete ionization gives them interesting and particular characteristics negligible vapor pressure excellent chemical and thermal stability and the possibility of tuning their physical proprieties adding different chemical groups to the molecular ions1 The presence of strong Coulomb interactions between the ionic pairs makes these kind of materials extremely viscous so that the conductivity of pure IL is low because the drift of ions is hindered by the electrostatic interactions

We are studying the possibility to improve conductivity of IL bypassing the slow drift of ions by exploiting proton transfer (PT) between anions2 We chose a specific subset of IL consisting of choline and anionic amino acids In particular we focused on amino acids with a second acid group on the side chain this is fundamental because the proton of carboxylic group is ―consumed during the synthesis

First of all extensive and accurate ab initio calculations were performed in order to find the best candidate for proton transfer3 The criteria for the selection of candidates were having small energy barriers and near resonant PT reactions where the energies between reagents and products across the PT should be as similar as possible In this way PT should be a dynamic process with the possibility of the proton to migrate into the liquid

Based on upon criteria four candidates have been chosen to be studied by extensive ab initio molecular dynamics and to explore their dynamic properties with particular attention on the mobility of proton

REFERENCES

1 Rogers RD and Seddon KR ―Ionic LiquidsmdashSolvents of the future Science 302 (5646) 792-793 (2003) 2 Campetella M Montagna M Gontrani L Scarpellini E and Bodo E ―Unexpected proton mobility in the bulk phase of cholinium-

based ionic liquids new insights from theoretical calculations Phys Chem Chem Phys 19 (19) 11869-11880 (2017) 3 Le Donne A and Bodo E ―Isomerization patterns and proton transfer in ionic liquids constituents as probeb by ab-initio computetion

J Mol Liq 249 1075-1082 (2018)

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 58: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P19

Simulating 2D IR-UV pump-probe

spectra by means of time-independent

vibronic calculations

Franco Egidi1 Vincenzo Barone 1

1 Scuola Normale Superiore 56126 Pisa Italy

francoegidisnsit

ABSTRACT

In some pump-probe experiments an Infra-Red (IR) pump pulse causes a vibrational transition from the ground vibrational state to an excited vibrational state The frequency of the pump pulse can be tuned to select only certain vibrational modes [12] The pump pulse is followed by a probe which lies in the Ultra-Violet or visible (UV-vis) part of the spectrum thus causing an electronic transition within the system Theoretically electronic transitions are often modeled by considering the effect of the radiation on the electronic degrees of freedom only and the resulting absorption (or emission) spectrum is composed of discrete peaks which can be broadened by means of a given lineshape function (often Gaussian or Lorentzian) with an empirical broadening This approximation however neglects the important contributions from the vibrational degrees of freedom of the molecule which constitute the vibronic signature of the spectrum and in a one-photon UV absorption spectrum can often be the main source of the bandsrsquo broadening and specific bandshape which is often not symmetric In pump-probe experiments vibronic effects cannot be neglected as the experiment highlights precisely the differences in the vibrational manifolds of the ground and excited electronic potential energy surfaces (PES) which can be appreciated in the difference-spectrum obtained small differences in vibrational energies can result in positive and negative peaks We present a method for simulating such experiments by means of time-independent vibronic calculations that fully take the differences in the PESs into account [2] and show results for transition metal complexes which were previously studied experimentally

REFERENCES

1 TL Courtney et al J Phys Chem Lett 6 (2015) 1286 2 TAA Oliver et al Proc Natl Acad Sci USA 111 (2014) 10061 3 J Bloino et al Int J Quantum Chem 116 (2016) 1543

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 59: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P20

Rapid evaluation of dynamic disorder in organic semiconductors

Alessandro Landi1 Andrea Peluso1 Alessandro Troisi2

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Chemistry University of Liverpool Liverpool L69 3BX United Kingdom alelandi1unisait

ABSTRACT

Organic molecular semiconductors are currently widely used in modern optoelectronic devices [1] such as organic light emitting diodes bulk heterojunction solar cells and field effect transistors Research towards the discovery of better semiconductors ie those showing higher charge mobility is very active and many authors are advocating the use of computer-aided materials discovery [2] to accelerate progresses in this field

Unfortunately while for inorganic covalently bonded materials the band theory is well established there is still a debate about the most appropriate theoretical approach to model charge transport in organic semiconductors Indeed it has been pointed out that possibly neither the hopping nor the band-like mechanism is adequate for treating charge transport for the class of high-mobility molecular semiconductors ndash ie those displaying mobilities exceeding 1 cm2 Vminus1 sminus1 [3]

Several alternative models based on the observation that the transfer integral undergoes large fluctuations because of thermal motions also known as dynamic disorder have been developed In particular Fratini et al proposed a method based on the evaluation of a transient localization [4] that when applied to a family of realistic semiconductors demonstrated excellent predictive power

The dynamic disorder is due to the strong modulation of the transfer integral by low frequency molecular phonons ie it is a manifestation of the non-local electron-phonon coupling a property that is computationally expensive to evaluate and so far prevented the study of this property on large datasets of molecules Here we describe a methodology for the fast evaluation of the dynamic electronic disorder for molecular semiconductors starting from their crystalline structure [5] The computation is accelerated by (i) the evaluation of the Cartesian gradient of transfer integral and (ii) the use of approximate phonons evaluated within the rigid body approximation where each molecule is assumed to oscillate independently with the great advantage of separating effectively the internal (intramolecular vibrations) and external (intermolecular vibrations) degrees of freedom Despite the severe approximations our method leads to results in excellent agreement with data obtained with more accurate approaches [6]

REFERENCES

1 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey and J-L Breacutedas Chem Rev 107 926-952 (2007) 2 A V Akimov and O V Prezhdo Chem Rev 115 5797ndash5890 (2015) 3 S Fratini S Ciuchi D Mayou G T De Laissardiegravere and A Troisi Nat Mater 16 998ndash1002 (2017) 4 S Ciuchi and S Fratini Phys Rev B 86 245201 (2012) 5 A Landi and A Troisi under review 6 R S Saacutenchez-Carrera P Paramonov G M Day V Coropceanu and J L Breacutedas J Am Chem Soc 132 14437ndash14446 (2010)

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

P22

P23

Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

P24

P25

P26

Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

P27

Page 60: DCTC 2018 QUINTA EDIZIONE · Marco Garavelli Dipartimento di Chimica ... F. Cappelluti Università degli 6WXG GHOO’ATXL - L’ATXLOD F-RESP: a fast and accurate polarizable force

P21

Hole Mobility in Organic Semiconductors A Second-Order Cumulant Approach

Alessandro Landi1 Raffaele Borrelli2 Andrea Peluso1

1 Dipartimento di Chimica e Biologia Adolfo Zambelli Universitagrave di Salerno Via Giovanni Paolo II I-84084 Fisciano (SA) Italy

2 Department of Agricultural Forestry and Food Science University of Torino Via Leonardo da Vinci 44 I-10095 Grugliasco Italia

alelandi1unisait

ABSTRACT

Charge transport in molecular systems is of paramount importance both for understanding important biochemical processes [1] such as photosynthesis respiration and DNA oxidative damage and for designing new molecular materials for modern optoelectronic devices [2] In the case of molecular semiconductors one of the key properties to be compared with experimental data is the hole mobility and in particular its anisotropy ie the dependence of charge mobility on the orientation of the conductive channel relative to the crystallographic axes

The computational methodology for predicting charge mobility must be related to a mechanism of charge transport in the framework of a simple hopping mechanism hole mobility can be evaluated by a master equation approach with rate constants which are usually obtained either by Marcusrsquo semiclassical approach or by the Fermi Golden Rule (FGR) Both methods suffer from limitations since the former does not account for tunnelling effects and the latter a full quantum mechanical approach at the first order of time dependent perturbation theory is not well suited for ultrafast processes because of the use of the integral representation of the delta function

Herein we use a recently developed approach based on the second-order cumulant (SOC) expansion of the reduced density matrix [3] for evaluating hole hopping rates [4] in homodimers of some of the most studied organic semiconducting molecules It is shown that the SOC approach predicts populations decay in good agreement with those predicted by the numerical solution of the time dependent Schroumldinger equation [5] and leads to anisotropic mobility in good agreement with experimental results even for ultra-fast transitions where FGR fails Moreover the temperature dependence of hole mobility predicted by SOC approach is in line with experimental findings while Marcusrsquo formula leads to wrong temperature dependence [6]

REFERENCES

1 J C Genereux J K Barton Chem Rev 110 1642-1662 (2010) 2 V Coropceanu J Cornil D A da Silva Filho Y Olivier R Silbey J-L Breacutedas Chem Rev 107 926-952 (2007) 3 R Borrelli A Peluso J Chem Theory Comput 11 415-422 (2015) 4 A Landi R Borrelli A Capobianco A Velardo A Peluso J Chem Theory Comput 14 1594minus1601 (2018) 5 Borrelli Capobianco Landi Peluso Phys Chem Chem Phys 17 30937-30945 (2015) 6 A Landi and A Peluso manuscript in preparation

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Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

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Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

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Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

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Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

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Theoretical Study on the Circular Dichroism of Chiral Bimetallic Clusters Ag-Au

Marco Medves1 Mauro Stener1 Giovanna Fronzoni1 Daniele Toffoli1 Alessandro Fortunelli2 Luca Sementa2

1 DSCF Universitagrave di Trieste 2 CNR-ICCOM Pisa

email marcomedvesvirgilioit

ABSTRACT

The POLTDDFT algorithm [1] recently implemented within ADF has been employed to calculate photoabsorption and CD of silver-gold bimetallic chiral clusters The POLTDDFT has proven very efficient to treat accurately large systems without symmetry In particular the optical properties of the cluster [Ag24Au(BINAS)4(DMBT)10]

- have been studied in detail A preliminary optimization identified two structures of comparable energies which were both considered for the study of the optical properties The calculated spectra have been analysed in terms of a recent scheme based on fragments [2] and specific spectral feature have been studied in terms of Individual Component Mapping (ICM) [3] for both oscillator strength and rotation strength Collective behaviours as well as constructivedescructive interference effects have been identified The dichroic response of the cluster has proven very sensitive to the ligand conformations this suggests further studies in order to include ligand conformational freedom in the computational model

REFERENCES

1 Oscar Baseggio Giovanna Fronzoni and Mauro Stener J Chem Phys 143 (2015) 024106 2 Luca Sementa Giovanni Barcaro Oscar Baseggio Martina De Vetta Amala Dass Edoardo Apragrave Mauro Stener Alessandro

Fortunelli J Phys Chem C 121 (2017) 10832 ndash 10842 3 Le Chang Oscar Baseggio Luca Sementa Daojian Cheng Giovanna Fronzoni Daniele Toffoli Edoardo Apragrave Mauro Stener and

Alessandro Fortunelli Journal of Chemical Theory and Computation 14 (2018) 3703

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Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

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Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

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Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

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Combined Orbital-spaceReal-space Analysis of Chemical Bonding through Virtual Reality

Andrea Salvadori1 Marco Fusegrave1 Giordano Mancini1 Sergio Rampino1 Vincenzo Barone1

1 SMART Laboratory Scuola Normale Superiore Piazza dei Cavalieri 7 56126 Pisa sergiorampinosnsit

ABSTRACT

Based on state-of-the-art virtual-reality technology and a recently devised combined orbital-spacereal-space scheme for the analysis of the electron-charge rearrangement occurring upon bond formation we have developed a virtual laboratory for immersive analysis of chemical bonding1 The analysis scheme which couples the natural orbitals for chemical valence (NOCV)2 with a suitably defined integration in physical space3 is capable of singling out chemically meaningful bond components along with quantitative estimates of the related charge-flow profiles and has been recently extended to the four-component fully relativistic framework4 The potential of the developed machinery and the robustness of the analysis scheme will be illustrated through applications including probing the chemical character of superheavy elements5 and investigating the relation between the σ-donorπ-acceptor abilities of ligands and selected spectroscopic observables in coordination complexes6-8

REFERENCES

1 A Salvadori M Fusegrave G Mancini S Rampino V Barone J Comput Chem 2018 in press 2 A Michalak M Mitoraj T Ziegler J Phys Chem A 2008 112 1933-1939 3 G Bistoni S Rampino F Tarantelli L Belpassi J Chem Phys 2015 142 084112 (9pp) 4 M De Santis S Rampino HM Quiney L Belpassi L Storchi J Chem Theory Comput 2018 14 1286-1296 5 S Rampino L Storchi L Belpassi J Chem Phys 2015 143 024307 (8 pp) 6 G Bistoni S Rampino N Scafuri G Ciancaleoni D Zuccaccia L Belpassi F Tarantelli Chem Sci 2016 7 1174-1184 7 M Fusegrave I Rimoldi E Cesarotti S Rampino V Barone Phys Chem Chem Phys 2017 19 9028-9038 8 M Fusegrave I Rimoldi G Facchetti S Rampino V Barone Chem Commun 2018 54 2397-2400

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