The development of new water soluble sensitizers for application in

photo-oxygenation flow synthesis.Jamaal Abubakar

Supervisor Dr. Kieran Nolan

Phalocyanines are a work horse in the dye industry, discovered back in 1907 by accident by Braun and Tcherniac who recorded a highly coloured compound after heating ortho-cyanobenzamide at high temperature.

It was fully structurally characterised by the end of world war one by Reginald and his students, who used different techniques including elemental analysis, ebullioscopic molecular determination and oxidative degradation in order to obtain the structure of phthalocyanine.

Phthalocyanine

And this was proven by Prof J Robertson and co-workers at the Davy Faraday laboratory in 1930 via X-ray diffraction techniques. However, the identification of the components of the mixture was not possible back then. This was made possible by the invention of 1H NMR and 13C NMR.

First prepared metal free phthalocyanine (Pc)

N

HN

NNN

NH

N N

NH2NH2

O

OCN

AcetoneHeat

NH2

O

+

Any transition metal can be put in the centre Radioactive metal if required Pcs typically absorbed in about 620-700nm which is

not bad but the problem with Pcs is they aggregate in solution, so when molecules aggregate their photo physical properties change. They’re not good basically, you kill it.

An important characteristic in organic molecules is that the physical and chemical properties of the molecules can be altered by changing the molecular structure.

substituted and unsubstituted Pc Fluorinated Pcs are highly stable and an excellent

catalyst for photooxygenation.

Enrichment of photo-sensitizer Photo-stability High level of oxygen production Lipophilicity Selective accumulation in tumour cells Photo-dynamic therapy agent As an excellent probe for sensitive and minimally all-

encompassing imaging HOMO & LUMO increases

The presence of fluorine gives the molecule the following properties

(1) Synthesis of 4-butoxy phthalonitrile:

15% yield was obtained with a melting point of 70 - 72oC which is 22oC more than the literature value of 48 - 49oC

NC

NC O

4 butoxy phthalonitrile

CN

CNO2N4-Nitrophthalonitrile

Butanol

DMF and K2CO3

CH3

(2) Synthesis of 4-butoxy-3,5,6-trifluoro-phthalonitrile:

NC

NC O

Butanol

DMF and K2CO3

CN

CNF

F

F

F

Tetrafluorophthalonitrile

F

FF

4-Butoxy-3,5,6-trifluoro-phthalonitrile

CH3

(4-Amino-butyl)-carbamic acid tert-butyl ester Amine (A)

NN

HH

H

O

O C

CH3

CH3

CH3

(3) Synthesis of (2-Amino-ethyl)-carbamic acid tert-butyl ester

H2N

Ethylenediamine Amine (B)MW 60.10g/mol

BOC2OO

O

NH

CNH2

NH2

MW 218.25g/mol

(2-Amino-ethyl)-carbamic acid tert-butyl esterMW 160.214g/mol

C O

O

O

O

C

(4) Synthesis of 4-(3,4-Dicyano-2,5,6-trifluoro-phenylamino)-butyric acid tert-butyl ester:

NH2N

(3-Amino-propyl)-carbamic acid tert-butyl ester Amine (D)MW= 174g/mol

K2CO3

DMF

Tetrafluorophthalonitrile

CN

CN

F

F

F

HN

O

O

4-(3,4-Dicyano-2,5,6-trifluoro-phenylamino)-butyric acid tert-butyl ester

HN

O

O C

CH3

CH3

CH3

H

Flourinated Pc

N

N

N

N

N

N

N

N

M

F

F

FF F

F

F

F

F

F

F

F FF

F

F

Flourinated Pc

Photochemistry

Quenching test

UV-Vis of 4-(3,4-Dicyano-2,5,6-trifluoro-phenylamino)-butyric acid tert-butyl ester with silver nitrite

Tetrafluorophthalonitrile 19F NMR

CN

CN

F

F

F

F

QUESTIONS

Thank You