1

Structural characterization of inorganic aluminosilicate systems:

role of water

(4)(4)

+1

+3+2

0−1−2−3

t1 τ90°-sel.

+1

+3+2

0−1−2−3

t1 τ90°-sel.

Introduction – ss-NMR of inorganic systemsNMR crystallographyProblem of quadrupolar nucleiRemoving of quadrupolar broadening (DOR, MQ/MAS)Enhancement of spectral resolution

Structure of aluminosilicate systemsAmorphous aluminosilicate inorganic polymers (AIP) – synthesisPrimary structural data about Al/Si materials – 29Si a 27Al MAS NMRAmorphous-crystalline phase transition of AIPsHow to get structural parameters

29Si, 27Al, 23Na MAS NMR 27Al MQ/MAS NMR 1H MAS NMR and spin relaxation29Si CP/MAS a REDOR NMR (localization of H2O)VA-CT 29Si CP/MAS (hydration extent)1H-1H MAS (interaction network)27Al REDOR MQ/MAS NMRStructural model

Outlook

Is NMR spectroscopy really such unique method?

Magnetic Resonance Imaging

Concept of NMR crystallography

NMR crystallography

ss-NMR Spectroscopy

Molecular Modeling

X-ray (Powder) Diffraction

structural fragments

process of structure refinement1H-1H spin-exchange1H-13C contacts1H-15N distances

motional frequencies

motional amplitudes

chemical shifts

etc.

diffraction pattern

pair distribution function analysis

etc.

conformation (DFT)

prediction of long-range arrangement

NMR parameters (CASTEP)

etc.

Refined structure with incorporated segmental dynamics, intermolecular

interaction and supramoleculararchitecture

Applications

Finding relations between molecular structure, and physicochemical properties (bioavailability) of…

… pharmaceuticals based on solid solution and solid dispersions of API in polymer matrix,

NMR active nuclei – problem of inorganic systems; I>1/2

22 spins I=1/277 spins I=3/2, 5/2,9/2

1 spin I=1

Spin 1/2 Spin 3/2

m=1/2

m=-1/2

m=-1/2

m=1/2

m=3/2

m=-3/2

Spectrum: narrow signal 0,1-100 Hz

Spectrum: broad signal 1000-100000 Hz

( ) ( )

( ) ( )3cos30cos358

1cos

1cos32

1cos

244

22

+−=

−=

θθθ

θθ

P

P

= 0

=−7/18

θ = 54.74°MAS narrows 2nd order broadening

only by a factor 3 to 4

Quadrupolar broadening

= 0

=−7/18

θ = 54.74°

= 0

=−7/18

θ = 54.74°

2

( ) ( )

( ) ( )3cos30cos358

1cos

1cos32

1cos

244

22

+−=

−=

θθθ

θθ

P

P

= 0

=−7/18

θ = 54.74°

Quadrupolar broadening and MAS (off-MAS)

17O DAS crystobalit

DAS: Dynamic Angle Spinning

( ) ( )

( ) ( )3cos30cos358

1cos

1cos32

1cos

244

22

+−=

−=

θθθ

θθ

P

P

23Na DOR of sodium oxalate

DOR: Double Rotation

+1

+3+2

0−−−−1−−−−2−−−−3

evolution mixing

MQSQ ST SQ CT

z-filter“whole echo”

t1 ττττ

90°-sel.

CT

+1

+3+2

0−−−−1−−−−2−−−−3

evolution mixing

MQSQ ST SQ CT

z-filter“whole echo”

t1 ττττ

90°-sel.

CT

ppm

-200 ppm15

10

5

0

ppm

20 0 ppm15

10

5

0

23Na MQ/MAS Na2HPO4.H2O

Multiple-quantum NMR spectroscopy

ppm

-40-30-20-1020 10 0 ppm

-25

-20

-15

-10

-5

35

30

25

20

15

10

5

0

SQ

TQ

A1, A4

A3

A2

xx

Kyanite, z-filtered experiment at 11.7 T

anisotropic traces

traces for A1 and A4 cannot be resolved

27 kHz MAS frequency

250 kHz RF

excitation pulse: 1.9 µs

conversion pulse: 0.7 µs

90° selective pulse: 11 µs

Al-27 3Q MAS traces of Kyanite at different fields

50 40 30 20 ppm 20 10 ppm40 30 20 10 ppm

9.4 T 11.7 T 18.8 T

1.0 1.0 1.0 0.8 1.0 0.8 0.7 1.02.0Int:

27Al 3Q MAS of Kyanite at different fields

Multiple-quantum NMR spectroscopy

ppm

-2020 0 ppm15

10

5

0

23Na MQ/MAS

Form III

-20-100 ppm

-2040 20 0 ppm

23Na MAS NMR

31P MAS NMR

MQ/MAS NMR spectroscopy – polymorphism of ATP

3

-50 -100 ppm

80 60 40 20 ppm

27Al

29Si

Fly ash-slag-metakaoiline

80 60 40 20 ppm

-50 -100 ppm

27Al

29Si

CSH gel

80 60 40 20 ppm

-50 -100 ppm

Typical aluminosilicateinrognic polymer (AIP)

27Al

29Si

ppm

ppm -50 -100 ppm

80 60 40 20 ppm

Zeolite system

27Al

29Si

27Al

29Si

80 60 40 20 ppm

-50 -100 ppm

Slightly crystalline AIP system

Variability of Al/Si materials Synthesis of AIP systems

Kaolin650°C Metakaolin

Al4(OH)8Si4O10

1. Calcination

activation @ RT

Primary units2.Activation

Si2O5.Al2O2

MetakaolinSi2O5.Al2O2 + 5H2O+2NaOH

Si

OH

OHOH

OH

Si

OH

OHOH

OHAl

-

OH

OHOH

OH Na+

Al-

OH

OHOH

OH Na+

polycondensation @ RT

Primary building units

3. Polycondensation

Si

OH

OHOH

OH

Si

OH

OHOH

OHAl

-

OH

OHOH

OH Na+

Al-

OH

OHOH

OH Na+ Si

OH

OO

OH

Al-

OH

OOH

Si

OHO

OH

Al-

OHOH

Na+

Na+

OH2

OH2

OH2

OH2

-4H2O

Amorphous network

Geopolymers and NMR, Davidovits: Geopolymers (1994)

29Si MAS NMR

Structure of AIP systems

Q4(4Al)

Q4(3Al) Q4(2Al)

Q4(1Al)

Q4(0Al)

SiO4 AlO4

Q4(4Al)

Q4(0Al)

Q4(3Al)

Q4(1Al)

a)

b)

100 50 0 ppm

Al (IV)

Al (V) Al (VI)

Simple calcination:formation of metakaoline

7days @ RT&

1day @ 140°C; HT

27Al MAS NMR

Al (V) ssb

-100-50 ppm

1day @ RT

7days @ RT

177day @ RT

7days @ RT&

1day @ 100°C; HT

Q4(0Al)

Q4(1Al)

Q4(2Al)

Q4(4Al)

Q4(3Al)

Q0/Q1

(OH)

29Si MAS NMR

Calcination with NaOH: formation of geopolymer precursor

Hyd

roth

erm

al tr

eatm

ent

Norm

al cu

ring

Calc

ination

Hyd

roth

erm

al tr

eatm

ent

Norm

al cu

ring

Calc

ination

Si-O-

D. Koloušek, J. Brus et al. JOURNAL OF MATERIALS SCIENCE 42 (22): 9267-9275 NOV 2007.

Synthesis of AIP systems

Method A Method B

NT/7 d HT/7 dHT/14 d

HT/21 dHT/28 d

0

10

20

30

40

50

60

70

Str

engh

t, M

Pa

Experimental conditions

Stable

system

Unstable

system

Time dependence of compression strength

(artificial aging)

Stable

system

Unstable

system

Structural instability of AIPs: spontaneous crystallization

Stable system

Unstable system

Basis structural parameters: 29Si,27Al,23Na MAS NMR

Untreated AIPsStable system

Unstable system

4

Basis structural parameters: 29Si,27Al,23Na MAS NMR

Artificially aged AIPsStable system

Unstable system

Basis structural parameters: 27Al MQ/MAS NMR

AIPs before and after accelerated agingStable system

Unstable system

Basis structural parameters : 1H MAS NMR, relaxation

1,00E-03

1,00E-02

1,00E-01

1,00E+00

1,00E-11 1,00E-10 1,00E-09 1,00E-08 1,00E-07 1,00E-06

log(τc), s

log

(T1 )

, s

• •

○ ○

■ ■

□ □

310 K

280 K

System A

System B

A-aged

B-aged

Fast motions Slow motions

AIPs before and after accelerated agingStable system

Unstable system

Hydration of star clusters Q4(nAl)

System A System B

Q4(3Al);22%

Q4(2Al);25%

Q4(1Al);10% Q4(4Al);42%

ppm -140-130-120-110-100-90-80-70-60

A aged B aged

Q4(4Al);34%

Q4(3Al);32%

Q4(2Al);22%

Q4(1Al);12%

ppm -140-130-120-110-100-90-80-70-60

Q4(4Al);33%

Q4(3Al);28%

Q4(2Al);27%

Q4(1Al);8%

ppm -140-130-120-110-100-90-80-70-60

Q3(nAl);4%

Q4(3Al);22%

Q4(2Al);25%

Q4(1Al);10%

Q4(4Al);42%

ppm -140-130-120-110-100-90-80-70-60

Q4(4Al);20%

Q4(3Al);36% Q4(2Al);33%

Q4(1Al);6%

Q4(0Al);5%

ppm-140 -130-120-110-100 -90 -80 -70-60

Q4(4Al);20%

Q4(3Al);26% Q4(2Al);42%

Q4(1Al);7%

Q4(0Al);5%

ppm-140-130 -120 -110 -100-90-80-70-60

Q4(4Al);13%

Q4(3Al);25% Q4(2Al);28% Q4(1Al);27%

Q4(0Al);7%

Q4(1Al);10%

ppm-140 -130 -120 -110-100 -90-80-70-60

Q4(4Al);26%

Q4(0Al);2%

Q4(3Al);30% Q4(2Al);32%

System A System B

A aged B aged

ppm-140-130-120 -110 -100-90-80-70 -60

1H-29Si Cross-Polarization

Decoupling

1H:

90°

CPX:

CP

29Si CP/MAS NMR 29Si REDOR/MAS NMR

Acquisition

29Si-{1H} REDOR dephased

1H:

29Si:

90°

τ

180°

180° 180°

τ τττ τ

nrot

ττ

nrot

Decoupling

Hydrogen-bonding network: H2O/-OH/H+

Acquisitiont2

1H:

90°

τ1

90° 90°

τm

ppm

20 15 10 5 0 ppm

-5

20

15

10

5

0

A aged

ppm

20 15 10 5 0 ppm

-5

20

15

10

5

0

ppm

20 15 10 5 0 ppm

-5

20

15

10

5

0

ppm

20 15 10 5 0 ppm

-5

20

15

10

5

0

B aged

System A System B

1H-1H spin diffusion

Hydration of Al sites: 27Al {1H}-REDOR MQ/MAS NMR

ppm50607080

50

60

70

80

ppm

0

ppm50607080

50

60

70

80

ppm

027Al-{1H} SQ REDOR MQ/MAS

1H:

27Al:

exct conv

180° 180°

nrot nrot

Decoupling

select180°

ppm50607080

50

60

70

80

ppm

0

ppm50607080

50

60

70

80

ppm

0

27Al-{1H} SQ REDOR MQ/MAS

1H:

27Al:

exct conv

180° 180°

nrot nrot

Decoupling

select180°

Stable system

Unstable system

Signals of hydrated units are suppressed

Al sites that are strongly hydrated

5

sdifference no (U)δcs

3 125 70.06ppm(M)δcs

sdifference no (U)δcs

3.16 148 57.39ppm(M)δcs

3.12 143 61.44ppm(U)δcs

3.05 137 63.76ppm(M)δcs

3 131 67.16ppm(U)δcs

3.03 133 65.02ppm(M)δcs

)distance(Α )angle(

TT TOT

)shiftchemical( 2717

2710

)(

4

4

3

3

2

2

1

1

2

=<=

====

<==

°−−−

−+= csppmcs iso δδδδ

Structural model of stable and unstable AIPs

Stable system

Unstable system

Structural model of stable AIPs

Summary

Solid-state NMR and ………….

Quadrupolar interactions

Multiple-quantum MQ/MAS

Double rotations: DOR

Hydration of Al/Si matrix

Synthesis of AIPs – structural stability

Structural models

+1

+3+2

0−−−−1−−−−2−−−−3

evolution mixing

MQSQ ST SQ CT

z-filter“whole echo”

t1 ττττ

90°-sel.

CT

+1

+3+2

0−−−−1−−−−2−−−−3

evolution mixing

MQSQ ST SQ CT

z-filter“whole echo”

t1 ττττ

90°-sel.

CT

ppm50607080

50

60

70

80

ppm

0

27Al-{1H} SQ REDOR MQ/MAS

1H:

27Al:

exct conv

180° 180°

nrot nr ot

Decoupling

select180°

27Al-{1H} SQ REDOR MQ/MAS

1H:

27Al:

exct conv

180° 180°

nrot nr ot

Decoupling

select180°

1,00E-03

1,00E-02

1,00E-01

1,00E+00

1,00E-11 1,00E-10 1,00E-09 1,00E-08 1,00E-07 1,00E-06

log(τc), s

log

(T1),

s

• •

○ ○

■ ■

□ □

310 K

280 K

System A

System B

A-aged

B-aged

Fast motions Slow motions

1,00E-03

1,00E-02

1,00E-01

1,00E+00

1,00E-11 1,00E-10 1,00E-09 1,00E-08 1,00E-07 1,00E-06

log(τc), s

log

(T1),

s

• •

○ ○

■ ■

□ □

310 K

280 K

System A

System B

A-aged

B-aged

Fast motions Slow motions

a.u.

0.00040.00020.0000 sec

0.5

0.0

ppm

20 15 10 5 0 ppm

-5

20

15

10

5

0

Acquisition

29Si-{1H} REDOR dephased

1H:

29Si:

90°

τ

180°

180° 180°

τ τττ τ

nrot

ττnrot

Decoupling

Acquisition

29Si-{1H} REDOR dephased

1H:

29Si:

90°

τ

180°

180° 180°

τ τττ τ

nrot

ττnrot

Decoupling

1H-29Si Cross-Polarization

Decoupling

1H:

90°

CPX:

CP

1H-29Si Cross-Polarization

Decoupling

1H:

90°

CPX:

CP