Advanced NMR spectroscopy of quadrupolar nuclei · 22 spins I= 1/2 77 spins I=3 /2 , 5/2 ,9/2 1...
Transcript of Advanced NMR spectroscopy of quadrupolar nuclei · 22 spins I= 1/2 77 spins I=3 /2 , 5/2 ,9/2 1...
Advanced NMR spectroscopy Advanced NMR spectroscopy
of of quadrupolarquadrupolar nuclei nuclei
AutAuthhoor:r: Libor Libor KoberaKobera
NMR active nuclei – problem of inorganic systems; I>1/2
22 spins I=1/2
77 spins I=3/2, 5/2,9/21 spin I=1
Spectrum: narrow signal
0,1-100 Hz
Spectrum: broad signal
1000-100000 Hz
I=1/2
- /2
m
-1 2
/21
2
I=1/2
- /2
m
-1 2
/21
2
Zeemanova
interakce
I=3/2
3/2
m
1/2
-1/2
-3/2
ν0
ν0
ν0
3Q
Zeemanova
interakce
I=3/2
3/2
m
1/2
-1/2
-3/2
ν0
ν0
ν0
3Q
Quadrupolar broadening
( ) ( )
( ) ( )3cos30cos358
1cos
1cos32
1cos
24
4
2
2
+−=
−=
θθθ
θθ
P
P
= 0
=−7/18
θ = 54.74°MAS narrows 2nd order broadening by
a factor 3 to 4
1st order quadrupolar coupling
2nd order quadrupolar coupling
ν0-νQ1-νSTQ
2
Zeeman
interaction
1st order
quadrupolar
coupling
2nd order
quadrupolar
coupling
I=3/2
3/2
m
1/2
-1/2
-3/2
ν0
ν0
ν0
ν0
ν0-νQ1
ν0+νQ1 ν0+νQ
1+νSTQ2
ν0-νCTQ2
3Q
ν0-νQ1-νSTQ
2
Zeeman
interaction
1st order
quadrupolar
coupling
2nd order
quadrupolar
coupling
I=3/2
3/2
m
1/2
-1/2
-3/2
ν0
ν0
ν0
ν0
ν0-νQ1
ν0+νQ1 ν0+νQ
1+νSTQ2
ν0-νCTQ2
3Q
54.7°
NMR techniques for quadrupolar nuclei DOR/DAS/MQMAS
DOR NMR DAS NMR MQ/MAS NMR
1D spectrum 2D spectrum 2D spectrum
DOR: DOuble Rotation
In practice:
ν0 7-8 kHz
v1 1-2 kHzAdvantages
quantitative
high sensitivity
low rf field requirement
fast 1D experiment
Disadvantages
special and expensive probes
required
low spinning frequency
stable spinning is difficult
Only for crystalline
compounds
23Na Static(top),
MAS(middle),
DOR(bottom)
NMR spectra of sodium oxalate
π/2π/2
ω1
ω2
ω1
ω2
ω1
ω2
ω1
ω2
ω1
ω2
ω1
ω2
Shear
DAS: Dynamic Angle Spinning
Advantages
quantitative
high sensitivity
low rf field requirement
For amorphous compounds
π/2π/2
π/2
Switch
37,38° 79,19°π/2
π/2π/2
Switch
37,38° 79,19°
Disadvantages
special and expensive
probes required
nuclei with long T1
Impossible decoupling
(β1 and β2≠ 54.7°)
MQ/MAS: Multi Quantum Magic Angle Spinning
Avantages
Easy to implement and no
special probe required
Good for abundant nuclei
Good for nuclei with short T1
17O NMR spectra of hydroxyapatite
Disadvantages
Not quantitative
High rf field required for
the excitation pulse
Poor sensivity for large CQ
57.238
49.071
44.480
t1 t2
z-filter
π/227Al
t1 t2
z-filter
π/227Al
ppm-500
01020304050607080ppm
0
0 CS
QIS
ppm-500
01020304050607080ppm
0
0 CSCS
QISQIS
ppm-500
-20-10010203040ppm
0
0
A
CSQIS
ppm-500
-20-10010203040ppm
0
0
AA
CSQIS
Shear
MQ/MAS spectrum - analysis
A
CSQIS
Information about
Number of species
Orderliness
Local geometry
determine of CQ, ηQ by simulation
MQ-MAS NMR spectra exhibit a higher resolutionthan DAS or DOR spectra
Chemical shift
27
1017 cs 21 FF
δδδ
+=
Quadrupolar coupling
constant
6
0
2
10])12(4[
3)1(4
10
3
3121
⋅−
−+⋅=
+=−
=
ν
ηδδ
II
IIk
CPk
PQQ
FF
Q
Amorphous materials –glasses, cements, AIPs etc…
Sodium /
Potasium
H2 0
H 20
H 20
H 20
H20
H 20 H 2
0H 2
0 H 20H2
0H
2 0
H20H
20
H20
H20
H20H
20 H20H20
H20
H20
H20
H2 0
H2 0
H2 0
H2 0
H2 0
H2 0
H20
H20
H20
H20
H 20
H20 H20
H2 0
H20
H 20
H2 0
H2 0
H2 0
H20H20H20H20
aluminum
oxygen
oxygen
Sodium /
Potasium
silicon
Amorphous alumino-silicate polymers AIP`s
Boron glasses
crystalline
amorphous
Preparation and properties of AIP`s
Kaolin650°C
Metakaolin
Al4(OH)8Si4O10
1. Calcination
activation @ RT
Primary units2.Activation
Si2O5.Al2O2
Metakaolin
Si2O5.Al2O2 + 5H2O+2NaOH
Si
OH
OHOH
OH
Si
OH
OHOH
OH
Al-
OH
OHOH
OH Na+
Al-
OH
OHOH
OH Na+
polycondensation @ RT
Primary building units
3. Polycondensation
-4H2O
Amorphous network
Si
OH
OHOH
OH
Si
OH
OHOH
OH
Al-
OH
OHOH
OH Na+
Al-
OH
OHOH
OH Na+
PropertiesProperties
excellent mechanical strength
resistance to high
temperatures
easy recycling
low production of CO2
long-time stability
Q4
(4Al)
Q4
(3 Al)
Q4
(2 Al)
Q4
(1 Al )
Q4
(0 Al)
Si O4
AlO4
Building unitsBuilding units
Si
OH
O
OOH
Al-
OH
OOH
Si
OHO
OH
Al-
OHOH
Na+
Na+
OH
2
OH
2 OH
2
OH 2
Preparation and basic characterization
29Si MAS NMR
0
1
2
3
4
5
ppm-130-120-110-100-90-80-70
ppm-130-120-110-100-90-80-70
0
1
2
3
4
5
Q3(nAl); 2%
Q4(4Al); 28%
Q4(3Al); 35%
Q4(2Al); 22%
Q4(0Al); 8%
Q4(1Al); 5%
Q3(nAl); 1%
Q4(4Al); 27%
Q4(3Al); 36%
Q4(2Al); 22%
Q4(1Al); 5%
Q4(0Al); 9%
ppm01020304050607080
ppm01020304050607080
27Al MAS NMR
Al(IV) Al(IV)
Al(VI) Al(VI)
ppm-40-30-20-10010203040
ppm-40-30-20-10010203040
23Na MAS NMR
stable vs. unstable
Characterization after accelerated aging
ppm-130-120-110-100-90-80-70
0
1
2
3
4
5
Q3(nAl); 3%
Q4(4Al); 23%
Q4(3Al); 27% Q4(2Al); 36%
Q4(1Al); 10%
Q4(0Al); 1%
ppm-130-120-110-100-90-80-70
0
1
3
4
5
Q3(nAl); 11%
Q4(4Al); 16%
Q4(3Al); 30%Q4(2Al); 29%
Q4(1Al); 9%
Q4(0Al); 5%
ppm-130-120-110-100-90-80-70
0
1
2
3
4
5
Q3(nAl); 3%
Q4(4Al); 23%
Q4(3Al); 27% Q4(2Al); 36%
Q4(1Al); 10%
Q4(0Al); 1%
ppm-130-120-110-100-90-80-70
0
1
3
4
5
Q3(nAl); 11%
Q4(4Al); 16%
Q4(3Al); 30%Q4(2Al); 29%
Q4(1Al); 9%
Q4(0Al); 5%
stable vs. unstable
27Al MAS NMR
ppm01020304050607080
ppm01020304050607080
27Al MAS NMR
ppm01020304050607080
ppm01020304050607080
Al(IV)Al(IV)
Al(VI) Al(VI)
23Na MAS NMR
ppm-40-30-20-10010203040 ppm
-40-30-20-10010203040
29Si MAS NMR
23Na MQ/MAS of AIP systems
stable vs. unstableCompression
strength70 MPa
Compression strength70 MPa
Compression strength70 MPa
Compression strength30 MPa
ppm-20-1001020
-20
-10
0
10
20ppm
0
0 CS
A
QIS
ppm-20-1001020
-20
-10
0
10
20ppm
0
0 CS
A
QIS
ppm-20-1001020
-20
-10
0
10
20ppm
0
0 CS
A
QIS
ppm-20-1001020
-20
-10
0
10
20ppm
0
0 CS
A
QIS
27Al MQ/MAS of AIP systems
ppm45.050.055.060.065.070.075.0
50
60
70
80ppm
0
0
A
CSQIS
ppm45.050.055.060.065.070.075.0
50
60
70
80ppm
0
0
A
CSQIS
A
CSQIS
ppm45.050.055.060.065.070.075.0
50
60
70
80ppm
0
0
A
CSQIS
stable vs. unstable
Accelerated aging
Compression strength70 MPa
Compression strength70 MPa
Compression strength70 MPa
Compression strength30 MPa
Al-
O+
O
O
OSi
Si
Si
Si
H
Al-
O+
O
O
OSi
Si
Si
Si
Na
ppm45.050.055.060.065.070.075.0
50
60
70
80ppm
0
0
Al-
O
O
O
O
Si
Si
Si
Si
Al
OHOH
OH
stable vs. unstable
Accelerated aging
1H-1H MAS NMR correlation spectra
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
ppm
20 15 10 5 0 ppm
-5
20
15
10
5
0
Summary
Since 74% of all magnetically active naturally occurring isotopes
are quadrupolar nuclei
Suitable for descriptions of local geometry to long distance
Combination of high magnetic field and 2D MQ/MAS NMR
experiments allow obtaining high-resolution spectra with usual
MAS probe
Possible for all types of materials (crystalline or amorphous)
Thanks for your attention Thanks for your attention