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Basic MQ-MAS
User Manual Version 002
BRUKER BIOSPIN
227 (327)
We see that a 5Q experiment has a 5 times smaller range than the 3Q experiment
and therefore, folding of peaks will always occur even at fast spinning. For even
higher quantum orders the shift ranges are 7 and 30 times smaller for 7Q and 9Q
than for the 3Q experiment, respectively.
summarizes ppm ranges for
the maximum spinning frequencies of 2.5, 3.2, and 4 mm probes, respectively. A
Larmor frequency of 100 MHz is assumed. One can see that the ranges become
less than the typical chemical shift range for many nuclei. The expression
⎜
R-p
⎜
acts like a scaling factor that scales the frequency scale directly. Mathemat-
ically this is solved in the AU program
xfshear
in such a way that the observe Lar-
mor frequency is multiplied by the factor Á
R-p
Á to redefine an apparent Larmor
frequency in the MQ dimension.
Figures are calculated for a Larmor frequency of 100 MHz.
From the isotropic shift and the shift position in the MQ dimension the so-called
SOQE
parameter can be calculated,
d
qis
being given by equation 2:
(Eq. 17.4)
with
(Eq. 17.5)
f(I)
equals 4, 16.67, 39.2, and 72 for I=3/2, 5/2, 7/2, and 9/2, respectively. So one
can see that for a given value of
Q
cc
the second order quadrupole induced upfield
shift
d
qis
decreases as the spin
I
increases. With
d
qis
always being negative this
has a direct influence on the appearance of the sheared 2D spectra.
shows 2D
17
O 3QMAS spectra at 11.7 T and 18.8 T where the Lar-
mor frequency of this nucleus is 67.8 and 108.4 MHz, respectively. The sample is
Table 17.6.
Chemical Shift Ranges for all MQ Experiments for All Spins I
Spin
I
and MQ
Experiment
15 kHz
[4 mm probe]
25 kHz
[3.2 mm probe]
35 kHz
[2.5 mm probe]
3/2
39.6 ppm
66.0 ppm
92.4 ppm
5/2 3Q
5/2 5Q
105.6 ppm
26.1 ppm
176.0 ppm
35.2 ppm
246.4 ppm
49.3 ppm
7/2 3Q
7/2 5Q
7/2 7Q
197.4 ppm
39.5 ppm
14.1 ppm
329.0 ppm
65.8 ppm
23.5 ppm
460.6 ppm
92.1 ppm
32.9 ppm
9/2 3Q
9/2 5Q
9/2 7Q
9/2 9Q
319.2 ppm
63.2 ppm
45.6 ppm
10.6 ppm
532.0 ppm
160.4 ppm
76.0 ppm
17.7 ppm
744.8 ppm
144.9 ppm
106.4 ppm
24.8 ppm
( )
5
2
0
2
2
10
3
1
ω
δ
η
I
f
Q
SOQE
qis
cc
=
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
+
=
( )
(
)
(
)
(
)
(
)
3
1
4
3
1
2
4
2
−
+
−
−
=
I
I
I
I
I
f
Содержание Solid State NMR
Страница 1: ...Version Bruker BioSpin think forward NMR Spectroscopy Solid State NMR 002 AVANCE Solids User Manual...
Страница 8: ...8 BRUKER BIOSPIN User Manual Version 002 Contents...
Страница 14: ...14 327 BRUKER BIOSPIN User Manual Version 002 Test Samples...
Страница 104: ...104 327 BRUKER BIOSPIN User Manual Version 002 Practical CP MAS Spectroscopy on Spin 1 2 Nuclei...
Страница 118: ...118 327 BRUKER BIOSPIN User Manual Version 002 Basic CP MAS Experiments...
Страница 122: ...122 327 BRUKER BIOSPIN User Manual Version 002 FSLG HETCOR Figure 8 3 The ased Display...
Страница 154: ...154 327 BRUKER BIOSPIN User Manual Version 002 Proton Driven Spin Diffusion PDSD...
Страница 172: ...172 327 BRUKER BIOSPIN User Manual Version 002 SUPER Figure 13 3 The Acquisition Parameter Window eda...
Страница 178: ...178 327 BRUKER BIOSPIN User Manual Version 002 SUPER...
Страница 192: ...192 327 BRUKER BIOSPIN User Manual Version 002 Symmetry Based Recoupling...
Страница 212: ...212 327 BRUKER BIOSPIN User Manual Version 002 Relaxation Measurements...
Страница 270: ...270 327 BRUKER BIOSPIN User Manual Version 002 Double CP...
Страница 284: ...284 327 BRUKER BIOSPIN User Manual Version 002 CRAMPS 1D Figure 22 9 WPMLG CRAMPS After Optimization Digital Acquisition...
Страница 290: ...290 327 BRUKER BIOSPIN User Manual Version 002 Modified W PMLG...
Страница 302: ...302 327 BRUKER BIOSPIN User Manual Version 002 CRAMPS 2D...
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Страница 318: ...318 327 BRUKER BIOSPIN User Manual Version 002 Tables...
Страница 326: ...326 327 BRUKER BIOSPIN User Manual Version 002 Index...
Страница 327: ...User Manual Version 002 BRUKER BIOSPIN 327 327 End of Document...