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6.16 CPNOESYPS—Cross-Polarization Phase-Sensitive NOESY
90°° pulse width are retained. Default parameters set up for a phase-sensitive hypercomplex
acquisition with sw1=sw and xpol='y'.
Parameters
cpcosyps uses UNITYINOVA and UNITYplus parameters tpwr, tpwrm, dpwr, cppwr,
dipolr, crossp, dblvl2, pw, and cntct. See page 63 for a description of these
parameters.
xpol is set to 'n' for preparation by direct polarization; xpol is set to 'y' for
preparation by cross-polarization.
pw is the observe 90° pulse (xpol='n') or the proton 90° pulse (xpol ='y'). pw is in
microseconds.
pwx is the mixing pulse, in microseconds. If xpol='n', pwx=pw; if xpol='y', it is set
to the observe 90° pulse.
srate is the measured MAS spinning speed. CPCOSYPS does not require rotor speed
control. However, with rotor speed control, set sw1 equal to srate to remove spinning
sidebands in both dimensions.
phase=1,2 for the hypercomplex method (use wft2da for the 2D FT); phase=3 for
TPPI (use wft2d(1,0,0,0) for the 2D FT).
Reference
Wu, G.; Wasylishen, R. E. Organometallics 1992, 11, 3242.
6.16 CPNOESYPS—Cross-Polarization Phase-Sensitive
NOESY
The CPNOESYPS sequence is a 3-pulse 2D exchange correlation sequence similar to the
high-resolution NOESY experiment. CPNOESYPS can be run as a direct polarization
experiment or the first 90° pulse can be substituted with a cross-polarization pulse element.
Figure 36 is a diagram of this sequence.
For CPNOESY, cross peaks occur between resonances that share mutual through-space
dipolar coupling or interact through weak spin diffusion. Coupling can be enhanced with
the insertion of rotor synchronized π pulses during the mixing period. Cross peaks are also
observed between resonances with chemical exchange and CPNOESYPS can be used to
observe exchange between static powder spectra. Use XNOESYSYNC to characterize
molecular motion in the presence of MAS.
Applicability
CPNOESYPS, found in userlib, is available only on UNITYINOVA and UNITYplu
Macro
The macro cpnoesyps converts a parameter set, obtained with XPOLAR or XPOLAR1,
for the solids 2D exchange correlation experiment CPNOESYPS. Power levels and the
proton 90° pulse width are retained. Default parameters set up for a phase-sensitive
01-999162-00 A0800
VNMR 6.1C User Guide: Solid-State NMR
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