ISSN:
0749-1581
Keywords:
two-dimensional
;
NMR
;
2D-NMR
;
long-range heteronuclear chemical shift correlation
;
bilinear rotational decoupling
;
BIRD pulses
;
low-pass J filtering
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Modified long-range heteronuclear chemical shift correlation pulse sequences which incorporate both BIRD pulses midway through the Δ2 magnetization transfer delay and low-pass J filters are described. The BIRD pulse provides the means of decoupling one-bond modulations of response intensity when magnetization is transferred to protonated carbons. The one- and three-step low-pass J filters utilized eliminate responses due to directly attached protons over a range of one-bond coupling constants.Results obtained by long-range optimization of the conventional heteronuclear chemical shift correlation pulse sequence, the previously reported pulse sequence containing only the BIRD pulse midway through Δ2 and the two new pulse sequences described in this work are compared using 2,3-dihydrofuran as a model compound.The low-pass J filters have no adverse effects on the ability of the BIRD pulse to decouple one-bond modulations. Modulation decoupling in the modified pulse sequences was confirmed using the 3J(C-3, H-1) coupling pathway of the simple alkaloid norharmane. The response intensities, however, were up to 10% lower with a one-step low-pass J filter when compared with the simpler pulse sequence containing only the BIRD pulse midway through Δ2.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260260108
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