Elimination of direct responses and one‐bond modulations in long‐range heteronuclear chemical shift correlation spectra through the use of low‐passJfilters and BIRD pulses
作者:
Miguel Salazar,
Andrew S. Zektzer,
Gary E. Martin,
期刊:
Magnetic Resonance in Chemistry
(WILEY Available online 1988)
卷期:
Volume 26,
issue 1
页码: 28-32
ISSN:0749-1581
年代: 1988
DOI:10.1002/mrc.1260260108
出版商: John Wiley&Sons, Ltd.
关键词: two‐dimensional;NMR;2D‐NMR;long‐range heteronuclear chemical shift correlation;bilinear rotational decoupling;BIRD pulses;low‐passJfiltering
数据来源: WILEY
摘要:
AbstractModified long‐range heteronuclear chemical shift correlation pulse sequences which incorporate both BIRD pulses midway through the Δ2magnetization transfer delay and low‐passJfilters 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‐passJfilters 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 Δ2and the two new pulse sequences described in this work are compared using 2,3‐dihydrofuran as a model compound.The low‐passJfilters 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 the3J(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‐passJfilter when compared with the simpler pulse sequence containing only t
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