ISSN:
0749-1581
Keywords:
Long range heteronuclear chemical shift correlation pulse sequence
;
Repression of one bond modulations Heteronuclear 2D NMR
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A modified long-range heteronuclear chemical shift correlation pulse sequence which eliminates modulations of response intensity due to one-bond proton-carbon [1 J(CH)] spin couplings is described. The ‘decoupling’ of one-bond modulation has been accomplished through the use of a bilinear rotational decoupling (BIRD) pulse of the type 90° x(1H)-τ-180° x(1H)/180° x(13C)-τ-90° -x(1H) midway through the second magnetization transfer delay, Δ2.One-bond modulation of response intensities over a range of optimization values is demonstrated for the simple alkaloid norharmane when long-range optimization of the conventional heteronuclear chemical shift correlation pulse sequence is employed. The modified pulse sequence described eliminates one-bond modulations over the same range of optimization values. Slower modulations which arise due to long-range couplings other than that optimized for are present in both experiments.Removal of the effects of one-bond modulation represents a potentially significant improvement in the utility of long-range heteronuclear chemical shift correlation experiments as a tool in spectral assignments and structure elucidation.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260250903
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