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Extraction of 1 H 1 H and 1 H 13 C dipolar couplings from spectra acquired in inhomogeneous magnetic fields
Author(s) -
Kay Lewis E.,
Thomson D. S.,
Prestegard J. H.
Publication year - 1988
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260261010
Subject(s) - chemistry , homogeneity (statistics) , pulse sequence , dipole , spectral line , coupling constant , magnetic field , nmr spectra database , j coupling , molecule , liquid crystal , scalar (mathematics) , analytical chemistry (journal) , crystallography , molecular physics , nuclear magnetic resonance , nuclear magnetic resonance spectroscopy , stereochemistry , physics , condensed matter physics , quantum mechanics , chromatography , organic chemistry , statistics , mathematics , geometry
Experimental procedures are presented for the extraction of 1 H 1 H and 1 H 13 C dipolar couplings from molecules oriented in high magnetic fields without a requirement for high field homogeneity. These couplings impose restrictions on structure in a manner similar to NOE distances and can serve as useful additional constraints for defining structure. The experimental procedures involve pulse sequences which refocus the effects of magnetic field inhomogeneities but which retain dipolar couplings, scalar couplings and, in cases of chemically distinct groups, chemical shift differences. The methods are important for the extension of experiments to higher fields and more complex media where field homogeneity is hard to maintain. The experiments are illustrated using samples containing sodium acetate‐99% 13 C 2 or alanine‐99% 13 C 3 dissolved in a nematic liquid crystal and oriented in an inhomogeneous magnetic field. Coupling constants obtained from the studies are in good agreement with couplings extracted from one‐dimensional spectra obtained in homogeneous fields.