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Determination of chemical‐shift tensor orientations in methylene groups by separated‐local‐field NMR
Author(s) -
SchmidtRohr K.,
Wilhelm M.,
Johansson A.,
Spiess H. W.
Publication year - 1993
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.1260310408
Subject(s) - methylene , chemistry , ethylene , polyoxymethylene , nuclear magnetic resonance spectroscopy , tensor (intrinsic definition) , spectroscopy , ethylene oxide , local symmetry , nuclear magnetic resonance , analytical chemistry (journal) , stereochemistry , organic chemistry , polymer , geometry , physics , mathematics , quantum mechanics , copolymer , catalysis
The 13 C chemical‐shift tensor orientations in the OCH 2 CH 2 O moieties of poly(ethylene oxide) (PEO) and poly(ethylene terephthalate) (PET) were determined by means of 1 H 13 C separated‐local‐field NMR spectroscopy, and the literature values for the shift tensors in polyethylene (PE) and polyoxymethylene (POM) were improved. An angular resolution of ± 4° was attained on standard equipment with 90° pulse lengths exceeding 4 μs. Relatively high uniformity of the methylene tensor orientations, complying with local molecular symmetry, was found.