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Studies of the π‐electron distribution in push–pull alkenes by 1 H and 13 C NMR spectroscopy—II
Author(s) -
Kleinpeter E.,
Thomas St.,
Uhlig G.,
Rudorf W.D.
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.1260310805
Subject(s) - chemistry , thioether , nuclear magnetic resonance spectroscopy , spectroscopy , pulse sequence , carbon 13 nmr satellite , carbon 13 nmr , nmr spectra database , crystallography , spectral line , stereochemistry , analytical chemistry (journal) , fluorine 19 nmr , nuclear magnetic resonance , organic chemistry , physics , quantum mechanics , astronomy
A wide variety of push–pull alkenes were studied by means of variable‐temperature 1 H and 13 C NMR spectroscopy with respect to the configuration/conformation and the barriers to rotation about partial CC and CN double bonds. For the assignment of the 13 C NMR spectra especially the semi‐selective INEPT pulse sequence and an incremental system for estimating the 13 C chemical shift values of aromatic carbon atoms proved useful. The influence of thioether, sulphone and sulphoxide moieties in the acceptor part of the push–pull system on the π‐electron distribution is critically considered.