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Spectral analysis of the high‐resolution proton‐coupled carbon‐13 NMR spectra of 1,3,2‐dithiarsolanes
Author(s) -
Aksnes D. W.,
Holak T. A.
Publication year - 1982
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270180107
Subject(s) - geminal , chemistry , conformational isomerism , methylene , vicinal , coupling constant , proton , chemical shift , crystallography , nmr spectra database , substituent , spectral line , stereochemistry , carbon 13 nmr satellite , stereospecificity , nuclear magnetic resonance spectroscopy , molecule , medicinal chemistry , fluorine 19 nmr , organic chemistry , physics , particle physics , quantum mechanics , astronomy , catalysis
The high‐resolution proton‐coupled 13 C NMR spectra of 2‐chloro‐ and 2‐phenyl‐4‐methyl‐1,3,2‐dithiarsolane and 2‐chloro‐ and 2‐phenyl‐1,3,2‐dithiarsolane have been obtained and completely analysed. The spectral analysis has provided all the 13 C chemical shifts and 13 C 1 H coupling constants, including their relative signs. The results of this work are adequately interpreted in terms of two rapidly equilibrating half‐chair conformers with the 4‐methyl pseudo‐axial or pseudo‐equatorial. The cis isomers appear to be conformationally biased towards the form with the 4‐methyl pseudo‐equatorial. The two one‐bond 13 C 1 H coupling constants of the methylene group are distinctly different. For both the cis and trans isomers, the largest one‐bond coupling always involves the methylene proton situated syn to the substituent at arsenic. The observed variation in the geminal and vicinal 13 C 1 H coupling constants are discussed in terms of a stereospecific inductive effect of the sulphur hetero‐atoms and conformational factors.