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Unexpected second-order effects in proton-coupled 13C NMR spectra

✍ Scribed by Alan W. Douglas; Michael Shapiro

Publisher
John Wiley and Sons
Year
1980
Tongue
English
Weight
180 KB
Volume
14
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

‘Unexpected’ second‐order effects encountered in proton‐coupled ^13^C NMR spectra where relative proton shifts are large compared to proton‐proton coupling constants are illustrated. The observed phenomenon is explained, with reference to the ABX spin system as a model, as being due to the near equality of the relative proton shift, in frequency units, to the difference between one‐bond and long‐range ^13^CH couplings. The effect may be removed by a change in operating field strength or addition of a shift reagent.

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