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An NMR study of some N-arylaminopropenylylidenearylammonium salts

✍ Scribed by C. P. Richards; G. A. Webb

Publisher
John Wiley and Sons
Year
1975
Tongue
English
Weight
316 KB
Volume
7
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

The preparation, characterisation and ^1^H NMR spectra of some N‐arylaminopropenylylidenearylammonium salts are reported. The NMR data show that in DMSO the cations exist as conjugated amino–imines, generally as the ‘all‐trans’ geometrical isomer. An exception is found in the case of the 4‐nitrophenyl derivative which produces a mixture of the ‘all‐trans’ and ‘cis‐trans’ isomers with slow exchange between them at room temperature. The relative stability of the ‘all‐trans’ isomer increases as the salt becomes more ionic. By varying the temperature, pH and nature of the anion it is found that exchange of the NH protons on the cation controls the appearance of spin‐spin coupling between the NH and 1,3‐propene protons.

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