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Barriers to rotation about CN bonds—I: Rotation about the CN bond in mono-, di- and trifluoroacetamide, and deuterium isotope effects upon 19F shielding

✍ Scribed by M. H. Pendlebury; L. Phillips


Publisher
John Wiley and Sons
Year
1972
Tongue
English
Weight
398 KB
Volume
4
Category
Article
ISSN
0749-1581

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✦ Synopsis


Abstract

The ^19^F NMR spectra of mono‐ and difluoroacetamide are used to derive the activation parameters for rotation about the CN bond; it is not possible to obtain useful results for trifluoroacetamide. A total line shape analysis is used.

Unusually large deuterium isotope effects upon the shielding of the ^19^F nucleus are observed for N‐deuterated derivatives. The magnitude of the isotope effect is different for mono‐, di‐ and trifluoroacetamides, and in the mono‐deuterated species the isotope effect is different for cis and trans rotational isomers.