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Spectroscopy
Volume 12, Issue 1, Pages 25-29
http://dx.doi.org/10.1155/1994/123819

The unexpectedly low sensitivity of the nitrogen NMR shieldings of covalent azides to solvent effects

M. Witanowski,1 W. Sicinska,1 and G. A. Webb2

1Institute of Organic Chemistry, Polish Academy of Science, 01-224 Warsaw, Poland
2Department of Chemistry, University of Surrey, Guildford, Surrey, UK

Copyright © 1994 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The nitrogen shieldings of covalent azides are shown to be essentially independent of molecular interactions in solutions of a large variety of solvents. They present a rare case where substituent effects, exerted by an aryl or alkyl group attached to the azide, clearly swpass the range of solvent induced effects on the nitrogen shieldings. This occurs in spite of the large net change splitting in the electronic structure of the azide group and the presence of lone pair electrons on this group. The observed induced range of solvent effects does not exceed 2 ppm in most cases which is similar to that previously observed for dinitrogen (N2) and an azo bridged structure.