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Steric effects in 29Si and 13C n.m.r. spectra of trimethylsiloxy-substituted benzenes

✍ Scribed by J. Schraml; V. Chvalovský; H. Jancke; G. Engelhardt

Publisher
John Wiley and Sons
Year
1977
Tongue
English
Weight
171 KB
Volume
9
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

^29^Si and ^13^C NMR spectra of trimethylphenoxysilane and three bis(trimethylsiloxy)benzenes have been investigated. Crowding in the ortho derivative leads to a small but observable deshielding of both silicon and carbon nuclei of the trimethylsiloxy group. In comparison to analogous effects observed in trimethylsilyl‐substituted benzenes the oxygen link appears to increase the susceptibility of silicon to this steric effect but to decrease that of the methyl carbons. It is suggested that the operative steric interaction might not be that between the terminal methyl groups but involves the oxygen atom.

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