Enhanced nucleophilicity of tris-(2,6-dimethoxyphenyl)bismuthane as studied by X-ray crystallography, 17O NMR spectroscopy and theoretical calculations. X-Ray molecular structure of tris-(2,6-dimethoxyphenyl)bismuthane and of trimesitylbismuthane

Abstract

In marked contrast to previously studied triarylbismuthanes, tris-(2,6-dimethoxyphenyl)bismuthane 1f showed itself to be a nucleophile strong enough to react with some activated alkyl halides via the probable formation of a bismuthonium intermediate. On the basis of X-ray crystallographic and ¹⁷O NMR studies, as well as theoretical considerations, the origin of this uniqueness has been attributed to the through-space interaction between the bismuth centre and neighbouring oxygen atoms working favourably toward the stabilization of the bismuthonium intermediate.