Aminofluorsilane: 1.3-Silylgruppenwanderung und gehinderte Si-N-Bindungsrotation / Aminofluorosilanes: 1.3-Migration of Silyl Groups and Si-N-Rotational Barrier

Abstract

Triaminofluorosilanes with bulky amino groups are prepared by the reaction of bis- (organyl-trimethylsilyl)amino-difluorosilanes with lithiated amines. A 1,3-migration of trimethylsilyl groups from bulky alkylamino substituents to arylamino substituents is observed in these reactions. Structural isomers of the new triaminofluorosilanes were isolated. The silyl group migration depends on steric and electronic effects. Further reactions of the triaminofluorosilanes with butyllithium and trifluoroorganylsilanes lead to the formation of difluorosilyl-substituted triaminofluorosilanes and LiF. The symmetric compounds show AB-systems for the fluorine atoms of the difluorosilyl groups in the low temperature 19F NMR Spectra, due to hindered rotation about the Si-N-bond. The coalescence temperature depends on the bulkiness of the substituents and is observed at or about room temperature.