Stable Trisilaallene with Formally sp-Hybridized Silicon Atom

摘要

Trisilaallene 1 was synthesized by the reductive dechlorination of a tetrachlorodisilane derived from the reaction of an isolable dialkylsilylene with silicon tetrachloride.In the solid state,trisilaallene skeleton in 1 was not linear but bent with the Si-Si-Si bond angle of 136.46(5)deg.Central formally sp-hybridized silicon atom was found in the four positions with different population depending on temperature.This behavior suggests that the central silicon atom was rotating along the axis through two terminal silicon atoms even in the solid state.Similar unusual dynamic behavior of 1 was also found in solution.The two splitting absorption band feature and the remarkable red shift of the longest band for 1 are consistent with the significant conjugation between the two Si=Si double bonds.