Unexpected Formation of NHC-Stabilized Hydrosilylyne Complexes via Alkane Elimination from NHC-Stabilized Hydrido(alkylsilylene) Complexes

摘要

N-heterocydic carbene (NHC)-stabilized hydrosilylyne complex Cp~*(CO)_2WSiH(~(Me)IMe)_2 (3a) (~(Me)IMe = 1,3,4,5-tetramethylimidazole-2-ylidene) was formed by the reaction of an NHC-stabilized silylene complex Cp~*(CO)_2(H)WSiH(~(Me)IMe){C(SiMe_3)_3} (2a) with 1 equiv of ~(Me)IMe at 70 ℃. In this reaction, HC(SiMe_3)_3 was unexpectedly eliminated from 2a. A C_5Me_4Et analogue of 3a, (C_5Me_4Et)(CO)_2WSiH(~(Me)IMe)_2 (3b), was also synthesized by the same method, and the structure of 3b was confirmed by X-ray crystallography. Although the silicon center of 3b is coordinated by two NHCs, the length of the W-Si bond of 3b [2.363(4) A] is as short as that of the shortest W=Si double bond (~2.36 A). These complexes, 3a and 3b, are the first examples of a base-stabilized silylyne complex having only a hydrogen on the silicon atom.