Reactions of an Isolable Dialkylsilylene with Carbon Dioxide and Related Heterocumulenes

Abstract

An isolable dicoordinate dialkylsilylene, 2,2,5,5-tetrakis­(trimethylsilyl)­silacyclopentane-1,1-diyl (<b>6</b>), was found to react with CO₂ and ArNCX (X = O, S) smoothly to give the corresponding bis­(silyl)­carbonate, 4-imino-1,3-dioxasiletane and 4-imino-1,3-dithiasiletane derivatives in high yields, respectively. The molecular structures of these products were determined by X-ray crystallography. All these reactions are parallel to those of a hypercoordinate silylene with η⁵-pentamethylcyclopentadienyl ligands, decamethylsilicocene, reported by Jutzi et al. and are suggested to involve similarly the formation of the corresponding SiX doubly bonded compounds (X = O, S) at the initial steps. Mechanistic details of the multistep reaction of a model dialkylsilylene with CO₂ were investigated using DFT calculations