Density functional study of the mechanism of halophilic reactions of some silylenes

The hybrid density functional B3LYP method has been used to study the mechanism of disilane formation from silylenes. The main findings can be summarized as follows: (a) Lewis acid–base complexes between silylenes and halocarbons only play a limited role in silylene insertions, and therefore the acid–base complex mechanism proposed by West et al. does not apply to disilane formation. (b) Regardless of whether transient or stable, all silylenes follow the energetically favorable general reaction pathway: (I) Y2Si:+ClCR3 → TS1 → Y2ClSi–CR3. (II) Y2Si:+Y2ClSi–CR3 → TS2 → Y2ClSi–SiY2CR3.