Chalcogen-atom transfer and exchange reactions of NHC-stabilized heavier silaacylium ions.

Abstract

Heavier analogues of silaacylium ions 2-4 ([m-TerSiE(NHC)2]Cl; m-Ter = 2,6-Mes2C6H3; Mes = 2,4,6-Me3C6H2; 2 (E = S), 3 (E = Se), 4 (E = Te)) were synthesized by the reaction of the NHC-stabilized silyliumylidene cation 1 with elemental chalcogens. Fascinating regeneration of 1 from the reaction of 2-4 with AuI was achieved, as successful recovery of a parent Si(ii) species from a silachalcogen Si(iv) compound. Furthermore, unique chalcogen exchange reactions from 4 → 3 → 2 were observed in line with the calculated silicon-chalcogen bond energies.