A Class of Computationally Designed Tri-Coordinate Cyclic Silylenes RSi(µ-R)2AlR2

Abstract

With the aim of designing novel low-valent silylenes, herein we report the first systematic investigation of the SiAlR5 system. Based on the ‘topology’ isomeric search strategy, four classes of isomers, i.e. RSi(μ-R)2AlR2 1, R3Si-AlR2 2, R2Si(μ-R)AlR2 3, and R2Si-AlR3 4 were identified. For 12 groups with an electron lone-pair, i.e. R = F, NH2,OH, SH, OMe, PMe2, SMe, OEt, PEt2, SEt, OPh, and PPh2, the tri-coordinate silylene 1 is the most stable structure, which contains two sets of intermolecular donor–acceptor interactions. In accordance with the ‘silylene’ term, the Si-centre can undergo both a nucleophilic reaction and insertion reaction. Moreover, coupling AlR3 (R = OR′ and PR′2) (R′ = H, Me, Et, and Ph) with the known cyclic di-coordinate silylene could lead to stable tri-coordinate silylenes. These novel tri-coordinate silylenes strongly welcome laboratory studies in near future.