Chemistry of low valent silicon

The preparation of NHC center dot SiCl2 and its reaction with various reagents is reported (NHC = N-heterocyclic carbene). A comparable reaction is used for preparing LSiCl from LSiHCl2 and NHC (L = PhC(NtBu)(2)). The reduction of LSiCl results in the formation of the inter-connected bis-silylene of composition LSi: Si:L. The latter compound reacts with P-4 and AdC P to LSiP2SiL and LSi(Ad)CPSiL, respectively. Treatment of NHC center dot SiCl2 with 2,6-Ar2C6H3N3 (Ar = 2,6-iPr(2)C(6)H(3) or 2,4,6-iPr(3)C(6)H(2)) resulted in the NHC center dot(SiCl2)=N2,6-Ar2C6H3. The reduction of the latter yields the bis-silylene. This cyclic bis-silylene of composition (2,6-Ar2C6H3NSi:)(2) contains a four-membered N2Si2 ring with two coordinate silicon. Treatment of LSiN(SiMe3)(2) with P-4 results in the acyclic 6 pi system L((Me3Si)(2)N)Si=P-P=P-P=Si(N(SiMe3)(2))L under opening of the P-4 tetraeder. Metal complexes of silylenes with Co, V, and Ni are reported. (C) 2012 Elsevier B.V. All rights reserved.