NHC-Stabilized Silicon-Carbon Mixed Cumulene

摘要

The NHC-stabilized silicon-carbon mixed cumulene (Me_3Si)_2C=Si(IPr)=Si(IPr)=C(SiMe_3)_2 (3, IPr = 1,3-diisopropyl-4,5-dimethyl-imidazol-2-ylidene) has been prepared by reaction of Ar(SiMe_3)NK with the NHC-stabilized silene (Me_3Si)_2C=Si(SiMe_3)Cl(IPr) (2) in toluene at low temperature via the elimination of trimethylsilyl and chloride groups from 2. X-ray crystal analysis of 3 indicated the formal C=Si=Si=C cumulene skeleton with the short Si-Si double bond distance of 2.1896(10) A. DFT calculations disclosed its zwitterionic character. Reaction of 3 with diphenylacety-lene resulted in the formation of a silatriafulvene with an exocyclic NHC-stabilized silene moiety.