NHC-Stabilized Silicon–Carbon Mixed Cumulene

The NHC-stabilized
silicon–carbon mixed cumulene (Me3Si)2CSi­(IPr)Si­(IPr)C­(SiMe3)2 (3, IPr = 1,3-diisopropyl-4,5-dimethyl-imidazol-2-ylidene)
has been prepared by reaction of Ar­(SiMe3)­NK with the NHC-stabilized
silene (Me3Si)2CSi­(SiMe3)­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) Å. DFT calculations disclosed its zwitterionic
character. Reaction of 3 with diphenylacetylene resulted
in the formation of a silatriafulvene with an exocyclic NHC-stabilized
silene moiety.