SiSi Double Bonds: Synthesis of an NHC‐Stabilized Disilavinylidene

An efficient two‐step synthesis of the first NHC‐stabilized disilavinylidene ( Z )‐(SIdipp)SiSi(Br)Tbb ( 2 ; SIdipp=C[N(C 6 H 3 ‐2,6‐ i Pr 2 )CH 2 ] 2 , Tbb=C 6 H 2 ‐2,6‐[CH(SiMe 3 ) 2 ] 2 ‐4‐ t Bu, NHC=N‐heterocyclic carbene) is reported. The first step of the procedure involved a 2:1 reaction of SiBr 2 (SIdipp) with the 1,2‐dibromodisilene ( E )‐Tbb(Br)SiSi(Br)Tbb at 100 °C, which afforded selectively an unprecedented NHC‐stabilized bromo(silyl)silylene, namely SiBr(SiBr 2 Tbb)(SIdipp) ( 1 ). Alternatively, compound 1 could be obtained from the 2:1 reaction of SiBr 2 (SIdipp) with LiTbb at low temperature. 1 was then selectively reduced with C 8 K to give the NHC‐stabilized disilavinylidene 2 . Both low‐valent silicon compounds were comprehensively characterized by X‐ray diffraction analysis, multinuclear NMR spectroscopy, and elemental analyses. Additionally, the electronic structure of 2 was studied by various quantum‐chemical methods.