From Silylone to an Isolable Monomeric Silicon Disulfide Complex

The synthesis and characterization of the first bis‐N‐heterocyclic carbene stabilized monomeric silicon disulfide (bis‐NHC)SiS 2 2 (bis‐NHC=H 2 C[{NC(H)C(H)N(Dipp)}C:] 2 , Dipp=2,6‐ i Pr 2 C 6 H 3 ) is reported. Compound 2 is prepared in 89 % yield from the reaction of the zero‐valent silicon complex (′silylone′) 1 [(bis‐NHC)Si] with elemental sulfur. Compound 2 can react with GaCl 3 in acetonitrile to give the corresponding (bis‐NHC)Si(S)S→GaCl 3 Lewis acid–base adduct 3 in 91 % yield. Compound 3 is also accessible through the reaction of the unprecedented silylone‐GaCl 3 adduct [(bis‐NHC)Si→GaCl 3 ] 4 with elemental sulfur. Compounds 2 , 3 , and 4 could be isolated and characterized by elemental analyses, HR‐MS, IR, 13 C‐ and 29 Si‐NMR spectroscopy. The structures of 3 and 4 could be determined by single‐crystal X‐ray diffraction analyses. DFT‐derived bonding analyses of 2 and 3 exhibited highly polar SiS bonds with moderate p π –p π bonding character.