Reactions of (Silyl)(silylene)tungsten and -molybdenum Complexes with Sulfur Reagents

Reaction of (silyl)(silylene)tungsten complex Cp*(OC)2W(SiMe3)(SiMes2) (1) with sulfur reagents, S8 and ethylene sulfide 4, afforded cyclic carbene tungsten complex Cp*(S)W{C(SiMe3)C(O)OSi(Mes)2S} (3) via CO bond fission of a carbonyl ligand and 1,2-migration of the SiMe3 group from W to the resulting carbene carbon. In contrast to the tungsten complex, reaction of (silyl)(silylene)molybdenum complex Cp*(OC)2Mo(SiMe3)(SiMes2) (2) with 4 gave η2-thiocarbonyl complex Cp*(S)Mo[{η2-SC(SiMe3)}C(O)OSi(Mes)2S] (5), which would be formed by addition of a sulfur atom to the MoC bond of a molybdenum analogue of 3.