Two generalizable routes to terminal carbido complexes.

Desulfurization of the thiocarbonyl ligand in square pyramidal [Ru(CS)Cl2(PCy3)2] (1-S) via sulfur atom abstraction using [Mo(H)(eta2-Me2CNAr)(N[i-Pr]Ar)2] forms [Ru(C)Cl2(PCy3)2] (1) cleanly over several hours in benzene; isolated yield is 55%. Complex 1 is also formed in 87% isolated yield upon reaction of [Ru(CHR)(PCy3)2Cl2] (R = p-C6H4Me, 2; Ph, 3) with vinyl acetate in dichloromethane. Complex 1-S is re-formed quantitatively from 1 upon treatment with elemental sulfur in CH2Cl2, but is prepared most conveniently by treatment of crude [Ru(CS)Cl2(PPh3)2(OH2)] with excess PCy3 in toluene. Nearly quantitative conversion of 1 to [Ru(CO)Cl2(PCy3)2] (1-O) occurs upon addition of dimethyldioxirane solution in acetone to 1 dissolved in CH2Cl2 at ca. -90 degrees C.