Tungsten carbonyl sigma-complexes with charge-compensated nido-carboranyl thioether ligands

Charge-compensated nido-carboranyl thioether ligands [7-MeS-10-Me2S-7,8-C2B9H10] and [7,8-(MeS)(2)-10-Me2S-7,8-C2B9H9] were prepared and fully characterized. They readily react with labile tungsten carbonyls to give sigma-complexes - mono-substituted (CO)(5)W[7-MeS-10-Me2S-7,8-C2B9H10-kappa(1)-S(1)] and (CO)(5)W[7,8-(MeS)(2)-10-Me2S-7,8-C2B9H9-kappa(1)-S(1)] and chelate (CO)(4)W[7,8-(MeS)(2)-10-Me2S-7,8-C2B9H9-kappa(2)-S(1), S(2)]. The synthesized metallocomplexes were characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction. The donor ability of the 7-methylsulfide-nido-carborane ligand is not sensitive to introduction of the charge-compensating dimethylsulfonium group.