LIGAND SHIFT IN MIXED-CLUSTER COMPLEXES - SYNTHESIS OF ALKYNE-BRIDGED CO2MO2 CLUSTERS WITH 2 TRIPLY-BRIDGING SULFUR-ATOMS - CRYSTAL-STRUCTURE OF [CO2MO2(ETA-5-CP)2(MU-3-S)2(MU-4-CF3C2ME)(CO)4]

Reaction of the complexes [CO)3Co(mu-RC2R')Co(CO)3] (R = R' = CF3; R = Ph, CF3 and R' = H) with the Mo = Mo dinuclear derivative [Mo2Cp2(mu-SMe)2(CO)2] leads to cleavage of both C-S and C-H bonds with the formation of closo-octahedral Mo2Co2C2 clusters stabilised by a mu-4-eta-2-bound alkyne. An X-ray diffraction study has shown that the two Mo2Co faces of the octahedron are capped by triply-bridging sulphur atoms.