THERMAL DEGRADATION OF DIMETHYLVINYLARSINE IN TRIOSMIUM CLUSTERS TO GIVE BRIDGING VINYL, VINYLIDENE, AND ACETYLENE LIGANDS

From the thermal decarbonylation of [Os3(CO)11{AsMe2(CHCH2)}] in refluxing hydrocarbon solvents the new clusters [Os3(CO)10(CHCH2)(AsMe2)], [Os3H(CO)9(CCH2)(AsMe2)], and [Os3H(CO)9(CHCH)(AsMe2)] have been isolated and shown to be formed successively. The isomerisation of the µ3-vinylidene to the µ3-acetylene complex is the first example of this. Structures and dynamic behaviour are discussed mainly on the basis of 1H n.m.r. data.