Interconversion between -2,2-C60 and 3-2,2,2-C60 on a Carbido Pentaosmium Cluster Framework

Carbonyl addition or elimination reactions on an Os5C cluster framework result in a novel interconversion between two C60 bonding modes: μ3-η2,η2,η2-C60 for 1 and μ-η2,η2-C60 for 2. The latter bonding mode had been elusive until now, and treatment of 1 with BnNC and subsequent thermolysis provides yet another example, 3. The μ-η2,η2-C60 ligand exhibits two different orientations with respect to the Os3 face in 2 and 3.