Catalytic oxidation of hydrocarbons by trinuclear μ-oxo-bridged ruthenium-acetate clusters: Radical versus non-radical mechanisms

The [Ru3O(H3CCO2)6(py)2(L)]PF6 clusters, where L = methanol or dimethyl sulfoxide, can be activated by peroxide or oxygen donor species, such as tert-butyl hydroperoxide (TBHP) or iodosylbenzene (PhIO), respectively, generating reactive intermediates of the type [RuIV,IV,III3double bond; length as m-dashO]+. In this way, they catalyse the oxidation of cyclohexane or cyclohexene by TBHP and PhIO, via oxygen atom transfer, rather than by the alternative oxygen radical mechanism characteristic of this type of complexes. In addition to their ability to perform efficient olefin epoxydation catalysis, these clusters also promote the cleavage of the Csingle bondH bond in hydrocarbons, resembling the oxidation catalysis by metal porphyrins.