Binuclear Cage-Like Copper(II) Silsesquioxane (Cooling Tower) - Its High Catalytic Activity in the Oxidation of Benzene and Alcohols

A new method of metallasilsesquioxane synthesis is described for the first time. According to this method, a partial nucleophilic cleavage of polymeric copper phenylsilsesquioxane by the use of sym-cis-tetraphenylcyclotetrasiloxanolate nonaethanolate (1) gave previously unknown binuclear cage-like copper silsesquioxane [(PhSiO1.5)(10)(CuO)(2)(NaO0.5)(2)4EtOH] (2). The unprecedented structure of 2, the so called Cooling Tower structure, was confirmed by single-crystal X-ray diffraction analysis. Compound 2 was found to be an excellent catalyst in oxidation reactions of benzene and alcohols with peroxides in acetonitrile solution at 50-70 degrees C.