Trinuclear Osmium Clusters as Models for Intermediates in Carbon Monoxide Reduction Chemistry. 1. Stepwise Reduction of CO to a μ-CH2 Ligand on an Os3 Cluster Face

Article abstract of DOI:10.1021/ja00321a601

Treatment of Os3(CO)12 in tetrahydrofuran (THF) with K at 0 deg C gives an unstable formyl complex K (1).Acidification of THF solutions of 1 with aqueous 20percent H3PO4 yields the new cluster Os3(CO)11(μ-CH2) which has been spectroscopically characterized.Attempted alkylation of 1 with <(CH3)3O>BF4 also gave Os3(CO)11(μ-CH2).Methane is produced when Os3(CO)11(μ-CH2) is heated under an H2 atmosphere, but when the mixture is heated in the absence of H2, CO loss occurs to yield H2Os3(CO)9(μ3-CCO), which has been spectroscopically characterized.The mechanism of the ^- to Os3(CO)11(μ-CH2) transformation is discussed as well as the possible relevance of these results to CO reduction on metal surfaces.