A carbonyl osmium (0) complex with π-coordinated olefin,(2, 3-η-1, 4-diphenylbut-2-en-1, 4- dione) undecacarbonyl triangulotriosmium (1), efficiently catalyzes oxygenation of alkanes (cyclohexane, cyclooctane, n-heptane, isooctane, etc.) with hydrogen peroxide, as well as with tert-butyl hydroperoxide and meta-chloroperoxybenzoic acid in acetonitrile solution. Alkanes are oxidized to corresponding alcohols, ketones (aldehydes) and alkyl ...