CARBONYL-ETA-HEXAMETHYLBENZENE COMPLEXES OF OSMIUM - CARBON-HYDROGEN ACTIVATION BY (ETA-C6ME6)OS(CO)(H)2

Reduction of (η-C6Me6)Os(CO)Cl2 (1) with zinc/acetic acid/methanol gives (η-C6Me6)Os(CO)(Cl)H (2), which can be further reduced with Na[H2Al(OCH2- CH2OCH3)2] to (η-C6Me6)Os(CO)H2 (3). Photolysis of 3 in hydrocarbons (benzene, cyclohexane, neopentane) results in formation of the carbon-hydrogen bond activation products (η-C6Me6Os(CO)(R)(H) (6a-6c, R = C6H5, C6H11 and CH2C(CH3)3, respectively) and free hexamethylbenzene. Independent syntheses of the hydrides 6a-6c are described as well as syntheses of the complexes (η-C6Me6)Os(CO)(R)2 (4a-4c) and (η-C6Me6)Os(CO)(R)Cl (5a-5c). The structure of (η-C6Me6)Os(CO)(cyclohexyl)2 (4b) determined by single crystal X-ray diffraction is reported. © 1990.