THE PHOTOCHEMISTRY OF (MU-3-ETA-2-CH3CH2C=CCH2CH3)-(MU-CO)OS3(CO)9 AND (MU-H)(MU-3-ETA-3-CH3CH2C=C=C(H)CH3)OS3(CO)9 IN RARE-GAS MATRICES AT 10-K

The photochemistry of (μ3-η2-CH3CH2CCCH2CH3)(μ-CO)Os3(CO)9 (compound I) was studied by FITR spectroscopy at 10 K in argon matrices. Upon irradiation at 480 nm, compound I readily converted to a nonacarbonyl intermediate (compound II), accompanied by the elimination of carbon monoxide. The isomer of II is (μ-H)(μ3-η3-CH3CH2CCC(H)CH3)Os3(CO)9 (compound III). III was not produced upon warming II in the matrix to 50 K. However, a 10 K matrix of III was prepared from a room-temperature sample. Compound III was found to form a new photoproduct (IV) at 10 K, which has a spectrum similar to I. Photolysis of III in the presence of N2, CO or rare gas indicates that the formation of IV does not involve the uptake of a tenth ligand to form the 48-electron species. A possible explanation is the II and IV are 46-electron nonacarbonyl isomers, presumably with the capping organic ligand oriented perpendicular and parallel, respectively, to the metalmetal bond. © 1990.