THE PHOTOCHEMISTRY OF DINUCLEAR OSMIUM CARBONYL-COMPLEXES - CHARACTERIZATION OF OS2(CO)8 USING MATRIX-ISOLATION

UV photolysis of Os2(CO)9 or ((μ-C1,C2)CH2CH2)Os2(CO)8 (1) isolated in argon matrices causes ejection of a CO or C2H4 ligand respectively, and formation of Os2(CO)8, which has a structure with only terminal CO groups. Long wavelength irradiation of matrix isolated Os2(CO)8 in the presence of potential 2 electron donor ligands leads to production of Os2(CO)8L (L = CO, N2 or C2H4), each containing a bridging CO group and a terminally bound ligand L. Photolysis using plane polarised light provides confirmation of the C2v structure of Os2(CO)9, and gives evidence favouring a D2h structure for Os2(CO)8. Prolonged UV photolysis of Os2(CO)9 in CO matrices leads to cleavage of the OsOs bond and production of Os(CO)5. © 1990.