The photochemistry of dinuclear osmium carbonyl complexes; characterisation of Os 2(CO) 8 using matrix isolation

Abstract

UV photolysis of Os 2(CO) 9 or ((μ-C1,C2)CH 2CH 2)Os 2(CO) 8 ( 1) isolated in argon matrices causes ejection of a CO or C 2H 4 ligand respectively, and formation of Os 2(CO) 8, which has a structure with only terminal CO groups. Long wavelength irradiation of matrix isolated Os 2(CO) 8 in the presence of potential 2 electron donor ligands leads to production of Os 2(CO) 8L (L = CO, N 2 or C 2H 4), each containing a bridging CO group and a terminally bound ligand L. Photolysis using plane polarised light provides confirmation of the C 2 v structure of Os 2(CO) 9, and gives evidence favouring a D 2 h structure for Os 2(CO) 8. Prolonged UV photolysis of Os 2(CO) 9 in CO matrices leads to cleavage of the OsOs bond and production of Os(CO) 5.