NOVEL, DINUCLEAR MECHANISM FOR CATALYTIC OLEFIN DIMERIZATION. PHOTOCHEMICAL REACTIVITY OF ( mu -HYDRIDO)( mu -ALKENYL)DIRHENIUM OCTACARBONYL COMPOUNDS.

Article abstract of DOI:10.1021/ja00324a015

UV photolysis of ( mu -hydrido)( mu -ethenyl)dirhenium octacarbonyl, ( mu -H)( mu CH equals CH//2)Re//2(CO)//8(I), in the presence of ethylene affords ( mu -hydrido)( mu -butenyl)dirhenium octacarbonyl complexes. A mechanism is proposed in which the initial step is photodissociation of CO from I, as photolysis of I in the presence of **1**3CO or PPh//3 results in CO substitution. Subsequent steps in the formation of the mu -hydrido mu -butenyl species are coordination of ethylene, insertion of ethylene into the Re-H or Re-ethenyl sigma bond, recoordination of CO, C-C or C-H reductive elimination to yield Re//2(CO)//8(1-butene), and oxidative addition of a vinylic C-H bond of coordinated butene.