A Radical-Chain Mechanism for Dinuclear C-H Bond Formation

Article abstract of DOI:10.1021/ja00265a018

Both the formation of (Ph3PAu)2Os(CO)4 from Ph3PAuCH3 and H2Os(CO)4 and the formation of (Ph3PAu)Mn(CO)5 from Ph3PAuCH3 and HMn(CO)5 occur by radical-chain mechanisms.The chain carriers are .Mn(CO)5 and .Os(H)(CO)4, respectively, arising from hydrogen atom abstraction from the initial hydrides.Photolysis of a small amount of the appropriate dimer (Mn2(CO)10 or H2Os2(CO)8) generates the chain carrier and thus initiates the reaction.No such reaction occurs between Ph3PAuCH3 and HRe(CO)5, even in the presence of substantial amounts of .Re(CO)5.The formation of H2Os(CO)3PPh3 from Ph3P and H2Os(CO)4 also occurs by a radical-chain mechanism with .Os(H)(CO)4 as the chain carrier, and the reactions of Ph3PAuCH3 and Ph3P with H2Os(CO)4 can be simultaneously initiated.