Insight into the mechanism of decarbonylation of methanol by ruthenium complexes; a deuterium labelling study

Abstract

In the reaction of [RuHClP₃] (P = PPh₃) with NaOMe in methanol, the product is [RuH₂(CO)P₃]. Short reaction times show that the final product is formed through [RuH₄P₃] as the major intermediate. Using NaOCD₃ in CD₃OD, the first formed product is [RuH₄P′₃] (P′ is PPh₃ partially deuterated in the ortho positions of the aromatic rings). Further reaction leads to a mixture of [RuH_nD_2−n(CO)P₃] (n = 0, 22%; n = 1, 2 isomers each 28%; n = 2, 22%). Mechanistic aspects of both steps of the reaction are explored and, together with previously published calculations, they provide definitive mechanisms for both dehydrogenation and decarbonylation in these interesting systems.