LIGAND SUBSTITUTION PROCESSES IN TETRANUCLEAR METAL-CARBONYL CLUSTERS .1. CO4(CO)9(MU-2-CO)3 DERIVATIVES

Kinetic and mechanistic studies of carbon monoxide substitution processes in the tetranuclear metal carbonyl clusters, Co4(CO)12-n[P(OMe)3]n (n = 1, 2), are reported. Co4(CO)10[P(OMe)3]2 was found to proceed to Co4(CO)9[P(OMe)3]3 by a two-term rate law (dissociative and ligand-dependent paths) with the CO dissociative process being dominant at low incoming ligand concentrations. On the other hand, the rate of reaction of Co4(CO)11[P(OMe)3] with P(OMe)3 to afford Co4(CO)10[P(OMe)3]2 was strongly dependent on the concentration of trimethyl phosphite; making it difficult to assess the importance of the CO dissociative process. © 1979.