Redox reactions of metal carbonyls.: II. Kinetic studies on the disproportionation of Co 2(CO) 8 induced by N-bases

Abstract

The kinetics of the disproportionation reaction of Co 2(CO) 8 with triethylamine, benzylamine, cyclohexylamine and diethylamine were investigated employing stopped-flow technique. The kinetic behaviour is suggestive of two competing mechanisms, an amine-independent path involving probably a ratedetermining CO dissociation, followed by amine uptake, and an associative mechanism characterized by two or three consecutive attacks of the amine on the substrate, followed by a first-order decomposition of the final intermediate. The reaction rates are sensitive more to the steric characteristics of the entering ligand than to its basicity. Attention is drawn to correlate the reaction mechanism and the different structures of Co 2(CO) 8 in solution.