The role of phosphine in cobalt-catalyzed carbonylative polymerization of N-alkylaziridine

A series of CH3COCo(CO)3L complexes bearing various phosphine ligands were synthesized and studied as precatalyst for the title polymerization. The effect of the electron-donating ability of phosphine ligands on the polymerization rate and the formation of β-lactam byproduct are discussed. The production of the β-lactam byproduct is proposed to have been caused by catalyst decomposition.