Bimetallic nickel and cobalt complexes as high-performance catalysts for copolymerization of carbon dioxide with cyclohexene oxide†
Abstract
New bimetallic nickel, cobalt and zinc complexes bearing a bis(benzotriazole iminophenolate) ligand and ancillary acetate groups were developed for CO2/epoxide copolymerization. Ni and Co complexes are active catalysts for the copolymerization of cyclohexene oxide (CHO) and CO2 without co-catalysts. Particularly, well-defined di-Ni 1 was found to effectively copolymerize CHO with CO2, giving copolymers with a high molecular weight and a high carbonate linkage content. This is the first example of a dinuclear nickel acetate complex that is efficient for CO2/CHO copolymerization as well as for the formation of highly alternative poly(cyclohexene carbonate) in a controllable manner.