Poly(norbornene) block copolymer-based shell cross-linked micelles with Co(iii)–salen cores

Abstract

A series of poly(norbornene) based amphiphilic triblock copolymers containing covalently attached salen ligands in the hydrophobic block, a cinnamate group-containing middle block and a poly(ethylene glycol) methyl ether-containing repeat unit as the hydrophilic block have been synthesized using living ring-opening metathesis polymerization. Micellar assemblies constructed of these copolymers were stabilized by cross-linking of the cinnamate-containing middle block using UV irradiation. The resulting shell cross-linked micelles (SCMs) have salen ligands selectively located within the hydrophobic core that are modified further by metal complexation with cobalt ions to produce SCMs core supported Co(III)-salen catalysts. The catalytic activities of these SCM catalysts were systematically investigated by hydrolytic kinetic resolution of epichlorohydrin. It was found that the composition of the copolymers and the size of SCM have substantial influences on the catalytic activity of SCMs catalysts.