Bis(β-ketoamino) copper complexes for vinyl polymerization of norbornene: Correlation between precursor structure and catalytic activity

Abstract

A novel fluorinated bis(β-ketoamino) copper complex was synthesized and characterized. Norbornene polymerizations with bis(β-ketoamino) copper complexes activated with methylaluminoxane (MAO) were investigated. The highest catalytic activity up to now reported for copper based systems in norbornene polymerization was achieved using fluorinated bis(β-ketoamino) copper/MAO. The influence of precursor structure including steric and electronic effects on catalytic activity for norbornene polymerization was evaluated in detail. Bulky steric substituents and strong electron-withdrawing groups can enhance catalytic activity of precursor for norbornene polymerization through a dissociative mechanism. The influences of polymerization parameters such as polymerization temperature and Al/Cu ratio on norbornene polymerization with bis(β-ketoamino) copper catalysts were also examined. Norbornene polymerization catalyzed by bis(β-ketoamino) copper complexes/MAO proceeded on Cu(I) species through a coordination/insertion mechanism to produce vinyl-addition polynorbornene.