Carbon dioxide-based functional polycarbonates: Metal catalyzed copolymerization of CO2 and epoxides

Proof of principles studies by Inoue and coworkers in the late 1960s clearly illustrated the poorly controlled coupling of CO2 and epoxides to provide polycarbonates. These early studies utilizing inadequately defined zinc catalysts derived from diethyl zinc and water have led to the development of a variety of catalysts for these processes over the last two decades. Numerous catalyst systems have been shown to be very effective and selective at affording perfectly alternating copolymers, including those with high levels of regio- and stereo-selectivity. The vast majority of the current literature reports upon the synthesis of hydrophobic polycarbonates which lack functionalities. In this review we will summarize the reports which utilize these well-developed metal-catalyzed CO2/epoxides copolymerization processes to prepare high value-added functionalized polymeric materials for a variety of applications.