Highly Active and Readily Accessible Proline-Based Dizinc Catalyst for CO /Epoxide Copolymerization.

In the pursuit of CO -based materials, the development of efficient catalysts for the alternating copolymerization of CO and epoxides to give polycarbonates is receiving particular attention. Desirable attributes for such catalysts are high copolymerization activity at low CO pressure, as well as chemo- and stereocontrol over the formed polymer. Here, we report a novel chiral zinc catalyst that can be isolated in 97 % yield from commercial sources, and that produces polycarbonates selectively from neat cyclohexene oxide under 1 bar of CO pressure at temperatures above 50 °C. At 80 °C reaction temperature, TONs of 1684 and initial TOFs up to 149 h were measured, producing an isotactic-enriched polycarbonate with a probability P of 65 % for the formation of a meso diad. Insight into the dinuclear nature of the active species and the copolymerization progress has been gained from structural and spectroscopic studies.