Bimetallic Nickel Complexes Containing Benzotriazole-Derived Diamine-Bisphenolate Ligands as Highly Active Catalysts for the Copolymerization of Carbon Dioxide with Cyclohexene Oxide: Synthesis, Catalysis, and Kinetics
Wei-Fang Tsao, Guanlin Liu, Yu‐Chia Su, Chu‐Chieh Lin, Bao‐Tsan Ko
Abstract
We reported the syntheses of a family of structurally well defined dicarboxylate and dinitrate dinickel complexes coordinated on ethyl N-substituted benzotriazole-containing diamine-bisphenolate derivatives. Dinickel carboxylate complexes 1–8 were highly active catalysts for CO2 copolymerization with cyclohexene oxide. Specifically, the trifluoroacetate-supported Ni complex 1 enabled the mediation of such a CO2 copolymerization with a high turnover frequency of up to 2521 h–1 under the optimized conditions, affording the related CO2-based polycarbonates having “controllable” and “immortal” characters. The kinetics of CO2/cyclohexene oxide copolymerization by 1 was systematically investigated, and this kind of copolymerization catalysis showed a first-order dependence on both the nickel catalyst and monomer concentrations.