Novel dinuclear calcium complexes have been employed as bifunctional catalysts for the ring-opening copolymerisation reaction of epoxides and cyclic anhydrides. The catalysts exhibited good performance and quantitative formation of ester linkages for the poly(CHO-alt-PA) production under mild reaction conditions and in the absence of a cocatalyst. Furthermore, these catalysts demonstrated tolerance to a variety of bio-sourced epoxides/phthalic anhydrides, providing access to a range of potentially functionalisable polyesters. On the other, polymerisation kinetic analyses revealed a half-order dependence on catalyst concentration and first-order dependence on cyclic anhydride concentration, whilst MALDI-ToF analyses supported an initiation step involving the ring-opening of the epoxide. Taken together, these findings underpin a mononuclear pathway, with the ring-opening of the cyclic anhydride identified as the rate-limiting step in the process.

中文翻译：

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钙催化环氧化物和环酸酐的开环共聚


新型双核钙配合物已被用作环氧化物和环状酸酐的开环共聚反应的双功能催化剂。该催化剂在温和的反应条件和不存在助催化剂的情况下表现出良好的性能和定量形成聚(CHO-alt-PA)的酯键。此外，这些催化剂表现出对各种生物来源的环氧化物/邻苯二甲酸酐的耐受性，从而提供了一系列潜在的可官能化聚酯。另一方面，聚合动力学分析揭示了对催化剂浓度的半阶依赖性和对环酸酐浓度的一阶依赖性，而 MALDI-ToF 分析支持涉及环氧化物开环的引发步骤。总而言之，这些发现支持了单核途径，其中环酸酐的开环被确定为该过程中的限速步骤。