It is particularly important to be able to synthesize well-defined block copolymers from one-pot monomer mixtures in a metal-free manner. Herein, switchable copolymerization between the ring-opening alternating copolymerization (ROAC) of anhydrides with epoxides and the ring-opening polymerization (ROP) of lactones using imidazolium ionic liquids has been investigated in detail. It is found that a simple ionic liquid, 1-ethyl-3-methylimidazole chlorine (EMIMCl), was efficient to bridge ROAC and ROP, producing well-defined block polyesters from anhydrides, epoxides and lactones in a one-step strategy. The DFT calculation and experimental results indicated that the sequential transformation of mixed monomers mainly depends on the synergistic effect of anions and cations of ionic liquids, where the generating alkoxide anions are the key to regulate ROAC and ROP, and imidazolium cations (EMIM⁺) contribute to the monomer activation and inhibition of potential side reactions. EMIMCl exhibits high catalytic activity and selectivity in a multi-component system, which enables the switchable copolymerization of mixed monomers from ROAC to ROP. This study provides a new route for the facile synthesis of block polyesters using a metal-free catalytic system.

中文翻译：

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咪唑鎓离子液体催化混合单体的可切换共聚

尤其重要的是能够以无金属的方式从一锅单体混合物合成明确的嵌段共聚物。在此，详细研究了酸酐与环氧化物的开环交替共聚（ROAC）和使用咪唑鎓离子液体的内酯开环聚合（ROP）之间的可切换共聚。研究发现，一种简单的离子液体，1-乙基-3-甲基咪唑氯（EMIMCl），可以有效地桥接ROAC和ROP，通过一步策略从酸酐、环氧化物和内酯生产明确的嵌段聚酯。DFT计算和实验结果表明，混合单体的顺序转化主要依赖于离子液体阴离子和阳离子的协同作用，其中生成的醇盐阴离子是调节ROAC和ROP的关键，咪唑阳离子（EMIM+ ^）贡献单体的活化和潜在副反应的抑制。EMIMCl在多组分体系中表现出高催化活性和选择性，使得混合单体从ROAC到ROP可切换共聚。这项研究为使用无金属催化体系轻松合成嵌段聚酯提供了一条新途径。