The cycloaddition reaction of CO₂ and various epoxides is one of the most promising approaches for CO₂ fixation. Inspired by the synergistic catalytic mechanism based on the double activation model of an epoxide, it's well documented that most metal-based catalysts often show higher catalytic activities than traditional organocatalysts under identical conditions. As a result, the feasible construction of a series of metal-functionalized porous organic polymers (denoted as metal-POPs) can provide the opportunity for integrating the advantages of homogeneous catalysis for high activity and heterogeneous catalysis for facile recyclability. Indeed, metal-POPs are identified as excellent heterogeneous catalysts for capturing and simultaneously converting CO₂ into cyclic carbonates, thereby affording quite high activities and selectivities. This review describes the recent advancements with regard to the design and synthesis of metal-POPs featuring accessible active sites and then discloses the structure–property relationship in metal-catalyzed CO₂ cycloaddition reactions with epoxides. From the perspective of the design of task-specific monomers and special connectors, we mainly focus on how to introduce metal species into polymer backbones. Also, we discuss multifunctionalization of metal-POPs through the introduction of functional groups including CO₂-philic heteroatoms and ionic moieties. Consequently, current challenges and future research efforts are further elaborated for the requirement of practical industrial applications.

中文翻译：

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在具有可接近金属位点的多孔有机聚合物上捕获二氧化碳并同时转化为环状碳酸酯方面的最新进展

CO ₂和各种环氧化物的环加成反应是用于CO ₂固定的最有前途的方法之一。受到基于环氧化物双活化模型的协同催化机制的启发，有充分的文献证明，大多数金属基催化剂在相同条件下通常表现出比传统有机催化剂更高的催化活性。结果，一系列金属官能化的多孔有机聚合物（表示为金属POPs）的可行构造可提供机会，以整合均相催化（用于高活性）和非均相催化（用于易于回收）的优点。实际上，金属POPs被认为是捕获和同时转化CO _2的优秀多相催化剂。生成环状碳酸酯，从而提供相当高的活性和选择性。这篇综述描述了具有可访问的活性位点的金属-POPs的设计和合成方面的最新进展，然后揭示了金属与环氧化物催化的CO ₂环加成反应中的结构-性质关系。从特定任务的单体和特殊连接器的设计角度来看，我们主要集中于如何将金属种类引入聚合物主链。此外，我们讨论了通过引入官能团（包括CO _2-亲和性杂原子和离子部分）对金属POPs进行多功能化的问题。因此，针对实际工业应用的需求，进一步阐述了当前的挑战和未来的研究工作。