If cycloaddition of CO₂ to epoxides is to become a viable non-redox CO₂ fixation path, it is crucial that researchers develop an active, stable, selective, metal-free, reusable, and cost-effective catalyst. To this end, we report here a new catalyst that is based on imidazolinium functionality and is synthesized from an unprecedented, one-pot reaction of the widely available monomers terephthalaldehyde and ammonium chloride. We show that this covalent organic polymer (COP)-222 exhibits quantitative conversion and selectivity for a range of substrates under ambient conditions and without the need for co-catalysts, metals, solvent, or pressure. COP-222 is recyclable and has been demonstrated to retain complete retention of activity for over 15 cycles. Moreover, it is scalable to at least a kilogram scale. We determined the reaction mechanism by using quantum mechanics (density functional theory), showing that it involves nucleophilic-attack-driven epoxide ring opening (ND-ERO). This contrasts with the commonly assumed mechanism involving the concerted addition of chemisorbed CO₂.

如果要使环氧化物中的CO ₂环加成成为可行的非氧化还原CO ₂固定途径，至关重要的是，研究人员必须开发出一种活性，稳定，选择性，无金属，可重复使用且具有成本效益的催化剂。为此，我们在此报告一种基于咪唑啉鎓官能团的新型催化剂，该催化剂是通过广泛使用的单体对苯二甲醛和氯化铵的空前，一锅法反应合成的。我们表明，这种共价有机聚合物（COP）-222在环境条件下对一定范围的底物表现出定量的转化率和选择性，而无需助催化剂，金属，溶剂或压力。COP-222是可回收的，并且已被证明可以在15个以上的循环中完全保留其活性。而且，它可以扩展到至少一公斤规模。我们通过量子力学（密度泛函理论）确定了反应机理，表明它涉及亲核攻击驱动的环氧化物开环（ND-ERO）。这与通常一致的机制有关，即协同添加化学吸附的一氧化碳。₂。