Potassium‐ion‐bound porous organic polymers having crown ether struts enable cooperative conversion of CO2 to cyclic carbonates under mild conditions

Abstract Porous organic polymers (POPs) are a new emerging class of heterogeneous catalysts for the CO 2 cycloaddition with epoxides in recent decades. However, the controllable construction of multifunctional POPs that are capable of activating substrates still remains a huge challenge due to the difficulty in the precise design of tailored building blocks and the optimization of reaction conditions. In the present work, we designed and developed a simple and efficient synthesis of a series of crown‐ether‐functionalized POPs (CE‐POPs) through the Schiff‐base condensation reaction using trans ‐di(aminodibenzo)‐18‐crown‐6 as functional knots and various trialdehyde‐type monomers as connectors in refluxed DMF. Considering the excellent molecular recognition phenomenon of potassium ions to 18‐crown‐6, these well‐prepared potassium‐ion‐bound POPs (KI@CE‐POPs) possessed huge potential to synergistically catalyze the cycloaddition reaction of CO 2 with epoxides to afford cyclic carbonates under solvent‐free and mild conditions. More interestingly, the task‐specific introduction of phenolic hydroxyl groups or triazine units into the polymeric backbones achieves a significant improvement of catalytic performance. In addition, the substrate scope of the reaction and the recyclability and reusability of the catalyst were also examined. Therefore, this new catalyst may provide new inspiration for the activation and utilization of CO 2 .