CO₂ cycloaddition catalyzed by urea-based hydrogen bond donors in concert with polyether ionic liquids

To address the challenges of efficient CO 2 conversion and resource utilization, this research developed a synergistic catalytic system combining urea-based hydrogen bond donors (HBDs) with polyether ionic liquids to facilitate carbon dioxide cycloaddition with epoxides. The catalytic system utilizes the hydrogen-bonding capability of urea-based HBDs to polarize epoxide C-O bonds, while polyether ionic liquids facilitate CO 2 activation through electrostatic interactions and nucleophilic ring-opening. Experimental results demonstrated that HBD 2 with enhanced hydrogen-bonding strength and IL 2, achieved a 67.2 % yield with an associated catalytic turnover frequency (TOF) of 134 h −1 under mild conditions, outperforming individual components. Furthermore, the recyclability of the catalytic system was evaluated, revealing a decline in activity after the second cycle due to component loss. This work highlights the critical role of synergistic multi-site interactions in catalytic efficiency and provides insights into the design of multi-component systems for CO 2 cycloaddition.