Bidirectional polymerization-constructed multifunctional organic polymer catalyst for CO-catalyst-free CO2 cycloaddition under mild conditions

The utilization of CO 2 as a sustainable carbon feedstock is an attractive strategy toward carbon neutrality, while the development of efficient heterogeneous catalysts under mild and co-catalyst-free conditions remains challenging. Herein, three porous organic polymer catalysts (PLZ, PLY, and PL-YZ) were synthesized through a one-step bidirectional polymerization strategy to systematically investigate the individual and synergistic roles of hydrogen-bond donor site (HBDs), Lewis basic N sites, and nucleophilic Cl − sites in CO 2 cycloaddition. Among them, PL-YZ exhibited the highest catalytic activity, affording chloropropylene carbonate in 93.1% yield with nearly 100% selectivity under optimized mild conditions (80 °C, 0.5 MPa CO 2 , 8 h) without any co-catalyst. In addition, PL-YZ maintained over 86% yield after five consecutive cycles and displayed broad substrate applicability toward various terminal epoxides. Kinetic analysis, in situ FT-IR spectroscopy, and DFT calculations consistently revealed that the cooperative interactions among HBD sites, Lewis basic N sites, and nucleophilic Cl − sites promote epoxide activation and ring-opening, facilitate CO 2 insertion, and accelerate cyclic carbonate formation. This study demonstrates the high product yields, selectivity, and recyclability of multifunctional porous polymer catalysts under mild conditions and establishes a practical design principle for integrating complementary active sites toward sustainable CO 2 conversion.