Basic-Functionalized Ionic Porous Organic Polymers: Triple Roles in One for Highly Efficient and Recyclable...

The transformation of carbon dioxide (CO₂) into high-value chemicals is a significant step towards achieving the goal of "carbon neutrality". α-methylene cyclic carbonate, as an intermediate for the synthesis of many important organic compounds, is widely employed in industrial productions. In this work, a series of ionic porous organic polymers (IPOPs) with different basic-functionalized anions were successfully synthesized and adjusted to have certain BET surface areas and high contents of ion sites by post-modification. These basic-functionalized IPOPs could exhibit excellent catalytic performance for carboxylative cyclization of CO₂ at 30 °C and 1 bar in presence of silver salts, eliminating the use of the extra organic bases. In the whole catalytic reaction, the basic-functionalized anions could play triple roles: enriching CO₂ for further transformation, activating the hydroxyl groups of substrates to improve the catalytic performance, while coordinating with Ag atom to stabilize and regenerate catalyst. Notably, the catalytic system of DCX-4-Tet/Ag₂O exhibited excellent recyclability, and the yield of α-alkylidene cyclic carbonate was well maintained at 99 % after 5 cycles. To the best of our knowledge, the catalytic system was the first example of basic-functionalized IPOPs that played multiple roles for highly efficient CO₂ cyclization under mild conditions without any extra organic bases.