Multifunctional Linear and Hyperbranched Five-Membered Cyclic Carbonate-Based Polymers Directly Generated from CO₂ and Alkyne-Based Three-Component Polymerization

Fixing carbon dioxide (CO2) into polymeric materials is a subject of enduring interest but limited to very few efficient polymerizations. In this work, a facile Pd(OAc)2/LiOtBu-catalyzed one-pot, three-component polymerization of CO2, bis(propargylic alcohol)s, and aryl dihalides under atmospheric pressure is developed. Linear and hyperbranched multifunctional five-membered cyclic carbonate (5CC)-based polymers with well-defined structures, high weight-average molecular weights (Mw up to 42500), and versatile properties such as aggregation-induced emission as well as chiral and porous properties are successfully produced in excellent yields (up to 96%). The reaction mechanism was well investigated via the density functional theory calculation and in situ Fourier transform infrared spectroscopy, both indicating that there is synergistic reaction effect among CO2, bis(propargylic alcohol)s, and aryl dihalides. The polymers could be postfunctionalized by amines via catalyst-free regioselective ring-opening reaction with 100% grafting ratio. Thus, this work not only develops a new way to directly fix CO2 into polymeric materials but also provides the 5CC-based polymers with versatile properties, showing great potentials in diverse areas.