Dynamic Foldamer Catalyst Enables Efficient Copolymerization of CO2 and Epoxides

Foldamer catalysis has been developed prosperously in various fields due to its enzyme-mimic feature with admirable activity and selectivity, while there is still a blank for its application in polymer synthesis. Herein, we report a dynamic foldamer catalyst for the boosted copolymerization of CO2/propylene oxide (PO) based on the hydrogen bonding-enhanced helicity of the conventional polymeric catalyst. Through attaching a bulky aluminum aminoporphyrin active site into poly(methacryloyl chloride), a foldamer catalyst was facilely fabricated, where the hydrogen bonding between amides obviously enhanced the helicity derived from the aggregation of porphyrin units along the polymer backbone. The optimized foldamer catalyst FCAT3 displayed much higher catalytic activity (7300 h(-1)) than the conventional polymeric catalyst (1400 h(-1)) at the same conditions. Notably, the dynamic foldamer catalyst showed an enzyme-like temperature-dependent attribute derived from the hydrogen bonding-induced folding--unfolding process, allowing high catalytic activity for homogeneous CO2/PO copolymerization (loose folding) at polymerization temperature and easy heterogeneous catalyst separation (tight folding) at ambient temperature. The obtained colorless poly(carbonate-ether) also displayed better pressure-sensitive adhesive performance than commercial counterparts. The present strategy provides a platform for the design of dynamic foldamer catalysts not only for CO2/epoxides or anhydride/epoxides copolymerization but also for lactone ring-opening polymerizations.