Porous Metallosalen Hypercrosslinked Ionic Polymers for Cooperative CO₂ Cycloaddition Conversion

Abstract

Metallosalen-based porous ionic polymers have the potential to combine the merits of homogeneous organometallics and heterogeneous porous ionic catalysts in carbon dioxide (CO2) cycloaddition conversion. Herein, a series of porous metallosalen hypercrosslinked ionic polymers (M-HIPs) were synthesized through a simple method. The M-HIPs with high metal and Br anion concentrations were evaluated by catalyzing CO2 cycloaddition with epoxides. Because of the cooperative effect between Br anions and metal active species in the porous channel, M-HIPs exhibited a high CO2 catalytic performance even under ambient conditions. Among the M-HIPs (M = Co, Al, Zn), Co-HIP showed the best catalytic performance for various epoxides and was stable after five runs. Density functional theory calculations support the fact that Co-HIP had the lowest energy barrier, which agreed with the experimental results.