A hollow viologen-based porous organic polymer for the catalytic cycloaddition of CO2

Abstract

Converting CO₂ into high value-added products such as cyclic carbonates can aid alleviation of the greenhouse effect because CO₂ is a renewable C1 resource with high reserves. Benefiting from the two pyridinium rings as dicationic sites and free anions as nucleophilic substances, viologen-based porous organic polymers (VPOPs) have become important catalysts in the cycloaddition of CO₂. We changed the micromorphology of VPOPs to obtain viologen-based porous organic polymers with a hollow-sphere structure (HVPOPs). Among the (H)VPOPs, HVPOP-Br exhibited high efficiency, reusable stability and substrate universality in the cycloaddition reactions of CO₂ into cyclic carbonates. In a series of comparative experiments, the importance of microscopic morphology and anion of porous organic polymers in the cycloaddition reactions of CO₂ was demonstrated.