Metallosalen-Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO₂ into Valuable Chemicals

A series of new metallosalen-based ionic porous organic polymers (POPs) were synthesized for the first time using a simple unique strategy based on the free-radical copolymerization reaction. Various techniques were used to characterize the physicochemical properties of these catalysts. These well-designed materials endowed high surface area, hierarchical porous structures, and enhanced CO₂ /N₂ adsorptive selectivity. Moreover, these POPs having both metal centers (Lewis acid) and ionic units (nucleophile) could serve as bifunctional catalysts in the catalytic conversion of CO₂ into high value-added chemicals without any additional co-catalyst under mild and solvent-free conditions, for example, CO₂ /epoxides cycloaddition and Nformylation of amines from CO₂ and hydrosilanes. The results demonstrated that the irregular porous structure was very favorable for the diffusion of substrates and products, and the microporous structural property resulted in the enrichment of CO₂ near the catalytic centers in the CO₂ -involved transformations. Additionally, the superhydrophobic property could not only enhance the chemoselectivity of products but also promote the stability and recyclability of catalysts.