Novel porous organic polymers functionalized by metalloporphyrin and phosphonium salts for the efficient synergistic catalysis of CO2 conversion under mild conditions

Functional porous organic polymers (POPs) have been extensively developed as heterogeneous catalysts for carbon dioxide conversion. However, exploring a general strategy to incorporate versatile active moieties into POPs is still a big challenge. In this study, a post-synthesis modification strategy was suggested for the fabrication of metalloporphyrin- and phosphonium-functionalized POPs. The as-prepared POP catalysts PPh(2)PStR-PMtVPP (R = C2-C12) were characterized by FT-IR, SEM, TEM, XPS, TGA, ICP, and TPD measurements. The results demonstrated that the PPh(2)PStR-PMtVPP catalysts were mesoporous and possessed a high adsorption capacity for CO2, which was advantageous for the cycloaddition reaction of CO2 and epoxides. Thanks to their rich Lewis acid sites and nucleophilic groups, PPh(2)PStR-PMtVPP could cooperatively activate substrates and achieve efficient synergistic catalysis for CO2 cycloaddition with epoxides. The effects of the phosphonium structure and different metal centers, as well as reaction conditions, on the catalytic performances of the functional POPs are discussed in detail. Under the optimized conditions, PPh(2)PStD-PCoVPP-1 could efficiently and selectively catalyze the coupling of CO2 and epoxides at 80 degrees C and 0.1 MPa CO2. Moreover, PPh(2)PStD-PCoVPP-1 could be easily separated and recycled five times without any obvious loss of catalytic activity. This study thus offers a powerful strategy for the fabrication of efficient bifunctional catalysts for CO2 conversion.

Automated summary

This study presents a post-synthesis modification strategy to incorporate versatile active moieties into functional porous organic polymers (POPs) for efficient CO2 conversion. The as-prepared POP catalysts exhibit mesoporous structure and high adsorption capacity for CO2. The catalysts can cooperatively activate substrates and efficiently catalyze the cycloaddition reaction between CO2 and epoxides.