Sustainable synthesis of multifunctional porous metalloporphyrin polymers for efficient carbon dioxide transformation under mild

Multifunctionalization of porous organic polymers (POPs) for working in concert on a substrate is now a research topic in CO2 catalysis, yet it remains challenging. This work describes a preand post-synthetic strategy to design metalloporphyrin-based azo-hierarchical porous ionic polymers (ZnTPP/QA-azo-PiPs), which were synthesized based on diazo-coupling reaction of tetra(4-aminophenyl) porphyrin zinc with tri/diphenols in aqueous solution under mild conditions, followed by etherification with quaternary ammonium bromide. This synthetic approach endows ZnTPP/QA-azo-PiP(1) with features of an improved surface area (181 m(2)/g), hierarchical porosity, and high-density active sites. ZnTPP/QA-azo-PiP(1) presented a noteworthy CO2 uptake of 1.77 mmol/g at 273 K and 1.0 bar and good CO2/N-2 selectivity of 44.8. As expected, ZnTPP/QA-azo-PiP(1) showed quantitative conversion and selectivity for a range of epoxides under mild conditions (1.0 MPa, 80 degrees C, 12 h) in the CO2 cycloaddition reaction. ZnTPP/QA-azo-PiP1 could been recycled easily and retained complete retention of activity and selectivity for over 7 cycles. Moreover, with efficacious activity in conversion of diluted CO2 (15% CO2 in 85% N-2, v/v), ZnTPP/QAazo-PiP(1) could smoothly catalyze CO2-involved reaction to produce oxazolidinones and N-formylated amines under mild conditions. This work promotes sustainable synthesis of advanced multifunctional POPs and gives great promise for their application in synthetic transformations of CO2. (C) 2020 Published by Elsevier Ltd.