Bottom-up oriented synthesis of metalloporphyrin-based porous ionic polymers for the cycloaddition of CO2 to epoxides

Porphyrin-bearing porous materials have attracted great interest in the field of CO 2 chemical fixation, yet one-pot fabricating networks with multifunctionality through bottom-up oriented synthetic method is still scarce and balancing the multifunction and the porosity remains challenging. Herein, we designed an ionic liquid-based building unit with rigidity and contortion and then synthesized a porous ionic polymers (PiPs) consisting of electrophilic metalloporphyrin and nucleophilic imidazolium ionic liquids (ILs) units by “Adler-Longo” methodology and metallization reaction. The as-prepared bifunctional polymer ZnPor-PiP possessed improved specific surface area, abundant micro/mesoporosity, noteworthy CO 2 uptake and acceptable CO 2 /N 2 selectivity. Legitimately, ZnPor-PiP exhibited good catalytic performance for the synthesis of cyclic carbonates from CO 2 and epoxides under mild conditions owning to the cooperative effect between the metal active center and the IL moieties, as well as the unique structural properties. Intriguingly, ZnPor-PiP gave a good substrate expansibility for this cycloaddition reaction and showed no obvious decrease in catalytic activity over six recycles. Furthermore, this bifunctional solid catalyst could efficiently convert diluted CO 2 (15% CO 2 in N 2 ) with propylene epoxide into propylene carbonate at 100 °C and 3.0 MPa. This bottom-up oriented strategy is of great importance for the development of functionalized porphyrin-based PiPs and the as-designed polymers highlights the potential for targeting CO 2 capture and transformations.