High yield cycloaddition of carbon dioxide to epoxides catalyzed by metal–organic frameworks

A series of metal–organic frameworks (MOFs) based on trimesic acid (also knows benzene tricarboxylic acid [btc]) have been synthesized by a solvothermal procedure which exhibit excellent catalytic fixation of CO2. Cycloaddition of CO2 to epoxides to produce cyclic carbonates is quite promising. The chemical fixation of CO2 reported here is solvent free and carried out under moderately mild conditions. All the MOFs [Zn-btc (1), Co-btc (2), Ni-btc (3), and Cu-btc (4)] were synthesized under same experimental conditions yet possess different structural and catalytic properties. All the catalysts follow first-order kinetics, and Zn-btc (1) proved to be the most catalytically active catalyst among all, with ∼100% yield with a total turnover number of 18,845 mol−1 and an initial turnover frequency (hour−1) of 946 with respect to the cyclic carbonate. All MOFs (1–4) show almost 100% conversion in these reactions. The same reaction using other metal (Co, Ni, Cu)-btc compounds has also resulted in products with more than 94% yield, creating an extra impact on the importance of the work.