Bisimidazole-functionalized manganese porphyrin promoted cycloaddition of epoxides and CO2 under atmospheric pressure
Faliang Gou, Qianni Bian, Honghong Pan, Jianan Li, Huangfei Tang, Xu Jiang
Abstract
Three bisimidazole-modified manganese porphyrin complexes have been synthesized and applied as bifunctional catalysts for the chemical conversion of epoxides and atmospheric CO 2 into cyclic carbonates without any co-catalysts and solvents. Imidazole-modified alkoxyl chains at different porphyrin positions modulate the distance between the imidazole group and the manganese center of the porphyrin, thus considerably affecting their catalytic properties. Catalyst E- m 6 shows the best catalytic performance under optimal conditions. Foundational kinetic study results catalyzed by E- o 6, E- m 6 and E- p 6 show the apparent activation energies E a ( E- m 6 ) value is the lowest, only 41.7 kJ/mol, revealing its relative position of imidazole group and porphyrin manganese center is the most appropriate.