A dual-walled cage MOF as an efficient heterogeneous catalyst for the conversion of CO2 under mild and co-catalyst free conditions

A novel 3D -> 3D interpenetrated Zn-polyhedral MOF [Zn-6(TATAB)(4)(DABCO)(3)(H2O)(3)]center dot 12DMF center dot 9H(2)O (1) (H(3)TATAB = 4,4',4 ''-s-triazine-1,3,5-triyl-tri-p-aminobenzoic acid, DABCO = 1,4-diazabicyclo[2.2.2]-octane) based on a dual-walled icosahedral cage has been assembled by incorporating zinc paddlewheel units with nitrogen-rich tritopic carboxylate ligands. Owing to the high density of Lewis acid active sites and affinity to CO2 of the cage, this material exhibits an excellent catalytic efficiency in the cycloaddition of propylene oxide with CO2 into propylene carbonate under mild conditions (100 degrees C and ambient CO2 pressure) with a high yield of 99% over 16 h. Moreover, the catalytic reaction is environmentally friendly without any need for co-catalysts and solvents.