Structural Design of Mn-Metal-Organic Frameworks toward Highly Efficient Solvent-Free Cycloaddition of CO2

Three new manganese-based metal-organic frameworks (Mn- MOFs), [Mn(L) (H2O)]center dot 2DMA (1), [Mn-2(L)(2)(H2O)(3)]center dot 2DMA (2), and [Mn-2(L)(2)(DMF)(2)(H2O)]center dot 3DMF (3), have been synthesized with the ligand H2L (Nphenyl-N'-phenylbicyclo[2.2.2]oct-7- ene- 2,3,5,6-tetracarboxdiimide dicarboxylic acid). The secondary building units (SBUs) of the Mn-MOFs are controlled by changing the anions of the manganese salts, and the structures are modified from two-fold interpenetrating to non-interpenetrating by adjusting the mixed solvent systems. Along with the structural modification of the MnMOFs, we optimized their catalytic activities for the reaction of CO2 and epoxides toward cyclic carbonates. Both the activity and reusability of the Mn-MOFs are successfully improved in the solvent-free cycloaddition of CO2 with various epoxides under the mild conditions of atmospheric pressure and 70 degrees C.

Automated summary

Three new manganese-based metal-organic frameworks have been synthesized with modified structures for improved catalytic activity in the reaction of CO2 and epoxides towards cyclic carbonates. The structures of the Mn-MOFs are controlled by changing the anions of the manganese salts, and the catalytic activities are optimized under mild conditions.