A Porphyrin-Based Porous rtl Metal-Organic Framework as an Efficient Catalyst for the Cycloaddition of CO2 to Epoxides

摘要

A porous rtl metal-organic framework (MOF) [Mn5L(H2O)(6)center dot(DMA)(2)]center dot 5DMA center dot 4C(2)H(5)OH (1 center dot Mn) (H10L=5,10,15,20-tetra(4-(3,5-dicarboxylphenoxy)phenyl)porphyrin; DMA=N,N'-dimethylacetamide) was synthesized by employing a new porphyrin-based octacarboxylic acid ligand. 1 center dot Mn exhibits high Mn-II density in the porous framework, providing it great Lewis-acid heterogeneous catalytic capability for the cycloaddition of CO2 with epoxides. Strikingly, 1 center dot Mn features excellent catalytic activity to the cycloaddition of CO2 to epoxides, with a remarkable initial turnover frequency 400 per mole of catalyst per hour at 20 atm. As-synthesized 1 center dot Mn also exhibits size selectivity to different epoxide substrates on account of their steric hindrance. The high catalytic activity, size selectivity, and stability toward the epoxides on catalytic cycloaddition of CO2 make 1 center dot Mn a promising heterogeneous catalyst for fixation and utilization of CO2.