Efficient Cycloaddition of CO2 and Aziridines Activated by a Quadruple-Interpenetrated Indium-Organic Framework as a Recyclable Catalyst.

Abstract

On the basis of the global warming effect, it is of great significance to convert CO2 into the high value-added products oxazolidinones, but investigations on main-group-based metal-organic frameworks (MOFs) as heterogeneous catalysts still have not been reported so far. In this work, a quadruple-interpenetrated porous indium-based MOF, {[NH2(CH3)2][In(CPT)2]·3CH3CN·3DMA}n (1), is constructed from the organic ligand 3,5-bis(4'-carboxyphenyl)-1,2,4-triazole through solvothermal reactions, and N2 adsorption proves that the framework has a high Brunauer-Emmett-Teller surface areas with 2024 m2/g. The catalytic research on CO2 conversion reveals that compound 1 has high reactivity for the cycloaddition of CO2 with aziridines, and the product 3-ethyl-5-phenyloxazolidin-2-one can be obtained with a yield of 99% under mild conditions. In addition, 1 exhibits excellent activity for different kinds of substrates and can be reused at least five cycles without any significant deactivation, suggesting that 1 is a potential candidate for the chemical conversion of CO2 and aziridines. Mechanistic explorations indicate that the high efficiency of 1 is attributed to the indium center in the framework as a Lewis acid site, and the large porosity can enrich substrates. Importantly, 1 behaved as the first main-group MOF-based catalyst in the reported coupling reaction of CO2 with aziridines.