SO3H-functionalized metal organic frameworks: an efficient heterogeneous catalyst for the synthesis of quinoxaline and derivatives†
An efficient alkylsulfonate functionalized metal organic framework (MOF), MIL-101-Cr–NH–RSO3H, has been successfully synthesized through a post-synthetic modification strategy of MIL-101-Cr–NH2 with 1,3-propanesultone reagent. The high surface area of the MIL-101-Cr–NH2 MOF guaranteed the high dispersion of –SO3H active species and the large pore size improved the contacting ability between the substrate and these active sites. The solid MIL-101-Cr–NH–RSO3H catalyst exhibited high catalytic performance in the preparation of quinoxaline derivatives by the condensation of benzene-1,2-diamines with 1,2-dicarbonyl compounds. Furthermore, the MIL-101-Cr–NH–RSO3H catalyst exhibits good stability, general applicability and excellent recycling performance.