Bimetal-organic frameworks (Cux-Cr100-x–MOF) as a stable and efficient catalyst for synthesis of 3, 4-dihydropyrimidin-2-one and 14-phenyl-14H-dibenzo [a, j] xanthene

Abstract

Successful three-dimensional bimetallic metal organic frameworks with different Cu/Cr ratios have been prepared under solvothermal conditions using chromium nitrate and copper nitrate as a bimetal and 1, 4 benzene dicarboxylic acid as an organic linker. Numerous techniques were used to characterize the resulting samples such as XRD, BET, SEM, TEM, SEM-EDS and FT-IR measurements. Combination of Cu and Cr in the same framework will cause some deformation in the structure and decrease in the surface area and pore size distribution. This decrease may be due to the incorporated copper have higher atomic weight than chromium ion. The acidic properties can be measured by non-aqueous titration. The catalytic performance of bimetallic MOFs was confirmed through the synthesis of 3, 4-dihydropyrimidin-2-one and 14-Phenyl-14H-dibenzo [a, j] xanthene. pure Cu-BDC and Cr-MIL-101 possesses a relatively lower surface acidity as well as lower catalytic activity. It surprising that, the combination between copper and chromium in the same framework can significantly enhance the acidity and catalytic activity of the as-synthesized catalysts which may be due to the synergetic effect. Keywords: Mixed MOFs, Xanthene, Dihydropyrimidinones, Cu-BDC, Cr-MIL-101