A mononuclear Cu(II)-based metal-organic framework as an efficient heterogeneous catalyst for chemical transformation of CO2 and Knoevenagel condensation reaction

Abstract

A novel 2D Cu(II) metal-organic framework, [(Cu(L)2·(H2O)2·(NO3)2]n (namely 1), can be synthesized by the self-assemble of 4-(5-methyl-3-pyridine)-1,2,4-triazole (namely L) and Cu(II) ion. The as-synthesized MOF 1 has mononuclear {CuN4O2} and only one coordination mode of this L. The inorganic parts and organic ligands are connected by each other to construct a 2D layer framework. The obtained MOF 1 has been characterized and analysed in detail by single crystal X-ray diffraction, powder X-ray diffraction (PXRD), elemental analysis, Fourier-transform infrared spectra (FT-IR), and thermogravimetric analysis (TGA). Furthermore, MOF 1 has open Cu metal sites and lots of N atoms as Lewis basic sites, resulting in that it can be employed as a heterogeneous catalysis for chemical transformation of CO2 and epoxides into targeted cyclic carbonate and Knoevenagel condensation reaction. It also can be reused four times at least without significantly reduced activity for these catalytic reactions.