A copper(ii) metal–organic framework with 2,2-dimethylglutarate and imidazole ligands: synthesis, characterization and catalytic performance for cycloaddition of CO2 to epoxides

Abstract

A new three-dimensional (3D) framework with the general formula {[Cu(μ₃-dmg)(im)₂]·3H₂O}_n (1) was synthesized using an aliphatic dicarboxylic acid linker 2,2-dimethylglutarate (dmg²⁻) and nitrogen-containing imidazole ligand (im) under conventional methods. 1 was characterized by FT-IR spectroscopy, elemental analysis, single crystal and powder X-ray diffractions, and thermal analysis techniques. Additionally, the optical and topological properties of compound 1 were also investigated. The single crystal X-ray data exhibit that 1 is an interesting 3D framework and it has a I4₁/a space group, which originates from two imidazole ligands, one dmg and three lattice water molecules. Topologically, 1 displays a lvt-a topology with the point symbol of {4.8.10}. In addition, the catalytic activity of compound 1 was investigated in the CO₂ conversion into cyclic carbonates. It was found that compound 1 was an active catalyst even at low catalyst loading under 0.1 MPa CO₂ at 80 °C. The yields of 23–99% were obtained. Compound 1 can be recycled at least four times without significant compromise in the activity in the first three catalytic reactions.