New Ionic Liquids of <i>N</i>,<i>N</i>′-Dialkylbenzimidazolium Salt Comprising Copper(II) Ions

Three new metal-containing ionic liquids (ILs) of N,N′-dialkylbenzimidazolium of [(CnH2n+1)2-bim]2[CuCl4] (n = 8, 10, 12) (bim = benzimidazole) were synthesized, and the structures were characterized by X-ray crystallography, IR spectroscopy, and elemental analysis. The cations of three complexes adopted U-shaped conformations and were packed in a bilayer fashion. The thermal behaviors of three complexes were studied by differential scanning calorimetry (DSC) and thermogravimetry (TG). The ionic conductivities measurements showed that the ionic conductivities of the three complexes were different in absolute ethanol, and the ionic conductivities may relate to the coordination environment found for Cu(II) of three complexes.