The influence of various anions on the physicochemical properties of the Dicationic imidazolium-based ionic liquids

Dication-based ionic liquids (DILs) are a new generation of amphiphilic molecules.1 DILsconsist of a doubly charged cation that is composed of two singly charged cations linked byan alkyl chain. A singly charged anion is associated with each of the charged parts of thecation in the gas phase.2 Recently, the new structures have emerged as a new option forapplications, for instance, uses as solvents, surfactant, lubricant, and for nanoparticle coating3 as well as catalysts in the preparation of biodiesel through cottonseed oil transesterification4due to their high thermal stability, broad liquid range, and biological activities.5 To choose ordesign the suitable DILs for a variety of applications, it is necessary to understand theirstructures and interactions in various DIL systems. It is, however, time-consuming and costintensiveto study the physicochemical properties of all DILs by experiments. Thus, study ofthe physicochemical properties of DILs by theoretical computation is an efficient andnecessary approach.