Spectroscopic and Molecular Dynamics Study of Solvation and Translational Dynamics in Ionic Liquids

Room temperature ionic liquids (RTILs or ILs) are a class of chemical salts that have low melting points and are liquids at room temperature. The cations are either nitrogen-based (ammonium, imidazolium, pyrazolium, pyridinium, and pyrrolidinium), sulfur-based (sulfonium), or phosphate-based (phosphonium), and the anions are either organic (e.g. acetate) or inorganic (e.g. PF₆ –). For each class of cations and anions, many modifications are possible, such as changing alkyl chain length or adding additional
functional groups. The number of ILs that can be synthesized is, therefore, nearly infinite.1 In addition to pure ILs, mixtures of ILs have also been used in many applications.2–11 By creating mixtures of ILs, the number of possible ILs increases exponentially and these mixtures of ILs have enabled additional methods for fine-tuning the physical and chemical properties of these materials. With such a large number of available ILs, a better
understanding of the structure and dynamic of ILs is needed to facilitate the development of task-specific ILs.