Experimental and theoretical investigation of spectroscopic and electronic properties of some ionic liquids

In this study, the spectroscopic and electronic properties of some ionic liquids (ILs) have been investigated experimentally and theoretically. The variations in the interionic interactions depending on the alternation in anion-cation pairs have been outlined. The variations in the spectroscopic and electronic properties of ionic liquids in the case of extension and shortening of chain length of the cation were investigated as well. The calculations have been performed by using some basis sets in Density Functional Theory with the B3LYP method in Gaussian 16. Geometric optimization and vibrational frequencies of the structures have been calculated and their vibrational modes were assigned. Experimental IR and Raman spectra results have been compared with the theoretically calculated results. The electronic and magnetic features of the ILs under study have been examined by using UV and NMR techniques along with the calculations from Time-Dependent Density Functional Theory and GIAO method. Furthermore, the electrostatic characteristics (electrostatic potential surface, atomic charges, etc.), interionic weak interactions (Hydrogen bonding, Van der Waals interactions, and steric effects, critical points from topology analysis), and reactivity properties (electronegativity, chemical hardness, chemical potential, etc.) of ILs have been obtained.