LAUSR

Abstract Five imidazolium-based ionic liquids with the Bis(trifluoromethylsulfonyl)imide ([Tf2N]−), Eethylsulfate ([EtSO4]−), Lactate ([lactate]−), Hexafluorophosphate ([PF6]−) and Nitrate ([NO3]−) anions were investigated theoretically. DFT configurational analysis showed when the anion localized at the top or bottom of cationic imidazolium ring the most stable configuration formed, while locating the anion at the back of imidazolium ring led to the formation of most unstable configuration. Investigation of calculated interaction energies of these molecular configurations showed a similar behavior so that locating the anion at same positions led to the lowest and highest amounts of interaction energies. More detailed analysis indicated that interaction energies of these imidazolium-based ionic liquids depend on hydrogen bond strength, charge transfer energies and electrostatic interactions between cationic and anionic portions. Also scanning the potential energy surface revealed that the modified Buckingham plus Coulomb potential could be used as intermolecular potential energy function between two ionic portions to describe the non-bonded interactions between them.