The study on interactions between 1-ethyl-3-methylimidazolium chloride and benzene/pyridine /pyrrole/thiophene

The density functional theory was used to investigate the interactions between 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) and benzene/pyridine/pyrrole/thiophene. The complexes formed between [EMIM]Cl and benzene/pyridine/pyrrole/thiophene were optimized at the ωB97XD/6-31++G** level, and the optimized complexes were further analyzed by natural bond orbital, atoms in molecules, and noncovalent interaction. The calculated results show that the interaction energy between ionic liquid and benzene/pyridine/pyrrole/thiophene is in the order pyrrole > pyridine > thiophene > benzene. The major interactions between ionic liquid and benzene/pyridine/pyrrole/thiophene are hydrogen bonding and π-π interaction, accompanied by C···H, N···H, H···H, and S···H weak interactions. Both cation and anion of ionic liquid are involved in interactions with aromatic compounds.