Interaction between nanostructured tetrazolium based ionic liquids and aromatic sulfur compounds: A M062X functional approach

Density functional theory has been used to investigate the interactions between aromatic sulfurcompounds (dibenzothiophene, diphenylsulfide and thiophene) and nanostructured ionic liquid 1-ethyl-3-methyltetrazolium tetrafluoroborate ([EMTT][BF4]). The M062X functional and 6-311++G(d,p) basis set wereemployed for optimization of structures in the gas phase. The natural bond orbital analysis (NBO) and thequantum theory of atoms in molecules (AIM) have been employed to elucidate the interaction characteristicsbetween the 1-ethyl-3-methyltetrazolium tetrafluoroborate ionic liquid and aromatic sulfur compounds. Resultshave demonstrated that both cation and anion in ionic liquid play the important roles in extraction and separationof aromatic sulfur compounds. The interaction energy between ionic liquid and sulfur compounds decreases inthe following order: diphenylsulfide  thiophene  dibenzothiophene. The charge analysis reveals that there is acharge transfer during the process. The AIM results confirm the existence of hydrogen bonding between thearomatic sulfur compounds and the ionic liquid.

Keywords:

Density functional theory , Hydrogen bonding , Ionic liquid , NBO