Molecular Interactions in [PhMT][X] Ionic Liquid: Structures, Binding Energies and Topological Properties

Ionic liquids have attracted significant attention in the literature owing to their ubiquitous applications in diversifying areas of modern chemistry, materials science, and biosciences [1, 2]. The present work focuses on unraveling the molecular interactions underlying [PhMT] [ X] ILs. The hydrogen bond formed between cation phenyl methyl triazolium [PhMT+] and the anions ([X]− = [Cl−], [ClO4−], [CH3CO2−], [CF3CO2−], [NO3−], [N(CN)2−], [N(CN)3−], [NTF2−], [PF6−] and [BF4−]) have been investigated using MP2 method [3] in conjunction with the aug-cc-pVDZ basis set [4]. The structural, binding energy, topological properties of electron density, natural charges and charge transfer values were calculated. Ion pairs (IPs) have electronic binding energies (BEs) in the range of −108.45 to −80.70 kcal/mol at MP2/aug-cc-pVDZ level. The results show that the trend of interactions is IPs [CH3CO2−] [Cl−] [NO3−] [CF3CO2−] [BF4−] [ClO4−] [N(CN)2−] [PF6−] [NTF2−] [N(CN)3−]. The charge analysis was done using natural bond orbital (NBO) analysis. The nature of intermolecular interactions in the [PhMT][X] was characterized by Bader s quantum theory of atoms in molecules (QTAIM) method [5].