A molecular dynamics study on aminoacid-based ionic liquids

Abstract

The properties of aminoacid based ionic liquids are studied using classic molecular dynamic simulations. Ionic liquids comprising glycine, serine, alanine and phenyl alanine anions combined with 1-ethyl-3-methylimidazolium, cholinium and N-methylpiperazinium cations are considered. Intermolecular forces, fluids' structuring and dynamic properties were analyzed from a nanoscopic viewpoint. The report showed large interionic hydrogen bonding, both for anion-cation and anion-anion interactions for ionic liquids containing 1-ethyl-3-methylimidazolium cation, with strong effect raising from the anion functional groups. The extension of hydrogen bonding in cholinium-based ionic liquids is almost the half of these in 1-ethyl-3-methylimidazolium ones, but the strength of interactions is equivalent. The intermolecular interactions in piperazinium-based compounds are characterized by strong anion-cation hydrogen bonding leading to the transfer of one of the amino hydrogen atoms from the cation to the anion. This study provides molecular level information on new families of ionic liquids, which can be used for the rational design of ionic liquids regarding to new applications.