Theoretical Study on Amino Acid-Based Ionic Pairs and Their Interaction with Carbon Nanostructures

Abstract

Quantum chemistry methods were used to analyze the properties of ionic pairs formed by combination of the 1-ethyl-3-methylimidazolium cation with anions derived from alanine, glycine, serine, and phenylalanine amino acids, which appear in the corresponding ionic liquids. Anion−cation pairs were studied from structural and energetic viewpoints using density functional theory together with the use of natural bond orbital and atoms in a molecule approaches. Interactions of the mentioned ionic pairs with carbon nanostructures carried out with graphene sheets and single-walled carbon nanotubes, with ions placed on the outer surface and when confined inside the nanotube, were analyzed from first principles. Interaction energies, density of states, and charge density allow inferring the mechanism of interaction between the ion pairs and graphene or carbon nanotubes.

Adsorption of choline benzoate ionic liquid on graphene, silicene, germanene and boron-nitride nanosheets: a DFT perspective

“…2,4,5 Because of its remarkable properties, graphene-based applications have been reported in a wide range of areas, such as optoelectronic devices, energy generation, chemical sensors, or hybrid materials. [6][7][8] Among the wide variety of molecules which could be absorbed on graphene surface, a very relevant field of study is the interaction of ionic liquids (ILs) with carbon nanostructures and their behavior with regard the carbon nanostructure, because of its importance both for basic science and for applied purposes. 6 The mechanism of adsorption of relevant molecules, and also the changes in graphene properties upon molecular adsorption have been widely studied both using experimental and computational approaches.…”

“…1, 2, 4 Likewise, the potential applications of graphene can be extended and task-specific tuned through the functionalization (or chemical absorption) of molecules and nanoparticles. [8][9][10][11][12] ILs are emerging as an attractive alternative to conventional organic solvents due to their especial chemical and physical properties: negligible vapor pressures, high thermal and chemical stability, non flammability or good solvent capacity for a wide range of organic, inorganic, polymeric and organometalic compounds, and the possibility of designing taskspecific ILs through the suitable combination of cations and anions. [6][7][8] Among the wide variety of molecules which could be absorbed on graphene surface, a very relevant field of study is the interaction of ionic liquids (ILs) with carbon nanostructures and their behavior with regard the carbon nanostructure, because of its importance both for basic science and for applied purposes.…”

“…[8][9][10][11][12] ILs are emerging as an attractive alternative to conventional organic solvents due to their especial chemical and physical properties: negligible vapor pressures, high thermal and chemical stability, non flammability or good solvent capacity for a wide range of organic, inorganic, polymeric and organometalic compounds, and the possibility of designing taskspecific ILs through the suitable combination of cations and anions. 8,10,12,15 As matter of fact, both theoretical and experimental studies have been conducted to elucidate the mechanism of interaction between ILs and graphene. 14 In addition, the behavior of ILs with regard to graphene surfaces have also been studied, both using experimental and theoretical approaches, which have led to propose relevant applications in several technological fields, such as full cells, supercapacitors, solar cells or storage devices.…”

“…13 Therefore, ILs have been considered for applications in different technological fields such as lubrication, solvents extraction, catalytic processes or electrochemical applications. 8,10,11,15,16,17 Nevertheless, most available studies are limited to a reduced number of classic types of ILs, such as imidazol based ionic liquids. 8,10,12,15 As matter of fact, both theoretical and experimental studies have been conducted to elucidate the mechanism of interaction between ILs and graphene.…”

“…1, 19 Nonetheless, some remarkable differences should be noted between C and Si/Ge based nanosheets. 8,10,11,15,16,17 As previously noted, those works, are mainly limited to classic ILs. 1, 19,20 In silicene / germanene sheet, silicon / germanium owns sp 3 hybridization, which is the most favorable configuration in comparison with the sp 2 or the mixed sp 2 -sp 3 orbitals.…”