Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids

Ionic liquids (ILs) or molten salts with melting temperature below 100 °C are highly desirable due to their unique physical and chemical properties which gave them extensive applications ranging from biomedicine, chemical and nuclear industries. Molecular dynamics (MD) simulation can be used to pre...

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Main Author:	Haron, Naimah
Format:	Thesis
Language:	English
Published:	2011
Subjects:	Molecular dynamics - Computer simulation Amino acids Ionic solutions
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spelling	my-upm-ir.196142014-06-30T07:11:22Z Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids 2011-06 Haron, Naimah Ionic liquids (ILs) or molten salts with melting temperature below 100 °C are highly desirable due to their unique physical and chemical properties which gave them extensive applications ranging from biomedicine, chemical and nuclear industries. Molecular dynamics (MD) simulation can be used to predict new molecular structures such as ILs and proteins. In addition, some properties can be predicted by using MD simulation such as density, viscosity and also self-diffusion coefficient. Therefore, MD simulations for three types of amino acid ionic liquids (AAILs), i.e. tetraethylammonium L-glutaminate [N2222][L-Gln], tetraethylammonium Lisoleucinate [N2222][L-Ile] and tetraethylammonium L-lysinate [N2222][L-Lys] have been performed in order to investigate their physical properties. A detailed analysis of the structure and cation-anion interaction in above mentioned AAILs was also provided by Density Functional Theory (DFT) method at B3LYP/6-31G//6-31++G** level. It was shown that the viscosity values of all AAILs derived from molecular dynamics simulations are consistent with the experimental data available. It was also found that the viscosity of AAILs with branched side chain on the amino acid anion such as [N2222][L-Ile] was higher compared to a straight alkyl chain like [N2222][LLys]. In the case of [N2222][L-Gln], the presence of hydrogen bonding donor or acceptor at the side chain of the amino acid anion has increased the viscosity through intermolecular hydrogen bonds between the amino proton and carbonyl oxygen atom. This suggests that the most prominent factor that contributes to the viscosity of AAILs was anions structure. The densities of AAILs from the simulation results were also consistent with experimental. The self-diffusion coefficients, (D) for these three AAILs showed that D[N2222][L-Lys] > D[N2222][L-Ile] > D[N2222][L-Gln] due to its viscosity from lowest to highest. Additionally, the same trend has also been reported by other researchers for Mean Square Displacement (MSD) and D for different ionic liquids. Based on Radial Distribution Function (RDF) results, there were one shoulder peak at 6.00 Å for [N2222][L-Lys] in cation-anion area, which might be due to the tendency of anions distributed from the spherical cation centre. Besides that, this study has shown that each cation was surrounded by seven anions for [N2222][L-Gln] and [N2222][L-Ile] and eight anions for [N2222][L-Lys] according to Spatial Distribution Function (SDF) results. The clear picture of the microstructure details of the important AAILs, which has not yet been systematically investigated in the experimental and theoretical fields can be performed using DFT calculations combined with molecular dynamic simulations. The theoretical results can offer valuable information for the further designing of tetraethylammonium-based ILs. Molecular dynamics - Computer simulation Amino acids Ionic solutions 2011-06 Thesis http://psasir.upm.edu.my/id/eprint/19614/ masters Universiti Putra Malaysia Molecular dynamics - Computer simulation Amino acids Ionic solutions Faculty of Science English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English
topic	Molecular dynamics - Computer simulation Amino acids Ionic solutions
spellingShingle	Molecular dynamics - Computer simulation Amino acids Ionic solutions Haron, Naimah Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids
description	Ionic liquids (ILs) or molten salts with melting temperature below 100 °C are highly desirable due to their unique physical and chemical properties which gave them extensive applications ranging from biomedicine, chemical and nuclear industries. Molecular dynamics (MD) simulation can be used to predict new molecular structures such as ILs and proteins. In addition, some properties can be predicted by using MD simulation such as density, viscosity and also self-diffusion coefficient. Therefore, MD simulations for three types of amino acid ionic liquids (AAILs), i.e. tetraethylammonium L-glutaminate [N2222][L-Gln], tetraethylammonium Lisoleucinate [N2222][L-Ile] and tetraethylammonium L-lysinate [N2222][L-Lys] have been performed in order to investigate their physical properties. A detailed analysis of the structure and cation-anion interaction in above mentioned AAILs was also provided by Density Functional Theory (DFT) method at B3LYP/6-31G//6-31++G** level. It was shown that the viscosity values of all AAILs derived from molecular dynamics simulations are consistent with the experimental data available. It was also found that the viscosity of AAILs with branched side chain on the amino acid anion such as [N2222][L-Ile] was higher compared to a straight alkyl chain like [N2222][LLys]. In the case of [N2222][L-Gln], the presence of hydrogen bonding donor or acceptor at the side chain of the amino acid anion has increased the viscosity through intermolecular hydrogen bonds between the amino proton and carbonyl oxygen atom. This suggests that the most prominent factor that contributes to the viscosity of AAILs was anions structure. The densities of AAILs from the simulation results were also consistent with experimental. The self-diffusion coefficients, (D) for these three AAILs showed that D[N2222][L-Lys] > D[N2222][L-Ile] > D[N2222][L-Gln] due to its viscosity from lowest to highest. Additionally, the same trend has also been reported by other researchers for Mean Square Displacement (MSD) and D for different ionic liquids. Based on Radial Distribution Function (RDF) results, there were one shoulder peak at 6.00 Å for [N2222][L-Lys] in cation-anion area, which might be due to the tendency of anions distributed from the spherical cation centre. Besides that, this study has shown that each cation was surrounded by seven anions for [N2222][L-Gln] and [N2222][L-Ile] and eight anions for [N2222][L-Lys] according to Spatial Distribution Function (SDF) results. The clear picture of the microstructure details of the important AAILs, which has not yet been systematically investigated in the experimental and theoretical fields can be performed using DFT calculations combined with molecular dynamic simulations. The theoretical results can offer valuable information for the further designing of tetraethylammonium-based ILs.
format	Thesis
qualification_level	Master's degree
author	Haron, Naimah
author_facet	Haron, Naimah
author_sort	Haron, Naimah
title	Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids
title_short	Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids
title_full	Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids
title_fullStr	Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids
title_full_unstemmed	Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids
title_sort	molecular dynamics simulation of new tetraethylammonium-based amino acid ionic liquids
granting_institution	Universiti Putra Malaysia
granting_department	Faculty of Science
publishDate	2011
_version_	1747811424844906496

Molecular Dynamics Simulation of New Tetraethylammonium-Based Amino Acid Ionic Liquids

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