A Density Functional Theory Study on the Water Aggregation Behaviour of Fatty-Acid Based Anionic Surface Active Ionic Liquids

2021 ◽  
Author(s):  
Suresh Sampathkumar ◽  
Subramaniam Vijayakumar
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Ionic Liquids ◽  
Fatty Acid ◽  
Water Cluster ◽  
Density Functional ◽  
Water Molecules ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
Aggregation Behaviour

Abstract The hydrogen bond interactions between methyl-imidazolium cation (MIM+) and fatty-acid anions (CmHnCOO–, where m=1–6; n-3–13) of ionic liquids are studied in both gas phase and water phase using density functional theory. The structural properties show that the presence of N–H···O and C–H···O hydrogen bonds between [MIM]+ and [CmHnCOO]– (m=1–6;n-3–13) ionic liquids. From the vibrational frequency analysis it was found that the hydrogen bond interaction between [MIM]+ and [CmHnCOO]– (m=1–6;n-3–13) ionic liquids are red-shifted in frequency. The natural bond orbital analysis show that the N–H···O hydrogen bond associated with the large charge transfer which has the higher stabilization energy (i.e. E(2) ~ 38 kcal/mol). Further, the cation/anion–water cluster (H2O)1-3 interactions show that the water molecules are preferred to interact with anions. In the case of ionic liquids–water cluster interaction, the water molecules occupies the interstitial space between cation and anion of ionic liquids which results in weakening the cation-anion interaction.

scholarly journals Study on the interaction between catechin and cholesterol by the density functional theory

2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Micelle Formation ◽  
Aromatic Rings ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.

INVESTIGATION OF THE INTERACTION OF HYDROXYL AND HYDROPEROXYL RADICALS WITH ETHENE IN THE PRESENCE OF WATER MOLECULES USING COMPUTATIONAL METHODS

2007 ◽  
Vol 06 (02) ◽  
pp. 377-397
Author(s):  
SEIFOLLAH JALILI ◽  
MINA SOLEIMANI
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Computational Methods ◽  
Density Functional ◽  
Atoms In Molecules ◽  
Water Molecules ◽  
Functional Theory ◽  
Aim Theory ◽  
Thermodynamical Parameters ◽  
The Stability

In this work, the interaction of hydroxyl and hydroperoxyl radicals with ethene in the presence of water molecules and the stability of C 2 H 4 + HO x + ( H 2 O )y; x = 1–2, y = 0–5 clusters were investigated using computational methods. Also, hydrogen bond of these clusters was investigated using Density Functional Theory (DFT) and Atoms in Molecules (AIM) theory. Thermodynamical parameters for the interaction of hydroxyl and hydroperoxyl radicals with ethene in the presence of water molecules were also calculated. We report new results for the interaction of hydroxyl and hydroperoxyl radicals with ethene in the presence of water molecules.

scholarly journals Computational Evaluation of Intermolecular Interaction in Poly(Styrene-Maleic Acid)-Water Complexes Using Density Functional Theory

2021 ◽  
Vol 21 (6) ◽  
pp. 1537
Author(s):  
Daru Seto Bagus Anugrah ◽  
Laura Virdy Darmalim ◽  
Permono Adi Putro ◽  
Liana Dewi Nuratikah ◽  
Nurwarrohman Andre Sasongko ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Molecular Orbital ◽  
Maleic Acid ◽  
Density Functional ◽  
Basis Set ◽  
Water Molecules ◽  
Functional Theory ◽  
High Hydrogen

The high application of Poly(styrene-maleic acid) (PSMA) in an aqueous environment, such as biomedical purposes, makes the interaction between PSMA and water molecules interesting to be investigated. This study evaluated the conformation, the hydrogen bond network, and the stabilities of all the possible intermolecular interactions between PSMA with water (PSMA−(H2O)n, n = 1–5). All calculations were executed using the density functional theory (DFT) method at B3LYP functional and the 6–311G** basis set. The energy interaction of PSMA–(H2O)5 complex was –56.66 kcal/mol, which is classified as high hydrogen bond interaction. The Highest Occupied Molecular Orbital (HOMO) – Lowest Unoccupied Molecular Orbital (LUMO) energy gap decreased with the rise in the number of H2O molecules, representing a more reactive complex. The strongest hydrogen bonding in PSMA–(H2O)5 wasformed through the interaction on O72···O17–H49 with stabilizing energy of 50.32 kcal/mol, that analyzed by natural bond orbital (NBO) theory. The quantum theory atoms in molecules (QTAIM) analysis showed that the hydrogen bonding (EHB) value on O72···O17–H49 was –14.95 kcal/mol. All computational data revealed that PSMA had moderate to high interaction with water molecules that indicated the water molecules were easily transported and kept in the PSMA matrix.

Study on Structure Properties of Pyridine Ionic Liquids of Different Acid-Based Chain Lengths

2011 ◽  
Vol 298 ◽  
pp. 51-55 ◽  
Author(s):  
Li Min Wang ◽  
De Qing Chu
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Density Functional ◽  
Pyridine Ring ◽  
Functional Theory ◽  
Chain Lengths ◽  
Chlorine Ion ◽  
Structure Properties

By density functional theory (DFT) at B3LYP/6-311+G** levels, the pyridine ionic liquid with different substituent length has been studied. The calculated results show that the ionic liquid formed by pyridine and a chlorine ion has two main configurations (CCOOH-PyCl and CCOOHPyPCl). There are three combinative locations in each configuration of anion and cation. When the anion is located in the same location, as the acid length becomes longer, the hydrogen bond length between chlorine ion and hydrogen atom in pyridine ring becomes longer, the binding energy between chlorine ion and pyridine with different acid length becomes stronger.

scholarly journals Thermal Stability and Decomposition Kinetics of 1-Alkyl-2,3-Dimethylimidazolium Nitrate Ionic Liquids: TGA and DFT Study

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2560
Author(s):  
Jianwen Meng ◽  
Yong Pan ◽  
Fan Yang ◽  
Yanjun Wang ◽  
Zhongyu Zheng ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Density Functional Theory ◽  
Ionic Liquids ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Nitrogen Atmosphere ◽  
Decomposition Kinetics ◽  
Heating Rates ◽  
Functional Theory ◽  
Kinetics Of

The thermal stability and decomposition kinetics analysis of 1-alkyl-2,3-dimethylimidazole nitrate ionic liquids with different alkyl chains (ethyl, butyl, hexyl, octyl and decyl) were investigated by using isothermal and nonisothermal thermogravimetric analysis combined with thermoanalytical kinetics calculations (Kissinger, Friedman and Flynn-Wall-Ozawa) and density functional theory (DFT) calculations. Isothermal experiments were performed in a nitrogen atmosphere at 240, 250, 260 and 270 °C. In addition, the nonisothermal experiments were carried out in nitrogen and air atmospheres from 30 to 600 °C with heating rates of 5, 10, 15, 20 and 25 °C/min. The results of two heating modes, three activation energy calculations and density functional theory calculations consistently showed that the thermal stability of 1-alkyl-2,3-dimethylimidazolium nitrate ionic liquids decreases with the increasing length of the alkyl chain of the substituent on the cation, and then the thermal hazard increases. This study could provide some guidance for the safety design and use of imidazolium nitrate ionic liquids for engineering.

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