Molecular structure, reorientational dynamics, and intermolecular interactions in the neat ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

2004 ◽  
Vol 76 (1) ◽  
pp. 255-261 ◽  
Author(s):  
J. H. Antony ◽  
D. Mertens ◽  
Tobias Breitenstein ◽  
Andreas Dölle ◽  
P. Wasserscheid ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Hydrogen Bonding ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Ion Pairs ◽  
Md Simulations ◽  
Liquid Structure ◽  
Distribution Functions ◽  
Reorientational Dynamics ◽  
Pair Distribution Functions

Results on the molecular and liquid structure and the reorientational dynamics are reported for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). In quantum-chemical calculations for [BMIM][PF6] in the gas phase, hydrogen bonding between the proton at carbon 2 in the aromatic ring and the fluorine atoms of the hexafluorophosphate anion was found. From the analysis of 13C relaxation data, the reorientational motions were evaluated, and the Vogel-Fulcher-Tammann and Arrhenius activation energies for the overall and internal reorientational motions, respectively, of the different 13C-1H vectors are given as well as correlation times at 300 K. By performing molecular dynamics (MD) simulations, pair distribution functions between moieties in the cation and the phosphorous atom in the anion were determined. The pair distribution function for the proton at carbon 2 exhibits a particular sharp and strong maximum indicating a strong interaction with the anion. The quantum-chemical calculations, the motional parameters, and the results from the MD simulations support the existence of hydrogen bonding and the formation of ion pairs in the ionic liquid.

Hydrogen-Bonding and the Dissolution Mechanism of Uracil in an Acetate Ionic Liquid: New Insights from NMR Spectroscopy and Quantum Chemical Calculations

2013 ◽  
Vol 117 (15) ◽  
pp. 4109-4120 ◽  
Author(s):  
João M. M. Araújo ◽  
Ana B. Pereiro ◽  
José N. Canongia Lopes ◽  
Luís P. N. Rebelo ◽  
Isabel M. Marrucho
Keyword(s):  
Ionic Liquid ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Dissolution Mechanism

scholarly journals Investigation of Microscopic Structure and Ion Dynamics in Liquid Li(Na, K)EutecticCl Systems by Molecular Dynamics Simulation

2018 ◽  
Vol 8 (10) ◽  
pp. 1874 ◽  
Author(s):  
Jie Wu ◽  
Jia Wang ◽  
Haiou Ni ◽  
Guimin Lu ◽  
Jianguo Yu
Keyword(s):  
Molecular Dynamics ◽  
Ionic Conductivity ◽  
Shear Viscosity ◽  
Ion Pairs ◽  
Liquid Structure ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Molten Chloride ◽  
Ion Clusters ◽  
Self Diffusion

Molten chloride salts are the main components in liquid metal batteries, high-temperature heat storage materials, heat transfer mediums, and metal electrolytes. In this paper, interest is centered on the influence of the LiCl component and temperature on the local structure and transport properties of the molten LiCl-NaCl-KCl system over the temperature range of 900 K to 1200 K. The liquid structure and properties have been studied across the full composition range by molecular dynamics (MD) simulation of a sufficient length to collect reliable values, such as the partial radial distribution function, angular distribution functions, coordination numbers distribution, density, self-diffusion coefficient, ionic conductivity, and shear viscosity. Densities obtained from simulations were underestimated by an average 5.7% of the experimental values. Shear viscosities and ionic conductivity were in good agreement with the experimental data. The association of all ion pairs (except for Li-Li and Cl-Cl) was weakened by an increasing LiCl concentration. Ion clusters were formed in liquids with increasing temperatures. The self-diffusion coefficients and ionic conductivity showed positive dependences on both LiCl concentration and temperature, however, the shear viscosity was the opposite. By analyzing the hydrodynamic radii of each ion and the coordination stability of cation-anion pairs, it was speculated that ion clusters could be the cation-anion coordinated structure and affected the macro properties.

Weak intramolecular and intermolecular hydrogen bonding of benzyl alcohol, 2-phenylethanol and 2-phenylethylamine in the adsorption on graphitized thermal carbon black

2015 ◽  
Vol 17 (37) ◽  
pp. 24282-24293 ◽  
Author(s):  
V. V. Varfolomeeva ◽  
A. V. Terentev
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Carbon Black ◽  
Benzyl Alcohol ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Intermolecular Hydrogen Bonding ◽  
Weak Hydrogen Bond ◽  
Graphitized Thermal Carbon Black ◽  
Flexible Molecules

The present paper discusses the contemporary state of the studies of the weak hydrogen bond contribution to the adsorption of flexible molecules. We formulated the problems which can be solved today only using the NCI method and quantum chemical calculations.

scholarly journals Understanding the ionic liquid [NC4111][NTf2] from individual building blocks: an IR-spectroscopic study

2015 ◽  
Vol 17 (13) ◽  
pp. 8518-8529 ◽  
Author(s):  
Kenny Hanke ◽  
Matin Kaufmann ◽  
Gerhard Schwaab ◽  
Martina Havenith ◽  
Conrad T. Wolke ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Spectroscopic Study ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Molecular Level ◽  
Building Blocks ◽  
Spectroscopic Methods ◽  
Ir Spectroscopic

This study uses complementary spectroscopic methods in combination with quantum chemical calculations to explore at a molecular level the ionic liquid [NC4111][NTf2] from single ions to the bulk.

Problems with a conformation assignment of aryl-substituted resorc[4]arenes

2011 ◽  
Vol 76 (10) ◽  
pp. 1199-1222 ◽  
Author(s):  
Jakub Kaminský ◽  
Hana Dvořáková ◽  
Jan Štursa ◽  
Jitka Moravcová
Keyword(s):  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Quantum Chemical Calculations ◽  
Dynamic Process ◽  
Quantum Chemical ◽  
Energy Barrier ◽  
Π Interactions ◽  
Temperature Range ◽  
Acid Catalyzed

Acid-catalyzed condensation of resorcinol with 3,5-diisopropoxybenzaldehyde and 3,5-dihydroxybenzaldehyde afforded aryl substituted resorc[4]arenes 1a and 1b, respectively. All 16 hydroxyls in 1b were acetylated providing resorc[4]arene 1c. The conformational behaviour of 1a, 1b and 1c was studied by NMR spectroscopy and quantum chemical calculations. It was found that the stabilization of their conformations is an effect of competing π-π and OH-π interactions, hydrogen bonding and steric features, respectively. As a result, C2 symmetrical boat conformations 1a, 1b and 1c with aryls in axial positions were identified in all cases. In case of 1c also the formation of C2 symmetrical conformation with aryls in equatorial positions (boat-eq) was identified. Moreover, compounds 1a and 1b being able to create hydrogen bonds, adopt also symmetrical C4 crown conformations. For 1c(boat-ax), the boat-boat conversion with energy barrier of 80 kJ/mol was observed, while the 1c(boat-eq) was found to be rigid in the whole accessible temperature range. Both conformers of 1c exhibit also second dynamic process – rotation of bridge aryl rings (ΔG‡ = 66 kJ/mol).

scholarly journals Mechanisms of Deamidation of Asparagine Residues and Effects of Main-Chain Conformation on Activation Energy

2020 ◽  
Vol 21 (19) ◽  
pp. 7035
Author(s):  
Koichi Kato ◽  
Tomoki Nakayoshi ◽  
Eiji Kurimoto ◽  
Akifumi Oda
Keyword(s):  
Activation Energy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Density Functional ◽  
Main Chain ◽  
Density Functional Method ◽  
Md Simulations ◽  
Chain Conformation ◽  
Dihydrogen Phosphate ◽  
Chain Conformations

Deamidation of asparagine (Asn) residues is a nonenzymatic post-translational modification of proteins. Asn deamidation is associated with pathogenesis of age-related diseases and hypofunction of monoclonal antibodies. Deamidation rate is known to be affected by the residue following Asn on the carboxyl side and by secondary structure. Information about main-chain conformation of Asn residues is necessary to accurately predict deamidation rate. In this study, the effect of main-chain conformation of Asn residues on deamidation rate was computationally investigated using molecular dynamics (MD) simulations and quantum chemical calculations. The results of MD simulations for γS-crystallin suggested that frequently deamidated Asn residues have common main-chain conformations on the N-terminal side. Based on the simulated structure, initial structures for the quantum chemical calculations were constructed and optimized geometries were obtained using the B3LYP density functional method. Structures that were frequently deamidated had a lower activation energy barrier than that of the little deamidated structure. We also showed that dihydrogen phosphate and bicarbonate ions are important catalysts for deamidation of Asn residues.

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