Geometry optimization of a water molecule in water. A combined quantum chemical and statistical mechanical treatment

<p>This article presents theoretical data on geometric and energetic features of halobenzenes and xylenes. Data were obtained from <i>ab initio</i> geometry optimization and frequency calculations at HF, B3LYP, MP2 and CCSD levels of theory on 6-311++G(d,p) basis set. In total, 1504 structures of halobenzenes, three structures of xylenes and one structure of benzene were generated and processed by custom-made codes in Mathematica. The quantum chemical calculation was completed in Q-Chem software package. Geometric and energetic data of the compounds are presented in this paper as supplementary tables. Raw output files as well as codes and scripts associated with production and extraction of data are also provided.</p>

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Statistical Mechanical Treatment of Adsorbed Monolayer at Electrode/Solution Interface III. The Structure of Inner Layer Formed at the Interface of Hg/(H2O+CH3OH) Solution

Acta Physico-Chimica Sinica ◽

10.3866/pku.whxb19910413 ◽

1991 ◽

Vol 7 (04) ◽

pp. 443-448

Author(s):

Su Wen-Duan ◽

◽

Zhou Shao-Min ◽

Zhou Xiao-Lin

Keyword(s):

Mechanical Treatment ◽

Adsorbed Monolayer ◽

Solution Interface ◽

Statistical Mechanical

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Quantum Chemical Studies and Pharmacophore Modeling for Designing Novel Keap1 Antagonists that Enhance Nrf2 Mediated Neuroprotection

10.26434/chemrxiv.12854927 ◽

2020 ◽

Author(s):

. Srinidhi

Keyword(s):

Quantum Chemical ◽

Density Functional ◽

Developmental Disorders ◽

Interaction Analysis ◽

Geometry Optimization ◽

Pharmacophore Modeling ◽

Docking Studies ◽

Structural Modifications ◽

Antioxidant Mechanism ◽

Chemical Studies

In recent years, the significance of oxidative stress in the pathophysiology of Neurodegenerative/developmental disorders like Attention Deficit Hyperactivity Disorder, Parkinson's and Alzheimer's is being studied at an accelerating pace. Nrf2 activation via Keap1 inhibition is an established strategy for improving the activity of the cellular antioxidant mechanism. In this study, pharmacophore modeling was employed to design efficient Keap1 inhibitors from well-known polypharmacological phytochemicals after extensive structural modifications to improve their pharmacodynamic, pharmacokinetic and drug-likeness qualities (BBB > 0.9, HIA > 0.85). Density functional theory-based quantum chemical calculations at the B3LYP/6-31G (d, p) level of theory were performed for the geometry optimization of the novel ligands and for computing their electronic properties. Resveratrol-4 was found to be the most desirable candidate with an ΔE = 4.24497 eV. HOMO and LUMO distribution of the Resveratrol-4 was found to be very favourable for keap1 binding. Molecular docking studies and comparative interaction analysis also ranked the Resveratrol-4 derivative as the best multi-domain antagonist of the Keap1 protein with a binding affinity of -8 kcal/mole. The following study presents the application of Resveratrol-4 a novel, modified, phytochemical derivative, as an efficient antagonist of the Keap1 protein for enhancing nrf2 mediated neuroprotection from redox insults.

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Kinetics and mechanism of acyl transfer reactions. Part 16. Quantum chemical simulation of mechanism of N-methylaniline sulfonation in aqueous 1,4-dioxane

Butlerov Communications ◽

10.37952/roi-jbc-01/20-61-1-1 ◽

2020 ◽

Vol 61 (1) ◽

pp. 1-8

Author(s):

Ludmila B. Kochetova ◽

◽

Tatiana P. Kustova ◽

Keyword(s):

Water Molecule ◽

Transition State ◽

Reaction Center ◽

Quantum Chemical ◽

Acyl Transfer ◽

Nucleophilic Attack ◽

Quantum Chemical Simulation ◽

Specific Solvation ◽

Benzenesulfonyl Chloride ◽

Chemical Simulation

The RHF/6-31G(d) quantum chemical simulation of the mechanism of the secondary fatty aromatic amine N-methylaniline interaction with benzenesulfonyl chloride under conditions of N-methylaniline specific solvation by one water molecule and one 1,4-dioxane molecule, and under conditions of N-methylaniline specific solvation by two water molecules and one 1,4-dioxane molecule. Three-dimensional potential energy surfaces of the processes pointed out are computed. It is shown that in the both cases a single route of the reactions is realized, starting as an axial nucleophilic attack, which goes further with decreasing of the attack angle as reagent molecules approach each other. It was established that both simulated reactions proceed in accordance with bimolecular concerted mechanism of nucleophilic substitution SN2, which implies the formation of a single transition state in the reaction path. It was found that geometrical configuration of the reaction center in the transition states of the reactions is medium between the trigonal-bipyramidal and tetragonal-pyramidal, which is associated with the change in the angle of N-methylaniline attack as the reactant molecules approach each other. In the benzenesulfonyl chloride reaction with N-methylaniline, solvated by one water molecule and one 1,4-dioxane molecule, the transition state is solvated only by 1,4-dioxane molecule, while water molecule moves away from the reaction center, whereas in the benzenesulfonyl chloride reaction with N-methylaniline, solvated by two water molecule and one 1,4-dioxane molecule the transition state is solvated by 1,4-dioxane molecule and one water molecule that forms hydrogen bond with chlorine atom and promote the S–Cl-bond loosening. The activation energies of the reactions were calculated; it is shown that specific solvation increases the reactions energetic barrier as compared with the reaction in gaseous phase, that is caused by the partial dehydratation of N-methylaniline molecule before the transition state formation. A decrease of the activation energy of the reaction with participation of N-methylaniline, solvated by two water molecule and one 1,4-dioxane molecule as compared with the cases of non-specific solvation of the reactants and N-methyl-aniline solvation by one water molecule and one 1,4-dioxane molecule is caused by the existence of the second water molecule in the system, forming a bond with amine group and facilitating N–H bond break.

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