scholarly journals Quantum Chemical Investigations of Structural Parameters of PVDF-based Organic Ferroelectric Materials

10.5772/13417 ◽  
2010 ◽  
Author(s):  
Ortiz Elba ◽  
Cuan Angeles ◽  
Norea Luis ◽  
Cortes- Romero ◽  
Wang Qing
Keyword(s):  
Quantum Chemical ◽  
Structural Parameters ◽  
Ferroelectric Materials

Evaluation of Chemotherapeutic Activity of the Selected Bases’ Analogues of Nucleic Acids Supported by ab initio Various Quantum Chemical Calculations

2020 ◽  
Vol 16 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Piotr Kawczak ◽  
Leszek Bober ◽  
Tomasz Bączek
Keyword(s):  
Biological Activity ◽  
Nucleic Acids ◽  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structural Parameters ◽  
Principal Component ◽  
Polarizable Continuum Model ◽  
Activity Data ◽  
Qsar Models

Background: Pharmacological and physicochemical classification of bases’ selected analogues of nucleic acids is proposed in the study. Objective: Structural parameters received by the PCM (Polarizable Continuum Model) with several types of calculation methods for the structures in vacuo and in the aquatic environment together with the huge set of extra molecular descriptors obtained by the professional software and literature values of biological activity were used to search the relationships. Methods: Principal Component Analysis (PCA) together with Factor Analysis (FA) and Multiple Linear Regressions (MLR) as the types of the chemometric approach based on semi-empirical ab initio molecular modeling studies were performed. Results: The equations with statistically significant descriptors were proposed to demonstrate both the common and differentiating characteristics of the bases' analogues of nucleic acids based on the quantum chemical calculations and biological activity data. Conclusion: The obtained QSAR models can be used for predicting and explaining the activity of studied molecules.

Copper macrocyclic complex with trans-di[benzo]-porphyrazine and two oxo ligands: DFT quantum-chemical design

2021 ◽  
pp. A-F
Author(s):  
Oleg V. Mikhailov ◽  
Denis V. Chachkov
Keyword(s):  
Quantum Chemical ◽  
Structural Parameters ◽  
Dft Method ◽  
Nbo Analysis ◽  
Macrocyclic Complex ◽  
Chemical Calculation ◽  
Entropy Formula ◽  
Energy Formula ◽  
Thermodynamic Parameters Of Formation ◽  
Benzo Derivative

Based on the results of a quantum chemical calculation using the DFT method in the OPBE/TZVP and B3PW91/TZVP, the possibility of the existence of a copper heteroligand complex with trans-di[benzo]derivative of 3,7,11,15-tetraazaporphine (trans-di[benzo]porphyrazine) and two oxygen (O[Formula: see text] ions that is still unknown for this element was shown. In addition, the data on the structural parameters, the multiplicity of the ground state, NBO analysis and standard thermodynamic parameters of formation (standard enthalpy [Formula: see text], entropy [Formula: see text] and Gibbs’s energy [Formula: see text] for this complex are presented.

scholarly journals MOLECULAR STRUCTURE OF TRYPTOPHAN: GAS PHASE ELECTRON DIFFRACTION AND QUANTUM-CHEMICAL STUDIES

2020 ◽  
Vol 63 (3) ◽  
pp. 37-45
Author(s):  
Valeriya V. Dunaeva ◽  
Georgiy V. Girichev ◽  
Nina I. Giricheva
Keyword(s):  
Molecular Structure ◽  
Amino Acids ◽  
Electron Diffraction ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Structural Parameters ◽  
Electron Diffraction Data ◽  
Geometrical Parameters ◽  
Intramolecular Hydrogen ◽  
Gas Phase Electron Diffraction

The molecular structure and conformational properties of tryptophan have been investigated by gas-phase electron diffraction and theoretical methods. Quantum chemical calculations realized by program Gaussian 03 (B3LYP/cc-pVTZ) have been predicted the existence of six conformers at the temperature of experiment (T = 495 K). The ability of gas-phase electron diffraction method to distinguish the structure of conformers was estimated theoretically. Conformers have different orientations of carboxylic and amine group, backbone and indole fragment to each other. These conformers can be divided on two groups: distinguishable parameters (with different torsion angle C(OOH)-C(HNH2)-C(H2)-C(ind)) and weekly distinguishable ones (with different torsion angles H-N-C-C and H-O-C-C) by gas-phase electron diffraction. The molecular parameters of the conformers were determined. The conformers have intramolecular hydrogen bonding of the H2N···HO. The analysis of the gas-phase electron diffraction data have been carried out assuming the saturated vapor of tryptophan at T = 495 K consists of mixture at least of two conformers with lowest energy. It was shown that optimal ratio between conformers I : II was 50 : 50, respectively. The geometrical parameters of amino acids molecules (glycine, alanine, tryptophan) obtained by gas-phase electron diffraction were compared. The influence of the intramolecular hydrogen bond was established onto the structural parameters of the backbone of the above amino acids molecules.

scholarly journals Azobenzene/Tetraethyl Ammonium Photochromic Potassium Channel Blockers: Scope and Limitations for Design of Para-Substituted Derivatives with Specific Absorption Band Maxima and Thermal Isomerization Rate

2021 ◽  
Vol 22 (23) ◽  
pp. 13171
Author(s):  
Daniil M. Strashkov ◽  
Vladimir N. Mironov ◽  
Dmitrii M. Nikolaev ◽  
Maxim S. Panov ◽  
Stanislav A. Linnik ◽  
...  
Keyword(s):  
Absorption Band ◽  
Quantum Chemical ◽  
Flash Photolysis ◽  
Structural Parameters ◽  
Kinetic Properties ◽  
Channel Blockers ◽  
Electronic Effects ◽  
Chemical Modeling ◽  
Hammett Constants ◽  
Potassium Channel Blockers

Azobenzene/tetraethyl ammonium photochromic ligands (ATPLs) are photoactive compounds with a large variety of photopharmacological applications such as nociception control or vision restoration. Absorption band maximum and lifetime of the less stable isomer are important characteristics that determine the applicability of ATPLs. Substituents allow to adjust these characteristics in a range limited by the azobenzene/tetraethyl ammonium scaffold. The aim of the current study is to find the scope and limitations for the design of ATPLs with specific spectral and kinetic properties by introducing para substituents with different electronic effects. To perform this task we synthesized ATPLs with various electron acceptor and electron donor functional groups and studied their spectral and kinetic properties using flash photolysis and conventional spectroscopy techniques as well as quantum chemical modeling. As a result, we obtained diagrams that describe correlations between spectral and kinetic properties of ATPLs (absorption maxima of E and Z isomers of ATPLs, the thermal lifetime of their Z form) and both the electronic effect of substituents described by Hammett constants and structural parameters obtained from quantum chemical calculations. The provided results can be used for the design of ATPLs with properties that are optimal for photopharmacological applications.

Structure and bonding of 2,2,2-trichloroethylacetate: An experimental gas phase and computational study

2016 ◽  
Vol 71 (12) ◽  
pp. 1253-1260 ◽  
Author(s):  
Sebastian Blomeyer ◽  
Christian G. Reuter ◽  
Diego M. Gil ◽  
María E. Tuttolomondo ◽  
Aída Ben Altabef ◽  
...  
Keyword(s):  
Gas Phase ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Density Functional ◽  
Dynamic Models ◽  
Computational Study ◽  
Structural Parameters ◽  
Interacting Quantum Atoms ◽  
The One ◽  
Gas Phase Structure

AbstractThe structural and conformational properties of 2,2,2-trichloroethylacetate, H3CCO2CH2CCl3, have been determined in the gas phase using gas electron diffraction (GED). The experimental measurements were complemented by MP2 and DFT quantum-chemical calculations. Two conformers separated by a shallow rotational barrier have been identified, one of C1 (syn-gauche) and the other of Cs symmetry (syn-anti). All calculations indicate that syn-gauche is preferred in terms of enthalpy, whereas syn-anti seems to be slightly more stable regarding Gibbs free energy. In the gas-phase structure determination, dynamic models based on different potential energy surface scans were used. The one from dispersion-corrected density functional theory, predicting a preference of syn-gauche by 1.7kJmol−1, was found to describe the experimental data best. One- and two-conformer models had to be rejected due to correlations and unrealistically large amplitudes. Experimentally determined structural parameters are in good agreement with both, quantum-chemical calculations as well as GED data for related compounds. Interacting quantum atoms (IQA) analyses revealed that interplay between the carbonyl group and the hydrogen as well as chlorine atoms of the trichloroethyl group accounts for most of the stabilisation of the C1 conformer. With intramolecular symmetry-adapted perturbation theory (I-SAPT) analyses it was possible to further elucidate the nature of dominant interactions in the two conformers. Herein, preference of syn-gauche can for the most part be attributed to electrostatic and to some extent to induction and dispersion interplays. In contrast this conformer is severely destabilised through steric repulsion. These results were supported by NBO analyses.

scholarly journals Quantum Chemical Study on the Corrosion Inhibition of Some Oxadiazoles

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Hong Ju ◽  
Li Ding ◽  
Can Sun ◽  
Jie-jing Chen
Keyword(s):  
Mild Steel ◽  
Molecular Orbital ◽  
Quantum Chemical ◽  
Inhibition Efficiency ◽  
Energy Gap ◽  
Structural Parameters ◽  
Quantum Chemical Study ◽  
Dft Method ◽  
Frontier Molecular Orbital ◽  
Acid Media

Quantum chemical calculations based on DFT method were performed on three nitrogen-bearing heterocyclic compounds used as corrosion inhibitors for the mild steel in acid media to determine the relationship between the molecular structure of inhibitors and inhibition efficiency. The structural parameters, such as energy and distribution of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), the charge distribution of the studied inhibitors, the absolute electronegativity (χ) values, and the fraction of electrons (ΔN) transfer from inhibitors to mild steel were also calculated and correlated with inhibition efficiencies. The results showed that the inhibition efficiency of inhibitors increased with the increase in energy of HOMO and decrease in energy gap of frontier molecular orbital, and the areas containing N and O atoms are most possible sites for bonding the steel surface by donating electrons to the mild steel.

Novel oxidation state — zinc(III) in chelate with 3,7,11,15-tetraazaporphine and one fluorine ligand: Quantum-chemical modeling

2019 ◽  
Vol 23 (06) ◽  
pp. 685-689 ◽  
Author(s):  
Oleg V. Mikhailov ◽  
Denis V. Chachkov
Keyword(s):  
Oxidation State ◽  
Quantum Chemical Calculation ◽  
Ground State ◽  
Quantum Chemical ◽  
Structural Parameters ◽  
Dft Method ◽  
Fluoride Ion ◽  
Chemical Calculation ◽  
Chemical Modeling ◽  
The Given

Based on the results of a quantum chemical calculation using the DFT method, the possibility of the existence of a zinc heteroligand complex with 3,7,11,15-tetraazaporphine and fluoride ion with an oxidation state of Zn(III), unusual for the given element, is shown. Data on the structural parameters and multiplicity of the ground state of this complex are also presented.

Determination of thermodynamic functions and structural parameters of NpO2+ lactate complexes

2020 ◽  
Vol 44 (39) ◽  
pp. 17033-17046
Author(s):  
M. M. Maiwald ◽  
K. Müller ◽  
K. Heim ◽  
M. Trumm ◽  
N. L. Banik ◽  
...  
Keyword(s):  
Thermodynamic Functions ◽  
Quantum Chemical ◽  
Structural Parameters ◽  
Quantum Chemical Study ◽  
Chemical Study

This work is a detailed spectroscopic and quantum chemical study on the complexation of Np(v) with the α-hydroxy carboxylate lactate giving information on the complex stoichiometries and thermodynamics (log β, ΔH, ΔS).

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