scholarly journals Voltammetric and theoretical studies of electrochemical behavior of cephalosporins at the mercury electrode

2015 ◽  
Vol 80 (8) ◽  
pp. 1035-1049 ◽  
Author(s):  
Katarina Nikolic ◽  
Mara Aleksic ◽  
Vera Kapetanovic ◽  
Danica Agbaba
Keyword(s):  
Density Functional ◽  
Mercury Electrode ◽  
Differential Pulse ◽  
Structure Property ◽  
Qspr Model ◽  
Functional Theory ◽  
Partial Charges ◽  
The Density Functional Theory ◽  
Structure Property Relationship ◽  
Qspr Study

Study of the adsorption and electroreduction behavior of cefpodoxime proxetil, cefotaxime, desacetylcefotaxime, cefetamet, ceftriaxone, ceftazidime, and cefuroxime axetile at the mercury electrode surface has been performed using Cyclic (CV), Differential Pulse (DPV), and Adsorptive Stripping Differential Pulse Voltammetry (AdSDPV). The Quantitative Structure Property Relationship (QSPR) study of the seven cephalosporins adsorption at the mercury electrode has been based on the density functional theory DFT-B3LYP/6-31G (d,p) calculations of molecular orbitals, partial charges and electron densities of analytes. The DFT-parameters and QSPR model explain well the process of adsorption of the examined cephalosporins. QSPR study defined that cefalosporins with lower charge of sulphur in the thiazine moiety, lower electron density on the nitrogen atom of the N-O bond, higher number of hydrogen bond accepting groups, and higher principal moment of inertia should express high adsorption on the mercury electrode.

First principles studies of the interactions between alkali metal elements and oxygen-passivated nanopores in graphene

2018 ◽  
Vol 20 (40) ◽  
pp. 25822-25828 ◽  
Author(s):  
Jonathan J. Heath ◽  
Marcelo A. Kuroda
Keyword(s):  
Alkali Metal ◽  
First Principles ◽  
Density Functional ◽  
Structure Property ◽  
Functional Theory ◽  
Metal Elements ◽  
The Density Functional Theory ◽  
Structural And Electronic Properties ◽  
Structure Property Relationship ◽  
Relationship Of

We characterize the structure–property relationship of alkali metal elements in oxygen-passivated graphene pores using the density functional theory. We identify common trends in these systems based on their structural and electronic properties.

scholarly journals Structure-Property Relationships of 2D Ga/In Chalcogenides

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2188
Author(s):  
Pingping Jiang ◽  
Pascal Boulet ◽  
Marie-Christine Record
Keyword(s):  
Density Functional ◽  
Lattice Mismatch ◽  
Decisive Role ◽  
Interatomic Interaction ◽  
Structure Property ◽  
Functional Theory ◽  
Structure Property Relationships ◽  
Structure Property Relationship ◽  
Maximum Conversion Efficiency

Two-dimensional MX (M = Ga, In; X = S, Se, Te) homo- and heterostructures are of interest in electronics and optoelectronics. Structural, electronic and optical properties of bulk and layered MX and GaX/InX heterostructures have been investigated comprehensively using density functional theory (DFT) calculations. Based on the quantum theory of atoms in molecules, topological analyses of bond degree (BD), bond length (BL) and bond angle (BA) have been detailed for interpreting interatomic interactions, hence the structure–property relationship. The X–X BD correlates linearly with the ratio of local potential and kinetic energy, and decreases as X goes from S to Te. For van der Waals (vdW) homo- and heterostructures of GaX and InX, a cubic relationship between microscopic interatomic interaction and macroscopic electromagnetic behavior has been established firstly relating to weighted absolute BD summation and static dielectric constant. A decisive role of vdW interaction in layer-dependent properties has been identified. The GaX/InX heterostructures have bandgaps in the range 0.23–1.49 eV, absorption coefficients over 10−5 cm−1 and maximum conversion efficiency over 27%. Under strain, discordant BD evolutions are responsible for the exclusively distributed electrons and holes in sublayers of GaX/InX. Meanwhile, the interlayer BA adjustment with lattice mismatch explains the constraint-free lattice of the vdW heterostructure.

Prediction of the half-lives of polychlorinated biphenyls based on the IEF-PCM calculations

2019 ◽  
Vol 18 (07) ◽  
pp. 1950033 ◽  
Author(s):  
Shiyao Liao ◽  
Xinliang Yu ◽  
Jianfang Chen ◽  
Xianwei Huang
Keyword(s):  
Density Functional ◽  
Polychlorinated Biphenyl ◽  
Three Dimensional ◽  
Dft Method ◽  
Polarizable Continuum Model ◽  
Support Vector ◽  
Structure Property ◽  
Qspr Model ◽  
The Density Functional Theory ◽  
Svm Algorithm

Three-dimensional structures of 62 polychlorinated biphenyl (PCB) congeners were optimized with the integral equation formalism polarizable continuum model (IEF-PCM) in combination with the density functional theory (DFT) method at 6-31G(d) level. By applying support vector machine (SVM) algorithm, a nonlinear quantitative structure–property relationship (QSPR) model was built to predict half-lives (log [Formula: see text]) of 62 PCBs in juvenile rainbow trout. The optimal SVM model based on the parameters [Formula: see text] of 854.721 and [Formula: see text] of 0.0565 produces the root-mean-square (rms) errors of 0.0352 for the training set and 0.0446 for the test set, which are less than that of the previous models reported. The results suggest that it is feasible to build SVM models for the half-lives of PCBs with IEF-PCM and B3LYP/6-31G(d) for deriving structural descriptors.

scholarly journals Inhibition of Aluminium Corrosion in 1M HCl by Pyridoxine Hydrochloride: Thermodynamic and Quantum Chemical Studies

2020 ◽  
pp. 20-38
Author(s):  
Mamadou Yeo ◽  
Mougo André Tigori ◽  
Amadou Kouyaté ◽  
Paulin Marius Niamien ◽  
Albert Trokourey
Keyword(s):  
Density Functional ◽  
Activation Parameters ◽  
Structure Property ◽  
Pyridoxine Hydrochloride ◽  
Functional Theory ◽  
Structure Property Relationship ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Increasing Temperature ◽  
Green Corrosion Inhibitors

Currently, research in the area of corrosion inhibition is focussed on the development of green corrosion inhibitors. It is with this in mind that pyridoxine hydrochloride, which is vitamin B6, has been tested as a corrosion inhibitor of aluminium in 1M HCl by mass loss, Density Functional Theory (DFT) and Quantitative Structure-Property Relationship (QSPR) methods. The results obtained show that the inhibition efficiency increases with concentration but decreases with increasing temperature. This vitamin is adsorbed on aluminium according to the modified Langmuir isotherm and occurs in two modes: physisorption and chemisorption. Thermodynamic adsorption and activation parameters have been determined and discussed. Finally, QSPR approach was used to find the best set of parameters in order to determine the theoretical inhibition efficiencies from the experimental data. Experimental measurements were found in good collaboration with the theoretical results.

Anticorrosive properties of theophylline on aluminium corrosion in 1M HCl: Experimental, Computational assessment and synergistic effect iodide ions

2021 ◽  
Vol 11 ◽  
Author(s):  
Tigori Mougo André ◽  
Beda Reginald Henriette Blanche ◽  
Niamien Paulin Marius ◽  
Diabaté Donourou
Keyword(s):  
Density Functional Theory ◽  
Synergistic Effect ◽  
Density Functional ◽  
Inhibition Efficiency ◽  
Quantitative Structure ◽  
Structure Property ◽  
Functional Theory ◽  
Quantitative Structure Property Relationship ◽  
Iodide Ions ◽  
Structure Property Relationship

Aims : The aim of this study is to show the anticorrosive properties of 1,3-dimethyl-7H-purine-2,6-dione on aluminium corrosion in 1M hydrochloric acid and to study the synergy effect between iodide ions and this molecule. Background: Research of eco-friendly, low toxic and biodegradable corrosion inhibitors capable of protecting metals in order to support industrialists who spend large sums of money to replace their corroded equipment. Objective: The main objective is to study the anticorrosive properties of theophylline on aluminium corrosion in 1M HCl. Methods: The anticorrosive properties study of theophylline on aluminium corrosion in 1M HCl was evaluated using mass loss, Density Functional Theory at B3LYP/6-31G (d) and Quantitative Structure-Property Relationship methods. Results: The results obtained show that theophylline inhibition efficiency increases with concentration but decreases with increasing temperature with a maximum value of 88% for 5.10-3M at T = 298 K. The result from absorption isotherms reveals that theophylline adsorbs to the aluminium surface according to the modified Langmuir isotherm. Adejo Ekwenshi's isotherm has shown that the molecule adsorption on aluminium is essentially of a physical nature. Thermodynamic adsorption and activation parameters were calculated and analyzed. A synergistic effect between the molecule studied and the iodide ions was found. Furthermore, global and local reactivity were analyzed through density functional theory calculations. Quantitative structure-property relationship methods model has been permitted to correlate experimental and theoretical inhibition efficiencies. Conclusion: Theophylline is an excellent aluminum inhibitor corrosion in the studied solution. Theoretical results were in agreement with experimental data. Other: Finally to find the best set of parameters for modeling the inhibition efficiency.

scholarly journals Proton transfer reaction confined within carbon nanotubes: Density functional theory and quantitative structure–property relationship analysis

2019 ◽  
Vol 45 ◽  
pp. 146867831986447
Author(s):  
Bilal Achouri ◽  
Yamina Belmiloud ◽  
Meziane Brahimi
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional Theory ◽  
Proton Transfer ◽  
Density Functional ◽  
Quantitative Structure ◽  
Structure Property ◽  
Functional Theory ◽  
Quantitative Structure Property Relationship ◽  
Property Relationship ◽  
Structure Property Relationship

In this work, we focus our attention on chemical reactions confined within carbon nanotubes. As a result of the confinement within carbon nanotubes, novel physical and chemical properties are found for the confined materials. We consider the feasibility of proton transfer inside carbon nanotubes. To do that, we have chosen formamide as the simplest real model for exhibiting the tautomerization in DNA. We have used the quantitative structure–property relationship method, based on geometry optimization and quantum chemical structural descriptors, to illustrate the potential of using the confined space inside carbon nanotubes, which will provide comprehensive information about carbon nanotubes. All calculations have been carried out using density functional theory quantum calculations with the B3LYP functional. The geometries optimized by the Gaussian program were transferred to the computer software DRAGON to calculate pertinent descriptors that could be used in the quantitative structure–property relationship model.

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