scholarly journals Practical and Theoretical Study on the Inhibitory Influences of New Azomethine Derivatives Containing an 8-Hydroxyquinoline Moiety for the Corrosion of Carbon Steel in 1 M HCl

2018 ◽  
Vol 34 (6) ◽  
pp. 3016-3029 ◽  
Author(s):  
A. El-Yaktini ◽  
A. Lachiri ◽  
M. El-Faydy ◽  
F. Benhiba ◽  
H. Zarrok ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
Density Functional Theory Method ◽  
Steel Corrosion ◽  
Experimental Results ◽  
Chemical Parameters ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Inhibition Ability

The inhibition ability of a new Azomethine derivatives containing the 8-hydroxyquinoline (BDHQ and MDHQ) towards carbon steel corrosion in HCl solution was studied at various concentrations and temperatures using weight loss, polarization curves and electrochemical impedance spectroscopy (EIS) methods. The experimental results reveal that BDHQ and MDHQ are efficient mixed type corrosion inhibitors, and their inhibition efficiencies increase with increasing concentration. The adsorption of these inhibitors on mild steel surface obeys Langmuir isotherm. Quantum chemical parameters are calculated using the Density Functional Theory method (DFT) and Monte Carlo simulations. Correlation between theoretical and experimental results is discussed.

Study of the Stability and Chemical Reactivity of a Series of Tetrazole Pyrimidine Hybrids by the Density Functional Theory Method (DFT)

2021 ◽  
Vol 37 (4) ◽  
pp. 805-812
Author(s):  
Ahissandonatien Ehouman ◽  
Adjoumanirodrigue Kouakou ◽  
Fatogoma Diarrassouba ◽  
Hakim Abdel Aziz Ouattara ◽  
Paulin Marius Niamien
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Molecular Descriptors ◽  
Chemical Reactivity ◽  
Density Functional Theory Method ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
The Density Functional Theory ◽  
The Stability ◽  
Global Reactivity Descriptors

Our theoretical study of stability and reactivity was carried out on six (06) molecules of a series of pyrimidine tetrazole hybrids (PTH) substituted with H, F, Cl, Br, OCH3 and CH3 atoms and groups of atoms using the density function theory (DFT). Analysis of the thermodynamic formation quantities confirmed the formation and existence of the series of molecules studied. Quantum chemical calculations at the B3LYP / 6-311G (d, p) level of theory determined molecular descriptors. Global reactivity descriptors were also determined and analyzed. Thus, the results showed that the compound PTH_1 is the most stable, and PTH_5 is the most reactive and nucleophilic. Similarly, the compound PTH_4 is the most electrophilic. The analysis of the local descriptors and the boundary molecular orbitals allowed us to identify the preferred atoms for electrophilic and nucleophilic attacks.

Ab Initio Calculations of New α-L5-7a and β-L5-7a Graphyne Polymorphic Varieties

2022 ◽  
Vol 1049 ◽  
pp. 180-185
Author(s):  
Viktor Mavrinskii ◽  
Evgeniy A. Belenkov
Keyword(s):  
Density Functional ◽  
Electronic States ◽  
Density Functional Theory Method ◽  
Geometric Optimization ◽  
Initial Structure ◽  
Functional Theory ◽  
Graphene Layers ◽  
Density Of Electronic States ◽  
Sublimation Energy ◽  
The Density Functional Theory

Calculations of the structural and energy parameters, band structure and density of electronic states of new structural varieties of graphyne have been performed by the density functional theory method. The initial structure of the nine polymorphs was theoretically constructed on the basis of the 5-7a graphene layer. As a result of the calculations, the structure of only five graphyne layers was found to be stable: α-L5-7a, β1-L5-7a, β2-L5-7a, β3-L5-7a and β4-L5-7a. The structure of layers γ1-L5-7a, γ2-L5-7a, and γ3-L5-7a is transformed into the structure of graphene layers by geometric optimization, and the graphyne layer γ4-L5-7a is transformed sp+sp2 layer L3-6-13. The sublimation energy of the stable graphyne polymorphs varies from 6.66 to 6.78 eV/atom. The density of electronic states at the Fermi energy level for all α-L5-7a and β-L5-7a layers of graphyne is different from zero, so the new graphyne polymorphs should have metallic properties.

Hydrogen-Bonded Interactions in the Systems L-Cysteine - H2SeO3 and L-Cysteine -H2SeO4

2013 ◽  
pp. 169-179
Author(s):  
Alexei N. Pankratov ◽  
Nikolay A. Bychkov ◽  
Olga M. Tsivileva
Keyword(s):  
Density Functional ◽  
Density Functional Theory Method ◽  
Thiol Group ◽  
Mutual Orientation ◽  
Theory Method ◽  
Functional Theory ◽  
Compound A ◽  
The Density Functional Theory ◽  
The Enthalpy Of Formation ◽  
Hydrogen Bonded

Using the density functional theory method at the B3LYP/6-31G(d,p) level of theory, the formation of hydrogen-bonded complexes of L-cysteine with selenious and selenic acids has been studied. In both cases of selenium-containing acids, the complexes occur preferably by cysteine carboxylic group, therewith the enthalpy of formation values consist from –19 to –21 kcal/mol, and free energy from –6 to –9 kcal/mol. Probably, the initial act of interaction in the system hydroxyl-containing selenium compound - a-amino acid, proceeding with mutual orientation of the reactants molecules and intermolecular hydrogen bonds formation, serves as a prerequisite for the thiol group capability of participating in the subsequent stages (including more completed transformations) of biologically important reactions.

scholarly journals Proposed Mechanism for the High-Yield Polymerization of Oxyethyl Propiolates with Rh Complex Catalyst Using the Density Functional Theory Method

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 93 ◽  
Author(s):  
Yoshiaki Yoshida ◽  
Yasuteru Mawatari ◽  
Masayoshi Tabata
Keyword(s):  
Density Functional ◽  
Density Functional Theory Method ◽  
High Reactivity ◽  
High Yield ◽  
Complex Catalyst ◽  
Dft Methods ◽  
Functional Theory ◽  
Molecular Weights ◽  
Monomer Structure ◽  
The Density Functional Theory

In this study, poly(oxyethyl propiolate)s (POP)s featuring various oxyethylene derivatives are synthesized using a [Rh(norbornadiene)Cl]2 catalyst. In particular, POPs featuring the normal oxyethylene chain in the side-chain exhibit excellent yields and high molecular weights in methanol and N,N-dimethylformamide at 40 °C, compared with poly(n-alkyl propiolate)s (PnAP)s. The high reactivity of the oxyethyl propiolate (OP) monomers is clarified by considering the time dependences of the polymerization yields of OPs and alkyl propiolates (Aps). Furthermore, the monomer structure and intermediate conformation of the Rh complex are optimized using Density Function theory (DFT) methods (B3LYP/6-31G** and B3LYP/LANL2DZ) and a polymerization mechanism is proposed.

scholarly journals Metastable One-Electron Excited States of Charged Fullerenes

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Rafael V. Arutyunyan ◽  
Alexander D. Vasiliev ◽  
Yuri N. Obukhov ◽  
Alexander V. Osadchy
Keyword(s):  
Density Functional ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Density Functional Theory Method ◽  
Transition Dipole ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Transition Dipole Moments ◽  
Quantum Transitions ◽  
Wavelength Radiation

We study the spontaneous emission processes for the quantum transitions between electron states of a charged C60 fullerene. Lifetimes for the transitions between the volume-localized electron levels and the surface-localized electron levels are evaluated and compared with the transitions between two surface-localized electron levels. We find the lifetimes by computing the transition dipole moments on the basis of the numeric calculations of the three-dimensional electron wave functions of a charged fullerene by making use of the density functional theory method implemented in the QuantumEspresso package. We show that the lifetime of a volume-localized level is of order of 1 μs for a transition energy of about 5 eV. This suggests to consider the possibility of using charged fullerenes for generating short-wavelength radiation, including coherent radiation in this range.

scholarly journals DFT Calculations and Experimental Study to Inhibit Carbon Steel Corrosion in Saline Solution by Quinoline-2-One Derivative

2021 ◽  
Vol 18 (1) ◽  
pp. 0113
Author(s):  
Rehab Majid Kubba ◽  
Mustafa Alaa Mohammed ◽  
Luma S. Ahamed
Keyword(s):  
Carbon Steel ◽  
Density Functional ◽  
Adsorption Mechanism ◽  
Saline Solution ◽  
Physical Adsorption ◽  
Steel Corrosion ◽  
Equilibrium Geometry ◽  
Functional Theory ◽  
Carbon Steel Surface ◽  
Chemical Inhibition

A theoretical and protection study was conducted of the corrosion behavior of carbon steel surface with different concentrations of the derivative (Quinolin-2-one), namly (1-Amino-4,7-dimethyl-6-nitro-1H-quinolin-2-one (ADNQ2O)). Theoretically, Density Functional Theory (DFT) of B3LYP/ 6-311++G (2d, 2p) level was used to calculate the optimized geometry, physical properties and chemical inhibition parameters, with the local reactivity to predict both the reactive centers and to locate the possible sites of nucleophilic and electrophilic attacks, in vacuum, and in two solvents (DMSO and H2O), all at the equilibrium geometry. Experimentally, the inhibition efficiencies (%IE) in the saline solution (of 3.5%) NaCl were studied using potentiometric polarization measurements. The results revealed that the (%IE) for carbon steel corrosion by ADNQ2O is (89.88%). The obtained thermodynamic parameters support the physical adsorption mechanism. The adsorption followed the Langmuir isotherm. The surface change on carbon steel was studied using SEM (Scanning Electron Microscopy).

Hydrogen-Bonded Interactions in the Systems L-Cysteine - H2SeO3 and L-Cysteine -H2SeO4

2011 ◽  
Vol 1 (2) ◽  
pp. 66-76
Author(s):  
Alexei N. Pankratov ◽  
Nikolay A. Bychkov ◽  
Olga M. Tsivileva
Keyword(s):  
Density Functional ◽  
Density Functional Theory Method ◽  
Thiol Group ◽  
Mutual Orientation ◽  
Intermolecular Hydrogen Bonds ◽  
Functional Theory ◽  
Compound A ◽  
The Density Functional Theory ◽  
The Enthalpy Of Formation ◽  
Hydrogen Bonded

Using the density functional theory method at the B3LYP/6-31G(d,p) level of theory, the formation of hydrogen-bonded complexes of L-cysteine with selenious and selenic acids has been studied. In both cases of selenium-containing acids, the complexes occur preferably by cysteine carboxylic group, therewith the enthalpy of formation values consist from –19 to –21 kcal/mol, and free energy from –6 to –9 kcal/mol. Probably, the initial act of interaction in the system hydroxyl-containing selenium compound - a-amino acid, proceeding with mutual orientation of the reactants molecules and intermolecular hydrogen bonds formation, serves as a prerequisite for the thiol group capability of participating in the subsequent stages (including more completed transformations) of biologically important reactions.

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