scholarly journals Novel Bis Maleimide Derivatives Containing Azo Group: Synthesis, Corrosion Inhibition, and Theoretical Study

2021 ◽  
Vol 21 (5) ◽  
pp. 1212
Author(s):  
Hawraa Kareem Dhaef ◽  
Rafid Humaidan Al-Asadi ◽  
Ashwaq Abood Shenta ◽  
Mohammed Khalaf Mohammed
Keyword(s):  
Mild Steel ◽  
Density Functional ◽  
Corrosion Inhibitors ◽  
Inhibition Efficiency ◽  
Theoretical Study ◽  
Azo Compounds ◽  
Functional Theory ◽  
Derivatives Of ◽  
Homo Lumo ◽  
Theoretical Results

Novel derivatives of heterocyclic azo compounds have been synthesized through a free catalyst reaction. The structures of the synthesized compounds were confirmed by using different techniques such as 1H-NMR, 13C-NMR, and mass spectroscopy. The prepared derivatives were evaluated as corrosion inhibitors for mild steel after the inhibitory performance toward mild steel in 0.1 M HCl solution. The prepared derivatives, i.e. (1,1'-(((1E,1'E)-1,4-Phenylenebis(diazene-2,1-diyl))bis(4-methyl-3,1-phenylene))bis(1H-pyrrole-2, 5-dione)) 1 and (1,1'-(((1Z,1'Z)-(Oxybis(4,1-phenylene))bis(diazene-2,1-diyl)) bis(4-methyl-3,1-phenylene))bis(1H-pyrrole-2,5-dione)) 2 showed inhibition efficiency 89.22% and 91.30%, respectively at concentration 1 × 10–3 M. The isotherm adsorptions of these derivatives were found to obey Langmuir model. Furthermore, Density functional theory was used for theoretical estimation of the HOMO, LUMO, and other chemical quantum parameters. The results indicated that the synthesized derivatives displayed a corrosive inhibitory property in which derivative 2 was more effective than derivative 1. In addition, the theoretical results were in agreement with the experimental data.

First-Principles Study of Triangle Terarylene as a Possible Optical Molecular Switch

2011 ◽  
Vol 311-313 ◽  
pp. 526-529
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ji Xin Yin
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Molecular Switch ◽  
Optical Switches ◽  
Functional Theory ◽  
Closed Ring ◽  
Potential Applications ◽  
Homo Lumo ◽  
Non Equilibrium Green’S Function ◽  
Theoretical Results

Using non-equilibrium Green’s function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of a triangle terarylene(open- and closed-ring forms) optical molecular switch. The influence of the HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the quantum transport through the molecular device is discussed. Theoretical results show that the conductance of the closed-ring is 3-8 times larger than that of open-ring, which expect that this system can be one of good candidates for optical switches due to this unique advantage, and may have some potential applications in future molecular circuit.

Meso-alkynyl corroles and their cobalt(III), manganese(III) and gallium(III) complexes

2020 ◽  
Vol 24 (05n07) ◽  
pp. 737-749
Author(s):  
Michael Haas ◽  
Sabrina Gonglach ◽  
Wolfgang Schöfberger
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Theoretical Study ◽  
Lumo Energy ◽  
Functional Theory ◽  
Energy Gaps ◽  
Peak Broadening ◽  
Homo And Lumo ◽  
Homo Lumo

We report routes towards synthesis of novel [Formula: see text]-conjugated freebase cobalt, copper, gallium and manganese meso-alkynylcorroles. UV-vis spectra show that extensive peak broadening, red shifts, and changes in the oscillator strength of absorptions increase with the extension of [Formula: see text]-conjugation. Using density functional theory (DFT), we have carried out a first theoretical study of the electronic structure of these metallocorroles. Decreased energy gaps of about 0.3–0.4 eV between the HOMO and LUMO orbitals compared to the corresponding copper, gallium and manganese meso-5,10,15 triphenylcorrole are observed. In all cases, the HOMO energies are nearly unperturbed as the [Formula: see text]-conjugation is expanded. The contraction of the HOMO–LUMO energy gaps is attributed to the lowered LUMO energies.

A Theoretical Study of Carbohydrates as Corrosion Inhibitors of Iron

2013 ◽  
Vol 68 (8-9) ◽  
pp. 581-586 ◽  
Author(s):  
Salim M. Khalil ◽  
Elbashir E. Ali-Shattle ◽  
Nozha M. Ali
Keyword(s):  
Density Functional ◽  
Inhibition Efficiency ◽  
Theoretical Study ◽  
Energy Gap ◽  
Chemical Parameters ◽  
Iron Corrosion ◽  
Electrophilicity Index ◽  
Functional Theory ◽  
Quantum Chemical Parameters ◽  
Highest Occupied Molecular Orbital

The inhibitive effect of fructose, glucose, lactose, maltose, and sucrose against the iron corrosion is investigated using density functional theory at the B3LYP/6-31 G level (d) to search the relation between the molecular structure and corrosion inhibition. The electronic properties such as the energy of the highest occupied molecular orbital (HOMO), the energy of lowest unoccupied orbital (LUMO), the energy gap (LUMO-HOMO), quantum chemical parameters such as hardness, softness, the fraction of the electron transferred, and the electrophilicity index are reported. The inhibition efficiency of the investigated carbohydrates follows the trend: maltose <sucrose<lactose<fructose<glucose.

Theoretical Study of Geometries, Stabilities, and Electronic Properties of Cationic (FeS)n+ (n = 1–5) Clusters

2016 ◽  
Vol 71 (1) ◽  
pp. 45-51 ◽  
Author(s):  
A. Li-Ta ◽  
Zhang Yu ◽  
Bai Jian-Ping ◽  
Zhang Shuai ◽  
Li Gen-Quan ◽  
...  
Keyword(s):  
Density Functional ◽  
Global Minimum ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Binding Energies ◽  
Functional Theory ◽  
Ground State Structures ◽  
Homo Lumo ◽  
Geometric Optimisation ◽  
Theoretical Results

AbstractWe have performed unbiased searches for the global minimum structures of (FeS)n+ (n=1–5) clusters using the CALYPSO method combined with density functional theory geometric optimisation. A large number of low-lying isomers are optimised at the B3PW91/6-311+G* theory level. Accurate ab initio calculations and harmonic vibrational analyses are undertaken to ensure that the optimised geometries are true minimum. They show that the most stable structures begin to exhibit three-dimensional (3D) configurations at n=3. The relative stabilities of (FeS)n+ clusters for the ground-state structures are analysed on the basis of binding energies and HOMO-LUMO gaps. The theoretical results indicate that the binding energies of (FeS)n+ tend to increase with cluster size. The maxima of HOMO-LUMO gaps (3.88 eV) for the most stable configurations appear at (FeS)+. Moreover, we have found that the (FeS)2+ cluster possesses the lowest local magnetic moments compared to the other species. The origin of this magnetic phenomenon is also analysed in detail.

scholarly journals Electrochemical and Theoretical Studies of 2-Acetyl Pyridine and Acetophenone Derivatives as Corrosion Inhibitors for Mild Steel in HCl Solution

2020 ◽  
Vol 32 (12) ◽  
pp. 3097-3104
Author(s):  
Dharmendra Kumar Singh ◽  
Mantu Kr. Singh
Keyword(s):  
Mild Steel ◽  
Density Functional ◽  
Corrosion Inhibitors ◽  
Langmuir Adsorption Isotherm ◽  
Theoretical Studies ◽  
Dft Methods ◽  
Functional Theory ◽  
Langmuir Adsorption ◽  
Acetophenone Derivatives ◽  
Inhibition Ability

2-Acetyl pyridine nicotinic hydrazone and acetophenone nicotinic hydrazone have prepared and their corrosion inhibition properties for mild steel in 1 M HCl were studied using weight loss, electrochemical and density functional theory (DFT) methods. Both inhibitors showed good inhibition ability and their adsorption on mild obeyed Langmuir adsorption isotherm. Polarization measurements show that they can be classified as inhibitors of mixed type. The inhibition efficiencies of 2-acetyl pyridine nicotinic hydrazone and acetophenone nicotinic hydrazone at 2 mM optimum concentration are 96.5% and 87.7% respectively.

Synthesis and Theoretical Study of a Series of 3,5-disubstitutes Pyrazoles

2020 ◽  
Vol 17 (12) ◽  
pp. 932-938
Author(s):  
Karine Braga Enes ◽  
Ana Clara Alves Branco ◽  
Maria Eduarda Toledo Lima ◽  
Marcella Fernandes Mano Mateus ◽  
Luciana Guimaráes ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Chemical Nature ◽  
Theoretical Study ◽  
Energy Gap ◽  
Aromatic Rings ◽  
Frontier Orbitals ◽  
Functional Theory ◽  
Synthesis Yield ◽  
Homo Lumo

In this work, we proposed the synthesis of a series of pyrazoles derivatives with different substituents on the aromatic rings. We aim to evaluate their influence on the reactivity of the compounds in reactions of α,β-unsaturated chalcones and sulfonyl hydrazide catalyzed by iodine. In order to explain their high and low yields, or the impossibility of obtaining some compounds by applied synthetic methodology, Density Functional Theory (DFT) calculations were performed. The reaction Gibbs free energy (ΔG) as well as the energy gap of the HOMO-LUMO frontier orbitals (ΔE) of some selected reactants could explain qualitatively the experimental observations in terms of synthesis yield. In this way, we believe that the chemical nature of aromatic ring substituents is relevant for the reactivity of the starting materials as well as the formation of the desired products.

Hydrogen Bond Interaction of Ascorbic Acid with Urea: Experimental and Theoretical Study

2019 ◽  
Vol 233 (8) ◽  
pp. 1061-1072 ◽  
Author(s):  
Peng Peng ◽  
Ping Zhang ◽  
Huiting Ma ◽  
Cuiping Zhai
Keyword(s):  
Density Functional Theory ◽  
Ascorbic Acid ◽  
Density Functional ◽  
Theoretical Study ◽  
Natural Bond Orbital ◽  
Hydrogen Atoms ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
Interaction Sites ◽  
Theoretical Results

Abstract The interactions of ascorbic acid (AA) with urea were investigated by using the cyclic voltammetry, density functional theory, atoms in molecules and natural bond orbital analyses. The experimental and theoretical results show that the hydrogen bonds are formed between AA and urea, wherein the mainly interaction sites are the hydrogen atoms on enediol of AA and the oxygen atom on carbonyl of urea. The electrochemical behavior of AA was significantly affected by above interactions.

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