A Frontier Molecular Orbital Determination of the Active Sites on Dispersed Metal Catalysts

2020 ◽  
pp. 279-292
Author(s):  
Robert L. Augustine ◽  
Konstantinos M. Lahanas
Keyword(s):  
Molecular Orbital ◽  
Active Sites ◽  
Metal Catalysts ◽  
Frontier Molecular Orbital ◽  
Orbital Determination

Comparative analysis of interactions between the hydropyridine dicarboxylate derivatives and different proteins by molecular docking and charge density analysis

2016 ◽  
Vol 15 (06) ◽  
pp. 1650050
Author(s):  
Yanjiao Qi ◽  
Yaming Zhao ◽  
Xiaoe Wang ◽  
Huining Lu ◽  
Nengzhi Jin
Keyword(s):  
Molecular Docking ◽  
Charge Density ◽  
Molecular Orbital ◽  
Drug Target ◽  
Active Sites ◽  
Drug Transport ◽  
Transport Protein ◽  
Target Protein ◽  
Frontier Molecular Orbital ◽  
Density Analysis

Molecular docking and charge density analysis were carried out to understand the geometry, charge density distribution and electrostatic properties of one of newly synthesized 4-substituted-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylates (PDE), which is regarded as the best [Formula: see text]-Glucosidase inhibitor among the hydropyridine dicarboxylate derivatives. The different bonding models of the PDE molecule in the active sites of proteins Human serum albumin (HSA) and Saccharomyces cerevisiae [Formula: see text]-glucosidase (SAG) are firstly compared, which is important to understand the different intermolecular interactions between drug-transport protein and drug-target protein. The deformation density maps suggest that the electron densities of the PDE molecule are redistributed when it presents in the active sites. When the molecule presents in the active site of the SAG, it is evident to find that the negative region does not appear at the vicinity of the oxygen atoms on one of the carboxylic acid dimethyl ester group. Frontier molecular orbital density distributions for the PDE molecule are similar in all forms. The highest occupied molecular orbital (HOMO) and lowest occupied molecular orbital (LUMO) energy gaps in the active sites are higher than that of the molecule in pure solution phase. It is generally noticed that all of the orientations of the dipole moment vectors are reoriented in both active sites. These fine details at electronic level allow to better understand the exact drug-transport protein and drug-target protein interactions.

scholarly journals Synthesis, Single Crystal X-Ray Structure, Hirshfeld Surface Analysis, DFT Computations, Docking Studies on Aurora Kinases and an Anticancer Property of 3-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)-6-methoxy-4H-chromen-4-one

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 413 ◽  
Author(s):  
Seunghyun Ahn ◽  
Jiha Sung ◽  
Ji Hye Lee ◽  
Miri Yoo ◽  
Yoongho Lim ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Surface Analysis ◽  
Active Sites ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Frontier Molecular Orbital ◽  
Monoclinic Space Group ◽  
Term Survival ◽  
X Ray ◽  
Anti Cancer

The isoflavone compound 3-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methoxy-4H-chromen-4-one (6) was prepared and structurally characterized using NMR, mass spectrum and X-ray crystallography. Compound 6, C18H14O5, was crystallized in the monoclinic space group P21/n with the cell parameters; a = 7.1869(4) Å, b = 10.2764(6) Å, c = 19.6771(10) Å, β = 99.442(2)°, V = 1433.57(14) Å3, Z = 4. In the title compound, the chromenone ring system is slightly twisted from planarity and the dihedral angle formed between the plane of the chromenone ring and benzene ring is 47.75°. Several intermolecular hydrogen bonds make the crystal stabilized in the three-dimensional structure, which was confirmed by Hirshfeld surface analysis. Density functional theory (DFT) calculations at the B3LYP/6-311++G(d,p) level were carried out and the calculated geometric parameters were compared with the experimental results. A frontier molecular orbital calculation was performed to reveal that the energy values of highest occupied molecular orbital (HOMO) and lowest un-occupied molecular orbital (LUMO) were −5.8223 eV and −1.8447 eV, and the HOMO–LUMO energy gap was 3.9783 eV. A clonogenic long-term survival assay of compound 6 against HCT116 human colon cancer cells showed an anti-cancer ability, with GI50 value of 24.9 μM. Docking experiments within the active sites of aurora kinase A and B were carried out to explain the anti-cancer property of compound 6.

Theoretical Studies of the Quadratic Polarizabilities of Rigid-Rod Monomers

1988 ◽  
Vol 134 ◽  
Author(s):  
Nelson G. Rondan ◽  
Zenon Lysenko ◽  
Wen-Fang Hwang
Keyword(s):  
Molecular Orbital ◽  
Frontier Molecular Orbital ◽  
Optical Nonlinearities ◽  
Orbital Theory ◽  
Theoretical Determination ◽  
Donor And Acceptor ◽  
Complete Neglect ◽  
Rigid Rod ◽  
Neglect Of Differential Overlap

ABSTRACTOne of the requirements in the theoretical determination of optical nonlinearities is the structure of the molecule. Since most of the molecules that we are interested in examining have not been made, we deemed it necessary to determine their molecular geometries. The structures of 2,6-diphenylbenzo[1,2-d:4,5-d']bisoxazole, 2,6-diphenylbenzo[ 1,2-d:5,4-d']bisoxazole, and 2,2'-p-phenylenebisbenzoxazole, and their corresponding donor- and acceptor-substituted derivatives were determined computationally using the AM1 (Austin Model 1) molecular orbital program. The quadratic polarizabilities (β's) of these model compounds were then computed using the CNDO/S (Complete Neglect of Differential Overlap/ Spectroscopy) program and frontier molecular orbital theory. Results from these calculations will be expounded.

scholarly journals The Effect of Iron Impurities on Transition Metal Catalysts for the Oxygen Evolution Reaction in Alkaline Environment: Activity Mediators or Active Sites?

2020 ◽  
Author(s):  
Ioannis Spanos ◽  
Justus Masa ◽  
Aleksandar Zeradjanin ◽  
Robert Schlögl
Keyword(s):  
Transition Metal ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Water Electrolysis ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Alkaline Water Electrolysis ◽  
Co Catalysts ◽  
Model Transition

AbstractThere is an ongoing debate on elucidating the actual role of Fe impurities in alkaline water electrolysis, acting either as reactivity mediators or as co-catalysts through synergistic interaction with the main catalyst material. This perspective summarizes the most prominent oxygen evolution reaction (OER) mechanisms mostly for Ni-based oxides as model transition metal catalysts and highlights the effect of Fe incorporation on the catalyst surface in the form of impurities originating from the electrolyte or co-precipitated in the catalyst lattice, in modulating the OER reaction kinetics, mechanism and stability. Graphic Abstract

scholarly journals First-Principles Study of Au-Doped InN Monolayer as Adsorbent and Gas Sensing Material for SF6 Decomposed Species

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1708
Author(s):  
Ruochen Peng ◽  
Qu Zhou ◽  
Wen Zeng
Keyword(s):  
Power Systems ◽  
Molecular Orbital ◽  
First Principles ◽  
Recovery Time ◽  
Sulfur Hexafluoride ◽  
Gas Sensing ◽  
Normal Operation ◽  
Frontier Molecular Orbital ◽  
Adsorption System ◽  
Sensing Material

As an insulating medium, sulfur hexafluoride (SF6) is extensively applied to electrical insulation equipment to ensure its normal operation. However, both partial discharge and overheating may cause SF6 to decompose, and then the insulation strength of electrical equipment will be reduced. The adsorption properties and sensing mechanisms of four SF6 decomposed components (HF, SO2, SOF2 and SO2F2) upon an Au-modified InN (Au-InN) monolayer were studied in this work based on first-principles theory. Meanwhile, the adsorption energy (Ead), charge transfer (QT), deformation charge density (DCD), density of states (DOS), frontier molecular orbital and recovery property were calculated. It can be observed that the structures of the SO2, SOF2 and SO2F2 molecules changed significantly after being adsorbed. Meanwhile, the Ead and QT of these three adsorption systems are relatively large, while that of the HF adsorption system is the opposite. These phenomena indicate that Au-InN monolayer has strong adsorption capacity for SO2, SOF2 and SO2F2, and the adsorption can be identified as chemisorption. In addition, through the analysis of frontier molecular orbital, it is found that the conductivity of Au-InN changed significantly after adsorbing SO2, SOF2 and SO2F2. Combined with the analysis of the recovery properties, since the recovery time of SO2 and SO2F2 removal from Au-InN monolayer is still very long at 418 K, Au-InN is more suitable as a scavenger for these two gases rather than as a gas sensor. Since the recovery time of the SOF2 adsorption system is short at 418 K, and the conductivity of the system before and after adsorption changes significantly, Au-InN is an ideal SOF2 gas-sensing material. These results show that Au-InN has broad application prospects as an SO2, SOF2 and SO2F2 scavenger and as a resistive SOF2 sensor, which is of extraordinary meaning to ensure the safe operation of power systems. Our calculations can offer a theoretical basis for further exploration of gas adsorbent and resistive sensors prepared by Au-InN.

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