QSPR STUDY ON DIRECT PHOTOLYSIS HALF-LIVES OF PAHs IN WATER SURFACE

2005 ◽  
Vol 04 (03) ◽  
pp. 811-822 ◽  
Author(s):  
GUI-NING LU ◽  
ZHI DANG ◽  
XUE-QIN TAO ◽  
PING-AN PENG ◽  
DE-CONG ZHANG
Keyword(s):  
Molecular Orbital ◽  
Water Surface ◽  
Density Functional ◽  
Frontier Molecular Orbital ◽  
Structure Property ◽  
Quantum Chemical Descriptors ◽  
Direct Photolysis ◽  
Qspr Model ◽  
Qspr Modeling ◽  
Qspr Study

Quantitative structure-property relationship (QSPR) modeling is a helpful approach used to correlate the properties of pollutants with their structure descriptors. In this paper a QSPR model for direct photolysis half-lives of polycyclic aromatic hydrocarbons (PAHs) under sunlight on the water surface was developed using density functional theory (DFT) and direct photolysis half-lives of seven PAHs without reported observed values were predicted. The quantum chemical descriptors used in this study were computed at the level of B3LYP/6–311+G(d) and analyzed by partial least squares (PLS) method. The obtained QSPR model with a correlation coefficient of 0.963 was more significant than that derived from semi-empirical molecular orbital algorithm in literatures. It was found that the eigenvalues of the frontier molecular orbital (E HOMO , E LUMO , E NLUMO and E NHOMO ) are important in governing the photolysis half-lives of PAHs in water surface, while the molecular weight (MW) and molecular total energy (TE) also have great effects on photolysis half-lives. The importance of E NLUMO and E NHOMO in the model complicates the photolytic mechanism of PAHs and they might become two useful descriptors in QSPR study on photolysis.

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.

scholarly journals Electron rectification through donor-acceptor-heterocyclics connected to cumulenic bridge: a computational study

2007 ◽  
Vol 5 (3) ◽  
pp. 793-812 ◽  
Author(s):  
J. Laxmikanth Rao
Keyword(s):  
Molecular Electronics ◽  
Molecular Orbital ◽  
Density Functional ◽  
Computational Study ◽  
Potential Drop ◽  
Molecular Wires ◽  
Frontier Molecular Orbital ◽  
Double Bonds ◽  
Acceptor Side ◽  
Donor Acceptor

AbstractDensity Functional Theory (DFT) calculations and Frontier Molecular Orbital (FMO) analysis have been carried out at B3LYP/6-31G(d,p) level of theory on some Donor-Bridge-Acceptor (D-B-A) molecules for their electrical rectification behavior. The donor-acceptor-heterocyclics (D/A-heterocyclics) (namely thiophene, furan and pyrrole rings) are attached as donor and acceptors to the two ends of cumulenic bridge. FMO analysis indicates that the molecules having even number of double bonds in the bridge, possess a complete localization of the MOs i.e., the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are localized on the donor and the acceptor side of the molecules respectively, and LUMO+1 is localized on the donor side, where as in case of odd number of double bonds in the bridge, both the HOMO and LUMOs are delocalized all over the molecule. The Potential Drop (PD) in the former case decreases as the number of double bonds increases in the bridge and due to the presence of the mutually orthogonal and noninteracting π-clouds, they can act as molecular rectifiers. For the molecules with the odd number of double bonds due to the low-lying LUMO delocalized all over the molecule, may find application as molecular wires in molecular electronics circuits.

scholarly journals Crystal Structure, Hirshfeld Surface and Frontier Molecular Orbital Analyses of N-[2-(trifluoromethyl)phenyl]succinamic Acid

2020 ◽  
Vol 32 (12) ◽  
pp. 3179-3185
Author(s):  
P.A. Suchetan ◽  
S. Naveen ◽  
N.K. Lokanath ◽  
P. Krishna Murthy ◽  
M.V. Deepa Urs
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Orbital ◽  
Density Functional ◽  
Hirshfeld Surface ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Reactivity Descriptors ◽  
Succinamic Acid ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The ortho-CF3 substituent and the N-H bond are in syn-conformation in N-[2-(trifluoromethyl)phenyl]succinamic acid. In amide and acid functionalities, the carbonyl groups are directed in opposite directions to each other and their related-CH2 groups. syn-Conformation is observed for the acid functionality, where the carbonyl C=O and hydroxyl O-H bonds are directed in the same direction. Three planar fragments comprise of the molecule: aromatic ring (A), core portion -Carm-N(H)-C(=O)-C(H2)-C(H2)(B) and -C(H2)-C(=O)-OH(C). The dihedral angle between a pair of fragments being 48.6(4)º (A and B), 81.6 (4)º (B and C) and 70.5 (5)º (A and C). N-H•••O hydrogen bonds bind the molecules forming C(4) chains in the crystal, and the neighbouring anti-parallel chains are bound by O-H•••O hydrogen bonds resulting in a chair shaped ribbon of one-dimensional nature. The Hirshfeld surface study was carried out, including fingerprint plots. Studies have shown that the interactions with O•••H/H•••O (27.4%), H•••H (27.3%) and H•••F/F•••H (20.2%) substantially added to the surface. Theoretically, the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and various global reactivity descriptors were also computed by the density functional theory (DFT/B3LYP) approach with a 6-311G(d, p) basis set in the ground state on the geometrically optimized structure in the gas phase.

EFFECT OF ASYMMETRIC LATERAL LINKING GROUPS ON THE ELECTRONIC TRANSPORT IN MOLECULAR DEVICE

2021 ◽  
Author(s):  
YAMIN WU ◽  
BIN LIAO ◽  
GUOLIANG WANG ◽  
BAOAN Bian
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Electronic Transport ◽  
Density Functional ◽  
Molecular Junctions ◽  
Frontier Molecular Orbital ◽  
Asymmetric Distribution ◽  
Molecular Device ◽  
Functional Theory ◽  
Lateral Linking

The effect of asymmetric lateral linking groups on the electronic transport is investigated in the biphenyl molecule-based device with gold electrodes with the framework of density functional theory and nonequilibrium Green’s function. The asymmetric lateral linking groups reduce the currents of molecular junctions, and result in the reverse rectifying behavior. The devices with asymmetric lateral linking groups –SH and –SCH3 have maximum rectifying ratios, while the asymmetric lateral linking group –SH and –NH2 cause minimum rectifying ratios. The calculated results suggest that the asymmetric lateral linking group induces the reduced coupling between molecule and right electrode, asymmetric distribution of frontier molecular orbital and asymmetric evolution of the molecular orbital eigenenergies, accounting for the rectifying behavior.

Study of CXCR4 chemokine receptor inhibitors using QSPR and molecular docking methodologies

2019 ◽  
Vol 18 (04) ◽  
pp. 1950018
Author(s):  
Tahereh Mostashari-Rad ◽  
Roya Arian ◽  
Houri Sadri ◽  
Alireza Mehridehnavi ◽  
Marzieh Mokhtari ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Cancer Metastasis ◽  
Docking Simulation ◽  
Metabolic Stability ◽  
Host Cells ◽  
Structure Property ◽  
Qspr Model ◽  
Cxcr4 Receptor ◽  
Stability And Instability ◽  
Qspr Modeling

CXCR4 is involved in inflammation, cancer metastasis and also HIV-1 entry into immune host cells. In the present research, it was decided to investigate the efficacy of some CXCR4 inhibitors from both pharmacokinetics and pharmacodynamics points of view. Quantitative structure–property relationship (QSPR) approach was applied to model the metabolic stability and instability of the compounds. Using QSPR modeling, it was tried to predict the metabolic stability using new hybrid algorithm which consisted of three different steps: descriptor reduction (PCA), stable–instable classification (KNN) and biological stability prediction (PLS). In the QSPR step, it is shown that the descriptor reduction (PCA) affects the result of the classification procedure (KNN). Besides, the obtained QSPR model can predict the metabolic stability of the stable compounds with [Formula: see text] of 0.98 for train data and of 0.64 for test data. In other words, increment and decrement of stability were followed by the model. Molecular docking simulation was exploited to define the essential interactions of an effective inhibitor with CXCR4 receptor.

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 Synthesis, Antitumor Activity, Oil-Water Partition Coefficient, and Theoretical Calculation of 2 New Rutaecarpine Derivatives With Methoxy Groups

2021 ◽  
Vol 16 (2) ◽  
pp. 1934578X2199168
Author(s):  
Jingjing Ma ◽  
Ruolan Yang ◽  
Hui Guo ◽  
Keyao Zhang ◽  
Jingli Liu ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Frontier Molecular Orbital ◽  
Electron Configuration ◽  
Antitumor Activities ◽  
Methoxy Groups ◽  
Calculation Results ◽  
Oil Water ◽  
Diphenyl Tetrazolium Bromide

Two rutaecarpine (RUT) derivatives, substituted with methoxy groups, namely, 2-methoxyl rutaecarpine (RUT-OCH3, 3a), and 2,10-dimethoxy rutaecarpine (RUT-(OCH3)2, 3b), were synthesized and characterized using 1H nuclear magnetic resonance (NMR), 13C NMR and mass spectra. The in vitro antitumor activities of compounds RUT, 3a, and 3b against A549, H1299, and HepG2 cells were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The results showed that the activity of compounds 3a and 3b was stronger than that of compound RUT, and the activity of compound 3a was stronger than that of 3b, indicating that the activity of the compounds was improved after structural modification. The apparent oil-water partition coefficients of compound RUT, 3a, and 3b were explored using ultraviolet spectrometry. The results indicated that hydrophobicity affects the physicochemical properties of the molecules and influences antitumor activities. In addition, the Natural Electron Configuration, frontier molecular orbital (highest occupied molecular orbital, lowest unoccupied molecular orbital) bandgaps of compounds have been studied based on density functional theory (DFT) by means of DFT-B3LYP/6‐31G (d) in Gaussian 16. The calculation results showed that bandgap of 3a is highest, indicating that the stability of 3a is weakest, so 3a has higher activity than RUT and 3b, which agrees with the results of antitumor activities experiment.

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