Compounds containing carbamate moieties and their derivatives can generate serious public health threats and environmental problems due their high potential toxicity. In this study, a quantitative ...structure–toxicity relationship (QSTR) model has been developed by using one hundred seventy-eight carbamate derivatives whose toxicities in rats (oral administration) have been evaluated. The QSRT model was rigorously validated by using either tested or untested compounds falling within the applicability domain of the model. A structure-based evaluation by docking from a series of carbamates with acetylcholinesterase (AChE) was carried out. The toxicity of carbamates was predicted using physicochemical, structural, and quantum molecular descriptors employing a DFT approach. A statistical treatment was developed; the QSRT model showed a determination coefficient (R2) and a leave-one-out coefficient (Q2LOO) of 0.6584 and 0.6289, respectively.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The relationship between structure and corrosion inhibition of a series of twenty-eight quinoline and pyridine derivatives has been established through the investigation of quantum descriptors ...calculated with PBE/6–311 + + G** method. A quantitative structure–property relationship (QSPR) model was obtained by examining these descriptors using a genetic algorithm approximation method based on a multiple linear regression analysis. The results indicate that the efficiency of corrosion inhibitors is strongly associated with hardness (
η
), minimal electrostatic potential (ESP
min
), and volume (
V
) descriptors. Furthermore, the validity of the proposed model is corroborated by an adsorption study on an iron surface Fe(110).
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The relationship between structure and corrosion inhibition of a series of 30 imidazol, benzimidazol, and pyridine derivatives has been established through the investigation of quantum descriptors ...calculated with PBE/6-311++G**. A quantitative structure–property relationship model was obtained by examination of these descriptors using a genetic functional approximation method based on a multiple linear regression analysis. Our results indicate that the efficiency of corrosion inhibitors is strongly associated with aromaticity, electron donor ability, and molecular volume descriptors. In order to calibrate and validate the proposed model, we performed electrochemical impedance spectroscopy (EIS) studies on imidazole, 2-methylimidazole, benzimidazole, 2-chloromethylbenzimidazole, pyridine, and 2-aminopyridine compounds. The experimental values for efficiency of corrosion inhibition are in good agreement with the estimated values obtained by our model, thus confirming that our approach represents a promising and suitable tool to predict the inhibition of corrosion attributes of nitrogen containing heterocyclic compounds. The adsorption behavior of imidazole or benzimidazole heterocyclic molecules on the Fe(110) surface was also studied to elucidate the inhibition mechanism; the aromaticity played an important role in the adsorbate–surface complex.
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IJS, KILJ, NUK, PNG, UL, UM
The structural and electronic properties were calculated for seventy organic compounds used as dye sensitizers in solar cells, applying the B3LYP exchange-correlation energy functional with the ...6-311G∗∗ basis set. Moreover, the present study proposes two new quantitative structure-property relationship (QSPR) models that enable the prediction of the power conversion efficiency (PCE) and maximum absorption wavelength (λmax) of these systems, the two QSPR models were validated using the coefficient of determination (R2) of 0.62 for both models with the leave-one-out cross-validation correlation coefficient (Q2LOO) of 0.55 and 0.57, respectively. Furthermore, applicability domain analysis was conducted in order to identify the related compounds via the extrapolation of the model.
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•The reactivity of organic compounds is ascertained using Density Functional Reactivity Theory (DFRT).•Quantitative Structure Property Relationship (QSPR) models are used to predict PCE and λmax.•Hardness is found to be an important electronic descriptor for measuring PCE and λmax.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Context
Several descriptors from conceptual density functional theory (cDFT) and the quantum theory of atoms in molecules (QTAIM) were utilized in Random Forest (RF), LASSO, Ridge, Elastic Net (EN), ...and Support Vector Machines (SVM) methods to predict the toxicity (LD
50
) of sixty-two organothiophosphate compounds. The A-RF-G1 and A-RF-G2 models were obtained using the RF method, yielding statistically significant parameters with good performance, as indicated by R
2
values for the training set (R
2
Train
) and R
2
values for the test set (R
2
Test
), around 0.90.
Methods
The molecular structure of all organothiophosphates was optimized via the range-separated hybrid functional ωB97XD with the 6–311 + + G** basis set. Seven hundred and eighty-seven descriptors have been processed using a variety of machine learning algorithms: RF LASSO, Ridge, EN and SVM to generate a predictive model. The properties were obtained with Multiwfn, AIMALL and VMD programs. Docking simulations were performed by using AutoDock 4.2 and LigPlot + programs. All the calculations in this work are carried out in Gaussian 16 program package.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The present study examines bonding patterns between copper Cu
n
clusters (
n
= 3–20) and aromatic compounds (benzene, phenol, and benzaldehyde) using a density-functional theory (DFT) approach. ...Hirshfeld population, natural bond orbital (NBO), molecular orbitals, and quantum theory of atoms in molecules (QTAIM) analyses suggested the formation of two types of interactions Cu–arene and C–H···Cu, in the complexation of copper clusters by an aromatic compound.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A simple, fast and efficient on-line pre-concentration method (large-volume sample stacking) by capillary electrophoresis was proposed for determination of azo dyes residues (allura red AR, sunset ...yellow SY and tartrazine TAR) in water samples. Pre-concentration variables involved in the system were optimised using of a Box-Bhenken design. Under the optimal conditions: injection time 150.0 s, pre-concentration time 120.0 s and reverse potential −8.0 kV, the proposed methodology improved the analytical sensibility achieving limits of detection of 21.0-41.4 µg L
−1
with enrichment factors of 82.1-210.8 fold. The large-volume sample stacking-capillary electrophoresis method was validated and applied to determine azo dyes residues in 20 water samples (bottled, spring and tap water). Two samples were positive for sunset yellow and tartrazine with a concentration of 25.3 and 30.2 µg L
−1
and % RSD less than 10.0% in all cases.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
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•Hydrogen formation between formic acid and Pd4 clusters.•AIM corroborates the pathway theoretical data.•Hydrogen production with natural products using small clusters.•Pd-Pd bond as ...an active site to obtain hydrogen.
A systematic study was conducted on the production of hydrogen from formic acid with a Pd4 cluster using density functional theory (DFT) with the B3LYP and the 6-31G** orbital basis set for the C, H and O atoms, while a LANL2DZ effective core potential was used for palladium atoms. The thermodynamic results obtained show a favorable reaction mechanism for producing hydrogen with energy barriers lower than 30 kcal/mol. Moreover, the nature of the bonds involved in all system were analyzed using the theory of atoms in molecules (AIM) identifying the non-covalent interactions in this type of system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Structural and electronic properties of a series of 25 phosphonate derivatives were analyzed applying density functional theory, with the exchange-correlation functional PBEPBE in combination with ...the 6-311++G** basis set for all atoms. The chemical reactivity of these derivatives has been interpreted using quantum descriptors such as frontier molecular orbitals (HOMO, LUMO), Hirshfeld charges, molecular electrostatic potential, and the dual descriptor
Δ
f
(
r
)
. These descriptors are directly related to experimental median lethal dose (
LD
50
)
, expressed as its decimal logarithm
A
obs
=
log
10
(
LD
50
)
through a multiple linear regression equation. The proposed model predicts the toxicity of phosphonates in function of the volume (
V
), the load of the most electronegative atom of the molecule (
q
), and the eigenvalue of the molecular orbital HOMO (
E
HOMO
)
. The obtained values in the internal validation of the model are:
R
2
=
82.71
%,
R
ADJ
2
=
80.24
%,
F
=
33.5
,
δ
K
=
0.169
,
δ
Q
=
0.011
,
R
P
=
0.423
,
R
N
=
-
0.025
(
-
0.311
)
, and
Q
boot
2
=
75.45
%. The toxicity of nine phosphonate derivatives used as test molecules was adequately predicted by the model. The theoretical results indicate that the oxygen atom of the O=P group plays an important role in the interaction mechanism between the phosphonate and the acetylcholinesterase enzyme, inhibiting the removal of the proton of the ser-200 residue by the his-440 residue.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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•Iodine monolayer formation on the Fe (1 1 0) increases inhibiton efficiency.•Analysis of the inhibition efficiency by EIS corroborates the theoretical data.•The charge density ...difference shows the influence of iodide on corrosion.
The corrosion inhibition by cinnamic, p-coumaric and caffeic acid on carbon steel in 1.0 M HCl and its synergistic combination with KI was investigated using electrochemical and quantum chemical methods. A synergistic effect was observed when 2 mM potassium iodide was added to 0.1 mM inhibitor, where the corrosion inhibition efficiency (IE%) increased from 70% to 80%. In addition, the participation of iodide in the Fe surface was investigated during the adsorption of corrosion inhibitors such as cinnamic, p-coumaric and caffeic acids on Fe(1 1 0). The formation of an iodide monolayer on the Fe(1 1 0) surface was studied by density functional theory (DFT) periodic slab calculations. The DFT results revealed that cinnamic, p-coumaric and caffeic acids were adsorbed effectively on the metal surface through aromatic rings and carboxylic acid groups, as the bond distances with the Fe surface were 2.09 Å for FeC and 1.97 Å for FeO. Low adsorption energies were obtained; −52.90, −44.29 and −33.39 kcal/mol for cinnamic, p-coumaric and caffeic acids, respectively. Additionally, the magnetic moment of the Fe plane was changed significantly if the aromatic carboxylic acid adsorbed onto the metal surface had coating strengths as follows: cinnamic > p-coumaric > caffeic. The present study therefore provides a mechanistic understanding of the role of iodide in the corrosion inhibition process.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
