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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•Different functional groups in imidazole inhibitors modify the corrosion behavior.•Molecular properties can be associated to corrosion inhibition efficiency.•Theoretical model ...predicts experimental results adequately.
The corrosion inhibition efficiency of carbon steel was evaluated using fifteen molecules derivated from imidazole and benzimidazole in 1.0M HCl. The inhibition efficiency varies from 15.6 to 89.4%, depending on the chemical and the electronic structure of the compounds. The structural properties of the molecules under study were determined by density functional theory. Experimental and theoretical parameters were used to construct a model to predict the inhibition observed. The proposed model shows that inhibition efficiency is related to the molecule volume, charge, electronegativity, and aromaticity. The model is successfully used to predict the corrosion behavior of two additional molecules.
There is no consensus regarding the role of asphaltenes at the oil–water interface. In trying to solve this uncertainty, this work shows for the first time the n-C7 asphaltenes characterization as ...surfactants and polar oil based on the normalized hydrophilic–lipophilic deviation model (HLDN). Interfacial tension (IFT) and interfacial rheological properties of asphaltene/solvent/brine systems at equilibrium were determined. Additionally, stability and electrical conductivity measurements of emulsions obtained from those systems were performed. The results seem to indicate that when the asphaltenes concentration C A in the oil is equal to the critical nanoaggregate concentration (CNAC), the optimum formulation (HLDN = 0) of the system is reached. When C A < CNAC (HLDN < 0), the asphaltenes molecules behave similarly to a slightly hydrophilic nonionic surfactants, while when C A ≫ CNAC (HLDN > 0), asphaltenic clusters have a dual behavior as interfacially active lipophilic aggregates and polar oil.
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.
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).
The synthesis of cis and trans geometrical isomers of platinum( ii ) complexes with a symmetric N-heterocyclic carbene ligand ( Me NHC) is reported. These complexes were obtained from ...1,3-dimethylimidazolium-2-carboxylate, a masked NHC precursor. Their cytotoxicity, oxidative nature, and antibacterial behavior were investigated. The highest cytotoxic effect (IC 50 = 1.21 μM) was observed with the cis -Pt( Me NHC) 2 Cl 2 complex in the cervix cancerous cell line HeLa.
As the installation of solar-photovoltaic and wind-generation systems continue to grow, the location must be strategically selected to maintain a reliable grid. However, such strategies are commonly ...subject to system adequacy constraints, while system security constraints (e.g., frequency stability, voltage limits) are vaguely explored. This may lead to inaccuracies in the optimal placement of the renewables, and thus maximum benefits may not be achieved. In this context, this paper proposes an optimization-based mathematical framework to design a robust distributed generation system, able to keep system stability in a desired range under system perturbance. The optimum placement of wind and solar renewable energies that minimizes the impact on system stability in terms of the standard frequency deviation is obtained through particle swarm optimization, which is developed in Python and executed in PowerFactory-DIgSILENT. The results reveal that the proposed approach has the potential to reduce the influence of disturbances, enhancing critical clearance time before frequency collapse and supporting secure power system operation.
Two series of dinuclear organotin macroheterocycles of general formula R
2
Sn{
Ch
(C
6
H
4
CH
2
)
2
}
2
SnR
2
Ch
= O with R =
n
-Bu (
2a
), Bn (
3a
), Ph (
4a
) and
Ch
= S with R =
n
-Bu (
2b
...), Bn (
3b
), Ph (
4b
) were easily synthetized by a Barbier-type reaction assisted by sonochemical activation of metallic magnesium. The
119
Sn{
1
H} NMR data for all compounds and the X-ray single-crystal diffraction studies for
2a
and
4a
confirmed the presence of a central Sn atom in a four-coordinate environment. The molecular structures of
2a
and
4a
showed puckered 16-membered macroheterocycles. The tin and oxygen atoms are in the interior of the cavity of the macrocycle, surrounded by hydrophobic C–H bonds. A Hirshfeld surface analyses of
2a
and
4a
showed that the macrocycles are linked by weak C–H···π, C···C, and H···H non-covalent interactions. The pairwise interaction energies showed that the cohesion between the macrocycles are mainly due to dispersion forces.
