The present study is aiming to explore the effect of 4-Hydroxy-6-methyl-3-(3-quinolin-8-yl-acryloyl)-pyran-2-one (HMQP) and 3-3-(4-Dimethylamino-phenyl)-acryloyl-4-hydroxy-6-methyl-pyran-2-one ...(DMPHP) on mild steel (MS) corrosion in acid solution (1 M HCl). The compound was tested at various concentrations (0.001–1 mM) and four temperatures (298, 308, 318, and 328 K) to determine the optimal concentration and temperature range for the best corrosion inhibiting effect. In evaluating the inhibition efficiency, weight loss measurement, potentiodynamic polarization measurement (PDP), electrochemical impedance spectroscopy, SEM/EDS and theoretical methods were used. The inhibition efficiencies increase with increase in concentration and decreases with temperature. The maximum inhibition efficiency was found 90% and 85.4% at 298 K in the presence of 1 mM of DMPHP and HMQP respectively. The experimental adsorption data obeyed the Langmuir isotherm model. The polarization parameters suggest that DMPHP and HMQP are mixed type inhibitors. The results of the EIS study suggest that these compounds inhibit corrosion by adsorption mechanism. A good correlation between theoretical and experimental results was obtained.
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•Inhibition effect of new pyran derivatives for mild steel corrosion has been studied.•Adsorption of both inhibitors follows a Langmuir isotherm.•SEM and EDS were performed for surface study.•The experimental results were well supported by DFT and Monte Carlo simulation.
In this paper, we report the synthesis of new unsymmetrical azines Schiff bases. These compounds were prepared by condensation of hydrazine with different aldehydes and ketones to give (E) ...-2-hydroxynaphthalene-1-carbaldehyde (1E) -2-thienylmethylene hydrazone compound (I) and (Z) - 2 - (E) -1- (2-hydroxyphenyl) ethylidenehydrazin-1-ylidene -1,2-diphenylethanone compound (II). The method adopted consists in reacting the two different carbonyl compounds simultaneously in one step in a stepwise manner reported which is practical and cost-effective. The reaction with a minor modification in operating conditions proceeded efficiently and with excellent performance. The structure of each of the two compounds (I) and (II) was determined by the X-ray diffraction technique performed on single crystals. The asymmetric unity of the two molecules consists of one asymmetry-independent molecule. In addition, hydrogen bonds CH … π are observed in the compound (II). We then present a detailed DFT study based on B3LYP/6-31G (d, p) geometric structures of compounds (I); (II) and another compound (III) also another asymmetric azine (Z) -2 - (E) -2-benzylidenehydrazine-1-ylidene -1,2-diphenylethanone whose crystal structure is reported. The fundamental vibration wave numbers are calculated and a good agreement between the observed and calculated wave numbers is obtained. The study was extended to the HOMO-LUMO analysis to calculate the energy gap. The calculated HOMO and LUMO energy reveals that the charge is transferred into the molecule.
•The synthesis of new unsymmetrical Schiff bases is reported.•Three new hydrazine are characterized through UV–Vis, FT-IR, and X-ray analysis.•Calculated UV–vis absorption in excellent agreement with the experimental data.
Symmetrical azine ligand-based (L1-L6) have been evaluated for their catecholase activity by combining them in situ with different metal salts, the complexes exhibited significant catalytic activity ...in oxidizing catechol to o-quinone at ambient conditions in the presence of dioxygen as an oxidant, especially for the combination of L4/CuCl2 with molar ratio 1L/1M with Vmax of 50,24 μmol L−1 min−1 and with Km equal to 0,0215 mol L−1, the study showed that several parameters are contributed on the catalytic activity of mimicking enzymes such as the nature of Ligand, ion metal, counter anion, the concentration of ligand and substrate. Kinetic parameters have been determined for the best combinations following the Michaelis Menten and the results obtained are in agreement with this model.
Two novel pyran-2-one derivatives, namely (E)-4-hydroxy-6-methyl-3-(1-(phenylimino) ethyl)-2H-pyran-2-one (Py1) and (E)-3-(1-((2-chlorophenyl)imino)ethyl)-4-hydroxy-6-methyl-2H-pyran-2-one (Py2) were ...evaluated for corrosion inhibition performance on mild steel (MS) in 1M HCl via potentiodynamic polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS). The experimental results show that the inhibition increases with the concentration and can reach a limit value of 90.0% for the inhibitor Py1 at 10−3 M. The polarization curves offer that the pyran-2-one derivatives (Py1 and Py2) are of mixed type. The increase in temperature may have a decrease in the inhibition efficacy of the compounds studied. In addition, the thermodynamic studies show that the inhibitors adsorbed on the surface with chemical bonds (chemisorption) and according to the Langmuir isotherm, the DFT calculations show a good fit to the experimental data.
In the structure of the mononuclear title complex, Cu(C8H7O4)2(C2H6OS)2, the CuII atom lies on an inversion centre and has an octahedral coordination geometry of type MO6. The bidentate ...dehydroacetic acid (DHA) ligands occupy the equatorial plane of the complex in a trans configuration, and the dimethylsulfoxide (DMSO) ligands are weakly coordinated through their O atoms.
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