Mn(II), Fe(III),Co(II), Ni(II) and Cu(II) complexes of the ligand named (3-Cyano-6-thiophen-2-yl[4,4′]bipyridinyl-2-yloxy)-acetic acid hydrazide (abbreviated as HL) have been synthesized. Structure assignment of such chelates have been performed by means of analytical and spectral tools which joint assured the formulation of the chelates in 1 M: 1 L ratio with non-electrolytic character for all the complexes. Fe(III) complex is 1:3 electrolyte. The spectral IR toll proved the neutral tridentate ligand nature connecting to the metal ions by the azomethine nitrogen, carbonyl and ester oxygen atoms. Octahedral structure has been concluded for all the isolated chelates as deduced from the UV-Vis spectral analysis. The investigated complexes were tested to protect or restrain the corrosion of copper in 1.0 M HCl solution at 298 K using different techniques. The outcomes being acquired illuminated that the synthesized compounds were discovered to be efficient inhibitors and their % IEs were concluded to be dependent on both concentrations and structures. The order of the % IEs of the tested compounds was: HL-Mn > HL-Fe > HL-Co ≥ HL- Ni > HL-Cu > HL. The acquired high % IEs were ascribed to the powerful adsorption of the organic molecules on the surface of copper which was agreed with Langmuir adsorption isotherm. The kinetics of corrosion inhibition by the examined compounds appeared negative-first order process. PDP results indicated that the complex HL-Mn behaves as a mixed-kind inhibitor with slight anodic seniority. The employed techniques used for the complex HL-Mn were in a good consistence with each other.

Pyrazolones are a class of heterocyclic compounds that contain a pyrazole ring fused to a ketone group. Recent scientific research has focused extensively on the potential anti-inflammatory properties of pyrazolone compounds due to their diverse pharmacological effects in alleviating inflammation and reducing fever. This motivated us to focus on the preparation of these derivatives in a simple and eco-friendly manner. A convenient new green methodology was modified for the preparation of 1-phenyl-3,5-pyrazolidinedione by the sonicated MCR of diethyl malonate, phenylhydrazine, and a catalytic amount imidazole as homogenous organic catalyst in water green solvent in a good yield. On the other hand, some of 4-arylidinepyrazolidinedione derivatives are prepared in the same manner via the treatment of a mixture of diethyl malonate, phenylhydrazine, aromatic aldehydes, and a catalytic amount of imidazole in an aqueous medium. Our target synthesized pyrazolidinediones were elucidated via elemental and several spectral analyses. Due to the importance of pyrazolidinediones in the field of treating inflammation and relieving pain, a number of prepared compounds were chosen to test their efficacy as anti-inflammatory agents using carrageenan-induced foot edema in rats and compare the results with indomethacin, the standard drug. We found that the majority of derivatives yield promising results spanning from good to wonderful, so derivatives (15k, 15b, 15h, 15a, and 15j) yield the best results while derivative (15i) yields an average result. As for the derivative (15f), it yields the lowest results compared to the standard drug. This is due to the difference in the structural composition of these derivatives, which increases the likelihood of their use as antiinflammatory derivatives.

The condensation reaction of bis-oxindole with aniline derivatives produced three derivatives of 1,1-(propane-1,3-diyl)bis(3-(substitutedphenylimino)-indoline-2-one). In addition, one spiro-triazole-oxindole derivative was created by 1,3-dipolar cycloaddition of hydrazonoyl chloride on the C¼ N of the latter Schiff base. The spectral analyses of these bis-oxindole/spiro-triazole-oxindole series proved their structure. The four synthesized bis-oxindole/bis-spiro-triazole-oxindoles, denoted 3a, 3b, 3c, and 6, were tested as copper corrosion inhibitors in 1.0 M H2SO4 at 298 K. For all studied organic compounds, weight loss (WL) was used; electrochemical techniques (potentodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS)) were used for the compound with the highest inhibition efficiency (% IE). The current findings revealed that the tested compounds were determined to be effective inhibitors, and their% IEs were discovered to be dependent on their concentrations and structures. At the same concentrations, the WL results revealed that the order of the% IEs of the tested compounds was: 3a 3c 3b 6 (compound 6 was found to have the highest% IE). The examined compounds’ high IEs are attributed to the forceful adsorption of such molecules on the copper surface, which results in the formation of an adhered protecting layer. Such adsorption was discovered to follow the Langmuir adsorption isotherm. The kinetics of corrosion inhibition by the investigated compounds revealed a negative-first order process, supporting the obtained high% IEs. According to PDP results, compound 6 behaves as a mixed inhibitor with a cathodic majority. The collected results for the compound 6 regarding the values of % IEs obtained via the three employed techniques were compared and designated a good concordance between all utilized techniques.

This paper investigates the performances of two synthesized formamidine derivatives, namely: N,N-dimethyl-N’- (pyridin-2-yl) formamidine (A) and N,N-dimethyl-N’-(pyrimidin-2-yl) formamidine (B) to inhibit the corrosion of copper in 1.0 M HNO3 solution at fixed temperatures. Different tools, viz. electrochemical, chemical, and microscopic techniques were utilized in this paper. The evaluated inhibition efficiencies (% IEs) of the tested formamidine derivatives increased with their concentrations. Results indicated that the tested compounds acted as mixed-kind inhibitors with anodic seniority. The acquired great% IEs of such compounds were mainly attributed to the strong adsorption of the compounds’ molecules on the copper surface. The mode of adsorption was agreed with Langmuir isotherm. The results acquired from all utilized tools agreed with each other which disclosed that the %IE values of inhibitor A were somewhat lesser than those of inhibitor B under analogous circumstances. The influence of temperature was investigated and revealed that the %IE values decreased with rising temperature. Also, thermodynamic parameters were evaluated and discussed herein. The kinetics and mechanisms of the copper corrosion and its inhibition by the tested compounds were investigated. Molecular modeling provided strong evidence for the preference of the molecules A and B for their adsorption on the copper surface, while DFT investigations underlined the importance of N heteroatom as a relevant local site for molecular adsorption.

Although many different human activities such as the oil and gas sector, mineral production, utilities, transportation, etc. depend on the utilization of steel and its alloys, they are highly susceptible to corrosion, especially in acidic media. Hence, processing entails substantial material expenditures due to metal losses. In this regard, the inhibitory characteristics of the synthetic heterocyclic derivative (3aR,7S,7aS)-4,5,6,7,8,8-hexachloro-1,3- dioxo-1,3,3a,4,7,7a-hexahydro-2H-4,7-methanoisoindol-2-yl)benzenesulfonamide (MBSI) was studied against corrosion of C-steel in 0.5 M H2SO4 at 25-55 ◦C. The structure of the synthesized molecule was confirmed by FTIR, 1 H-NMR, 13C-NMR, and MS. Weight-loss, potentiodynamic polarization, electrochemical impedance spectroscopy, electrochemical frequency modulation measurements as well as theoretical analyses were employed in this investigation. The results showed that the investigated MBSI compound functions as an efficient inhibitor with a physical adsorption nature on the surface of carbon steel. MBSI concentration causes the inhibition efficiency to rise, reaching a maximum of 94% for the steel alloy corrosion at 37 × 10− 6 M and 25◦C. The synthesized compound was suggested to act as a mixed-type inhibitor. SEM surface analysis showed the construction of a protective layer at the carbon steel surface. DFT-based quantum chemical indices provided more insight into the inhibitory mechanism. Molecular dynamics (MD) simulations were also applied to predict the conformational adsorption change of the inhibitor on the iron surface. In addition, thermodynamic and kinetic parameters were calculated. The experimental results are largely consistent with the theoretical results.

In this report, N-benzylhydrazinecarbothioamide (BHCTA) was investigated as an organic inhibitor for the corrosion of copper substrate in 3.5 wt.% sodium chloride electrolyte at 298 K. The inhibition efficiency of BHCTA was examined using electrochemical, chemical and theoretical tools. The gained outcomes indicated a supreme inhibition efficiency of BHCTA which exceeded 95 % upon addition of 1.00 mM of BHCTA. Such supreme efficiency was discussed on the basis of decisive adsorption of BHCTA molecules on the copper substrate that hinders concurrently the anodic oxidation and cathodic reduction reactions progressions. The adsorption of BHCTA on the copper surface was discovered to obey Langmuir isotherm. The resulting value of Gads0 = −35.7 kJ mol−1 indicates that BHCTA molecules adsorb on the copper surface through a spontaneous mix of physisorption and chemisorption processes. A scanning electron microscope was used to examine the effect of BHCTA adsorption on the morphology of the copper surface. Theoretical calculations showed that BHCTA has good adsorption properties on Cu substrate. There is a good consistency between the applied experimental and theoretical tools, confirming the validity of the gained outcomes.

The use of corrosion inhibitors is considered as the supreme dominant approach to control the damage of metallic corrosion. Organic dyes are extensively employed as inhibitors for the corrosion of various metals and alloys in diverse media. Herewith, Alcian blue dye (ABD) was selected to investigate its inhibitive characteristics against the corrosion of copper in 1.0 M H2SO4 solution at 298 K. This investigation was monitored by various chemical, electrochemical, and spectroscopic techniques. The results indicated that the examined dye is a proficient inhibitor for the corrosion of copper in 1.0 M H2SO4 solution and its inhibition efficiency (% IE) was increased with augmenting its concentration and diminished with rising medium temperature. The high anticorrosive ability of the selected dye was attributed to its adherent adsorption of such dye on the Cu surface and follows Langmuir isotherm. Thermodynamics and kinetics of corrosion of copper and its inhibition by the examined dye were inspected. The mechanisms of copper corrosion in H2SO4 solution and its inhibition by ABD were proposed. The obtained results illuminated that the examined dye acts as a mixed-type inhibitor with cathodic precedence. Finally, all gained results with respect to % IE values of the dye were compared and designated a good harmony between all applied techniques.

In this paper, the degradation of fluconazole drug (Flz) was explored kinetically utilizing permanganate ion [MnO4 −] as an oxidant in different acidic environments, namely sulfuric and perchloric acids at various temperatures. Stoichiometry of the reactions between Flz and [MnO4 −] in both acidic environments was attained to be 1.2 ± 0.07 mol. The kinetics of the degradation reactions in both cases were the same, being unit order regarding [MnO4 −], fewer than unit orders in [Flz], and fractional second orders in acid concentrations. The rate of oxidative degradation of fluconazole in H2SO4 was higher than that in HClO4 at the same investigational circumstances. The addition of small amounts of Mg2+ and Zn2+ enhanced the degradation rates. The activation quantities were evaluated and debated. The gained oxidation products were characterized using spot tests. A mechanistic approach for the fluconazole degradation was suggested. Finally, the rate law expressions were derived which were agreed with the acquired outcomes. The rates of degradation for various [Flz] were mathematically modeled using the response surface methodology (RSM). The RSM model’s conclusions and the experimental findings are in agreement. The oxidative degradation mechanism of Flz using density functional theory (DFT) was performed. The fluconazole drug degrades in acidic settings, protecting both the environment and human health, according to a method that is easy to use, powerful, inexpensive, practical, affordable, and safe.

Due to the unique properties of steel, including its hardness, durability, and superconductivity, which make it an essential material in many industries, it lacks corrosion resistance. Herewith, two novel triazole-thione Schiff bases, namely, (E)-5- methyl-4-((thiophen-2-ylmethylene)amino)-2,4-dihydro-3H-1,2,4-triazole-3-thione (TMAT) and (E)-4-(((5-(dimethylamino)thiophen-2-yl)methylene)amino)-5-methyl2,4-dihydro-3H-1,2,4-triazole-3-thione (DMTMAT), were synthesized and characterized. The corrosion inhibition (CI) ability of these two molecules on carbon steel in an aqueous solution of 1 M HCl as well as their interaction with its surface was studied using a number of different techniques. The results confirmed that the CI capability of these organic molecules depends on their strong adsorption on the metal surface and the formation of a protective anticorrosion film. Weight loss tests revealed that the inhibition efficiencies of TMAT and DMTMAT were 91.1 and 94.0%, respectively, at 1 × 10−3 M concentrations. The results of electrochemical impedance spectroscopy (EIS) indicated that there was a direct relationship between the inhibitor concentration and the transfer resistance. Potentiodynamic polarization (PDP) experiments have proven to be mixed-type inhibitors of C-steel in aqueous hydrochloric acid solution and follow the Langmuir adsorption isotherm model. Several thermodynamic and kinetic parameters were calculated. The negative values of the adsorption-free energy are −36.7 and −38.5 kJ/mol for TMAT and DMTMAT, respectively, confirming the spontaneity of the adsorption process. The MD simulation study’s findings show that the inhibitor molecules are nearly parallel to the metal surface. The interaction energy calculated by the MD simulation and the inhibitory trend are the same. The practical implementation is consistent with what the computer models predicted.

Kinetics of isosorbide (S) oxidation by Ce(IV) in aqueous HClO4 medium has been examined via spectrophotometric technique at fixed ionic strength and temperature. The reaction showed a 1: 2 stoichiometry (S: Ce(IV)). The reaction was studied under pseudo-first order conditions. The dependency of the rate of oxidation reaction on the reactants’ concentrations showed that the reaction was first order in [Ce(IV)], whereas in both [H+] and [S], its order was lower than unity. The oxidation rate was directly proportional to ionic strength as well as dielectric constant of the reaction medium. However, it should be mentioned that adding Ce(III) had remarkably not affect the rate. The isosorbide oxidation product was recognized as (1S,4S,5R)-4-hydroxy-2,6-dioxabicyclo[3.3.0]octan-8-one). A mechanistic scheme for oxidation coherent with the observed kinetics was proposed. The rate-law expression was derived which was agreed with the acquired outcomes. The calculated activation quantities recommended construction of a rigid intermediate through the reaction and such process was endothermic and non-spontaneous.