Evaluation of the Catalytic Activities of Some Synthesized Divalent and Trivalent Metal Complexes and Their Inhibition Efficiencies for the Corrosion of Mild Steel in Sulfuric Acid Medium

Metal Chelates of Sulfafurazole Azo Dye Derivative: Synthesis, Structure Affirmation, Antimicrobial, Antitumor, DNA Binding, and Molecular Docking Simulation

A series of divalent and one trivalent metal chelates of the azo ligand resulting from coupling of sulfafurazole diazonium chloride with resorcinol have been designed and synthesized. Structure investigation of the isolated chelates have been achieved by applying spectroscopic and analytical tools which collaborated to assure the formation of the metal chelates in the molar ratios of 1L: 1M for Ni(II), Co(II), and Fe(III) chelates, where Cu(II) and Zn(II) complexes formed in the ratio 2L : 1M. The geometrical arrangement around the metal canters was concluded from UV-Vis spectra to be octahedral for all metal chelates. The attachment of the ligand to the metal ions took place through the azo group nitrogen and o-hydroxyl oxygen through proton displacement leading to the ligand being in monobasic bidentate binding mode. Antimicrobial and antitumor activities of the interested compounds have been evaluated against alternative microorganisms and cancer cells, respectively, in a trial to investigate their extent of activity in addition to docking studies. The mode of interaction of the compounds with SS-DNA has been examined by UV-Vis spectra and viscosity studies.

Evaluation of synthesized biosurfactants as promising corrosion inhibitors and alternative antibacterial and antidermatophytes agents

This study investigated different amino acid-based surfactants (AASs), also known as biosurfactants, including sodium N-dodecyl asparagine (AS), sodium N-dodecyl tryptophan (TS), and sodium N-dodecyl histidine (HS) for their potential anticorrosion, antibacterial, and antidermatophyte properties. The chemical and electrochemical techniques were employed to examine the copper corrosion inhibition efficacy in H₂SO₄ (1.0 M) solution at 298 K. The results indicated their promising corrosion inhibition efficiencies (% IEs), which varied with the biosurfactant structures and concentrations, and the concentrations of corrosive medium. Higher % IEs values were attributed to the surfactant adsorption on the copper surface and the production of a protective film. The adsorption was in agreement with Langmuir adsorption isotherm. The kinetics and mechanisms of copper corrosion and its inhibition by the examined AASs were illuminated. The surfactants behaved as mixed-kind inhibitors with minor anodic priority. The values of % IEs gained from weight loss technique at a 500 ppm of the tested surfactants were set to be 81, 83 and 88 for AS, HS and TS, respectively. The values of % IEs acquired from all the applied techniques were almost consistent which were increased in the order: TS > HS ≥ AS, establishing the validity of this study. These surfactants also exhibited strong broad-spectrum activities against pathogenic Gram-negative and Gram-positive bacteria and dermatophytes. HS exhibited the highest antimicrobial activity followed by TS, and AS. The sensitivity of pathogenic bacteria varied against tested AASs. Shigella dysenteriae and Trichophyton mantigrophytes were found to be the most sensitive pathogens. HS exhibited the highest antibacterial activity against Shigella dysenteriae, Bacillus cereus, E. coli, K. pneumoniae, and S. aureus through the formation of clear zones of 70, 50, 40, 39, and 35 mm diameters, respectively. AASs also exhibited strong antifungal activity against all the tested dermatophyte molds and fungi. HS caused the inhibition zones of 62, 57, 56, 48, and 36 mm diameters against Trichophyton mantigrophytes, Trichophyton rubrum, Candida albicans, Trichosporon cataneum, and Cryptococcus neoformans, respectively. AASs minimal lethal concentrations ranged between 16 to 128 µg/ml. HS presented the lowest value (16 µg/ml) against tested pathogens followed by TS (64 µg/ml), and AS (128 µg/ml). Therefore, AASs, especially HS, could serve as an effective alternative antimicrobial agent against food-borne pathogenic bacteria and skin infections-associated dermatophyte fungi.

Experimental and Computational Exploration of Chitin, Pectin, and Amylopectin Polymers as Efficient Eco-Friendly Corrosion Inhibitors for Mild Steel in an Acidic Environment: Kinetic, Thermodynamic, and Mechanistic Aspects

Herein, the inhibition impacts of chitin, pectin, and amylopectin as carbohydrate polymers on the corrosion of mild steel in 0.5 M HCl were researched utilizing various experimental and theoretical tools. The acquired outcomes showed that the inhibition efficiencies (% IEs) of the tested carbohydrate polymers were increased by raising their concentrations and these biopolymers acting as mixed-kind inhibitors with major anodic ones. The acquired % IEs values were reduced with rising temperature. The higher % IEs of the tested polymers were inferred via powerful adsorption of the polymeric molecules on the steel surface and such adsorption obeyed the Langmuir isotherm. The computed thermodynamic and kinetic quantities confirmed the mechanism of physical adsorption. The kinetics and mechanisms of corrosion and its protection by polymeric compounds were illuminated. The results obtained from all the techniques used confirmed that there was good agreement with each other, and that the % of IEs followed the sequence: chitin > amylopectin > pectin.