Synthesis, characterization, and inhibition effects of a novel eugenol derivative bearing pyrrole functionalities on the corrosion of mild steel in a HCl acid solution.

Semi-synthetic modifications of natural products have yielded numerous anti-cancer drugs, antimicrobials, and corrosion inhibitors. In this study, eugenol, a natural product, was synthetically modified to generate a novel heterocyclic compound: pyrrole, which forms crystals. The latter is the outcome of the condensation reaction between eugenol hydrazide and 2,5-hexanedione, conducted under reflux ethanol conditions, without a catalyst, achieving a 96% yield. This compound structure was characterized through spectroscopic methods, such as NMR and FTIR, and validated par the crystal's X-ray diffraction analysis. According to the findings of the electrochemical study, pyrrole demonstrated effective inhibition against the carbon steel's corrosion in a 1 M HCl acid solution.

Crystal structure of (Z)-3-allyl-5-(3-bromo-benzyl-idene)-2-sulfanyl-idene-1,3-thia-zolidin-4-one.

In the title compound, C13H10BrNOS2, the rhodanine (systematic name: 2-sulfanyl-idene-1,3-thia-zolidin-4-one) and the 3-bromo-benzyl-idene ring systems are inclined slightly, forming a dihedral angle of 5.86 (12)°. The rhodanine moiety is linked to an allyl group at the N atom and to the 3-bromo-benzyl-idene ring system. The allyl group, C=C-C, is nearly perpendicular to the mean plane through the rhodanine ring, maling a dihedral angle of 87.2 (5)°. In the crystal, mol-ecules are linked by pairs of C-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(10) ring motif.

Corrosion resistance of NiTi in fluoride and acid environments.

The aim of our study was to assess in the laboratory the electrochemical behavior of nickel-titanium alloy (NiTi) by simulating the aggressive conditions found in the mouth (notably fluoride and acidity) in order to determine its biocompatibility. The impact of fluoride and pH acid on the corrosion resistance of orthodontic NiTi was studied using classic electrochemical measurement techniques including follow-up over time of the corrosion potential, polarization measurements and impedance spectroscopy. In addition, scanning electron microscopy was used to evaluate the status of the alloy surface before and after immersion in the different media. The results demonstrated the particularly low corrosion resistance of NiTi alloy in the presence of fluorides. In an acidic environment, the alloy showed greater resistance thanks to the passivation phenomenon. The synergistic action of fluoride and ph Acid on NiTi corrosion was not clearly demonstrated.