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Cu(II) complexes with some hydroxy azo compounds derived from thiazole and benzothiazole have been synthesized. The structures of the complexes are inferred from data of elemental analysis, electronic, IR and H¹ NMR spectra. It is found that the Cu(II) coordinated to ligands through the nitrogen atom of azo group and hetero ring. This coordination lead to lower the energy of CT transition of ligands. The effect of molecular structure of the ligands and nature of the metal ion on complex formation are also examined. The free energy and stability constant of complexes formed in solution have been determined spectrophotometrically. Thiazole azo dyes were found to behave as an inhibitor with respect to the corrosion of copper in acidic solutions.

This paper aims to evaluate the inhibitive effect and adsorption behavior of 5-(ethylthio)-1H-tetrazole (EHT) and 5-(benzylthio)-1H-tetrazole (BHT) on copper in a sulfur-ethanol system.

Evaluation was carried out using electrochemical measurement and surface analysis techniques. Measurements of static friction coefficient by scanning electron microscopy and contact angle analysis were applied and finally confirmed the existence of the adsorbed film. The inhibitive mechanism of the two compounds was evaluated by means of quantitative calculation and molecular dynamics simulation. The friction coefficient of corrosion surface before and after adding corrosion inhibitor was determined through static friction coefficient measurements.

The electrochemical measurement indicated that the most effective concentration of two corrosion inhibitors was 70 mg L^–1, while the inhibition efficiency of that was EHT > BHT. The friction coefficient data showed that the addition of corrosion inhibitor reduced the roughness of the corrosion surface. Adsorption behavior of two inhibitors followed the Langmuir’s adsorption isotherm and was attributed to mixed-type adsorption. The results of quantitative calculation and molecular dynamics simulation showed that tetrazole rings of the two inhibitors and its connected S atoms were adsorbed on Cu(111) surface in parallel.

The corrosion inhibition performance of two tetrazolium derivatives in a sulfur-ethanol system was studied by combining experiments with theory, which provided a theoretical basis for the future research.