O-methoxybenzaldehydebenzoylhydrazone (O-MBH) and bis-(o-methoxybenzaldehyde)-thiocarbodihydrazone (O-MTH) were synthesized. The O-MBH and O-MTH effects on the inhibition of copper corrosion in 3.5% NaCl solution were investigated. Electrochemical measurements showed that the addition of O-MBH and O-MTH decreased the corrosion parameters of copper in the test solutions. The weight loss experiments indicated that O-MBH and O-MTH decreased the corrosion rate of copper. The data pointed out that O-MBH and O-MTH inhibit the copper corrosion in NaCl solution with inhibition efficiency in the order of O-MTH > O-MBH.

Corrosion of iron in sodium chloride (3.5% wt) solutions and its inhibition by ethanedihydrazide (EH) have been reported. Electrochemical impedance spectroscopy (EIS), cyclic potentiodynamic polarization (CPP), and change of current with time at −475 mV (Ag/AgCl) measurements were employed in this study. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) techniques were utilized to report surface morphology and elemental analysis, respectively. The presence of 5 × 10^–5 M EH was found to inhibit the corrosion of iron, and the effect of inhibition profoundly increased with an increase in EH concentration up to 1 × 10^–4 M and further to 5 × 10^–4 M. The low values of corrosion current and high corrosion resistance, which were obtained from the EIS, CPP, and change of current with time experiments, affirmed the adequacy of EH as a corrosion inhibitor for iron. Surface investigations demonstrated that the chloride solution without EH molecules causes severe corrosion, while the coexistence of EH within the chloride solution greatly minimizes the acuteness of chloride, particularly pitting corrosion.

A series of oxaloyldihydrazone ligands were prepared essentially by the conventional condensation reaction between oxaloyldihydrazide and different aldehydes e.g., salicylaldehyde, 2-hydroxy-1-naphthaldehyde, 2-hydroxyacetophenone and 2-methoxybenzaldehyde in 1:2M ratio. The synthesized compounds were purified to give bis(salicylaldehyde)oxaloyldihydrazone (L1), bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (L2), bis(2-hydroxyacetophenone)oxaloyldihydrazone (L3) and bis(2-methoxybenzaldehyde)oxaloyldihydrazone (L4). All the oxaloyldihydrazones (L1–L4) and their relevant solid copper(II) complexes have been isolated and characterized by various physicochemical techniques. The identity of the synthesized compounds has been ascertained on the basis of elemental analyses, spectral (UV–Vis, IR, ESR, mass, 1H NMR), magnetism and thermal (TG) measurements. The dihydrazones coordinate to the metal center forming binuclear complexes. Upon chelation, the metal center can form a trigonal distorted octahedral structure with L1 and pseudo tetrahedral configuration with L2 & L3 & L4. The optical band gap energy for all compounds underlies the range of semiconductor materials. The investigated ligands were assayed for their corrosion inhibitive and adsorptive properties on copper surface in 1M HCl solution using weight loss technique. The results pointed out that, the ligands have a plausible inhibition toward the corrosion of copper specimen. The adsorption reaction on copper surface was found to be spontaneous first order and agreed with physical adsorption mechanism. The adsorption data fitted well to Freundlich, Langmuir and Frumkin adsorption isotherms

A series of oxaloyldihydrazone ligands was prepared essentially by the usual condensation reaction between oxaloyldihydrazide and different aldehydes e.g. salicylaldehyde, 2-hydroxy-1-naphthaldehyde, 2-hydroxyacetophenone and 2-methoxy-benzaldehyde in 1:2 M ratio. The formed compounds were purified to give bis(salicylaldehyde)oxaloyldihydrazone (L₁), bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (L₂), bis(2-hydroxyacetophenone)oxaloyldihydrazone(L₃) and bis(2-methoxy-benzaldehyde)oxaloyldihydrazone (L₄). All the oxaloyldihydrazones (L₁–L₄) and their relevant solid nickel(II) complexes have been prepared and structurally characterized on the basis of the elemental analyses, spectral (UV–vis, IR, mass and ¹H NMR), magnetism and thermal (TG) measurements. The dihydrazones coordinate to the metal center forming mononuclear complexes with L₁, L₃ and L₄ in addition to binuclear complex with L₂. The metal center prefers tetrahedral stereochemistry upon chelation. The optical indirect band gap energy for all compounds underlies the range of semiconductor materials. The prepared ligands and their metal complexes have been assayed for their antimicrobial activity against fungi as well as Gram-positive and Gram-negative bacteria. The resulting data indicate the ability of the investigated compounds to inhibit the growth of some micro-organisms, where L₂ showed the highest activity among all the compounds. Minimum inhibitory concentration (MIC) of L₂ against the growth of five micro-organisms was determined which gives better response against Aspergillus fumigatus and Bacillis subtilis compared with some selected standard drugs.