Ayman H. Ahmed

Synthesizing New Hydrazone Derivatives and Studying their Effects on the Inhibition of Copper Corrosion in Sodium Chloride Solutions

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.

Nickel(II)-oxaloyldihydrazone complexes: Characterization, indirect band gap energy and antimicrobial evaluation

Abstract 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.

Physicochemical Studies and Heterogeneous Hydroxylation of Benzene on FeII, FeIII-Semicarbazone/Zeolite-Y Clathrates

Complexes of Fe(II) and Fe(III) with semicarbazone (SALSC) derived from salicylaldehyde and semicarbazide hydrochloride have been trapped in zeolite-Y super cages using “ship-in-a-bottle technique.” The synthesized new clathrates have been structurally characterized by various physicochemical techniques, in addition to surface area and nitrogen adsorption studies. The Fe(II) and Fe(III) ions inside zeolite-Y are coordinated with SALSC ligand via the (C=N), phenolic (OH), and deprotonated enolized (C=O) groups forming mononuclear structures. The results pointed out that the lattice oxygen zeolite was involved in coordination and the intrazeolitic ferrous and ferric semicarbazone complexes have prevailing octahedral configurations with noticeable high thermal stability. The catalytic activity of the new hybrid materials was checked for hydroxylation of benzene at 80°C using H2O2 as oxidant to give phenol.

Physicochemical studies on some selected oxaloyldihydrazones and their novel palladium(II) complexes along with using oxaloyldihydrazones as corrosion resistants

ABSTRACT New palladium (II) oxaloyldihydrazone complexes are reported and characterized. The mode of bonding as well as the structure of the isolated compounds have been ascertained on the basis of data obtained from elemental analyses (CHNM), spectral (UV-Vis., IR, mass and 1H NMR) and thermal (TG and DTA) measurements. Some optical parameters such as indirect optical band gap and refractive index were estimated for the isolated compounds. The inhibitive properties of all synthesized hydrazones toward the corrosion of carbon-steel in 1 M HCl solutions were tested. The adsorption of hydrazone inhibitors on steel surface proceeded as a spontaneous first order reaction.