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T WO triazole Schiff base derivatives N-(furan-2-ylmethylene)-1H-1,2,4-triazole-3-amine (FTA), N-(thiophene-2-ylmethylene)-1H-1,2,4-triazole-3-amine (TTA) and their metal complexes Co(II), Ni(II), Cu(II) and Zn(II) were synthesized under microwave irradiation. The structure of these compounds has been investigated by using elemental analysis, FT-IR, UV-Vis spectrometric methods, magnetic susceptibility, mass spectra, NMR, ESR and thermal studies. The antimicrobial activities of the prepared ligands and their respective Zn (II) complexes were studied against the bacterial (positive and negative) grams and fungal strains. The inhibitive characteristics of Schiff base ligands on C-steel corrosion in hydrochloric acid were studied using weight loss measurements. The prepared Schiff base derivatives show high inhibition efficiency and their adsorption surface was found to obey Langmuir model. The data also revealed that FTA is less than TTA in terms of inhibiting efficiency.

A Schiff base ligand of o -vanillin and 4-aminoazobenzene and its transition metal complexes of Ni(II), Co(II), Zn(II), Cu(II), Mn(II), and Zr(IV) were prepared under microwave irradiation as a green approach compared to the conventional method. The structures of new compounds have been characterized and elucidated via elemental and spectroscopic analyses. In addition, magnetic susceptibility, electron spin resonance, and electronic spectra of the synthesized complexes explained their geometrical structures. The thermal stability of Cu(II), Zn(II), and Zr(IV) complexes was studied by thermo-gravimetric analyses (TGA). Coats–Redfern and Horowitz–Metzger equations were used to calculate the thermal and dehydration decomposition activities of proposed structures kinetically. Surface morphologies of the solid compounds were imaged by scanning electron microscopy (SEM). The particle size of prepared complexes was measured by using a particle size analyzer at a diffraction angle of 10.9°. The geometry structures of the synthesized compounds were verified utilizing electronic spectra, ESR spectrum, and magnetic moment value. The newly synthesized compounds were screened for antimicrobial activity. Also, the anticancer activity of the free Schiff base ligand and its metal complexes were studied against two cell lines: human colon (HCT-116) and human liver cancer cells (HepG-2). The obtained results showed that the Cu(II) complex displayed the highest cytotoxic activity (IC 50 = 18 and 22 μg/mL for HepG-2 and HCT, respectively) compared to the free Schiff base ligand.

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The effect of chloride ion concentration and pH of solution on the corrosion behavior of aluminum alloy AA7075 coated with phenyltrimethoxysilane (PTMS) immersed in aqueous solutions of NaCl is reported. Potentiodynamic polarization, linear polarization, open circuit potential, and weight loss measurements were performed. The surface of samples was examined using SEM and optical microscopy. Elemental characterization of the coating by secondary ion mass spectrometry indicates an intermediate layer between coating and aluminum alloy surface. The corrosion behavior of the aluminum alloy AA7075 depends on chloride concentration and pH of solution. In acidic or neutral solutions, general and pitting corrosion occur simultaneously. On the contrary, exposure to alkaline solutions results in general corrosion only. Results further reveal that aluminum alloy AA7075 is susceptible to pitting corrosion in all chloride solutions with concentrations between 0.05 M and 2 M NaCl; an increase in the chloride concentration slightly shifted both the pitting and corrosion potentials to more active values. Linear polarization resistance measurements show a substantially improved corrosion resistance value in case of samples coated with PTMS as compared to uncoated samples in both neutral (pH=7), acidic (pH=0.85 and 3), and alkaline chloride solutions (pH=10 and 12.85). The higher corrosion resistance of the aluminum alloy coated with PTMS can be attributed to the hydrophobic coating which acts as a barrier and prevents chloride ion penetration and subsequent reaction with the aluminum alloy.