Schiff base ligand (H(3)L) was prepared from the condensation reaction of protochatechualdehyde (3,4-dihydroxybenzaldhyde)with 2-amino phenol. From the direct reaction of the ligand (H(3)L) with Co(II), Ni(II) and Cu(II) chlorides, and Fe(III)and Zn(II)nitrates in 2 M/1 L molar ratio, the five new neutral complexes were prepared. The characterization of the newly formed compounds was done by (1)H NMR, UV-Vis, and IR spectroscopy and elemental analysis. The in vitro antibacterial activity of the metal complexes was studied and compared with that of free ligand.

This work consists of a study of the corrosion‐inhibiting and semiconducting properties of new binuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes with a Schiff base, H2L, obtained from the 2:1 M condensation of salicylaldehyde and o‐dianisidine, respectively. Elemental, spectral and thermal analyses were used to characterize these complexes. The magnetic susceptibilities of these complexes were also determined. Weight loss, potentiodynamic polarization and scanning optical microscopy were the techniques used to investigate the efficiency of these new compounds as corrosion inhibitors. The antibacterial activity of the compounds was measured against sulfate‐reducing bacteria. It was found that inhibition occurs via the chemisorption of metal complexes on the steel surface. This absorption obeys the Langmuir adsorption isotherm model.