Corrosion Inhibition Activity of Transition Metal (II) Complexes of a Bidentate Ligand for Mild Steel in Acidic Medium Pertinent to Green Chemistry

A new bidentate amide ligand 2-(2-acetylaminophenyl)-N-benzothiazol-2-oxo-acetamide (apba) and its complexes with Co2+, Ni2+ and Cu2+ have been synthesized using microwave-assisted synthesis (MAS) under mild conditions with excellent yields (up to 85%) in shorter reaction times (in 5-10 min). All compounds have been characterized by spectro-analytical techniques. The corrosion inhibitory effects of the investigated ligand and its metal (II) complexes on mild steel were studied in 1.0 M HCl at different concentrations using the 'weight loss method' which revealed the high inhibition efficiency of the complexes compared to the free ligand. The data show that the inhibitory efficiency obtained by the investigated compounds increased as the concentration of the compounds increased and follow the order Co>Ni>Cu>ligand.