Corrosion Inhibition and Antimicrobial Studies of Imine Chelator and its M(II) Chelates: Synthesis and Characterizations

Background and Objective: Organic molecules with non-carbon atoms, have found applications in many fields of life science and technology. They constitute the vast majority of the molecules involved in the operations of man in exerting control over nature. Thus, studies of some bivalent metal chelates of bidentate imine-chelator (LH) acquired from 2-hydroxyl-1-naphthaldehyde (2-HNA) and 2-amino-6-ethoxybenzothiazole (2-AEBT). Materials and Methods: The synthesis, characterization and corrosion inhibition studies were carried out via facile reactions, analytical spectral, theoretical and inhibitive methods reported in our previous works. The antimicrobial properties of the synthesized compounds were tested in vitro against P. mirabilis, E. coli, S. aureus, K. oxytoca, S. Epidermidis, S. Pneumoniea, A. niger, A. flavus and Fuserium sp., strains. Results: The vibrational spectra of LH revealed a band at 1622 cm‾¹, which was ascribed to the -C=N- stretching vibration which appeared at lower frequencies in the chelates’ spectra indicating chelation. Jobs’ method of continuous variation suggests 1:2 metal to ligand ratio. The effect of LH and its chelates on acid deterioration of mild steel (ms) was visible indicating that LH had considerable corrosion inhibition (CI) performance in contrast to corrosion of ms in a 1M HCl solution. The premeditated zinc complex had the best antibacterial activity while the manganese complex showed enormously fine antifungal actions against the screened microbes with inhibitory zones of 15.0 and 26.5 mm separately. Conclusion: The synthesized compounds had the highest antibacterial and antifungal actions against Streptococcus sp., A. niger. The absorption of the compounds on the metal surface was proven by the Density Functional Theory (DFT) calculations showing they are potential corrosion inhibitors for steel protection.