Synthesis, density functional theory study, molecular dynamics simulation and anti-corrosion performance of two benzidine Schiff bases

Abstract

In this study, two Schiff bases named (E,E)-N,N’-biphenyl-4–4′diylbis[1-(thiophen-3-yl)methanimine] (BT) and 3-[(Z)-N(4′-aminobiphenyl-4yl)ethanimidoyl]-2-hydroy-6-methyl-4H-pyran-4-one (BD) have been synthesized and characterized using spectroscopic techniques. The XRD technique was employed to study the atomic packing, crystal structure and space group of the developed crystals of BD. The corrosion inhibition performance of BT and BD was investigated for mild steel corrosion in 1 M HCl medium using weight loss method and electrochemical techniques. Density functional theory (DFT) and molecular dynamics (MD) simulations were further applied to explain the adsorption as well as inhibition abilities of the molecules on the mild steel surface. Compounds revealed a good inhibition action in tested medium even at low concentrations and the inhibition efficiency increases with increasing concentration of inhibitors, and revealing a mixed-type inhibitor of predominantly anodic type. SEM and EDX studies revealed the film-forming ability of the molecules on the mild steel surface. DFT and MD studies complement experimental results and demonstrate that Schiff base moieties and functional groups are responsible for corrosion inhibitive performances of studied compounds.