Experimental and theoretical studies of (Z)-N-(2-chlorobenzylidene) naphthalen-1-amine and (Z)-N-(3-nitrobenzylidene)naphthalen-1-amine, and their corrosion inhibition properties

Two Schiff base compounds, (Z)-N-(2-chlorobenzylidene) naphthalen-1-amine (CBN) and (Z)-N-(3-nitrobenzylidene)naphthalen-1-amine (NBN) were synthesized by the reaction between 1-naphthylamine and 2-chlorobenzaldehyde or 3-nitrobenzaldehyde respectively. The compounds were characterized using elemental analyses, NMR (1H and 13C), Fourier transform infra-red (FTIR) and mass spectroscopic techniques. From the 1HNMR, the azomethine hydrogen (CHN) gave a singlet at 8.95 ppm for CBN and 8.90 ppm for NBN. The molecular ion peaks from the mass spectra results are 266.07 and 277.09 g/mol for CBN and NBN respectively. The structures of the compounds were further verified using density functional theory (DFT) which showed the role of the electrons towards corrosion inhibition. The results of the electrochemical techniques using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) revealed that the two compounds are very good corrosion inhibitors with CBN showing better properties.