Experimental and theoretical studies of azomethines derived from benzylamine as corrosion inhibitors of mild steel in 1 M HCl

•Organic inhibitors offer good protection of the metal from corrosion.•Azomethine used as organic inhibitor due to the presence of nitrogen (N) atom in CN.•The azomethines adsorbed on the metal surface and act as a barrier between metal and electrolyte interface.•XPS analysis confirm the elemental compositions and its chemical state that corresponds to the type of adsorption for azomethine.•DFT reveals the electronic structure of the whole molecule which promotes high inhibition efficiency.