Abstract
The inhibitive action of azo dye aminophenol derivatives, namely 6-(4-benzenesulfonic acid azo)-3-aminophenol (compound (1)) and 4-(2,3-dimethyl-1-phenylpyrazol-5-one azo)-3-aminophenol (compound (2)) against the corrosion of C-steel in 2 M HCl solution using Tafel polarisation, surface morphology, electrochemical impedance spectroscopy and electrochemical frequency modulation techniques. The inhibition efficiency increased with increasing inhibitor concentrations and decreased with increasing temperature. Tafel polarization curves showed that the corrosion rate was decreased with increasing compounds concentration into HCl solution. Inhibition efficiency values obtained from various methods employed were in reasonable agreement. It was found that the order of percentage IE of these investigated compounds obey the following order: compound (2) > compound (1). In addition, the antimicrobial and antifungal activities of the aminophenol derivatives compounds (1 and 2) and comparing them with the standard antibacterial and antifungal drugs were described. The results showed that the compound (2) is very good antibacterial agents against Bacillus subtilis and Staphylococcus aureus. The compound (2) is more active than the compound (1) and penicillin G against Bacillus subtilis and Staphylococcus aureus. It was found that the compound (2) is more active than penicillin G which is used as the antibacterial standard drug against Enterobacter sp. and Klebsiella pneumoniae. Molecular docking was used to predict the binding between aminophenol derivatives compounds (1 and 2) and the receptors of the crystal structure of Staphylococcus aureus (3q8u) and the crystal structure of Escherichia coli (3t88). The compound (2) showed best interaction with receptor of Staphylococcus aureus (3q8u) than the compound (1).