Novel Cu (II) and Zn (II) complexes of 8-hydroxyquinoline derivatives as effective corrosion inhibitors for mild steel in 1.0 M HCl solution: Computer modeling supported experimental studies

摘要

In this work, we have synthesized and characterized novel complexes of copper (II) and zinc (II). These complexes were obtained by reacting of 5-azidomethyl-8-hydroxyquinoline with copper chloride dihydrate and zinc chloride dihydrate. The isolated complexes were characterized by UV-visible spectroscopy (UV-Vis), Elemental analysis (FA), Infrared (IR), Mass spectrometry (MS) and H-1 and C-13 Nuclear Magnetic Resonance (NMR). These complexes were tested as corrosion inhibitors of mild steel in 1.0 M HCl by experimental and theoretical investigations. The surface of the steel before and after corrosion was characterized by the Scanning Electron Microscope coupled with Dispersive Energy Analysis (SEM-EDAX) and the gravimetric solution was analyzed by UV-visible spectrometry. The results of electrochemical and theoretical studies and the surface analysis of the steel show that these two complexes are effective for the protection of steel in 1.0 M HCl, but the high-temperature complexes become less effective, in addition, these complexes are adsorbed to the steel surface following the isotherm of Langmuir. (C) 2019 Elsevier B.V. All rights reserved.