Novel azo-benzoyl acetone metal complexes for inhibition of atmospheric steel corrosion.

The atmospheric corrosion threatens the structural reliability and service life of a wide range of engineering systems, which can cause economically significant degradation phenomena affecting metallic materials in industrial environments. Therefore, a New 2-((1H-indazol-5-yl) diazenyl)-1-phenylbutane-1,3-dione ligand (L) and its divalent cobalt, nickel, and copper complexes were synthesized and characterized. By using Elemental Analysis (CHN), Inductively Coupled Plasma (ICP), Molar Conductance (Λm), X-ray Powder Diffraction (XRD), Thermogravimetric analysis (TGA), and magnetic moment measurements. Also, Fourier Transform Infrared (FT-IR), Proton Nuclear Magnetic Resonance (1H-NMR), Carbon Nuclear Magnetic Resonance (13C-NMR), mass, and Ultraviolet-Visible (UV-Vis) spectroscopy. Through the nitrogen atom of the azo group and one oxygen atom of the carbonyl group, the ligand performs the function of a bidentate ligand. From the characterization and theoretical results, it was found that Co(II) and Ni(II) have an octahedral geometry, whereas the Cu(II) complex has a tetrahedral structure. The activity of ligand and its metal complexes as inhibitors to reduce the rate or prevent atmospheric corrosion of iron was investigated. Materials Studio 2017 software was used to study the adsorption on the Fe(110) surface. The computed adsorption energies follow the trend Cu(II) complex > Ni(II) complex > L > Co(II) complex, which is qualitatively consistent with the experimentally observed inhibition efficiency order. Scanning Electron Microscope (SEM) analysis proved that the specimen covered with Cu(II) complex has a good inhibitory effect that slows down the rate of corrosion compared with the blank and untreated specimen.