Targeted synthesis of two iron(III) tetradentate dibasic chelating Schiff base complexes toward inhibition of acidic induced steel corrosion: Empirical and DFT insights

Abstract

Two new azomethine chelates for Fe 3+ ions were prepared from two dibasic tetradentate chelating imine ligands. The studied Schiff base ligands were 2,2 0 -((1E,1 0 E)-((4-nitro-1,2-phenylene)bis(azanylylidene))bis(methanylylidene))bis (4-bromophenol) (NABS) and 2,2 0 -((1E,1 0 E)-((4,5-dimethyl-1,2-phenylene)bis (azanylylidene))bis(methanylylidene))bis(4-bromophenol) (MABS). Alternative spectral and physicochemical tools such as Fourier transform infrared spectroscopy (FTIR), C 13 NMR, 1 H NMR, and CHN analyses, thermogravimetric analysis (TGA), molecular electronic spectra, and magnetic susceptibility measurements were applied to inspect the structural composition of the compounds under investigation. In addition, the DFT approach was used to optimize the geometry of all compounds in order to get ideal structures and important characteristics. The synthesized compounds examined as an anticorrosive films of C-steel in acidic chloride medium utilizing theoretical and electrochemical studies such electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and potentiodynamic anodic polarization curve (PAP) approaches. The inhibition efficiency augmented with the increasing of the inhibitor dose. The prepared Schiff bases and their iron complexes exhibited protection capacity around 96.8% in the presence of 0.5 mmol L À1 . PDP outcomes approve the additive molecules act as mixed inhibitors. The Langmuir model is followed by Schiff bases and their iron complexes as it is contains both chemical and physical adsorption on the metal interface. The surface morphology of the substrate (in blank and inhibited systems) was scanned using field-emission scanning electron microscopy (FESEM). A good agreement among experimental techniques and corresponding density functional theory (DFT) results was found, which confirmed the purity of the studied compounds and suggested octahedral geometry around Fe(III) ions in both MABSFe and NABSFe complexes.

Innovation of Imine Metal Chelates as Corrosion Inhibitors at Different Media: A Collective Study

“…This explains that CS resistance to opposing aggressivity increased and the NABSFe is classified as opposing corrosion enhancers. As a good agreement between experimental methods and corresponding DFT, the observed data from DFT displayed which NABSFe chelates offer the best protective effects [ 102 ].…”

Structural, electronic and optical properties of synthesized schiff base compound-validation with a computational method

“…Induced changes in charge density enhance molecular interactions influencing reflectivity with transitions that influence Fermi energy at reduced optical frequencies. In summary the synthesized organic compounds contribute to higher energy minima, reduced energy gaps, reduced hardness (opposition), and higher electrophilicity index (more reactive) in compared to inorganic molecules with metal chelates derived from isatin [68] and Schiff base complexes [69].…”

Norfloxacin Skeleton-Included Dendritic Molecules as Corrosion Inhibitors on Mild Steel in Hydrochloric Acid: From Experiments to Molecular Dynamics Simulation

“…In addition, the strong chemical coordination bonds may be formed between the lone electron pairs of heteroatoms in the DMs and the empty orbitals of iron atoms, which greatly enhances the chemisorption. Meanwhile, the aromatic rings in the DMs can also provide free π electrons to further increase the chemisorption, 72 which may play a dominant role in the formation of the adsorption films of the DMs on mild steel surface. The schematic diagram of the adsorption of the studied molecules on mild steel surface is shown in Fig.…”