Synthesis and Characterization of Some Complexes Derived from Isatin Dye Ligand and Study of their Biological Potency and Anticorrosive Behavior on Aluminum Metal in Acidic Medium

Divalent Mn, Ni, Zn, and trivalent La complexes of H₃L ligand [N’,2-bis((Z)-2-oxoindolin-3-ylidene)hydrazine-1 carbohydrazide] were synthesized and characterized via diverse spectroscopic methods (FT-IR, NMR, electronic, PXRD, and GC-MS), molar conductance and magnetic susceptibility measurements. The different ways of binding for the H₃L ligand with metal ions were inferred, as the H₃L ligand acted in mono-negative N²O tridentate, mono-negative N²O³ pentadentate, bi-negative N²O³ pentadentate, and tri-negative N²O³ pentadentate manners in coordination to Mn²⁺, Zn²⁺, La³⁺, and Ni²⁺ metal ions, respectively. DFT modeling was performed using the DMOL³/material studio software, and some of the experimental outcomes were interpreted and authenticated. Electrochemical performance of Mn²⁺ ions in the existence and absence of H₃L ligand was considered via cyclic voltammetry. The corrosion effectiveness of the H₃L ligand (inhibitor) to aluminum metal was evaluated, and the molecular dynamic (MD) simulations for adsorption of the H₃L inhibitor on Al surface were performed via FORCITE quench code. The isolated compounds were inspected for their antimicrobial (against C. albicans fungi, G⁺ bacteria S. aureus and B. subtilis, and G^? bacteria P. aeruginosa and E. coli), cytotoxic, and antioxidant (ABTS, and SOD) activities. A molecular docking study was performed to give the favorable binding sites for the ligand to E. coli, and S. aureus proteins.