Design, spectroscopic characterization, DFT, molecular docking, and different applications: Anti-corrosion and antioxidant of novel metal complexes derived from ofloxacin-based Schiff base

Abstract

A new tridentate Schiff base ligand derived from ofloxacin (oflo) with 2-aminophenol was synthesized and a series of d-transition metal complexes were prepared. The ligand and its metal complexes were investigated using elemental, spectral, and thermal studies. The molecular and electronic structure of the free ligand and its Zn(II) complex were refined theoretically, and the chemical quantum parameters were computed. SEM studies were conducted on the free ligand and its Ni(II) chelate to confirm their nanostructure. The anti-corrosive performance of HL for mild steel (MS) was employed using electrochemical frequency modulation (EFM), potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS) and showed a significant efficiency as anticorrosion agent (89.71%). Molecular docking studies were carried out between the ligand and its [Zn(HL)(H2O)Cl2] complex with active sites of 3T88, 3Q8U, and 3Q7K receptors and the complex showed the strongest binding with 3T88 receptor (-31.9 kcal mol−1). The antioxidant activity of the free ligand and its metal chelates had been carried out using the standard DPPH method and the free ligand showed the highest antioxidant activity (IC50 = 10.52 µg/mL). The in vitro antibacterial activity showed that all prepared compounds were biologically active and Fe(III) complex has the highest inhibiting activity against Proteus Vulgaris Gram-negative bacteria.