8-Aminoquinoline derived two Schiff base platforms: Synthesis, characterization, DFT insights, corrosion inhibitor, molecular docking, and pH-dependent antibacterial study

Abstract

The current research divulges the synthesis of two new Schiff base (SB) (LNAPH/LO-VAN) derived from 8-aminoquinoline (8-AMQ) in the presence of 2-hydroxy naphthaldehyde (NAPH) and ortho-vanillin (O-VAN) in CH3OH solvent. They are structurally characterized by spectroscopic methods (IR/Raman/UV–vis/DRS/NMR) and SEM-EDX. SB compounds have a biologically active avenue of azomethine/imine group (H–C=N) that can donate N e's to Mn + ions, showing coordinating flexibility. The –OH and imine (H–C=N) groups are stable in air, light, and alkalis but undergo acidic environments hydrolysis, separating –NH2 and carbonyl compounds. Moreover, buffer solutions with a pH range of 4–6 release aldehyde. Molecular electrostatic potential (MEP), Frontier molecular orbitals (FMO), Fukui function, and Non-linear optical (NLO) were conducted to elucidate SBs chemical potency, optoelectronic significance, and corrosion inhibitor. Accordingly, the calculated ΔE of FMO for LNAPH and LO-VAN is 3.82 and 4.08 eV, ensuring potent biological function. DFT supported the experimental and theoretical IR spectral correlation to enrich better structural insights. NLO-based polarizability (α) and hyperpolarizability (β) factors successfully explore the potential optoelectronic significance. Molecular docking experiments were simulated against DNA, anti-COVID-19, and E. coli. The potential microbiological activity was screened against the bacterial strains E. coli, Klebsiella, Bacillus, and Pseudomonas sp. based on zone of inhibition and MIC values. These experiments also explored the fact that LNAPH and LO-VAN discourage microbial cell biofilms and corrosion. We extensively covered the as-prepared compounds' pH-dependent bacterial effects.

Keywords

• Schiff base
• DFT
• Corrosion inhibitor
• molecular docking
• pH-dependent antibacterial