Theoretical investigation, spectroscopic characterization, global chemical reactivity, nonlinear optical properties, and antioxidant activity of 2-(2,4-dimethoxybenzylidene)-hydrazono-1,2-diphenyl-ethanone

This study investigates the molecular properties of 2-[(2,4-Dimethoxybenzylidene)-hydrazono-1,2-diphenyl-ethanone] (DBHDE) using experimental (IR, UV–Vis, NMR spectroscopy) and theoretical approaches using the DFT/B3LYP method and the 6–311G (d, p) basis set. Vibrational modes were assigned via potential energy distribution (PED), with computed and experimental FT-IR spectra showing good agreement. NMR calculations referenced tetramethylsilane (TMS). Frontier Molecular Orbital (FMO) analysis highlighted reactive sites, while the HOMO-LUMO gap quantified chemical reactivity. TD-DFT modeling of UV–Vis spectra revealed electronic transitions and charge transfer. Mulliken charges, chemical reactivity descriptors, and NBO analysis confirmed significant intramolecular charge transfer (ICT). The molecular electrostatic potential (MEP) map identified electrophilic and nucleophilic sites. Nonlinear optical (NLO) properties, including dipole moment, polarizability, and hyperpolarizabilities, were evaluated to link structure to optical behavior. Antioxidant activity, assessed using the DPPH assay, demonstrated moderate activity compared to standard references.