Exploring flavone reactivity: A quantum mechanical study and TD-DFT benchmark on UV-vis spectroscopy

Flavones are known for their broad spectrum of pharmacological and biological activities, making them promising candidates for drug development and complementary medicine. In this study, a comprehensive analysis of the chemical reactivity, kinetic stability, and biological potential of the flavone molecule is performed using density functional theory (DFT) at the D3-B3LYP/6-311++G(d,p) level. The key molecular properties-proton affinity (PA), ionization energy (IE) and electron affinity (EA)-are calculated alongside global reactivity descriptors such as chemical potential (μ), chemical hardness (η), softness (σ), electrophilic index (ω), and electronegativity (χ). To ensure the reliability and cost-effectiveness of the chosen DFT method, a comparative analysis is performed using various functionals, including D3-B3LYP, wB97XD, M06-2X and MP2. Furthermore, time-dependent DFT (TD-DFT) calculations are performed with multiple functionals B3LYP, CAM-B3LYP, PBE0, M06-2X, LC-wHPBE and wB97XD to investigate the excited-state properties and UV-visible absorption spectra of flavone. The results indicate that CAM-B3LYP, M06-2X, and wB97XD provide the most accurate predictions for the absorption characteristics of the flavone molecule.