Exploring Flavone Reactivity: A Quantum Mechanical Study and TDDFT Benchmark on UV-Vis Spectroscopy

Flavones exhibit a range of pharmacological and diverse biological activities, making them valuable candidates for drug development and complementary medicine. In this study, inclusive investigations of the chemical reactivity, kinetic stability, and biological activity of the flavone molecule are performed using B3LYP/6-311++G(d, p) density functional theory (DFT). The proton affinity (PA), ionisation energy (IE), and electron affinity (EA) along with global reactivity parameters such as chemical potential (µ), chemical hardness (η), softness (σ), electrophilic index (ω), and electronegativity (χ) of flavone molecule are computed. A comparative study with different DFT/correlation functional such as wB97XD, M062X, and MP2 shows that the adopted DFT method is reliable and computationally economical. Benchmark calculations using B3LYP, CAM- B3LYP, PBE0, M06-2X, LC-wHPBE, and wB97XD on the excited electronic states and absorption spectra indicate that CAM-B3LYP, M06-2X, and wB97XD are the most effective for predicting the absorption spectra of Flavone.