Functional Chalcones: Influence of Hydroxyl Substitution on Their Optical Properties

Chalcones, known for their versatile applications in organic synthesis, chemical sensing, therapeutics, optoelectronics, and non-linear optics, possess a distinctive triple-carbon chain linking two aryl rings. This study explores the optical and electronic characteristics of hydroxyl (–OH) functionalised simple chalcones. Here, we synthesised hydroxyl (–OH) substituted chalcones via a single-step Claisen-Schmidt condensation using selected aldehydes and ketones, achieving a yield of 89–93%. The resulting chalcones (3aa, 3ba, 3ab, and 3bb) were structurally characterised using advanced spectroscopic techniques, including FT-IR, 1H NMR, 13C NMR, and HRMS. We looked into the chalcones’ optical properties using UV–visible spectroscopy in chloroform. The results showed activity in the ultraviolet (UV) region and multiple absorption bands in the longer UV range because of hydroxyl substitution. Photoluminescence (PL) studies further demonstrated the influence of hydroxyl substitution on electronic and optical properties, highlighting their potential for emission purposes. Gaussian 09W software performed theoretical studies to validate the experimental findings. The optimised molecular structures were visualised using Gauss View 5.0. Density functional theory (DFT) calculations, employing the B3LYP functional with a 6–31+g(d) basis set, provided insights into the structural features and electronic properties through Frontier Molecular Orbital (FMO) analysis. This comprehensive study underscores the significant role of hydroxyl substitution in tuning the electronic and optical properties of chalcones, offering valuable perspectives for their optical application.