Electronic, Structural and Optical Studies of (1,3‐Diphenyl‐1 H ‐azole‐4‐yl)methylene Derivatives: A DFT and Experimental Approach

ABSTRACT The pyrazole‐based derivatives containing hydantoin and barbiturate moieties were synthesized and characterized using 1 H‐NMR, 1 3 C‐NMR, high‐resolution mass spectrometry (HRMS), Infrared Spectroscopy (IR), and UV–visible spectroscopy for structural studies and to evaluate their potential for optoelectronic applications. Quantum computations were performed with B3LYP, B3LYP‐D3, and CAM‐B3LYP functionals with the 6–311G(d,p) basis set. The TD‐B3LYP and TD‐CAM‐B3LYP methods with the 6–311G(d,p) basis set were employed to predict the UV–vis absorption spectra and oscillator strengths in the ethanol solvent phase. The Mulliken atomic charge distribution was employed to visualize electron‐rich and electron‐deficient regions. The energy gap between the HOMO and LUMO levels was evaluated to calculate the reactivity descriptors such as chemical potential (μ), electronegativity ( χ ), hardness ( η ), softness ( S ), electrophilicity index ( ω ), and maximum additional electronic charge (∆ N max ), providing a comprehensive understanding of the electronic behavior and chemical stability of the compounds. The key optical properties such as the refractive index, optical band gap, dielectric constant, and extinction coefficient were analyzed. With band gaps of 2.84 eV (pyrazole‐barbiturate hybrid) and 3.27 eV (pyrazole‐hydantoin hybrid), these compounds fall in the wide‐bandgap semiconductor range.