Quantum Chemical and Spectroscopic Characterization of a Triazole Thiophene Derivative: Insights from DFT and TD-DFT Studies

This work delivers a rigorous density-functional investigation of 5-(1H-1,2,4-triazol-1-yl)-2-thiophenecarboxylic acid (TTCA). Hybrid-functional DFT calculations yield a near-planar, π-conjugated geometry and a HOMO–LUMO gap of ~ 3.1 eV, confirming the molecule’s electronic stability and photoactivity. Simulated FT-IR, NMR, and UV–Vis spectra reproduce key experimental fingerprints, with broad π→π* and n→π* absorptions underscoring optoelectronic promise. DOS and OPDOS profiles reveal efficient charge transfer across the triazole–thiophene scaffold, while electrostatic-potential mapping pinpoints electrophilic and nucleophilic sites relevant to metal coordination and molecular recognition. Reduced-density-gradient analysis visualizes weak intermolecular forces that may facilitate supramolecular assembly. These insights position TTCA as a versatile candidate for sensor platforms, coordination complexes, and bioactive materials, and they outline clear avenues for future optimization and application.