Synthesis, DFT and photophysical studies of a new thiophene-fused naphthalene chalcone

In the present study, we describe the synthesis of a new thiophene-substituted chalcone, namely (E)-3-(5-methylthiophen-2-yl)-1-(6-methoxynaphthalen-2-yl)prop-2-en-1-one (P1), through a well-known base-catalysed aldol condensation reaction. The molecular structure of P1 was analysed using a spectroscopic technique, including FTIR, ¹H and ¹³C nuclear magnetic resonance, and mass spectrometry. Further examination of the optical characteristics was conducted using ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopy. UV–Vis spectra of P1, studied using a different solvent, displayed two sets of absorption bands near 290–310 nm and 360–400 nm, which were attributed to π–π* transition, indicating a bathochromic shift. PL measurements revealed a single emission peak centered at 475 nm in solution and a dual-emission profile in the solid state, with maxima at 510 and 610 nm. Furthermore, density functional theory (DFT) calculations at the B3LYP/TZVP level, along with time-dependent DFT (TD-B3LYP/TZVP) for excited-state and absorption studies, were employed to gain deeper insight into the molecular structure and electronic transitions.