Synthesis, photophysical, voltammetric, and DFT studies of 4-aminochalones

Abstract

Aminochalcones, with a D-A-D architecture, were synthesized using Claisen-Schmidt condensation. The compounds were characterized by FTIR, melting point, HRMS, 1H, and 13C NMR spectroscopy and analyzed for UV–visible and fluorescence in different solvents (chloroform, acetonitrile, and methanol). All compounds showed absorption in the range of 330–420 nm and emission in the range of 400–550 nm. Both absorption and emission spectra exhibit bathochromic shifts from non-polar to polar solvents due to intramolecular charge transfer (ICT) interaction. Compounds 17 and 18 displayed mega Stokes shift (Δλ = 116–130 nm) in polar solvents giving these compounds a higher fluorescent character. Furthermore, HOMO-LUMO energy levels of compounds 17 and 18, evaluated through cyclic voltammetry, were found to be −5.10, −5.15, and −2.56, −2.99 respectively with band gap energy values 2.54–2.61 eV. The DFT and TD-DFT computations at the B3LYP functional along with a 6-31G(d,p) basis set for a comprehensive study of spectral data, molecular orbitals (HOMO, LUMO) analysis, and electrostatic potential (MEP) surfaces are also presented. The Computational studies support the experimental findings. The findings hint towards the optoelectronic efficiency of 17 and 18, and their potential for further optimization and use in optoelectronic devices.