Experimental and theoretical insights on the photophysical properties of ester-substituted indolizines

Abstract

In this report, we present our latest results on the photophysical properties of substituted indolizines, which were previously obtained through the utilization of ultrasound (US) irradiation, in a one-pot and multicomponent strategy, allowing for a streamlined and straightforward preparation process. The photophysical properties of these derivatives were evaluated in solution using UV–Vis absorption and steady-state fluorescence emission spectroscopy. Our results reveal that these compounds exhibit absorption maxima in the UV-A-violet region. The electronic transitions could be related to spin and symmetry allowed ¹π→π* electronic transitions. The indolizines present fluorescence in the violet-to-green region. Both ground and excited states were shown to be tailored by the substituents in the indolizine core. In addition, the role of the solvent in the deactivation of the excited state proved to be critical in the successful exploration of these compounds as optical sensors for benzene. When benzene was added to the ethanolic solution, the indolizines usually exhibited fluorescence quenching, with a linear relationship between the amount of benzene and the emission intensity. Theoretical calculations were also employed to gain a deeper understanding of the solute-solvent interactions.