Impact of Azobenzene Side Chains on the Ultraviolet–Visible and Fluorescence Properties of Coumarin Derivatives
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide The effect of photoswitchable compounds on the light-emitting properties of nanoparticles has been drawing increasing attention. To investigate the effect of photoswitchable azobenzene units on the photophysical properties of coumarin, a biologically relevant fluorophore, photoresponsive azobenzene-coumarin derivatives were synthesized and characterized. The investigation of the effect of azobenzene isomerization on the ultraviolet (UV)–visible absorption and fluorescence properties of coumarin was explored. The azobenzene unit, attached to the coumarin chromophore at different positions via 3 and 8 carbon linkers, exhibited significant trans –cis isomerization upon UV irradiation at 365 nm, which affected both the absorption and fluorescence spectra of the coumarin part. The study demonstrated that the trans -to- cis transformation of the azobenzene moiety influences fluorescence intensity, with an increase observed in 7-hydroxycoumarin-derived compounds. However, for derivatives of 7-amino coumarin, the fluorescence intensity decreased. Density functional theory (DFT) and time-dependent DFT calculations suggested that the observed fluorescence changes are unrelated to the electronic coupling of the azobenzene and coumarin units. The increase in fluorescence is rather related to the absorption of excitation photons by trans azobenzene, and the decrease in fluorescence is due to the emitted photons absorbed by the azobenzene’s n – π* region.
Source: ACS Omega
Authors: Yasemin Akdis, Akin Akdag
Institution: Middle East Technical University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,935
OpenAlex ID: W4415270180