Photochromic and fluorescence switching behavior of triazole-functionalized fulgimides: Experimental and theoretical study
Loading...
Date
2026-05-11
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Luminescence
Abstract
Integrating photochromism and fluorescence switching within a single molecular platform remains a central
challenge in the development of light-regulated functional materials. Here, we report a structure-encoded design
strategy based on the direct covalent incorporation of a 1,2,4-triazole unit into the imide framework of fulgimides, yielding three new photoresponsive molecules (4E–6E). Experimentally, all compounds exhibit photochromism based on the interconversion between open and closed forms. This is accompanied by large visiblerange spectral contrast and reversible fluorescence ON/OFF switching under alternating UV and visible light.
The open-ring forms are strongly emissive, while photoinduced cyclization produces systematic fluorescence
quenching (20–40%) governed by intramolecular energy transfer to the conjugated closed-ring core. Density
functional and time-dependent DFT calculations quantitatively reproduce the observed experimental absorption
behavior and reveal pronounced π-delocalization and HOMO-LUMO gap narrowing upon ring closure, establishing clear structure–property relationships. Among the series, compound 6E shows the most favorable electronic and optical characteristics. These results identify triazole-imide coupling as a generalizable molecular
engineering route for multifunctional organic photo-switches and advance their potential for optical memory,
sensing, and adaptive photonic applications.
Description
Keywords
Photochromism, Fulgide, Fulgimide, Triazole, Fluorescence switch