AUTHOR=Frizon Tiago E. A. , Vieira André A. , da Silva Fabricia N. , Saba Sumbal , Farias Giliandro , de Souza Bernardo , Zapp Eduardo , Lôpo Michell N. , Braga Hugo de C. , Grillo Felipe , Curcio Sergio F. , Cazati Thiago , Rafique Jamal TITLE=Synthesis of 2,1,3-Benzoxadiazole Derivatives as New Fluorophores—Combined Experimental, Optical, Electro, and Theoretical Study JOURNAL=Frontiers in Chemistry VOLUME=8 YEAR=2020 URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00360 DOI=10.3389/fchem.2020.00360 ISSN=2296-2646 ABSTRACT=
Herein, we report the synthesis and characterization of fluorophores containing a 2,1,3-benzoxadiazole unit associated with a π-conjugated system (D-π-A-π-D). These new fluorophores in solution exhibited an absorption maximum at around ~419 nm (visible region), as expected for electronic transitions of the π-π* type (ε ~2.7 × 107 L mol−1 cm−1), and strong solvent-dependent fluorescence emission (ΦFL ~0.5) located in the bluish-green region. The Stokes' shift of these compounds is ca. 3,779 cm−1, which was attributed to an intramolecular charge transfer (ICT) state. In CHCl3 solution, the compounds exhibited longer and shorter lifetimes, which was attributed to the emission of monomeric and aggregated molecules, respectively. Density functional theory was used to model the electronic structure of the compounds