posted on 2018-11-26, 00:00authored byCláudia Brito da Silva, Eduarda Sangiogo Gil, Fabiano da Silveira Santos, Ana Moira Morás, Luiza Steffens, Paulo Fernando Bruno Gonçalves, Dinara Jaqueline Moura, Diogo Seibert Lüdtke, Fabiano Severo Rodembusch
This work describes
the synthesis of photoactive proton transfer
compounds based on the benzazolic core containing the azide group.
The compounds present absorption in the UV region and fluorescence
emission in the visible region of the spectra with large Stokes shift
due to a phototautomerism in the excited state (ESIPT). The azide
location on the benzazolic structure presented a noteworthy role on
their photophysics, leading to fluorescence quenching. A photophysical
study was performed in the presence of NaHS to evaluate their application
as an H2S sensor. The methodology employed was the reduction
of azides to amines using NaHS to mimic H2S, resulting
in an off–on response fluorescence mechanism. The observed
photophysical features were successfully used to explore the azides
as fluorescent probes in biological media. In addition, DFT and TD-DFT
calculations with the CAM-B3LYP/cc-pVDZ and CAM-B3LYP/jun-cc-pVTZ
level, respectively, were performed in order to understand the photophysics
features of azide derivatives, where the main interest was to investigate
the fluorescence quenching experimentally observed in the azide derivatives.