A BODIPY-based fluorescent chemosensor with 2, 6-substitution for visual and highly selective detection of S 2 .

BODIPY derivatives have often been employed as fluorescent sensors to probe toxic ions in environment and living systems, such as sulfide ion (S ^2- ). Whilst many structure modifications have been exploited on groups at the 3, 5, 8-positions, there are quite few examples on tailoring the 2,6-substituents for chemosensor investigations. Herein, we design and synthesize a 2,6-substituted BODIPY molecule, LM-BDP, to use as a fluorescent probe for detecting S ^2- in aqueous media. The electronic and crystal structures of the probe are studied by density functional theory (DFT) calculations and single-crystal X-ray diffraction analysis. Spectroscopy investigations are performed in a variety of conditions, showing that LM-BDP exhibits a noticeable color change from pink to dark red and a fluorescence shift from yellow to pink channel with decreased intensity upon addition of S ^2- . The selectivity and sensitivity measurements show that LM-BDP can only response to S ^2- with a detection limit of 0.29 μM in less than 100 s. The remarkable contrast in fluorescence images in test-stripe and RAW 264.7 cell experiments indicates that the probe is a proper candidate for the application in detecting exogenous S ^2- .
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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