Fig. 2. (A) The reaction of 4-amino-3-thiophenol-BODIPY 1a with propanal generates dihydrobenzothiazole 2a activating the fluorescence by hindering the PeT process. The quantum yields calculation of probe 1a and dihydrobenzothiazole adduct 2a showed 28-fold increase in the fluorescence in DMSO and 80-fold increase in the aqueous conditions. (B) High chemoselectivity of probe 1a towards varying types of aldehydes generating dihydrobenzothiazoles. No product was formed with other biological metabolites. *Dithiol was produced with SNAP by-product. (C) Pseudo-first order rate constant of probe 1a with propanal is 0.0196 s−1. (D) Limit of detection of probe 1a in detecting propanal in live T-47D cells. Letters indicate grouping by significance, P < 0.05.
