A highly selective, pH-tolerable and fast-response fluorescent probe for Fe3+ based on star-shape benzothiazole derivative

A star-shape benzothiazole-based molecule TBB, obtained through a simple condensation reaction of 2-aminothiophenol with 1,3,5-benzenetricarboxylic acid in the presence of available catalyst polyphosphoric acid (PPA), has been exploited as a highly selective fluorescent Fe3+ probe over other metal ions in aqueous media (H2O/THF, v/v = 4/6). For this fast-response probe with a response time of 50 s, its quenching mechanism involving in the combination of static and dynamic quenching is confirmed by the test of time-correlated single photon counting (TCSPC) experiments. Noticeably, the probe TBB is suitable for Fe3+ detection in a wide pH range (3–12) of aqueous solution, and it can be successfully applied for Fe3+ quantitative measurement in real water samples.