A new ratiometric fluorescent probe for sensing HOCl based on TBET in real time

•Imidazo[1,5-α]pyridine derivative is the first time to report as a TBET donor.•The probe can detect HOCl in 30 s.•The probe can detect HOCl with high selectivity and sensitivity.•The probe was applied to sensing HOCl in living cells with low toxicity.

A new ratiometric fluorescent probe (RPM) was developed based on through-bond energy transfer (TBET) mechanism for detecting hypochlorous acid. The probe was constructed from imidazo[1,5-a]pyridine as the energy donor and the rhodamine as the energy acceptor. The probe could be used to determine the concentration of HOCl with high selectivity and sensitivity (the detection limit = 2.08 × 10−6 M). In addition, RPM had a good time resolution for measuring HOCl with the response time of less than 30 s. Upon addition of HOCl, the fluorescence colors of probe RPM solution changed from green to red. Moreover, the probe has been successfully utilized for sensing HOCl in living cells.

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