Aggregated-induced emission phenothiazine probe for selective ratiometric response of hypochlorite over other reactive oxygen species

• A phenothiazine probe (QC1) with double dioxaborolane moieties was designed and synthesized.
• A stability phenothiazine was chosen as the report unit to avoid oxidant bleaching process.
• The fluorescent sensor (QC1) was designed for detecting ClO−.
• A new reaction and ratiometric signals for sensing HClO beyond other ROS.
• QC1 showed lower detection limited in absorption and fluorescent titration process.

In order to perform a ratiometric fluorescent sensor to recognize hypochlorite over other reaction oxidation species, a simple phenothiazine probe (QC1) with double dioxaborolane moieties was designed and synthesized. QC1 provided blue emission in aqueous and solid state. Double dioxaborolane and quaternary phosphonium salt was introduced into the molecule to prevent aggregation. The sulphur atom at the centre of phenothiazine was to respond to the hypochlorite at room temperature over other ROS because of its stronger oxidized ability. QC1 gave good linear fitting in the ratiometric mode under both absorption and emission titration experiments. Moreover, QC1 showed lower detection limited that reached 0.95 μM in absorption titration and 0.41 μM in fluorescent titration process.

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