A naphthalimide-derived hypochlorite fluorescent probe from ACQ to AIE effect transformation

In this work, by installing a free-rotating benzene ring to suppress the intermolecular π-π stacking effect in the aggregated state, a naphthalimide-derived hypochlorite (ClO^-) fluorescent probe, Probe A, with the aggregation-caused quenching (ACQ) effect was successfully transformed into Probe B possessing typical aggregation-induced emission (AIE) characteristics. The experimental results indicated that Probe B with good selectivity and a low detection limit (LOD) of 0.02 µM can also exhibit a significant ratiometric fluorescence color change from cyan to dark blue within 2 min in a nearly pure water solvent system after the addition of ClO^-. Finally, by virtue of the good photophysical properties and ClO^- sensing performance, Probe B and the Probe B loaded portable test paper were successfully applied to live cell imaging and the naked eye recognition of ClO^-, respectively.