Methoxyl-modulated high-performance ratiometric fluorescent probe with AIE properties for hypochlorite detection and live cell imaging

Abstract

In recent years, the mechanism concerning fluorescence can be modulated by intramolecular charge transfer (ICT) effect has been widely used in the creation of ratiometric fluorescent probes. However, on this basis, further studies on the structure–activity relationship between molecular constitution of probes and their photophysical characteristics, as well as sensing performance remained less comprehensive. In this work, with triphenylamine (TPA) and methylthio as typical fluorophore and recognition groups respectively, an ICT-based hypochlorite (ClO⁻) fluorescent probe named Probe A was initially constructed, and then through ingenious molecular design, the second probe defined as Probe B was successfully prepared by introducing methoxyls as electron donors. The subsequent results showed that, compared with Probe A, the Probe B can exhibit superior aggregation-induced emission (AIE) properties and significant ratiometric fluorescence color change from blue to green within 4 min upon the addition of ClO⁻ in a 99 % water content system. Ultimately, the best performing Probe B was successfully applied to ClO⁻ detection in real water samples, the creation of portable test strips for naked-eye identification, and live cell imaging.