Constructing a novel “turn-on” fluorescent sensor based on phenazine macrocycle through halogen bond interaction for the naked-eye detection of phenylenediamine isomers

Developing a visual color change pathway to differentiate and identify three phenylenediamine isomers remains an extremely fascinating and critical task. Herein, we first reasonably introduced iodine molecule(I2) to regulate the stimuli-responsive properties of phenazine macrocycle(PNH), and thus a novel “turn-on” fluorescence sensing platform(PNH-I2) was constructed through intermolecular halogen bonding. This platform PNH-I2 enabled nakey-eye identification and ultra-sensitive detection of o-phenylenediamine(OPD), m-phenylenediamine(MPD) and p-phenylenediamine(PPD) at low concentration levels(2 μM). The lowest detection limits(LODs) for OPD and MPD reached 6.97 × 10-9 M and 2.90 × 10-9 M, respectively, which were much lower than those reported literatures. More importantly, the test box based on PNH-I2 could be used as intelligent fluorescence display material, which had good application value in the detection and identification of three phenylenediamine isomers. Moreover, the fluorescence sensor PNH-I2 could successfully perceive the presence of OPD and MPD in real water sample. Such a novel strategy is expected to open up new applications of phenazine derivatives in environmental science.