A Turn-on Fluorescent Sensor for Pyrophosphate Based on the Disassembly of Cu²⁺-Mediated Perylene Diimide Aggregates

A complex between an anionic perylene diimide derivative (PDI-GlyAsp) and cupric ion has been prepared and applied to be turn-on fluorescent probe for the detection of pyrophosphate (PPi) in 100% aqueous solution. The complex formation process and PPi detection have been studied by absorption and emission spectroscopy. It was confirmed that the introduction of cupric ion into PDI-GlyAsp solution resulted in the assembly of PDI-GlyAsp into PDI-GlyAsp/Cu²⁺ aggregates, leading to the fluorescence quenching of PDI-GlyAsp. Upon addition of PPi into the above solution led to the disassembly of the aggregates due to the competitive binding of PPi with Cu²⁺ in the PDI-GlyAsp/Cu²⁺ complex, and a recovery of PDI-GlyAsp emission was observed. Therefore, the PDI-GlyAsp/Cu²⁺ complex can be applied as a turn-on fluorescent probe for detecting PPi with high selectivity and sensitivity