A Benzothiazole-Based Sensor for Pyrophosphate (PPi) and ATP: Mechanistic Insight for Anion-Induced ESIPT Turn-On.

A benzothiazole derivative 2 bearing two 2,2'-dipicolylamine (DPA) groups was examined for its zinc-binding and subsequent anion sensing properties. The study revealed the anion sensing mechanism of polyphosphate anions via sequential binding to two zinc centers, on the basis of both 1H NMR and mass spectral evidences. The mechanistic insight would provide valuable information for the future design of new excited state intramolecular proton transfer (ESIPT) sensors. In addition, the zinc complex exhibited the solvent-switchible selectivity, responding to pyrophosphate (PPi) in EtOH but adenosine 5'-triphosphate (ATP) in water.