A turn-on fluorescent BOPHY probe for Cu2+ ion detection

Abstract

A new fluorine–boron compound BOPHY-PTZ was designed and synthesized. The fluorescent dye was used as a highly sensitive probe for Cu²⁺ ion detection. The mechanism of detection involved Cu²⁺ ion oxidation of the phenothiazine (PTZ) moiety and blocked the intramolecular charge transfer (ICT) process from the electron-donating PTZ moiety to the electron-accepting BOPHY moiety. BOPHY-PTZ showed a weak fluorescence in solution. However, it displayed a strong fluorescence signal enhancement upon the addition of Cu²⁺ ions, and 1.0 nM concentration of Cu²⁺ can be clearly detected. The assay is simple, sensitive and convenient, and it exhibits excellent selectivity for Cu²⁺ ions over the other metal ions. The BOPHY-PTZ probe could be used for Cu²⁺ ion detection in practical samples and for environmental monitoring related applications.