A highly selective dual-channel chemosensor for mercury ions: utilization of the mechanism of intramolecular charge transfer blocking

Abstract

In this study, we developed a novel chemosensor (ATS) that contains the 5-(4-nitrophenyl)-2-furan group and α-naphthylamine for the dual-channel sensing of mercury ions. Under attack from mercury ions, the probe undergoes a blocked process; moreover, it broke the intramolecular charge transfer (ICT) state of the chemosensor, which can be confirmed by ¹H NMR, IR and MS studies. We designed this probe to produce a significant change in the color and fluorescence intensity that can achieve naked eye recognition. The experimental results proved that the 5-(4-nitrophenyl)-2-furan group is a very good chromophore. In addition, the ICT state inhibited the fluorescence of naphthylamine. The fluorescent intensity changed significantly when naphthylamine was released. Moreover, high selectivity experiments revealed that the fluorescent sensor is specific to mercury ions even with interference by high concentrations of other metal ions. The test strips based on ATS were fabricated, which could act as a convenient and efficient mercury ion test kit.