A novel ratiometric fluorescent sensor based on terpyridine derivatives for Zn²⁺ in aqueous solution

Terpyridine and its derivatives have good binding affinity for most transition metal ions due to the arrangement of their three pyridine nitrogen atoms. In this work, a new ratiometric fluorescent probe G, which is based on a styrylpyridinium attached to a terpyridine fluorophore, was synthesized and characterized. The fluorescence spectrum of probe G shows a good response to Zn2+ by an intramolecular charge transfer effect. On increasing the concentration of Zn2+, the fluorescence color of probe G changes from blue to yellow. Importantly, probe G has a high selectivity for Zn(2+)and is not affected by other metal ions, including Cd2+. In addition, the limit of detection (LOD) of probe G for Zn2+ was found to be up to 0.17 mu M. The results show that probe G has the ability to selectively recognize Zn2+ in aqueous solution.