Eu³⁺ complex of ligand4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine as fluorosensor of heavy metals

Ligand 4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine (2-Hcptpy) has been synthesized by modification of Kröhnke method. The synthesize was performed using aldol condensation reaction. The white precipitate was collected and produced 62% yield (1.062 gr). Ligand 2-Hcptpy has been characterized by FTIR, Elemental analyzer, H-NMR, UV-vis, and UV-DRS spectrometer. It was then reacted with lanthanide group (Eu³⁺) to form a complex by hydrothermal process. The result of Eu³⁺ complex was 0.352 gr. of white yellowish precipitate. The application of this research is for the fluorosensor of heavy metals (Pb²⁺dan Cd²⁺). The data of fluorescence showed two types of fluorescence, either turn on or turn off fluorosensor. Ligand 2-Hcptpy has an on-off type with the addition of Pb²⁺ and Cd²⁺, while complex Eu³⁺ has two types of fluorosensor. The complex showed turn on-off and turn on-off by addition of Pb²⁺ and type of turn off by addition of Cd²⁺. Either ligand or complex, showed fluorescence intensity by adding heavy metals up to concentration 5×10^-8 M.