Transition metal complexes of 4'-(p-nitrophenyl)-2,2':6',2"-terpyridine as fluorosensor sodium ion

Ligand 4'-(p-nitrophenyl)-2,2':6',2"-terpyridine has been synthesized using Krö hnke method by aldol condensation reaction. The solid brown precipitate was collected and resulted 40% yield. The ligand was characterized by ¹H-NMR spectrometer, IR spectrophotometer, elemental analyzer, UV-Vis spectrometer, and spectrofluorometer. The complexation of ligand was done by chelating method with transition metal (Cu²⁺, Zn²⁺). The complex compounds have been confirmed by UV-Vis spectrophotometer from absorbance spectrum data. The data showed a new peak at wavelength 236 nm for Cu²⁺ complex and 233 nm for Zn²⁺ complex. The application of ligand 4'-(p-nitrophenyl)-2,2':6',2"-terpyridine and complex compounds is as fluorosensor of sodium ion. The intensity of fluorescence was determined by spectrofluorometer. The addition of various concentrations of sodium ion into ligand and complex compounds (Cu²⁺, Zn²⁺) changed the intensity of fluorescence. The fluorescence data of ligand showed the on-off type while Cu and Zn complex showed the off-on type. The on-off type fluorescence was indicated by decreasing intensity and the off-on by increasing intensity. Both ligand and complex compound showed a wavelength shift when sodium ion was added into solution.