Ligand 4'-(4-carboxyphenyl)-2,2':6',2"-terpyridine grafted with TiO₂–complexation with the ions metal transition and application as fluorosensor for Na⁺ ion

Ligand 4'-(4-Carboxyphenyl)-2,2':6',2"-Terpyridine (Hcptpy) has been synthesized using reaction of aldol condensation. The result was white-yellowish precipitate with yield of 62%. The Ligand hcptpy was grafted with TiO₂ by mass ratio 0.15 : 1 (wt/wt). The Hcptpy-TiO₂ was reacted in complexation reaction with transition metals (Fe, Mn, Ni) by chelating method, with the best mole chelating ratio of 0.15 : 1 (mole/mole). The ligand Hcptpy, Hcptpy-TiO₂ and complex assembly M-Hcptpy-TiO₂ were characterized by CHN Analyzer, HNMR, FT-IR, UV-VIS, and UV-DRS. The application of this research was to apply it as fluorosensor for sodium metal ion in sodium chloride. The study was conducted by spectrofluorometer. Types of fluoroscent for sodium metal ion detection are Chelation Quenching Effect (on-off signal) and the Chelation Enhanced Fluoroscence effect (off-on signal). The type of on-off signal causes a quenching in fluoroscence intensity, while the off-on signal causes an increase in fluoroscence intensity. The result showed that Hcptpy-TiO₂, Ni-Hcptpy-TiO₂ were the off-on fluoroscence type with the ability to respond the presence of sodium ion at concentration 3 × 10^-10 M and 3 × 10^-9M, respectively. While Mn-Hcptpy-TiO₂ and Fe-Hcptpy-TiO₂ were the on-off signal type with the ability to respond the presence of sodium metal ion at concentration 3 × 10^-8 M and 3 × 10^-8 M, respectively. The process of sodium metal ions detection was carried out by substitution reaction of metal ion in complex with sodium metal ions. (paper)