Chemosensor properties of 7-hydroxycoumarin substituted cyclotriphosphazenes

The newly synthesized cyclotriphosphazene cored coumarin chemosensors 5, 6, and 7 were successfully characterized by ¹ H NMR, ³¹ P NMR, and MALDI-TOF mass spectrometry. Additionally, the photophysical and metal sensing properties of the targeted compounds were determined by fluorescence spectroscopy in the presence of various metals (Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Cr ³⁺ , Mn ²⁺ , Fe ³⁺ , Co ²⁺ , Al ³⁺ , Hg ⁺ , Cu ²⁺ , Zn ²⁺ , Ag ⁺ , and Cd ²⁺ ) . The fluorescence titration results showed that compounds 5, 6, and 7 could be employed as fluorescent chemosensors for Fe ³⁺ ions with high sensitivity. The complex stoichiometry between final cyclotriphosphazene chemosensors and Fe ³⁺ ions was also determined by Job's plots.