Novel hexapodal triazole linked to a cyclophosphazene core rhodamine-based chemosensor for selective determination of Hg(2+) ions.

The hexapodal Rhodamine B derivative compound 3 containing a cyclotriphosphazene core was synthesized and characterized by spectroscopic techniques such as FT-IR, (1)H, (13)C and (31)P NMR, HR-MS, MALDI MS and microanalysis. Compound 3 is a naked eye selective sensor with colorimetric and fluorescent properties for Hg(2+) ions in the presence of other metal ions such as Na(+), K(+), Ca(2+), Ba(2+), Mg(2+), Ag(+), Mn(2+), Cu(2+), Ni(2+), Co(2+), Pb(2+), Cd(2+), Zn(2+), Fe(2+), Fe(3+), and Cr(3+). The optical sensor properties of compound 3 were investigated using UV-vis and fluorescence spectroscopy. The lowest detection limit of compound 3 was determined as 3.76 × 10(-9) M (0.75 ppb) for Hg(2+) ions. The stoichiometry of compound 3-Hg(2+) complex was found to be 1:3 (ligand/metal ion). The reusable test strip was improved by the immobilization of compound 3 into a hydrogel network. The reusability of the sensor and test strip was tested with S(2-) ion solutions.