Novel hexapodal triazole linked to a cyclophosphazene core rhodamine-based chemosensor for selective determination of Hg2+ ions

The hexapodal Rhodamine B derivative compound 3 containing a cyclotriphosphazene core was synthesized and characterized by spectroscopic techniques such as FT-IR, H-1, C-13 and P-31 NMR, HR-MS, MALDI MS and microanalysis. Compound 3 is a naked eye selective sensor with colorimetric and fluorescent properties for Hg2+ ions in the presence of other metal ions such as Na+, K+, Ca2+, Ba2+, Mg2+, Ag+, Mn2+, Cu2+, Ni2+, Co2+, Pb2+, Cd2+, Zn2+, Fe2+, Fe3+, and Cr3+. 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 x 10(-9) M (0.75 ppb) for Hg2+ ions. The stoichiometry of compound 3-Hg2+ 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 S2- ion solutions.