1-(2-methoxybenzylidene)-4-phenylthiosemicarbazide as OFF-ON fluorescent chemodosimeter for detection of Cu2+ in acetonitrile-water binary solvents

A novel fluorescent chemodosimeter, 1-(2-methoxybenzylidene)-4-phenylthiolsemicarbazide, was studied. In 90:10 (v/v) mixture of CH3CN and water binary solution, it exhibits high selectivity toward Cu2+ but very low response toward other competitive cations. The Cu2+ promoting cyclization of the thiosemicarbazide to 1,2,4-triazole-3(4H)-thione ring results in observation of the turn-on fluorescence.