Thiosemicabazone based fluorescent chemosensor for transition metal ions in aqueous medium

Highly efficient fluorescent chemosensors for metal ions have been synthesized by using thiosemicarbazide and aromatic aldehydes. Detection of transition metal ions was performed via UV-vis and fluorescence spectroscopic methods. This is the first report on thiosemicarbazone based sensor capable of detecting transition metal ions in aqueous medium. The binding constant, stoichiometry of the complex were confirmed by using B-H plot and Job's plot method. The fluorescence enhancement of thiosemicarbazones on binding with Hg2+, Zn2+, Co2+, Ni2+ and Sn2+ ions is due to the inhibition of photoinduced electron transfer mechanism whereas, quenching of fluorescence is attributed to the photoinduced electron transfer mechanism in case of Cu2+ and Mn2+ ions. (C) 2013 Elsevier B.V. All rights reserved.