title: Oxidative cyclization of thiosemicarbazone: an optical and turn-on fluorescent chemodosimeter for Cu(II).
abstract: A weakly fluorescent thiosemicabazone (L(1)H) was found to be a selective optical and "turn-on" fluorescent chemodosimeter for Cu(2+) ion in aqueous medium. A significant fluorescence enhancement along with change in color was only observed for Cu(2+) ion; among the other tested metal ions (viz. Na(+), K(+), Mg(2+), Ca(2+), Cr(3+), Zn(2+), Cd(2+), Hg(2+), Pb(2+), Ag(+), Ni(2+), Co(2+), Fe(3+) and Mn(2+)). The Cu(2+) selectivity resulted from an oxidative cyclization of the weak fluorescent L(1)H into highly fluorescent rigid 4,5-dihydro-5,5-dimethyl-4-(naphthalen-5-yl)-1,2,4-triazole-3-thione (L(2)). The signaling mechanism has been confirmed by independent synthesis with detail characterization of L(2).
authors.affiliation: Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
authors.forename: Arghya
authors.initials: A
authors.lastname: Basu
authors.forename: Gopal
authors.initials: G
authors.lastname: Das
mesh_terms: D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003500:Cyclization; D004578:Electron Spin Resonance Spectroscopy; D005456:Fluorescent Dyes / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet; D013882:Thiosemicarbazones / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D008670:Metals; D013882:Thiosemicarbazones; D003300:Copper