title: 2,1,3-Benzoxadiazole-based selective chromogenic chemosensor for rapid naked-eye detection of Hg2+ and Cu2+.
abstract: We report a simple twisted intramolecular charge transfer (TICT) chromogenic chemosensor for rapid and selective detection of Hg(2+) and Cu(2+). The sensor was composed of an electron-acceptor 4-fluoro moiety and an electron-donor 7-mercapto-2,1,3-benzoxadiazole species where the S together with the 1-N provided the soft binding unit. Upon Hg(2+) and Cu(2+) complexation, remarkable but different absorbance spectra shifts were obtained in CH(3)CN-H(2)O mixed buffer solution at pH 7.6, which can be easily used for naked-eye detection. The sensor formed a stable 2:1 complex with Cu(2+), and both 2:1 and 3:1 complexes with Hg(2+). While alkali-, alkaline earth- and other heavy and transition metal ions such as Na(+), Mg(2+), Mn(2+), Co(2+), Ni(2+), Ag(+), Zn(2+), Pb(2+) and Cd(2+) did not cause any significant spectral changes of the sensor. This finding is not only a supplement to the detecting methods for Hg(2+) and Cu(2+), but also adds new merits to the chemistry of 4,7-substituted 2,1,3-benzoxadiazoles.
authors.affiliation: Research Center for Analytical Sciences, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Tan
authors.forename: Xiu-Ping
authors.initials: XP
authors.lastname: Yan
mesh_terms: D000042:Absorption; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D002863:Chromogenic Compounds / Q000737:chemistry*; D003300:Copper / Q000032:analysis*; D005123:Eye; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000032:analysis*; D010069:Oxadiazoles / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D013997:Time Factors; D017186:Titrimetry; D014785:Vision, Ocular / Q000502:physiology*
chemical_list: C531568:4-(4-fluoro-2,1,3-benzoxadiazol-7-ylthio)-7-mercapto-2,1,3-benzoxadiazole; C531567:4-fluoro-7-mercapto-2,1,3-benzoxadiazole; D002863:Chromogenic Compounds; D010069:Oxadiazoles; D013438:Sulfhydryl Compounds; D013440:Sulfides; D003300:Copper; D008628:Mercury