title: A highly selective and sensitive Zn(II) complex-based chemosensor for sequential recognition of Cu(II) and cyanide.
abstract: Two new Schiff base complexes, [ZnL(Ac)]2 (1) and [CuLCl]·H2O (2) (HL = 2-(2'-hydroxynaphthylmethylene)aminophenylbenzimidazole, Ac = acetate) were synthesized by a one-pot reaction and characterized by elemental analyses, IR and single-crystal X-ray diffraction. Fluorescence of complex 1 showed "on-off-on" switching when Cu(2+) and cyanide were sequentially detected. This phenomenon was investigated by UV-Vis absorption, fluorescence and ESI-MS spectra, and theoretical calculations to explain the response. Complex 1 can selectively respond to Cu(2+) with the fluorescence "turn-off" owing to the formation of complex 2 in the solution. Interestingly, the quenched fluorescence of complex 1 by Cu(2+) ions could be turned on after the addition of cyanide owing to the displacement of L(-) by CN(-) to form [Cu(CN)x](n-), making complex 1 a selective CN(-) probe. In addition, the results of the MTT assay experiment indicate that complex 1 has a low toxicity to cells and can be used to detect intracellular Cu(2+) ion by live cell imaging.
authors.affiliation: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing, 100875, People's Republic of China. xjzheng@bnu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.forename: Xiang-Jun
authors.initials: XJ
authors.lastname: Zheng
authors.forename: De-Cai
authors.initials: DC
authors.lastname: Fang
authors.forename: Lin-Pei
authors.initials: LP
authors.lastname: Jin
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D003300:Copper / Q000032:analysis*; D018360:Crystallography, X-Ray; D003486:Cyanides / Q000032:analysis*; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D008968:Molecular Conformation; D011789:Quantum Theory; D012545:Schiff Bases / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet; D015032:Zinc / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D003486:Cyanides; D012545:Schiff Bases; D003300:Copper; D015032:Zinc