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Selective and sensitive fluorescent chemosensor based on N2O2-donor naphthodiaza-crown macrocyclic ligands for detection of Cu(II), and Zn(II)

Ghanbari, B ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jphotochem.2016.03.013
  3. Publisher: Elsevier B.V , 2018
  4. Abstract:
  5. Fluorescence spectroscopy of a series of N2O2-donor naphthodiaza-crown macrocyclic ligands, L1-L4, in ethanol revealed that Cu(II) cation had remarkable fluorescence quenching effect during complex formation with L2 and L3, while Zn(II) displayed noticeable enhancement on the fluorescence emission of L1 and L4, respectively. Fluorescence quantum yields of Ln (L1-L4) as well as their complexes Ln/M (II) (M = Cu, and Zn) were found as 0.11–0.34, respectively. The complementary experiments on determination of the limit of detection indicated (LOD) that L2 and L3 were highly selective for detection of Cu(II) while L1 and L4 were selective towards Zn(II), respectively. Using Benesi–Hildebrand equation, 1:1 stoichiometry was established for these complexes and their binding constants (KBH) for metal cations were obtained by employing fluorescence spectrophotometery. Moreover, these chemosensor ligands demonstrated selective detection of the Cu(II) and Zn(II) in the mixtures of different metal cations in the solution. The single crystal studies revealed that Cu(II) nitrate prefers ion paring with [H2L2]2+ instead of complex formation which consequently gave rise to the observed quenching of the emission band. Different mechanisms were suggested for the perceived fluorescence events of these macrocyclic ligands in the presence of Cu(II) and Zn(II). © 2016 Elsevier B.V
  6. Keywords:
  7. Binding constant ; Cation chemosensor ; Fluorescence ; Naphthadiaza-crown ; Quenching
  8. Source: Journal of Photochemistry and Photobiology A: Chemistry ; Volume 356 , 2018 , Pages 689-699 ; 10106030 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S1010603016000629