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Synthesis and characterization of M(II) (M = Cd, Hg and Pb) complexes with naphthodiaza-crown macrocyclic ligand and study of metal ion recognition by fluorescence, 1H NMR spectroscopy, and DFT calculation

Ghanbari, B ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1080/00958972.2016.1217332
  3. Publisher: Taylor and Francis Ltd
  4. Abstract:
  5. To find metal ion recognition by L (L = O2N2-donor naphthodiaza-crown macrocyclic ligand), the complexes [ML]2+ (M = Cd, Hg and Pb) were synthesized and characterized by IR, 1H, 13C NMR, and mass spectrometry, as well as elemental microanalysis. Hg(II) showed perceptible enhancement of the fluorescence of L in which ultra-low limit of detection for Hg(II) by L was determined as 1 nM in ethanol and DMSO. L reserved selectivity of Hg(II) in its binary mixtures with metal cations in solution. A 1 : 1 stoichiometry was found for the interaction of Hg(II) with L while Benesi–Hildebrand method was applied to calculate its complexation binding constant (K BH) employing fluorescence spectrophotometry. The monitoring of the chemical shifts in 1H NMR spectra of these complexes demonstrated that the central macrocycle of L was tailored for the size of Hg(II). Density functional theory calculations using B3LYP/6–31G* basis set demonstrated that the macrocycle cavity of L was properly fitted for complex formation with Hg(II) cation, while both Cd(II) and Pb(II) cations did not form strong bonds with L from inadequate cation size. The present study shows detection method of Hg(II) and also possible application of naphthodiaza as an appropriate fluorophore macrocyclic ligand for detecting other metal ions
  6. Keywords:
  7. Binding constant ; Chemosensor ; Fluorescence ; Metal ion recognition ; Naphthadiaza-crown
  8. Source: Journal of Coordination Chemistry ; Volume 69, Issue 18 , 2016 , Pages 2793-2803 ; 00958972 (ISSN)
  9. URL: http://www.tandfonline.com/doi/abs/10.1080/00958972.2016.1217332