Zn2+/Cd2+ optical discrimination by fluorescent chemosensors based on 8-hydroxyquinoline derivatives and sulfur-containing macrocyclic units

M. C. Aragoni, M. Arca, Andrea Bencini, C. Caltagirone, A. Garau, F. Isaia, M. E. Light, V. Lippolis, C. Lodeiro, M. Mameli, R. Montis, M. C. Mostallino, A. Pintus, S. Puccioni

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Abstract

Four new fluorescent chemosensors for metal ions based on 8-hydroxyquinoline (8-HDQ) derivatives and sulfur-containing macrocyclic units were synthesized and characterized, namely 1-(5-chloro-8-hydroxy-7- quinolinylmethyl)-1-aza-4,7,10-trithiacyclododecane (L1), 1-(5-chloro-8-hydroxy- 7-quinolinylmethyl)-1-aza-4,13-dithia-7,10-dioxacyclopentadecane (L2), 1-(8-hydroxy-2-quinolinylmethyl)-1-aza-4,7,10-trithiacyclododecane (L3), and 1-(8-hydroxy-2-quinolinylmethyl)-1-aza-4,13-dithia-7,10-dioxacyclopentadecane (L4). Preliminary fluorimetric titrations indicated L1 as the only member of the family of ligands to give a selective CHEF-type response to the presence of Zn2+ in MeCN-H2O (1:1, v/v) solutions, which allowed imaging of this metal ion in Cos-7 cells in vitro. The other ligands either did not show any fluorescence response (L3, L4) to any of the metal ions considered (Cu2+, Zn2+, Cd2+, Hg2+ and Pb 2+) or gave (L2) a CHEF-type response also to the presence of Cd 2+. The coordination properties of L1 towards Zn2+ were, therefore, fully investigated by potentiometric measurements and absorption and emission spectroscopy at different pH values, which indicated that the formation of 2:1 L1/Zn2+ complexes is responsible for the CHEF-type effect observed. The complexes [Zn(L1)2H2O](BF4) 2 and [Zn(L3)](ClO4)2 were characterized in the solid state by X-ray crystallography, and DFT calculations were performed to understand the origin of the Zn2+/Cd2+ optical discrimination of the 8-HDQ-based "conjugate" fluorescent chemosensors reported. © 2013 The Royal Society of Chemistry.
Original languageEnglish
Pages (from-to)14516-14530
Number of pages15
JournalDalton Transactions
Volume42
Issue number40
DOIs
Publication statusPublished - 28 Oct 2013

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Keywords

  • 8-Hydroxyquinoline
  • 8-hydroxyquinoline derivatives
  • Absorption and emission spectroscopy
  • Coordination properties
  • DFT calculation
  • Fluorescent chemosensors
  • Fluorimetric titration
  • Potentiometric measurements
  • Emission spectroscopy
  • Fluorescence
  • Lead
  • Ligands
  • Metal ions
  • Physiology
  • Sulfur
  • X ray crystallography
  • Zinc
  • Copper
  • 8 quinolinol
  • cadmium
  • fluorescent dye
  • macrocyclic compound
  • sulfur
  • zinc
  • animal
  • chemical structure
  • chemistry
  • Chlorocebus aethiops
  • COS 1 cell line
  • light related phenomena
  • quantum theory
  • spectrofluorometry
  • synthesis
  • article
  • cell strain COS1
  • Animals
  • Cadmium
  • Cercopithecus aethiops
  • COS Cells
  • Fluorescent Dyes
  • Macrocyclic Compounds
  • Models, Molecular
  • Molecular Structure
  • Optical Processes
  • Oxyquinoline
  • Quantum Theory
  • Spectrometry, Fluorescence

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