A highly K(+)-selective phenylaza-[18]crown-6-lariat-ether-based fluoroionophore and its application in the sensing of K+ ions with an optical sensor film and in cells

Sandra Ast, Thomas Schwarze, Holger Müller, Aleksey Sukhanov, Stefanie Michaelis, Joachim Wegener, Otto S. Wolfbeis, Thomas Körzdörfer, Axel Dürkop, Hans Jürgen Holdt

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Herein, we report the synthesis of two phenylaza-[18]crown-6 lariat ethers with a coumarin fluorophore (1 and 2) and we reveal that compound 1 is an excellent probe for K(+) ions under simulated physiological conditions. The presence of a 2-methoxyethoxy lariat group at the ortho position of the anilino moiety is crucial to the substantially increased stability of compounds 1 and 2 over their lariat-free phenylaza-[18]crown-6 ether analogues. Probe 1 shows a high K(+)/Na(+) selectivity and a 2.5-fold fluorescence enhancement was observed in the presence of 100 mM K(+) ions. A fluorescent membrane sensor, which was prepared by incorporating probe 1 into a hydrogel, showed a fully reversible response, a response time of 150 s, and a signal change of 7.8% per 1 mM K(+) within the range 1-10 mM K(+). The membrane was easily fabricated (only a single sensing layer on a solid polyester support), yet no leaching was observed. Moreover, compound 1 rapidly permeated into cells, was cytocompatible, and was suitable for the fluorescent imaging of K(+) ions on both the extracellular and intracellular levels.

Original languageEnglish
Pages (from-to)14911-14917
Number of pages7
JournalChemistry (Weinheim an der Bergstrasse, Germany)
Issue number44
Publication statusPublished - 25 Oct 2013



  • crown compounds
  • fluorescence
  • gels
  • potassium
  • sensors

ASJC Scopus subject areas

  • Medicine(all)

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