Phenylethylidene-3,4-dihydro-1H-quinoxalin-2-ones: Promising building blocks for Cu2+ recognition

Efrat Korin, Beny Cohen, Cheng Chu Zeng, Yi Sheng Xu, James Y. Becker

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

A series of sulfonamido-substituted phenylethylidene-3,4-dihydro-1H- quinoxalin-2-one derivatives in which both of the fluorophore and ionophore are integrated into one structural unit, have been investigated. They all exhibit high selectivity toward Cu2+ in ethanol in the presence of other metallic ions (Zn2+, Mg2+, Co2+, Ni 2+, Mn2+, Ca2+, and Ag+), as well as fast, stable, and reversible binding, as is evidenced by the observation of a red shift in the UV-vis spectrum, 'ON-OFF' fluorescence response. In addition, titration and MALDI-TOF measurements indicated that a 1:1 (and possibly also 2:1 (organic ligand: Cu2+) complexes were formed, depending on the relative amount of Cu2+ added to the solution of the organic ligand. It was also found that the binding constant could be tuned by modifying the nature and position of the substituents attached to the central benzene ring in the quinoxalone derivative. In acetonitrile, unlike in ethanol, these ligands undergo oxidation-decomposition by Cu2+ and therefore, no UV-vVis absorption bands could be observed. However, due to color change (from yellow to transparent) they could be useful as dosimeters in this solvent.

Original languageEnglish
Pages (from-to)6252-6258
Number of pages7
JournalTetrahedron
Volume67
Issue number34
DOIs
StatePublished - 26 Aug 2011

Keywords

  • Chemosensors
  • Cu recognition
  • Fluorescence
  • Quinoxalone derivatives

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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