Metal ion complexation in acetonitrile by cone, di-ionised calix[4]arene-1,2-crown ethers with two pendant dansyl fluorophores


OCAK Ü. , OCAK M. , TU C., BARTSCH R. A.

SUPRAMOLECULAR CHEMISTRY, vol.23, no.11, pp.743-752, 2011 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 11
  • Publication Date: 2011
  • Doi Number: 10.1080/10610278.2011.626039
  • Title of Journal : SUPRAMOLECULAR CHEMISTRY
  • Page Numbers: pp.743-752

Abstract

Four cone calix[4]arene-1,2-crown ethers each with two ionisable side arms containing dansyl groups are synthesised. The crown ether ring on the lower rim is varied from crown-4 to crown-5 with hydrogen or tert-butyl groups on the para position of the upper rim. Di(tetramethylammonium) salts of the di-ionised ligands are utilised for spectrofluorimetric titration experiments in MeCN. The influence of alkali metal, alkaline earth metal and selected transition and heavy metal (Co2+, Fe2+, Hg2+, Mn2+, Pb2+, Zn2+ and Fe3+) cations on the spectroscopic properties of the two dansyl groups linked to the lower rim of the conformationally locked, di-ionised calix[4]arene-1,2-crown ether frameworks is investigated by emission spectrophotometry. All of the metal cations induce red shifts in the emission spectra of the di-ionised ligands. The metal cations produce enhancement or quenching of the fluorescence emissions. Changes in the fluorescence emission as a function of the metal cation identity, the lower rim crown ether ring size and the absence or presence of upper rim tert-butyl groups are investigated.