Secondary dibenzylammonium ion binding by [24]crown-8 and [25]crown-8 macrocycles

Peter R. Ashton, Richard A. Bartsch, Stuart J. Cantrill, Robert E. Hanes, Sarah K. Hickingbottom, James N. Lowe, Jon A. Preece, J. Fraser Stoddart*, Vladimir S. Talanov, Zhen He Wang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


A range of crown ethers with either [24]crown-8 or [25]crown-8 constitutions have been demonstrated to form pseudorotaxanes with para- disubstituted dibenzylammonium ions, both in solution and in the 'gas phase' by 1H NMR spectroscopy and liquid secondary ion mass spectrometry, respectively. Substitution of the [24]crown-8 framework with increasing numbers of benzo rings is observed to lower the stability constants (K(a)'S) from >103 to ~0 M-1 in acetonitrile. A pronounced decrease in K(a) values also occurs when the [24]crown-8 constitution is expanded to give a macroring containing 25 atoms a modification that not only increases the size of the macrocyclic cavity but also disrupts the O-C-C-O repeating unit in the macrocycle's backbone.

Original languageEnglish (US)
Pages (from-to)3661-3664
Number of pages4
JournalTetrahedron Letters
Issue number19
StatePublished - May 7 1999


  • Crown ethers
  • Pseudorotaxanes
  • Substituted ammonium ion binding
  • Supramolecular chemistry

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry


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