Selective binding of imidazolium cations in building multi-component layers

Irene Ling, Yatimah Alias, Alexandre N. Sobolev, Lindsay T. Byrne, Colin L. Raston

Research output: Contribution to journalArticleResearchpeer-review

16 Citations (Scopus)

Abstract

Addition of l-alkyl-3-methyl-imidazolium (Cn-mim) cations 3-5 to a mixture of bis-phosphonium cation 2 and sodium p-sulfonatocalix[4]arene (1) in the presence of lanthanide ions results in the selective binding of an imidazolium cation into the cavity of the calixarene. The result is a multi-layered solid material with an inherently flexible interplay of the components. Incorporating ethyl-, n-butyl- or nhexyl-mim cations into the multi-layers results in significant perturbation of the structure, the most striking effect is the tilting of the plane of the bowl-shaped calixarene relative to the plane of the multi-layer, with tilt angles of 7.2, 28.9 and 65.5°, respectively. The lanthanide ions facilitate complexation, but are not incorporated into the structures and, in all cases, the calixarene takes on a 5- charge, with one of the lower-rim phenolic groups deprotonated. ROESY NMR experiments and other 1H NMR spectroscopy studies establish the formation of 1:1 supermolecules of Cn-mim and calixarene, regardless of the ratio of the two components, and indicate that the supermolecules undergo rapid exchange on the NMR spectroscopy timescale.

Original languageEnglish
Pages (from-to)6973-6982
Number of pages10
JournalChemistry - A European Journal
Volume16
Issue number23
DOIs
Publication statusPublished - 18 Jun 2010
Externally publishedYes

Keywords

  • Bis-phosphonium cations
  • Calixarenes
  • Host-guest systems
  • Imidazolium cations

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