Interplay of p-sulfonatocalix[4]arene and crown ethers en route to molecular capsules and "Russian Dolls"

Scott J. Dalgarno, Julie Fisher, Colin L. Raston

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

Diffusion-ordered 1HNMR spectroscopy techniques have been used to determine the binding strength of p-sulfonatocalix[4]arene (SO 3[4]) towards a number of charged crown ether species in aqueous conditions. For several (doubly) charged (di)azacrown ethers, all were bound by SO3[4] either well or very well with binding constants between 5.1 × 102-9.9 × 105M-1. These results correlate with, and thus explain the phenomenon of rapid capture of azacrown ethers in molecular capsules based on p-sulfonatocalix[4]arene and lanthanide metals. Similarly, the formation of "Russian doll" superanions in the solution phase is also elucidated. These superanions have been shown to selectively crystallise particular polynuclear aquated metal ions from mixtures in the aqueous phase. Neutral [18]crown-6 is not bound by p-sulfonatocalix[4] arene and displays a binding constant of 0M-1. When sodium [18]crown-6 is examined in a similar fashion, binding by SO3[4] is observed in solution with Ka∼ 3.1 × 103 M -1.

Original languageEnglish
Pages (from-to)2772-2777
Number of pages6
JournalChemistry - A European Journal
Volume12
Issue number10
DOIs
Publication statusPublished - 20 Mar 2006
Externally publishedYes

Keywords

  • Calixarenes
  • Crown compounds
  • Host-guest systems
  • NMR spectroseopy
  • Supramolecular chemistry

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