Rotaxane or pseudorotaxane? That is the question!

Peter R. Ashton, Ian Baxter, Matthew C.T. Fyfe, Françisco M. Raymo, Neil Spencer, J. Fraser Stoddart, Andrew J.P. White, David J. Williams

Research output: Contribution to journalArticlepeer-review

256 Scopus citations


A series of secondary dialkylammonium ions (RCH2)2NH2+ have been prepared, and their binding properties toward the macrocyclic polyether dibenzo[24]crown-8 (DB24C8) evaluated. By using this information, a route to a kinetically stable rotaxane-like entity - stabilized by noncovalent bonding interactions between the DB24C8 macroring and the ammonium center - was established, in which the crown ether slips over a dialkylammonium ion's stopper groups (R). However, we have found that the kinetic stability of this rotaxane-like entity is extremely dependent on the nature of the solvent in which it is dissolved, suggesting that pseudorotaxanes lie in the fuzzy domain between two sets of extremes, wherein a beadlike macrocycle and a dumbbell-like component may either (1) exist as a rotaxane or (2) be completely disassociated from one another.

Original languageEnglish (US)
Pages (from-to)2297-2307
Number of pages11
JournalJournal of the American Chemical Society
Issue number10
StatePublished - Mar 18 1998
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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