Kinetic versus thermodynamic control during the formation of [2]rotaxanes by a dynamic template-directed clipping process

Matthias Horn, Johannes Ihringer, Peter T. Glink, J. Fraser Stoddart*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

80 Scopus citations

Abstract

A template-directed dynamic clipping procedure has generated a library of nine [2]rotaxanes that have been formed from three dialkylammonium salts - acting as the dumbbell-shaped components-and three dynamic, imino bond-containing, [24]crown-8-like macrocycles - acting as the ring-shaped components - which are themselves assembled from three dialdehydes and one diamine. The rates of formation of these [2]rotaxanes differ dramatically, from minutes to days depending on the choice of dialkylammonium ion and dialdehyde, as do their thermodynamic stabilities. Generally, [2]rotaxanes formed by using 2,6-diformylpyridine as the dialdehyde component, or bis(3,5-bis(trifluoromethyl)benzyl)ammonium hexafluorophosphate as the dumbbell-shaped component, assembled the most rapidly. Those rotaxanes containing this particular electron-deficient dumbbell-shaped unit, or 2,5-diformylfuran units in the macroring, were the most stable thermodynamically. The relative thermodynamic stabilities of all nine of the [2]rotaxanes were determined by competition experiments that were monitored by 1H NMR spectroscopy.

Original languageEnglish (US)
Pages (from-to)4046-4054
Number of pages9
JournalChemistry - A European Journal
Volume9
Issue number17
DOIs
StatePublished - Sep 5 2003

Keywords

  • Crown compounds
  • Dynamic covalent chemistry
  • Rotaxanes
  • Self-assembly
  • Supramolecular chemistry

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Organic Chemistry

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