Self-complementary [2]catenanes and their related [3]catenanes

Beatriz Cabezon, Jianguo Cao, Françisco M. Raymo, J. Fraser Stoddart*, Andrew J P White, David J. Williams

*Corresponding author for this work

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

Three [3]catenanes with cavities large enough to accommodate aromatic guests have been designed and synthesized (yields = 5-20%) by means of kinetically controlled self-assembly processes. The X-ray structural analysis of one of three [3]catenanes confirmed the presence of a rectangular cavity (dimensions = 7 ×11 Å) lined by π-electron-rich recognition sites and hydro-gen-bond acceptor groups. In spite of their apparently ideal recognition features, none of these [3]catenanes bind guests incorporating a π-electron-deficient bipyridinium unit. However, the template-directed syntheses of the [3]catenanes also produce, in yields of 2-23%, [2]catenanes incorporating a l,5-dioxynaphtho[38]crown-10 inter-locked with a bipyridinium-based tetracationic cyclophane. The X-ray structural analyses of two of these [2]catenanes revealed that a combination of [π⋯π] and [C-H⋯π] interactions is responsible for the formation of supramolecular homodimers in the solid state. 1H NMR spectroscopic investigations of the four [2]catenanes demonstrated that supramolecular homodimers are also formed (Ka= 17-31M-1, T= 185 K) in (CD3)2CO solutions. Dynamic 1H NMR spectroscopy revealed that the 1,5-dioxynaphtho[38]crown-10 and tetracationic cyclophane components in the four [2]catenanes and in the three [3]catenanes circumrotate (ΔGC = 9-14 kcal mol-1) through each other's cavity in (CD3)2CO. Similarly, the 1,5-dioxynaphthalene and the bipyridinium ring systems rotate (ΔGc =10-14 kcalmol-1) about their [O⋯O] and [N ⋯ N] axes, respectively, in solution.

Original languageEnglish (US)
Pages (from-to)2262-2273
Number of pages12
JournalChemistry - A European Journal
Volume6
Issue number12
DOIs
StatePublished - Jun 16 2000

Keywords

  • Catenanes
  • Crystal engineering
  • Molecular recognition
  • Supramolecular chemistry
  • Template synthesis

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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