Rotaxanes with chiral stoppers and photoresponsive central unit

Christopher Kauffmann, Walter M. Müller, Fritz Vögtle*, Sarah Weinman, Sarah Abramson, Benzion Fuchs

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Two new chiral and photoisomerizable rotaxanes (9m, 9p) have been prepared, beating the longest non-polymeric axle known so far: the axles (6m, 6p) are polyether chains made of alternating triethyleneglycol/hydroquinone units, bearing a central meta- or para-azobenzoyl moiety and terminal tetraacetylglucoside stopper groups, while the wheel is the cyclobis(p- xylylene)bis(4,4'-bipyridinium) salt. Temperature dependent 1H NMR measurements reveal that the translational process of the wheel across the azobenzene unit in the E-configuration is favoured for the para-rotaxane 9p compared to the meta isomer 9m. The azobenzene core of the free axles (6m, 6p) and rotaxanes (9m, 9p) undergo photochemical E/Z-isomerisation: from (E) to (Z) by irradiation at low wavelength and back from (Z) to (E) at high wavelength. Complete (Z) to (E) conversion was achieved by thermal isomerization.

Original languageEnglish
Pages (from-to)849-853
Number of pages5
Issue number5
StatePublished - 1999


  • Azobenzene isomerization
  • Chirality
  • Molecular recognition
  • Rotaxane
  • Supramolecular chemistry


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