Trans-cis Photoisomerization of 1-Methyl-4-(4′-hydroxystyryl)pyridinium in inclusion complexes of β-cyclodextrin and its derivatives

Keita Hamasaki, Asao Nakamura, Akihiko Ueno, Fujio Toda

Research output: Contribution to journalArticle

4 Citations (Scopus)


The effects of β-cyclodextrin (β-CyD), heptakis(2,6-di-O-methyl)-β-cyclodextrin (DMβCyD) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TMβCyD) on trans-cis photoisomerization of 1-ethyl-4-(4′-hydroxystyryl)pyridinium (POH) have been studied in aqueous solutions. The ratio of [cis]/[trans] for POH in the photostationary state at pH 8.54 was remarkably reduced by the presence of βCyD or DMβCyD. The reduction of the [cis]/[trans] ratio in the photostationary state was explained in terms of the shift of the equilibrium of POH+trans ⇌ POtrans + H- toward POtrans formation. The binding constants of βCyD and DMβCyD for POtrans were 2.00- and 1.36-fold larger than those for POH+trans, respectively. The binding constants of TMβCyD for both species are much smaller than those of βCyD and DMβCyD. This result indicates that POtrans, which has a betain structure, forms stable complexes with βCyD and DMβCyD with its hydrophobic parts inside and the charged parts outside the CyD cavities.

Original languageEnglish
Pages (from-to)349-359
Number of pages11
JournalJournal of Inclusion Phenomena and Molecular Recognition in Chemistry
Issue number4
Publication statusPublished - 1992 Aug 1



  • 1-methyl-4-(4′-hydroxystyryl)pyridinium
  • betain
  • charge separation
  • cyclodextrin
  • inclusion complex
  • trans-cis photoisomerization

ASJC Scopus subject areas

  • Food Science
  • Chemistry(all)
  • Condensed Matter Physics

Cite this