Supramolecul enantiodifferentiating photoisomerization of (Z)-Cyclooctene in lyotropic and thermotropic liquid crystals

Debao Xiao, Takehiko Wada, Yoshihisa Inoue

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

In order to understand the roles of moderately organized media and the factors controlling the chirality transfer in supramolecular photochirogenesis, enantiodifferentiating photoisomerization of (Z)-cyclooctene to the chiral (E)-isomer (1E) has been performed for the first time in liquid crystal (LC)systems such as lyotropic LCs of poly(γ-benzyl-L-glutamate)(PBLG), difluorobenzene derivatives mixture, and thermotropic cholesteryl oleyl carbonate LCs. Basically, the as-employed LCs provided small enantiomer excess (<5%). It is interesting that lyotropic PBLG LCs give contrasting results in cholesteric and nematic mesophases, revealing the importance of the relevant mesophase structure of LC. Selective excitation in achiral difluorobenzene LC doped with a chiral sensitizer facilitates us to conclude that the LC's chiral spatial arrangement is not sufficient or suitable to induce appreciable enantiomeric excess (ee) in the product, but the existence of molecular chirality (of a chiral sensitizer) is essential to afford an optically active (nonracemic) product at least in the present photosensitization system. The photosensitizations in thermotropic LCs further reveal that the product's ee can be manipulated by the LC mesophase not directly but through the sensitizer's conformational changes induced by the supramolecular interactions with the surrounding LC structure.

Original languageEnglish
Pages (from-to)110-113
Number of pages4
JournalChirality
Volume21
Issue number1
DOIs
Publication statusPublished - 2009 Mar 2
Externally publishedYes

Keywords

  • Chiral photochemistry
  • Lyotropic liquid crystals
  • Photo-isomerization
  • Supramolecular-photosensitization
  • Thermolyopic liquid crystals

ASJC Scopus subject areas

  • Analytical Chemistry
  • Catalysis
  • Pharmacology
  • Drug Discovery
  • Spectroscopy
  • Organic Chemistry

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