Fluorescence and Absorption Studies of the Cation-Binding Behavior of “Crowned” Liquid Crystals in Solution and in the Nematic Phase

Gong Xin He, Fumio Wada, Kiyoshi Kikukawa, Seiji Shinkai, Tsutomu Matsuda

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

4/-((p/-Cyanobiphenylyl)ethynyl)benzo crown ethers (3 and 4) not only display a nematic liquid-crystal phase but also show very strong fluorescence, both in solution and in the liquid-crystalline state. The “crowned” liquid crystal compound 4 exhibited a bathochromic shift in fluorescence and a hypsochromic shift in absorption with increasing solvent polarity. The addition of alkali-metal cations produced hypsochromic changes in both the fluorescence and absorption of 4. The cation-induced effects (fluorescence, absorption, and fluorescence quenching with thiocyanate salts) have been used as aids in determining the cation-binding ability of 4 in polar solvents, producing results similar to those obtained from conventional methods. On the basis of solution studies, the binding abilities of 3 and 4 in a eutectic nematic liquid crystal (ZLI-2806) were determined. The results revealed that 3 and 4 also complex alkali-metal cations selectively in the nematic phase, and the cation-binding ability is comparable with that found in methanol solution, but no evidence for 2:1 crown unit:cation complexation of 3 with KSCN was obtained under the present conditions. On the other hand, an energy-transfer quenching study with sodium 3-perylenecarboxylate under the same conditions did not show any specific cation-crown ether interaction.

Original languageEnglish
Pages (from-to)548-554
Number of pages7
JournalJournal of Organic Chemistry
Volume55
Issue number2
DOIs
Publication statusPublished - Jan 1 1990

All Science Journal Classification (ASJC) codes

  • Organic Chemistry

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