Proton-sensitive fluorescent organogels

Kazunori Sugiyasu, Norifumi Fujita, Masayuki Takeuchi, Sunao Yamada, Seiji Shinkai

Research output: Contribution to journalArticlepeer-review

105 Citations (Scopus)

Abstract

A 1,10-phenanthroline-appended cholesterol-based gelator (1) and its nongelling reference compound (2) were synthesized. Among 19 solvents tested herein, gelator 1 could gelate 11 solvents including alcohols, dipolar aprotic solvents, organic acids and a base (triethylamine), indicating that 1 acts as a versatile gelator. The TEM observation gave a visual image showing that fibrillar aggregates are entangled in the three-dimensional network structure. In the fluorescence measurements, most gels afforded an emission maximum at 394 nm (purple emission), whereas only the acetic acid gel afforded an emission maximum at 522 nm (yellow emission). Thus, the influence of protonation of the 1,10-phenanthroline nitrogens (by trifluoroacetic acid) on the fluorescence properties in the gel phase was investigated in detail. The results have established that the fluorescence intensity of 1·H+ becomes particularly strong in the gel phase, presumably because of the energy transfer from neutral 1* to protonated 1·H+ and the restriction of the 1·H+ molecular motion. The finding suggests the possibility that the gel system would be useful not only as a new proton-sensitive fluorescence system but also as a new medium for designing efficient energy transfer systems.

Original languageEnglish
Pages (from-to)895-899
Number of pages5
JournalOrganic and Biomolecular Chemistry
Volume1
Issue number5
DOIs
Publication statusPublished - 2003 Mar 7
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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