[3+3]cycloalkyne dimers linked by an azo group: A stable cis-Azo compound forms polymeric aggregates by nonplanar π-π interactions

Yuto Saiki, Hiroki Sugiura, Keiichi Nakamura, Masahiko Yamaguchi, Tomonori Hoshi, Junichi Anzai

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

We previously reported that the structure of the linker moiety controlled intramolecular and bimolecular aggregation of [3+3]cycloalkyne oligomers, which are cyclic acetylene derivatives containing helicenes. Here, novel [3+3]cycloalkyne dimers linked by the azo group are synthesized, and aggregation behaviors are studied, which turned out to be considerably different. The trans- and cis-azo compounds were synthesized by the oxidative coupling of a [3+3]cycloalkyne amine derivative, and the stereochemistry was determined by UV-vis spectroscopy. 1H NMR, CD, gel permeation chromatography analysis, and vapor pressure osmometry in chloroform revealed that the trans-isomer forms a strong and selective bimolecular aggregate. The cis-isomer forms a trimolecular aggregate at a concentration below 1 mM and a polymeric aggregate at above 1 mM. Unlike known diaryl azo compounds, these azo isomers do not interconvert when subjected to heating or irradiation. In contrast, a model compound lacking the cyclic helicene structure isomerizes readily.

Original languageEnglish
Pages (from-to)9268-9269
Number of pages2
JournalJournal of the American Chemical Society
Volume125
Issue number31
DOIs
Publication statusPublished - 2003 Aug 6

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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