Deterministic and Stochastic Chiral Symmetry Breaking Exhibited by Racemic Aminomethylenehelicene Oligomers

Yo Kushida, Tsukasa Sawato, Masanori Shigeno, Nozomi Saito, Masahiko Yamaguchi

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Racemic mixtures of aminomethylenehelicene (P)- and (M)-pentamers exhibited deterministic and stochastic chiral symmetry breaking during hetero-double-helix formation and self-assembly in solution. Heating a 50:50 mixture of (P)- and (M)-pentamers at 90 °C, and then cooling the mixture to 70 °C resulted in hetero-double-helix formation; a Cotton effect with negative Δε at λ=315 nm appeared. Chiral self-assembly occurred when the mixture was cooled to 25 °C. A strong tendency of deterministic chiral symmetry breaking appeared at the molecular and self-assembled levels, which was indicated by the negative Δε at λ=315 nm that appeared in most cases in repeated experiments. Mixtures containing 60:40 and 40:60 (P)-/(M)-pentamers also self-assembled with the same chirality. When a homo-double-helix (P)-/(M)-pentamer and a random coil (M)-/(P)-pentamer were mixed, the chiral self-assembly formed stochastically, and heating and cooling resulted in deterministic chiral symmetry breaking.

Original languageEnglish
Pages (from-to)327-333
Number of pages7
JournalChemistry - A European Journal
Volume23
Issue number2
DOIs
Publication statusPublished - 2017 Jan 1

Keywords

  • chiral symmetry breaking
  • circular dichroism
  • double helix
  • helicenes
  • self-assembly

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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