Thermal hysteresis exhibited by synthetic helical molecule: Memory effect at molecular level

Masanori Shigeno, Masahiko Yamaguchi

Research output: Contribution to journalArticlepeer-review

Abstract

Thermal hysteresis is a phenomenon, in which different responses occur during heating and cooling. Although bulk materials can exhibit thermal hysteresis by strong and multiple cooperative interactions between molecules, thermal hysteresis at molecular level in nonpolar organic solvents was essentially not known until now. We found that a chiral sulfonamido helicene tetramer forms a helix dimer in 1,3-difluorobenzene, which unfolds to a random coil on heating. This structural change exhibited thermal hysteresis, in which different structures of a helix dimer and a random coil were formed during heating and cooling at the same temperature. The phenomenon was explained by the different populations of helix dimers and random coils at the same temperature, and by the presence of induction periods. Thermal hysteresis is related to the "memory effect": the molecules memorize their thermal history, whether they were heated or cooled in the past. The model can also explain the "memory effect".

Original languageEnglish
Pages (from-to)511-512
Number of pages2
JournalKobunshi
Volume62
Issue number9
Publication statusPublished - 2013 Sep 1

Keywords

  • Helicenes
  • Helix Dimer
  • Induction Period
  • Memory Effect
  • Molecular Thermal Hysteresis
  • Sulfonamides

ASJC Scopus subject areas

  • Chemical Engineering(all)

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