Ionic Charge-Transfer Liquid Crystals Formed by Alternating Supramolecular Copolymerization of Liquid π-Donors and TCNQ

Hiroaki Iguchi, Hidenori Furutani, Nobuo Kimizuka

Research output: Contribution to journalArticlepeer-review

Abstract

A new family of liquid π-donors, lipophilic dihydrophenazine (DHP) derivatives, show remarkably high π-electron-donor property which exhibit supramolecular alternating copolymerization with 7,7,8,8-tetracyanoquinodimethane (TCNQ), giving ionic charge-transfer (ICT) complexes. The ICT complexes form distinct columnar liquid crystalline (LC) mesophases with well-defined alternating molecular alignment as demonstrated by UV-Vis-NIR spectra, IR spectra, and X-ray diffraction (XRD) patterns. These liquid crystalline ICT complexes display unique phase transitions in response to mechanical stress: the columnar ICT phase is converted to macroscopically oriented smectic-like mesophases upon applying shear force. Although there exist reports on the formation of ICT in the crystalline state, this study provides the first rational identification of ICT mesophases based on the spectroscopic and structural data. The liquid crystalline ICT phases are generated by strong electronic interactions between the liquid π-donors and solid acceptors. It clearly shows the significance of simultaneous fulfillment of strong π-donating ability and ordered self-assembly of the stable ICT pairs. The flexible, stimuli-responsive structural transformation of the ICT complexes offer a new perspective for designing processable CT systems with controlled hierarchical self-assembly and electronic structures.

Original languageEnglish
Article number657246
JournalFrontiers in Chemistry
Volume9
DOIs
Publication statusPublished - 2021 Mar 29

Keywords

  • ionic charge-transfer complex
  • liquid crystals
  • liquid donors
  • self-assembly
  • supramolecular alternate copolymerization

ASJC Scopus subject areas

  • Chemistry(all)

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