Stacking of conical molecules with a fullerene apex into polar columns in crystals and liquid crystals

Masaya Sawamura, Kenji Kawai, Yutaka Matsuo, Kiyoshi Kanie, Takashi Kato, Eiichi Nakamura

Research output: Contribution to journalArticlepeer-review

356 Citations (Scopus)

Abstract

Polar liquid crystalline materials can be used in optical and electronic applications, and recent interest has turned to formation strategies that exploit the shape of polar molecules and their interactions to direct molecular alignment1,2. For example, banana-shaped molecules align their molecular bent within smectic layers3, whereas conical molecules should form polar columnar assemblies4-9. However, the flatness of the conical molecules used until now4-6,9 and their ability to flip7,8 have limited the success of this approach to making polar liquid crystalline materials. Here we show that the attachment of five aromatic groups to one pentagon of a C60 fullerene molecule yields deeply conical molecules that stack into polar columnar assemblies. The stacking is driven by attractive interactions between the spherical fullerene moiety and the hollow cone formed by the five aromatic side groups of a neighbouring molecule in the same column. This packing pattern is maintained when we extend the aromatic groups by attaching flexible aliphatic chains, which yields compounds with thermotropic and lyotropic liquid crystalline properties. In contrast, the previously reported fullerene-containing liquid crystals10-17 all exhibit thermotropic properties only, and none of them contains the fullerene moiety as a functional part of its mesogen units. Our design strategy should be applicable to other molecules and yield a range of new polar liquid crystalline materials.

Original languageEnglish
Pages (from-to)702-705
Number of pages4
JournalNature
Volume419
Issue number6908
DOIs
Publication statusPublished - 2002 Oct 17
Externally publishedYes

ASJC Scopus subject areas

  • General

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