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Synfacts 2007(11): 1147-1147  
DOI: 10.1055/s-2007-991279
Synthesis of Materials and Unnatural Products
© Georg Thieme Verlag Stuttgart · New York

Low-Temperature Discotic Nematic Liquid Crystals

Contributor(s):Timothy M. Swager, Ryan M. Moslin
S.-C. Chien, H.-H. Chen, H.-C. Chen, Y.-L. Yang, H.-F. Hsu*, T.-L. Shih, J.-J. Lee
Tamkang University, Tamsui and National Synchrotron Radiation Research Center, Hsin-Chu, Taiwan
Stable, Low-Temperature Discotic Nematic Superstructures by Incorporating a Laterally Substituted Sidearm in Hexakis(phenylethynyl)benzene Discogens
Adv. Funct. Mater.  2007,  17:  1896-1902  
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Publication History

Publication Date:
23 October 2007 (online)

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Key words

alkynylbenzenes - discotic liquid crystals - nematic liquid crystals

Significance

Replacement of one of the 6-symmetrical para-substituted aryl groups in the hexa­alkynylbenzene moiety with an aromatic ring possessing ‘lateral’ (ortho and/or meta) substitution gives disklike molecules that exhibit the discotic nematic (ND) liquid crystal (LC) phase. The authors are able to achieve low temperature (30 °C) non-columnar ND LC. It is likely that the large ortho substituents cause the laterally substituted aryl ring to twist out of plane. These same substituents then provide a steric barrier to column formation.

Comment

There are relatively few examples of ND liquid crystals; this is in contrast to the large number of calamitic (rod) nematic LCs, which make up the bulk of liquid crystal display (LCD) technology. By making simple but highly effective modifications to the well-established (see: Chimia 1987, 41, 196) hexaalkynylbenzene scaffold the authors have developed a variety of discotic LCs with good nematic properties. This technique is likely to find further use in the development of low-temperature ND liquid crystals.

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