Pentaalkoxytriphenylene monoesters and their dyads; structural factors influencing columnar and nematic mesophase behaviour

ABSTRACT

Ester linkages are frequently employed in the design of discotic liquid crystals, and indeed the first examples of discotic liquid crystals reported by Chandrasekhar, Sadashiva and Suresh were hexaesters of benzene. Within the wide range of liquid crystalline triphenylene systems so far reported, the symmetrical hexa(aryl) esters are particularly noteworthy because they form the relatively rare and technologically important discotic nematic mesophase. An alternative strategy for inducing nematogenic behaviour is to build linked and twinned structures, and here we report examples of materials that combine the two design features. Pentahexyloxy triphenylenes bearing a single aryl ester retain the columnar mesophase. Linked dyad structures promote nematic phase formation and stability is influenced by the link type and bonding arrangement within isomeric series (phthalates) and related constructs.

Graphical Abstract

KEYWORDS:

• B. K. Sadashiva
• triphenylenes
• discotics
• synthesis
• nematic

Acknowledgments

We thank Princess Nourah Bint Abdul Rahman university, Taibah university, Technical and Vocational training corporation (Saudi Arabia) and TETFUND Nigeria for financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the TETFUND Nigeria; Technical and Vocational training corporation (Saudi Arabia); Princess Nourah Bint Abdul Rahman University; Taibah University.