Plank-shaped column-forming mesogens with substituents on one side only

Edivandro Girotto, Marli Ferreira, Parantap Sarkar, Ahmed Bentaleb, Elizabeth A. Hillard, Hugo Gallardo, Fabien Durola, Harald Bock

    Research output: Contribution to journalArticlepeer-review

    12 Citations (Scopus)

    Abstract

    Abstract Prolonged glyoxylation of pyrenyl-1-glyoxylic acid ethyl ester leads to a mixture of isomers with polar pyrenylene-1,8-diglyoxylic acid as the main product, whereas the centrosymmetric 1,6-isomer is obtained in good yield from the corresponding dibromopyrene. Perkin condensations followed by Pd-catalyzed cyclizations lead to isomeric dinaphthopyrene-tetracarboxdiimides that self-assemble into columnar liquid crystals of hexagonal and rectangular symmetry, of which the rectangular mesophases have unusually elongated unit cells. The cisoid diimides with both alkylimide substituents on the same side of the oblong arene system show a much greater tendency to self-assemble into fluid stacks of disks than their centrosymmetric isomers. With racemically branched alkyl substituents, uniform vertical surface alignment of the columns in the high-temperature hexagonal mesophase is resilient to cycling through the lower-temperature rectangular and crystalline phases. On the same side: Dinaphthopyrene-diimides derived from 1,8-disubstituted pyrene, with both substituents on the same side, stack into columns to form hexagonal and rectangular liquid crystals and thus fully function as semi-flexible self-assembling disks (see figure). In contrast, their centrosymmetric isomers derived from 1,6-disubstituted pyrene are less prone to form liquid crystals.

    Original languageEnglish
    Pages (from-to)7603-7610
    Number of pages8
    JournalChemistry - A European Journal
    Volume21
    Issue number20
    DOIs
    Publication statusPublished - 2015 May 11

    Keywords

    • donor-acceptor systems
    • fused-ring systems
    • liquid crystals
    • phase transitions
    • self-assembly
    • stacking interactions

    ASJC Scopus subject areas

    • Catalysis
    • Organic Chemistry

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