Liquid crystalline dihydroazulene photoswitches

Anne Ugleholdt Petersen, Martyn Jevric, Richard J. Mandle, Edward J. Davis, Stephen J. Cowling, John W. Goodby, Mogens Brøndsted Nielsen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A large selection of photochromic dihydroazulene (DHA) molecules incorporating various substituents at position 2 of the DHA core was prepared and investigated for their ability to form liquid crystalline phases. Incorporation of an octyloxy-substituted biphenyl substituent resulted in nematic phase behavior and it was possible to convert one such compound partly into its vinylheptafulvene (VHF) isomer upon irradiation with light when in the liquid crystalline phase. This conversion resulted in an increase in the molecular alignment of the phase. In time, the meta-stable VHF returns to the DHA where the alignment is maintained. The systematic structural variation has revealed that a biaryl spacer between the DHA and the alkyl chain is needed for liquid crystallinity and that the one aromatic ring in the spacer cannot be substituted by a triazole. This work presents an important step towards employing the dihydroazulene-vinylheptafulvene photo/thermoswitch in photoactive liquid crystalline materials.

Original languageEnglish
Pages (from-to)89731-89744
Number of pages14
JournalRSC Advances
Issue number109
Publication statusPublished - 13 Oct 2015

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