1,2-Di(phenylethynyl)ethenes with axially chiral, 2,2′-bridged 1,1′-binaphthyl substituents: Potent cholesteric liquid-crystal inducers

Yi Lin Wu, Fiammetta Ferroni, Silvia Pieraccini, W. Bernd Schweizer, Brian B. Frank, Gian Piero Spada, François Diederich*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    31 Scopus citations


    Axially chiral, 3,5-dihydro-4H-dinaphtho[2,1-c:1′,2′-e]azepine (dinaphthazepine) and 1,1′-binaphthyl-2,2′-disulfonimide (dinaphthosulfonimide) moieties were rigidly connected via N-p-phenylene linkers to photochemically (E)/(Z)-isomerisable 1,2-diethynylethene scaffolds. The chemical stability of the resulting systems was found to be critically related to the other substituents on the central π-conjugated scaffold. High helical twisting power (HTP), up to 315 μm-1, for the induction of a cholesteric liquid-crystalline phase through doping of a nematic phase was measured, resulting from the introduction of the chiral, mesogenic 1,1′-binaphthyl motifs. Single crystal X-ray analysis revealed that the phenylene spacer is in π-conjugation with the N-atom of the dinaphthazepine but not with the N-atom of the dinaphthosulfonimide moiety. This difference in orientation results in visible-transparency in the electronic absorption spectrum and higher (E)/(Z)-photoisomerisation quantum yields of the dinaphthosulfonimide-derived chiral dopants, as compared to the dinaphthazepine systems, which feature intramolecular charge-transfer absorption in the visible region.

    Original languageEnglish (US)
    Pages (from-to)8016-8026
    Number of pages11
    JournalOrganic and Biomolecular Chemistry
    Issue number39
    StatePublished - Oct 21 2012

    ASJC Scopus subject areas

    • Biochemistry
    • Physical and Theoretical Chemistry
    • Organic Chemistry


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