Photoinduced Polarization Inversion in a Ferroelectric Liquid Crystal Using an Ambidextrous Chiral Thioindigo Dopant

• Published in: Journal of the American Chemical Society Vol. 125; no. 23; pp. 6862 - 6863
• Main Authors: Vlahakis, Jason Z, Wand, Michael D, Lemieux, Robert P
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 11.06.2003; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Physical Sciences; Physics; Polymers; organic compounds; Science & Technology; PHOTOCHEMICAL CONTROL; DESIGN; ISOMERIZATION; Benzoic acid derivatives; Temperature dependence; Indigoid dye; Photoisomerization; Visible radiation; Benzenic compound; Ferroelectric liquid crystals; Experimental study; Spontaneous polarization; Organic compounds; Ultraviolet visible spectrometry
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0353309

In this Communication, we report the first example of photoswitching of a ferroelectric SmC* liquid crystal based on a photoinduced sign inversion of the spontaneous polarization (P S) induced by a single chiral dopant. This is achieved without concomitant destabilization of the SmC* phase using the “ambidextrous” dopant 6-((R,R)-2,3-difluorooct-1-yloxy)-5‘-nitro-6‘-((R)-2-octyloxy)thioindigo. The (R)-2-octyloxy side chain is sterically coupled to the thioindigo core via the nitro substituent and induces a positive polarization, whereas the (R,R)-2,3-difluorooct-1-yloxy side chain is decoupled from the core and induces a negative polarization. With this new design, the increase in transverse dipole moment of the thioindigo core upon trans−cis photoisomerization raises the polarization power of the coupled 2-octyloxy/thioindigo unit above that of the 2,3-difluorooctyloxy unit and inverts the net sign of P S.