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Twisting Power (twisting + power)

Distribution by Scientific Domains
Chemistry100%

Kinds of Twisting Power

  • helical twisting power
    		•

    Selected Abstracts

    Bis-Chelated Imine-Alkoxytitanium Complexes: Novel Chiral Dopants with High Helical Twisting Power in Liquid Crystals

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2005
    Manfred Braun Prof. Dr.
    Abstract Enantiomerically and diastereomerically pure bis-chelated imine-alkoxytitanium complexes 6 and 7 have been synthesized and used as chiral dopants for converting nematic into cholesteric phases. The dopants were tested in mainly commercially available nematic liquid crystalline compounds or mixtures: LC1 (BASF), ZLI-1695 and ZLI-1840 (Merck), as well as N -(4-methoxybenzylidene)-4,-butylaniline (MBBA). The values of the helical twisting power (HTP) were determined by the Grandjean,Cano method. Exceptionally high helical twisting powers were obtained. Thus, the titanium complex 6,h displayed a HTP value of 740 ,m,1 in MBBA, the highest HTP value reported. The helical twisting power has been found to depend strongly on the structure of the nematic phase and the substitution pattern of the chiral ligand in the titanium complexes 6 and 7. Crystal structure analysis of 6,f confirmed the A,R,R configuration of the metal complex. The chiral imine ligands 4 and 5 were derived from the regioisomeric amino alcohols 1 and 2. [source]

    Reversible Full-Range Color Control of a Cholesteric Liquid-Crystalline Film by using a Molecular Motor

    CHEMISTRY - AN ASIAN JOURNAL, Issue 3 2006
    Rienk Eelkema Dr.
    Abstract By using a chiral molecular motor as a dopant in a cholesteric liquid-crystalline film, fully reversible control of the reflection color of this film across the entire visible spectrum is possible. The large difference in helical twisting power between the two isomeric forms of the motor allows efficient light- and heat-induced switching of the helicity of the cholesteric liquid-crystal superstructure. [source]

    Bis-Chelated Imine-Alkoxytitanium Complexes: Novel Chiral Dopants with High Helical Twisting Power in Liquid Crystals

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2005
    Manfred Braun Prof. Dr.
    Abstract Enantiomerically and diastereomerically pure bis-chelated imine-alkoxytitanium complexes 6 and 7 have been synthesized and used as chiral dopants for converting nematic into cholesteric phases. The dopants were tested in mainly commercially available nematic liquid crystalline compounds or mixtures: LC1 (BASF), ZLI-1695 and ZLI-1840 (Merck), as well as N -(4-methoxybenzylidene)-4,-butylaniline (MBBA). The values of the helical twisting power (HTP) were determined by the Grandjean,Cano method. Exceptionally high helical twisting powers were obtained. Thus, the titanium complex 6,h displayed a HTP value of 740 ,m,1 in MBBA, the highest HTP value reported. The helical twisting power has been found to depend strongly on the structure of the nematic phase and the substitution pattern of the chiral ligand in the titanium complexes 6 and 7. Crystal structure analysis of 6,f confirmed the A,R,R configuration of the metal complex. The chiral imine ligands 4 and 5 were derived from the regioisomeric amino alcohols 1 and 2. [source]