Synthesis of perfluorobutyl-substituted ester-disazo dyes and their application to guest-host liquid crystal displays

Abstract

Ester-disazo dyes having perfluorobutyl and diethylamino groups in their molecules have been prepared. Their absorption maxima were observed in the range λ = 483–529 nm in a liquid crystal solvent. The solubility in terms of dye structure was in the order: monoesterdisazo >trisazo >diester-disazo. The solubility of the diester-disazo dyes in terms of the substituents at the terminal end was in the order: C₄F₉>C₄H₉>H. The introduction of the 4-diethylaminonaphthylene moiety was also effective in improving the solubility. The order parameter of the dye host systems was in order of the dye structures: trisazo >diesterdisazo >monoester-disazo. The order parameter for the diester-disazo dyes was calculated to be 0.79–0.82, high enough for practical use.