Synthesis and Properties of Novel Dichroic Disazo Dyes Containing the Tetrafluoro-p-phenylene Moiety for Guest−Host Liquid Crystal Displays

Novel disazo dyes containing tetrafluoro -p- phenylene moiety(ies) have been synthesized. The absorption bands of these compounds were observed in the range of 432−555 nm in ZLI-4792. The introduction of tetrafluoro -p- phenylene moieties in both the terminal ends was very effective in increasing the solubility. The 4-butylthio derivative was most soluble among the 4-(butylthio)-, 4-(alkoxy)-, and 4-(butylamino)tetrafluoro -p- phenylene derivatives. The dichroisms of all the tetrafluoro -p- phenylene derivatives were similar ( S = 0.69−0.77) to those of the p -phenylene derivatives (0.68−0.76). These results indicate that the novel fluorine-containing disazo dyes can be practically used as dichroic dyes in guest−host liquid crystal displays.