SYNTHESIS AND PROPERTIES OF NOVEL DICHROIC DISAZO DYES CONTAINING THETETRAFLUORO-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 observe d in the range of 432-555 nm in ZLI-4792. The introduction of tetraflu oro-p-phenylene moieties in both the terminal ends was very effective in increasing the solubility. The 4-butylthio derivative was most solu ble among the 4-(butylthio)-, 4-(alkoxy)-, and 4-(butylamino)tetrafluo ro-p-phenylene derivatives. The dichroisms of all the tetrafluoro-p-ph enylene derivatives were similar (S = 0.69-0.77) to those of the p-phe nylene derivatives (0.68-0.76). These results indicate that the novel fluorine-containing disazo dyes can be practically used as dichroic dy es in guest-host liquid crystal displays.