Tetsuo Ozawa

Anthraquinone Dyes with Negative Dichroism

Abstract A number of α-substituted anthraquinone dyes with negative dichroism have been prepared. Observed order parameters range from—0.05 to—0.34. The results of this study are discussed in terms of the effect of the dye structure on the order parameters. From a survey of the results it is found that an amide group attached to the α-position of the anthraquinone nucleus plays a dominant role in producing negative dichroism. In addition, the spectroscopic data on the dyes are reported.

Order Parameters of β-Substituted Anthraquinone Dyes II: 1,4-Diaminoanthraquinone Derivatives

Abstract A study is presented of the optical order parameters and spectroscopic properties of 1,4-diaminoanthraquinone derivatives containing various substituents in the 2-position in a nematic liquid crystalline mixture composed of cyanophenylcyclohexane derivatives. The results are discussed in terms of the effects of the dye structure on the order parameters. By introducing a trans-4′-alkylcyclohexyloxycar-bonyl or aryloxycarbonyl group into the 2-position, blue dyes have been obtained which show high order parameters and solubilities.