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AssigneeKabushiki Kaisha Suwa Seikosha
InventorsKatsumori Takei, Sadao Kanbe, Yoshio Shionozaki
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Ester compounds suitable for use in liquid crystal compositions are provided. The ester compounds are (2'-cyano-4'-alkylphenyl)-3-cyano-4-n-alkoxybenzoates represented by the general formula: ##STR1## wherein R and R' each is a straight-chain alkyl group having one to eight carbon atoms. The ester compounds alone do not exhibit a liquid crystal phase, but have a relatively low melting point. Addition of at least one such ester compound to a liquid crystal composition lowers the value of the dielectric anisotropy of the composition at frequencies higher than the critical frequency, and lowers it at frequencies lower than the critical frequency. Such compositions are particularly well suited for the two-frequency matrix-addressing drive in a display of complex characters or graphic displays. The ester compounds in accordance with the invention are prepared by condensing a 3-bromo-4-n-alkoxybenzoyl chloride having the general formula: ##STR2## and a 2-cyano-4-n-alkylphenol having the general formula: ##STR3## to prepare a (2'-cyano-4'-n-alkylphenol)-3-bromo-4-n-alkoxybenzoate having the general formula: ##STR4## wherein R and R' each is a straight-chain alkyl group having from one to eight carbon atoms, and reacting the benzoate (IV) with cuprous cyanide to yield the desired ester (I).
An ester compound represented by the general formula ##STR57## wherein each R and R' is selected from the group consisting of straight-chain alkyl groups having from one to eight carbon atoms for defining a (2'-cyano-4'-n-alkylphenyl)-3-cyano-4-n-alkoxybenzoate.
A liquid crystal composition comprising liquid crystal material including at least one frequency-dependent liquid crystal compound inducing a dielectric dispersion at lower frequency, admixed with at least one (2'-cyano-4'-alkylphenyl)-3-cyano-4-alkyloxbenzoate represented by the general formula:
A liquid crystal composition including at least one liquid crystal compound selected from the group consisting of:
A liquid crystal composition comprising:
A liquid crystal composition comprising:
Dependencies are inferred from the claim text.