Pleochroic azo dyes, a liquid crystal composition containing the azo dyes and a display device using the liquid crystal composition

摘要

Pleochroic azo dyes represented by the formula (I): <IMAGE> (I) wherein X represents group -OCOR1 or -COOR1 (wherein R1 represents an alkyl group, an alkoxyalkyl group, an alkoxyphenyl group, an alkylcyclohexyl group, an alkoxyalkylcyclohexyl group, a cycloalkylcyclohexyl group, an alkoxycyclohexyl group, or a phenyl group substituted by a substituent selected from among an alkyl group containing 3 to 18 carbon atoms, an alkoxyalkyl group, a cycloalkyl group, an aryl group, a cyano group, a halogen atom, an acyloxy group, a carboxylic acid ester group, and an arylazo group); Y represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a cyano group, a carboxylic acid ester group, an acyloxy group, an alkylsulfonyl group, an aryl group, a halogen atom, or group <IMAGE> wherein R2 and R3 each represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, or R2 and R3 may be connected to each other to form a nitrogen-containing ring together with the adjacent nitrogen atom; Z1 to Z9 each represents a hydrogen atom, a halogen atom, a methyl group, a hydroxy group, a methoxy group or a cyano group, or Z1, Z2 and Z3 may be connected to R2 or R3 to form a nitrogen-containing ring, or Z1 and Z2, and Z4 and Z5, or Z7 and Z8 may be connected to each other to form an aromatic ring; at least one of <IMAGE> +TR <IMAGE> and n represents 0, 1 or 2, a liquid crystal composition containing the pleochroic azo dyes and a display device using the liquid crystal composition.