Dichroic azo dyestuffs and liquid crystal composition containing said dyestuffs
AssigneeMitsui Toatsu Chemicals, Inc.
InventorsKeisuke Takuma, Kimitoshi Kato, Hiroshi Aiga, Yasuyuki Yamada, Tsutomu Nishizawa
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Abstract
Provided are novel dichroic azo dyestuffs, which contain skeletons represented by the following general formula: ##STR1## at one terminals of the long axes of the molecules of the azo dyestuffs, and liquid crystal compositions containing the dichroic azo dyestuffs in forms dissolved in liquid crystals. These dichroic azo dyestuffs have large dichroic ratios and high durability, and their compositions are employed as useful display devices.
Claims17
A dichroic azo dyestuff represented by the following formula:
- ##STR175## wherein A is --CN, --COOR.sub.1, ##STR176## R.sub.1 is alkyl, alkoxyalkyl, phenyl, cyclohexyl, or phenyl or cyclohexyl which are substituted with alkyl or alkoxy at the p-position thereof;
- R.sub.2 and R.sub.3 are individually hydrogen alkyl, cycloalkyl, alkoxy, alkoxyalkoxy, cycloalkyloxyalkoxy, aryloxyalkoxy, aryl, halogen, cyano or dialkylamino;
- Y.sub.1 and Y.sub.2 are individually hydrogen, halogen, alkyl, alkoxy, cyano or hydroxyl;
- Ar.sub.1 and Ar.sub.2 are individually ##STR177## W.sub.1 and W.sub.2 are individually --N.dbd.N-- or --N.dbd.CH--, but W.sub.1 is --N.dbd.N-- when W.sub.2 is --N.dbd.CH--, m is 0 or 1, but m is 0 when W.sub.1 is --N.dbd.CH--;
- and B is hydroxyl, alkoxy, alkoxyalkoxy, p-alkylbenzyloxy, ##STR178## but B is hydrogen, halogen, cyano, ##STR179## when W.sub.1 or W.sub.2 is --N.dbd.CN--, R.sub.4 is alkyl, phenyl or cyclohexyl unsubstituted or substituted with alkyl or alkoxy at the p-position thereof, R.sub.5 is hydrogen or alkyl, R.sub.6 is alkyl or ##STR180## R.sub.7 and R.sub.8 are individually hydrogen, halogen, hydroxyl, cyano, alkyl, dialkylamino, alkoxy, alkoxyalkoxy, ##STR181## and R.sub.9 is hydrogen or alkyl.
A liquid crystal composition containing, in a form dissolved in a liquid crystal, at least one of dichroic azo dyestuffs represented by the following formula:
- ##STR193## wherein A is --CN, --COOR.sub.1, ##STR194## R.sub.1 is alkyl, alkoxyalkyl, phenyl, cyclohexyl, or phenyl or cyclohexyl which are substituted with alkyl or alkoxy at the p-position thereof;
- R.sub.2 and R.sub.3 are individually hydrogen, alkyl, cycloalkyl, alkoxy, alkoxyalkoxy, cycloalkyloxyalkoxy, aryloxyalkoxy, aryl, halogen, cyano or dialkylamino;
- Y.sub.1 and Y.sub.2 denote individually hydrogen;
- halogen, alkyl, alkoxy, cyano or hydroxyl;
- Ar.sub.1 and Ar.sub.2 are individually ##STR195## W.sub.1 and W.sub.2 are individually --N.dbd.N-- or --N.dbd.CH--, but W.sub.1 is --N.dbd.N-- when W.sub.2 is --N.dbd.CH--, m is 0 or 1, but m is 0 when W.sub.1 is --N.dbd.CH--;
- and B is hydroxyl, alkoxy, alkoxyalkoxy, p-alkylbenzyloxy, ##STR196## but B is hydrogen, halogen, cyano, ##STR197## when W.sub.1 or W.sub.2 is --N.dbd.CN--, R.sub.4 is alkyl, phenyl or cyclohexyl unsubstituted or substituted with alkyl or alkoxy at the p-position thereof, R.sub.5 is hydrogen or alkyl, R.sub.6 is alkyl or ##STR198## R.sub.7 and R.sub.8 are individually hydrogen, halogen, hydroxyl, cyano, alkyl, dialkylamino, alkoxy, alkoxyalkoxy, ##STR199## and R.sub.9 is hydrogen or alkyl.
Dependencies are inferred from the claim text.