Hoffmann-la Roche Inc.

Rolic Ag

Alfred Germann

Martin Schadt

Richard Buchecker

Alois Villiger

Arthur Boller

Stephen Kelly

Martin Petrzilka

Hanspeter Scherrer

Flourobenzyl ether derivatives of the formula ##STR1## and liquid crystalline mixtures which contain such compounds are prepared and employed in electro-optical display devices.

Fluorobenzyl ether derivatives

Compounds of the formula ##STR1## wherein Z.sup.1 denotes a single covalent bond or --CH.sub.2 Ch.sub.2 --; ring A.sup.1 represents 1,4-phenylene, pyrimidine-2,5-diyl, pyridine-2,5-diyl or, when Z.sup.1 stands for --CH.sub.2 CH.sub.2 --, also trans-1,4-cyclohexylene; X.sup.1 stands for fluorine or chlorine; X.sup.2 signifies fluorine, chlorine or hydrogen, with the proviso that X.sup.2 only signifies hydrogen when X.sup.1 is chlorine or when ring A.sup.1 signifies pyridine-2,5-diyl and Z.sup.1 signifies --CH.sub.2 CH.sub.2 --; and R.sup.1 signifies 1E-alkenyl with 2 to 12 carbon atoms, their manufacture, liquid crystalline mixtures which contain these compounds and their use for electro-optical purposes.

Alkenylcyclohexane liquid crystalline compounds

Compounds of the formula ##STR1## wherein Z.sup.1 is a single covalent bond or --CH.sub.2 CH.sub.2 --, X.sup.1 is hydrogen, fluorine or chlorine and R.sup.1 is 1E-alkenyl with 2 to 12 carbon atoms, their preparation, liquid crystalline mixtures which contain these compounds and their use for electro-optical purposes.

Bicyclohexyl derivatives

There is described compounds of the formula ##STR1## wherein X stands for CH and Y stands for N or X stands for N and Y stands for CH; A.sup.1 and A.sup.2 signify single covalent bonds or one of the groups A.sup.1 and A.sub.2 also signifies trans-1,4-cyclohexylene, cis-4-cyano-trans-1,4-cyclohexylene or 1,4-phenylene optionally substituted with halogen or methyl; ring B represents trans-1,4-cyclohexylene, 1,4-phenylene optionally substituted with halogen or methyl or, when A.sup.2 signifies a single covalent bond, also cis-4-cyano-trans-1,4-cyclohexylene; R.sup.1 denotes an optionally halogen-substituted alkyl or alkenyl group in which optionally one CH.sub.2 group or two non-adjacent CH.sub.2 groups is/are replaced by --O--, --COO-- and/or --OOC--; R.sup.2 signifies an optionally halogen-substituted alkyl or alkenyl group in which optionally one CH.sub.2 group or two non-adjacent CH.sub.2 groups is/are replaced by --O--, --COO-- and/or --OOC-- or R.sup.2 on a benzene ring also signifies --NCS, cyano or halogen; with the proviso that R.sup.1 denotes an optionally halogen-substituted alkenyl group in which optionally one CH.sub.2 group or two non-adjacent CH.sub.2 groups is/are replaced by --O--, --COO-- and/or --OOC-- when R.sup.2 signifies cyano or halogen; and with the proviso that R.sup.1 and/or R.sup.2 has a chiral carbon atom when R.sup.1 and R.sup.2 stand for optionally halogen-substituted alkyl groups in which optionally one CH.sub.2 group or two non-adjacent CH.sub.2 groups is/are replaced by --O--, --COO-- and/or --OOC--, as well as liquid crystalline mixtures and their use for electro-optical purposes.

Pyridine liquid crystalline compounds

Coloring substance-containing liquid crystal mixtures

Liquid crystal mixtures containing a coloring substance which comprise about 5 to about 40 weight % of trans-p-[5-(4-alkylcyclohexyl)-2-pyrimidinyl]benzonitriles, about 10 to about 60 weight % of trans-4-alkylcyclohexane carboxylic acid phenyl esters and about 0.1 to about 15 weight % of one or more coloring substances of the formula ##STR1## wherein m stands for the number 1 and X is alkoxy and Y is nitro; or m stands for the number 1 or 2; and X is p-alkoxyphenyl and Y is nitro or dialkylamino, or X is alkoxy and Y is -p-nitrophenyl or -(dialkylamino)phenyl; or m stands for the number 2, and X is alkoxy and Y is alkoxy, nitro or dialkylamino, or both X and Y are dialkylamino; and wherein the alkoxy denotes a straight-chain group containing 1 to 12 carbon atoms and the alkyl groups in the dialkylamino each denote a straight-chain alkyl group containing 1 to 4 carbon atoms are described.

Liquid crystal mixtures

Liquid crystalline mixtures comprising trans-phenyldioxane, phenylpyrimidine and phenylbenzoate compounds which are useful in electro-optical apparatuses are disclosed.

Liquid crystal mixtures having positive anisotropy of the dielectric constants comprising a nematogenic material having a clearing point above 60.degree. C., one or more compounds of the formula ##STR1## wherein R.sub.1 and R.sub.2 are hydrogen or straight-chain alkyl, provided that at least one of R.sub.1 and R.sub.2 is other than hydrogen and that R.sub.1 and R.sub.2 together contain no more than 9 carbon atoms, and, if desired, one or more additional doping agents, are described.

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Basel, Switzerland

Alfred Germann