Abstract: Chiral 1,2-difluorobenzene derivatives are suitable as components of chiral tilted smectic liquid-crystalline phases.

Abstract: Derivatives of 2,3-Difluorobenzoic acid compounds of the formula I ##STR1## in which R.sup.1 and R.sup.2, independently of one another, are each an alkyl group having 1 to 15 C atoms, in which, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by --O--, --CO--, --CH.dbd.CH-- and/or --C.tbd.C--, andA.sup.1 and A.sup.2, independently of one another, are each 1,4-phenylene which is unsubstituted or substituted by one or two fluorine atoms, and in which, in addition, one or two CH groups may be replaced by N, or are trans1,4-cyclohexylene, or one of the two A.sup.1 and A.sup.2 groups is alternatively a single bond,are suitable as components of liquid-crystalline phases.

Abstract: Heterocyclic 1,2-difluorobenzene derivatives of the formula I ##STR1## in which R.sup.1 and R.sup.2, in each case independently of one another, are an alkyl groups (sic) having 1-15 C atoms in which, in addition, one or more CH.sub.2 groups may be replaced by a divalent radical selected from the group comprising --O--, --S--, --CO--, --O--CO--, --CO--O--, --CH.dbd.CH-- and --C.tbd.C--, where two heteroatoms are not linked directly to one another,A.sup.1 and A.sup.2, in each case independently of one another, are a 1,4-phenylene group which is unsubstituted or monosubstituted or polysubstituted by fluorine, and in which, in addition, one or two CH groups may be replaced by N, or are a 1,3,4-thiadiazole-2,5-diyl group or a trans-1,4-cyclohexylene group,m and n are each 0 or 2,o is 0 or 1, andp is 0, 1 or 2,where (o+p) is 1, 2 or 3 and, in the case where p=2, the A.sup.2 groups and n may be identical or different with the proviso that at least one of the groups A.sup.1 and A.sup.

Abstract: The invention relates to fluorophenylpyridines of the formula I: ##STR1## where R.sup.1 and R.sup.2 are substituted and unsubstituted monovalent organic radicals.

Abstract: Chiral, tilted, smectic liquid-crystal phases containing at least two liquid-crystal components and at least one chiral doping agent, at least one liquid-crystal component being a compound having the structural unit 2,3-difluoro-1,4-phenylene, are distinguished by a very low viscosity and advantageous switching times.

Abstract: The invention relates to 5-oxy-2-phenylpyridines of the formula I ##STR1## in which m and n, independently of one another, are each from 1 to 18,Q.sup.1 is --O--, trans-1,4-cyclohexylene, 1,4-phenylene or a single bond, andQ.sup.2 is --CO--, ##STR2## or a single bond, with the provisos that in the case where Q.sup.1 =Q.sup.2 =a single bond, the sum of m+n.gtoreq.11, and in the case where Q.sup.2 =CO, the radical C.sub.n H.sub.2n+1 is straight-chain, and to ferroelectric liquid-crystalline media containing these compounds.

Abstract: 2,5-Disubstituted heterocycles of the formula I ##STR1## in which R.sup.1 and R.sup.2, each independently of one another, are alkyl, alkenyl or oxaalkyl having up to 12 C atoms,L.sup.1 and L.sup.2, each independently of one another are H or F,Y is --O--, --CO--O--, --O--CO-- or a single bond,m is 1 or 2,Z is H, F, OH or alkyl having up to 5 C atoms, andQ is --O--, --O--CO--, or if Z is fluorine or hydroxyl, is also be a single bondare suitable as components of ferroelectric mixtures.

Abstract: The invention relates to a liquid-crystalline medium for electrooptical display elements based on the ECB effect, containing two components A and B which themselves comprise one or more individual compounds, component A having clearly negative dielectric anistropy and giving the liquid-crystalline phase a dielectric anistrophy of .ltoreq.-0.3, and component B having pronounced nematogeneity and a viscosity of not more than 30 mPa.s at 20.degree. C.

Abstract: The invenion relates to a display element based on the electroclinic effect containing a liquid crystal medium being a mixture of at least two chiral components and at least one non-chiral component, characterized in that said medium has a pitch compensated cholesteric phase above the optically active smectic A phase.

Abstract: Optically active nitrogen-containing heterocycles of the formula I according to claim 1 are suitable as components for ferroelectric liquid crystalline materials.

Abstract: Optically active compounds of the formula I can be used as components of chiral titled smectic liquid crystal phases:R.sup.1 --C*HX--Q--A.sup.4 --Z.sup.1 --A.sup.2 --(Z.sup.2 --A.sup.3).sub.n --X'--Q'--C*HY'--R.sup.5 (I)whereinR.sup.1 --C*HX--Q-- and --X'--Q'--C*HY--R.sup.5 are identical optically active radicals selected from the group --O--C*HCH.sub.3 --COO--n--alkyl, --O--C*HCH.sub.3 --CH.sub.2 --O--n--alkyl, --OCO--C*HC1--CHCH.sub.3 --CH.sub.3, --OCO--C*HCl--C*HCH.sub.3 --C.sub.2 H.sub.5, --OCO--C*HCl--CH.sub.2 --CHCH.sub.3 --CH.sub.3, --OCO--C*HCl--C(CH.sub.3).sub.3, --COO--C*HCH.sub.3 -COO--n--alkyl, --O--CO--C*HCH.sub.3 --o--n--alkyl, --OCH.sub.2 --C*HCH.sub.3 --O--n--alkyl, --COO--C*HCH.sub.3 CH.sub.2 --O--n--allyl, --OC*HCH.sub.3 --CH.sub.2 --COO--n--alkyl, --COO--C*HCH.sub.3 --CH.sub.2 --COO--n--alkyl, --OCH.sub.2 --C*HCH.sub.3 --COO--n--alkyl or --COO--CH.sub.2 --C*HCH.sub.3 --COO--n--alkyl, alkyl is of 1--12 c atoms,and --A.sup.4 --Z.sup.1 --A.sup.2 --(Z.sup.2 --A.sup.3).sub.

Abstract: Compounds of the formula IR.sup.1 -A.sup.1 -A.sup.2 -R.sup.2 IwhereinR.sup.1 and R.sup.2 are each alkyl with 1-15 C atoms, and wherein one or two non-adjacent CH.sub.2 groups can also be replaced by --O--, --S--, --CO--, --O--CO--, --CO--O--, --CO--S--, --S--CO--, --CHHalogen--, --CHCN-- and/or --CH.dbd.CH--,A.sup.1 is 1,4-phenylene, trans-1,4-cyclohexylene or a single bond andA.sup.2 is ##STR1## in which Z is --O--CO--, --CO--O--, --S--CO--, --CO--S--, CH.sub.2 O--, --OCH.sub.2 -- or --CH.sub.2 CH.sub.2 --, with the proviso that, if A.sup.1 is a single bond, A.sup.2 is ##STR2## are suitable as components of chirally tilted smectic liquid crystal phases.

Abstract: 2,3-Difluorophenol derivatives of the formula ##STR1## wherein R.sup.1 and R.sup.2, in each case independently of one another, are an alkyl group having 1 to 15 C atoms in which, in addition, one or two nonadjacent CH.sub.2 groups may be replaced by --O--, --CO--, --CH.dbd.CH-- and/or --C.tbd.C--;A is 1,4-phenylene which is unsubstituted or substituted by one or two fluorines, or is trans-1,4-cyclohexylene or a single bond; andL.sup.1 and L.sup.2, in each case independently of one another, are H or F,are suitable as components of liquid-crystalline media.

Abstract: The invention relates to the use of compounds of the formula IR.sup.1 --Q.sup.1 --A--(A.sup.2).sub.q --R.sup.2 Iwherein ##STR1## and R.sup.1, R.sup.2, Q.sup.1, Q.sup.2 and q have the meaning specified in claim 1, as components of smectic liquid-crystalline phases, and also smectic liquid-crystalline phases, in particular chiral tilted smectic phases containing compounds of formula I.

Abstract: The invention relates to the use of trifluorotoluene derivatives of the formula I ##STR1## in which R.sup.1 is alkyl having 1 to 12 carbon atoms in which, in addition, one or more non-neighboring CH.sub.2 groups may be replaced by --O--, --CO--, --O--CO--, --CO--O--, --O--CO--O--, --CH-halogen, --CH--CN-and/or --CH=CH--,A.sup.1 and A.sup.2, in each case independently of one another, are 1,4-phenylene in which, in addition, one or more CH groups may be replaced by N, trans-1,4-cyclohexylene in which, in addition, one or two non-neighboring CH.sub.2 groups may be replaced by --O--and/or --S--, or 1,4-bicyclo(2,2,2)octylene, each of which is unsubstituted or monosubstituted or poly-substituted by halogen, nitrile and/or CH.sub.3,Z.sup.1 and Z.sup.2, in each case independently of one another, are --CO--O--, --O--CO--, --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 -- or a single bond, andn is 0 or 1,as components of chiral tilted smectic phases.

Abstract: Compounds of the formula I ##STR1## wherein R.sup.1 and R.sup.2 each independently of one another are R, OR, OCOR, COOR or OCOOR,is alkyl with 1 to 15 C atoms, wherein one or more CH.sub.2 groups which are not adjacent and are not linked by O can also be replaced by --O--, --CO--, --O--CO--, --CO--O--, --CH--halogen, --CHCN-- and/or --CH.dbd.CH--,A.sup.1, A.sup.2 and A.sup.3 each independently of one another are 1,4-phenylene or trans-1,4-cyclohexylene,m, n and o are each 0 or 1,m+n+o is 0, 1 or 2,Z.sup.1 and Z.sup.2 each independently of one another are --CH.sub.2 --O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 -- or a single bond andX is F, Cl, Br, I or CN,with the provisos given in claim 1, can be used as components of ferroelectric liquid crystal phases.

Abstract: Optically active nitrogen-containing heterocycles of the formula I according to claim 1 are suitable as components for ferroelectric liquid crystalline materials.