Abstract: Compounds of the formula (I)R.sup.1 --(A.sup.1).sub.a (--M.sup.1).sub.b --(--A.sup.2).sub.c (--M.sup.2).sub.d (--A.sup.3).sub.e (--M.sup.3).sub.f (--A.sup.4).sub.g --H(I)in which the symbols and indices have the following meanings:R.sup.1 is B or a straight-chain or branched alkyl radical having 1 to 22 carbon atoms (with or without an asymmetrical carbon atom) in which, in addition, it is possible for one or two non-adjacent --CH.sub.2 -- groups to be replaced by --O--, --S--, --CO--, --CO--O--, --O--CO--, --CO--S--, --S--CO--, --O--CO--O--, --CH.dbd.CH--, --C.tbd.C--, .DELTA. or --Si(CH.sub.3).sub.2 --, and in which, in addition, one or more hydrogen atoms of the alkyl radical may be substituted by F, Cl, Br or CN, or is a chiral group, for example an epoxide, a dioxolane or a cyclic lactone,--(A.sup.1).sub.a (--M.sup.1).sub.b --(--A.sup.2).sub.c (--M.sup.2).sub.d (--A.sup.3).sub.e (--M.sup.3).sub.f (--A.sup.4).sub.

Abstract: 2-Fluoropyridines, processes for their preparation and their use in ferroelectric liquid crystal mixturesA 2-fluoropyridine of the formula (I) ##STR1## in which the symbols have the following meaning: R.sup.1, R.sup.2, independently of one another, are, for example, H or straight-chain or branched alkyl, A.sup.1, A.sup.2, A.sup.3, A.sup.4, identical or different, are, for example, 1-phenylene, pyrazine-2,5-diyl or trans-1,4-cyclohexylene, M.sup.1, M.sup.2, M.sup.3, M.sup.4, identical or different, are, for example, --O-- or --CO--O--, R.sup.3, R.sup.4, R.sup.6, R.sup.7, independently of one another, are, for example, H or straight-chain or branched alkyl, M.sup.5 is, for example, --O--CO-- or a single bond, k, l, m, n, o, p, q, r are zero or one, with the proviso that the sum of k+m+p+r is less than 4 and greater than zero, can advantageously be used as a component in ferroelectric liquid crystal mixtures.

Abstract: 2-Fluoropyrazines, process for their preparation, and their use in liquid-crystalline mixturesA 2-fluoropyrazine of the formula (I) ##STR1## in which the symbols have the following meanings: R.sup.1 and R.sup.2, independently of one another, are, for example, H or straight-chain or branched alkyl,A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are identical or different and are, for example, 1,4-phenylene orM.sup.1, M.sup.2, M.sup.3 and M.sup.4 are identical or different and are, for example, --0-- or --CO--O--,R.sup.3, R.sup.4, R.sup.6 and R.sup.7, independently of one another, are, for example, H or straight-chain or branched alkyl,M.sup.5 is, for example, --O--CO-- or a single bond,k, l, m, n, o, p, q and r are zero or one, with the condition that the sum of k+m+p+r is less than 4 and greater than zero,can advantageously be employed as a component in liquid-crystal mixtures.

Abstract: Cyclohexylphenylpyrimidines of the formula (I) ##STR1## in which R.sup.1 is straight-chain or branched, chiral or achiral alkyl or alkenyl having 2 to 16 carbon atoms, in which one or two nonadjacent --CH.sub.2 -- groups may be replaced by --0--, --S--, --CO--, --COO--, --OCO--, --Si(CH.sub.3).sub.2 -- or --C(CH.sub.3).sub.2 --, and in which one or more hydrogen atoms of the alkyl or alkenyl radical may be replaced by fluorine atoms, and in which the terminal CH.sub.3 group of the alkyl may also be replaced by ##STR2## R.sup.2 is straight-chain or branched, chiral or achiral alkyl having 1 to 10 carbon atoms,are particularly suitable components for ferroelectric liquid-crystal mixtures since they result in favorable properties, such as, for example, high contrast, when used in electrooptical switching and display devices.

Abstract: Ferroelectric liquid crystal display comprising outer substrates, electrodes, polarizer(s), ferroelectric liquid crystalline material and alignment layer(s), in which the ferroelectric liquid crystalline material has a spontaneous polarization of Ps>20 nC.cm.sup.-2 and a natural helical pitch of less than half of the cell thickness, and the alignment layer comprises at least one lipophilizing, lipophilic and/or amphiphilic compound. The liquid crystal display according to the invention exhibits a short switching time and a significantly reduced surface memory effect, and thus achieves an improved display contrast.

Abstract: Electro-optical display devices having a cell thickness of 1 to 10 .mu.m, and containing ferroelectric liquid crystalline mixture, electrodes, alignment layer(s), in which the ferroelectric liquid crystalline mixture has a spontaneous polarization of Ps>20nC.cm.sup.-2 and a natural helical pitch of less than a half of the cell thickness, and contains lipophilizing, lipophilic or amphiphilic compounds for eliminating ionic impurities, Ferroelectric liquid crystal compositions according to the invention show a significantly reduced surface memory effect and an improved display contrast.

Abstract: Chiral oxazolidinones of the formula (I) or (II) ##STR1## in which R.sup.1 is, for example, a straight-chain or branched alkyl radical having 1 to 16 carbon atoms orR.sup.2 and R.sup.3 are, for example, --H, --CH.sub.3 or phenyl,j, 1 and n are zero, 1 or 2,k and m are zero or 1,A.sup.1, A.sup.2 and A.sup.3 are, for example, phenyl or cyclohexyl,M.sup.1 and M.sup.2 are, for example, COO or CH.sub.2 O, andX is, for example, CH.sub.2 or COO,are suitable as dopes in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases having short response times. A further advantage is that the oxazolidinones induce a helix of very low pitch, so that they are also suitable for helix compensation in LC mixtures.

Abstract: Cyclohexylphenylpyrimidines of the formula (I) ##STR1## in which R.sup.1 is straight-chain or branched, chiral or achiral alkyl or alkenyl having 2 to 16 carbon atoms, in which one or two nonadjacent --CH.sub.2 -- groups may be replaced by --O--, --S--, --CO--, --COO--, --OCO--, --Si(CH.sub.3).sub.2 -- or --C(CH.sub.3).sub.2 --, and in which one or more hydrogen atoms of the alkyl or alkenyl radical may be replaced by fluorine atoms, and in which the terminal CH.sub.3 group of the alkyl may also be replaced by ##STR2## R.sup.2 is straight-chain or branched, chiral or achiral alkyl having 1 to 10 carbon atoms,are particularly suitable components for ferroelectric liquid-crystal mixtures since they result in favorable properties, such as, for example, high contrast, when used in electrooptical switching and display devices.