DD254589A5 - CHIRAL-TREATED SMEKTIC LIQUID CRYSTALLINE PHASE - Google Patents

Abstract

The present invention relates to a chiral tilted smectic liquid-crystalline phase having at least two liquid-crystalline components, characterized in that they contain at least one optically active compound of the formula R 1 -C-HX-Q-A4-Z1-A2- (Z 2-A3) n XQ -CHY -R5enthaelt. With the provision of the compounds of the formula I, the range of liquid-crystalline substances which are suitable for producing ferroelectric mixtures under various aspects of application technology is also very broadly broadened.

Description

Field of application of the invention

The invention relates to a chiral tilted smectic liquid-crystalline phase having at least two liquid-crystalline components, characterized in that it contains at least one optically active compound of the formula I.

R ¹ -C * HX-QA ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -X'-Q'-C * HY'-R ⁵

R ^{1 is} an alkyl or perfluoroalkyl group each having 1-12 C atoms, wherein also one or _two non-adjacent CH ₂ -

or CF ₂ groups which contain O atoms and / or CO groups and / or CO-O groups and / or -CH =CH groups and / or -CHHalogen and / or -CHCN groups and / or -O-CO-CH-halo and / or -O-CO-CHCN groups may be replaced,

R ^{5 is} an alkyl group other than Y 'having 1 to 15 C atoms, wherein also one or two non-adjacent

CH ₂ groups can be replaced by -O-, -CO-, -O-CO-, -CO-O- and / or -CH =CH-,

A ² , A ^{3 are} each unsubstituted or by a or

and A ^{4 is} 1,4-phenylene which is substituted by two F and / or Cl atoms and / or CH ₃ groups and / or CN groups, in which also one or two CH groups may be replaced by N, 1,4-cyclohexylene in which also one or two non-adjacent CH ₂ groups can be replaced by O atoms and / or S atoms, piperidine-1 -diyU-bicyclo- (2,2,2) -octylene-, naphthalene-2 , 6-diyl, decahydronaphthalene-2,6-diyl-oder1,2,3,4-tetrahydronaphthalene-2,6-diyl groups,

Z ¹ and Z ² each are -CO-O -, -O-, -, - CH ₂ CH ₂ -, - OCH ₂ -, - CH ₂ O -, - C = C- or a single bond,

X is halogen, CN or CH ₃ ,

η O or. 1,

Q is alkylene having 1 to 4C atoms, in which also a CH ₂ group is represented by -O-, -CO-, -O-C0 -, -CO-O-, -CH = CH-COO-,

- CH = CH -, - I can replace halogeruind or CHCN, or a single bond

X 'is -CO-O- -O-CO-Z-CMCO-O-, -έΟ-, -Ο-, -S-, T-CH =CH-, HH =CH ^ OO-or a single bond, "

Q 'alkylene having 1 to 5 C atoms, in which also a non-linked with X' CH ₂ group by -0 -, - CO -, - 0-CO, -CO-O-

or -CH = CH-, or a single bond, and

Y 'is CH, halo, methyl or methoxy

with the proviso that R ¹ and / or R ^{5 is} a branched alkyl group having 3 to 12 C atoms, if -C * HX-O-CH-halo-CO-O- and / or -X'-Q'- C * HY'-0-CO-CHHalogen means contains.

Characteristic of the known technical solutions

Like similar compounds described in DE-OS 3515373, the compounds of the formula I can be used as components of chiral tilted smectic liquid-crystalline phases.

Chiral touted smectic liquid crystal phases with ferroelectric properties can be prepared by blending base mixtures with one or more tinted smectic phases with a suitable chiral dopant (L A. Beresnev et al., Mol. Cryst. Liq. Cryst. 89, 327 [1982 HR Brand et al., J. Physique 44, [lett], L-771 [1983]). Such phases can be used as dielectrics for fast switching displays based on the principle of SSFLC technology described by Clark and Lagerwall (Naclark and ST Lagerwall, Appl. Phys. Lett., 36, 899 [1980], USP 4,367,924) based on the ferroelectric properties of the chiral tilted phase are based. In this phase, the elongated molecules are arranged in layers, the molecules having a tilt angle to the layer normal. As layer to layer progresses, the tilting direction changes by a small angle with respect to an axis perpendicular to the layers so that a helix structure is formed. In displays based on the principle of SSFLC technology, the smectic layers are arranged perpendicular to the plates of the cell. The helical arrangement of the valve directions of the molecules is suppressed by a very small distance of the plates (about 1-2μηι). This forces the longitudinal axes of the molecules to align in a plane parallel to the plates of the cell, giving rise to two excellent tilt orientations. By applying a suitable alternating electric field, it is possible to switch back and forth between these two states in the liquid-crystalline phase having a spontaneous polarization. This switching process is much faster than conventional twisted-cell (TN-LCD) based on nematic liquid crystals. A major drawback to many applications of currently available materials with chiral tutted smectic phases (such as Sc *) is their relatively high optical anisotropy, insufficient short switching times due to relatively high viscosity values, and dielectric anisotropy values greater than zero or if negative, only slightly different from zero values. Negative values of dielectric anisotropy are required if the required planar orientation is effected by superposition of the drive field with a small amplitude AC holding field (J. M. Geary, SID Meeting, Orlando / Florida, April / May 1985, Lecture 8.3).

Object of the invention

The invention had the object of finding new compounds which are suitable as components of such phases.

Explanation of the essence of the invention

It has now been found that the use of compounds of the formula I as components of chiral tilted smectic mixtures can substantially reduce the disadvantages mentioned. The compounds of formula I are thus excellently suitable as components of chiral tilted smectic liquid crystalline phases. In particular, they are chemically particularly stable chiral tilted smectic liquid-crystalline phases with favorable ferroelectric phase ranges, in particular with broad Sc * phase ranges, negative or positive dielectric anisotropy, low optical anisotropy, favorable pitch height and for such phases high values for the spontaneous polarization and very short switching times can be produced. P is the spontaneous polarization in nC / cm ² .

In addition, with the provision of the compounds of the formula I, the range of liquid-crystalline substances which are suitable for the production of ferroelectric mixtures from a variety of application-technical points of view is considerably widened considerably. The compounds of the formula I have a wide range of applications. In dependence of

the choice of substituents, these compounds can serve as base materials, of which liquid-crystalline phases are composed for the most part; However, it is also possible to add compounds of the formula I to liquid-crystalline base materials from other classes of compounds, for example the dielectric and / or optical anisotropy and / or the spontaneous polarization and / or the phase range and / or the tilt angle and / or the pitch and / or the Switching times of such a phase vary. The compounds of the formula I are furthermore suitable as intermediates for the preparation of other substances which can be used as constituents of liquid-crystalline phases.

The compounds of the formula I are colorless in the pure state and have low values of optical anisotropy.

Some of the compounds of the formula I show liquid-crystalline mesophases in a temperature range which is favorably located for the electro-optical use, but it is also possible to use isotropic or monotropic liquid-crystalline compounds of the formula I as components of chirally tilted smectic phases. Chemically, thermally and against light, they are very stable.

The invention thus relates to the use of the compounds of the formula I as a component of liquid-crystalline phases.

The invention also relates to chiral tilted smectic liquid-crystalline phases containing at least one optically active compound of the formula I. The invention furthermore relates to liquid-crystal display elements, in particular electro-optical display elements, which contain such phases.

For the sake of simplicity, in the following, Ph represents a 1,4-phenyl group in which also one or two CH groups may be replaced by N, Cy a 1 ^ cyclohexylene group, wherein also one or two non-adjacent CH ₂ groups are represented by O atoms and Bi may be a bicyclo (2,2,2) octylene group.

Above and below, R ¹ , R ⁵ , n. A ² , A ³ , A ⁴ , Q, X, X ', Q', Y ', Z ¹ and Z ^{2 have} the stated meaning, unless expressly stated otherwise is.

The compounds of the formula I accordingly comprise, in particular, compounds of the partial formulas Ia and Ib (with two rings)

R ¹ -C * HX-QA ⁴ -A ² -X'-Q'-C * HY'-R ⁵ la

R ¹ -C * CX-OA ⁴ -Z ¹ -A ² -X'-Q'-C * HY'-R ⁵ Ib

and Ic to If (with three rings):

R ¹ -C * HX-QA ⁴ -A ² -A ³ -X'-Q'-C * HY'-R ⁵ Ic

Ρ ^Ί -ΰ * ΗΧ-α-Α ⁴ -Α ² -Ζ ² -Α ³ -Χ'-α'-ΰ * ΗΥ'-Ρ ⁵ Id

R ¹ -C * HX-QA ⁴ -Z ¹ -A ² -A ³ -X'-Q'-C * HY'-R ⁵ Ie

R ¹ -C * HX-QA ⁴ -Z ¹ -A ² -Z ² -A ³ -X'-Q'-C * HY'-R ⁵ If

Of these, those of the formulas Ia, Ib, Ic, Id and Ie are particularly preferred.

The preferred compounds of the formula Ia include those of the partial formulas Ia to Ia 4:

R ¹ -C * HX-Q-Ph-Ph-X'-Q'-C * HY'-R ⁶ la 1

R ¹ -C * HX-Q-Cy-Ph-X'-Q'-C * HY'-R ⁵ la 2

R ¹ -C * HX-Q-Ph-Cy-X'-Q'-C * HY'-R ^s la 3

R ¹ -C * HX-a-Cy-Cy-X'-Q'-C * HY'-R ^s la 4

Of these, those of the formulas Ia and Ia3 are particularly preferred.

The preferred compounds of the formula Ib include those of the partial formulas Ib 1 to Ib 4:

R ¹ -C * HX-Q-Ph-Z ¹ -Ph-X'-a'-C * HY'-R ^s Ib 1

R ¹ -C * HX-Q-Cy-Z ¹ -Ph-X'-Q'-C * HY'-R ⁵ Ib 2

R ¹ -C * HX-Q-Ph-Z ¹ -Cy-X'-Q'-C * HY'-R ⁵ Ib 3

R ¹ -C * HX-Q-Cy-Z ¹ -Cy-X'-Q'-C * HY'-R ⁵ Ib 4

Of these, those of the formulas Ib 1 and Ib 3 are particularly preferred.

The preferred compounds of the formula Ic include those of the subformulae Id to Ic4:

R ¹ -C * HX'-Q-Ph-Ph-Cy-X'-Q'-C * HY'-R ^s Id

R ¹ -C * HX-Q-Ph-Cy-Cy-X'-Q'-C * HY'-R ⁶ Ic 2

R ¹ -C * HX-Q-Ph-Cy-Ph-X'-Q'-C * HY'-R ⁵ Ic 3

R ¹ -C * HX-Q-Ph-Ph-Ph-X'-Q'-C * HY'-R ₅ Ic 4

The preferred compounds of the formula Id include those of the subformulae Id 1 to Id 3:

R ¹ -C * HX-Q-Ph-Ph-Z ² -C y -X'-Q'-C * HY'-R ⁵ Id 1

R ¹ -C * HX-Q-Ph-Cy-Z ² -Ph-X'-Q'-C * HY'-R ⁵ Id 2

R'-C ^ HX-Q-Ph-PhZ-Ph-X'-Q'-C ^ Y'-R ⁵ Id 3

The preferred compounds of the formula Ie include those of the partial formulas Ie 1 to Ie 5:

Ri_Qi_C * HX-Q ² -Ph-Z ¹ -Ph-Ph-X'-O-C * HY'-R ⁵ Ie 1

Ri_Qi_C * HX-Q ² -Ph-Z ¹ -Ph-Cy-X'-Q'-C * HY'-R ⁵ Ie 2

Ri_Qi_C * HX-Q ² -Ph-Z ¹ -Cy-Ph-X'-Q'-C * HY'-R ⁵ Ie 3

Ri_Qi_C * HX-Q ² -Ph-Z ¹ -Cy-Cy-X'-Q'-C * HY'-R ⁵ Ie 4

Ri_Qi_c * HX-Q ² -Cy-Z ¹ -Ph-Ph-X'-Q'-C * HY'-R ⁵ Ie 5

Preference is given to compounds of the formulas above and below in which R ¹ and R ^{5 are} each independently of the other alkyl.

In the preferred compounds of the formulas above and below, the alkyl radicals in which a CH ₂ group (alkoxy or oxaalkyl) may also be replaced by an O atom may be straight-chain or branched. Preferably, they have 5,6,7,8,9 or 10 carbon atoms and therefore preferably pentyl, hexyl, heptyl, octyl, nonyl, decyl, pentoxy, hexoxy, heptoxy, octoxy, nonoxy or decoxy, and also ethyl, propyl , Butyl, undecyl, dodecyl, propoxy, ethoxy, butoxy, undecoxy, dodecoxy, 2-oxapropyl (= 2-methoxymethyl), 2 - (= ethoxymethyl) or 3-oxabutyl (= 2-methoxypentyl), 2, 3 or 4 Oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl.

A ² , A ³ and A ⁴ are preferably Cy or Ph. In the compounds of the formulas above and below, Ph is preferably a 1,4-phenylene- (Phe), a pyrimidine-2,5-diyl- (Pyr), a pyridine-2,5-diyl- (Pyn), a pyrazine-3,6-diyl or a pyridazine-2,5-diyl group, more preferably Phe, Pyr or Pyn. Preferably, the compounds of the invention contain no more than one 1,4-phenylene group wherein one or two CH groups are replaced by N. Cy is preferably a 1 ^ cyclohexylene group. However, particular preference is given to compounds of the formula I in which one of the groups A ² , A ³ and A ^{4 is a} 1,4-cyclohexylene group substituted by CN in a 1- or 4-position and the nitrile group is in the axial position, ie the group A ² , A ³ or A ^{4 has} the following configuration:

Particularly preferred are compounds of the formula I and the preceding sub-formulas which contain a -Ph-Ph grouping. -Ph-Ph- is preferably -Phe-Phe-, Phe-Pyr or Phe-Pyn. Particularly preferred are the groups

© &" ^and '© - ©'

such as

furthermore unsubstituted or mono- or polysubstituted by fluorine 4,4-biphenylyl.

Z ¹ and Z ² are preferably single bonds, secondarily preferably -O-CO-, -CO-O, -C = C or -CH ₂ CH ₂ groups.

Particularly preferred for Z ¹ is -CO-O-, -0-C0-, -C = C- or -CH ₂ CH ₂ -, in particular the -CH ₂ CH ₂ - and the -C = C group.

X in the compounds of the formulas above and below denotes halogen, CN or CH ₃ , preferably Cl or CH ₃ .

The preferred meaning of QistAlkylen with 1 to 2 C-atoms-0 -, - 0-CO and -COO-.

Compounds of the formulas above and below with branched groups R ¹ or R ⁵ may be of importance.

Branched groups of this kind usually contain no more than two chain branches. R ¹ or R ⁵ is preferably a straight-chain group or a branched group with not more than one chain branch. Preferred branched radicals are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), tert-butyl, 2-methylbutyl, isopentyl (= 3-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2 Ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 1-methylheptoxy, 2-oxa-3-methylbutyl , S-oxa-methylpentyl.

X 'is preferably -CO-O-, -O-CO-, -CH = CH-COO- (trans) or a single bond. Particularly preferred are -CO-O-, -O-CO- or a single bond.

Q 'is _{preferably-CH2} -, - CH ₂ CH 2 -, - CH ₂ CH 2 CH ₂ -odereine single bond, particularly preferably a single bond. Y 'is preferably CH ₃ , -CN or Cl, most preferably Cl or CH ₃ .

R ⁵ is preferably straight-chain or branched alkyl having 1 to 10, in particular to 7, carbon atoms. Among the compounds of the formula I, preference is given to those in which X and Y 'are not simultaneously methyl. Among the compounds of the formula I and la to Iq, preference is given to those in which at least one of the radicals contained therein has one of the preferred meanings given.

A small group of particularly preferred meanings for the optically active radicals R ¹ (or R ¹ -C * HX-Q) and -X'-Q'-C * HY'-R ⁶ in these preferred compounds is given below:

-OC * HCH ₃ -n-alkyl, -O-CH ₂ -C * HCH ₃ -n-alkyl, -O-CH ₂ -CH ₂ -C * HCH ₃ -n-AII <yl, -O-CH ₂ -CH ₂ -CH ₂ -C * HCH ₃ -n-alkyl, -CHCHy-n-alkyl, -CH _2- C * HCH ₃ -n-alkyl, -COO-C * CHCHr-n-alkyl, -COO-CHz- C ^ CHa-n-alkyl, -O-C * HCH3-COQ-n-alkyl, -O-C * HCH ₃ -CHZ-On-alkyl, -OCO-C ^ CI-CHCH ₃ -CH _3, -OCO-C * HCI -C * HCH 3 -C ₂ H ₅ , -OCO-C ¹ HCl-CH ₂ -CHCH ₃ -CH ₃ , -OCO-C * HCI-C (CH ₃ ) ₃ , -COO-C * HCH ₃ -COO -N-alkyl, -O-CO-C * HCH ₃ -On-alkyl, -OCHz-C ^ CHr-on-alkyl, -COO-C * HCH ₃ -CH ₂ -On-alkyl, -OC * HCHr- CHr-COO-n-alkyl, -COO-C * HCH ₃ -CH 2 COO-n-alkyl, -OCH ₂ -C * HCH ₃ -COO-n-alkyl, -COO-CH ₂ -C-COO * HCH3 n-alkyl.

In the preferred compounds of formula I wherein -X'-Q'-C * HY'-R ^{5 is} an optically active group, Ρ ^Ί -Ο * ΗΧ -Q may be the same or different than -X'-O-C Be HY'-R ⁵ .

Preferably, -X'-Q'-C * HY'-R ⁵ and R ¹ -C * HX-Q are different and have a preferred meaning given for -X'-Q'-C * HY'-R ⁵ . ,

A small group of particularly preferred compounds of formula 11 to 123 is listed below: CH ₃ -CHCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OOC-C * HCI-CHCH ₃ -CH ₃ Π

C ₂ H ₅ -C * HCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OOC-C * HCI-C * HCH ₃ -C ₂ H ₆ 12

CH ₃ -CHCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OC * HCH ₃ -COO-C ₂ H ₅ I ₃

CH ₃ -CHCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OC * HCH ₃ -CH ₂ -OC ₂ H ₅ I4

CH ₃ -CHCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OC * HCH ³ -CH ₂ -COO-C ₂ H ₅ I5

C ₂ H ₅ -C * HCH ₃ -C * HCI-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OCH ₂ -C * HCH ₃ -COO-C ₃ H ₇ I6

CH ₃ -CHCH ₃ -C * fHCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OCH ₂ -C * HCH ₃ -C ₂ H ₅ I7

C ₂ H 1 C * HCH ₃ C * HCI-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OC * HCH ₃ -C ₆ H ₁₃ I8

C ₂ H5-C * HCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -C * HCH ₃ -C ₆ H ₁₃ 3I9

CH ₃ -CHCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -COO-C * HCH ₃ -COO-H ₂ H ₅ 110

C ₂ H 5 -C * HCH ₃ -C * HCI-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -COO-CH ₂ -C * HCH ₃ -COO-C ₃ H ₇ 111

C ₂ H5-C * C * HCH3-HCI-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³⁾ _n -OCH ₂ -C * HCH3-OC ₂ H ₅ CH ₃ -CHCH3-C * HCI-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -COO-C * HCH ³ -CH ₂ -COO-C ₄ H ₉ C ₂ H 5 -C * HCH 3 -C * HCl-COO -A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _r -OCO-C * HCI-tC ₄ H ₉ C ₂ H _s -C * HCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OOC-C * HCl-iC ₄ H ₉ C ₂ H 5-C * HCH 3 -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² - A ³ ) _n -OC * HCH ³ COO-C ₂ H 5 CH ₃ -CHCH ₃ -C * HCl-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OCH ₂ -C * HCH ₃ -C ₂ H5

C3H7-OOC-C * HCH3-OA ⁴ -Z ¹ -A ² - (Z ² -A ³⁾ _n -OC * HCH3 C3H7-COO-C ₃ H7-O-CH ₂ -C * HCH3-OA ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -OC * HCH _y -CH ₂ OC ₃ H ₇ C ₂ H _s -OOC-C * HCH 3 -OOC-A ⁴ -Z ¹ -A ² - (Z ² -A ³⁾ _n -COO-C * CHCH3-COO-C ₂ H 5 C ₂ H5 OC * HCH3-COO-A ⁴ -Z ¹ -A ² - (Z ² -A ³⁾ _n -OOC-C * HCH ₃ -0-C ₂ H ₅ C ₂ H ₅ -OC * HCH 3 -CH ₂ -OA ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -O-CH ₂ -C * HCH ³ -O-C ₂ H ₅ 112 113 114 115 116 117 118 119 I20 121 122 I23

Particularly preferred are optically active compounds of the formula I, characterized by the formulas

R ¹ -C * HX-COO-A ⁴ -Z ¹ -A ² - (2 ² -A ³ ) _n -OOC-C * HY'-R ⁵ and

R ¹ -C * HX-COO-A ⁴ -Z ¹ -A ² -OOC-C * HY'-R ⁵

wherein R ¹ , R ⁵ , n, X, Y ', A ² , A ³ , A ⁴ , Z ¹ and Z ^{2 have} the meaning given in claim 1.

Particularly preferred are compounds of the above formulas wherein X and Y 'are halogen, compounds of the above

Formulas in which A ⁴ and A ^{2 are} 1,4-phenylene, and corresponding compounds wherein Z ^{1 is} a single bond.

In the compounds of formula I and in the preceding and following sub-formulas, -A ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _{n is} preferably one

Group of the following formulas 1 to 16 or their mirror image:

"0-0-

(p = 1, 2, 3, or 4, q = 0, 1, 2, 3, or 4)

-0-0-0-

^s -0-

N O>

- ( O> -C00- (O) -

11

12

14

- / o Vc = c-

-0-CO.0-0-

15

Groups of the formulas 1,5,7,9,10,11,12,13 and 14, especially those of the formulas 5 and 7, are particularly preferred.

Those of the abovementioned formulas which contain one or more groups Dio, Dit, Pip and / or Pyr each include the two possible 2,5- (Dio, Dit, Pyr) or 1,4-position isomers (Pip).

The compounds of the formula are prepared by methods known per se, as described in the literature (for example in the standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg Thieme Verlag, Stuttgart) under reaction conditions which are known and suitable for the said reactions. One can also make use of known per se, not mentioned here variants.

If desired, the starting materials can also be formed in situ, such that they are not isolated from the reaction mixture, but immediately reacted further to give the compounds of the formula I.

Thus, the compounds of formula I can be prepared by reducing a compound otherwise conforming to formula I but containing one or more reducible groups and / or C-C bonds instead of Η-atoms.

As reducible groups are preferably -CH = CH groups into consideration, further z. B. free or esterified hydroxy groups, aromatically bonded halogen atoms or carbonyl groups. Preferred starting materials for the reduction correspond to the formula I, but instead of a -CH ₂ CH ₂ group, they may be a -CH = CH group and / or a -CO ₂ group instead of a -CH ₂ group and / or instead of a -CH ₂ group Η atoms contain a free or a functional (eg in the form of their p-toluenesulfonate) modified OH group.

The reduction can z. Example, by catalytic hydrogenation at temperatures between about 0 ° and about 200 ° and pressures between about 1 and 200 bar in an inert solvent ^. An alcohol such as methanol, ethanol or isopropanol, an ether such as tetrahydrofuran (THF) or dioxane, an ester such as ethyl acetate, a carboxylic acid per acetic acid or a hydrocarbon such as cyclohexane. Suitable catalysts are suitably noble metals, ie Pt or Pd, which are used in the form of oxides (for example PtO ₂ , PdO), on a support (for example Pd on carbon, calcium carbonate or strontium carbonate) or in finely divided form can.

Ketones may also be prepared by the methods of Clemmensen (with zinc, amalgamated zinc or tin and hydrochloric acid, suitably in aqueous-alcoholic solution or in heterogeneous phase with water / toluene at temperatures between about 80 and 120 ° C) or Wolff-Kishner (with hydrazine, conveniently in Presence of alkali such as KOH or NaOH in a high boiling solvent such as diethylene glycol or triethylene glycol at temperatures between about 100 and 200 °) to the corresponding compounds of formula I containing alkyl groups and / or -CH ₂ CH ₂ bridges.

Furthermore, reduction with complex hydrides are possible. For example, arylsulfonyloxy groups can be removed by reduction with LiAlH ₄ , in particular p-toluenesulfonyloxymethyl groups can be reduced in methyl groups, expediently in an inert solvent such as diethyl ether or THF at temperatures between about 0.degree. C. and 100.degree. Double bonds can be hydrogenated (also in the presence of CN groups!) With NaBH ₄ or tributyltin hydride in methanol; so arise z. B. from 1-Cyancyclohexenderivaten the corresponding Cyclohexanderivate.

Esters of formula I can also be obtained by esterification of corresponding carboxylic acids (or their reactive derivatives) with alcohols or phenols (or their reactive derivatives).

Particularly suitable as reactive derivatives of said carboxylic acids are the acid halides, especially the chlorides and bromides, and also the anhydrides, eg. As well as mixed anhydrides, azides or esters, especially alkyl esters with 1-4 carbon atoms in the alkyl group.

Suitable reactive derivatives of said alcohols or phenols are, in particular, the corresponding metal alcoholates or phenolates, preferably an alkali metal such as Na or K.

The esterification is advantageously carried out in the presence of an inert solvent. Particularly suitable are in particular ethers such as diethyl ether, di-n-butyl ether, THF, dioxane or anisole, ketones such as acetone, butanone or cyclohexanone, amides such as DMF or phosphoric hexamethyltriamide, hydrocarbons such as benzene, toluene or xylenol, halogenated hydrocarbons such as carbon tetrachloride or tetrachlorethylene and sulfoxides such Dimethyl sulfoxide or sulfolane. Water-immiscible solvents can be advantageously used simultaneously to azeotropically distill off the water formed in the esterification. Occasionally, an excess of an organic base, e.g. Pyridine, quinoline or triethylamine can be used as a solvent for the esterification. The esterification may also be carried out in the absence of a solvent, e.g.

by simply heating the components in the presence of sodium acetate. The reaction temperature is usually between -50 ° C and +250 ⁰ C, preferably between -20 ° C and +80 ⁰ C. At these temperatures, the esterification reactions are generally complete after 15 minutes to 48 hours.

In particular, the reaction conditions for the esterification depend largely on the nature of the starting materials used. Thus, a free carboxylic acid is usually reacted with a free alcohol or phenol in the presence of a strong acid, for example a mineral acid ₍ such as hydrochloric acid or sulfuric acid.) A preferred reaction is the reaction of an acid anhydride or, especially, an acid chloride with an alcohol, preferably in one basic medium, important bases being, in particular alkali metal hydroxides, such as sodium or potassium hydroxide, alkali metal carbonates or hydrogen carbonates such as sodium carbonate ^, potassium carbonate or potassium hydrogen carbonate, alkali metal acetates such as sodium or potassium acetate _f, alkaline earth metal hydroxides such as calcium hydroxide or organic bases _f as triethylamine, pyridine, lutidine, collidine Another preferred embodiment of the esterification is that the alcohol or phenol is first converted into the sodium or potassium alcoholate or phenolate, for example by treatment with ethanolic sodium hydroxide the potassium hydroxide solution, this isolated and suspended together with sodium bicarbonate or potassium carbonate with stirring in acetone or diethyl ether and this suspension with a solution of the acid chloride or anhydride in diethyl ether, acetone or DMF, preferably at temperatures between about -25 ° C and + 2O ⁰ C. Dioxane derivatives or dithiane derivatives of the formula I are advantageously prepared by reacting a corresponding aldehyde (or one of its reactive derivatives) with a corresponding 1,3-diol or a corresponding 1,3-dithiol (or one of its reactive derivatives), preferably in Presence of an inert solvent _# such as benzene or toluene and / or a catalyst, e.g. As a strong acid such as sulfuric acid, benzene or p-toluenesulfonic acid, at temperatures between 20 ⁰ C and about 150 ⁰ C, preferably between 80 ⁰ C and 120 ⁰ CAIs reactive derivatives of the starting materials are primarily acetals.

The mentioned aldehydes and 1,3-diols or 1,3-dithiols and their reactive derivatives are known in some cases, all of which can be prepared without difficulty by standard methods of organic chemistry from compounds known from the literature. For example, the aldehydes are obtainable by oxidation of corresponding alcohols or by reduction of corresponding carboxylic acids or their derivatives, the diols by reduction of corresponding diesters and the dithiols by reacting corresponding dihalides with NaSH.

For the preparation of nitriles of the formula I, corresponding acid amides, for. For example, those in which instead of the radical X is a CONH ₂ group are dehydrated. The amides are z. B. from corresponding esters or acid halides by reaction with ammonia available. Dehydrating agents are, for example, inorganic acid chlorides such as SOCl _2, PCl _3, PCI ₅ POCl _3, SO ₂ Cl _2, COCl _2, further P ₂ O ₆ P ₂ S _5, AICI ₃ (z. B. as a double compounds are suitable, with NaCl), aromatic sulfonic acids and sulfonic acid halides. You can work in the presence or absence of an inert solvent at temperatures between about OX and 150 ⁰ C; suitable solvents are, for example, bases such as pyridine or triethylamine, aromatic hydrocarbons such as benzene, toluene or xylene or amides ₍ such as DMF). For the preparation of the abovementioned nitriles of the formula I it is also possible to react corresponding acid halides, preferably the chlorides, with sulfamide , expediently in an inert solvent such as tetramethylenesulphone at temperatures between about 80 ^° C. and 150 ^° C., preferably at 120 ^° C. After customary work-up, the nitriles can be isolated directly Ethers of the formula I are obtained by etherification of corresponding hydroxy compounds, preferably corresponding phenols The hydroxy compound is advantageously first converted into the corresponding metal derivative, eg by treatment with NaH, NaNH ₂ , NaOH, KOH, Na ₂ CO ₃ or K ₂ CO ₃ in the corresponding alkali metal alcoholate or alkali metal phenolate with the appropriate alkyl halide, sulfonate or dialkyl sulfate are reacted, expediently in an inert solvent such as acetone, 1,2-dimethoxyethane, DMF or dimethyl sulfoxide or an excess of aqueous or aqueous-alcoholic NaOH or KOH at temperatures between about 2O ⁰ C and 100 ⁰ C. For the preparation of nitriles of Formula I can also be reacted with a corresponding cyanide corresponding chlorine or bromine compounds of formula I, expediently with a metal cyanide such as NaCN, KCN or Cu ₂ (CN) ₂ , for example in the presence of pyridine in an inert Lösungsmitteh / vie DMF or N-methylpyrrolidone at temperatures between 2O ⁰ C and 200 ⁰ C. The optically active compounds of formula I is obtained by the use of appropriate optically active starting materials and / or by separation of the optical antipodes by chromatography according to known methods.

The phases according to the invention contain at least one, preferably at least two compounds of the formula I. Particular preference is given to chiral tilted smectic liquid-crystalline phases according to the invention whose achiral base mixture contains, in addition to compounds of the formula I, at least one other component with a negative or absolute small positive dielectric anisotropy. These further component (s) of the chiral base mixture may constitute 1 to 50%, preferably 10 to 25%, of the base mixture. Compounds of the subformulae Va to Vp are suitable as further components with an amount of small positive or negative dielectric anisotropy:

R ⁴

- / θ \ -COX "- / o \ -R ⁵ Va

(F) n

COX "- (0) -R ⁵ Vb

R - < H fc-COX "- ^ H

Vc

(F) n

R ⁴ - / 0 V- / o \ -COX "- / o \ -R ^E

R ⁴ - / oV / ο \ -οοχ "- / μ Vr ^e

R ⁴ - / θ \ -COX "- / oV / o \ -R ^E

R - <H P COO

vd

Ve

Vf

Vg

Vh

R ⁴ - / H - / H V-COO- / H V-

vi

vj

(F) n

vk

(F) n

-R Vl

^L dI-0- ° ^c v0- * Vm

(F) n

R * -

Vn

/ ^N

R ⁴ - (0> -

> N

-cox ¹¹ - / η Vr ⁵ Vo

-X "C0- <H

vp

-10- 254 Ö83

R ⁴ and R ⁵ are each preferably straight-chain alkyl, alkoxy, alkanoyloxy or alkoxycarbonyl having in each case 3 to 12 C atoms.

X "is O or S, preferably O. η is 0 or 1.

Particularly preferred are the compounds of sub-formulas Va, Vb, Vd and Vf, wherein R ⁴ and R ^{B are} each straight-chain alkyl or alkoxy each having 5 to 10 carbon atoms.

The compounds of subformulae Vc, Vh and Vi are useful as melting point depressants and are normally added to the base mixtures at not more than 5%, preferably 1 to 3%. R ⁴ and R ⁵ in the compounds of the sub-formulas Vc, Vh and Vi are preferably straight-chain alkyl having 2 to 7, preferably 3 to 5, carbon atoms. Another Verbi.ndungskiasse suitable for melting point reduction in the phases according to the invention is that of the formula

'-ΟΘ-

OOC-R-

wherein R ⁴ and R ^{5 have} the preferred meaning given for Vc, Vh and Vi.

Further suitable components with negative dielectric anisotropy are compounds containing the structural element M, N or O.

cn cn egg

-CH ₂ -CH- -CH-

M N O

Preferred compounds of this type correspond to the formulas VIb and VIc: h

R ¹ -Q ³ -CH ₉ -CH-Q ² -R "VIb

CN -

_R '-Q ³ _Q ⁴ -R <''VIC

R 'and R "in each case preferably denote straight-chain alkyl or alkoxy groups each having 2 to 10 carbon atoms Q ¹ and Q ^{2 are} each 1,4-phenylene, trans-1,4-cyclohexylene, 4,4'- Biphenylyl, 4- (trans-4-cyclohexyl) -phenyl, trans, trans-4,4'-bicyclohexyl or one of the groups Q ¹ and Q ^{2 is} also a single bond.

Q ³ and Q ^{4 are} each 1,4-phenylene, 4,4'-biphenyl or trans-1,4-cyclohexylene. One of the groups Q ³ and Q ⁴ may also be 1,4-phenylene, wherein at least one CH group is replaced by N. R "'is an optically active group having an asymmetric carbon atom of the structure

Cl CN

  ι · ι

-CH * - or -CH * -

 Particularly preferred compounds of the formula VIc are those of the formula VIc ':

wherein A is 1,4-phenylene or trans-1,4-cyclohexylene, Z ^{0 is} CH or N and η is O or 1.

The compounds of formula I are also useful as components of nematic liquid crystalline phases, e.g. to avoid reverse twist.

These liquid-crystalline phases according to the invention consist of 2 to 25, preferably 3 to 15 components, including at least one compound of the formula I. The other constituents are preferably selected from the nematic or nematogenic substances, in particular the known substances, from the classes of azoxybenzenes, Benzylidenaniline, biphenyls , Terphenyls, phenyl or cyclohexyl benzoates, cyclohexane-carboxylic acid phenyl or cyclohexyl esters, phenylcyclohexanes, cyclohexylbiphenyls, cyclohexylcyclohexanes, cyclohexylnaphthalenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, phenyl- or cyclohexylpyrimidines, phenyl- or cyclohexylpyridazines and their N-oxides, phenyl- or cyclohexyldioxanes, phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, optionally halogenated stilbenes, benzylphenyl ethers, tolans and substituted cinnamic acids.

The most important compounds which can be considered as components of such liquid-crystalline phases can be characterized by the formula Γ,

R'-L-G-E-R "I '

wherein L and E are each a carbo- or heterocyclic ring system of the 1,4-disubstituted benzene and cyclohexane rings, 4,4'-disubstituted biphenyl, phenyl-cyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidine and 1, 3-dioxane rings, 2,6-disubstituted naphthalene, di- and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline,

-CH = CH- -N (O) = N- -CH = CY- -CH = N (O) - -C = C- -CH ₂ -CH ₂ - -CO-O- -CH ₂ -O- -CO-S- -CH ₂ -S- -CH = N- -COO-Phe-COO-

or a C-C single bond,

Y is halogen, preferably chlorine, or-CN, and

R 'and R "is alkyl, alkoxy, alkanoyloxy, alkoxycarbonyl or alkoxycarbonyloxy having up to 18, preferably up to 8 carbon atoms, or one of these radicals on CN, NC, NO ₂ , CF ₃ , F, Cl or Br.

In most of these compounds, R 'and R "are different from each other, one of these radicals usually being an alkyl or alkoxy group, but other variants of the substituents provided are also common Many of these substances or mixtures thereof are commercially available are available according to literature methods.

The phases according to the invention contain about 0.1 to 99, preferably 10 to 95%, of one or more compounds of the formula I. Further preferred are liquid crystalline phases according to the invention containing 0.1-40, preferably 0.5-30% of one or more compounds the formula I.

The preparation of the phases according to the invention takes place in itself per se. In general, the components are dissolved in each other, useful at elevated temperature.

By means of suitable additives, the liquid-crystalline phases according to the invention can be modified so that they can be used in all hitherto known types of liquid-crystal display elements.

Such additives are known in the art and described in detail in the literature. For example, conducting salts, preferably ethyldimethyldodecylammonium 4-hexyloxybenzoate, tetrabutylammonium tetraphenylboranate or complex salts of crown ethers (cf., for example, BI Haller et al., Mol. Cryst. Liq. Cryst., Vol. TA, pages 249-258 [cf. 1973]) to improve the conductivity, pleochroic dyes for the preparation of colored guest-host systems or substances for changing the dielectric anisotropy, the viscosity and / or the orientation of the nematic phases are added.

Such substances are e.g. in DE-OS 2209127, 2240864, 2321 632, 2338281, 2450088, 2637430, 2853728 and 2902177.

embodiments

The following examples are intended to illustrate the invention without limiting it. Mp = melting point, bp = clearing point. Above and below, percentages are by weight; All temperatures are in degrees Celsius. "Working up" means adding water, extracting with methylene chloride, separating, drying the organic phase, evaporating and purifying the product by crystallisation and / or chromatography.

K: crystalline solid state, S: smectic phase (the index indicates the phase type), N: nematic state, Ch: cholesteric phase, I: isotropic phase. The number between two symbols indicates the transformation temperature in degrees Celsius.

Step Example! 1:

A mixture of 8 g of (S, S) -3-methyl-2-chloropentanoic acid, 16 g of optically active p- [5- (2,6-dimethylheptyl) -pyrimidin-2-yl] phenol [obtainable by condensation of (S) known from the literature -1,1,3,3-Tetraethoxy-2- (2,6-dimethylheptyl) -propane with 4-hydroxyphenylamidine hydrochloride], 11.6 g of N, -dicyclohexylcarbodiimide, O, 6g4-N, N-dimethylaminopyridine and 300 ml of dichloromethane is over Stirred at room temperature overnight. After filtering off the precipitated urea derivative, the filtrate is washed with dil. Hydrochloric acid and H ₂ O and the org. Phase worked up as usual. There are obtained (S, S) -3-methyl-2-chloropentanoic acid p- [5-2,6-dimethylheptyl) -pyrimidin-2-yl] -phenyl ester.

Example 2:

With exclusion of moisture, at 0 ^° C., a mixture of 4.9 g of optically active hydroquinone-4-cyano-4- (3,7-dimethyloctyD-cyclohexanecarboxylic acid ester [obtainable by esterification of 4-cyano-4- (3,7 -dimethyloctyl) -cyclohexanecarboxylic acid with hydroquinone monobenzyl ether and subsequent removal of the benzyl group by catalytic hydrogenation], 1.87 g of optically active 2-chloro-3-methylbutyric acid and 170 mg of 4-N, N'-dimethylaminopyridine in 30 ml of dichloromethane, 3.1 g of dicyclohexylcarbodiimide in 5 ml of dichloromethane After stirring at room temperature for 12 hours, filtration and customary working up of the filtrate, optically active 2-chloro-3-methylbutyric acid p- (4-cyano-4- [3,7-dimethyloctyl] -cyclohexylcarbonyloxy) -phenyl ester is obtained.

Analog are produced:

2-Chloro-3-methylbutyric acid p- (4-cyano-3- [2-methylbutyl] -cyclohexylcarbonyloxy) -phenyl ester 2-chloro-3-methylbutyric acid p- (4-cyano-4- [2-methylbutyl] - cyclohexyl) phenyl ester 2-Chloro-3-methylbutyric acid p- (4-cyano-4- [3,7-dimethyl-octyl] -cyclohexyl) -phenyl ester 2-chloro-3-methylbutyric acid p- (p- [3 -methylpentyl] -benzoyloxy) -phenyl ester 2-chloro-3-methylbutyric acid p- (trans-4- [4,8-dimethylnonyl] -cyclohexanecarbonyloxy) -phenyl ester.

Example 3:

An excess of (S, S) -3-methyl-2-chloropentanoic acid is reacted analogously to Example 1 with 4,4'-bis-hydroxybiphenyl. After the usual work-up, optically active 4,4'-bis (2-chloro-3-methylpentanoyloxy) -biphenyl is obtained. Analog are produced:

4,4'-bis- (2-chloro-3-methylbutyryloxy) biphenyl, F. 92 ° C, 4,4'-bis (2-chloro-4-methylpentanoyloxy) biphenyl, F. 70 ⁰ C

4,4'-bis (2-chloro-3-methylbutyryloxy) trans, trans-cyclohexylcyclohexane 4,4'-bis (2-chloro-4-methylpentanoyloxy) trans, trans-cyclohexylcyclohexane 4,4'-bis - (2-chloro-3-methylpentanoyloxy) -trans, trans-cyclohexylcyclohexane

Example 4:

A mixture of 5.3 g of p- [p- (4-cyano-4- (2-methylbutyl) cyclohexyl) -phenyl] -phenol (obtainable by alkaline ether cleavage from r-1-cyano-cis-4- (4 '). -propyloxybiphenyl-4-yl) -1- (2-methylbutyl) -cyclohexane with potassium tert-butoxide in NMP at 18O ⁰ C), 1.9 g of optically active 1-chloro-S-methyl-butyric acid and 170 g of DMAP suspended in 40 ml CH ₂ Cl ₂ . Then, at 0 ⁰ C 3.1 g of DCC in 5 ml CH ₂ Cl ₂ are added dropwise and stirred for 12 hours at room temperature. After separation of the Dicyclohexylhamstoffes and conventional workup gives optically active 2-chloro-3-methyl-butyric acid 4 '- (4-cyano-4- (2-methylbutyl) cyclohexyl) -biphenyl-4-yl ester.

Example 5:

By esterification of optically active 4- (4 '- (2-octyloxy) biphenyl-4-yl) -1-cyano-1- (2-hydroxypropyl) cyclohexane (available from 4- (4' - (2-octyloxy) -biphenyl-4-yl) -cyclohexanecarbonitrile by alkylation with optically active propylene oxide and lithium diisopropylamide as base) with optically active 2-chloro-3-methylbutyric acid gives optically active 1- [4-cis- (4 '- (2-octyloxy) biphenyl-4-yl) -r-1-cyancyclohexyl] -2-propyl- (2-chloro-3-methylbütyrat).

Examples:

To a solution of 2.4 g of optically active α-Pentyloxypropionsäurechlorid in 25 ml of pyridine is added dropwise a solution of optically active 4- (2-octyloxy) -4'-hydroxybiphenyl in toluene and heated for 2 hours at reflux. The usual work-up gives 4- (2-octyloxy) -4 '- (α-pentyloxypropanoyloxy) -biphenyl.

Analog are produced:

4,4'-bis (α-pentyloxypropanoyloxy) biphenyl 4,4'-bis (<x-butyloxypropanoyloxy) biphenyl 4,4'-bis (α-propyloxypropanoyloxy) biphenyl 4,4'-bis- (a-ethyloxypropanoyloxy) biphenyl

Example 7:

0.035 mol of 4,4'-bis-hydroxybiphenyl, 0.07 ml of (S) -3,7-dimethyloctanoic acid and 1 g of 4-N, N'-dimethylaminopyridine (DMAP) are dissolved in 150 ml of toluene. A solution of 16.0 g of dicyclohexylcarbodiimide (DCC) in 40 ml of toluene is added dropwise, the mixture is stirred overnight, chromatographed with toluene over silica gel, crystallized to give optically active 4,4'-bis (3,7-dimethyloctanoyloxy) biphenyl, F. 72-73 ° C.

Example 8:

25mmol 4.4 "-Terphenyldicarbonsäure (available by reacting dibromoterphenyl with CuCN in NMP and saponification of the dinitrile with KOH in diethylene glycol), 7.9 g of (S) -3,7-Dimethyloctanol and 0.12 g of DMAP are in 40 ml A solution of 9.9 g of DCC in 15 ml of toluene is added dropwise with stirring at room temperature, stirred overnight, chromatographed on silica gel with toluene, recrystallized to obtain 4.4 "bis- (3,7-dimethyloctyloxycarbonyl) -p-terphenyl.

Example 9:

To a solution of 16.2 g (0.3 mol) of sodium methylate and 24.8 g (0.1 mol) of 1-fluoro-2,5-di- (4-hydroxyphenyl) benzene in 150 ml of methanol in the boiling heat 80.5 g (0.3 mol) of (S) -3,7-dimethyl-1-iodoctane added dropwise. After 5 hours, work up as usual. After recrystallization, pure i-fluoro-O-W-iSJ-dimethyloctyloxy-phenyl-benzene is obtained.

Example A:

A liquid crystalline phase is prepared _# consisting of 3% 2-p-hexyloxyphenyl-5-heptylpyrimidine 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine 3% 2-p-octyloxyphenyl-5-heptylpyrimidine 3% 2-p-nonyloxyphenyl 5-heptylpyrimidine 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine 23% 2-p-Nonyloxyphenyl-5-nonylpyrimidine 28% r-1-cyano-cis-4- (4'-butyloxybiphenyl-4-ylM-octylcyclohexane 14% r-1-cyano-cis-4- (4'-heptylbiphenyl-4-yl) -1-hexylcyclohexane 6% r-1-cyano-cis-4- (trans-4-pentylcyclohexyl) -1- (trans 4-pentylcyclohexyl) cyclohexane and 10% 2-chloro-3-methylbutyric acid 4 '- [4-cyano-4- (3,7-dimethylheptyl) cyclohexyl] biphenyl-4-yl ester.

Example B:

A liquid crystalline phase _# consisting of 3% 2-p-hexyloxyphenyl-5-heptylpyrimidine 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine 3% 2-p-Octyloxyphenyl-5-heptylpyrimidine 3% 2-p-Nonyloxyphenyl-5-heptylpyrimidine 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine 23% 2-p-Nonyloxyphenyl-5-nonylpyrimidine 28% r-1-cyano-cis-4- (4'-butyloxybiphenyl-4-yl) -1-octylcyclohexane 14% r-1-cyan-cis-4- (4'-heptylbiphenyl-4-yl) -1-hexylcyclohexane

6% of r-1-cyano-cis-4- (trans-4-pentylcyclohexyl) -1- (trans-4-pentylcyclohexyl) cyclohexane and 10% of 4,4'-bis (2-chloro-3-methylbutyryloxy) biphenyl has at room temperature, a spontaneous polarization of 38nC / cm ² and a Sf / Ch conversion at 68 ⁰ C.

Example C:

A liquid crystalline phase is prepared consisting of 3% 2-p-hexyloxyphenyl-5-heptylpyrimidine 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine 3% 2-p-octyloxyphenyl-5-heptylpyrimidine 3% 2-p-nonyloxyphenyl 5-heptylpyrimidine

7% 2-p-hexyloxyphenyl-5-nonylpyrimidine 23% 2-p-Nonyloxyphenyl-5-nonylpyrimidine 28% r-1-cyano-cis-4- (4'-butyloxybiphenyl-4-yl) -1-octylcyclohexane 14% r-1-cyano-cis-4- (4'-heptylbiphenyl-4-yl) -1-hexylcyclohexane 6% r-1-cyano-cis-4- (trans-4-pentylcyclohexyl) -1- (trans-4 -pentylcyclohexyl) cyclohexane and 10% 3-methyl-2-chlorobutyric acid p- [5- (3-methylpentyl) -pyridin-2-yl] -phenyl ester.

Example D:

A liquid crystalline phase consisting of 3% 2-p-hexyloxyphenyl-5-heptylpyrimidine, 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine, 3% 2-p-octyloxyphenyl-5-heptylpyrimidine, 3% 2-p-nonyloxyphenyl-5 -heptylpyrimidine, 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine, 23% 2-p-nonyloxyphenyl-5-nonylpyrimidine, 30% r-1-cyano-cis-4- (4'-octyloxybiphenyl-4-yl) - 1-octylcyclohexane, 15% r-1-cyano-cis-4- (4'-heptyloxybiphenyl-4-yl) -1-hexylcyclohexane, 8% 3-methyl-2-chlorobutyric acid p- (5-nonylpyrimidine-2-) yl) -phenyl ester (optically active) and

5% S-methyl ^ chlorobutyric acid-p-tS-FSJ-pyrimidin ^ -yll-dimethyloctyO-phenyl ester (optically active) shows S £ / S _A 57 ° C, S _A / Ch 61 ⁰ C, Ch / 178 ⁰ C. and P _a =

Example E:

A liquid crystalline phase ₍ consisting of 3% 2-p-hexyloxyphenyl-5-heptylpyrimidine, 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine, 3% 2-p-octyloxyphenyl-5-heptylpyrimidine, 3% 2-p-nonyloxyphenyl 5-heptylpyrimidine, 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine, 25% 2-p-nonyloxyphenyl-5-nonylpyrimidine, 30% r-1-cyano-cis-4- (4'-octyloxybiphenyl-4-yl) 1-octylcyclohexane 15% r-1-cyano-cis-4- (4'-heptylbiphenyl-4-yl) -1-hexylcyclohexane 6% 3-methyl-2-chlorobutyric acid p- (5-heptylpyridin-2-yl ) -phenyl ester (optically active) and

5% of 2,5-bis [p- (3-methyl-2-chlorobutyryloxy) -phenyl] -pyridine (optically active) shows S * / S _A 6rC, SA / Ch 64 ° C, Ch / I 78 ⁰ C and P _s = lenC / cm ² .

Example F:

A liquid crystalline phase consisting of

3% 2-p-hexyloxyphenyl-5-heptylpyrimidine, 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine, 3% 2-p-octyloxyphenyl-5-heptylpyrimidine, 3% 2-p-nonyloxyphenyl-5-heptylpyrimidine, 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine, 23% 2-p-nonyloxyphenyl-5-nonylpyrimidine, 28% r-1-cyano-cis-4- (4'-butyloxybiphenyl-4-yl) -1-octylcyclohexane 14% r-1-cyano-cis-4- (4'-heptylbiphenyl-4-yl) -1-hexylcyclohexane 6% r-1-cyano-1- (trans-4-pentylcyclohexyl) -cis-4- (trans-4 -pentylcyclohexyl) cyclohexane and 10% optically active 4,4'-bis- [1- (ethoxycarbonyl) -ethoxy] -biphenyl show S? / S _A 54 ° C, S _A / Ch 58 ° C, Ch / I 78 ⁰ C and P _s = 2nC / cm ² .

Example G:

A liquid crystalline phase consisting of 3% 2-p-hexyloxyphenyl-5-neptylpyrimidine, 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine, 3% 2-p-octyloxyphenyl-5-heptylpyrimidine, 3% 2-p-nonyloxyphenyl-5 -heptylpyrimidine, 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine, 23% 2-p-nonyloxyphenyl-5-nonylpyrimidine, 28% r-1-cyano-cis-4- (4'-butyloxybiphenyl-4-yl) - 1-octylcyclohexane 14% r-1-cyano-cis-4- (4'-heptylbiphenyl-4-yl) -1-hexylcyclohexane 6% r-1-cyano-1- (trans-4-pentylcyclohexyl) -cis-4 - (trans-4-pentylcyclohexyl) cyclohexane and 10% optically active 4,4'-bis- (a-butyloxypropanoyloxy) -biphenyl shows SyS _A 51 ° C, S _A / Ch 53 ° C, Ch / I 76 ° C. and P ₃ = 2nC / cm ² .

Example H:

A liquid-crystalline phase consisting of 3% 2-p-hexyloxyphenyl-5-heptylpyrimidine, 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine, 3% 2-p-octyloxyphenyl-5-heptylpyimidine, 3% 2-p-nonyloxyphenyl 5-heptylpyrimidine, 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine, 23% 2-p-nonyloxyphenyl-5-nonylpyrimidine, 28% r-1-cyano-cis-4- (4'-butyloxybiphenyl-4-yl) 1-octylcyclohexane, 14% r-1-cyano-cis-4- (4'-hexylbiphenyl-4-yl) -1-heptylcyclohexane, 6% r-1-cyano-cis-4- (trans-4-pentylcyclohexyl ) -1- (trans-4-pentylcyclohexyl) cyclohexane and 10% 4,4'-bis (2-chloro-3-methylbutyryloxy) trans; Trans-cyclohexylcyclohexane (optically active) shows S p / S _A 53 ° C, S _A / Ch 84 ° C, Ch / 192 ⁰ C and P _s = ^ nC / cm ² .

Example I:

A liquid crystalline phase consisting of 3% 2-p-hexyloxyphenyl-5-heptylpyrimidine, 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine, 3% 2-p-octyloxyphenyl-5-heptylpyrimidine, 3% 2-p-nonyloxyphenyl-5 -heptylpyrimidine, 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine, 23% 2-p-nonyloxyphenyl-5-nonylpyrimidine, 28% r-1-cyano-cis-4- (4'-butyloxybiphenyl-4-yl) - 1-octylcyclohexane, 14% r-1-cyano-cis-4- (4'-hexylbiphenyl-4-yl) -1-heptylcyclohexane, 6% r-1-cyano-cis-4- (trans-4-pentylcyclohexyl) -1- (trans-4-pentylcyclohexyl) cyclohexane and 10% 4,4'-bis (2-chloro-4-methylpentanoyloxy) trans, trans-cyclohexylcyclohexane (optically active) show S * / S _A 58 ° C , S _A / Ch 82 ⁰ C, Ch / I 88 ⁰ C and P _s = 14nC / cm ² .

BeispielJ:

A liquid crystalline phase consisting of 3% 2-p-hexyloxyphenyl-5-heptylpyrimidine, 3% 2-p-heptyloxyphenyl-5-heptylpyrimidine, 3% 2-p-octyloxyphenyl-5-heptylpyrimidine, 3% 2-p-nonyloxyphenyl-5- heptylpyrimidine, 7% 2-p-hexyloxyphenyl-5-nonylpyrimidine, 23% 2-p-nonyloxyphenyl-5-nonylpyrimidine, 28% r-1-cyano-cis-4- (4'-butyloxybiphenyl-4-yl) -1 octyl cyclohexane, 14% r-1-cyano-cis-4- (4'-hexylbiphenyl-4-yl) -1-heptylcyclohexane, 6% r-1-cyano-cis-4- (trans-4 -pentylcyclohexyl) -1- (trans-4-pentylcyclohexyl) cyclohexane and 10% of 4,4'-bis (2-chloro-3-methylpentanoyloxy) trans, trans-cyclohexylcyclohexane (optically active) show S? / S _A 55 ° C, S _A / Ch 83 ° C, CH / I 90 ⁰ C and P ₃ = 13nC / cm ² .

Claims (2)

claims: 1. Chiral tutted smectic liquid-crystalline phase having at least two liquid-crystalline components, characterized in that it contains at least one optically active compound of the formula I, R ¹ -C * HX-QA ⁴ -Z ¹ -A ² - (Z ² -A ³ ) _n -X'-Q'-C * HY'-R ⁵ _# R ^{1 is} an alkyl or perfluoroalkyl group each having 1-12 C atoms, wherein one or two non-adjacent CH ₂ - or CF ₂ groups by O atoms and / or, -CO groups and / or -CO-OG groups and / or -CH = CH groups and / or -CHHalogen and / or -CH = groups and / or -CH-halogen and / or -CHCN groups and / or -0-CO-CH-halo and / or -O-CO-CHCN groups replaced could be,
R ^{5 is} an alkyl group of 1 to 15 carbon atoms different from Y ', wherein also one or two non-adjacent CH ₂ groups can be replaced by -O-, -CO-, -O-C0-, -CO-O- and / or -CH = CH- η, each unsubstituted or by one or two F and / or Cl atoms and / or CH ₃ groups and / or CN groups substituted 1,4-phenylene, wherein also one or two CH groups may be replaced by N, 1,4-cyclohexylene, wherein also one or _two non-adjacent CH ₂ groups may be replaced by O atoms and / or S atoms, piperidine-1,4-diyl, 1,4-bicyclo (2,2,2) -octylene, naphthalene-2 , 6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl groups, jewei Is -CO-O-, -0-C0-, -CH ₂ CH ₂ -, -OCH ₂ -, -CH ₂ O-, -C = C- or a Single bond, Halogen, CN or CH ₃ , O or 1, Alkylene having 1 to 4 carbon atoms, in which also a CH ₂ group is represented by -O-, -CO-, -O-C0-, -CO-O-, -CH = CH-COO-, -CH = CH-, CHhalogen and / or CHCN-substituted, or a single bond, -CO-O-, -O-C0-, -O-CO-O-, -CO-, -O-, -S-, -CH = CH-, -CH = CH-COO- or a single bond, alkylene with 1 to 5 C atoms, in which also a non-X 'linked CH ₂ group may be replaced by -O-, -CO-, -O-CO, -CO-O- or -CH = CH-, or a Single bond, and CN, halogen, methyl or methoxy
with the proviso that R ¹ and / or R ^{5 is} a branched alkyl group having 3 to 12 C atoms, if C * HX-Q-CH-halo-CO-O- and / or -X'-Q'- C * HY'-O-CO-ÖHHalogen means contains. 2. Use of the compounds of the formula I according to claim 1, characterized in that they are used as components of liquid-crystalline phases. Z ¹ and
Z ²