Liquid crystal mixture and liquid crystal display

Abstract

The present invention relates to compounds of formula I, wherein R 11 , R 21 , A 11 , A, Z, X 11 , X 21 , Y 11 , Y 12 、Sp 11 、Sp 21 , o and p have one of the meanings given in claim 1. The invention further relates to a process for producing compounds of the formula I, the use of said compounds in LC media and LC media comprising one or more compounds of the formula I. Furthermore, the invention relates to a process for producing such LC media, the use of such media in LC devices and LC devices comprising the LC media of the invention. The invention further relates to a process for producing such liquid crystal displays and the use of the liquid crystal mixtures of the invention for producing such liquid crystal displays.

Description

[0001] The present invention relates to compounds of formula I,

[0002]

[0003] Where R 11 , R 21 , A 11 , A, Z, X 11 , X 21 , Y 11 , Y 12 、Sp 11 、Sp 21 , o and p have one of the meanings given in claim 1. The invention further relates to a process for producing said compounds, the use of said compounds in LC media and LC media comprising one or more compounds of the formula I. Furthermore, the invention relates to a process for producing such LC media, the use of such media in LC devices and LC devices comprising the LC media of the invention. The invention further relates to a process for producing such liquid crystal displays and the use of the liquid crystal mixtures of the invention for producing such liquid crystal displays.

[0004] Background and prior art

[0005] Liquid-crystalline media have been used for decades in electro-optical displays for the display of information. The liquid-crystalline displays used currently are generally those of the TN (“twisted nematic”) type. However, these have the disadvantage of a strong viewing angle dependence of the contrast.

[0006] In addition, so-called VA (“vertically aligned”) displays are known, which have a wider viewing angle. The LC cell of a VA display contains an LC medium layer between two transparent electrodes, wherein the LC medium generally has a negative dielectric (DC) anisotropy value. In the switched-off state, the molecules of the LC layer are aligned perpendicularly to the electrode surfaces (homeotropic) or have an inclined homeotropic alignment. When a voltage is applied to the two electrodes, the LC molecules parallel to the electrode surfaces realign. In addition, so-called IPS (“in-plane switching”) displays and later FFS (“fringe field switching”) displays have been reported (see in particular SH Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, 1028), which contain two electrodes on the same substrate, one of which is structured in a comb-shaped manner and the other is not structured. This generates a strong so-called “fringe field”, i.e. a strong electric field close to the edges of the electrodes, and an electric field with both a strong vertical component and a strong horizontal component throughout the cell. FFS displays have a low viewing angle dependence of the contrast. FFS displays usually contain an LC medium with positive dielectric anisotropy and an alignment layer, usually polyimide, which provides a planar alignment for the molecules of the LC medium.

[0007] Furthermore, FFS displays have been disclosed (see SH Lee et al., Appl. Phys. Lett. 73 (20), 1998, 2882-2883 and SH Lee et al., Liquid Crystals 39 (9), 2012, 1141-1148) which have similar electrode designs and layer thicknesses as FFS displays, but comprise layers of LC media with negative dielectric anisotropy instead of LC media with positive dielectric anisotropy. LC media with negative dielectric anisotropy show more favorable director orientations with less tilt and more twist orientations than LC media with positive dielectric anisotropy, as a result of which these displays have higher transmittance.

[0008] Another development is the so-called PS (polymer persistent) or PSA (polymer persistent alignment) displays, for which the term “polymer stabilized” is also occasionally used. PSA displays are characterized by a shortened response time without significant adverse effects on other parameters, such as, in particular, the viewing angle dependence of the advantageous contrast.

[0009] In these displays, small amounts (e.g. 0.3 wt. %, typically <1 wt. %) of one or more polymerizable compounds are added to the LC medium and, after introduction into the LC cell, polymerized or crosslinked in situ between the electrodes with or without applied voltage, typically by UV photopolymerization. The addition of polymerizable mesogens or liquid crystal compounds (also called reactive mesogens or "RMs") to the LC mixture has proven to be particularly suitable. PSA technology has hitherto been used primarily for LC media with negative dielectric anisotropy.

[0010] Unless otherwise indicated, the term "PSA" is used hereinafter as a representative of both PS displays and PSA displays.

[0011] At the same time, the PSA principle is being used in a variety of classical LC displays. Thus, for example, PSA-VA, PSA-OCB, PSA-IPS, PSA-FFS and PSA-TN displays are known. Preferably, the polymerization of the polymerizable compound is carried out under applied voltage in the case of PSA-VA and PSA-OCB displays, and under applied or unapplied voltage in the case of PSA-IPS displays. As can be shown in the test box, the PS (A) method produces a "pre-tilt" in the box. In the case of PSA-OCB displays, for example, the curved structure can be stabilized so that the compensation voltage is unnecessary or can be reduced. In the case of PSA-VA displays, the pre-tilt has a positive effect on the response time. Standard MVA or PVA pixel and electrode layouts can be used for PSA-VA displays. However, in addition, it can also be managed, for example, with only one structured electrode side and without protrusions, which significantly simplifies the manufacturing and at the same time produces a very good light contrast while producing a very good light transmittance.

[0012] PSA-VA displays are described, for example, in JP 10-036847 A, EP 1 170 626 A2, US 6,861,107, US 7,169,449, US 2004 / 0191428 A1, US 2006 / 0066793 A1 and US 2006 / 0103804 A1. PSA-OCB displays are described, for example, in T.-J-Chen et al., Jpn. J. Appl. Phys. 45, 2006, 2702-2704 and SH Kim, L.-C-Chien, Jpn. J. Appl. Phys. 43, 2004, 7643-7647. PSA-IPS displays are described, for example, in US 6,177,972 and Appl. Phys. Lett. 1999, 75 (21), 3264. PSA-TN displays are described, for example, in Optics Express 2004, 12 (7), 1221. PSA-VA-IPS displays are described, for example, in WO 2010 / 089092 A1.

[0013] As with conventional LC displays described above, PSA displays can be operated as active matrix or passive matrix displays. In the case of active matrix displays, the individual pixels are typically addressed by integrated non-linear active elements such as transistors (e.g. thin film transistors or "TFTs"), while in the case of passive matrix displays, the individual pixels are typically addressed by multiplexing, both methods being known from the prior art.

[0014] In the prior art, polymerizable compounds such as those of the following formula are used for PSA-VA:

[0015]

[0016] wherein P represents a polymerizable group, typically an acrylate or methacrylate group, as described, for example, in US 7,169,449.

[0017] Under the polymer layer inducing the above mentioned pretilt, the alignment layer (usually polyimide) provides the initial alignment of the liquid crystal without taking into account the polymer stabilization step of the production process.

[0018] The amount of work involved in the manufacture of polyimide layers, the processing of the layers and the modification of the bumps or polymer layers is relatively large. Therefore, a simplified technology would be needed which would reduce the manufacturing costs on the one hand and help to optimize the image quality (viewing angle dependency, contrast, response time) on the other hand.

[0019] Rubbed polyimide has long been used to align liquid crystals. The rubbing method causes a variety of problems: non-uniformity (mura), contamination, electrostatic discharge problems, residues, etc.

[0020] Photoalignment is a technique for achieving friction-free alignment of liquid crystals (LCs) by replacing friction with a light-induced directional ordering of the alignment surface. This can be achieved via the mechanisms of photolysis, photodimerization and photoisomerization with the aid of polarized light (NA Clark et al., Langmuir 2010, 26(22), 17482-17488 and references cited therein). However, a suitably derivatized polyimide layer comprising photoreactive groups is still required. Another improvement would be to avoid the use of polyimide altogether. For VA displays, this is achieved by adding a self-aligning agent to the LC which induces in situ homeotropic alignment via a self-assembly mechanism as disclosed in WO 2012 / 104008 and WO 2012 / 038026.

[0021] NA Clark et al., Langmuir 2010, 26 (22), 17482-17488 have shown that it is possible to self-assemble compounds of the following structure onto a substrate to obtain a monolayer that can be photoaligned to induce planar alignment of the liquid crystal. However, a separate step of self-assembly is required prior to fabrication of the LC cell, and the nature of the azo group results in reversibility of the alignment upon exposure to light.

[0022] Another functional group known to allow photo-alignment is phenylvinylcarbonyloxy (cinnamate). Photo-crosslinkable cinnamate is known from the prior art, for example as disclosed in EP0763552 of the following structure: From such compounds, polymers such as the following can be obtained This material is used in a photoalignment method as disclosed in WO 99 / 49360 to obtain an alignment layer for liquid crystals.A disadvantage of the alignment layer obtained by this method is that it provides a lower voltage holding ratio (VHR) compared to polyimides.

[0023] In WO 00 / 05189 polymerisable direactive mesogenic cinnamates are disclosed for use as, for example, optical retarders in polymerisable LC mixtures.

[0024]

[0025] GB 2 306 470 A discloses structurally related compounds of the formula containing two cinnamic acid moieties for use as components in liquid crystal polymer films. Such compounds have not been used or suggested for use as photoalignment agents.

[0026] Very similar compounds are disclosed in BMI van der Zande et al., Liquid Crystals, Vol. 33, No. 6, June 2006, 723-737 as patterning retarders in the field of liquid crystal polymers and have the following structure:

[0027]

[0028] WO 2017 / 102068 A1 discloses the same structure for the purpose of a polyimide-free planar photoalignment method.

[0029] In addition, MHLee et al. disclosed in Liquid Crystals (https: / / doi.org / 10.1080 / 02678292.2018.1441459) a polyimide-free surface photoalignment method induced by a polymerizable liquid crystal containing a cinnamate moiety of the following formula:

[0030]

[0031] Therefore, there is a great need for novel photoreactive mesogens that are able to photoalign liquid crystal mixtures in situ (ie after assembly of the display) by means of linearly polarized light.

[0032] In addition to this requirement, the corresponding photoreactive mesogens should preferably also provide LC displays with an advantageously high dark state and an advantageously high voltage holding ratio at the same time. Furthermore, the amount of photoreactive mesogens in the nematic LC medium should be as low as possible and the production method should be obtainable by methods that are compatible with common mass production methods, for example with regard to advantageously short processing times.

[0033] Those skilled in the art will immediately understand other objects of the present invention from the following detailed description.

[0034] Surprisingly, the inventors have found that one or more of the above-mentioned objects can be achieved by providing compounds according to claim 1 .

[0035] Terms and Definitions

[0036] Photoreactive groups according to the invention are functional groups of molecules which cause a change in the molecular geometry by bond rotation, skeletal rearrangement or atom or group transfer, or by dimerization upon irradiation with light of a suitable wavelength which can be absorbed by the molecule.

[0037] As used herein, the term "mesogenic group" is known to those skilled in the art and is described in the literature and refers to a group that substantially contributes to the generation of a liquid crystal (LC) phase in a low molecular weight or polymeric substance due to its anisotropy of attraction and repulsion interactions. A compound containing a mesogenic group (mesogenic compound) does not necessarily have an LC phase per se. A mesogenic compound may also exhibit LC phase behavior only after mixing with other compounds and / or after polymerization. Typical mesogenic groups are, for example, rigid rod-shaped or disc-shaped units. Terms and definitions used in connection with mesogenic or LC compounds are given in Pure Appl. Chem. 2001, 73 (5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

[0038] The photoreactive mesogen according to the present invention is a mesogenic compound comprising one or more photoreactive groups.

[0039] Examples of photoreactive groups are -C=C- double bonds and azo groups (-N=N-).

[0040] Examples of molecular structures and substructures comprising such photoreactive groups are stilbene, (1,2-difluoro-2-phenyl-vinyl)-benzene, cinnamate, 4-phenylbut-3-en-2-one, chalcone, coumarin, chromone, pentalenone and azobenzene.

[0041] According to the present application, the term "linearly polarized light" refers to light that is at least partially linearly polarized. Preferably, the aligning light is linearly polarized with a degree of polarization greater than 5:1. The wavelength, intensity and energy of the linearly polarized light are selected depending on the photosensitivity of the photo-alignable substance. Typically, the wavelength is in the UV-A, UV-B and / or UV-C range or in the visible light range. Preferably, the linearly polarized light comprises light with a wavelength of less than 450 nm, more preferably less than 420 nm, while the linearly polarized light preferably comprises light with a wavelength longer than 280 nm, preferably greater than 320 nm, more preferably more than 350 nm.

[0042] The term "organic group" means a carbon or hydrocarbon group.

[0043] The term "carbonyl" refers to a monovalent or polyvalent organic group containing at least one carbon atom, wherein it does not contain other atoms (such as, -C≡C-) or optionally contains one or more other atoms, such as N, O, S, P, Si, Se, As, Te or Ge (e.g., carbonyl, etc.). The term "hydrocarbyl" refers to a carbon group that additionally contains one or more H atoms and optionally one or more heteroatoms (such as, N, O, S, P, Si, Se, As, Te or Ge).

[0044] "Halogen" indicates F, Cl, Br or I.

[0045] The carbon or hydrocarbon group may be a saturated or unsaturated group. An unsaturated group is, for example, an aryl, an alkenyl or an alkynyl group. The carbon or hydrocarbon group having 3 or more atoms may be straight chain, branched and / or cyclic and may also contain a spiro bond or a condensed ring.

[0046] The terms "alkyl," "aryl," "heteroaryl," and the like also encompass multivalent groups such as alkylene, arylene, heteroarylene, and the like.

[0047] The term "aryl" refers to an aromatic carbon group or a group derived therefrom. The term "heteroaryl" refers to an "aryl" as defined above containing one or more heteroatoms.

[0048] Preferred carbyl and hydrocarbyl groups are optionally substituted alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy groups having 1 to 40, preferably 1 to 25, particularly preferably 1 to 18 C atoms; optionally substituted aryl or aryloxy groups having 6 to 40, preferably 6 to 25 C atoms; or optionally substituted alkaryl, aralkyl, alkylaryloxy, arylalkoxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy groups having 6 to 40, preferably 6 to 25 C atoms.

[0049] Further preferred carbon and hydrocarbon groups are C1-C 40 Alkyl, C2-C 40 Alkenyl, C2-C 40 Alkynyl, C3-C 40 Allyl, C4-C 40 Alkyldiene, C4-C 40 Polyene, C6-C 40 Aryl, C6-C 40 Alkyl aryl, C6-C 40 Arylalkyl, C6-C 40 Alkyl aryloxy, C6-C 40 Arylalkoxy, C2-C 40 Heteroaryl, C4-C40 Cycloalkyl, C4-C 40 Particularly preferred is C1-C 22 Alkyl, C2-C 22 Alkenyl, C2-C 22 Alkynyl, C3-C 22 Allyl, C4-C 22 Alkyldiene, C6-C 12 Aryl, C6-C 20 Aralkyl and C2-C 20 Heteroaryl.

[0050] Other preferred carbon and hydrocarbon radicals are straight-chain, branched or cyclic alkyl radicals having 1 to 40, preferably 1 to 25, C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN, and in which one or more non-adjacent CH2 groups may each be independently of one another by -C(R) in such a way that the O and / or S atoms are not directly connected to one another. z )=C(R z )-、-C≡C-、-N(R z )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- substitution.

[0051] R z Preferably represents H, halogen, a straight-chain, branched or cycloalkyl chain having 1 to 25 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O-, and in which one or more H atoms may be replaced by fluorine, an optionally substituted aryl or aryloxy group having 6 to 40 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms.

[0052] Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl and perfluorohexyl.

[0053] Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl and cyclooctenyl.

[0054] Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl and octynyl.

[0055] Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, 2-methylbutoxy, n-pentoxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy and n-dodecyloxy.

[0056] Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino and phenylamino.

[0057] Aryl and heteroaryl groups may be monocyclic or polycyclic, i.e. they may contain one ring (e.g. phenyl) or two or more rings, which may also be fused (e.g. naphthyl) or covalently bonded (e.g. biphenyl), or comprise a combination of fused and linked rings. Heteroaryl groups contain one or more heteroatoms, preferably selected from O, N, S and Se. Ring systems of this type may also contain independent non-conjugated units, as is the case, for example, in the fluorene basic structure.

[0058] Particularly preferred are mono-, bi- or tricyclic aryl radicals having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl radicals having 2 to 25 C atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6- or 7-membered aryl and heteroaryl radicals, in which, in addition, one or more CH groups may be replaced by N, S or O in such a way that the O atoms and / or S atoms are not directly connected to one another.

[0059] Preferably, the aryl group is derived from, for example, the following parent structure: benzene, biphenyl, terphenyl, [1,1':3',1"]terphenyl, naphthalene, anthracene, binaphthyl, phenanthrene, pyrene, dihydropyrene, Perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, etc.

[0060] Preferred heteroaryl groups are, for example, 5-membered rings such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-oxadiazole, 4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, a 6-membered ring such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine or a fused group such as indole, isoindole, indolizine, indazole, benzimidazole, benzoimidazole, triazole, purine, naphthimidazole, phenanthimidazole, pyridimidazole, pyrazimidazole, quinoxalinimidazole, benzoxazole, naphthimidazole, anthraxidazole, phenanthimidazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzisoquinoline, acridine, phenothiazine The heteroaryl group may also be substituted by an alkyl, alkoxy, sulfanyl, fluorine, fluorine, or other aryl or heteroaryl group.

[0061] (Non-aromatic) alicyclic and heterocyclic groups include both saturated rings, i.e. rings containing only single bonds, and partially unsaturated rings, i.e. those which may also contain multiple bonds. The heterocyclic ring contains one or more heteroatoms, preferably selected from Si, O, N, S and Se.

[0062] (Non-aromatic) alicyclic groups and heterocyclic groups can be monocyclic, i.e. contain only one ring (e.g. cyclohexane), or polycyclic, i.e. contain multiple rings (e.g. decalin or bicyclooctane). Saturated groups are particularly preferred. In addition, mono-, bi- or tricyclic groups with 3-25 C atoms are preferred, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-, 7- or 8-membered carbocyclic groups, wherein in addition, one or more C atoms may be substituted by Si and / or one or more CH groups may be substituted by N and / or one or more non-adjacent CH2 groups may be substituted by-O- and / or-S-.

[0063] Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine; 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine; 7-membered groups, such as cycloheptane; and condensed groups, such as tetralin, decalin, indane, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindan-2,5-diyl.

[0064] The aryl, heteroaryl, carbonyl and hydrocarbon groups optionally have one or more substituents, which are preferably selected from the group comprising silyl, sulfonic acid, sulfonyl, formyl, amine, imine, nitrile, mercapto, nitro, halogen, C 1-12 Alkyl, C 6-12 Aryl, C 1-12 Alkoxy, hydroxy or a combination of these groups.

[0065] Preferred substituents are, for example, groups promoting solubility, such as alkyl or alkoxy groups, and electron withdrawing groups, such as fluoro, nitro or nitrile.

[0066] Unless otherwise indicated, preferred substituents (also referred to as "L" above and below) are F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R z )2, -C(=O)Y 1 、C(=O)R z 、-N(R z )2, where R z has the meaning indicated above, and Y 1 represents halogen, optionally substituted silyl or aryl having 6 to 40, preferably 6 to 20 C atoms, and straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, preferably 2 to 12 C atoms, where one or more H atoms may optionally be replaced by F or Cl.

[0067] "Substituted silyl or aryl" preferably refers to substituted silyl or aryl groups. y1 、-OR y1 、-CO-R y1 、-CO-OR y1 、-O-CO-R y1 OR-O-CO-OR y1 Substitution, where R y1 has the meaning indicated above.

[0068] Particularly preferred substituents L are, for example, F, Cl, CN, CH3, C2H5, -CH(CH3)2, OCH3, OC2H5, CF3, OCF3, OCHF2, OC2F5, and phenyl.

[0069] Above and below, "halogen" means F, Cl, Br or I.

[0070] Above and below, the terms "alkyl", "aryl", "heteroaryl" etc. also encompass polyvalent groups such as alkylene, arylene, heteroarylene etc.

[0071] The term "director" is known in the prior art and means the preferred orientation direction of the long molecular axis (in the case of rod-shaped compounds) or the short molecular axis (in the case of discotic compounds) of the liquid crystal molecules. In the case of a uniaxial ordering of such anisotropic molecules, the director is the axis of anisotropy.

[0072] "Alignment" or "orientation" refers to the alignment (directional ordering) of anisotropic units of a material (such as small molecules or fragments of macromolecules) in a common direction called the "alignment direction". In an alignment layer of a liquid crystal material, the liquid crystal director is aligned with the alignment direction so that the alignment direction corresponds to the direction of the anisotropic axis of the material.

[0073] For example, the term "planar alignment" in a layer of liquid crystal material means that a certain proportion of the liquid crystal molecules have their long molecular axes (in the case of rod-shaped compounds) or short molecular axes (in the case of discotic compounds) aligned substantially parallel (about 180°) to the plane of the layer.

[0074] For example, the term "homeotropic alignment" in a layer of liquid crystal material means that a certain proportion of the long molecular axes (in the case of rod-shaped compounds) or short molecular axes (in the case of discotic compounds) of the liquid crystal molecules are oriented at an angle θ ("tilt angle") of about 80° to 90° relative to the plane of the layer.

[0075] The term "homogeneous orientation" or "homogeneous alignment" of a liquid crystal material, for example in a material layer, means that the long molecular axes (in the case of rod-shaped compounds) or the short molecular axes (in the case of discotic compounds) of the liquid crystal molecules are oriented substantially in the same direction. In other words, the lines of the liquid crystal directors are parallel.

[0076] Unless explicitly stated otherwise, the wavelength of light generally referred to in this application is 550 nm.

[0077] The birefringence Δn in this paper is defined by the following equation:

[0078] Δn=n e -n o

[0079] where n e is an extraordinary refractive index and n o is the ordinary refractive index, and the effective average refractive index n av. It is given by the following equation.

[0080] n av. =[(2n o 2 +n e 2 ) / 3] 1 / 2

[0081] Extraordinary refractive index n e and the ordinary refractive index n o It can be measured using an Abbe refractometer.

[0082] In this application, the term "dielectrically positive" is used for compounds or components with Δε>3.0, "dielectrically neutral" is used for compounds or components with -1.5≤Δε≤3.0 and "dielectrically negative" is used for compounds or components with Δε<-1.5. Δε is measured at a frequency of 1 kHz and at 20°C. The dielectric anisotropy of each compound is determined by the results of a 10% solution of each single compound in a nematic host mixture. In the case where the solubility of each compound in the host medium is less than 10%, its concentration is reduced by one-half until the resulting medium is stable enough to at least allow its properties to be measured. However, preferably, the concentration is maintained at at least 5% to maintain the highest possible significance of the results. The capacitance of the test mixture is measured in a box with both homeotropic and planar alignment. The box thickness of both types of boxes is about 20 μm. The applied voltage is a rectangular wave with a frequency of 1 kHz and the root mean square value is typically 0.5V to 1.0V, but it is always selected to be lower than the capacitance threshold of each test mixture.

[0083] Δε is defined as (ε || -ε ⊥ ), and ε av. is (ε || +2ε ⊥ ) / 3. The dielectric permittivity of the compound is determined from the change in each value of the host medium after the addition of the compound of interest. The value is extrapolated to a concentration of 100% of the compound of interest. Typical host media are ZLI-4792 or ZLI-2857, both available from Merck, Darmstadt.

[0084] For the present invention,

[0085] and

[0086] represents trans-1,4-cyclohexylene,

[0087] and It represents 1,4-phenylene.

[0088] For the present invention, the group -CO-O-, -COO-, -C(=O)O- or -CO2- is represented by The ester group, and the group -O-CO-, -OCO-, -OC(=O)-, -O2C- or -OOC- is represented by Ester group.

[0089] Furthermore, definitions as given in C. Tschierske, G. Pelzl and S. Diele, Angew. Chem. 2004, 116, 6340-6368 shall apply to undefined terms in this application in connection with liquid crystal materials.

[0090] Detailed description

[0091] In detail, the present invention relates to a photoreactive mesogen of formula I

[0092]

[0093] in

[0094] A 11 Representation group

[0095]

[0096] Furthermore, one or more H atoms in these groups may be replaced by L, and / or one or more CH groups may be replaced by N,

[0097] A represents independently at each occurrence

[0098] a) the group consisting of 1,4-phenylene and 1,3-phenylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L,

[0099] b) the group consisting of saturated, partially unsaturated or fully unsaturated and optionally substituted polycyclic radicals having 5 to 20 ring C atoms, one or more of which may additionally be replaced by heteroatoms, which are preferably selected from the group consisting of:

[0100]

[0101]

[0102] Furthermore, one or more H atoms in these groups may be replaced by L, and / or one or more double bonds may be replaced by single bonds, and / or one or more CH groups may be replaced by N,

[0103] c) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, in which one or more non-adjacent CH2 groups may be replaced by -O- and / or -S- and in which one or more H atoms may be replaced by F, or

[0104] d) the group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L,

[0105] L, in each occurrence, identically or differently, represents -OH, -F, -Cl, -Br, -I, -CN, -NO2, SF5, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R z )2, -C(=O)R z 、-N(R z )2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms or linear or branched or cyclic alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, preferably 1 to 12 C atoms, more preferably 1 to 6 C atoms, in which one or more H atoms may be replaced by F or Cl, or represents X 21 -Sp 21 -R 21 ,

[0106] M represents -O-, -S-, -CH2-, -CHR z -or-CR y R z -,and

[0107] R y and R z each independently of one another represents H, CN, F or alkyl having 1 to 12 C atoms, wherein one or more H atoms may moreover be replaced by F, preferably represents H, methyl, ethyl, propyl, butyl, more preferably represents H or methyl,

[0108] Especially for H,

[0109] Y 11 and Y 12 each independently of one another represents H, F, phenyl or an optionally fluorinated alkyl group having 1 to 12 C atoms, preferably represents H, methyl, ethyl, propyl, butyl, more preferably represents H or methyl,

[0110] Especially for H,

[0111] Z represents, independently of each other, a single bond, -COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -OCF2-, -CF2O-, -(CH2) at each occurrence n -, -CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, -CO-S-, -S-CO-, -CS-S-, -S-CS-, -S-CSS- or -C≡C-,

[0112] Preferably represents a single bond, -COO-, -OCO-, -OCF2-, -CF2O- or -(CH2) n -,

[0113] More preferably represents a single bond, -COO- or -OCO-,

[0114] n represents an integer between 2 and 8, preferably represents 2,

[0115] o and p each and independently represent 0, 1 or 2, preferably represent 1,

[0116] X 11 and X 21 represents, independently of one another at each occurrence, a single bond, -CO-O-, -O-CO-, -O-COO-, -O-, -CH=CH-, -C≡C-, -CF2-O-, -O-CF2-, -CF2-CF2-, -CH2-O-, -O-CH2-, -CO-S-, -S-CO-, -CS-S-, -S-CS-, -S-CSS- or -S-,

[0117] preferably represents a single bond, -CO-O-, -O-CO-, -O-COO- or -O-,

[0118] More preferably represents a single bond or -O-,

[0119] Sp 11 and Sp 21each and independently at each occurrence represents a single bond or a spacer group comprising 1 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH2 groups may also be replaced by -O-, -S-, -NH-, -N(CH3)-, -CO-, -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-, -CF2-, -CF2O-, -OCF2-, -CH(alkyl)-, -CH(alkenyl)-, -CH(alkoxy)-, -CH(oxaalkyl)-, -CH=CH- or -C≡C-, but in such a way that no two O atoms are adjacent to one another and no two groups selected from -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O- and -CH=CH- are adjacent to one another,

[0120] preferably denotes alkylene having 1 to 20, preferably 1 to 12 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN,

[0121] More preferably, it represents a straight-chain ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, or a dodecylene group,

[0122] R 11 represents P,

[0123] R 21 represents P or halogen, CN, optionally fluorinated alkyl or alkenyl having up to 15 C atoms, wherein one or more non-adjacent CH2 groups may be replaced by -O-, -S-, -CO-, -C(O)O-, -OC(O)-, OC(O)-O-, preferably represents P,

[0124] P at each occurrence is each and independently of one another a polymerizable group.

[0125] The polymerizable group P is a group suitable for polymerization reactions (e.g. free radical or ionic chain polymerization, addition polymerization or condensation polymerization) or for polymer-analogous reactions (e.g. addition or condensation onto the polymer backbone). Particularly preferred are groups for chain polymerization, especially those containing a C=C double bond or a -C≡C- triple bond, and groups suitable for ring-opening polymerization (e.g. oxetane or epoxy).

[0126] Preferred groups P are selected from the group consisting of: CH2=CW 1 -CO-O-, CH2=CW 1 -CO-,

[0127]

[0128] (O) k3-、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, CH3-CH=CH-O-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, HO-CW 2 W 3 -、HS-CW 2 W 3 -、HW 2 N-、HO-CW 2 W 3 -NH-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH-, HOOC-, OCN- and W 4 W 5 W 6 Si-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular represents H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular represents H, methyl, ethyl or n-propyl, W 4 , W 5 and W 6 each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 Each independently of one another represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene which is optionally substituted by one or more groups L as defined above which are not P-Sp-, k1, k2 and k3 each independently of one another represent 0 or 1, k3 preferably represents 1, and k4 represents an integer from 1 to 10.

[0129] Particularly preferred groups P and P a,b Selected from the group consisting of: CH2=CW 1-CO-O-, especially CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, as well as CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-, and

[0130] Very particularly preferred groups P and P a,b The group consisting of an acrylate group, a methacrylate group, a fluoroacrylate group, a vinyloxy group, a chloroacrylate group, an oxetane group and an epoxy group is selected, and among these, an acrylate group or a methacrylate group is preferred.

[0131] In another preferred embodiment, the polymerizable group P represents the group

[0132]

[0133] in

[0134] Y denotes H, F, phenyl or optionally fluorinated alkyl having 1 to 12 C atoms, preferably H, methyl, ethyl, propyl, butyl,

[0135] More preferably represents H or methyl,

[0136] Especially for H,

[0137] q and r each and independently represent an integer from 0 to 8, preferably q+r≥1 and≤16, more preferably q and r each and independently represent an integer from 1 to 8, and

[0138] P represents an acrylate group or a methacrylate group,

[0139] The compounds of formula I are preferably selected from the compounds of sub-formulae I-1 to I-9.

[0140]

[0141]

[0142]

[0143] Where R 11 , R 21 , A 11 , X 11 , X 12 , Y 11 , Y 12 、Sp 11 and Sp 12 has one of the meanings given above in formula I, A 12 To A23 has one of the meanings for A, and Z 11 To Z 22 has one of the meanings as given for Z under formula I above.

[0144] Other preferred compounds of the formula I are selected from the compounds of the formulae I-1 to I-3.

[0145] Preferred compounds of formulae I-1 to I-3 are selected from compounds of formulae I-1a to I-3a:

[0146]

[0147] Where R 11 , R 21 , X 11 , X 21 、Sp 11 and Sp 21 has one of the meanings given above in formula I, Z 11 and Z 21 has one of the meanings given above for Z under formula I, and A 12 , A 21 and A 22 has one of the meanings for A, preferably A 12 , A 21 and A 22 Each and independently represents the group consisting of: 1,4-phenylene, in which one or two CH groups may be replaced by N and in which further one or more H atoms may be replaced by L as given above under formula I; or the group consisting of: trans-1,4-cyclohexylene, 1,4-cyclohexenylene, in which further one or more non-adjacent CH2 groups may be replaced by -O- and / or -S- and in which further one or more H atoms may be replaced by F.

[0148] Other preferred compounds of formula I are compounds of the following sub-formula:

[0149]

[0150] R 11 , R 21 , X 11 , X 21 、Sp 11 and Sp 21 has one of the meanings given above in formula I, Z 11 and Z 21 has one of the meanings given above for Z under formula I. In the preferred subformulae given above,

[0151] Group Each and independently is Or

[0152] as well as

[0153] wherein L is preferably F, Cl, CH3, OCH3 and COCH3 or an alkylene radical having 1 to 6 C atoms, for example methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, or X 21 -Sp 21 -R 21 .

[0154] Other preferred compounds of formula I-2a-1 are those in which Z 11 Those that represent single bonds.

[0155] Other preferred compounds of formulae I-1a-1 to I-3a-1 are those in which X 11 and X 21 Each and independently represents a single bond, -O-, -CO-O- or -O-CO-, more preferably those representing -O- or a single bond.

[0156] Other preferred compounds of formulae I-1a-1 to I-3a-1 are those in which Sp 11 and Sp 21 Each and independently represents a single bond or -(CH2) n -, wherein n is an integer between 1 and 8, more preferably between 2 and 6.

[0157] Other preferred compounds of formulae I-1a-1 to I-3a-1 are those in which R 11 and R 21 Each and independently represents an acrylate group, a methacrylate group or those of the following groups

[0158]

[0159] in

[0160] Y denotes H, F, phenyl or optionally fluorinated alkyl having 1 to 12 C atoms, preferably H, methyl, ethyl, propyl, butyl,

[0161] More preferably represents H or methyl,

[0162] Especially for H,

[0163] q and r each and independently represent an integer from 0 to 8, preferably q+r≥1 and ≤16, more preferably q and r each and independently represent an integer from 1 to 8.

[0164] Other preferred compounds of formulae I-1a-1 to I-3a-1 are those in which R 11 Those representing the following groups

[0165]

[0166] in

[0167] Y represents H or methyl,

[0168] Especially for H,

[0169] q and r each and independently represent an integer from 1 to 8, preferably 1 or 2, and

[0170] Where R 11 It represents an acrylate group or a methacrylate group.

[0171] Other preferred compounds of the formulae II-1a-1 to I-3a-1 are those in which the radical R 11 and R 21 Both refer to those of acrylate group or methacrylate group.

[0172] Preferred compounds of formula I-3a-1 are compounds of the following sub-formula:

[0173]

[0174] R 11 , R 21 , X 21 and Sp 21 has one of the meanings given above in formula I, Z 21 has one of the meanings given above under formula I for Z, r, s, t and q each and independently of one another represent an integer from 1 to 8, Y each and independently of one another represent methyl or H, and

[0175]

[0176] as well as

[0177]

[0178] wherein L is preferably F, Cl, CH3, OCH3 and COCH3 or an alkylene radical having 1 to 6 C atoms, for example methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, or X 21 -Sp 21 -R 21 .

[0179] Other preferred compounds of formula I-3a-1a are compounds of the following sub-formula:

[0180]

[0181]

[0182]

[0183] Among them, Sp 21 has one of the meanings given above in formula I, and L denotes F, Cl, OCH3 and COCH3 or alkylene having 1 to 6 C atoms, preferably denotes methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

[0184] Other preferred compounds of formula I-3a-1b are compounds of the following sub-formula:

[0185]

[0186]

[0187] Among them, Sp 21 has one of the meanings given above in formula I, and L represents F, Cl, OCH3 and COCH3 or an alkylene group having 1 to 6 C atoms, preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and s represents an integer from 1 to 8.

[0188] Other preferred compounds of formula I-3a-1c are compounds of the following sub-formula:

[0189]

[0190] wherein L represents F, Cl, OCH3 and COCH3 or an alkylene group having 1 to 6 C atoms, preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and s and t each and independently represent an integer from 1 to 8, preferably s and t are the same.

[0191] Further preferred compounds of formula I-3a-1d are compounds of the following sub-formula:

[0192]

[0193] wherein L represents F, Cl, OCH3 and COCH3 or an alkylene radical having 1 to 6 C atoms, preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl and

[0194] s and t each and independently represent an integer of 1 to 8, and preferably s and t are the same.

[0195] The compounds of formula I and its subformulae are preferably synthesized according to or analogously to the procedures described in WO 2017 / 102068 and JP 2006-6232809.

[0196] The preferred intermediate compound (5) from which the compound of formula I is synthesized can be obtained according to or in analogy to the procedures described in the following schemes:

[0197]

[0198] The compounds of formula I and its subformulae can preferably be used in mixtures comprising one or more mesogenic or liquid-crystalline compounds.

[0199] The invention therefore relates to the use of compounds of the formula I and its subformulae in liquid-crystal mixtures.

[0200] The invention further relates to liquid crystal mixtures comprising a photoalignment component A) comprising one or more photoreactive mesogens of formula I, and a liquid crystal component B), hereinafter also referred to as "LC host mixture", comprising one or more mesogenic or liquid crystal compounds.

[0201] The medium according to the invention preferably comprises 0.01% to 10%, particularly preferably 0.05% to 5% and most preferably 0.1% to 3% of component A) comprising a compound of the formula I according to the invention.

[0202] Said medium preferably comprises one, two or three, more preferably one or two and most preferably one compound of formula I according to the invention.

[0203] In a preferred embodiment, component A) consists of compounds of the formula I.

[0204] In a preferred embodiment, the LC-host mixture (component B) of the present invention comprises one or more, preferably two or more, low molecular weight (i.e. monomeric or unpolymerized) compounds which are stable or unreactive towards polymerization or photoalignment under the conditions used for polymerization of the polymerizable compounds or photoalignment of the photoreactive mesogens of formula I.

[0205] In principle, suitable host mixtures are any dielectrically negative or positive LC mixtures which are suitable for use in conventional VA, IPS or FFS displays.

[0206] Suitable LC mixtures are known to the person skilled in the art and are described in the literature.LC media with negative dielectric anisotropy for VA displays are described, for example, in EP 1 378 557 A1.

[0207] Suitable LC mixtures with positive dielectric anisotropy for LCDs and in particular for IPS displays are known, for example, from JP 07-181 439 (A), EP 0 667 555, EP 0 673 986, DE 195 09 410, DE 195 28 106, DE 19528 107, WO 96 / 23 851, WO 96 / 28 521 and WO 2012 / 079676.

[0208] Preferred embodiments of the liquid-crystalline media according to the invention having negative or positive dielectric anisotropy are indicated below and are explained in more detail with the aid of examples.

[0209] The LC host mixture is preferably a nematic LC mixture and preferably has no chiral LC phase.

[0210] In a preferred embodiment of the present invention, the LC medium contains an LC host mixture with negative dielectric anisotropy. In particular, LC media comprising a compound of formula I and an LC host mixture with negative dielectric anisotropy show superior voltage holding values ​​compared to similar compounds of formula I and LC host mixtures with negative dielectric anisotropy. Preferred embodiments of such LC media and corresponding LC host mixtures are those of the following sections a) to z):

[0211] a) LC medium comprising one or more compounds of formula CY and / or formula PY:

[0212]

[0213] in

[0214] a means 1 or 2,

[0215] b represents 0 or 1,

[0216] express

[0217] R 1 and R 2 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- in such a way that the O atoms are not directly connected to one another, preferably an alkyl radical or alkoxy radical having 1 to 6 C atoms,

[0218] Z x and Z yEach independently represents -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond, preferably a single bond,

[0219] L 1-4 Each independently represents F, Cl, OCF3, CF3, CH3, CH2F, CHF2.

[0220] Preferably, L 1 With L 2 Both mean F, or L 1 With L 2 One of them represents F and the other represents Cl, or L 3 With L 4 Both mean F or L 3 With L 4 One of represents F and the other represents Cl.

[0221] The compound of formula CY is preferably selected from the group consisting of the following sub-formulae:

[0222]

[0223]

[0224]

[0225]

[0226] wherein a represents 1 or 2, alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and alkenyl represents a straight-chain alkenyl group having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0227] The compound of formula PY is preferably selected from the group consisting of the following sub-formulae:

[0228]

[0229]

[0230]

[0231] Among them, alkyl and alkyl* Each independently of one another represents a straight-chain alkyl group having 1 to 6 C atoms, and alkenyl represents a straight-chain alkenyl group having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0232] b) LC media which additionally comprise one or more compounds of the formula:

[0233]

[0234] The various groups have the following meanings:

[0235] express

[0236]

[0237] express

[0238] R 3 and R 4 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -O-CO- or -CO-O- in such a way that the O atoms are not directly connected to one another,

[0239] Z y It represents -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond, and preferably represents a single bond.

[0240] The compound of formula ZK is preferably selected from the group consisting of the following subformulae:

[0241]

[0242]

[0243] Among them, alkyl and alkyl *Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl represents a straight-chain alkenyl radical having 2 to 6 C atoms. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0244] Particularly preferred are compounds of formulae ZK1 and ZK3.

[0245] Particularly preferred compounds of formula ZK are selected from the following subformulae:

[0246]

[0247]

[0248] Among them, propyl, butyl and pentyl are straight chain groups.

[0249] Most preferred are compounds of formula ZK1a and ZK3a.

[0250] c) LC media which additionally comprise one or more compounds of the formula:

[0251]

[0252] where the individual radicals have the following meanings on each occurrence, identically or differently:

[0253] R 5 and R 6 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- in such a way that the O atoms are not directly connected to one another, preferably an alkyl radical or alkoxy radical having 1 to 6 C atoms,

[0254] express

[0255] express And e represents 1 or 2.

[0256] The compound of formula DK is preferably selected from the group consisting of the following subformulae:

[0257]

[0258]

[0259] Among them, alkyl and alkyl* Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl represents a straight-chain alkenyl radical having 2 to 6 C atoms. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0260] d) LC media which additionally comprise one or more compounds of the formula:

[0261]

[0262] The various groups have the following meanings:

[0263] d means en means ot

[0264]

[0265] wherein at least one ring F is different from cyclohexylene,

[0266] f means 1 or 2,

[0267] R 1 and R 2 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- in such a way that the O atoms are not directly connected to one another,

[0268] Z x represents -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond, preferably a single bond,

[0269] L 1 and L 2 Each independently represents F, Cl, OCF3, CF3, CH3, CH2F, CHF2.

[0270] Preferably, the group L 1 With L 2 Both represent F, or a group L 1 With L 2 One of represents F and the other represents Cl.

[0271] The compound of formula LY is preferably selected from the group consisting of the following sub-formulae:

[0272]

[0273]

[0274]

[0275]

[0276] Where R 1 has the meaning indicated above, alkyl represents a straight-chain alkyl group having 1 to 6 C atoms, (O) represents an oxygen atom or a single bond, and v represents an integer from 1 to 6. 1 Preferably, it represents a straight-chain alkyl radical having 1 to 6 C atoms or a straight-chain alkenyl radical having 2 to 6 C atoms, in particular CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11 , CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0277] e) LC medium which additionally comprises one or more compounds selected from the group consisting of:

[0278]

[0279] Where alkyl represents C 1-6 -alkyl, L x represents H or F, and X represents F, Cl, OCF3, OCHF2 or OCH=CF2. Particularly preferred are compounds of formula G1, wherein X represents F.

[0280] f) LC medium which additionally comprises one or more compounds selected from the group consisting of:

[0281]

[0282]

[0283] Where R 5 With the above for R 1 One of the meanings indicated, alkyl means C 1-6 -alkyl, d represents 0 or 1, and z and m each independently represent an integer of 1 to 6. 5 Especially preferred is C 1-6 -alkyl or C1-6 -alkoxy or C 2-6 -alkenyl, d is preferably 1. The LC media according to the invention preferably comprise one or more compounds of the abovementioned formulae in an amount of ≥ 5% by weight.

[0284] g) LC medium which additionally comprises one or more biphenyl compounds selected from the group consisting of:

[0285]

[0286] Among them, alkyl and alkyl * each independently represents a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl radical having 2 to 6 C atoms. * Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0287] The proportion of biphenyls of the formulae B1 to B3 in the LC mixture is preferably at least 3% by weight, in particular ≥5% by weight.

[0288] Compounds of formula B2 are especially preferred.

[0289] The compounds of the formulae B1 to B3 are preferably selected from the group consisting of the following subformulae:

[0290]

[0291]

[0292] Among them, alkyl * denotes an alkyl radical having 1 to 6 C atoms. The medium according to the invention particularly preferably comprises one or more compounds of the formula B1a and / or B2e.

[0293] h) LC medium which additionally comprises one or more terphenyl compounds of the formula:

[0294]

[0295] Where R 5 and R 6 each independently of the others has one of the meanings indicated above, and

[0296]

[0297] Each independently expresses

[0298]

[0299] Where L 5 represents F or Cl, preferably F, and L 6 represents F, Cl, OCF3, CF3, CH3, CH2F or CHF2, preferably F.

[0300] The compound of formula T is preferably selected from the group consisting of the following sub-formulae:

[0301]

[0302]

[0303]

[0304] wherein R represents a straight-chain alkyl or alkoxy group having 1 to 7 C atoms, R * R represents a straight-chain alkenyl group having 2 to 7 C atoms, (O) represents an oxygen atom or a single bond, and m represents an integer of 1 to 6. * Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0305] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentoxy.

[0306] The LC media according to the invention preferably comprise from 0.5 to 30% by weight, in particular from 1 to 20% by weight, of terphenyl of the formula T and preferred subformulae thereof.

[0307] Particularly preferred are compounds of the formulae T1, T2, T3 and T21. In these compounds, R preferably represents alkyl and alkoxy, each having 1 to 5 C atoms.

[0308] Terphenyl is preferably used in the mixture according to the invention if a Δn value of ≥ 0.1 is to be achieved in the mixture. Preferred mixtures comprise 2-20% by weight of one or more terphenyl compounds of the formula T, which are preferably selected from the group of compounds T1 to T22.

[0309] i) LC medium which additionally comprises one or more compounds selected from the group consisting of:

[0310]

[0311]

[0312] Where R 1 and R 2 has the meanings indicated above and preferably each independently of one another denotes straight-chain alkyl having 1 to 6 C atoms or straight-chain alkenyl having 2 to 6 C atoms.

[0313] Preferred media comprise one or more compounds selected from the group consisting of formulae O1, O3 and O4.

[0314] k) LC medium which additionally comprises one or more compounds of the formula:

[0315]

[0316] in

[0317] express

[0318]

[0319] R 9 represents H, CH3, C2H5 or n-C3H7, (F) represents an optional fluorine substituent, and q represents 1, 2 or 3, and R 7 With R 1 In one of the indicated meanings, the amount is preferably >3% by weight, in particular ≥5% by weight and very particularly preferably 5 to 30% by weight.

[0320] Particularly preferred compounds of formula FI are selected from the group consisting of the following subformulae:

[0321]

[0322]

[0323] Where R 7 Preferably represents a straight chain alkyl group, and R 9 represents CH3, C2H5 or n-C3H7. Particularly preferred are compounds of formula FI1, FI2 and FI3.

[0324] 1) LC medium which additionally comprises one or more compounds selected from the group consisting of:

[0325]

[0326] Where R 8 With R 1 The alkyl radicals have the meanings indicated, and alkyl denotes a straight-chain alkyl radical having 1 to 6 C atoms.

[0327] m) LC media which additionally comprise one or more compounds containing tetrahydronaphthyl or naphthyl units, for example compounds selected from the group consisting of:

[0328]

[0329]

[0330] in

[0331] R 10 and R 11 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- in such a way that the O atoms are not directly connected to one another, preferably an alkyl radical or alkoxy radical having 1 to 6 C atoms,

[0332] And R 10 and R 11 preferably represents a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms or a straight-chain alkenyl radical having 2 to 6 C atoms, and

[0333] Z 1 and Z 2 Each independently represents -C2H4-, -CH=CH-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, -CH=CH-CH2CH2-, -CH2CH2CH=CH-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CF=CH-, -CH=CF-, -CH2- or a single bond.

[0334] n) LC medium which additionally comprises one or more difluorodibenzochromans and / or chromans of the following formulae:

[0335]

[0336]

[0337] in

[0338] R 11 and R 12 Each independently has the above formula N1 for R 11 One of the meanings indicated.

[0339] Ring M is trans-1,4-cyclohexylene or 1,4-phenylene,

[0340] Z mis -C2H4-, -CH2O-, -OCH2-, -CO-O- or -O-CO-,

[0341] c is 0, 1, or 2,

[0342] Preferably the amount is 3 to 20% by weight, in particular the amount is 3 to 15% by weight.

[0343] Particularly preferred compounds of formula BC, CR and RC are selected from the group consisting of the following subformulae:

[0344]

[0345]

[0346]

[0347]

[0348] Among them, alkyl and alkyl * each independently represents a straight-chain alkyl group having 1 to 6 C atoms, (O) represents an oxygen atom or a single bond, c is 1 or 2, and alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl radical having 2 to 6 C atoms. * Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0349] Very particular preference is given to mixtures comprising one, two or three compounds of the formula BC-2.

[0350] o) LC medium which additionally comprises one or more fluorinated phenanthrenes and / or dibenzofurans of the following formulae:

[0351]

[0352] Where R 11 and R 12 Each independently has the above formula N1 for R 11 One of the indicated meanings, b represents 0 or 1, L represents F, and r represents 1, 2 or 3.

[0353] Particularly preferred compounds of formula PH and BF are selected from the group consisting of the following subformulae:

[0354]

[0355]

[0356] wherein R and R′ each independently represent a straight-chain alkyl or alkoxy group having 1 to 7 C atoms.

[0357] p) LC medium which additionally comprises one or more monocyclic compounds of the formula

[0358]

[0359] in

[0360] R 1 and R 2 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- in such a way that the O atoms are not directly connected to one another, preferably an alkyl radical or alkoxy radical having 1 to 6 C atoms,

[0361] L 1 and L 2 Each independently represents F, Cl, OCF3, CF3, CH3, CH2F, CHF2.

[0362] Preferably, L 1 With L 2 Both mean F, or L 1 With L 2 One of them represents F and the other represents Cl,

[0363] The compound of formula Y is preferably selected from the group consisting of the following sub-formulae:

[0364]

[0365]

[0366] Among them, Alkyl and Alkyl * Each independently represents a straight-chain alkyl radical having 1 to 6 C atoms, Alkoxy represents a straight-chain alkoxy radical having 1 to 6 C atoms, Alkenyl and Alkenyl * Each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms, and O represents an oxygen atom or a single bond. * Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0367] Particularly preferred compounds of formula Y are selected from the group consisting of the following subformulae:

[0368]

[0369] Alkoxy here preferably denotes straight-chain alkoxy having 3, 4 or 5 C atoms.

[0370] q) LC media which, apart from the stabilizers according to the invention, in particular stabilizers of the formula I or a subformulae thereof, and comonomers, do not comprise compounds containing terminal vinyloxy groups (—O—CH═CH 2 ).

[0371] r) LC medium comprising 1 to 5, preferably 1, 2 or 3, stabilizers, preferably selected from the stabilizers according to the invention, in particular stabilizers of the formula I or a subformulae thereof.

[0372] s) LC media in which the proportion of stabilizer, in particular stabilizer of the formula I or a subformulae thereof, in the overall mixture is from 1 to 1500 ppm, preferably from 100 to 1000 ppm.

[0373] t) LC medium comprising 1 to 8, preferably 1 to 5, compounds of the formula CY1, CY2, PY1 and / or PY2. The proportion of these compounds in the overall mixture is preferably 5% to 60%, particularly preferably 10% to 35%. The content of these individual compounds is preferably 2% to 20% in each case.

[0374] u) LC medium comprising 1 to 8, preferably 1 to 5, compounds of the formula CY9, CY10, PY9 and / or PY10. The proportion of these compounds in the overall mixture is preferably 5% to 60%, particularly preferably 10% to 35%. The content of these individual compounds is preferably 2% to 20% in each case.

[0375] v) LC medium comprising 1 to 10, preferably 1 to 8, compounds of the formula ZK, in particular compounds of the formula ZK1, ZK2 and / or ZK6. The proportion of these compounds in the overall mixture is preferably 3% to 25%, particularly preferably 5% to 45%. The content of these individual compounds is preferably 2% to 20% in each case.

[0376] w) LC media in which the proportion of compounds of the formulae CY, PY and ZK in the overall mixture is greater than 70%, preferably greater than 80%.

[0377] x) LC media, wherein the LC host mixture contains one or more alkenyl-containing compounds, preferably selected from the group consisting of: formula CY, PY and LY, wherein R 1 and R2 One or both of represents a straight chain alkenyl group having 2 to 6 C atoms; Formula ZK and DK, wherein R 3 and R 4 One or both or R 5 and R 6 One or both of represents a straight-chain alkenyl group having 2 to 6 C atoms; and formulae B2 and B3; very preferably selected from formulae CY15, CY16, CY24, CY32, PY15, PY16, ZK3, ZK4, DK3, DK6, B2 and B3, most preferably selected from formulae ZK3, ZK4, B2 and B3. The concentration of these compounds in the LC host mixture is preferably 2 to 70%, very preferably 3 to 55%.

[0378] y) LC medium containing one or more, preferably 1 to 5, compounds selected from the group consisting of the formulae PY1 to PY8, very preferably the formula PY2. The proportion of these compounds in the overall mixture is preferably 1% to 30%, particularly preferably 2% to 20%. The content of these individual compounds is preferably in each case 1% to 20%.

[0379] z) LC media containing one or more, preferably 1, 2 or 3, compounds of the formula T2. The content of these compounds in the overall mixture is preferably from 1 to 20%.

[0380] In another preferred embodiment of the present invention, the LC medium contains an LC host mixture with positive dielectric anisotropy. Preferred embodiments of such LC media and corresponding LC host mixtures are those of the following parts aa) to mmm):

[0381] aa) LC medium, characterized in that it comprises one or more compounds selected from the group of compounds of formula II and formula III

[0382]

[0383] in

[0384] R 20 each identically or differently represents a halogenated or unsubstituted alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more CH2 groups in these groups may each independently of one another be substituted by -C≡C-, -CF2O-, -CH=CH-, -C≡C-, -C≡O-, -C≡ ...C-, -O-, -CO-O- or -O-CO-,

[0385] X 20 each identically or differently represents F, Cl, CN, SF5, SCN, NCS, halogenated alkyl, halogenated alkenyl, halogenated alkoxy or halogenated alkenyloxy, each having up to 6 C atoms, and

[0386] Y 20-24 each identically or differently represents H or F;

[0387] W represents H or methyl,

[0388] Each independently expresses

[0389]

[0390] The compound of formula II is preferably selected from the following formulae:

[0391]

[0392] Where R 20 and X 20 has the meaning indicated above.

[0393] R 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably X represents F. Particularly preferred are compounds of the formulae IIa and IIb, especially compounds of the formulae IIa and IIb in which X represents F.

[0394] The compound of formula III is preferably selected from the following formulae:

[0395]

[0396] Where R 20 and X 20 has the meaning indicated above.

[0397] R 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably represents F. Particularly preferred are compounds of formula IIIa and IIIe, especially compounds of formula IIIa;

[0398] bb) LC medium which additionally comprises one or more compounds selected from the following formulae:

[0399]

[0400]

[0401] in

[0402] R 20 , X 20 , W and Y 20-23 has the meaning indicated above under Formula II, and

[0403] Z 20represents -C2H4-, -(CH2)4-, -CH=CH-, -CF=CF-, -C2F4-, -CH2CF2-, -CF2CH2-, -CH2O-, -OCH2-, -COO- or -OCF2-, and also represents a single bond in Formula V and Formula VI, and also represents -CF2O- in Formula V and Formula VIII,

[0404] r represents 0 or 1, and

[0405] s represents 0 or 1;

[0406] - The compound of formula IV is preferably selected from the following formulae:

[0407]

[0408]

[0409] Where R 20 and X 20 has the meaning indicated above.

[0410] R 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably represents F or OCF3, and OCF=CF2 or Cl;

[0411] - The compound of formula V is preferably selected from the following formulae:

[0412]

[0413]

[0414] Where R 20 and X 20 has the meaning indicated above.

[0415] R 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably represents F and OCF3, as well as OCHF2, CF3, OCF=CF2 and OCH=CF2;

[0416] - The compound of formula VI is preferably selected from the following formulae:

[0417]

[0418]

[0419] Where R 20 and X 20 has the meaning indicated above.

[0420] R 20Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably represents F, as well as OCF3, CF3, CF=CF2, OCHF2 and OCH=CF2;

[0421] - The compound of formula VII is preferably selected from the following formulae:

[0422]

[0423] Where R 20 and X 20 has the meaning indicated above.

[0424] R 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably it represents F, as well as OCF3, OCHF2 and OCH=CF2.

[0425] cc) The medium further comprises one or more compounds selected from the formulae ZK1 to ZK10 given above. Particularly preferred are compounds of the formulae ZK1 and ZK3. Particularly preferred compounds of formula ZK are selected from the subformulae ZK1a, ZK1b, ZK1c, ZK3a, ZK3b, ZK3c and ZK3d.

[0426] dd) The medium additionally comprises one or more compounds selected from the group consisting of the formulae DK1 to DK12 given above. A particularly preferred compound is DK3.

[0427] ee) the medium further comprises one or more compounds selected from the following formulae:

[0428]

[0429] Where X 20 has the meaning indicated above, and

[0430] L means H or F,

[0431] "Alkenyl" means C 2-6 -alkenyl.

[0432] ff) The compounds of formula DK-3a and IX are preferably selected from the following formulae:

[0433]

[0434] Among them, "alkyl" means C 1-6 -alkyl, preferably n-C3H7, n-C4H9 or n-C5H 11 , especially n-C3H7.

[0435] gg) The medium further comprises one or more compounds selected from the formulae B1, B2 and B3 given above, preferably from the formula B2. The compounds of the formulae B1 to B3 are particularly preferably selected from the formulae B1a, B2a, B2b and B2c.

[0436] hh) the medium further comprises one or more compounds selected from the following formulae:

[0437]

[0438] Where L 20 indicates H or F, and R 21 and R 22 each identically or differently represents n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms, and preferably each identically or differently represents alkyl having 1 to 6 C atoms.

[0439] ii) the medium comprises one or more compounds of the following formulae:

[0440]

[0441]

[0442] Among them, W, R 20 , X 20 and Y 20-23 has the meaning indicated in formula III, and

[0443] Each independently expresses

[0444]

[0445] and

[0446] express

[0447]

[0448] The compounds of formula XI and XII are preferably selected from the following formulae:

[0449]

[0450]

[0451]

[0452] Where R 20 and X 20 has the meaning indicated above, and preferably R 20 represents an alkyl group having 1 to 6 C atoms, and X20 Indicates F.

[0453] The mixtures according to the invention particularly preferably comprise at least one compound of the formula XIIa and / or XIIe.

[0454] jj) The medium comprises one or more compounds of the formula T given above, which are preferably selected from the group of compounds of the formulae T21 to T23 and T25 to T27.

[0455] Particularly preferred are compounds of the formulae T21 to T23. Very particularly preferred are compounds of the following formulae:

[0456]

[0457] kk) The medium comprises one or more compounds selected from the group of formulae DK9, DK10 and DK11 given above.

[0458] 11) The medium further comprises one or more compounds selected from the following formulae:

[0459]

[0460]

[0461] Where R 20 and X 20 Each independently has one of the meanings indicated above, and Y 20-23 Each independently represents H or F. 20 Preferably it is F, Cl, CF3, OCF3 or OCHF2. 20 Preferably it denotes alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6 C atoms.

[0462] The mixtures according to the invention particularly preferably comprise one or more compounds of the formula XVIII-a,

[0463]

[0464] Where R 20 has the meaning indicated above. 20 Preferably it is straight-chain alkyl, especially ethyl, n-propyl, n-butyl and n-pentyl, and very particularly preferably n-propyl. The compounds of the formula XVIII, especially the formula XVIII-a, are preferably used in the mixture according to the invention in an amount of 0.5 to 20% by weight, particularly preferably 1 to 15% by weight.

[0465] mm) the medium further comprises one or more compounds of the formula XIX,

[0466]

[0467] Where R 20 , X 20 and Y 20-25 has the meaning indicated in formula I, s represents 0 or 1, and

[0468]

[0469] express

[0470] In Formula XIX, X 20 It may also represent an alkyl radical having 1 to 6 C atoms or an alkoxy radical having 1 to 6 C atoms. The alkyl or alkoxy radical is preferably straight-chain.

[0471] R 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably F;

[0472] - The compound of formula XIX is preferably selected from the following formulae:

[0473]

[0474]

[0475] Where R 20 , X 20 and Y 20 has the meaning indicated above. 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably, F is represented, and Y 20 Preferably F;

[0476] i preferred sp select ref is er

[0477]

[0478] -R 20 is a straight-chain alkyl or alkenyl group having 2 to 6 C atoms;

[0479] nn) the medium comprises one or more compounds of the formulae G1 to G4 given above, which are preferably selected from G1 and G2, wherein alkyl represents C 1-6 -alkyl, L x represents H, and X represents F or Cl. In G2, X particularly preferably represents Cl.

[0480] oo) the medium comprises one or more compounds of the following formulae:

[0481]

[0482]

[0483] Where R 20 and X 20 has the meaning indicated above. 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably represents F. The medium according to the invention particularly preferably comprises one or more compounds of the formula XXII, in which X 20 Preferably it represents F. The compounds of the formulae XX-XXII are preferably used in the mixtures according to the invention in an amount of 1 to 20% by weight, particularly preferably 1 to 15% by weight. Particularly preferably, the mixture comprises at least one compound of the formula XXII.

[0484] pp) the medium comprises one or more compounds of the following formulae:

[0485]

[0486] Where R 20 and X 20 has the meaning indicated above. 20 Preferably, X represents an alkyl radical having 1 to 6 C atoms. 20 Preferably represents F. The medium according to the invention particularly preferably comprises one or more compounds of the formula M-1, in which X 20 Preferably it represents F. The compounds of the formulae M-1 to M-3 are preferably used in the mixtures according to the invention in an amount of 1 to 20% by weight, particularly preferably 1 to 15% by weight.

[0487] Other preferred embodiments are indicated below:

[0488] qq) the medium comprises two or more compounds of formula XII, in particular compounds of formula XIIe;

[0489] rr) the medium contains 2 to 30% by weight, preferably 3 to 20% by weight, particularly preferably 3 to 15% by weight, of a compound of the formula XII;

[0490] ss) the medium comprises, in addition to the compound of formula XII, a further compound selected from the group of compounds of formulae II, III, IX-XIII, XVII and XVIII;

[0491] tt) the proportion of the compounds of formula II, III, IX-XI, XIII, XVII and XVIII in the overall mixture is 40% to 95% by weight;

[0492] uu) the medium contains 10 to 50% by weight, particularly preferably 12 to 40% by weight, of a compound of the formula II and / or formula III;

[0493] vv) the medium contains 20 to 70% by weight, particularly preferably 25 to 65% by weight, of a compound of the formula IX to XIII;

[0494] ww) the medium contains 4 to 30% by weight, particularly preferably 5 to 20% by weight, of a compound of the formula XVII;

[0495] xx) the medium contains 1 to 20% by weight, particularly preferably 2 to 15% by weight, of a compound of the formula XVIII;

[0496] yy) the medium comprises at least two compounds of the following formulae:

[0497]

[0498] zz) the medium comprises at least two compounds of the following formulae:

[0499]

[0500]

[0501] aaa) The medium comprises at least two compounds of the formula XIIa and at least two compounds of the formula XIIe.

[0502] bbb) medium comprises at least one compound of the formula XIIa and at least one compound of the formula XIIe and at least one compound of the formula IIIa.

[0503] ccc) medium comprises at least two compounds of the formula XIIa and at least two compounds of the formula XIIe and at least one compound of the formula IIIa.

[0504] ddd) medium comprises in total ≥ 25% by weight, preferably ≥ 30% by weight, of one or more compounds of the formula XII.

[0505] eee) the medium contains ≥20% by weight, preferably ≥24% by weight, preferably 25 to 60% by weight, of a compound of the formula ZK3, in particular a compound of the formula ZK3a,

[0506]

[0507] fff) The medium comprises at least one compound selected from the group consisting of compounds ZK3a, ZK3b and ZK3c, preferably a combination of ZK3a and compound ZK3d

[0508]

[0509] ggg) medium comprises at least one compound of formula DPGU-nF.

[0510] hhh) The medium comprises at least one compound of the formula CDUQU-nF.

[0511] iii) the medium comprises at least one compound of formula CPU-n-OXF.

[0512] jjj) The medium comprises at least one compound of formula CPGU-3-OT.

[0513] kkk) The medium comprises at least one compound of formula PPGU-nF.

[0514] 111) The medium comprises at least one compound of the formula PGP-nm, preferably two or three compounds.

[0515] mmm) medium comprises at least one compound of the formula PGP-2-2V having the structure

[0516]

[0517] In a preferred embodiment, the liquid-crystal mixtures according to the invention further comprise a polymerizable component C) which comprises one or more polymerizable compounds.

[0518] The polymerizable compound may be selected from isotropic or mesogenic polymerizable compounds known to those skilled in the art.

[0519] Preferably, the polymerizable component C) comprises one or more polymerizable compounds of formula P,

[0520] P a -(Sp a ) s1 -A 2 -(Z a -A 1 ) n2 -(Sp b ) s2 -P b P

[0521] The various groups have the following meanings:

[0522] P a , P b each independently of one another represents a polymerizable group,

[0523] Sp a 、Sp b represents a spacer group identically or differently on each occurrence,

[0524] s1 and s2 are each independently 0 or 1.

[0525] A 1 , A 2Each independently represents a group selected from the following groups:

[0526] a) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene and 4,4'-dicyclohexylene, in which one or more non-adjacent CH2 groups may be replaced by -O- and / or -S-, and in which one or more H atoms may be replaced by F,

[0527] b) the group consisting of 1,4-phenylene and 1,3-phenylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L,

[0528] c) the group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L,

[0529] d) the group consisting of saturated, partially unsaturated or fully unsaturated and optionally substituted polycyclic radicals having 5 to 20 ring C atoms, one or more of which may additionally be replaced by heteroatoms, which are preferably selected from the group consisting of:

[0530]

[0531] Furthermore, one or more H atoms in these groups may be replaced by L, and / or one or more double bonds may be replaced by single bonds, and / or one or more CH groups may be replaced by N,

[0532] n2 represents 0, 1, 2 or 3,

[0533] Z a In each case, independently of one another, it represents -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n -(wherein n is 2, 3 or 4), -O-, -CO-, -C(R y R z )-, -CH2CF2-, -CF2CF2- or a single bond,

[0534] L, identically or differently on each occurrence, represents F, Cl, CN, SCN, SF5 or linear or branched, in each case optionally fluorinated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms,

[0535] R y , R zeach independently of one another represents H, F or a straight-chain or branched alkyl radical having 1 to 12 C atoms, wherein moreover one or more H atoms may be replaced by F,

[0536] M represents -O-, -S-, -CH2-, -CHY 1 -or-CY 1 Y 2 -,and

[0537] Y 1 and Y 2 Each independently has the above for R y One of the indicated meanings may represent Cl or CN.

[0538] Preferred spacer groups Sp a,b is selected from the formula Sp"-X", so that the group P-Sp- and P a / b -Sp a / b - respectively conform to the formula P-Sp"-X"- and P a / b -Sp"-X"-, where

[0539] Sp" denotes an alkylene radical having 1 to 20, preferably 1 to 12 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN and in which one or more non-adjacent CH2 groups may each independently of one another be substituted by -O-, -S-, -NH-, -N(R)-, -S-, -NH-, -NH- or -N(R)- in such a way that the O and / or S atoms are not directly connected to one another. 0 )-、-Si(R 00 R 000 )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R 00 )-CO-O-、-O-CO-N(R 00 )-、-N(R 00 )-CO-N(R 00 )-, -CH=CH- or -C≡C-,

[0540] X" means -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R 00 )-、-N(R 00 )-CO-、-N(R 00 )-CO-N(R 00 )-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 0-、-CY 3 =CY 4 -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond,

[0541] R 0 , R 00 and R 000 each independently of one another represents H or an alkyl group having 1 to 12 C atoms, and

[0542] Y 3 and Y 4 Each of them, identically or differently, represents H, F, Cl or CN.

[0543] X" is preferably -O-, -S-, -CO-, -C(O)O-, -OC(O)-, -OC(O)O-, -CO-NR 0 -、-NR 0 -CO-、-NR 0 -CO-NR 0 - or single key.

[0544] A typical spacer group Sp" is, for example, -(CH2) p1 -、-(CH2CH2O) q1 -CH2CH2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR 00 R 000 -O) p1 -, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 00 and R 000 has the meaning indicated above.

[0545] A particularly preferred group -Sp"-X"- is -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -O-CO-O-, wherein p1 and q1 have the meanings indicated above.

[0546] Particularly preferred radicals Sp" are, for example, in each case straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, vinylene, propenylene and butenylene.

[0547] Particularly preferred monomers of formula P are the following:

[0548]

[0549]

[0550]

[0551]

[0552] The various groups have the following meanings:

[0553] P 1 To P 3 each independently of one another represents a polymerizable group as defined for formula P, preferably represents an acrylate group, a methacrylate group, a fluoroacrylate group, an oxetane group, a vinyloxy group or an epoxy group,

[0554] Sp 1 To Sp 3 Each independently of one another represents a single bond or a spacer group, which preferably has the a One of the indicated meanings, and particularly preferably represents -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -CO-O- or -(CH2) p1 -O-CO-O-, where p1 is an integer from 1 to 12 and where in the last-mentioned radical the connection to the adjacent ring is via an O atom,

[0555] In addition, the group P 1 -Sp 1 -、P 2 -Sp 2 - and P 3 -Sp 3 - may represent a group R aa , provided that the groups P 1 -Sp 1 -、P 2 -Sp 2 - and P 3 -Sp 3 -At least one of them does not represent R aa ,

[0556] R aa represents H, F, Cl, CN or a straight-chain or branched alkyl group having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups may each independently be connected to each other via C(R) in such a way that the O and / or S atoms are not directly connected to each other.0 )=C(R 00 )-、-C≡C-、-N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, and one or more H atoms may be replaced by F, Cl, CN or P 1 -Sp 1 - replaces, particularly preferably, straight-chain or branched, optionally monofluorinated or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl or alkylcarbonyloxy having 1 to 12 C atoms, wherein the alkenyl and alkynyl have at least two C atoms and the branched radicals have at least three C atoms,

[0557] R 0 , R 00 each independently of one another represents H or an alkyl radical having 1 to 12 C atoms,

[0558] R y and R z each independently represents H, F, CH3 or CF3,

[0559] Z p1 Indicates -O-, -CO-, -C(R y R z )- or -CF2CF2-,

[0560] Z p2 and Z p3 Each independently represents -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n3 -, where n3 is 2, 3 or 4,

[0561] L, identically or differently on each occurrence, represents F, Cl, CN, SCN, SF5 or linear or branched, optionally monofluorinated or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, preferably represents F,

[0562] L' and L" each independently represent H, F or Cl,

[0563] r represents 0, 1, 2, 3 or 4,

[0564] s represents 0, 1, 2, or 3,

[0565] t represents 0, 1, or 2, and

[0566] x represents 0 or 1.

[0567] In a particularly preferred embodiment of the present invention, the LC mixture or component C) comprises one or more compounds of the formula P10-1.

[0568]

[0569] Wherein the parameters are defined as described above, and P 1 and P 2 Preferably it denotes acrylate or methacrylate.

[0570] Particularly preferred compounds of formula P10-1 are selected from the group consisting of

[0571]

[0572] Each n4 independently represents an integer between 2 and 10, preferably 3, 4, 5 or 6.

[0573] The polymerizable compounds of the formula I and P are also suitable for polymerization without initiators, which is accompanied by a number of advantages, such as lower material costs and, in particular, reduced contamination of the LC medium by possible residual amounts of initiators or their degradation products. The polymerization can therefore also be carried out without the addition of initiators. Therefore, in a preferred embodiment, the LC medium does not contain a polymerization initiator.

[0574] The polymerizable component C) or the LC medium as a whole may also comprise one or more stabilizers to prevent undesired spontaneous polymerization of the RM, for example during storage or transport. Suitable types and amounts of stabilizers are known to the person skilled in the art and are described in the literature. Particularly suitable are stabilizers, for example from Commercially available stabilizers of the TUNA series (BASF SE), for example 1076. If a stabilizer is used, its proportion is preferably 10 ppm to 10,000 ppm, particularly preferably 50 ppm to 1000 ppm, based on the total amount of RM or polymerizable components.

[0575] The medium according to the invention preferably comprises 0.01% to 10%, particularly preferably 0.05% to 7.5% and most preferably 0.1% to 5% of a compound of component C) comprising a compound of the formula P according to the invention. The medium preferably comprises one, two or three, more preferably one or two and most preferably one compound of the formula P according to the invention.

[0576] With the aid of suitable additives, the liquid crystal phases according to the invention can be modified so that they can be used in all types of liquid crystal display devices disclosed to date. Additives of this type are known to the person skilled in the art and are described in detail in the literature (H. Kelker / R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980). For example, polychromatic dyes can be added for the production of colored guest-host systems or substances can be added to modify the dielectric anisotropy, the viscosity and / or the alignment of the nematic phase.

[0577] The media according to the invention are prepared in a manner conventional per se. In general, the components are dissolved in one another, preferably at elevated temperatures.

[0578] The present invention therefore further relates to a process for producing the LC media according to the invention, comprising the step of mixing one or more compounds of the formula I with a liquid-crystalline component B) comprising one or more mesogenic or liquid-crystalline compounds as set out above.

[0579] The present invention further relates to a method for manufacturing a liquid crystal display, comprising at least the following steps:

[0580] Providing a first substrate, which includes a pixel electrode and a common electrode, wherein the electrodes are used to generate an electric field substantially parallel to a surface of the first substrate in a pixel region;

[0581] Providing a second substrate, the second substrate being arranged opposite to the first substrate;

[0582] inserting a liquid crystal mixture between the first substrate and the second substrate, the liquid crystal mixture comprising one or more compounds of formula I, component B) and optionally component C);

[0583] irradiating the liquid crystal mixture with linearly polarized light to induce photo-alignment of the liquid crystal;

[0584] The polymerizable compound of the liquid crystal mixture is cured by irradiation with ultraviolet light or visible light having a wavelength of 450 nm or less.

[0585] The invention further relates to the use of the liquid-crystal mixtures according to the invention for producing liquid-crystal displays.

[0586] The invention further relates to a liquid crystal display manufactured by the method set out above.

[0587] Hereinafter, the production method of the present invention is explained in more detail.

[0588] The first substrate comprises a pixel electrode and a common electrode for generating an electric field substantially parallel to the surface of the first substrate in the pixel area. The skilled person is aware of different kinds of displays having at least two electrodes on one substrate, the most notable difference being whether both the pixel electrode and the common electrode are structured (as is typical for IPS displays) or whether only the pixel electrode is structured and the common electrode is not structured (as is the case for FFS displays).

[0589] It has to be understood that the invention relates to any kind of electrode configuration suitable for generating an electric field substantially parallel to the first substrate surface in the pixel area; mentioned above, ie IPS as well as FFS displays.

[0590] The method according to the invention is independent of the type of substrate or surface material with which the liquid crystal mixture according to the invention is contacted during and after the method. Examples of materials for substrates or surfaces include polyimide, indium tin oxide (ITO), indium zinc oxide (IZO), silicon nitride (SiN x ) and an organic polymer of silicon dioxide (SiO2). The method is particularly suitable for use in displays containing substrates that do not have a polyimide layer on one or more of the surfaces in contact with the liquid crystal.

[0591] Where one or more of the substrates contains a polyimide layer, then the polyimide may be rubbed or unrubbed, preferably unrubbed.

[0592] The present invention therefore relates to a display produced by the process according to the invention, wherein the substrate comprises a rubbed or unrubbed polyimide layer, preferably an unrubbed polyimide layer.

[0593] The invention further relates to a display produced by the method according to the invention, wherein neither or only one of the top and bottom substrates contains a polyimide layer.

[0594] In one embodiment of the present invention, the liquid crystal composition is injected between the first and second substrates or filled into the box by capillary force after the first and second substrates are combined. In an alternative embodiment, the liquid crystal composition can be inserted between the first and second substrates by combining the second substrate to the first substrate after the liquid crystal composition is loaded on the first substrate. Preferably, the liquid crystal is dispensed dropwise onto the first substrate by a method called "one drop filling" (ODF) method, such as described in JPS63-179323 and JPH10-239694, or by using an inkjet printing (IJP) method.

[0595] In a preferred embodiment, the method according to the invention contains a method step in which the liquid crystal inside the display panel is left to rest for a period of time in order to uniformly redistribute the liquid crystal medium inside the panel (referred to herein as "annealing").

[0596] However, it is also preferred to combine the annealing step with a previous step, such as edge sealant pre-curing. In this case, a "separate" annealing step may not be required at all.

[0597] For the production of the display of the present invention, the photoreactive mesogens of formula I are preferably redistributed in the panel. After filling and assembly, the display panel is annealed for a time between 1 min and 3 h, preferably between 2 min and 1 h and most preferably between 5 min and 30 min. Annealing is preferably carried out at room temperature.

[0598] In alternative embodiments, annealing is performed at elevated temperature, preferably above 20°C and below 140°C, more preferably above 40°C and below 100°C and most preferably above 50°C and below 80°C.

[0599] In a preferred embodiment, one or more of the method steps of filling the display, annealing, photoaligning and curing the polymerizable compound are carried out at a temperature above the clearing point of the liquid crystal host mixture.

[0600] During photo-alignment of the liquid crystal inside the liquid crystal panel, anisotropy is induced by exposing the display or the liquid crystal layer to linearly polarized light.

[0601] In a preferred embodiment of the invention, the photoreactive component A) comprising one or more compounds of the formula I is photoaligned in a first step using linearly polarized light and further cured in a second step using linearly polarized or unpolarized UV light. In the second step, the optional component C) is also further cured.

[0602] In another preferred embodiment, the linearly polarized light applied according to the process of the invention is UV light, which enables simultaneous photoalignment and photocuring of the photoreactive component A) comprising one or more compounds of the formula I and, if present, of the polymerizable component C).

[0603] Photoalignment of the photoreactive compound of formula I and curing of the polymerizable groups of the compound of formula I and of the optional polymerizable compound of formula P can be carried out simultaneously or stepwise. In case the method is divided into different steps, the individual steps can be carried out at the same temperature or at different temperatures.

[0604] After the photoalignment and curing steps, a so-called "post-curing" step may optionally be carried out at reduced temperature by irradiation with UV light and / or visible light (both linear or unpolarized) to remove unreacted polymerizable compounds. Post-curing is preferably carried out at above 0° C. and below the clearing point of the LC mixture utilized, preferably at 20° C. and below 60° C. and most preferably at above 20° C. and below 40° C.

[0605] The polymerizable compound is polymerized or crosslinked (if the polymerizable compound contains two or more polymerizable groups), optionally under application of an electric field. The polymerization can be carried out in one or more steps.

[0606] Suitable and preferred polymerization methods for component C) are, for example, thermal polymerization or photopolymerization, preferably photopolymerization, in particular UV photopolymerization. Optionally, one or more initiators may also be added here. Suitable conditions for the polymerization and suitable types and amounts of initiators are known to the person skilled in the art and are described in the literature. Suitable for free-radical polymerization are, for example, commercially available photoinitiators or (BASF SE). If an initiator is used, its proportion is preferably from 0.001% to 5% by weight, particularly preferably from 0.001% to 1% by weight.

[0607] The invention furthermore relates to an electro-optical liquid crystal display component comprising a liquid crystal medium according to the invention, which is preferably homogeneously aligned.In a preferred embodiment, the liquid crystal display has IPS or FFS mode.

[0608] Further combinations of embodiments and variants of the invention according to the present description result from the claims.

[0609] The present invention is explained in more detail below with reference to working examples, but is not intended to be limited thereto. A person skilled in the art will be able to gather working details not given in detail in the general description from the working examples, generalize the working details according to general expert knowledge and apply them to specific problems.

[0610] In addition to common and familiar abbreviations, the following abbreviations are used:

[0611] C: crystalline phase; N: nematic phase; Sm: smectic phase; I: isotropic phase. The numbers between these symbols show the transition temperatures of the substances involved.

[0612] Unless otherwise indicated, temperature data are in °C.

[0613] The physical, physicochemical or electro-optical parameters are determined by generally known methods, such as, inter alia, the manual "Merck Liquid Crystals - -Physical Properties of Liquid Crystals -Description of the Measurement Methods", 1998, Merck KGaA, Darmstadt.

[0614] In the above and below, Δn represents optical anisotropy (589 nm, 20° C.) and Δε represents dielectric anisotropy (1 kHz, 20° C.). The dielectric anisotropy Δε is measured at 20° C. and 1 kHz. The optical anisotropy Δn is measured at 20° C. and a wavelength of 589.3 nm.

[0615] The Δε and Δn values ​​and the rotational viscosity (γ1) of the compounds according to the invention are obtained by linear extrapolation from liquid crystal mixtures consisting of 5% to 10% of the respective compound according to the invention and 90% to 95% of the commercially available liquid crystal mixtures ZLI-2857 (for Δε) or ZLI-4792 (for Δn, γ1) (mixtures, Merck KGaA, Darmstadt).

[0616] The compounds used in the present invention are prepared by methods known per se, as described in the literature (e.g. in standard works, such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), specifically under reaction conditions known and suitable for the reaction. Variants known per se can also be used here, which are not mentioned in more detail here.

[0617] In the present invention and in particular in the following examples, the structures of the mesogenic compounds are indicated by means of abbreviations (also called acronyms). In these acronyms, the chemical formulae are abbreviated as follows using the following Tables A to C. All groups C n H 2n+1 , C m H 2m+1 and C l H 2l+1 or C n H 2n-1 , C m H 2m-1 and C l H 2l-1= represents a straight chain alkyl or alkenyl, preferably 1E-alkenyl, each of which has n, m and 1 C atoms, respectively. Table A lists the codes for the ring elements of the core structure of the compound, while Table B shows the linking groups. Table C gives the meaning of the codes for the left-hand or right-hand terminal groups. The acronyms consist of the code for the ring element with the optional linking group, followed by the first hyphen and the code for the left-hand terminal group and the second hyphen and the code for the right-hand terminal group. Table D shows the illustrative structures of the compounds and their corresponding abbreviations.

[0618] Table A: Ring elements

[0619]

[0620]

[0621]

[0622] Table B: Linking Groups

[0623]

[0624] Table C: Terminal Groups

[0625] Use with each other or other

[0626]

[0627] where n and m each represent an integer, and the three dots "..." are placeholders for other abbreviations from this table.

[0628] The following table shows illustrative structures and their corresponding abbreviations. These are shown to illustrate the meaning of the abbreviation conventions. In addition, they represent compounds that are preferably used.

[0629] Table D: Illustrative structure

[0630]

[0631]

[0632]

[0633]

[0634]

[0635]

[0636]

[0637]

[0638]

[0639]

[0640]

[0641]

[0642]

[0643]

[0644]

[0645]

[0646]

[0647]

[0648]

[0649]

[0650]

[0651] Here, n, m and l preferably represent 1 to 7 independently of one another.

[0652] The following table (Table E) shows illustrative compounds that can be used as additional stabilizers in the mesogenic media of the present invention.

[0653] Table E

[0654] Table E shows possible stabilizers which can be added to the LC media of the present invention.

[0655] (here n represents an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and the terminal methyl group is not shown).

[0656]

[0657]

[0658]

[0659]

[0660]

[0661]

[0662] The LC medium preferably comprises 0% to 10% by weight, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight, of stabilizer.

[0663] Table F below shows illustrative compounds that may be preferably used as chiral dopants in the mesogenic media of the present invention.

[0664] Table F

[0665]

[0666]

[0667]

[0668]

[0669] In a preferred embodiment of the present invention, the mesogenic medium comprises one or more compounds selected from the group of Table F compounds.

[0670] The mesogenic medium according to the present application preferably comprises two or more, preferably four or more, compounds selected from the group consisting of the compounds of the above tables.

[0671] The liquid-crystalline media according to the invention preferably comprise

[0672] 7 or more, preferably 8 or more, individual compounds having preferably 3 or more, particularly preferably 4 or more different formulae selected from the group of compounds of Table D.

[0673] Hereinafter, the present invention will be described in more detail and specifically with reference to Examples, which however are not intended to limit the present invention. Example

[0674] Compound Examples

[0675] 1.1. Synthesis of TIPS-protected (E)-3-[4-(6-hydroxyhexyloxy)-1-naphthyl]prop-2-enoic acid 5

[0676]

[0677] 25 g (97%, 109 mmol) of 4-bromonaphthalene-1-ol 1, 41 g (91%, 109 mmol) of TIPS-protected 6-bromohexan-1-ol 2 were dissolved in 200 ml of DMF. 19 g (130 mmol) of potassium carbonate were added and the mixture was stirred at 80° C. for 16 hours. The cooled mixture was filtered. The filtrate was poured into 0° C. cold water and diluted with MTB-ether. The organic layer was dried over sodium sulfate and the solvent was evaporated. The residue was purified by silica gel chromatography (n-heptane / toluene 9 / 1). Yield: 43 g (99%) and the corresponding TIPS-protected 1-bromo-4-heptyloxy-naphthalene 3 was obtained as a colorless solid.

[0678] 5 g (10 mmol) of TIPS protected 1-bromo-4-heptyloxy-naphthalene 3, 1.2 ml (11 mmol) of ethyl acrylate and 3 ml (21 mmol) of triethylamine were dissolved in 40 ml of acetonitrile, treated with 70 mg (0.3 mmol) of palladium(II) acetate and 160 mg (0.5 mmol) of tri(o-tolyl)-phosphine and heated to reflux for 15 min. The cooled mixture was diluted with water and MTB-ether was added. The organic layer was dried over sodium sulfate and the solvent was evaporated. The residue was purified by silica gel chromatography (n-heptane / toluene 1 / 1->toluene; chlorobutane) and TIPS protected (E)-3-[4-(6-hydroxyhexyloxy)-1-naphthyl]prop-2-enoic acid ethyl ester 4 was obtained as a slightly yellow oil.

[0679] 3.1 g (6 mmol) of the ester TIPS-protected (E)-3-[4-(6-hydroxyhexyloxy)-1-naphthyl]prop-2-enoic acid ethyl ester 4 was dissolved in 3 ml MeOH and 20 ml THF, treated with 7 ml 2N caustic and stirred at 40° C. for 15 hours. The mixture was poured into 300 ml saturated ammonium chloride, diluted with MTB-ether and adjusted to pH 3 using 1N hydrochloric acid. The organic layer was dried over sodium sulfate and the solvent was evaporated. The residue was treated with boiling acetonitrile. The solid was isolated and TIPS-protected (E)-3-[4-(6-hydroxyhexyloxy)-1-naphthyl]prop-2-enoic acid 5 was obtained.

[0680] 1.2. Synthesis of THP-protected (E)-3-[4-(6-hydroxyhexyloxy)-1-naphthyl]prop-2-enoic acid 8

[0681]

[0682] 15 g (95%, 64 mmol) of 1 and 2.4 g of pyridinium toluene-4-sulfonate (10 mmol) were suspended in 40 ml of DCM, treated with 11 ml (128 mmol) of THP dissolved in 20 ml of DCM and stirred overnight at room temperature. The mixture was diluted with water and the aqueous layer was extracted with DCM. The combined organic layers were dried over sodium sulfate and filtered through silica gel (DCM) to give 6 as a slightly yellow oil.

[0683] A mixture of 18.8 g (90%, 55 mmol) of bromide 6, 7.8 ml (55 mmol) of butyl acrylate, 11 ml (79 mmol) of triethylamine and 190 ml of acetonitrile is treated with 350 mg (1.6 mmol) of palladium(II) acetate and 800 mg (2.6 mmol) of tri(o-tolyl)-phosphine and heated to reflux for 4 hours. The cooled mixture is diluted with water and MTB-ether. The organic layer is dried over sodium sulfate and the solvent is evaporated. The residue is purified by silica gel chromatography (chlorobutane) and 7 is obtained as a yellow solid.

[0684] 16.4 g (92%, 43 mmol) of ester 7 were dissolved in 20 ml MeOH and 130 ml THF, treated with 43 ml 2N caustic and stirred at 30°C for 5 hours. The mixture was poured into 1000 ml saturated ammonium chloride, diluted with MTB-ether and adjusted to pH 4.5 using 1N hydrochloric acid. The organic layer was dried over sodium sulfate and the solvent was evaporated. The residue was treated twice with DCM and the DCM was evaporated. The residue was treated with acetonitrile and cooled to 6°C. The solid was isolated and 8 was obtained.

[0685] 1.3. Synthesis of 1-[4-(Benzyloxy)-3-methylphenyl]ethan-1-one 9

[0686]

[0687] 12.7 g (85.0 mmol) 1-(4-hydroxy-3-methyl-phenyl)-ethanone, 12.7 mL (107 mmol) benzyl bromide and 7.62 g (55.0 mmol) potassium carbonate were dissolved / suspended in methyl (ethyl) ketone and stirred under reflux for 18 hours. The reaction mixture was cooled to room temperature (RT) and the precipitated solid was filtered and washed with methyl tert-butyl ether (MTB-E). The product was further crystallized from heptane at 5° C. and used directly in the next synthesis step.

[0688] 1.4 Synthesis of 4-(Benzyloxy)-3-methylphenyl acetate 10

[0689]

[0690] 39.1 mL (0.165 mmol) of m-chloroperbenzoic acid was suspended in 102 mL of dichloromethane and a solution of 19.3 g (80.0 mmol) of ketone 9 in 72 mL of dichloromethane was added dropwise to the reaction mixture. The yellow reaction mixture was then gradually heated to reflux and stirred for 16 hours. The reaction mixture was cooled to room temperature (RT) and poured into ice water. The organic layer was filtered off from the precipitated 3-chlorobenzoic acid, washed with sodium bicarbonate, tested for peroxide residues (with iron (II) sulfate ammonia solution), dried over sodium sulfate, filtered and evaporated under vacuum. The crude product was filtered through 900 g of silica gel using toluene and ethyl acetate (95:5) to obtain the product as a yellow oil.

[0691] 1.5. Synthesis of 4-(Benzyloxy)-3-methylphenol 11

[0692]

[0693] 23.4 g (91.0 mmol) of acetate 10 are dissolved in 181.0 mL of ethanol and 5.84 mL (197.0 mmol) of sodium hydroxide solution (32%) are added dropwise to the solution (the reaction solution turns red). The reaction mixture is stirred at ambient temperature for 2 hours and then poured into ice water and treated with HCl solution until a pH value of 1 is reached. The reaction mixture is extracted with methyl tert-butyl ether (MTB-E), the organic layer is dried over sodium sulfate, filtered and evaporated under vacuum. The black oil is filtered through silica gel with dichloromethane and the solid obtained is then crystallized from heptane at -25°C to give light brown crystals.

[0694] 1 H NMR (500MHz, DMSO-d6) δ=2.13ppm(s,3H,CH3),4.99(s,2H,CH2-O),6.51(dd,J=2.86,8.62Hz,1H),6.58(d,J= 2.49Hz, 1H), 6.81 (d, J = 8.70Hz, 1H), 7.32 (d, J = 7.23Hz, 1H), 7.39 (t, J = 7.71Hz, 2H), 7.44 (d, J = 8.70Hz, 2H).

[0695] 1.6. Synthesis of 4-triisopropylsilyloxybenzoic acid (4-benzyloxy-3-methyl-phenyl ester) (12)

[0696]

[0697] A solution of 21.1 g (98 mmol) of 11 and 29 g (98 mmol) of 4-triisopropylsilyloxybenzoic acid in 900 ml of dichloromethane was treated with 600 mg of DMAP and 22.6 g (118 mmol) of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and stirred overnight at room temperature. The mixture was filtered through silica gel (dichloromethane). The solvent of the product-containing fractions was evaporated to give 12.

[0698] 1.8. Synthesis of 4-triisopropylsilyloxybenzoic acid (4-hydroxy-3-methyl-phenyl ester) (13)

[0699]

[0700] A solution of 35 g (71 mmol) of 12 in 350 ml of THF was hydrogenated with Pd-C-5% (51.4% water) at room temperature. The solvent was evaporated to give 13.

[0701] 1.9. Synthesis of methyl 4-[(6-hydroxyhexyl)oxy]benzoate 14

[0702]

[0703] 40.0 g (263 mmol) of methyl 4-hydroxybenzoate and 43.6 g (315 mmol) were dissolved in 150 mL of methyl (ethyl) ketone and 49.9 g (276 mmol) of 6-bromohexan-1-ol were added and the reaction mixture was heated to reflux and stirred for 16 hours. The reaction mixture was then cooled to room temperature (RT) and the precipitated residue was filtered off, washed with acetone and dried under vacuum. The crude product was crystallized from toluene at 5° C. and the product was used in the next step without further purification.

[0704] 1.10. Synthesis of methyl 4-[(6-{[tri(propyl-2-yl)silyl]oxy}hexyl)oxy]benzoate 15

[0705]

[0706] 18.8 g (74.51 mmol) of ester 14 and 0.45 g (3.73 mmol) of 4-dimethylaminopyridine were dissolved in 90 mL of N,N-dimethylformamide (DMF). 15.8 g (81.96 mmol) of chloro-triisopropylsilane (dissolved in 30 mL of DMF) was added dropwise to the reaction mixture at room temperature and stirred for 16 hours. The reaction mixture was diluted with methyl tert-butyl ether (MTB-E) and poured into ice water. The organic layer was dried over sodium sulfate, filtered and evaporated under vacuum to give the product as an oil, which was further purified by column chromatography using silica gel and chlorobutane as solvent. The product was a light yellow oil.

[0707] 1.11. Synthesis of 4-[(6-{[tri(propyl-2-yl)silyl]oxy}hexyl)oxy]benzoic acid 16

[0708]

[0709] 27.0 g (66.0 mmol) of ester 15 was dissolved in a mixture of 160 mL of methanol and 80 mL of tetrahydrofuran and 90 mL of NaOH (2N). The reaction mixture was stirred at 40° C. for 2 hours. The reaction mixture was cooled to room temperature (RT), carefully poured into ice water, neutralized with HCl (2N) and extracted with ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated under vacuum to give the product as a white solid, which was purified by crystallization from ethyl acetate at 3° C. to give a white crystalline solid.

[0710] 1 H NMR(500MHz,DMSO-d6)δ=1.02ppm(m c ,21H,Si-(C3H7)3),1.34-1.47(m,4H,CH2),1.51(quint,J=6.57Hz,2H,CH2),1.73(quint,J=6.01Hz,2H,C H2), 3.69 (t, J = 6.33Hz, 2H, CH2), 4.02 (t, J = 6.45Hz, 2H, CH2), 6.98 (d, J = 8.91Hz, 2H), 7.87 (J = 8.89Hz, 2H).

[0711] 1.12. Synthesis of 4-(benzyloxy)-3-methylphenyl 4-[(6-{[tri(propyl-2-yl)silyl]oxy}hexyl)oxy]benzoate 17

[0712]

[0713] 28.0 g (70.7 mmol) of acid 16, 15.5 g (72.18 mmol) of phenol 11 and 1.72 g (14.15 mmol) of 4-dimethylaminopyridine were dissolved in 280 mL of dichloromethane. The reaction mixture was added with 16.2 g (84.89 mmol) of N-(3-dimethylaminopropyl)-N-(4-(2-nitropropoxy)-1 ... ` -Ethylcarbodiimide hydrochloride was treated continuously and stirred at room temperature (RT) for 16 hours. The reaction mixture was diluted with water and extracted with dichloromethane. The combined organic layers were washed with brine, dried over sodium sulfate, filtered and evaporated under vacuum to give a yellow solid. The crude product was purified by column chromatography using silica gel and heptane / ethyl acetate (8:2) to give a colorless solid.

[0714] 1.13. Synthesis of 4-hydroxy-3-methylphenyl 4-[(6-{[tri(propyl-2-yl)silyl]oxy}hexyl)oxy]benzoate 18

[0715]

[0716] 39.0 g (65.8 mmol) of compound 17 were dissolved in 390 mL of tetrahydrofuran and 15.0 g (140.9 mmol) of Pd-C (5% basic) were added and the reaction mixture was treated with a hydrogen atmosphere at normal pressure and room temperature for 45 minutes. The catalyst was filtered off and the reaction mixture was evaporated under vacuum. The crude product (crystallized oil) was purified by column chromatography using 1-chlorobutane and ethyl acetate (8:2). The obtained product was crystallized from acetonitrile.

[0717] 1 H NMR (500MHz, CDCl3) δ = 1.06 (m c ,21H,Si-(C3H7)3),1.40-1.53(m,2H,CH2),1.56(quint,J=7.73Hz,2H,CH2),1.83(7.82Hz,2H,CH2),2.25(s,3H,CH3),3.70(t, J=6.46Hz,2H,CH2),4.04(t,J=6.53Hz,2H,CH2),4.78(s,1H,OH),6.76(d,J=8.58Hz,1H),6.88(dd,J=2.76,8.56Hz,1H),6.95(m c ,3H),8.12(d,J=8.91Hz).

[0718] 1.14. Synthesis 19

[0719]

[0720] A solution of 5.4 g (11.3 mmol) of 5 and 5.5 g (10.3 mmol) of 18 in 60 ml of dichloromethane was treated with 60 mg of DMAP and 2.3 g (12 mmol) of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and stirred overnight at room temperature. The mixture was filtered through silica gel (dichloromethane). The solvent of the product-containing fractions was evaporated to give 19.

[0721] 1.15. Synthesis 20

[0722]

[0723] A solution of 4.0 g (4.2 mmol) of 19 in 80 ml of THF was treated with 10 ml of 2N hydrochloric acid at a temperature below 5°C. The reaction mixture was stirred at room temperature overnight and diluted with MTB ether. The organic layer was dried over sodium sulfate and the solvent was evaporated. The fractions containing the product were combined and the solvent was evaporated. The residue was suspended in 20 ml of acetonitrile and stirred at room temperature. The mixture was cooled to 6°C. The precipitate was isolated to give 20.

[0724] 1.16. Synthesis 21

[0725]

[0726] A mixture of 2.6 g (4 mmol) 20 and 50 ml of dichloromethane was treated with 1.0 ml (12 mmol) methacrylic acid and 100 mg DMAP. At 5°C, 2.8 ml (16 mmol) N-(3-dimethylaminopropyl)-N'-ethyl dissolved in 25 ml of DCM was added. After stirring at this temperature for 1 hour, stirring was continued at room temperature overnight. The reaction mixture was purified by silica gel chromatography (dichloromethane / acetonitrile 1:9). Further purification by treating the DCM solution with activated carbon and subsequent evaporation of the solvent gave 21.

[0727] 1.17. Synthesis 22

[0728]

[0729] A solution of 3.5 g (11.7 mmol) of 8 and 6 g (11.9 mmol) of 18 in 70 ml of dichloromethane was treated with 73 mg of DMAP and 2.8 g (14.6 mmol) of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and stirred overnight at room temperature. The mixture was purified by silica gel chromatography (dichloromethane). The solvent of the product-containing fractions was evaporated to give 22.

[0730] 1.18. Synthesis 23

[0731]

[0732] A solution of 5.1 g (6.5 mmol) of 22 in 80 ml of THF was treated with 8.5 ml of 2N hydrochloric acid at a temperature below 25°C. The reaction mixture was stirred at room temperature for 4 hours and diluted with MTB ether. The organic layer was dried over sodium sulfate and the solvent was evaporated. The fractions containing the product were combined and the solvent was evaporated. The residue mixture was purified by silica gel chromatography (dichloromethane / ethyl acetate, gradient 0 to 30%) to give 23.

[0733] 1.19. Synthesis 24 (RM-1)

[0734]

[0735] A mixture of 0.8 g (90%, 1.3 mmol) of 23 and 5 ml of dichloromethane was treated with 0.6 ml (7 mmol) of methacrylic acid and 100 mg of DMAP. 2.8 ml (16 mmol) of 1-(3-dimethylaminopropyl)-N'-ethylcarbodiimide dissolved in 5 ml of DCM was added at 5°C. After stirring at this temperature for 1 hour, stirring was continued at room temperature overnight. The reaction mixture was purified by silica gel chromatography (dichloromethane / ethyl acetate, gradient 0 to 0.3%) to give 24.

[0736] 1.20. Synthesis 25

[0737]

[0738] A solution of 3.4 g (98%, 7.1 mmol) of 5 and 2.6 g (6.5 mmol) of 13 in 40 ml of dichloromethane was treated with 35 mg of DMAP and 1.5 g (7.8 mmol) of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and stirred overnight at room temperature. The mixture was filtered through silica gel (dichloromethane). The solvent of the product-containing fractions was evaporated and 25 was obtained as a yellow oil.

[0739] 1.21. Synthesis 26

[0740]

[0741] A solution of 5.3 g (98%, 6.1 mmol) of 25 in 50 ml of THF was treated with 5 ml of triethylamine containing hydrogen fluoride at a temperature below 5° C. The reaction mixture was stirred at room temperature overnight and purified by silica gel chromatography (DCM / THF gradient 10% to 20%) to give 26.

[0742] 1.22. Synthesis of 27 (RM-2)

[0743]

[0744] A mixture of 3.3 g (95%, 5.8 mmol) of 26 and 20 ml of dichloromethane was treated with 2.7 ml (32 mmol) of methacrylic acid and 70 mg of DMAP. At 5°C, 2.8 ml (16 mmol) of N-(3-dimethylaminopropyl)-N'-ethyl dissolved in 10 ml of DCM was added. After stirring at this temperature for 1 hour, stirring was continued at room temperature overnight. The reaction mixture was purified by silica gel chromatography (DCM). Further purification was performed by treating the solution in acetone with activated carbon. Crystallization from acetone gave 27 (RM-2).

[0745] According to or analogously to the above procedure or to the procedure described in WO 2017 / 102068 and JP 2006-6232809, the following compounds were obtained:

[0746]

[0747] Nematic host mixture

[0748] The following nematic LC host mixtures were prepared as indicated in the table below:

[0749]

[0750]

[0751]

[0752] Display box manufacturing

[0753] Unless explicitly stated otherwise, display cells were made using 6.4 μm spacer beads and XN-1500T sealant with 0.7 mm thick Corning AF glass.

[0754] For the electro-optical measurements, 3 μm thick PI-free IPS cells were made from commercially available substrates from SD-tech and constructed using ITO electrodes with 5 μm electrode spacing and 3 μm electrode width.

[0755] The cell was assembled by hand and then heated using a 35 mW / cm 2 The samples were cured using an Omnicure 2000 mercury lamp, with the irradiation power measured by an Opsytec UV pad-e spectroradiometer.

[0756] Mixture Examples

[0757] The nematic LC mixtures M-1 to M-24 of the present invention are prepared from the nematic host mixtures N-1 to N-9 listed above and the photoalignment additive of formula I according to the compositions given in the table below.

[0758]

[0759]

[0760] Box filling and curing

[0761] Unless explicitly stated otherwise, the selected LC mixtures were capillary filled at room temperature using capillary action, annealed at 100 °C for 1 h and then irradiated with linearly polarized UV light (35 mW / cm 2) were irradiated at the same temperature for a given time. The box was then cooled to room temperature. Next, the alignment quality between the crossed polarizers on the light box was investigated.

[0762]

[0763] Alignment quality: (++) excellent, (+) good, (o) acceptable, (-) poor

[0764] With all mixtures at least a good uniform planar alignment was achieved.

[0765] VHR measurement

[0766] Unless explicitly stated otherwise, the selected LC mixtures were capillary filled at room temperature using capillary action, annealed at 100°C for 1 h and then irradiated at the same temperature with linearly polarized UV light (35 mW / cm2) from an Omnicure S2000 mercury lamp with a built-in 320-500 nm filter with an additional 360 nm long pass filter (cutting off shorter wavelengths of 320-360 nm).

[0767] The cell was then cooled to room temperature and then illuminated with linearly polarized UV light (35 mW / cm 2 ) for 10 minutes with UV light from an Omnicure S2000 mercury lamp with a built-in 320 to 500 nm filter using an additional 360 nm long pass filter (cutting off the shorter wavelengths of 320 to 360 nm).

[0768] Next, the VHR was studied using a Toyo LCM-1LC material properties measurement system. Unless otherwise stated, the measurement of VHR was performed as described in T. Jacob, U. Finkenzeller, "Merck Liquid Crystals-Physical Properties of Liquid Crystals", 1997.

[0769] VHR measured at 60°C, 1Hz and 1V after curing using a 360nm cutoff filter

[0770]

[0771] VHR measured at 60°C, 3Hz and 1V after curing using a 360nm cutoff filter

[0772]

[0773] VHR measured at 60°C, 60Hz and 1V after curing using a 360nm cutoff filter

[0774]

[0775]

[0776] As can be seen from the table given above, the VHR of the test cells according to the invention show excellent values. In particular, the combination of RM-2 and RM-4 with the LC host mixture N-2 having negative dielectric anisotropy shows unexpectedly favorable VHR values.

Claims

1. A compound of formula I, in A 11 Representation group A is independent of each other and represents a) the group consisting of 1,4-phenylene and 1,3-phenylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, L, in each occurrence, identically or differently, represents -OH, -F, -Cl, -Br, -I, -CN, -NO2, -SF5, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R z )2, -C(=O)R z 、-N(R z )2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms or linear, branched or cyclic alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which one or more H atoms may be replaced by F or Cl, or represents X 21 -Sp 21 -R 21 , Y 11 and Y 12 each independently of one another represents H, F, phenyl or an optionally fluorinated alkyl group having 1 to 12 C atoms, Z represents, independently of each other, a single bond, -COO-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -OCF2-, -CF2O-, -(CH2) at each occurrence n -, -CF2CF2-, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, -CO-S-, -S-CO-, -CS-S-, -S-CS-, -S-CSS- or -C≡C-, n represents an integer between 2 and 8, o and p each and independently represent 0, 1 or 2, X 11 and X 21 represents, independently of one another at each occurrence, a single bond, -CO-O-, -O-CO-, -O-COO-, -O-, -CH=CH-, -C≡C-, -CF2-O-, -O-CF2-, -CF2-CF2-, -CH2-O-, -O-CH2-, -CO-S-, -S-CO-, -CS-S-, -S-CS-, -S-CSS- or -S-, Sp 11 represents a spacer group comprising 1 to 20 C atoms, wherein one or more non-adjacent and non-terminal CH2 groups may also be replaced by -O-, -S-, -NH-, -N(CH3)-, -CO-, -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-, -CF2-, -CF2O-, -OCF2-, -CH(alkyl)-, -CH(alkenyl)-, -CH(alkoxy)-, -CH(oxaalkyl)-, -CH=CH- or -C≡C-, but in such a way that no two O atoms are adjacent to each other and no two groups selected from -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O- and -CH=CH- are adjacent to each other, Sp 21 represents a single bond, R 11 represents P, R 21 represents P or halogen, CN, optionally fluorinated alkyl or alkenyl having up to 15 C atoms, wherein one or more non-adjacent CH2 groups may be replaced by -O-, -S-, -CO-, -C(O)O-, -OC(O)-, OC(O)-O-, P at each occurrence is each and independently of one another a polymerizable group selected from acrylate, methacrylate, fluoroacrylate, and vinyloxy, chloroacrylate, oxetane and epoxy groups.

2. The compound according to claim 1, characterized in that The linear or branched or cyclic alkyl group, alkoxy group, alkylcarbonyl group, alkoxycarbonyl group, alkylcarbonyloxy group or alkoxycarbonyloxy group has 1 to 12 carbon atoms.

3. The compound according to claim 1, characterized in that The linear or branched or cyclic alkyl group, alkoxy group, alkylcarbonyl group, alkoxycarbonyl group, alkylcarbonyloxy group or alkoxycarbonyloxy group has 1 to 6 carbon atoms.

4. The compound according to claim 1, characterized in that The compound is selected from the compounds of formula I-1 to I-9 in R 11 , R 21 , A 11 , X 11 , X 12 , Y 11 , Y 12 、Sp 11 and Sp 12 has one of the meanings given in claim 1 above, A 12 To A 23 has one of the meanings given to A according to claim 1, and Z 11 To Z 22 has one of the meanings given for Z in claim 1 above.

5. The compound according to any one of claims 1 to 4, characterized in that The compound is selected from the following sub-formulas: in R 11 , R 21 , X 11 , X 21 、Sp 11 and Sp 21 has one of the meanings given in claim 1 above, Z 11 and Z 21 has one of the meanings given above for Z in claim 1 and Group Each and independently Or besides Wherein L is F, Cl, CH3, OCH3 and COCH3 or an alkylene group having 1 to 6 C atoms or X 21 -Sp 21 -R 21 .

6. The compound according to any one of claims 1 to 4, characterized in that It is selected from the compounds of the following sub-formulae: R 11 , R 21 , X 21 and Sp 21 has one of the meanings given in claim 1 above, Z 21 has one of the meanings given above under claim 1 for Z, r, s, t and q each and independently of one another represent an integer from 1 to 8, Y each and independently of one another represent methyl or H, and Group Each and independently is or express as well as wherein L is F, Cl, CH3, OCH3 and COCH3 or an alkylene group having 1 to 6 C atoms, or X 21 -Sp 21 -R 21 .

7. The compound according to any one of claims 1 to 4, characterized in that It is selected from the compounds of the following sub-formulae: Among them, Sp 21 has one of the meanings given above in formula I and L represents F, Cl, OCH3 and COCH3 or an alkylene group having 1 to 6 C atoms and s represents an integer from 1 to 8.

8. The compound according to any one of claims 1 to 4, characterized in that It is selected from the compounds of the following sub-formulae: Among them, Sp 21 has one of the meanings given above in formula I and L represents F, Cl, OCH3 and COCH3 or an alkylene group having 1 to 6 C atoms and s represents an integer from 1 to 8.

9. The compound according to any one of claims 1 to 4, characterized in that It is selected from the compounds of the following sub-formulae: wherein L represents F, Cl, OCH 3 and COCH 3 or an alkylene group having 1 to 6 C atoms and s and t each and independently of one another represent an integer from 1 to 8.

10. The compound according to any one of claims 1 to 4, characterized in that It is selected from the compounds of the following sub-formulae: wherein L represents F, Cl, OCH3 and COCH3 or an alkylene group having 1 to 6 C atoms and t represents an integer of 1 to 8.

11. Use of a compound of the formula I according to any one of claims 1 to 10 in a liquid crystal mixture.

12. A liquid crystal mixture, characterized in that They comprise a component A) which comprises one or more compounds of the formula I according to any one of claims 1 to 10 and a liquid-crystalline component B) which comprises one or more mesogenic or liquid-crystalline compounds.

13. A liquid crystal mixture according to claim 12, characterised in that The total concentration of the compounds of formula I in the mixture is in the range of 0.01% to 10% by weight.

14. A liquid crystal mixture according to claim 12 or 13, characterised in that It further comprises a polymerizable component C) which comprises one or more polymerizable mesogens or polymerizable isotropic compounds.

15. Liquid crystal mixture according to claim 14, characterized in that The concentration of the polymerizable mesogen or polymerizable isotropic compound is in the range of 0.01 wt % to 10 wt %.

16. A liquid crystal mixture according to claim 14, characterised in that It contains one or more compounds of formula P P a -(Sp a ) s1 -A 2 -(Z 1 -A 1 ) n2 -(Sp b ) s2 -P b P in P a , P b each independently of one another represents a polymerizable group, Sp a 、Sp b represents a spacer group identically or differently on each occurrence, s1 and s2 are each independently 0 or 1, A 1 , A 2 Each independently represents a group selected from the following groups: a) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene and 4,4'-dicyclohexylene, in which one or more non-adjacent CH2 groups may be replaced by -O- and / or -S-, and in which one or more H atoms may be replaced by F, b) the group consisting of 1,4-phenylene and 1,3-phenylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, c) the group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, d) the group consisting of saturated, partially unsaturated or fully unsaturated and optionally substituted polycyclic radicals having 5 to 20 ring C atoms, one or more of which may additionally be replaced by heteroatoms, selected from: Furthermore, one or more H atoms in these groups may be replaced by L, and / or one or more double bonds may be replaced by single bonds, and / or one or more CH groups may be replaced by N, n2 is 0, 1, 2, or 3, Z 1 In each case, independently of one another, it represents -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n -, wherein n is 2, 3 or 4, -O-, -CO-, -C(R 0 R 00 )-, -CH2CF2-, -CF2CF2- or a single bond, L, identically or differently on each occurrence, represents F, Cl, CN, SCN, SF5 or linear or branched and in each case optionally fluorinated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to 12 C atoms, R 0 , R 00 each independently of one another represents H, F or a straight-chain or branched alkyl radical having 1 to 12 C atoms, wherein moreover one or more H atoms may be replaced by F, M represents -O-, -S-, -CH2-, -CHY 1 -or-CY 1 Y 2 -,and Y 1 and Y 2 Each independently has the above for R 0 One of the indicated meanings may represent Cl or CN.

17. A liquid crystal mixture according to claim 12 or 13, characterised in that LC host mixtures have negative dielectric anisotropy.

18. Liquid crystal mixture according to claim 17, characterized in that The LC host mixture comprises one or more compounds selected from the following formulae: in a is 1 or 2, b is 0 or 1, express R 1 and R 2 each independently of one another represents an alkyl radical having 1 to 12 C atoms, furthermore one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -O-CO- or -CO-O- in such a way that the O atoms are not directly connected to one another, Z x Indicates -CH=CH-, -CH2O-, -OCH2-, -CF2O-, -OCF2-, -O-, -CH2-, -CH2CH2- or a single bond, L 1-4 Each independently represents F, Cl, OCF3, CF3, CH3, CH2F, CHF2.

19. A liquid crystal mixture according to claim 12 or 13, characterised in that The LC host mixture has positive dielectric anisotropy.

20. A liquid crystal mixture according to claim 19, characterised in that The LC host mixture comprises one or more compounds selected from the group consisting of compounds of formula II and III: in R 20 each identically or differently represents a halogenated or unsubstituted alkyl or alkoxy group having 1 to 15 C atoms, wherein one or more CH2 groups in these groups may each independently of one another be connected via -C≡C-, -CF2O-, -CH=CH-, -O-, -CO-O- or -O-CO-, X 20 each identically or differently represents F, Cl, CN, SF5, SCN, NCS, a halogenated alkyl, a halogenated alkenyl, a halogenated alkoxy or a halogenated alkenyloxy, each having up to 6 C atoms, and Y 20-24 each identically or differently represents H or F, W represents H or methyl, n and d Each of the same or different 21. A liquid crystal mixture according to claim 19, characterized in that It comprises one or more compounds selected from the group consisting of compounds of formula XI and XII: Where R 20 , X 20 , W and Y 20-23 has the meaning indicated in formula III in claim 18, and and Each independently expresses and express 22. A liquid crystal mixture according to claim 12 or 13, characterised in that The LC host mixture comprises one or more compounds of the following formula: The various groups have the following meanings: express express R 3 and R 4 each independently of one another represents an alkyl radical having 1 to 12 C atoms, furthermore one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -O-CO- or -CO-O- in such a way that the O atoms are not directly connected to one another, Z y Represents -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO- O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond.

23. A liquid crystal mixture according to claim 12 or 13, characterised in that The LC host mixture comprises one or more compounds of the following formulae: Among them, propyl, butyl and pentyl are straight chain groups.

24. A liquid crystal mixture according to claim 12 or 13, characterised in that The LC host mixture comprises one or more compounds selected from the following formulae: wherein alkyl and alkyl* each independently represent a straight-chain alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl* each independently represent a straight-chain alkenyl group having 2 to 6 C atoms.

25. A liquid crystal mixture according to claim 12 or 13, characterised in that The LC host mixture comprises one or more compounds selected from the following formulae: Therein alkyl* represents an alkyl group having 1 to 6 C atoms.

26. Use of a liquid crystal mixture according to any one of claims 12 to 25 for the production of liquid crystal displays.

27. A method for manufacturing a liquid crystal display, comprising at least the following steps: ● providing a first substrate, which includes a pixel electrode and a common electrode, wherein the electrodes are used to generate an electric field substantially parallel to the surface of the first substrate in the pixel area; ●Providing a second substrate, the second substrate being arranged opposite to the first substrate; ● insertion of a liquid crystal mixture according to any one of claims 12 to 25; ● irradiating the liquid crystal mixture with linearly polarized light to induce photo-alignment of the liquid crystal; The polymerizable compound of the liquid crystal mixture is cured by irradiation with ultraviolet light or visible light having a wavelength of 450 nm or less.

28. The method according to claim 27, characterized in that The linearly polarized light is ultraviolet light or visible light having a wavelength of 450 nm or less.

29. A display obtainable by a method according to claim 27 or 28.

30. A display according to claim 29, wherein the LC host mixture is aligned in the plane in the absence of an applied electric field.

31. A display according to claim 29 or 30, wherein the display is an IPS or FFS display.

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