CN121311566A - Liquid crystal media - Google Patents

Abstract

The present invention relates to dichroic dye compounds of formula I as defined in claim 1, based on a donor-acceptor structure, wherein the donor moiety comprises a polycyclic heteroaromatic group consisting of at least four fused rings, to mesogenic media comprising one or more compounds of formula I, and to the use of these compounds, mesogenic media and liquid crystal materials in optical, electronic and electro-optical applications, in particular in devices for regulating the passage of energy through an external space into an internal space, such as switchable windows for solar control in smart buildings and vehicles, with energy saving and improved comfort.

Description

Liquid-crystalline medium

Technical Field

The present invention relates to dichroic dye compounds of formula I as defined below, based on donor-acceptor structures, wherein the donor moiety comprises a polycyclic heteroaromatic group consisting of at least four fused rings, to mesogenic media comprising one or more compounds of formula I, and to the use of these compounds and mesogenic media in optical, electronic and electro-optical applications, in particular in devices for regulating the passage of energy through an external space into an internal space, such as switchable windows for solar control in smart buildings and vehicles, with energy saving and improved comfort.

Background

The reviews "Properties, requirements and possibilities of smart windows for dynamic daylight and solar energy control in buildings: A state-of-the-art review",Solar Energy Materials & Solar Cells 94 (2010) of r, baetens et al, pages 87 to 105, describe tintable smart windows. Smart windows may utilize a variety of techniques for adjusting light transmittance, such as electrochromic-based devices, liquid crystal devices, and electrophoretic or suspended particle devices. Liquid crystal-based devices employ a change in the orientation of liquid crystal molecules between two conductive electrodes by application of an electric field, resulting in a change in their transmittance.

Liquid crystal materials are used in particular as dielectrics in display devices, wherein the optical properties of such materials can be influenced by an applied voltage. Electro-optic devices based on liquid crystals are well known in the art and may be based on a variety of effects. Devices of this type are, for example, cells with dynamic scattering, DAP (aligned phase change) cells, TN cells with twisted nematic structures, STN ("supertwisted nematic") cells, SBE ("superbirefringence effect") cells, OMI ("optical mode interference") cells and guest-host cells.

Devices based on the guest-host effect were first described by Heilmeier and Zanoni (g.h. Heilmeier et al, appl. Phys. Lett., 1968, 13, 91 f.), and have been widely used hereafter, primarily in Liquid Crystal (LC) display elements. In a guest-host system, the LC medium contains one or more dichroic dyes in addition to the liquid crystal. Due to the directional dependence of dye molecule absorption, the transmittance of dye doped liquid crystals can be adjusted when the dye changes its alignment along with the liquid crystals.

In addition to its use in LC displays, this type of device also serves as a switching element for regulating the passage of light or energy, as described for example in WO 2009/141295 and WO 2010/118422.

Many different technical solutions have been proposed for devices for regulating the passage of energy through an external space into an internal space.

In some devices, the light transmittance may be reversibly changed, wherein the intensity of incident light may be cut, attenuated, or colored. Such devices may thus operate and switch between a bright state and a dark state (i.e., a relatively higher light transmittance state and a relatively lower light transmittance state).

In one possible mode for the device, a liquid crystal medium in combination with one or more dichroic dyes as described above may be used in the switching layer. By applying a voltage, a change in the orientation alignment of the dichroic dye molecules can be achieved in such a switching layer. Due to the direction dependent absorption, a change in the transmittance of the switching layer can thus be obtained. Corresponding devices are described for example in WO 2009/141295.

Alternatively, such a change in transmission behaviour can also be achieved by a temperature-induced transition from the isotropic state of the liquid crystal medium to the liquid crystal state in the absence of a voltage, as described for example in US 2010/0259698.

WO 2009/141295 and WO 2010/118422 describe liquid crystal media for guest-host type optical devices comprising a cyanobiphenyl derivative and one or more dichroic dyes. The (rylene) dyes have been described for use in the devices mentioned above, for example in WO 2009/141295, WO 2013/004677 and WO 2014/090373. The use of benzothiadiazoles in the devices mentioned above is described in WO 2014/187529 and WO 2020/104563, and the use of thiadiazoloquinoxalines in the devices mentioned above is described in WO 2016/177449 and WO 2020/104563.

There remains a need in the art for dichroic dye compounds and media comprising these compounds that provide benefits in terms of device performance and reliability.

Disclosure of Invention

It is therefore an object of the present invention to provide improved dye compounds which are particularly suitable for guest-host applications and which may advantageously contribute to the effective and efficient performance of switchable devices.

Another object is to provide an improved mesogenic medium which comprises these compounds and which shows a broad and stable LC phase range and a particularly advantageous low temperature stability and which furthermore can give rise to a suitably high degree of order.

Another object is to provide a stable and reliable switching medium for electro-optical applications, which allows particularly advantageous properties in devices for regulating the passage of energy through an external space into an internal space, in particular in smart switchable windows, for example in terms of stability and contrast or aesthetic impression with respect to direct and prolonged irradiation of sunlight. Other objects of the present invention will be apparent to those skilled in the art from the following detailed description.

The above object is achieved by the subject matter defined in the independent claims, while preferred embodiments are set forth in the respective dependent claims and are further described below.

The invention provides, inter alia, the following items, including main aspects, preferred embodiments and specific features, each alone and in combination helping to solve the above objects and ultimately providing further advantages.

A first aspect of the invention provides a compound of formula I:

Wherein the method comprises the steps of

R ¹ and R ² are identical or different and represent H, F, CN, N (R ^z)₂, straight-chain alkyl having 1 to 20C atoms or branched or cyclic alkyl having 3 to 20C atoms, where, in addition, one or more non-adjacent CH ₂ groups can each, independently of one another, be replaced by-C (R ^z)=C(R^z) -, -C≡C-,、、、、-N (R ^z) -, -O-, -S-, -CO-O-, -O-CO-, or-O-CO-O-is replaced in such a manner that O and/or S atoms are not directly connected to each other, and wherein, in addition, one or more H atoms can be replaced by F, cl, br, I or CN,

R ^z represents, identically or differently for each occurrence, H, halogen, straight-chain alkyl having 1 to 12C atoms or branched or cyclic alkyl having 3 to 12C atoms, where, in addition, one or more non-adjacent CH ₂ groups may be replaced by-O-, -S-, -CO-O-, O-CO-or-O-CO-O-is replaced in such a way that the O and/or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may be replaced by F or Cl,

Q ¹ and Q ², which are identical or different, represent a single bond 、-O-、-S-、-CF₂O-、-OCF₂-、-CF₂-、-CF₂CF₂-、-CO- -CR^x1=CR^x2-、-C≡C-、-NR^x1-、-N=N- or an alicyclic or heterocyclic group, preferably having 4 to 25 ring atoms, which may also contain condensed rings, and which is unsubstituted or monosubstituted or polysubstituted by L,

Z ¹ and Z ², which are identical or different, represent a single bond 、-O-、-S-、-C(O)-、-CR^y1R^y2-、-CF₂O-、-OCF₂-、-C(O)-O-、-O-C(O)-、-O-C(O)-O-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂S-、-SCF₂-、-(CH₂)_n1-、-CF₂CH₂-、-CH₂CF₂-、-(CF₂)_n1-、-CR^x1=CR^x2-、-C≡C-、-CR^x1=CR^x2-CO-、-CO-CR^x1=CR^x2-、-CR^x1=CR^x2-COO-、-OCO-CR^x1=CR^x2- or-N=N-,

R ^x1、R^x2 independently of one another represents H, F, cl, CN or alkyl having 1 to 12C atoms,

R ^y1 represents H or an alkyl group having 1 to 12C atoms,

R ^y2 represents an alkyl group having 1 to 12C atoms,

N1 represents 1, 2, 3 or 4,

A ¹ and A ², which are identical or different, represent aromatic, heteroaromatic, cycloaliphatic or heterocyclic radicals, preferably having from 4 to 25 ring atoms, which may also comprise condensed rings, and which are unsubstituted or monosubstituted or polysubstituted by L,

L represents F, cl, -CN or a linear alkyl having 1 to 25C atoms or a branched or cyclic alkyl having 3 to 25C atoms, wherein one or more non-adjacent CH ₂ -groups are optionally replaced by-O-, -S-, -CO-O-, O-CO-or-O-CO-O-is replaced in such a way that O atoms and/or S atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by F or Cl,

D represents a donor, preferably an electron-rich conjugated moiety, selected from heteroaromatic groups comprising at least 4 fused rings, preferably at least 4 linear fused rings, wherein each ring may be unsubstituted or mono-or polysubstituted by L,

A represents an acceptor group, preferably an electron-deficient moiety,

N represents 0, 1, 2 or 3, preferably 0, 1 or 2, and

O represents either 0 or 1 and,

Wherein the number of rings (including fused rings) in the compound is at least 5.

The term "ring" herein refers to a cyclic group having a closed ring structure, i.e., a closed ring of atoms. The rings herein also include cyclic, condensed or fused rings, particularly edge-to-edge fused rings, wherein a ring is fused if it shares two or more atoms. In this regard, compounds (particularly multicyclic compounds) are believed to contain a number of rings equal to the number of breaks required to convert them to open-chain compounds.

The combination of donors D herein adjacent to acceptor A preferably forms a pi conjugated system. The donor group D comprises or preferably consists of an unsubstituted or substituted heteroaromatic group, in particular a polycyclic heteroaromatic group comprising fused rings, preferably an unsubstituted or substituted heteroacene, more preferably an unsubstituted or substituted S, N-heteroacene with extended pi-conjugation.

The acceptor group A is preferably an electron withdrawing group, preferably an electron-deficient moiety, which is pi-electron deficient.

The groups Z ¹ and Z ² directly adjacent to groups D and A, if present, are preferably single bonds or pi conjugated groups.

It has surprisingly been found that the compounds of formula I as described herein exhibit excellent combination properties and characteristics, e.g. in terms of extinction coefficient, stability and solubility, which may lead to beneficial properties in optical, electro-optical and electronic applications, and in particular in guest-host applications, such as in dimmable smart windows. In particular, the compounds according to the invention have excellent solubility and stability in liquid crystalline media.

In particular, it has surprisingly been found that the compounds of formula I have an advantageous solubility in liquid-crystalline media, while at the same time yielding suitable light and temperature stability. In addition, the compounds as mixtures may exhibit advantageous compatibility and stability, with the possibility of high color purity and thus providing media with a neutral or grey appearance as desired. While the compound may produce only weak or even no discernible fluorescence.

It has now been found that compounds of the formula I can advantageously exhibit large extinction coefficients in the VIS and/or NIR region of light, while furthermore having a suitably high dichroism ratio. It is currently recognized that such combination characteristics may advantageously contribute to effective and efficient device performance. A high extinction coefficient, particularly in conjunction with a high dichroism ratio, may be beneficial in that lower dye concentrations may be used and/or a single switching layer may be sufficient and/or a smaller switching layer thickness or cell gap may be sufficient to obtain the desired contrast and effective dark state. Smaller dye concentrations may also have benefits in terms of solubility and viscosity considerations.

The compounds of the formula I are therefore particularly suitable for guest-host applications, in which the dye-doped mesogenic media can exhibit a suitably broad and stable LC phase range and in particular advantageous low-temperature stability. The mesogenic media according to the invention may thus yield benefits in terms of device performance and reliability, in particular in smart switchable windows.

It has also been found that the compounds not only show advantageous solubility in LC media themselves, but that they can be thoroughly mixed in such media together with other dichroic dye compounds. This advantageously helps to improve the ability to provide custom dye doped liquid crystal media, especially in terms of creating a specific color or even covering the entire VIS range to achieve a black appearance. In this regard, the compounds of formula I may be selected and adjusted such that the desired color is produced while exhibiting only very little or even no fluorescence at all.

Thus, in a further aspect, there is provided a composition, in particular a mixture, comprising two or more compounds, preferably three or more compounds, more preferably four or more compounds according to the invention.

The compounds according to the invention can be advantageously used in liquid-crystalline media, as described herein.

Thus, another aspect relates to a liquid-crystalline medium further comprising one or more compounds according to the invention in addition to at least one mesogenic compound. Preferably, the liquid-crystalline medium contains two or more compounds of the formula I or corresponding preferred subformulae, more preferably three or more compounds of the formula I or corresponding preferred subformulae.

It has been found that the liquid-crystalline medium according to the invention can produce a stable, reliable and highly efficient switching medium for electro-optical applications, which allows particularly advantageous properties in devices for regulating the passage of energy through an external space into an internal space, in particular in smart switchable windows. In this regard, the high extinction coefficient and favorable dichroism ratio of the compounds of formula I in the medium may contribute to beneficial properties in guest-host applications such as in dimmable smart windows.

Thus, in a further aspect according to the invention, a device for regulating the passage of energy through an external space into an internal space is provided, wherein the device contains a switching layer comprising a liquid crystal medium according to the invention as described herein. In particular, the device may be comprised in a window.

In a further aspect of the invention, the compounds and mesogenic media according to the invention are used in electro-optical displays, in devices for regulating the passage of energy through an external space into an internal space, electronic semiconductors, organic field effect transistors, printed circuits, radio frequency identification elements, diodes, organic light emitting diodes, illumination elements, photovoltaic devices (in particular as sensitizers or semiconductors therein), optical sensors, effect pigments, decorative elements or as dyes for coloring polymers, for example in the automotive field.

In a further aspect, a window is provided comprising means for regulating the passage of energy through an external space into an internal space, wherein the means comprises a switching layer comprising a liquid crystal medium according to the invention.

The liquid crystal window according to the invention can be used in sustainable glass applications in buildings and vehicles, in particular by generating energy savings with respect to lighting, cooling and/or heating and by positively influencing the life cycle (e.g. in terms of maintenance) while additionally providing improved thermal and visual comfort.

In another aspect according to the present invention, there is provided a process for preparing a compound of formula I. In particular, this method results in a simple process which is easy to prepare to obtain the compounds according to the invention.

Without limiting the invention, its aspects, embodiments and specific features are set forth below by way of detailed description of the invention, and specific embodiments are described in greater detail.

In the present invention, means for adjusting the passage of energy through the outer space into the inner space preferably refers to means for adjusting the passage of energy, in particular light and in particular sunlight, through an area arranged within a structure of relatively low energy transmission. The lower energy transmittance structure may be a wall. The energy can thus pass, for example, through open areas or especially glass areas in the wall. The device is therefore preferably arranged as an integral part of a window, such as an insulating glass unit.

The passage of the regulated energy is from an external space (preferably an environment exposed to direct or indirect solar light irradiation) into an internal space (e.g. a building or a vehicle, or another unit substantially isolated from the environment).

For the purposes of the present invention, the term "energy" refers to the energy which is produced in particular by electromagnetic radiation in the UV-A, VIS and NIR regions. In particular, it refers to the energy generated by radiation that is not absorbed or is absorbed only to a negligible extent by the materials typically used in windows (e.g. glass). Herein, the UV-A region refers to wavelengths in the range of 320 to 380 nm, the VIS region refers to wavelengths in the range of 380 nm to 780 nm and the NIR region refers to wavelengths in the range of 780 nm to 2000 nm. Accordingly, the term "light" generally refers to electromagnetic radiation having a wavelength between 320 and 2000 nm, and in particular 380 nm to 780 nm.

In this context, a dichroic dye refers to a light absorbing compound, wherein the absorption properties depend on the orientation of the compound with respect to the polarization direction of the light. The dichroic dye compounds according to the present invention generally have an elongated shape, i.e. the compound is significantly longer in one spatial direction (i.e. along the longitudinal axis) than the other two spatial directions.

The term "organic group" means a carbon or hydrocarbon group.

The term "carbon-based" denotes a monovalent or polyvalent organic group containing at least one carbon atom, wherein this group does not contain other atoms, such as, for example, -c≡c-, or optionally contains one or more other atoms, such as, for example N, O, S, P, si, se, as, te or Ge, for example carbonyl, etc. The term "hydrocarbyl" denotes a carbon-based group that additionally contains one or more H atoms and optionally one or more heteroatoms, such as, for example, N, O, S, P, si, se, as, te or Ge.

"Halogen" means F, cl, br or I, preferably F or Cl.

The carbon or hydrocarbon group may be a saturated group or an unsaturated group. Unsaturated groups are, for example, aryl, alkenyl or alkynyl groups. The carbon or hydrocarbon groups having 3 or more atoms may be linear, branched, and/or cyclic and may also contain spiro linkages or fused rings.

The terms "alkyl", "aryl", "heteroaryl" and the like also include multivalent groups such as alkylene, arylene, heteroarylene and the like.

The term "aryl" means an aromatic carbon group or a group derived therefrom. The term "heteroaryl" means an "aryl" group, as defined above, containing one or more heteroatoms.

Preferred carbon groups and hydrocarbon 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 18C atoms, optionally substituted aryl or aryloxy groups having 6 to 40, preferably 6 to 25C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryl, arylalkoxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy groups having 6 to 40, preferably 6 to 25C atoms.

Other preferred carbon and hydrocarbon groups are C ₁-C₄₀ alkyl, C ₂-C₄₀ alkenyl, C ₂-C₄₀ alkynyl, C ₃-C₄₀ allyl, C ₄-C₄₀ Alkyldienyl, C ₄-C₄₀ polyalkenyl, C ₆-C₄₀ aryl, C ₆-C₄₀ alkylaryl, C ₆-C₄₀ arylalkyl, C ₆-C₄₀ alkylaryl, C ₆-C₄₀ arylalkoxy, C ₂-C₄₀ heteroaryl, C ₄-C₄₀ cycloalkyl, C ₄-C₄₀ cycloalkenyl, and the like. Particularly preferred are C ₁-C₂₂ alkyl, C ₂-C₂₂ alkenyl, C ₂-C₂₂ alkynyl, C ₃-C₂₂ allyl, C ₄-C₂₂ alkyldienyl, C ₆-C₁₂ aryl, C ₆-C₂₀ arylalkyl and C ₂-C₂₀ heteroaryl.

Other preferred carbon and hydrocarbon radicals are straight-chain, branched or cyclic alkyl radicals having from 1 to 40, preferably from 1 to 25, C atoms, which is unsubstituted or mono-or polysubstituted by F, cl, br, I or CN and in which one or more non-adjacent CH ₂ groups can each be, independently of one another, substituted by-C (R ^z)=C(R^z)-、-C≡C-、-N(R^z) -, by-O-, -S-, -CO-O-, -O-CO-O-is replaced in such a manner that O and/or S atoms are not directly linked to each other.

R ^z preferably represents H, halogen, a straight, branched or cyclic alkyl chain having 1 to 25C atoms, wherein, in addition, one or more non-adjacent C atoms may be replaced by-O-, -S-, -CO-O-, -O-CO-or-O-CO-O-substitution and wherein one or more H atoms may be replaced by fluorine, an optionally substituted aryl or aryloxy group having 6 to 40C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40C atoms.

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-trifluoroethyl, perfluorooctyl and perfluorohexyl.

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

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

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-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy and n-dodecoxy.

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

Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e., they can contain one ring, such as, for example, phenyl, or two or more rings, which can also be fused, such as, for example, naphthyl, or covalently bonded, such as, for example, biphenyl, or a combination containing a fused ring and a linking ring. Heteroaryl contains one or more heteroatoms, preferably selected from O, N, S and Se. Ring systems of this type may also contain individual non-conjugated units, as in this case, for example, in the basic structure of fluorene.

Particularly preferred are monocyclic, bicyclic or polycyclic aryl groups having 6 to 50C atoms and monocyclic, bicyclic or polycyclic heteroaryl groups having 2 to 50C atoms, which optionally contain fused rings and are optionally substituted. Preference is furthermore given to 5-, 6-or 7-membered aryl and heteroaryl groups, where, in addition, one or more CH groups can be replaced by N, S or O in such a way that O atoms and/or S atoms are not directly connected to one another.

Preferred aryl groups are derived, for example, from the parent structure benzene, biphenyl, terphenyl, [1,1':3',1 "] terphenyl, naphthalene, anthracene, binaphthyl, phenanthrene, pyrene, dihydropyrene, fu, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, and the like.

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-thiadiazole, 1,2, 5-thiadiazole, 1,3, 4-thiadiazole, 6-membered rings, 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, 1,3, 5-tetrazine, or fused groups, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthazole, phenanthroimidazole, pyridoimidazole, pyrazinoimidazole, quinoxalinoimidazole, benzoxazole, naphthazole, anthraceneoxazole, phenanthroazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5, 6-quinoline, benzo-6, 7-quinoline, benzo-7, 8-quinoline, benzisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno [2,3b ] thiophene, thieno [3,2b ] thiophene, dithiophene, dihydrothieno [3,4-b ] -1, 4-dioxazine, isobenzothiophene, dibenzothiophene, benzothiophene, benzothiadiazole, or a combination of such groups. Heteroaryl groups may also be substituted with alkyl, alkoxy, sulfanyl, fluoro, fluoroalkyl, or other aryl or heteroaryl groups.

The (non-aromatic) alicyclic and heterocyclic groups comprise saturated rings, i.e. those containing only single bonds, and also 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.

The (non-aromatic) alicyclic and heterocyclic groups may be monocyclic, i.e. contain only one ring, such as, for example, cyclohexane, or polycyclic, i.e. contain multiple rings, such as, for example, decalin or bicyclooctane. Saturated groups are particularly preferred. Preference is furthermore given to monocyclic, bicyclic or tricyclic groups having 3 to 25C atoms, which optionally contain fused rings and are optionally substituted. Preference is furthermore given to 5-, 6-, 7-or 8-membered carbocyclic radicals in which, in addition, one or more C atoms can be replaced by Si and/or one or more CH groups can be replaced by N and/or one or more non-adjacent CH ₂ groups can be replaced by-O-and/or-S-.

Preferred cycloaliphatic and heterocyclic groups are, for example, 5-membered groups such as cyclopentane, tetrahydrofuran, tetrahydrothiofuran, pyrrolidine, 6-membered groups such as cyclohexane, silacyclohexane (silinane), cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1, 3-dioxane, 1, 3-dithiane, piperidine, 7-membered groups such as cycloheptane, and fused groups such as tetrahydronaphthalene, 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-bridged indan-2, 5-diyl.

Aryl, heteroaryl, carbon and hydrocarbyl groups optionally have one or more substituents, which are preferably selected from the group comprising silyl, sulfo, sulfonyl, formyl, amino, imino, nitrile, mercapto, nitro, halogen, C _1-12 alkyl, C _6-12 aryl, C _1-12 alkoxy, hydroxy, or a combination of such groups.

Preferred substituents are, for example, dissolution promoting groups such as alkyl or alkoxy groups, electron withdrawing groups such as fluorine, nitro or nitrile groups, or substituents for increasing the glass transition temperature (T _g) in the polymer, in particular bulky groups such as, for example, tert-butyl or optionally substituted aryl groups.

Preferred substituents are F、Cl、Br、I、-CN、-NO₂、-NCO、-NCS、-OCN、-SCN、-C(=O)N(R^z)₂、-C(=O)Y¹、-C(=O)R^z、-N(R^z)₂, wherein R ^z has the meaning indicated above, and Y ¹ represents halogen, optionally substituted silyl or aryl having 6 to 40, preferably 6 to 20C atoms, and straight or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25C atoms, wherein one or more H atoms may optionally be replaced by F or Cl.

More preferred substituents are, for example F、Cl、CN、NO₂、CH₃、C₂H₅、OCH₃、OC₂H₅、COCH₃、COC₂H₅、COOCH₃、COOC₂H₅、CF₃、OCF₃、OCHF₂、OC₂F₅, furthermore, phenyl.

In this context, the substituents representing L are identical or different on each occurrence and are preferably F, cl, CN, SCN, SF ₅ or straight-chain or branched, in each case optionally fluorinated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12C atoms.

Preferably, L represents, identically or differently for each occurrence, F or a straight-chain or branched chain having 1 to 7C atoms, in each case optionally fluorinated alkyl or alkoxy.

"Substituted monosilane or aryl" preferably means substituted by halogen, -CN, R ^y1、-OR^y1、-CO-R^y1、-CO-O-R^y1、-O-CO-R^y1 or-O-CO-O-R ^y1, wherein R ^y1 has the meaning indicated above.

As described herein, the compounds of formula I have donor-acceptor combinations in their molecular structure that produce extremely high extinction coefficients, particularly in the visible region, while also exhibiting advantageous compatibility for use in guest-host applications, particularly with suitable solubility and stability in liquid crystal media.

According to the invention, the group D in formula I represents a donor group selected from unsubstituted or substituted heteroaromatic groups comprising at least 4 fused rings, preferably at least 4 linear fused rings, which provide an electron-rich conjugated moiety.

The donor group D is preferably a polycyclic group, in particular a tetracyclic, pentacyclic, hexacyclic or heptacyclic group, which is a heterocyclic aromatic group, i.e. an aromatic group in which at least one ring contains at least one non-carbon atom, preferably sulfur, nitrogen and/or oxygen. In particular, the polycyclic heteroaromatic group includes at least four fused rings, each of which may be unsubstituted or substituted, containing, for example, a thienopyrrole fused group.

In a preferred embodiment, the group D is selected from groups containing, preferably consisting of, linear fused rings, preferably unsubstituted or substituted heteroacenes. Particularly preferably, the group D contains a heterocyclic thiophene and a pyrrole ring, wherein preferably the group D contains and in particular consists of a fused heterocyclic thiophene and a pyrrole ring, preferably a substituted pyrrole ring, in particular a so-called S, N-heteroacene. Preferred are tetra-, penta-and hexa-ring systems, especially S, N-heterotetrabenzene, S, N-heterotentabenzene and S, N-heterotentabenzene, wherein such systems may be symmetrical or asymmetrical.

Heteroacenes herein are acene compounds which contain or preferably consist of heteroatom-substituted aromatic groups. In this regard, acenes herein are polycyclic aromatic hydrocarbons composed of fused benzene rings in a linear arrangement.

Preferably, the donor group D is a heteroacene having a linear fused ring, wherein each ring may be unsubstituted or mono-or polysubstituted by L, wherein L is defined as set forth above and below.

In one embodiment, Z ¹ and Z ² independently of one another represent a single bond, -ch=ch-, -cf=cf-, or-c≡c-. Particularly preferably, Z ¹ and Z ² represent a single bond.

The radicals R ¹ and R ² in the formula I preferably represent, independently of one another, alkyl, preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, or branched alkyl having 3 to 12C atoms, preferably methyl, ethyl, n-propyl, n-butyl or n-pentyl bonded to ethyl, n-propyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl, for example 2-ethylhexyl, 2-ethylheptyl, 2-ethyloctyl, 2-ethylnonyl, 2-ethyldecyl, 3-ethylhexyl, 3-ethylheptyl, 3-ethyloctyl, 3-ethylnonyl, 3-ethyldecyl, etc.

In another embodiment, the groups R ¹ and R ² independently of one another represent a linear or branched alkyl group or a dialkylamino group having 1 to 12C atoms per alkyl group.

In one embodiment, the compound of formula I is selected from the group of compounds of formulas I-1 and I-2:

wherein R ¹、R²、A¹、Z¹、Z², D, A, n and o have the meanings given for formula I above, and wherein the number of rings in the compound is at least 5,

And wherein preferably the first and second substrates are bonded together,

R ¹ and R ² are identical or different and represent H, N (R ^z)₂, a straight-chain alkyl radical having 1 to 12C atoms or a branched or cyclic alkyl radical having 3 to 18C atoms, where, in addition, one or more non-adjacent CH ₂ groups may each be, independently of one another, represented by-N (R ^z) -, -O-, -S-, -CO-, -CO-O-, -O-CO-or-O-CO-O-is replaced in such a way that O and/or S atoms are not directly connected to each other, and wherein, in addition, one or more H atoms may be replaced by F,

R ^z represents, identically or differently for each occurrence, H, a straight-chain alkyl radical having 1 to 12C atoms or a branched or cyclic alkyl radical having 3 to 12C atoms, where, in addition, one or more non-adjacent CH ₂ groups may be replaced by-O-, -S-, -CO-O-, O-CO-or-O-CO-O-is replaced in such a way that the O and/or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may be replaced by F,

Z ¹ and Z ² are the same or different and represent a single bond, -O-, -S-, a-C (O) -, -CF ₂O-、-OCF₂-、-C(O)-O-、-O-C(O)-、-OCH₂-、-CH₂ O-, -c≡c-, or-n=n-,

A ¹, which at each occurrence identically or differently, represents an aromatic, heteroaromatic, cycloaliphatic or heterocyclic radical having from 4 to 25 ring atoms, which may also comprise condensed rings, and which is unsubstituted or monosubstituted or polysubstituted by L,

L represents F, cl, -CN or a linear alkyl having 1 to 25C atoms or a branched or cyclic alkyl having 3 to 25C atoms, wherein one or more non-adjacent CH ₂ -groups are optionally replaced by-O-, -S-, -CO-O-, O-CO-or-O-CO-O-is replaced in such a way that O atoms and/or S atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by F,

D represents a heteroacenyl group comprising at least 4 fused rings, preferably consisting of at least 4 fused rings, wherein each ring may be unsubstituted or mono-or polysubstituted by L,

Wherein for formula I-2, if the group A does not contain any rings, the group D contains at least 5 fused rings,

A represents an acceptor group, preferably an electron-deficient moiety,

N represents 1, 2 or 3, preferably 1 or 2, more preferably 1, and

O represents 0 or 1, preferably 0.

In a preferred embodiment, in formulae I, I-1 and I-2 and for their preferred subformulae described herein, the group D is selected from the groups Da, db and Dc

Wherein Ar ¹、Ar²、Ar³、Ar⁴、Ar⁵ and Ar ⁶ represent condensed rings, an

Ar ¹ is independently selected from the following formula

Ar ⁴ is independently selected from the following formula

Ar ²、Ar³、Ar⁵、Ar⁶ is independently selected from the following formula

W ¹ is S, O or Se,

U ¹ is CR ^aR^b、SiR^aR^b、GeR^aR^b or NR ^a, wherein R ^a and R ^b are independently defined as R ⁴,

Wherein the radicals areOr (b)Not with another groupOr (b)The adjacent one of the two adjacent layers is,

R ⁴, R5, R6 and R7, which are identical or different for each occurrence, represent halogen or straight-chain alkyl or alkoxy having 1 to 20C atoms or branched-chain alkyl or alkoxy having 3 to 20C atoms, where one or more H atoms may be replaced by F,

In the ring represents a C atom shared by adjacent condensed rings, and

The single bond in groups Ar ¹ and Ar ⁴ represents the other groups to which groups Da, db and Dc are bonded.

In the present invention, in particular for the compounds of formula I, all atoms also include isotopes thereof. In particular, one or more hydrogen atoms (H) may be replaced by deuterium (D), which is particularly preferred in some embodiments, and highly deuterated so that analytical determination of the compound may be performed or simplified, especially at low concentrations.

Particularly preferably, for the compounds of the formulae I, I-1 and I-2 and for their preferred subformulae described herein, the group D is selected from the formulae

Wherein R ⁴, equal or different at each occurrence, represents halogen or straight-chain alkyl or alkoxy having 1 to 20C atoms or branched-chain alkyl or alkoxy having 3 to 20C atoms, wherein one or more H atoms may be replaced by F.

According to the invention, in the compounds of formula I, the chromophore system in the molecular structure consists of a combination of a donor group D directly adjacent to an acceptor group.

The acceptor group a herein is an electron-deficient moiety and may exhibit electron withdrawing properties. The acceptor group A is preferably a group having pi-electron deficient properties.

It has surprisingly been found that a specific combination of donor D and acceptor as described herein may yield benefits in dye performance, in particular in terms of extinction coefficient and reliability.

In one embodiment, the acceptor group A, in particular the electron withdrawing group A, is preferably selected from the group consisting of carbonyl and carbonyl-containing groups, sulfonyl and sulfonyl-containing groups, cyano and cyano-containing groups, nitro and nitro-containing groups, haloalkyl and haloalkyl-containing groups, electron-deficient aryl and electron-deficient aryl-containing groups, electron-deficient heteroaryl and electron-deficient heteroaryl-containing groups, benzothiadiazolyl, quinoxalinyl, in particular nitrile-containing quinoxalinyl, thiadiazoloquinoxalinyl, ruinyl, perylene, benzotriazole, anthraquinone, thiazolothiazole, bis (thiadiazolo) phenylene, pyridinyl and diketopyrrolopyrrole.

In a preferred embodiment, the radicals A of the formulae I, I-1 and I-2 and their preferred subformulae described herein are selected from the following formulae

Wherein the method comprises the steps of

R ⁸、R⁹、R¹⁰、R¹¹、R¹²、R¹³ and R ¹⁴, which are identical or different for each occurrence, represent H, halogen, CN or a straight-chain alkyl having 1 to 20C atoms or a branched alkyl having 3 to 20C atoms, where one or more H atoms can be replaced by F,

R ¹⁵ represents halogen, CN or a straight-chain alkyl having 1 to 20C atoms or a branched alkyl having 3 to 20C atoms, and

The dotted line indicates the bond to the remainder of the compound.

In one embodiment, the radicals A ¹ in formula I and its preferred subformulae are identically or differently selected from the group consisting of cycloaliphatic radicals, heterocyclic radicals, aryl radicals and heteroaryl radicals, which may be substituted by one or more radicals L as defined herein, preferably from the group consisting of 1, 4-cyclohexylene radicals, wherein one or two non-adjacent CH ₂ radicals may be replaced by O, 1, 4-cyclohexylene radicals, 1, 4-phenylene radicals, 1, 4-naphthylene radicals, 2, 6-naphthylene radicals, thiazole-2, 5-diyl radicals, thiophene-2, 5-diyl radicals, thienopyrrole-2, 5-diyl radicals, selenophene-2, 5-diyl radicals, thienopyrrole-2, 5-diyl radicals, dithienopyrrolediyl radicals, dithienopentacyclopentadienyl (dithienosiloldiyl), cyclopentanediphenyl radicals, pyridine-2, 5-diyl radicals, pyrimidinediyl radicals and pyridazinediyl radicals, wherein one or more H atoms may be replaced by a radical L as defined herein, preferably from the group consisting of 1, 4-phenylene radicals, 1, 4-naphthylene radicals, 2, 5-diyl radicals, thienopyrrole-2, 5-diyl radicals, dithienopyrrole radicals, dithiole-2, dithienopyrrole radicals, dithienyl radicals, dithienopene radicals (dithienosiloldiyl), cyclopentanediyl) and dithienyl radicals, cyclopentanediyl radicals, wherein L is preferably F.

In a preferred embodiment, the compound of formula I is selected from the group consisting of compounds of formula I-A

Wherein the number of rings in the compound is at least 5,

And

R ¹ represents H, N (R ^z)₂, a straight-chain alkyl group having 1 to 12C atoms or a branched or cyclic alkyl group having 3 to 18C atoms, wherein, in addition, one or more non-adjacent CH ₂ groups may each be, independently of one another, represented by-N (R ^z) -, -O-, -S-, -CO-, -CO-O-, -O-CO-or-O-CO-O-is replaced in such a way that O and/or S atoms are not directly connected to each other, and wherein, in addition, one or more H atoms may be replaced by F,

Preferably H, N (R ^z)₂, straight-chain alkyl having 1 to 12C atoms or branched or cyclic alkyl having 3 to 18C atoms, where, in addition, one or more non-adjacent CH ₂ groups can each independently of one another be replaced by-O-, where preferably R ^z, identically or differently on each occurrence, represents H, straight-chain alkyl having 1 to 12C atoms or branched or cyclic alkyl having 3 to 12C atoms,

R ^z represents, identically or differently for each occurrence, H, a straight-chain alkyl radical having 1 to 12C atoms or a branched or cyclic alkyl radical having 3 to 12C atoms, where, in addition, one or more non-adjacent CH ₂ groups may be replaced by-O-, -S-, -CO-O-, O-CO-or-O-CO-O-is replaced in such a way that the O and/or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may be replaced by F,

Z ¹ represents a single bond, -CF ₂O-、-OCF₂-、-C(O)-O-、-O-C(O)-、-OCH₂-、-CH₂ O-, -C≡C-, or-N=N-,

Preferably a single bond,

A ¹ represents identically or differently for each occurrence a 1, 4-cyclohexylene radical, in which one or two non-adjacent CH ₂ groups may be replaced by O, 1, 4-cyclohexenylene, 1, 4-phenylene, 1, 4-naphthylene, 2, 6-naphthylene, thiazole-2, 5-diyl, thiophene-2, 5-diyl, thienothiophene-2, 5-diyl, selenophene-2, 5-diyl, thienopyrrole-2, 5-diyl, dithienopyrroldiyl, dithienosyclopentadienyl, cyclopentadithiophene diyl, pyridine-2, 5-diyl, pyrimidinediyl or pyridazinediyl, in which one or more H atoms may be replaced by a group L,

L represents F, cl, -CN or a linear alkyl having 1 to 25C atoms or a branched or cyclic alkyl having 3 to 25C atoms, wherein one or more non-adjacent CH ₂ -groups are optionally replaced by-O-, -S-, -CO-O-, O-CO-or-O-CO-O-is replaced in such a way that O atoms and/or S atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by F,

D represents a heteroaromatic group comprising, preferably consisting of, at least 4 fused rings, wherein each ring may be unsubstituted or mono-or polysubstituted by L,

Wherein preferably, if n is 0, the group D comprises at least 5 fused rings,

A represents an acceptor group, preferably an electron-deficient moiety, and

N represents 0,1 or 2, preferably 0 or 1.

Particularly preferably, the compounds of formula I are selected from the group of compounds of the formula:

Wherein Alk represents unsubstituted or substituted alkyl or alternatively has the meaning as given for R ¹ of formula I, preferably straight-chain alkyl having 1 to 20C atoms or branched or cyclic alkyl having 3 to 20C atoms, more preferably straight-chain alkyl having 1 to 12C atoms or branched alkyl having 3 to 18C atoms.

In one embodiment, the compounds of formula I contain exactly one donor group and exactly one acceptor group, in particular selected from the group D and the group a, respectively, as defined herein.

Methods for preparing compounds of formula I may be based on or similar to known methods, e.g. as described in standard works of organic chemistry, such as e.g. Houben-Weyl, methoden der organischen Chemie [ organic chemistry methods (Methods of Organic Chemistry) ], THIEME VERLAG, stuttgart. Reference is additionally made to the examples and to the known literature for specific processes for the preparation of the compounds of the formula I.

In one aspect of the present invention, there is provided a process for preparing a compound of formula I, wherein in the process a bromine compound of formula I-Br is prepared or provided,

Wherein D, A, Z ²、A²、Q²、R² and o have the meanings as set forth herein for the compound of formula I, and wherein the compound of formula I-Br is subsequently subjected to a chemical reaction, preferably a cross-coupling reaction.

As described herein, the compounds of formula I exhibit advantageously large extinction coefficients, preferably in the visible spectrum and/or in the NIR spectrum, in particular in the visible spectrum.

In one embodiment, the compound of formula I has an isotropic extinction coefficient of at least 500 (wt% cm) ^-1, preferably at least 650 (wt% cm) ^-1, more preferably at least 800 (wt% cm) ^-1 and even more preferably at least 875 (wt% cm) ^-1.

The isotropic extinction coefficient is preferably determined according to the method as described further herein below.

A combination of high extinction coefficients, especially with high dichroism ratios, can yield several benefits. For example, a lower dye concentration may be used to achieve a desired contrast between a bright state and a dark state, i.e., between a relatively higher light transmittance state and a relatively lower light transmittance state, and to achieve an effective dark state. Smaller dye concentrations may also have benefits in terms of solubility or viscosity considerations. Likewise and also in combination, for the dye compounds of the present application having a high extinction coefficient, a single switching layer may be sufficient and/or a smaller switching layer thickness or cell gap may be sufficient to obtain the desired switching contrast and the desired dark state performance.

The compounds of the formula I are preferably orthodichromatic dyes, i.e. dyes having a positive degree of anisotropy R.

The degree of anisotropy R of the LC mixture containing the dye is determined from the extinction coefficient values of the molecules aligned parallel and perpendicular with respect to the polarization direction of the light.

According to the invention, the degree of anisotropy R is preferably greater than 0.4, more preferably greater than 0.6, even more preferably greater than 0.7, still more preferably greater than 0.75, and in particular greater than 0.8.

Absorption preferably achieves a maximum when the polarization direction of the light is parallel to the direction of elongation of the longest molecule of the compound of formula I, and a minimum when the polarization direction of the light is perpendicular to the direction of elongation of the longest molecule of the compound of formula I.

The compounds according to the invention preferably exhibit an absorption maximum at a wavelength in the visible or NIR spectrum, more preferably at a wavelength in the visible spectrum.

The compounds of the formula I can advantageously be used as guest compounds in liquid-crystalline host mixtures, in particular as dichroic dyes. Thus, in a preferred embodiment, the compound(s) of formula I are dissolved in an LC medium.

In one aspect of the invention, the mesogenic media comprises one or more compounds of formula I as set forth above and below, preferably two or more compounds of formula I as set forth above and below, more preferably three or more compounds of formula I as set forth above and below.

In a preferred embodiment, the mesogenic medium comprises at least one compound selected from the group of compounds of formulae I-1 and I-2 as set forth herein.

In a particularly preferred embodiment, the mesogenic media comprises at least one compound of formula I-a as set forth herein, more preferably at least two compounds of formula I-a as set forth herein.

In principle, a suitable host mixture is any dielectric negative or positive LC mixture suitable for use in conventional VA, TN, STN, IPS or FFS displays.

Suitable LC mixtures are known in the art and described in the references. LC media with negative dielectric anisotropy for VA displays are described, for example, in EP 1 378 557 A1.

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 195 28 107、WO 96/23 851、WO 96/28 521 and WO 2012/079676.

The following indicates preferred embodiments of liquid-crystalline media according to the invention having negative or positive dielectric anisotropy.

The LC host mixture is preferably a nematic LC mixture. In one embodiment, the LC mixture does not have a chiral LC phase.

In one embodiment of the invention, the LC medium contains an LC host mixture with negative dielectric anisotropy. Thus, in a preferred embodiment, the mesogenic medium according to the invention comprises a component selected from the following items a) to x):

a) A mesogenic medium comprising one or more compounds selected from the group of compounds of formulae CY, PY and AC:

Wherein the method comprises the steps of

A represents 0,1 or 2, preferably 1 or 2,

B represents 0 or 1, and the number of the groups is,

C is 0, 1 or 2,

D is 0 or 1.

Representation ofOr (b)

And

Representation of

Or (b)And (2) and

Representation of

R ¹ and R ²

R ^AC1 and R ^AC2 each independently of one another represent an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ 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 each other, preferably alkyl or alkoxy having 1 to 6C atoms,

Z ^x and Z ^y each independently of one another represent -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,

L ^1-4 each independently of one another represent F, cl, CN, OCF ₃、CF₃、CH₃、CH₂F、CHF₂.

Wherein the individual radicals have the following meanings:

Each independently of the others represents an alkyl group having 1 to 12C atoms, wherein, in addition, one or two non-adjacent CH ₂ 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 each other,

Z ^AC 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, and

Preferably, both L ¹ and L ² represent F, or one of L ¹ and L ² represents F and the other represents Cl, or both L ³ and L ⁴ represent F, or one of L ³ and L ⁴ represents F and the other represents Cl.

The compound of formula CY is preferably selected from the group consisting of the following subformulae:

Wherein a represents 1 or 2, alkyl and alkyl each independently of the other represent a linear alkyl group having 1 to 6C atoms, and alkinyl represents a linear alkenyl group having 2 to 6C atoms, and (O) represents an oxygen atom or a single bond. The alkinyl preferably represents CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

The compound of formula PY is preferably selected from the group consisting of the following subformulae:

Wherein alkyl and alkyl each independently represent a linear alkyl group having 1 to 6C atoms, and alkinyl represents a linear alkenyl group having 2 to 6C atoms, and (O) represents an oxygen atom or a single bond. The alkinyl preferably represents CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

The compound of formula AC is preferably selected from the group of compounds of the following subformulae:

b) A mesogenic medium, further comprising one or more compounds of the formula:

wherein the individual radicals have the following meanings:

Representation of

Or (b)

Representation ofOr (b)

R ³ and R ⁴ each independently of one another represent an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ 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 each other,

Z ^y 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.

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

Wherein alkyl and alkyl each independently of the other represent a linear alkyl group having 1 to 6C atoms, and alkyl represents a linear alkenyl group having 2 to 6C atoms. The alkinyl preferably represents CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

Particular preference is given to compounds of the formulae ZK1 and ZK 3.

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

wherein propyl, butyl and pentyl are straight chain groups.

Most preferred are compounds of formulae ZK1a and ZK3 a.

C) A mesogenic medium, further comprising one or more compounds of the formula:

Wherein the individual radicals have the following meanings identically or differently on each occurrence:

R ⁵ and R ⁶ each independently of one another represent an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ 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 each other, preferably alkyl or alkoxy having 1 to 6C atoms,

Representation ofOr (b)

Representation ofOr (b)And is also provided with

E represents 1 or 2.

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

Wherein alkyl and alkyl each independently of the other represent a linear alkyl group having 1 to 6C atoms, and alkyl represents a linear alkenyl group having 2 to 6C atoms. The alkinyl preferably represents CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

Preferred are compounds of formula DK1, DK4, DK7, DK9, DK10 and DK 11.

D) A mesogenic medium, further comprising one or more compounds of the formula:

wherein the individual radicals have the following meanings:

representation of

Or (b)

Wherein at least one ring F is different Yu Yahuan hexyl,

F represents a group consisting of 1 and 2,

R ¹ and R ² each independently of one another represent an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ 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 each other,

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,

L ¹ and L ² each independently of one another represent F, cl, OCF ₃、CF₃、CH₃、CH₂F、CHF₂.

Preferably, both groups L ¹ and L ² represent F or one of the groups L ¹ and L ² represents F and the other represents Cl.

The compound of formula LY is preferably selected from the group consisting of the following subformulae:

Wherein R ¹ has the meaning indicated above, alkyl represents a straight-chain alkyl group having 1 to 6C atoms, (O) represents an oxygen atom or a single bond, and v represents an integer of 1 to 6. R ¹ preferably represents a linear alkyl radical having 1 to 6C atoms or a linear alkenyl radical having 2 to 6C atoms, in particular CH₃、C₂H₅、n-C₃H₇、n-C₄H₉、n-C₅H₁₁、CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

E) A mesogenic medium further comprising one or more compounds selected from the group consisting of:

Wherein alkyl represents C _1-6 -alkyl, L ^x represents H or F, and X represents F, cl, OCF ₃、OCHF₂ or och=cf ₂. Particular preference is given to compounds of the formula G1 in which X denotes F.

F) A mesogenic medium further comprising one or more compounds selected from the group consisting of:

Wherein R ⁵ has one of the meanings indicated above for R ¹, alkyl represents C _1-6 -alkyl, d represents 0 or 1, and z and m each independently of one another represent an integer from 1 to 6. R ⁵ in these compounds is particularly preferably C _1-6 -alkyl or-alkoxy or C _2-6 -alkenyl, d preferably being 1. The LC medium according to the invention preferably comprises one or more compounds of the formula mentioned above in an amount of≥5% by weight.

G) A mesogenic medium further comprising one or more biphenyl compounds selected from the group consisting of the following formulas:

Wherein alkyl and alkyl each independently represent a linear alkyl group having 1 to 6C atoms, and alkyl each independently represent a linear alkenyl group having 2 to 6C atoms. alkinyl and alkinyl preferably represent CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

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

The compounds of the formula B2 are particularly preferred.

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

Wherein alkyl represents an alkyl group having 1 to 6C atoms. The medium according to the invention particularly preferably comprises one or more compounds of the formulae B1a and/or B2 c.

H) A mesogenic medium further comprising one or more terphenyl compounds of the formula:

wherein R ⁵ and R ⁶ each independently of the other have one of the meanings indicated above, and

And

Each independently of the other represent

Or (b)

Wherein L ⁵ represents F or Cl, preferably F, and L ⁶ represents F, cl, OCF ₃、CF₃、CH₃、CH₂ F or CHF ₂, preferably F.

The compound of formula T is preferably selected from the group consisting of the following subformulae:

Wherein R represents a linear alkyl group having 1 to 7C atoms or an alkoxy group, R represents a linear alkenyl group having 2 to 7C atoms, (O) represents an oxygen atom or a single bond, and m represents an integer of 1 to 6. R preferably represents CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

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

I) A mesogenic medium, further comprising one or more compounds of formula O:

Wherein the method comprises the steps of

Representation ofOr (b)

Representation of

Or (b)

R ^O1、R^O2 each independently of the other represents an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ 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 each other,

Z ^O1 represents-CH ₂CH₂-、-CF₂CF₂ -, -C=C-or a single bond,

Z ^O2 represents CH ₂O、-C(O)O-、-CH₂CH₂-、-CF₂CF₂ -or a single bond,

O is 1 or 2.

The compound of formula O is preferably selected from the group consisting of the following subformulae:

Wherein R ^O1 and R ^O2 have the meanings indicated above and preferably each independently of the other represent a linear alkyl group having 1 to 6C atoms or a linear alkenyl group having 2 to 6C atoms.

Preferred media comprise one or more compounds selected from the group consisting of formulas O3, O4 and O5.

K) A mesogenic medium, further comprising one or more compounds of the formula:

Wherein the method comprises the steps of

Representation of

R ⁹ represents H, CH ₃、C₂H₅ or n-C ₃H₇, (F) represents an optional fluorine substituent, and q represents 1,2 or 3, and R ⁷ has one of the meanings indicated for R ¹, preferably in an amount of > 3% by weight, in particular > 5% by weight and very particularly preferably from 5 to 30% by weight.

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

Wherein R ⁷ preferably represents a linear alkyl group and R ⁹ represents CH ₃、C₂H₅ or n-C ₃H₇. Particularly preferred are compounds of the formulae FI1, FI2 and FI 3.

L) a mesogenic medium, further comprising one or more compounds selected from the group consisting of:

Wherein R ⁸ has the meaning indicated for R ¹, and alkyl represents a straight-chain alkyl group having 1 to 6C atoms.

M) a mesogenic medium, which additionally comprises one or more compounds containing tetrahydronaphthyl or naphthyl units, such as, for example, compounds selected from the group consisting of the following formulae:

Wherein the method comprises the steps of

R ¹⁰ and R ¹¹ each independently of one another represent an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ 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 each other, preferably alkyl or alkoxy having 1 to 6C atoms,

And R ¹⁰ and R ¹¹ preferably represent a linear alkyl or alkoxy group having 1 to 6C atoms or a linear alkenyl group having 2 to 6C atoms, and

Z ¹ and Z ² each independently of one another represent -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.

N) a mesogenic medium, further comprising one or more difluorodibenzochromans and/or chromans of the formula:

Wherein the method comprises the steps of

R ¹¹ and R ¹² each independently of one another have one of the meanings indicated above for R ¹¹,

Ring M is trans-1, 4-cyclohexylene or 1, 4-phenylene,

Z ^m is-C ₂H₄-、-CH₂O-、-OCH₂ -; -CO-O-or-O-CO-,

C is 0, 1 or 2,

Preferably in an amount of 3 to 20% by weight, in particular in an amount of 3 to 15% by weight.

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

Wherein alkyl and alkyl each independently of the other represent a linear alkyl group having 1to 6C atoms, (O) represents an oxygen atom or a single bond, C is 1 or 2, and alkyl each independently of the other represent a linear alkenyl group having 2 to 6C atoms. alkinyl and alkinyl preferably represent CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

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

O) a mesogenic medium, which additionally comprises one or more fluorophenanthrene and/or dibenzofuran of the formula:

wherein R ¹¹ and R ¹² each independently of one another have one of the meanings indicated above for R ¹¹, b represents 0 or 1, l represents F, and R represents 1, 2 or 3.

Particularly preferred compounds of the formulae PH and BF are selected from the group consisting of the following subformulae:

wherein R and R' each independently of the other represent a linear alkyl or alkoxy group having 1 to 7C atoms.

In another embodiment, the liquid crystal medium comprises one or more compounds selected from the group of compounds of formulae B-1, B-2 and B-3:

Wherein the method comprises the steps of

R ¹¹ and R ¹² are identical or different and represent H or a linear alkyl or alkoxy radical having 1 to 15C atoms, wherein one or more CH ₂ groups in these radicals are optionally replaced, independently of one another, by-C.ident.C-; -CF ₂O-、-OCF₂ -, -ch=ch-,、 、-O-, -CO-O-, or-O-CO-is substituted in such a manner that O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen,

Preference is given to straight-chain alkoxy radicals having 1 to 7C atoms.

The compound of formula B-1 is preferably selected from the group of compounds of formulae B-1-a to B-1-e:

Wherein R ¹¹ and R ¹² are identical or different and represent an alkyl group having 1to 7C atoms, preferably ethyl, n-propyl, n-butyl or n-pentyl.

The compound of formula B-2 is preferably selected from the group of compounds of formulae B-2-a to B-2-e:

wherein R ¹¹ and R ¹² are the same or different and represent an alkyl group having 1 to 12C atoms, preferably an alkyl group having 1 to 7C atoms.

The compound of formula B-3 is preferably selected from the group of compounds of formulae B-3-a to B-3-j:

Wherein R ¹² represents an alkyl group having 1 to 7C atoms, preferably ethyl, n-propyl or n-butyl.

In A preferred embodiment, one or more compounds selected from the group of compounds of formulae B-1, B-2 and B-3 are selected from the group of compounds B-A to B-J:

One or more compounds selected from the group of compounds of formulae B-1, B-2 and B-3 are preferably contained in the liquid-crystalline medium in a total amount of 0to 15% by weight, more preferably 10% by weight or less and even more preferably 5% by weight or less.

P) a mesogenic medium, further comprising one or more mono-cyclic compounds of the formula:

Wherein the method comprises the steps of

R ¹ and R ² each independently of one another represent an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ 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 each other, preferably alkyl or alkoxy having 1 to 6C atoms,

L ¹ and L ² each independently of one another represent F, cl, OCF ₃、CF₃、CH₃、CH₂F、CHF₂.

Preferably, L ¹ and L ² both represent F, or one of L ¹ and L ² represents F and the other represents Cl,

The compound of formula Y is preferably selected from the group consisting of the following subformulae:

Wherein, alkyl and Alkyl each independently of the other represent a linear Alkyl group having 1 to 6C atoms, alkoxy represents a linear alkoxy group having 1 to 6C atoms, alkenyl and Alkenyl each independently of the other represent a linear alkenyl group having 2 to 6C atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl preferably represent CH₂=CH-、CH₂=CHCH₂CH₂-、CH₃-CH=CH-、CH₃-CH₂-CH=CH-、CH₃-(CH₂)₂-CH=CH-、CH₃-(CH₂)₃-CH=CH- or CH ₃-CH=CH-(CH₂)₂ -.

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

wherein Alkoxy preferably represents a linear alkoxy group having 3,4 or 5C atoms.

Q) a mesogenic medium comprising 1 to 15, preferably 3 to 12 compounds of formula CY1, CY2, PY1, PY2, AC1, AC2 and/or AC 3. The proportion of these compounds in the mixture as a whole is preferably from 20 to 99%, more preferably from 30 to 95%, particularly preferably from 40 to 90%. The content of such individual compounds is preferably from 2 to 20% in each case.

R) a mesogenic medium comprising 1 to 10, preferably 1 to 8, compounds of formula ZK, in particular compounds of formulae ZK1, ZK2 and/or ZK 6. The proportion of these compounds in the mixture as a whole is preferably 3 to 25%, particularly preferably 5 to 45%. The content of such individual compounds is preferably from 2 to 20% in each case.

S) a mesogenic medium, wherein the proportion of the compounds of formulae CY, PY and ZK in the mixture as a whole is greater than 70%, preferably greater than 80%.

T) a mesogenic medium comprising one or more, preferably 1 to 5, compounds selected from the group of compounds of formulae PY1 to PY8, very preferably compounds of formula PY 2. The proportion of these compounds in the mixture as a whole is preferably from 1 to 30%, particularly preferably from 2 to 20%. The content of such individual compounds is preferably in each case from 1 to 20%.

U) a mesogenic medium comprising one or more, preferably 1, 2 or 3, compounds of formula T2. The content of these compounds in the mixture as a whole is preferably 1 to 20%.

The LC medium according to the invention preferably comprises terphenyl of formula T and its preferred subformulae in an amount of 0.5 to 30% by weight, in particular 1 to 20% by weight.

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

If the Δn value of the mixture is to be brought to > 0.1, terphenyl is preferably used in the mixture according to the invention. Preferred mixtures comprise from 2 to 20% by weight of one or more terphenyl compounds of the formula T, preferably selected from the group of compounds T1 to T22.

V) a mesogenic medium comprising one or more, preferably 1,2 or 3, compounds of formula BF1 and/or BSF 1. The total content of these compounds in the mixture is preferably from 1 to 15%, preferably from 2 to 10%, particularly preferably from 4 to 8%.

W) the preferred medium comprises one or more compounds of the formula O, preferably selected from the group consisting of compounds of the formulae O3, O4 and O5, in a total concentration of from 2 to 25%, preferably from 3 to 20%, particularly preferably from 5 to 15%.

X) preferred media comprise one or more compounds of formula DK, preferably selected from compounds of formulae DK1, DK4, DK7, DK9, DK10 and DK 11. The total concentration of compounds of the formulae DK9, DK10 and DK11 is preferably 2 to 25%, more preferably 3 to 20%, particularly preferably 5 to 15%.

In another embodiment of the invention, the LC medium contains an LC host mixture with positive dielectric anisotropy. Thus, in other preferred embodiments, the mesogenic media according to the invention comprise a component selected from the following items aa) to zz):

aa) a mesogenic medium comprising one or more compounds selected from the group of compounds of formulae II to VIII as set forth below, in particular compounds of formulae II and III:

Wherein the method comprises the steps of

R ²⁰ each identical or different represents a halogenated or unsubstituted alkyl or alkoxy radical having 1 to 15C atoms, where, in addition, one or more CH ₂ groups in such radicals may each, independently of one another, be replaced by-C.ident.C-, -CF ₂ O-, -ch=ch-, -O-, -CO-O-, or-O-CO-is replaced in such a way that O atoms are not directly connected to each other,

X ²⁰ each identically or differently represents F, cl, CN, SF ₅, SCN, NCS, haloalkyl, haloalkenyl, haloalkoxy or haloalkenoxy, each having up to 6C atoms, and

Y ^20-24 each independently represents H or F, identically or differently;

And Each independently of the other represent

Or (b)。

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

wherein R ²⁰ and X ²⁰ have the meanings indicated above.

R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X ²⁰ preferably represents F. Particular preference is given to compounds of the formulae IIa and IIb, in particular of the formulae IIa and IIb, in which X denotes F.

In one embodiment, the liquid crystal medium comprises one or more compounds selected from the group of compounds of formulas II-1 and II-2:

Wherein the method comprises the steps of

R ² represents alkyl, alkoxy, fluoroalkyl or fluoroalkoxy having 1 to 7C atoms or alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2 to 7C atoms,

Wherein optionally one or more CH ₂ groups may be used independently of one another、、、Or (b)Instead of this, the first and second heat exchangers,

AndIndependently of one another are

Or (b),

L ²¹、L²²、L²³ and L ²⁴ independently of one another represent H or F,

L ²⁵ represents H or CH ₃, and

X ² represents halogen, haloalkyl or alkoxy having 1 to 3C atoms or haloalkenyl or alkenyloxy having 2 or 3C atoms.

In another embodiment, the liquid-crystalline medium comprises one or more compounds selected from the group of compounds of formulae II-1-a to II-1-h:

Wherein R ² has the meaning as given in formula II-1.

In another embodiment, the liquid-crystalline medium comprises one or more compounds selected from the group consisting of compounds of formulae II-2-a to II-2-l:

Wherein R ² has the meaning given for formula II-2 above.

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

wherein R ²⁰ and X ²⁰ have the meanings indicated above.

R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X ²⁰ preferably represents F. Particularly preferred are compounds of formulae IIIa and IIIe, in particular of formula IIIa;

bb) alternatively or additionally a mesogenic medium comprising one or more compounds selected from the group consisting of the following formulae:

Wherein the method comprises the steps of

R ²⁰、X²⁰ and Y ^20-23 have the meanings indicated above, and

Z ²⁰ represents -C₂H₄-、-(CH₂)₄-、-CH=CH-、-CF=CF-、-C₂F₄-、-CH₂CF₂-、-CF₂CH₂-、-CH₂O-、-OCH₂-、-COO- or-OCF ₂ -, in which case a single bond is also present in formulae V and VI and-CF ₂ O-, in formulae V and VIII,

R represents 0 or 1, and

S represents 0 or 1;

-the compound of formula IV is preferably selected from the following formulae:

wherein R ²⁰ and X ²⁰ have the meanings indicated above.

R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X ²⁰ preferably represents F, CN or OCF ₃, and also ocf=cf ₂ or Cl;

-the compound of formula V is preferably selected from the following formulae:

wherein R ²⁰ and X ²⁰ have the meanings indicated above.

R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X ²⁰ preferably represents F and OCF ₃, and further represents OCHF ₂、CF₃、OCF=CF₂ and och=cf ₂;

-the compound of formula VI is preferably selected from the following formulae:

wherein R ²⁰ and X ²⁰ have the meanings indicated above.

R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X ²⁰ preferably represents F, further OCF ₃、CF₃、CF=CF₂、OCHF₂ and och=cf ₂;

-the compound of formula VII is preferably selected from the following formulae:

wherein R ²⁰ and X ²⁰ have the meanings indicated above.

R ²⁰ preferably represents an alkyl group having 1to 6C atoms. X ²⁰ preferably represents F, and also OCF ₃、OCHF₂ and och=cf ₂.

Cc) a mesogenic medium, further comprising one or more compounds selected from the formulae ZK1 to ZK10 given above. Especially preferred are compounds of formulae ZK1 and ZK 3. Particularly preferred compounds of the formula ZK are selected from the subformulae ZK1a, ZK1b, ZK1c, ZK3a, ZK3b, ZK3c and ZK3d.

Dd) the mesogenic media additionally comprises one or more compounds selected from the formulae DK1 to DK12 given above. Particularly preferred compounds are DK1, DK4, DK7, DK9, DK10 and DK11.

Ee) the mesogenic medium additionally comprises one or more compounds selected from the group consisting of:

Wherein X ²⁰ has the meaning indicated above,

L represents H or F, and

"Alkinyl" means C _2-6 -alkenyl.

Ff) the compounds of formulae DK-3a and IX are preferably selected from the following formulae:

Wherein "alkyl" denotes C _1-6 -alkyl, preferably n-C ₃H₇、n-C₄H₉ or n-C ₅H₁₁, in particular n-C ₃H₇.

Gg) the medium additionally 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, B2B and B2c.

Hh) the medium additionally comprises one or more compounds selected from the group consisting of:

Wherein L ²⁰、L²¹ represents H or F, and R ²¹ and R ²² each identically or differently represent n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6C atoms, and preferably each identically or differently represent alkyl having 1 to 6C atoms.

Ii) the medium comprises one or more compounds of the formula:

Wherein R ²⁰、X²⁰ and Y ^20-23 have the meanings indicated in formula III, and

AndEach independently of the other represent

Or (b)

And

Representation of

Or (b)。

The compounds of formulae XI and XII are preferably selected from the following formulae:

Wherein R ²⁰ and X ²⁰ have the meanings indicated above and preferably R ²⁰ represents an alkyl group having 1to 6C atoms and X ²⁰ represents F.

The mixtures according to the invention particularly preferably comprise at least one compound of the formulae XIIa and/or XIie.

Jj) the medium comprises one or more compounds of the formula T given above, preferably selected from the group of compounds of the formulae T21 to T23 and T25 to T27.

Particularly preferred are compounds of the formulae T21 to T23. Very particular preference is given to compounds of the formula:

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

Ll) the medium additionally comprises one or more compounds selected from the group consisting of the following formulae:

Wherein R ²⁰ and X ²⁰ each have, independently of one another, one of the meanings indicated above, and Y ^20-23 each represent, independently of one another, H or F. X ²⁰ is preferably F, cl, CF ₃、OCF₃ or OCHF ₂.R²⁰ preferably represents alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, each having up to 6C atoms.

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

Wherein R ²⁰ has the meaning indicated above. R ²⁰ preferably represents a linear alkyl radical, in particular ethyl, n-propyl, n-butyl and n-pentyl and very particularly preferably n-propyl. The compounds of the formula XVIII, in particular of the formula XVIII-a, are preferably used in the mixtures according to the invention in amounts of from 0.5 to 20% by weight, particularly preferably from 1 to 15% by weight.

Mm) the medium additionally comprises one or more compounds of the formula XIX,

Wherein R ²⁰、X²⁰ and Y ^20-25 have the meanings indicated in formula III, s represents 0 or 1, and

Representation ofOr (b)。

In formula XIX, X ²⁰ may also represent an alkyl group having 1 to 6C atoms or an alkoxy group having 1 to 6C atoms. The alkyl or alkoxy group is preferably straight chain.

R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X ²⁰ preferably represents F;

-the compound of formula XIX is preferably selected from the following formulae:

Wherein R ²⁰、X²⁰ and Y ²⁰ have the meanings indicated above. R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X ²⁰ preferably represents F, and Y ²⁰ preferably is F;

- Preferably is

Or (b)

-R ²⁰ is a linear alkyl or alkenyl group having 2 to 6C atoms.

Nn) the medium comprises one or more compounds of the formulae G1 to G4 given above, preferably selected from the group consisting of G1 and G2 compounds, wherein alkyl represents C _1-6 -alkyl, L ^x represents H, and X represents F or Cl. In G2, X particularly preferably represents Cl.

Oo) the medium comprises one or more compounds of the formula:

Wherein R ²⁰ and X ²⁰ have the meanings indicated above. R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X 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 denotes F. The compounds of the formulae XX to XXII are preferably used in the mixtures according to the invention in amounts of from 1 to 20% by weight, particularly preferably from 1 to 15% by weight. Particularly preferred mixtures comprise at least one compound of the formula XXII.

Pp) the medium comprises one or more compounds of the formula pyrimidine or pyridine compounds,

Wherein R ²⁰ and X ²⁰ have the meanings indicated above. R ²⁰ preferably represents an alkyl group having 1 to 6C atoms. X ²⁰ preferably represents F. The medium according to the invention particularly preferably comprises one or more compounds of the formula M-1, wherein X ²⁰ preferably denotes F. The compounds of the formulae M-1 to M-3 are preferably used in the mixtures according to the invention in amounts of from 1 to 20% by weight, particularly preferably from 1 to 15% by weight.

Qq) the medium comprises two or more compounds of the formula XII, in particular of the formula XIIa and/or XIie.

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.

Ss) in addition to the compound of formula XII, the medium comprises further compounds from the group of compounds of formulae II to XVIII.

Tt) the proportion of the compounds of the formulae II to XVIII in the mixture as a whole is from 40 to 95% by weight, preferably from 50 to 90% by weight, particularly preferably from 55 to 88% by weight.

Uu) the medium preferably contains 10 to 40% by weight, more preferably 12 to 30% by weight, particularly preferably 15 to 25% by weight, of compounds of the formulae II and/or III.

V) the medium contains from 1 to 10% by weight, particularly preferably from 2 to 7% by weight, of compounds of the formulae XV and/or XVI.

Ww) the medium comprises at least one compound of the formula XIIa and/or at least one compound of the formula XIie and at least one compound of the formula IIIa and/or IIa.

Xx) the preferred medium comprises one or more compounds of the formula O, preferably selected from compounds of the formulae O3, O4 and O5, in a total concentration of from 2 to 25%, preferably from 3 to 20%, particularly preferably from 5 to 15%.

Yy) preferred media comprise one or more compounds of formula DK, preferably selected from compounds of formulae DK1, DK4, DK7, DK9, DK10 and DK 11. The total concentration of compounds of the formulae DK9, DK10 and DK11 is preferably 2 to 25%, more preferably 3 to 20%, particularly preferably 5 to 15%.

Zz), preferably one or more compounds of the formulae IV to VI, preferably selected from the group of compounds of the formulae IVa, IVb, IVc, IVd, va, vc and VIb, are contained in a concentration of 10 to 80% by weight, preferably 12 to 75% by weight, particularly preferably 15 to 70% by weight.

In the case of a medium having negative dielectric anisotropy, the value of the dielectric anisotropy (. DELTA.. Epsilon.) is preferably in the range of-2.0 to-8.0, more preferably in the range of-3.0 to-6.0, and particularly preferably in the range of-3.5 to-5.0.

In the case of a medium having positive dielectric anisotropy, the value of Δεis preferably in the range of 2.5 to 50.0, more preferably in the range of 5.0 to 25.0, and particularly preferably in the range of 8.0 to 15.0.

The liquid-crystalline medium according to the invention preferably has a clearing point of 70 ℃ or more, more preferably 80 ℃ or more, even more preferably 90 ℃ or more, still more preferably 105 ℃ or more, and particularly preferably 110 ℃ or more. In one embodiment, the liquid-crystalline medium according to the invention has a clearing point in the range from 70 ℃ to 170 ℃.

High definition bright spots as defined herein may be advantageous in terms of performance and reliability of devices using liquid crystal media. In particular, the medium can maintain its functional properties over a suitably broad temperature range and also at high temperatures. This may be particularly advantageous for use in window elements that regulate the passage of sunlight, especially when the window element is exposed to direct or prolonged irradiation of sunlight. This Gao Qingliang point may also contribute to an advantageous high degree of ordering of the liquid crystal host molecules and thus to ordering of the dichroic dye guest molecules at typical operating temperatures, which may increase the contrast obtainable between switching states.

The clearing point, in particular the phase transition temperature between nematic and isotropic phases, can be measured and determined by generally known methods, for example using a Mettler (Mettler) oven, a heat stage under a polarizing microscope or Differential Scanning Calorimetry (DSC) analysis. According to the invention, the clearing point is preferably determined using a mertler oven.

The nematic phase of the medium according to the invention preferably extends at least from-10 ℃ or less to 80 ℃ or more. Even more broad nematic phase ranges are more preferred, in particular extending up to 90 ℃ or more, more preferably at least from-20 ℃ or less to 100 ℃ or more and particularly preferably from-30 ℃ or less to 110 ℃ or more.

In a preferred embodiment of the invention, the birefringence (Δn) of the liquid crystalline medium is in the range of 0.010 or more to 0.350 or less, more preferably in the range of 0.035 or more to 0.300 or less, even more preferably in the range of 0.050 or more to 0.250 or less, still more preferably in the range of 0.075 or more to 0.200 or less, and especially in the range of 0.010 or more to 0.150 or less.

The compounds selected from the group of compounds of formula I as set forth above and below are preferably present in the mesogenic medium in a proportion of from 0.01 to 15 wt.%, more preferably from 0.025 to 10 wt.%, even more preferably from 0.05 to 7.5 wt.%, yet more preferably from 0.1 to 5 wt.%, and in particular from 0.2 to 2 wt.%. In a specific embodiment, the dye compounds according to the invention are present in the medium in a concentration in the range of 0.05% to 1% by weight.

In one embodiment in which two or more compounds selected from the group of compounds of formula I as set forth above and below are present in the mesogenic medium, the total concentration of these compounds in the medium is particularly preferably in the range from 0.05 to 15% by weight and even more preferably from 0.1 to 10% by weight, and in particular from 0.2 to 5% by weight. In this case, it is particularly preferred that the individual dye compounds are present in the medium in a concentration in the range from 0.025% to 5% by weight and even more preferably from 0.05% to 2.5% by weight and in particular from 0.1% to 1% by weight.

The medium preferably comprises one, two, three, four, five, six, seven, eight or nine compounds of the formula I according to the invention. In a specific embodiment, the medium comprises at least three compounds selected from the group of compounds of formulas I-1 and I-2.

The LC medium according to the invention is preferably a nematic liquid crystal.

The media according to the invention are prepared in a manner conventional per se. In general, the components are dissolved in each other, preferably at an elevated temperature. The mixing is preferably carried out under an inert gas, for example under nitrogen or argon. The addition of one or more dyes of the formula I and optionally further dichroic dyes is then carried out, preferably at elevated temperature, more preferably above 40 ℃ and particularly preferably above 50 ℃. In general, a desired amount of a component used in a smaller amount is dissolved in a component constituting the main ingredient. It is also possible to mix solutions of the components in organic solvents, for example in acetone, toluene, chloroform or methanol, and to remove the solvent again after mixing, for example by distillation.

The invention also relates to a method for preparing a mesogenic medium according to the invention.

The invention also relates to the use of LC media comprising at least one compound of formula I in a liquid crystal device of the guest-host type, wherein the device is in particular a window assembly or a display. In this device, the compound according to the invention and the medium are preferably arranged in one or more switching layers.

In a preferred embodiment, the device, in particular a window, contains only a single switching layer.

The invention furthermore relates to a liquid crystal display of the guest-host type, which contains an LC medium comprising at least one compound of the formula I.

The invention also relates to the use of a mixture comprising a liquid-crystalline medium and at least one compound of formula I in a device for regulating the passage of energy through an external space into an internal space.

In a specific embodiment, the device according to the invention preferably comprises, in addition to one or more compounds selected from the group of compounds of formula I, and preferably a liquid crystalline medium, further dichroic dyes having a structure different from that of formula I in the switching layer. It particularly preferably comprises one, two, three, four, five, six, seven or eight other dyes, most preferably two or three other dyes having a different structure than formula I.

Regarding the nature of dichroism, the preferred properties described for the compounds of formula I are also preferred for the optional further dichromatic dyes.

The absorption spectra of the dichroic dyes of the switching layer are preferably complementary to each other in such a way that the eye gives the impression of a black or respectively grey or neutral appearance. Preferably two or more dichroic dyes of the liquid crystal medium according to the invention cover preferably a large part of the visible spectrum, more preferably the entire visible spectrum. The exact method by which mixtures of dyes exhibiting a black or gray color to the eye can be prepared is known in the art and described, for example, in M.Richter, einfu hrung in die Farbmetrik [ colorimetry guidance (Introduction to Colorimetry) ], 2 nd edition, 1981, ISBN 3-11-008209-8, walter de Gruyter & Co.

The setting of the color position of mixtures of dyes is described in the field of colorimetry. To this end, the spectra of the individual dyes are calculated in view of Lambert-Beer law to produce an overall spectrum and are converted into corresponding color positions and luminance values under the relevant illumination (e.g. light source D65 of daylight) according to the rules of colorimetry. The location of the white point is fixed by the corresponding light source (e.g., D65) and is referenced in the table (e.g., in the above references). Different color positions can be set by changing the ratio of the various dyes.

According to a preferred embodiment, the switching layer comprises one or more dichroic dyes which absorb light in the red and NIR region, i.e. at wavelengths in the range 600 nm to 2000 nm, preferably in the range 600 nm to 1800 nm, particularly preferably in the range 650 nm to 1300 nm.

In a preferred embodiment, the mesogenic medium further comprises at least one dichroic dye in addition to the compound of formula I. Preferably, such other dichroic dye or dyes are selected from azo dyes, anthraquinones, methine compounds, azo methine compounds, merocyanine compounds, naphthoquinones, tetrazines, perylenes, bicarproperties (terylenes), bicarproperties (quaterylenes), higher alcohols, pyrromethenes, thiadiazoles, benzothiadiazoles, nickel dithioenes (nickel dithiolenes), (metal) phthalocyanines, (metal) naphthalocyanines and (metal) porphyrins. Among them, azo dyes, thiadiazoles and benzothiadiazoles are particularly preferable.

In one embodiment, the further dichroic dye preferably provided in the switching layer having a structure different from formula I is preferably selected from the dye classes indicated in b. Bahadur, liquid Crystals-Applications and Uses, volume 3, 1992, world Scientific Publishing, chapter 11.2.1, and particularly preferably from the specific compounds given in the tables presented therein.

The dyes fall into the category of dichroic dyes known in the art and described in the references. Thus, for example, anthraquinone dyes are described in EP 34832、EP 44893、EP 48583、EP 54217、EP 56492、EP 59036、GB 2065158、GB 2065695、GB 2081736、GB 2082196、GB 2094822、GB 2094825、JP-A 55-123673、DE 3017877、DE 3040102、DE 3115147、DE 3115762、DE 3150803 and DE 3201120, naphthoquinone dyes in DE 3126108 and DE 3202761, azo dyes in EP 43904、DE 3123519、WO 82/2054、GB 2079770、JP-A 56-57850、JP-A 56-104984、US 4308161、US 4308162、US 4340973、T. Uchida、C. Shishido、H. Seki and M.Wada: mol. Cryst. Lig. Cryst. 39, 39-52 (1977), and H.Seki, C. Shishido, S. Yasui and T.Uchida: jpn. J. Appl. Phys. 21, 191-192 (1982), and perylene in EP 60895, EP 68427 and WO 82/1191. Rui dyes are described, for example, in EP 2166040, U.S. Pat. No. 5,2011/0042651, EP 68427, EP 47027, EP 60895, DE 3110960 and EP 698649.

Examples of preferred other dichroic dyes that may be present in the switching layer of the device are shown below,

In a particularly preferred embodiment, the mesogenic media further comprises at least one compound selected from the group of compounds of the formula,

In a specific embodiment, the medium according to the invention comprises one or more quencher compounds. It is preferred if the device according to the invention comprises one or more fluorescent dyes in the switching layer.

The quencher compound is a compound that quenches fluorescence. The quencher compound may absorb electron excitation energy of adjacent molecules (such as, for example, fluorescent dyes) in the switching layer and undergo a transition to an electron excited state in the process. The fluorescent dye to be quenched is thus converted into an electron ground state and is thus prevented from emitting fluorescence or undergoing a subsequent reaction. The quencher compound itself is deactivated by no radiation or returned to the ground state by emitted light and can be used again for further quenching.

The quencher compound may have various functions in the medium and switching layer of the device according to the invention. First, deactivation of the quencher compound by electron excitation energy may help to extend the lifetime of the dye system. Second, the quencher compound may eliminate an aesthetically undesirable additional color effect, such as colored emissions from the fluorescent dye in the switching layer in the interior space.

To achieve efficient quenching, the quencher compound should be adapted to the corresponding dye system, in particular the dye absorbed at the longest wavelength in the dye combination. Methods of carrying out this scheme are known in the art.

Preferred quencher compounds are described, for example, in J.R. Lakowicz, PRINCIPLES OF FLUORESCENCE SPECTROSCOPY, 3 rd edition, 2010, ISBN 10:0-387-31278-1, SPRINGER SCIENCE + Business Media LLC, on page 279, table 8.1. Other classes of compounds, such as so-called dark quenchers or black hole quenchers, are known in the art. Examples include azo dyes and aminoanthraquinone. The quencher compounds used in the switching layer of the device according to the invention may also be non-fluorescent dyes or dyes that fluoresce only in the NIR.

In a preferred embodiment of the switching layer according to the invention, any quencher compound present is selected such that fluorescence in the visible part of the spectrum is suppressed.

The device according to the invention is preferably adapted to regulate the passage of energy in the form of sunlight from the environment into the interior space. The energy to be conditioned here passes from the environment (i.e. the external space) into the internal space.

The interior space herein may be any desired space that is substantially isolated from the environment, such as a building, vehicle, or container.

The invention thus furthermore relates to the use of a device for regulating the passage of energy through an external space into an internal space.

However, the device may also be used for indoor aesthetic designs, for example for light and color effects. For example, door and wall elements containing devices according to the invention in gray or in color can be switched transparent. In addition, the device may also include a white or color flat panel backlight to adjust brightness, or a yellow flat panel backlight to adjust color via a blue guest-host display. In the case of glass substrates used in the device, one or both sides of the device according to the invention may be provided with roughened or structured glass for coupling out light and/or for producing light effects.

The liquid-crystalline medium according to the invention is therefore preferably used in architectural windows or in automobiles, for example in sunroofs. In particular, the switchable optical device may be included in a window or facade of a building. The device according to the invention is also applicable to commercial vehicles, ships, trains or aircraft.

In another alternative use, the device is used to condition light incident on the eye, for example in goggles, visors or sunglasses, wherein the device maintains low light incident on the eye in one switching state and reduces light incidence to a lesser extent in the other switching state.

The device according to the invention is preferably arranged in an opening in a relatively large two-dimensional structure, wherein the two-dimensional structure itself allows only a slight passage of energy or does not allow it at all, and wherein the opening has a relatively high energy transmission. The two-dimensional structure is preferably a wall or another boundary of the interior space with the outside. Furthermore, the two-dimensional structure preferably covers an area of at least equal size, particularly preferably at least twice as much as the area in which the opening of the device according to the invention is provided.

The device is preferably characterized in that it has an area of at least 0.05 m ², preferably at least 0.1 m ², particularly preferably at least 0.5m ² and very particularly preferably at least 1.0 m ². For windows containing the device, the device area is preferably in the range of 0.1 m ² to 10m ², more preferably 0.5m ² to 5m ², and especially 1m ² to 3m ².

The device is preferably housed in an opening having a relatively high energy transmission, as described above, in a building, container, vehicle, or another substantially enclosed space. The device can generally be used for any desired interior space, in particular if it has only a limited exchange of air with the environment and has a light-transmitting boundary surface, through which energy input in the form of light energy from the outside can take place. The use of the device is particularly preferred for interior spaces that are subjected to intense sun exposure through light-transmitting areas, such as through window areas.

The device according to the invention is switchable. Switching here refers to the change in energy passed through by the device. The device according to the invention is preferably electrically switchable as described for example in WO 2009/141295 and WO 2014/090373.

However, the device may also be thermally switchable, as described for example in WO 2010/118422. In this case, the switching is preferably carried out by switching from the nematic state to the isotropic state via a change in temperature of the switching layer comprising the compound of the formula I and the liquid-crystalline medium. In the nematic state, the molecules of the liquid-crystalline medium and thus the compounds of the formula I are also in ordered form, for example aligned parallel to the device surface by the action of an alignment layer. In the isotropic state, the molecule is in a disordered form, and thus the compound of formula I is also in a disordered form. The difference between ordered and disordered presence of the dichroic compound causes a difference in light transmittance of the switching layer of the device according to the invention, based on the principle that the dichroic compound will have a higher or lower absorption coefficient depending on the alignment with respect to the plane of polarization of the light.

Where the device is electrically switchable, it preferably comprises two or more electrodes, preferably mounted on both sides of the switching layer. The electrode is preferably composed of ITO or a thin, preferably transparent, metal and/or metal oxide layer, such as silver or FTO (fluorine doped tin oxide) or alternative materials known in the art for this purpose. The electrodes are preferably provided with electrical connections. The voltage is preferably provided by a battery, a rechargeable battery or an external power source, in particular an external power source.

In the case of electrical switching, the switching operation is carried out by (re) aligning the molecules of the liquid crystal medium by applying a voltage.

In one embodiment, the device transitions from a state with high absorption (i.e., low light transmittance) to a state with lower absorption (i.e., higher light transmittance) that exists in the absence of a voltage. The liquid-crystalline medium of the switching layer is preferably nematic in both states. The voltage-free state is preferably characterized by the molecules of the liquid-crystalline medium (and thus of the compound of formula I) being aligned parallel to the plane of the switching layer. This is preferably achieved by a correspondingly selected alignment layer. The state of the applied voltage is preferably characterized in that the molecules of the liquid crystal medium (and thus of the compound of formula I) are perpendicular to the plane of the switching layer.

In an alternative embodiment, the device may switch from a state with low absorption (i.e., high light transmittance) to a state with higher absorption (i.e., lower light transmittance) that exists in the absence of a voltage. The liquid-crystalline medium of the switching layer is preferably nematic in both states. The voltage-free state is preferably characterized by the molecules of the liquid-crystalline medium of the switching layer (and thus of the compound of formula I) being aligned perpendicular to the plane of the switching layer. This is preferably achieved by a correspondingly selected alignment layer. The state of the applied voltage is preferably characterized in that the molecules of the liquid crystal medium of the switching layer (and thus of the compound of formula I) are parallel to the plane of the switching layer.

The device according to the invention preferably has the following layer sequence, wherein further layers may additionally be present. The layers indicated below are preferably directly adjacent to each other in the device:

-a substrate layer, preferably comprising glass or a polymer

An electrically conductive transparent layer, preferably comprising ITO

Alignment layer

A switching layer comprising one or more compounds of formula I

Alignment layer

An electrically conductive transparent layer, preferably comprising ITO

-A substrate layer, preferably comprising glass or a polymer.

In another embodiment, the device contains two switching layers, which may be arranged in a so-called double cassette.

The device according to the invention preferably comprises one or more (particularly preferably two) alignment layers. The alignment layer is preferably directly adjacent to both sides of the switching layer comprising the compound of formula I.

The alignment layer used in the device according to the invention may be any desired layer known to the person skilled in the art for this purpose. Polyimide layers are preferred, and particularly preferred are those comprising rubbed polyimide. In one embodiment, a planar alignment is provided, wherein a slight pretilt angle may be more preferably set. In an alternative embodiment, a vertical alignment is provided, wherein a high pretilt angle is more preferably set.

In addition, a polymer obtained by an exposure method to polarized light may be used as an alignment layer to achieve alignment of a compound of a liquid crystal medium according to an alignment axis (i.e., photoalignment).

The switching layer in the device according to the invention is even more preferably arranged between two substrate layers or enclosed thereby. The substrate is preferably optically transparent. The substrate layer may for example consist of glass or a polymer, preferably a light transmitting polymer.

Suitable glass substrates include, for example, float glass, drop down glass, chemically or thermally treated tempered glass, borosilicate glass, and aluminosilicate glass.

Suitable polymeric substrates include, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polycarbonate (PC), polyimide (PI), COP (cyclic olefin polymer), and cellulose Triacetate (TAC).

The two substrates are arranged as one cassette, wherein a gap is formed by the two substrates. The size of the gap, or the thickness of the switching layer, respectively, is preferably 1 μm to 100 μm, preferably 2 μm to 50 μm and more preferably 3 μm to 25 μm, and most preferably 5 μm to 10 μm. The box is typically sealed by means of glue lines at or near the edges. In a preferred embodiment, the cell gap is 25 μm or less, preferably 10 μm or less, and more preferably 6 μm or less.

The device is preferably characterized in that it does not comprise a polymer-based polarizer, particularly preferably does not comprise a polarizer in the solid material phase and very particularly preferably does not comprise a polarizer at all.

However, according to an alternative embodiment, the device may also comprise one or more polarizers. In which case the polarizer is preferably a linear polarizer.

If exactly one polarizer is present, its absorption direction is preferably perpendicular to the alignment axis of the compounds of the liquid-crystalline medium of the device according to the invention on the side of the switching layer where the polarizer is located.

In the device according to the invention, both absorptive and reflective polarizers may optionally be employed. Preferably, a polarizer in the form of a thin optical film is used. Examples of reflective polarizers that can be used in the device according to the present invention are DRPF (diffuse reflective polarizer film, 3M), DBEF (dual brightness enhanced film, 3M), DBR (Bragg) reflectors of layered polymer distribution, as described in US 7,038,745 and US 6,099,758, and APF films (advanced polarizer film, 3M, see TECHNICAL DIGEST SID 2006, 45.1, US 2011/0043732 and US 7,023,602). Furthermore, polarizers based on wire grids that reflect infrared light (WGP, wire grid polarizers) can be used. Examples of absorptive polarizers optionally useful in the device according to the present invention are Itos XP polarizer film and Nitto Denko GU-1220DUN polarizer film. One example of a circular polarizer that may be used in accordance with the present invention is APNCP-035-STD polarizer (American Polarizers). Another example is a CP42 polarizer (ITOS).

In a preferred embodiment, the device according to the invention is an integral part of a window, more preferably a window assembly comprising at least one glass surface, particularly preferably an assembly of insulating glass units.

By window is here preferably meant a structure, in particular in a building, comprising a frame and at least one glass pane surrounding the frame. It preferably comprises an insulating frame and two or more glass panes, i.e. multipane insulating glass.

According to a preferred embodiment, the device according to the invention is applied directly to the glass surface of a window, particularly preferably in the gap between two glass panes of a multipane insulating glass.

The invention furthermore relates to a window comprising a device according to the invention, preferably with the preferred features indicated above.

Due to the electronic nature of the compounds according to the invention, these compounds are suitable for use as organic semiconductors in addition to dyes.

The invention therefore also relates to the use of the compounds of the formula I in organic electronic components such as, for example, organic light-emitting diodes (OLED), organic Field Effect Transistors (OFET), printed circuits, radio frequency identification elements (RFID), lighting elements, photovoltaic devices and optical sensors.

The compounds according to the invention are extremely suitable as dyes due to their coloured nature and good solubility in organic materials.

The invention therefore likewise relates to the use of the dyes of the formula I for coloring polymers.

In the present invention and in particular in the examples below, the structure of the mesogenic compounds is indicated by means of abbreviations (also referred to as acronyms). In such acronyms, the following abbreviations are used for the chemical formulas below in tables a to C. All radicals C _nH_2n+1、C_mH_2m+1 and C _lH_2l+1 or C _nH_2n-1、C_mH_2m-1 and C _lH_2l-1 denote straight-chain alkyl or alkenyl radicals, preferably 1E-alkenyl radicals, each having n, m and l C atoms, respectively. Table a lists the codes for the ring elements of the core structure of the compounds, while table B shows the linkers. Table C gives the meaning of the codes for the left-hand or right-hand end groups. The acronym consists of a code for a ring element with an optional linker followed by a first hyphen and a code for the left-hand end group and a second hyphen and a code for the right-hand end group. Table D shows the illustrative structures of the compounds along with their corresponding abbreviations.

TABLE A Ring elements

TABLE B linker

TABLE C end groups

Where n and m each represent an integer, and three points ".," is a placeholder for other abbreviations from this table.

The following table shows the illustrative structures along with their corresponding abbreviations. These are shown here to illustrate the meaning of the rules for this abbreviation. It also denotes the compounds which are preferably used.

Table D, illustrative Structure

Wherein n, m and l preferably independently of one another represent 1 to 7.

Table E below shows illustrative compounds that may optionally be used as stabilizers in the mesogenic media according to the invention.

Table E

Table E shows possible stabilizers which can be added to the LC medium according to the invention, where n represents an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8.

The LC medium preferably contains 0 to 10% by weight, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight, of stabilizers.

Table F below shows illustrative compounds that may be preferred for use as chiral dopants in mesogenic media according to the invention.

Table F

In a preferred embodiment of the invention, the mesogenic media comprises one or more compounds selected from the group of compounds from table F.

The mesogenic media according to the invention preferably comprise two or more, preferably four or more compounds selected from the group of compounds from tables D, E and F above.

The liquid-crystalline medium according to the invention preferably comprises seven or more, preferably eight or more, individual compounds from the group of compounds from table D, preferably three or more, particularly preferably four or more, compounds having different formulae from the formulae shown in table D.

LC media according to the invention may also comprise compounds in which for example H, C, N, O, cl or F have been replaced by the corresponding isotopes.

All percentage data and quantitative ratios given herein are weight percentages unless explicitly indicated otherwise.

All physical properties were determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals",Status Nov. 1997, Merck KGaA, Germany, unless explicitly indicated otherwise, and were applicable to temperatures of 20 ℃. Unless indicated otherwise, the values of Δn were in each case determined at 589 nm and the values of Δε were determined at 1 kHz. n _e and n _o are in each case the refractive indices of the extraordinary and ordinary beams under the conditions indicated above.

The degree of anisotropy R is determined from the value E (p) of the extinction coefficient (extinction coefficient of the mixture in the case of molecules aligned parallel to the polarization direction of the light) and the value E(s) of the extinction coefficient of the mixture in the case of molecules aligned perpendicular to the polarization direction of the light, in each case at the maximum wavelength of the absorption band of the dye of interest. If the dye has multiple absorption bands, the strongest absorption band is typically selected. As is known in the art, the alignment of the molecules of the mixture is achieved by an alignment layer. To eliminate the effect of the liquid-crystalline medium, other absorption or reflection, each measurement is performed on the same mixture without dye and the value obtained is subtracted.

The measurement is carried out using linearly polarized light whose vibration direction is parallel to the alignment direction (measurement of E (p)) or perpendicular to the alignment direction (measurement of E (s)). This may be achieved by a linear polarizer which is rotated relative to the device to achieve two different polarization directions. The measurement of E (p) and E(s) is thus performed via rotation of the polarization direction of the incident polarized light.

The degree of anisotropy R is calculated from the synthesized value of E(s) and E (p) according to the following formula:

As indicated herein, particularly in "Polarized Light in Optics and Spectroscopy", d.s. Kliger et al ACADEMIC PRESS, 1990. A detailed description of methods for determining the degree of anisotropy of Liquid-crystalline media containing dichroic dyes is also found in B. Bahadur, liquid Crystals-Applications and Uses, volume 3, 1992, world Scientific Publishing, section 11.4.2.

The isotropic extinction coefficient E _iso is calculated from the combined values of E(s) and E (p) according to the following formula:

。

The isotropic extinction coefficient, herein denoted by ε _iso, is calculated according to the following formula:

,

wherein c is the dye concentration, in particular given in weight%, and d is the measured layer thickness of the guest-host medium, in particular given in cm.

The following examples merely illustrate the invention and are not to be construed as limiting the scope of the invention in any way. This example, and modifications and other equivalents thereof, will become apparent to those skilled in the art in light of this disclosure.

Detailed Description

Examples

In the case of an embodiment of the present invention,

V _o denotes the threshold voltage at 20 ℃, the capacitance V,

N _e represents the extraordinary refractive index at 20 ℃ and 589 nm,

N _o represents the ordinary refractive index at 20 ℃ and 589 nm,

An represents optical anisotropy at 20 ℃ and 589 nm,

Epsilon _∥ represents the dielectric constant parallel to the director at 20C and 1 kHz,

Epsilon _⊥ represents the dielectric constant perpendicular to the director at 20C and 1 kHz,

Delta epsilon represents the dielectric anisotropy at 20 ℃ and 1 kHz,

Cl.p., T (N, I) represents a clearing point [ ° C ],

Gamma ₁ denotes the rotational viscosity [ mpa.s ] measured at 20C, measured by the rotational method in a magnetic field,

K ₁ denotes the elastic constant, the "splay" deformation [ pN ] at 20 ℃,

K ₂ denotes the elastic constant, the "twist" deformation [ pN ] at 20 ℃,

K ₃ denotes the elastic constant, the "bending" deformation [ pN ] at 20 ℃,

The term "threshold voltage" of the present invention relates to a capacitance threshold (V ₀) unless explicitly indicated otherwise. In an embodiment, as usual, an optical threshold of 10% relative contrast (V ₁₀) may also be indicated.

Synthetic examples

Synthesis example 1

Preparation of Compound 1

Step 1:

4, 5-bis (2-ethylhexyl) -dithieno [2,3-d:2',3' -d '] thieno [3,2-b:4,5-b' ] bipyrrolidinyl is obtainable according to Chung, chin-Lung et al, organic Electronics 2018, 18, 6-16. Aluminum chloride (0.48 g,3.60 mmol) was added to a stirred solution of 4, 5-bis (2-ethylhexyl) -dithioeno [2,3-d:2',3' -d '] thieno [3,2-b:4,5-b' ] dipyrrolidinyl (0.60 g,1.20 mmol) and heptanoyl chloride (0.36 g,2.40 mmol) in dichloromethane (6 mL) at room temperature. After stirring 18 h at this temperature, the resulting red solution was carefully added to a cooled HCl solution (2N) and extracted with dichloromethane. The combined organic phases were dried over sodium sulfate. Final purification by column chromatography (silica; heptane/DCM: 9/1) gave the ketone product as a red oil. EI-MS: m/z, 610.3.

Step 2:

A solution of N-bromosuccinimide (0.28 g,1.57 mmol) in THF (10 mL) was added dropwise to a stirred solution of the ketone obtained in step 1 (1.00 g,1.64 mmol) in THF (10 mL) at 0℃in the absence of light. The resulting solution was allowed to warm to room temperature and stirred at this temperature for a further 2h a. Purification was performed by column chromatography (silica; heptane/DCM: 9/1) to give the bromo-ketone product as a red solid. This compound was used directly in the next step without further purification.

Step 3:

N, N-dihexyl-4- (4, 5-tetramethyl-1, 3, 2-dioxaborolan-2-yl) aniline is obtainable from Chung, bures et al, sci. Pap. Univ. Pardubice, ser. A2014, 20, 247-259. Pd (OAc) ₂ (18.4 mg,0.08 mmol), sphos (69,4 mg,0.16 mmol), the bromo-ketone product obtained in step 2 (1.13 g,1.64 mmol), K ₃PO₄ (1.05 g,4.94 mmol) and N, N, -dihexyl-4- (4, 5-tetramethyl-1, 3, 2-dioxaborolan-2-yl) aniline (1.03 g,2.46 mmol) were dissolved in THF (10 mL) and water (2 mL). The resulting mixture was heated to 65 ℃ and stirred at this temperature for 18 h a. The reaction mixture was extracted with dichloromethane. The combined organic phases were dried over MgSO ₄ and filtered off. Final purification by column chromatography (reverse phase; acetonitrile/THF) yielded compound 1 as a red oil.

¹ H-NMR (pyridine -d₅, 700 MHz): δ = 8.35 (s, 1H), 7.82 (d, J = 8.0 Hz, 2H), 7.71 (s, 1H), 6.85 (d, J = 8.0 Hz, 2H), 4.59 - 4.46 (m, 4H), 3.32 - 3.29 (m, 4H), 3.03 - 3.01 (m, 2H), 2.25 - 2.20 (m, 2H), 1.84 - 1.80 (m, 2H), 1.60 - 1.57 (m, 4H), 1.34 - 1.25 (m, 24H), 1.19 - 1.10 (m, 10H), 0.87 - 0.75 (m, 21H).)

APCI-MS: m/z: 870.5。

Compound 1 shows the absorption maximum at isotropic extinction coefficient epsilon _iso of lambda _max = 470 nm and 750 (wt% cm) ^-1, measured in host mixture H-1 as given below.

Synthesis example 2

Preparation of Compound 2

Step 1:

Aluminum chloride (1.60 g,12.03 mmol) was added to a stirred solution of 4, 5-bis (2-ethylhexyl) -dithieno [2,3-d:2',3' -d '] thieno [3,2-b:4,5-b' ] dipyrrole (1.00 g,2.00 mmol) and 2-ethylhexanoyl chloride (1.30 g,7.99 mmol) in dichloromethane (10 mL) at room temperature. After stirring 18 h at this temperature, the resulting red solution was carefully added to a cooled HCl solution (6N) and extracted with dichloromethane. The combined organic phases were dried over sodium sulfate. Final purification by column chromatography (silica; DCM) and recrystallization from DCM/MeOH: 2/5 gave the ketone product as a red oil. APCI-MS: m/z 625.3.

Step 2:

A solution of N-bromosuccinimide (0.19 g,1.12 mmol) in THF (3 mL) was added dropwise to a stirred solution of the ketone product obtained in step 1 (0.70 g,0.64 mmol) in THF (3 mL) at 0℃under dark conditions. The resulting solution was allowed to warm to room temperature and stirred at this temperature for an additional 2h. Purification was performed by column chromatography (silica; DCM) to give the bromo-ketone product as a red solid. This compound was used directly in the next step without further purification.

Step 3:

pd (OAc) ₂ (11.5 mg,0.05 mmol), SPhos (43.4 mg,0.10 mmol), the bromo-ketone product obtained in step 2 (0.85 g,1.21 mmol,HPLC:85%), K ₃PO₄ (0.65 g,3.09 mmol) and N, N, -dihexyl-4- (4, 5-tetramethyl-1, 3, 2-dioxaborolan-2-yl) aniline (0.60 g,1.55 mmol) were dissolved in THF (7 mL) and water (2 mL). The resulting mixture was heated to 65 ℃ and stirred at this temperature for 3 d a. The reaction mixture was extracted with dichloromethane. The combined organic phases were dried over MgSO ₄ and filtered off. Final purification by column chromatography (reverse phase; acetonitrile/THF) yielded compound 2 as a red oil.

¹H-NMR (CDCl₃, 700 MHz): δ = 7.64 (s, 1H), 7.48 (d, J = 8.4 Hz, 2H), 7.02 (s, 1H), 6.65 (d, J = 8.5 Hz, 2H), 4.33 - 4.21 (m, 4H), 3.31 - 3.27 (m, 4H), 3.11 - 3.09 (m, 1H), 2.04 - 1.97 (m, 2H), 1.86 - 1.80 (m, 2H), 1.63 - 1.52 (m, 7H), 1.36 - 1.29 (m, 13H), 1.28 - 1.12 ( m, 18 H), 0.94 - 0.78 (m, 24H).

APCI-MS: m/z: 884.5。

Compound 2 shows the absorption maximum at isotropic extinction coefficient epsilon _iso of lambda _max = 470 nm and 715 (wt% cm) ^-1 as determined in host mixture H-1 given below.

Synthesis example 3

Preparation of Compound 3

Compound 1 (100 mg,0.11 mmol), malononitrile (2.28 g,34.45 mmol) and lithium bis (trimethyl) amide (lithium-bis (trimethyl) azanide) (0.96 g,5.58 mmol) prepared as in Synthesis example 1 were dissolved in 1, 2-dichloroethane (3 mL) and stirred at 80℃for 18 h. Water (100 mL) and DCM (100 mL) were added to the cooled reaction mixture. The phases were separated and the organic phase was washed several times with water. The solvent was removed and the resulting solid was dissolved in DCM and precipitated by addition of MeOH. Final purification by column chromatography (silica; heptane/toluene: 1/1) yielded compound 3 as a blue solid.

¹H-NMR (CDCl₃, 700 MHz): δ = 8.16 (s, 1H), 7.49 (d, J = 8.7 Hz, 2H), 7.01 (s, 1H), 6.65 (d, J = 8.7 Hz, 2H), 4.33 - 4.21 (m, 4H), 3.32 - 3.29 (m, 4H), 2.94 -2.90 (m, 2H), 2.02 - 1.97 (m, 2H), 1.81 - 1.75 (m, 2H), 1.64 - 1.61 (m, 4H), 1.51 - 1.48 (m, 2H), 1.37 - 1.32 (m, 16H), 1.28 - 1.15 ( m, 16H), 0.93 - 0.89 (m, 9H), 0.87 - 0.78 (m, 12H).

APCI-MS: m/z: 918.5。

Compound 3 shows an absorption maximum at isotropic extinction coefficients epsilon _iso of lambda _max = 602 nm and 880 (wt% cm) ^-1 as determined in the host mixture H-1 given below.

Synthesis example 4

Preparation of Compound 4

Step 1:

N-BuLi (1.38 mL,2.21 mmol,1.6M in hexane) was added dropwise to a stirred solution of 4, 5-bis (2-ethylhexyl) -dithioeno [2,3-d:2',3' -d '] thieno [3,2-b:4,5-b' ] dipyrrolidinyl (1.09 g,2.18 mmol) in THF (15 mL) at-78 ℃. After stirring 1 h at this temperature, the resulting red solution was warmed to room temperature and CO ₂ gas was bubbled through the solution for 1 h. HCl (2M) and ethyl acetate were added. The organic phase was separated and dried over sodium sulfate. Final purification by recrystallisation from n-heptane yielded the carboxylic acid product as a red solid.

¹H-NMR (CDCl₃, 400 MHz): δ = 7.80 (s, 2H), 7.16 (d, J = 5.2 Hz, 1H), 7.00 (d, J = 5.2 Hz, 1H), 4.47 - 4.10 (m, 4H), 2.00 (m, 2H), 1.28 - 1.19 (m, 16H), 0.84 - 0.77 (m, 12H).

EI-MS: m/z: 542.4。

Step 2:

A solution of ({ [3- (dimethylamino) propyl ] imino } methylene) (ethyl) amine (0.38 g,2.45 mmol) in toluene (1 mL) was added dropwise to the carboxylic acid product (1.10 g,2.02 mmol) obtained in step 1 in toluene (5.5 mL) at 0 ℃. The resulting solution was allowed to warm to room temperature and stirred at this temperature for 16 h more. Oxalic acid (53 mg,0.40 mmol) was added and stirred for 1 h. Purification was performed by column chromatography (silica; toluene) to give the carboxylate product as a red oil. This compound was used directly in the next step without further purification.

Step 3:

A solution of N-bromosuccinimide (275 mg,1.54 mmol) in THF (21 mL) was added to the carboxylate product (1.00 g,1.47 mmol) obtained in step 2 in THF (72 mL) at 0℃under dark conditions. The solution was stirred at this temperature for another 30min a and then the mixture was allowed to warm to room temperature overnight. Purification by column chromatography (silica; THF) gave the bromo-carboxylate product (APCI-MS: m/z: 758.1) as a red solid. This compound was used directly in the next step without further purification.

Step 4:

A solution of N, N-dihexyl-4- (4, 5-tetramethyl-1, 3, 2-dioxaborolan-2-yl) aniline (0.68 g,1.65 mmol) in toluene (6 mL) was slowly added to a mixture of Pd ₂dba₃(5.1 mg,0.01 mmol)、P(o-tol)₃ (6.8 mg,0.02 mmol) and the bromo-carboxylate product (0.53 g,0.56 mmol,HPLC:80%) obtained in step 3 in toluene (11 ml) and aqueous Na ₂CO₃ (2.2 mL, 2M). The resulting mixture was stirred at 100 ℃ for 18 h, then a mixture of Pd ₂dba₃(3.6 mg,0.01 mmol)、P(o-tol)₃ (6.6 mg,0.02 mmol), toluene (3 ml) and aqueous Na ₂CO₃ (1.2 ml,2 m) was added and the resulting mixture was stirred at 100 ℃ for 18 h more. Water (30 mL) and MTBE (30 mL) were added to the cooled reaction mixture. The phases were separated and the aqueous phase was extracted several times with MTBE. The combined organic phases were dried over sodium sulfate and filtered off. Final purification by column chromatography (reverse phase; acetonitrile/THF) and recrystallization from heptane/toluene:2/1 yielded compound 4 as an orange solid.

¹H-NMR (CDCl₃, 500 MHz): δ = 7.84 (s, 1H), 7.48 - 4.46 (m, 2H), 7.13 - 7.11 (m, 2H), 7.02 (s, 1H), 6.67 - 6.65 (m, 2H), 4.36 - 4.21 (m, 4H), 3.31 - 3.27 (m, 4H), 2.02 - 2.00 (m, 2H), 2.04 - 1.97 (m, 2H), 1.62 - 1.60 (m, 4H), 1.34 - 1.18 (m, 28H), 0.93 - 0.90 ( m, 6H), 0.84 - 0.80 (m, 12H).

APCI-MS: m/z: 939.5。

Compound 4 shows an absorption maximum at isotropic extinction coefficient epsilon _iso of lambda _max = 485 nm and 695 (wt% cm) ^-1 as determined in the host mixture H-1 given below. The degree of anisotropy R, as determined in the host mixture H-1 given below, was 0.70.

Synthetic examples 5, 6, 7, 8 and 9

In analogy to the above synthesis examples 1 to 4, the following compounds 5, 6, 7, 8 and 9 were prepared and their physical properties were characterized.

Compound 5

Compound 5 shows the absorption maximum at isotropic extinction coefficients epsilon _iso of lambda _max = 721 nm and 840 (wt% cm) ^-1 as determined in the host mixture H-1 given below.

Compound 6

Compound 6 shows the absorption maximum at isotropic extinction coefficients epsilon _iso of lambda _max = 473 nm and 675 (wt% cm) ^-1 as determined in the host mixture H-1 given below. The degree of anisotropy R, as determined in the host mixture H-1 given below, was 0.71.

Compound 7

Compound 7 shows the absorption maximum at isotropic extinction coefficient epsilon _iso of lambda _max = 598 nm and 685 (wt% cm) ^-1 as determined in the host mixture H-1 given below.

Compound 8

Compound 9

Mixture examples and comparative mixture examples

Comparative mixture example 1

Liquid crystal host mixture H-1 was prepared and characterized for its general physical properties, having the composition and properties indicated in the following table.

Comparative mixture CM-1 was prepared by mixing 96.621% of mixture H-1 and 0.100% of a compound of the formula,

(Which will be referred to hereinafter as ST-1), 0.100% of a compound of the formula:

(which will be hereinafter referred to as ST-2), 0.127% of a compound of the formula R-5011 as described in Table F above, 0.476% of a compound of the formula,

(Which will be referred to hereinafter as D-A1), 1.246% of a compound of the formula:

(which will be referred to hereinafter as D-A2) and 1.330% of a compound of the formula:

(which will be referred to as D-A3 hereinafter).

Comparative mixture example 2

Liquid crystal host mixture H-2 was prepared and characterized for its general physical properties, having the composition and properties indicated in the following table.

Comparative mixture CM-2 was prepared by mixing 90.68% of mixture H-2 and 0.10% of compound ST-1, 1.05% of a compound of the formula,

(Which will be referred to hereinafter as D-B1), 1.63% of a compound of the formula:

(which will be referred to hereinafter as D-B2), 2.10% of a compound of the formula:

(which will be referred to hereinafter as D-B3), 1.64% of a compound of the formula:

(which will be referred to hereinafter as D-B4), 0.60% of a compound of the formula:

(which will be referred to hereinafter as D-B5) and 2.20% of a compound of the formula:

(which will be referred to as D-B6 hereinafter).

Comparative mixture CM-2.1 was prepared by mixing 99.847% of mixture CM-2 and 0.153% of the compound of formula R-5011 as described in Table F above.

Comparative mixture CM-2.2 was prepared by mixing 99.673% of mixture CM-2 and 0.327% of the compound of formula R-5011 as described in table F above.

Comparative mixture example 3

Comparative mixture CM-3 was prepared by mixing 94.22% of mixture H-2 and 0.10% of compound ST-1, 0.10% of compound ST-2, 0.83% of compound D-A1, 1.00% of compound D-A2, 1.57% of compound D-A3 and 2.18% of compound of formula S-811 as described in Table F above.

Comparative mixture example 4

Liquid crystal host mixture H-3 was prepared and characterized for its general physical properties, having the composition and properties indicated in the following table.

Liquid crystal reference mixture H-3.1 was prepared by mixing 99.97% of mixture H-3 and 0.03% of compound ST-1.

Comparative mixture CM-4 was prepared by mixing 90.128% of mixture H-3.1 and 1.160% of compound D-B1, 1.919% of compound D-B2, 1.800% of compound D-B3, 1.300% of compound D-B4, 0.730% of compound D-B5, 2.110% of compound D-B6 and 0.853% of compound of the formula:

Comparative mixture CM-4.1 was prepared by mixing 99.236% of mixture CM-4 and 0.764% of the compound of formula S-811 as described in Table F above.

Comparative mixture CM-4.2 was prepared by mixing 98.980% of mixture CM-4 and 1.020% of compound of formula S-811 as described in Table F above.

Examples of mixtures

The dyes prepared in synthesis examples 1 to 7 were investigated for their applicability in LC media and devices for regulating energy transfer.

Mixture example 1

Mixture M-1 was prepared by adding 0.030% compound ST-1, 0.050% compound of formula S-811, 0.213% compound 1, 0.233% compound 3 and 0.120% compound 4 as described in Table F above to the host mixture H-1 as indicated above.

The mixture M-1 was filled into TN double cells each having a cell thickness of 25 μm and a polyimide alignment layer having a pretilt angle of 1 °. Although only a relatively small amount of dichroic dye is used, the electro-optic cell exhibits a favorable contrast between the dark and bright states.

Mixture example 2

Mixture M-2 was prepared by adding 0.030% compound ST-1, 0.050% compound of formula S-811, 1.122% compound 2, 0.600% compound 4 and 1.500% compound 7 as described in Table F above to the host mixture H-2 as shown above.

The mixture M-2 was filled into TN double cells each having a cell thickness of 5 μm and a polyimide alignment layer having a pretilt angle of 1 °. Although the cartridge has only a relatively small thickness, the device exhibits a favorable contrast between the dark and light states.

Mixture example 3

Mixture M-3 was prepared by adding 0.030% compound ST-1, 0.420% compound 3, 0.097% compound 4, 0.081% compound 5 and 0.432% compound 6 to the host mixture H-3 as shown above.

The mixture M-3 was filled into VA double cells, wherein the cells each had a cross geometry and a cell thickness of 15 μm and polyimide alignment layer with a pretilt angle of 89. The electro-optical device exhibits an advantageous contrast between the dark state and the bright state.

Mixture example 4

Mixture M-4 was prepared by adding 0.030% compound ST-1, 1.010% compound of formula S-811, 1.070% compound 1, 1.165% compound 3, 0.299% compound 4 and 0.250% compound 5 as described in Table F above to the host mixture H-3 as shown above.

The mixture M-4 was filled into a VA single cell, wherein the cell had a twist of 240℃and a thickness of 8 μm and a polyimide alignment layer with a pretilt angle of 85 ℃. Although the cell is only a single cell with a relatively small thickness of the switching layer, the device exhibits a favorable contrast between the dark and light states.

Mixture example 5

Mixture M-5 was prepared by adding 0.03% compound ST-1, 2.50% compound 1, 2.10% compound 3, 0.57% compound 4 and 0.48% compound 5 to the host mixture H-3 as indicated above.

The mixture M-5 was filled into a VA single cell, wherein the cell was twist-free and had a thickness of 6 μm and a polyimide alignment layer with a pretilt angle of 89. Although the cell is only a single cell with a relatively small thickness of the switching layer, the device exhibits a suitable contrast between the dark and light states.

Mixture example 6

Mixture M-6 was prepared by adding 0.03% compound ST-1, 1.34% compound of formula S-811, 2.50% compound 1, 2.10% compound 3, 0.57% compound 4 and 0.48% compound 5 as described in Table F above to the host mixture H-3 as shown above.

The mixture M-6 was filled into a VA single cell, wherein the cell had a twist of 240℃and a thickness of 6 μm and a polyimide alignment layer with a pretilt angle of 85 ℃. Although the cell is only a single cell with a relatively small thickness of the switching layer, the device exhibits a favorable contrast between the dark and light states.

Mixture example 7

Mixture M-7 was prepared by adding 0.76% of the compound of formula S-811, 2.05% of compound 1, 1.80% of compound 3 and 1.02% of compound 4 as described in table F above to the host mixture H-1 as indicated above.

The mixture M-7 was filled into an STN cassette having a twist of 240℃and a polyimide alignment layer having a thickness of 6 μm and a pretilt angle of 5 ℃. Although the cell is only a single cell with a relatively small thickness of the switching layer, the device exhibits a favorable contrast between the dark and light states.

Mixture example 8

Mixture M-8 was prepared by adding 0.38% of the compound of formula R-5011, 2.05% of compound 1, 1.80% of compound 3 and 1.02% of compound 4 as described in table F above to the host mixture H-1 as shown above.

The mixture M-8 was filled into a planar highly twisted HTN cell, wherein the cell had a 1080 ° twist and a 6 μm thickness and a polyimide alignment layer with a pretilt angle of 1 °. Although the cell is only a single cell with a relatively small thickness of the switching layer, the device exhibits a favorable contrast between the dark and light states.

Mixture example 9

Mixture M-9 was prepared by adding 0.10% compound ST-1, 0.10% compound ST-2, 0.23% compound of formula R-5011, 0.90% compound 2, 0.31% compound 4, 0.27% compound 5, 0.95% compound 6 and 2.50% compound 7 as described in table F above to the host mixture H-1 as shown above.

The mixture M-9 was filled into a planar highly twisted HTN cell, wherein the cell had a 1080 ° twist and a 10 μm thickness and a polyimide alignment layer with a pretilt angle of 1 °. The device exhibits a favorable contrast between the dark state and the bright state.

Mixture example 10

Mixture M-10 was prepared by adding 0.10% compound ST-1, 0.90% compound 1, 1.35% compound 3 and 1.04% compound 4 to the host mixture H-2 as indicated above.

The mixture M-10 was filled into a Heilmier cell equipped with a linear polarizer, wherein the cell had a thickness of 5 μm and a polyimide alignment layer with a pretilt angle of 1 °. The device exhibits a suitable contrast between the dark state and the bright state.

The compounds 1 to 9 and the mixtures M-1 to M-10 are very suitable for regulating the passage of energy through an external space into an internal space, for example into a device for windows.

Claims (17)

1. Compounds of formula I

Wherein the method comprises the steps of

R ¹ and R ² are identical or different and represent H, F, CN, N (R ^z)₂, straight-chain alkyl having 1 to 20C atoms or branched or cyclic alkyl having 3 to 20C atoms, where, in addition, one or more non-adjacent CH ₂ groups can each, independently of one another, be replaced by-C (R ^z)=C(R^z) -, -C≡C-,、、、、-N (R ^z) -, -O-, -S-, -CO-O-, -O-CO-, or-O-CO-O-is replaced in such a manner that O and/or S atoms are not directly connected to each other, and wherein, in addition, one or more H atoms can be replaced by F, cl, br, I or CN,

R ^z represents, identically or differently for each occurrence, H, halogen, straight-chain alkyl having 1 to 12C atoms or branched or cyclic alkyl having 3 to 12C atoms, where, in addition, one or more non-adjacent CH ₂ groups may be replaced by-O-, -S-, -CO-O-, O-CO-or-O-CO-O-is replaced in such a way that the O and/or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may be replaced by F or Cl,

Q ¹ and Q ², which are identical or different, represent a single bond 、-O-、-S-、-CF₂O-、-OCF₂-、-CF₂-、-CF₂CF₂-、-CO-、-CR^x1=CR^x2-、-C≡C-、-NR^x1-、-N=N- or a cycloaliphatic or heterocyclic group, preferably having from 4 to 25 ring atoms, which may also comprise condensed rings, and which are unsubstituted or mono-or polysubstituted by L,

Z ¹ and Z ², which are identical or different, represent a single bond 、-O-、-S-、-C(O)-、-CR^y1R^y2-、-CF₂O-、-OCF₂-、-C(O)-O-、-O-C(O)-、-O-C(O)-O-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂S-、-SCF₂-、-(CH₂)_n1-、-CF₂CH₂-、-CH₂CF₂-、-(CF₂)_n1-、-CR^x1=CR^x2-、-C≡C-、-CR^x1=CR^x2-CO-、-CO-CR^x1=CR^x2-、-CR^x1=CR^x2-COO-、-OCO-CR^x1=CR^x2- or-N=N-,

R ^x1、R^x2 independently of one another represents H, F, cl, CN or alkyl having 1 to 12C atoms,

R ^y1 represents H or an alkyl group having 1 to 12C atoms,

R ^y2 represents an alkyl group having 1 to 12C atoms,

N1 represents 1, 2, 3 or 4,

A ¹ and A ², which are identical or different, represent aromatic, heteroaromatic, cycloaliphatic or heterocyclic radicals, preferably having from 4 to 25 ring atoms, which may also comprise condensed rings, and which are unsubstituted or monosubstituted or polysubstituted by L,

L represents F, cl, -CN or a linear alkyl having 1 to 25C atoms or a branched or cyclic alkyl having 3 to 25C atoms, wherein one or more non-adjacent CH ₂ -groups are optionally replaced by-O-, -S-, -CO-O-, O-CO-or-O-CO-O-is replaced in such a way that O atoms and/or S atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by F or Cl,

D represents a donor group selected from heteroaromatic groups comprising at least 4 fused rings, wherein each ring may be unsubstituted or mono-or polysubstituted by L,

A represents a group of an acceptor and,

N represents 0,1, 2 or 3, and

O represents either 0 or 1 and,

Wherein the number of rings in the compound is at least 5.

2. A compound according to claim 1, wherein the acceptor group a is an electron withdrawing group, preferably an electron-deficient moiety lacking pi electrons.

3. The compound of claim 1 or 2, wherein the donor group D is a heteroacene having linear fused rings, wherein each ring may be unsubstituted or mono-or polysubstituted by L, wherein L is defined as in claim 1.

4. A compound according to one or more of claims 1 to 3, wherein:

A ¹ represents, identically or differently on each occurrence, aryl or heteroaryl, which may be substituted by one or more radicals L as defined in claim 1, preferably 1, 4-phenylene, 1, 4-naphthylene, 2, 6-naphthylene, thiazole-2, 5-diyl, thiophene-2, 5-diyl, thienothiophene-2, 5-diyl, selenophene-2, 5-diyl, thienopyrrole-2, 5-diyl, dithienopyrroldiyl, dithienosyclopentadienyl, cyclopentadithiophenediyl, pyridine-2, 5-diyl, pyrimidindiyl or pyridazindiyl, wherein one or more H atoms may be replaced by a radical L as defined in claim 1, and/or

Q ¹ and Z ¹ represent a single bond, and/or

N represents 1 or 2, preferably 1, and/or

O represents 0.

5. A compound according to one or more of claims 1 to 4, wherein the compound has an isotropic extinction coefficient of at least 500 (wt% cm) ^-1.

6. A mixture comprising two or more compounds according to one or more of claims 1 to 5.

7. Use of a compound according to one or more of claims 1 to 5 in a liquid-crystalline medium.

8. Liquid-crystalline medium comprising one or more compounds according to one or more of claims 1 to 5 and additionally comprising at least one mesogenic compound.

9. The liquid-crystalline medium according to claim 8, wherein the medium comprises one or more compounds selected from the group of compounds of formulae II-1 and II-2:

Wherein the method comprises the steps of

R ² represents alkyl, alkoxy, fluoroalkyl or fluoroalkoxy having 1 to 7C atoms, or alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2 to 7C atoms,

Wherein optionally one or more CH ₂ groups may be used independently of one another、、、Or (b)Instead of this, the first and second heat exchangers,

AndIndependently of one another are

Or (b),

L ²¹、L²²、L²³ and L ²⁴ independently of one another represent H or F,

L ²⁵ represents H or CH ₃, and

X ² represents halogen, halogenated alkyl or alkoxy having 1 to 3C atoms or halogenated alkenyl or alkenyloxy having 2 or 3C atoms.

10. The liquid-crystalline medium according to claim 8 or 9, wherein the medium comprises one or more compounds selected from the group of compounds of formulae III and IV:

Wherein the method comprises the steps of

R ³、R⁴、R⁵ and R ⁶ independently of one another represent a group selected from: F, CF ₃、OCF₃, CN and straight-chain or branched alkyl or alkoxy having from 1 to 15 carbon atoms or straight-chain or branched alkenyl having from 2 to 15 carbon atoms, which are unsubstituted, monosubstituted by CN or CF ₃ or monosubstituted or polysubstituted by halogen, and wherein one or more CH ₂ groups may be replaced in each case independently of one another by-O-, -S-, -CO-, -COO-, -OCO-, -OCOO-or-C.ident.C-in such a way that the oxygen atoms are not directly connected to one another, and

L ¹、L²、L³、L⁴ and L ⁵ independently of one another represent H or F.

11. The liquid-crystalline medium according to one or more of claims 8 to 10, wherein the medium comprises one or more compounds selected from the group of compounds of formulae CY, PY and AC:

Wherein the method comprises the steps of

A represents 0,1 or 2, preferably 1 or 2,

B represents 0 or 1, and the number of the groups is,

C represents 0,1 or 2,

D represents either 0 or 1 and is preferably used,

Representation ofOr (b),

And

Representation of

Or (b),

Representation of

Or (b),

R ¹、R²、R^AC1 and R ^AC2 each independently of one another represent alkyl having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ groups can be reacted、、、、-O-, -CH=CH-, -CO-, -OCO-, or-COO-is replaced in such a way that the O atoms are not directly connected to each other, preferably alkyl or alkoxy having 1 to 6C atoms,

Z ^x、Z^y and Z ^AC each independently of one another represent -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, and

L ^1-4 each independently of the other represents F, cl, CN, OCF ₃、CF₃、CH₃、CH₂ F or CHF ₂, preferably F.

12. Liquid-crystalline medium according to one or more of claims 8 to 11, wherein the medium further comprises one or more dichroic dyes, which are different from the compounds of formula I as described in claims 1 to 5.

13. The liquid-crystalline medium according to one or more of claims 8 to 12, wherein the medium further comprises

-One or more chiral compounds, preferably of the formula

,

More preferably the R stereoisomer of the chiral compound, and/or

-One or more stabilizers, and/or

One or more polymerizable compounds, preferably one or more polymerizable mesogenic compounds.

14. Use of a compound according to one or more of claims 1 to 5 or of a liquid-crystalline medium according to one or more of claims 8 to 13 in an electro-optical display, a device for regulating the passage of energy through an external space into an internal space, an electronic semiconductor, an organic field effect transistor, a printed circuit, a radio frequency identification element, an organic light-emitting diode, a lighting element, a photovoltaic device, an optical sensor, an effect pigment, a decorative element or as a dye for coloring a polymer.

15. Device for regulating the passage of energy through an external space into an internal space, wherein the device contains a switching layer comprising a liquid-crystalline medium according to one or more of claims 8 to 13.

16. A window comprising the device of claim 15.

17. A process for preparing a compound of formula I according to claim 1, wherein the process comprises

-Providing a compound of formula I-Br

Wherein D, A, Z ²、A²、Q²、R² and o have the meanings as defined in claim 1, and

-Subjecting said compound of formula I-Br to a chemical reaction, preferably a cross-coupling reaction.