CN110997870B

CN110997870B - Liquid crystal medium and liquid crystal device

Info

Publication number: CN110997870B
Application number: CN201880050921.5A
Authority: CN
Inventors: S·希米安诺斯基; M·布雷米尔; J·耶恩
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2017-08-08
Filing date: 2018-08-06
Publication date: 2023-08-22
Anticipated expiration: 2038-08-06
Also published as: TW201920619A; WO2019030153A1; CN110997870A

Abstract

The present invention relates to compounds of formula (I), R ¹¹ ‑A ¹¹ ‑(Z ¹¹ ‑A ¹² ) _p ‑X ¹¹ ‑Sp ¹¹ ‑X ¹² ‑(A ¹³ ‑Z ¹³ ) _q ‑A ¹⁴ ‑R ¹² I wherein R is ¹¹ 、R ¹² 、A ¹¹ To A ¹⁴ 、Z ¹¹ 、Z ¹³ 、X ¹¹ 、X ¹² 、Sp ¹¹ P and q have one of the meanings given below. The invention also relates to a process for preparing the compounds of formula I, to the use of the compounds in liquid-crystalline media and to liquid-crystalline media comprising one or more compounds of formula I. Furthermore, the invention relates to a method for producing such a liquid crystal medium, to the use of such a medium in a liquid crystal device, in particular in a curved electrohydraulic device, and to a curved electrohydraulic device comprising a liquid crystal medium according to the invention.

Description

Liquid crystal medium and liquid crystal device

The present invention relates to compounds of the formula I,

R ¹¹ -A ¹¹ -(Z ¹¹ -A ¹² ) _p -X ¹¹ -Sp ¹¹ -X ¹² -(A ¹³ -Z ¹³ ) _q -A ¹⁴ -R ¹² I

wherein R is ¹¹ 、R ¹² 、A ¹¹ To A ¹⁴ 、Z ¹¹ 、Z ¹³ 、X ¹¹ 、X ¹² 、Sp ¹¹ P and q have one of the meanings given below. The invention also relates to a process for preparing the compounds of formula I, to the use of the compounds in liquid-crystalline media and to liquid-crystalline media comprising one or more compounds of formula I. Furthermore, the invention relates to a method for producing such a liquid crystal medium, to the use of such a medium in a liquid crystal device, in particular in a curved electrohydraulic device, and to a curved electrohydraulic device comprising a liquid crystal medium according to the invention.

Background and prior art

The electrobending effect is described, for example, in Chandrasekhar, "Liquid Crystals", 2 nd edition, cambridge University Press (1992) and P.G.degens et al, "The Physics of Liquid Crystals", 2 nd edition, oxford Science Publications (1995).

The ferroelectric devices using the ferroelectric effect and liquid crystal media particularly suitable for ferroelectric devices are known from EP0971016, GB2356629 and Coles, h.j., musgrave, b., coles, m.j., and Willmott, j., j.

The uniform horizontal spiral (ULH) has a high potential as a fast switching liquid crystal display mode. It is capable of sub-millisecond switching at 35 ℃ and has an inherently high aperture ratio, resulting in an energy efficient display mode.

The materials commonly used in media suitable for ULH mode are typically bimesogenic. Because of the size of these materials and the presence of polar groups such as terminal cyano groups, they generally have a high rotational viscosity (γ) on the order of thousands mpa s at 35 ℃ ₁ ). High gamma ₁ The value is not problematic at elevated temperatures, e.g. 35 c, since the switching speed is directly related to gamma ₁ Proportional to the ratio. On the other hand, gamma ₁ The value of (2) is also proportional to the square of the chiral pitch. Since the chiral pitch is typically in the range of 300nm, this means that the switching speed is still very fast, in the region of 1 millisecond or a few milliseconds.

However, when lower temperatures are reached, such as room temperature, γ, at which ULH devices typically operate ₁ The value of (2) increases exponentiallyAdditionally, even for short pitch materials, the switching speed increases beyond a favorable level.

In order to maintain a fast switching speed at temperatures below 35 ℃, it is necessary to reduce the value γ of the liquid crystal mixture ₁ And thus there is a need to identify compounds with lower gamma ₁ Is used as a component of the mixture.

Thus, there is a great need for new bimesogenic compounds which exhibit an advantageously low gamma ₁ Values, while preferably displaying:

advantageous e/K (V ^-1 ) The value of the sum of the values,

advantageous broad nematic phase range and

high definition bright spot.

In addition to these requirements, the corresponding liquid-crystalline media should exhibit advantageously low gamma ₁ Values, while preferably displaying:

a low melting point,

a high-definition bright point,

a broad chiral nematic phase range,

a short temperature independent pitch length,

high bending modulus, and

advantageous low-temperature stability, no crystallization effect in the box and in the form of lumps (in the bulk).

Other objects of the present invention will be apparent to those skilled in the art from the following detailed description.

Surprisingly, the inventors have found that one or more of the above objects can be achieved by providing a compound according to claim 1.

Terminology and definitions

The term "liquid crystal", "mesogenic compound (mesomorphic compound)" or "mesogenic compound" (also simply "mesogenic") means a compound which can exist as an intermediate phase (nematic, smectic, etc.) or in particular as a liquid crystal phase under suitable conditions of temperature, pressure and concentration. The non-amphiphilic mesogenic compound comprises, for example, one or more rod-like, banana-like or disc-like mesogenic groups.

In this context, the term "mesogenic group" means a group having the ability to induce Liquid Crystal (LC) phase behaviour. The compounds containing mesogenic groups do not necessarily have to exhibit a liquid crystal phase per se. They may also exhibit liquid crystal phase behaviour only in mixtures with other compounds. For simplicity, the term "liquid crystal" is used hereinafter for both mesogenic and liquid crystal materials.

Throughout the present application, unless explicitly stated otherwise, the terms "aryl and heteroaryl" encompass groups that may be monocyclic or polycyclic, i.e., they may have one ring (e.g., phenyl) or two or more rings, which may also be fused (e.g., naphthyl) or covalently linked (e.g., biphenyl), or contain a combination of fused and linked rings.

Heteroaryl contains one or more heteroatoms preferably selected from O, N, S and Se. Particularly preferred are monocyclic, bicyclic or tricyclic aryl groups having 6 to 25C atoms, and monocyclic, bicyclic or tricyclic heteroaryl groups having 2 to 25C atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-or 7-membered aryl and heteroaryl groups, wherein, in addition, one or more CH groups may 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, for example, phenyl, biphenyl, terphenyl, [1,1':3',1 ] " ]-terphenyl-2' -yl, naphthyl, anthracenyl, binaphthyl, phenanthryl, pyrene, dihydropyrene,Perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene (spirobifluorene), etc., more preferably 1, 4-phenylene, 4' -biphenylene, 1, 4-terphenylene, etc.

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, 1,2,3, 5-tetrazine or fused groups, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthazole, phenanthroimidazole, pyridoimidazole, pyrazinoimidazole, quinoxalinoimidazole, benzoxazole, naphthazole, anthracenoxazole, phenanthrooxazole, 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, dithiene, isobenzothiophene, dibenzothiophene, benzothiadiazole thiophene, or a combination of these groups. Heteroaryl groups may also be substituted with alkyl, alkoxy, thioalkyl, fluoro, fluoroalkyl, or other aryl or heteroaryl groups.

In the context of the present application, the term "(non-aromatic) alicyclic groups encompasses both saturated rings and heterocyclic groups" both saturated rings, i.e. those containing only single bonds, and partially unsaturated rings, i.e. those which may also contain multiple bonds. The heterocyclic ring contains one or more heteroatoms, preferably selected from Si, O, N, S and Se. The (non-aromatic) alicyclic and heterocyclic groups may be monocyclic, i.e. contain only one ring (e.g. cyclohexane), or polycyclic, i.e. contain multiple rings (e.g. decalin or bicyclooctane). Preference is furthermore given to mono-, bi-or tricyclic groups having 3 to 25C atoms which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-, 7-or 8-membered carbocyclic groups in which, in addition, one or more C atoms may be replaced by Si and/or one or more CH groups may be replaced by N and/or one or more non-adjacent CH groups ₂ The groups may be replaced by-O-and/or-S-. Preferred cycloaliphatic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine; 6-membered radicals, such as cyclohexane, silacyclohexane (siline), tetrahydropyran, tetrahydrothiopyran, 1, 3-dioxane, 1, 3-dithiane, Piperidine; 7-membered groups such as cycloheptane; and condensed groups, e.g. tetralin, decalin, indane, bicyclo [1.1.1]Pentane-1, 3-diyl, bicyclo [2.2.2]Octane-1, 4-diyl, spiro [3.3 ]]Heptane-2, 6-diyl, octahydro-4, 7-methanoindan-2, 5-diyl, more preferably 1, 4-cyclohexylene, 4' -dicyclohexylene, 3, 17-hexadechydro-cyclopenta [ a ]]Phenanthrene, optionally substituted with one or more identical or different groups L. Particularly preferred aryl-, heteroaryl-, alicyclic-and heterocyclic groups are 1, 4-phenylene, 4 '-biphenylene, 1, 4-terphenylene, 1, 4-cyclohexylene, 4' -dicyclohexylene and 3, 17-hexadecano [ a ]]Phenanthrene, optionally substituted with one or more identical or different groups L.

Preferred substituents (L) for the aryl-, heteroaryl-, alicyclic-and heterocyclic groups mentioned above are, for example, solubility promoting groups (e.g. alkyl or alkoxy) and electron withdrawing groups (e.g. fluoro, nitro or nitrile).

Particularly preferred substituents are, for example, halogen, CN, NO ₂ 、CH ₃ 、C ₂ H ₅ 、OCH ₃ 、OC ₂ H ₅ 、COCH ₃ 、COC ₂ H ₅ 、COOCH ₃ 、COOC ₂ H ₅ 、CF ₃ 、OCF ₃ 、OCHF ₂ Or OC (alpha) ₂ F ₅ 。

The above and below "halogen" means F, cl, br or I.

The terms "alkyl", "aryl", "heteroaryl", and the like above and below also encompass 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" denotes an "aryl" group as defined above containing one or more heteroatoms.

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, perfluorohexyl and the like.

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-decyloxy, n-undecoxy, n-dodecoxy.

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

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

Oxaalkyl, i.e. one of CH ₂ The radicals are replaced by-O-, preferably for example straight-chain 2-oxapropyl (= methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3-or 4-oxapentyl, 2-, 3-, 4-or 5-oxahexyl, 2-, 3-, 4-, 5-or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6-or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7-or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-, 7-, 8-or 9-oxadecyl.

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

In general, the term "chiral" is used to describe an object that is non-superimposable on its mirror image.

An "achiral" (achiral) object is the same object as its mirror image.

The terms "chiral nematic" and "cholesteric" are used synonymously in the present application unless explicitly described otherwise.

The term "bimesogenic compound" relates to a compound comprising two mesogenic groups in the molecule. Just as conventional mesogens, they can form many mesophases, depending on their structure. In particular, the bimesogenic compound can induce a second nematic phase when added to a nematic liquid crystal medium. The bimesogenic compounds are also referred to as "dimeric liquid crystals".

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

"alignment" or "orientation" refers to the alignment (orientation ordering) of anisotropic units of a material, such as a small molecule or a fragment of a large molecule, in a common direction called the "alignment direction". In the alignment layer of the liquid crystal material, the liquid crystal director coincides with the alignment direction such that the alignment direction corresponds to the direction of the anisotropy axis of the material.

The term "planar alignment" in, for example, a layer of liquid crystal material means that a proportion of the long molecular axes (in the case of rod-like compounds) or the short molecular axes (in the case of discotic compounds) of the liquid crystal molecules are substantially parallel (about 180 °) to the planar alignment of the layer.

The term "homeotropic alignment" in, for example, a layer of liquid crystal material means that a proportion of the long molecular axes (in the case of rod-like compounds) or the short molecular axes (in the case of discotic compounds) of the liquid crystal molecules are oriented at an angle θ ("tilt angle") of about 80 ° to 90 ° with respect to the plane of the layer.

The term "homogeneous alignment" or "homogeneous alignment" of a liquid crystal material in, for example, a material layer means that the long molecular axes (in the case of rod-like compounds) or the short molecular axes (in the case of discotic compounds) of the liquid crystal molecules are oriented in substantially the same direction. In other words, the lines of the liquid crystal directors are parallel. Unless explicitly specified otherwise, the wavelength of light generally referred to in the present application is 550nm.

The birefringence Δn herein is defined by the following equation:

Δn＝n _e -n _o

wherein n is _e Is of extraordinary refractive index and n _o Is of ordinary refractive index and average refractive index n _av. Given by the following equation.

n _av. ＝[(2n _o ² +n _e ² )/3] ^1/2

Extraordinary refractive index n _e And an ordinary refractive index n _o The Abbe refractometer measurement can be used.

In the present application, the term "dielectrically positive" is used for compounds or components with Δε >3.0, "dielectrically neutral" is used for compounds or components with Δε.ltoreq.3.0 and "dielectrically negative" is used for compounds or components with Δε < -1.5. Delta epsilon is measured at a frequency of 1kHz and at 20 ℃. The dielectric anisotropy of each compound was determined from the results of a 10% solution of each single compound in a nematic host mixture. In the case where the solubility of each compound in the host medium is less than 10%, then its concentration is reduced by one half until the resulting medium is stable enough to at least allow its properties to be determined. Preferably, however, the concentration is maintained at least 5% to maintain as high a result significance as possible. The capacitance of the test mixtures was measured in a cell having both homeotropic and homeotropic orientations. The thickness of the two types of cartridges was about 20 μm. The applied voltage is a rectangular wave with a frequency of 1kHz and the root mean square value is typically 0.5V to 1.0V; however, it is always selected to be below the capacitance threshold of the respective test mixture.

Delta epsilon is defined as (epsilon) _|| -ε _⊥ ) And epsilon _av. Is (epsilon) _|| +2ε _⊥ )/3. The dielectric permittivity of a compound is determined from the change in the individual values of the host medium after the addition of the compound of interest. Extrapolated to a concentration of 100% of the compound of interest. Typical host media are ZLI-4792 or BL-087, both available from Merck, darmstadt.

With respect to the present application,

is->Represents trans-1, 4-cyclohexylene,

is->

Represents 1, 4-phenylene.

Furthermore, the definitions as given in C.Tschierske, G.Pelzl and S.Diele, angew.Chem.2004,116,6340-6368 should apply to the undefined terms in connection with liquid crystal materials in the present application.

Detailed description of the preferred embodiments

The present application relates to compounds of the formula I,

R ¹¹ -A ¹¹ (-Z ¹¹ -A ¹² -) _p -X ¹¹ -Sp ¹¹ -X ¹² -(A ¹³ -Z ¹² -) _q A ¹⁴ -R ¹² I

wherein,,

R ¹¹ represents a linear or branched alkyl radical in which one or more non-adjacent and non-terminal CH ₂ The radicals can be replaced, independently of one another, by-O-; -S-, -NH-, -N (CH) ₃ ) -, -CO-, -COO-; -OCO-, -O-CO-O-, -S-CO-, -CO-S-, -ch=ch-, -CH=CF-, -CF=CF-, or-C≡C-being replaced in such a way that the oxygen atoms are not directly connected to each other,

R ¹² represents F, cl, CN and NCS, or a linear or branched alkyl radical which may be unsubstituted, monosubstituted or polysubstituted by halogen or CN, wherein one or more non-adjacent and non-terminal CH ₂ The radicals can be replaced, independently of one another, by-O-; -S-, -NH-, -N (CH) ₃ ) -, -CO-, -COO-; -OCO-, -O-CO-O-, -S-CO-, -CO-S-, -ch=ch-, -CH=CF-, -CF=CF-, or-C≡C-being replaced in such a way that the oxygen atoms are not directly connected to each other,

preferably F, cl, CN, can be unsubstituted, mono-or polysubstituted by halogen or CN, straight-chain or branched alkyl, alkenyl or alkoxy,

more preferably F, CN or OCF ₃ ，

A ¹¹ Representation of

A ¹² To A ¹⁴ Each occurrence is independently 1, 4-phenylene, wherein, in addition, one or more CH groups may be replaced by N; trans-1, 4-cyclohexylene, wherein, in addition, one or two non-adjacent CH ₂ The groups may be replaced by O and/or S; 1, 4-cyclohexylene; naphthalene-2, 6-diyl; decahydro-naphthalene-2, 6-diyl; 1,2,3, 4-tetrahydro-naphthalene-2, 6-diyl, all of which may be unsubstituted, mono-, di-, tri-or tetra-substituted with: F. cl, CN or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl, wherein one or more H atoms may be replaced by F or Cl,

preferably, each occurrence is independently 1, 4-phenylene, wherein, in addition, one or more CH groups may be replaced by N, or trans-1, 4-cyclohexylene, wherein, in addition, one or two non-adjacent CH groups ₂ The groups may be replaced by O and/or S, and both ring groups may be unsubstituted, monosubstituted, disubstituted, trisubstituted or tetrasubstituted by: F. cl, CN or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl, wherein one or more H atoms may be replaced by F or Cl,

Z ²¹ z is as follows ²² Independently at each occurrence a single bond, -COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-OCF ₂ -、-CF ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, optionally substituted with one or more of F, S and/or Si,

preferably a single bond, is used,

p and q are each independently 0, 1, 2, 3 or 4, preferably 0, 1, 2 or 3, and most preferably 1 or 2.

Sp ¹¹ Is a spacer group comprising 1, 3 or 5 to 40C atoms, wherein one or more non-adjacent and non-terminal CH ₂ The radicals may also be substituted by-O-; -S-, -NH-, -N (CH) ₃ )-、-CO-、-O-CO-、-S-CO-、-O-COO-、-CO-S-、-CO-O-、-CF ₂ -、-CF ₂ O-、-OCF ₂ - -C (OH) - -, - -CH (alkyl) - -, - -CH (alkenyl) - -, - -CH (alkoxy) - -, - -CH (oxaalkyl) - -, - -CH=CH- -or- -C≡C- -is replaced in such a way that no two O-atoms are adjacent to each other and in such a way that no two groups selected from- -O- -CO- -, - -S- -CO- -, - -O- -COO- -, - -CO- -S- -, - -CO- -O- -and- -CH=CH- -are adjacent to each other, preferably- - (CH) ₂ ) _n Where n is an integer from 1, 3 or 5 to 15, more preferably from 3 to 11, most preferably an odd integer (i.e., 3, 5, 7, 9 or 11),

X ¹¹ And X ¹² Are independently selected from the group consisting of single bonds, -CO-O-, -O-CO-; -O-COO-, -O-, -ch=ch-, -c≡c-, -CF ₂ -O-、-O-CF ₂ -、-CF ₂ -CF ₂ -、-CH ₂ -O-、-O-CH ₂ -, -CO-S-, -S-CO-; -CS-S-, -S-CS-, -S-CSS-and-S-, wherein at-X ¹¹ -Sp ¹ -X ¹² In each of which there are two O atoms, two-CH=CH-groups and two groups selected from-O-CO-, -S-CO-, -O-COO-; radicals of-CO-S-and-CO-O-, the clusters are not directly connected to each other.

If R is ¹¹ Or R is ¹² Is alkyl or alkoxy, it may be straight or branched. It is preferably straight-chain and has 2, 3, 4, 5, 6, 7 or 8 carbon atoms, and is therefore preferably, for example, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy or octoxy, and furthermore methyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, nonoxy, decyloxy, undecyloxy, dodecoxy, tridecyloxy or tetradecyloxy.

If R is ¹¹ Or R is ¹² Alkenyl, it may be straight or branched. It is preferably straight-chain, having up to 15C atoms, and more preferably ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl and the corresponding isomers.

In a device having two non-polesIn the case of compounds of a sexual group, R ¹¹ Or R is ¹² Preferably alkenyl or alkynyl having up to 15 carbon atoms, preferably alkenyl, and another preferably alkyl, alkenyl or alkynyl, most preferably alkyl or alkenyl having 2 to 15 carbon atoms, or alkoxy having 1 to 15, preferably 2 to 15 carbon atoms.

In addition, containing achiral branching groups R ¹¹ And/or R ¹² The compounds of formula I of (a) may sometimes be important, for example, due to a reduced tendency to crystallize. Branched groups of this type typically do not contain more than one branch. Preferred achiral branched groups are isopropyl, isobutyl (=methylpropyl), isopentyl (=3-methylbutyl), isopropoxy, 2-methyl-propoxy and 3-methylbutoxy.

In the case of compounds having terminal polar groups, R ¹² Selected from CN, NO ₂ Halogen, OCH ₃ 、OCN、SCN、COR ^x 、COOR ^x Or mono-, oligo-or polyfluorinated alkyl or alkoxy groups having 1 to 4C atoms. R is R ^x Is an optionally fluorinated alkyl group having 1 to 4, preferably 1 to 3C atoms. Halogen is preferably F or Cl.

Particularly preferably, R in formula I ¹² Selected from H, alkenyl, F, cl, CN, NO ₂ 、OCH ₃ 、COCH ₃ 、COC ₂ H ₅ 、COOCH ₃ 、COOC ₂ H ₅ 、CF ₃ 、C ₂ F ₅ 、OCF ₃ 、OCHF ₂ And OC ₂ F ₅ In particular ethenyl, propenyl, butenyl, F, cl, CN, CF ₃ 、OCH ₃ And OCF (optical fiber) ₃ In particular propenyl, butenyl, F, CN and OCF ₃ 。

Preferred groups-A comprising only 6-membered rings are listed below ¹¹ (-Z ¹¹ -A ¹² -) _p Or a smaller group in MG-11. For simplicity, phe in these radicals is 1, 4-phenylene and PheL is 1, 4-phenylene substituted by 1 to 4 radicals L, where L is preferably F, cl, CN, OH, NO ₂ Or optionally fluorinated alkyl, alkoxy or alkanoyl groups having 1 to 7 carbon atoms, very preferablySelect F, cl, CN, OH, NO ₂ 、CH ₃ 、C ₂ H ₅ 、OCH ₃ 、OC ₂ H ₅ 、COCH ₃ 、COC ₂ H ₅ 、COOCH ₃ 、COOC ₂ H ₅ 、CF ₃ 、OCF ₃ 、OCHF ₂ 、OC ₂ F ₅ In particular F, cl, CN, CH ₃ 、C ₂ H ₅ 、OCH ₃ 、COCH ₃ And OCF (optical fiber) ₃ Most preferably F, cl, CH ₃ 、OCH ₃ And COCH (chip on board) ₃ And Cyc represents

The list includes the sub-formulas shown below,

wherein,,

cyc is

Preferably is

Phe is a group selected from the group consisting of 1, 4-phenylene,

PheL is 1, 4-phenylene which is substituted by one, two or three fluorine atoms, by one or two Cl atoms or by one Cl atom and one F atom, and

z has the formula I ¹¹ And if it occurs twice, at least one is preferably selected from the group consisting of-C.ident.C-, C=C-, -COO-, -OCO-,O-CO-O-、-OCH ₂ -、-CH ₂ O-、-OCF ₂ -or-CF ₂ O-。

Particularly preferred are those in which Z independently in each case has Z as given in formula I ¹¹ And if two occurrences, preferably one of Z is-COO-, -OCO-, -CH ₂ -O-、-O-CH ₂ -、-CF ₂ -O-or-O-CF ₂ -。

Preferably, MG-11 is selected from the subformulae that do not contain two groups Z, more preferably MG-11-2 to MG-11-13, and even more preferably MG-11-2 or MG-11-3.

Preferred- (A) containing only 6-membered rings are listed below ¹³ -Z ¹² -) _q A ¹⁴ Or a smaller group of MG-12 groups. For simplicity, phe in these radicals is 1, 4-phenylene and PheL is 1, 4-phenylene substituted by 1 to 4 radicals L, where L is preferably F, cl, CN, OH, NO ₂ Or optionally fluorinated alkyl, alkoxy or alkanoyl groups having 1 to 7 carbon atoms, very preferably F, cl, CN, OH, NO ₂ 、CH ₃ 、C ₂ H ₅ 、OCH ₃ 、OC ₂ H ₅ 、COCH ₃ 、COC ₂ H ₅ 、COOCH ₃ 、COOC ₂ H ₅ 、CF ₃ 、OCF ₃ 、OCHF ₂ 、OC ₂ F ₅ In particular F, cl, CN, CH ₃ 、C ₂ H ₅ 、OCH ₃ 、COCH ₃ And OCF (optical fiber) ₃ Most preferably F, cl, CH ₃ 、OCH ₃ And COCH (chip on board) ₃ And CHex is 1, 4-cyclohexylene. The list includes the sub-types shown below,

wherein the method comprises the steps of

CHex is a 1, 4-cyclohexylene group, preferably a trans-1, 4-cyclohexylene group,

phe is a group selected from the group consisting of 1, 4-phenylene,

z has Z given in part II ¹¹ One of the meanings, and if two occurrences, at least one is preferably selected from the group consisting of-C.ident.C-, -C. = C-, -COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-OCF ₂ -or-CF ₂ O-。

In the preferred sub-formulae MG-11 and MG-12 given above,

PheL preferably represents a group

Radicals (C)Very preferably means +.>And

wherein L is preferably F, cl, CH ₃ 、OCH ₃ And COCH (chip on board) ₃ 。

Preferably, MG-12 is selected from the subformulae that do not contain two groups Z, more preferably from MG-12-1 to MG-12-38, even more preferably from MG-12-4 or MG-12-38, especially MG-12-9 to MG-12-12 or MG-12-32 to MG-12-38.

Particularly preferred are compounds of formula I wherein the corresponding pairs of mesogenic groups MG-11 and MG-12 each comprise two or three six-membered rings, more preferably MG-11 and MG-12 each comprise two six-membered rings, or MG-11 comprises two six-membered rings and MG-12 comprises three six-membered rings, or MG-11 comprises three six-membered rings and MG-12 comprises two six-membered rings.

Further preferred are compounds of formula I wherein

Sp ¹¹ Represents- (CH) ₂ ) _n -, and

n is an integer from 1 to 15, wherein one or more-CH ₂ The groups may be replaced by-CO-, preferably odd, more preferably 3, 5, 7, 9, 11 or 13,

further preferred compounds of formula I are those wherein,

-X ¹¹ -Sp ¹¹ -X ¹² -is-Sp ¹¹ -、-Sp ¹¹ -O-、-Sp ¹¹ -CO-O-、-Sp ¹¹ -O-CO-、-CO-O-Sp ¹¹ 、-O-CO-Sp ¹¹ 、-O-Sp ¹¹ -、-O-Sp ¹¹ -CO-O-、-O-Sp ¹¹ -O-CO-、-O-CO-Sp ¹¹ -O-、-O-CO-Sp ¹¹ -O-CO-、-CO-O-Sp ¹¹ -O-or-CO-O-Sp ¹¹ -CO-O-, provided that at-X ³¹ -Sp ³ -X ³² No two O-atoms are adjacent to each other, no two-ch=ch-groups are adjacent to each other and no two groups selected from-O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-and-ch=ch-are adjacent to each other.

Further preferred compounds of formula I are selected from the following substructures,

wherein,,

l in each case independently of one another represents F, cl, CH ₃ 、OCH ₃ And COCH (chip on board) ₃ Preferably, the composition of F,

r represents an integer of 0 to 4, preferably 0, 1 or 2,

R ¹¹ represents alkyl or alkoxy, which may be straight-chain or branched having 2, 3, 4, 5, 6, 7 or 8 carbon atoms,

R ¹² represents CN, NO ₂ 、F、OCH ₃ 、OCN、SCN、COR ^x 、COOR ^x Or mono-, oligo-or polyfluorinated alkyl or alkoxy groups having 1 to 4 carbon atoms,

R ^x is an optionally fluorinated alkyl group having 1 to 4, preferably 1 to 3, carbon atoms, and

n represents 3, 5, 7, 9, 11 or 13.

R ¹¹ represents alkyl which may be straight-chain or branched with 2, 3, 4, 5, 6, 7 or 8 carbon atoms, preferably straight-chain alkyl with 3, 4 or 5 carbon atoms,

R ¹² represents CN, F, CF ₃ Or OCF (optical clear) ₃ Preferably CN or F, and

n represents 3, 5, 7, 9, 11 or 13, preferably 7, 9 or 11.

The compounds of the formula I can be synthesized according to methods known per se and described in the standard literature of organic chemistry or in a manner analogous to this method, for example as described in Houben-Weyl, methoden der organischen Chemie, thieme-Verlag, stuttgart.

In a preferred embodiment, the compounds of formula I and their subformulae can be synthesized according to or similar to the following synthesis schemes 1 or 2:

synthesis scheme 1:

wherein L, R, R ¹¹ And R is ¹² Has one of the meanings given above, and n represents an integer from 0 to 12.

Synthesis scheme 2:

wherein L, R, R ¹¹ And R is ¹² Having one of the meanings given above, n represents an integer from 1 to 11.

For example, one of the main advantages of using the compounds of formula I in liquid-crystalline media for flexoelectric applications is to improve the switching speed in ULH (uniformly aligned helix) geometries, especially at temperatures below 35 ℃. Benefits are also observed in terms of phase range, in terms of increased isotropic-to-nematic clearing point, and in terms of reduced nematic-to-nematic twist bend transition temperature below room temperature.

The invention therefore also relates to the use of the compounds of the formula I in liquid-crystalline media and to liquid-crystalline media comprising one or more compounds of the formula I per se.

In a preferred embodiment, the liquid-crystalline medium according to the invention comprises one or more compounds of the formula II,

R ²¹ -A ²¹ -A ²² -(CH ₂ ) _a -A ²³ -A ²⁴ -R ²² II

wherein,,

R ²¹ and R is ²² Independently represent H, F, cl, CN, NCS or a linear or branched alkyl group, which may be unsubstituted, substituted Halogen or CN monosubstituted or polysubstituted, one or more non-adjacent CH(s) ₂ The radicals may also be replaced, independently of one another, by-O-, -S-, -NH-, -N (CH) ₃ ) - -S-CO-, -CO-S-, -ch=ch-, -CH=CF-, -CF=CF-, or-C≡C-in such a way that the oxygen atoms are not directly connected to each other, preferably F, cl, CN, straight-chain or branched alkyl or alkoxy, which may be unsubstituted, monosubstituted or polysubstituted by halogen or CN,

more preferably F, CN or OCF ₃ ，

A ²¹ To A ²⁴ Independently for each occurrence, aryl-, heteroaryl-, alicyclic-and heterocyclic radicals, preferably 1, 4-phenylene, wherein, in addition, one or more CH groups may be replaced by N, 1, 4-bicyclo- (2, 2) -octylene, naphthalene-2, 6-diyl, decahydro-naphthalene-2, 6-diyl, 1,2,3, 4-tetrahydro-naphthalene-2, 6-diyl, cyclobutane-1, 3-diyl, spiro [3.3 ]]Heptane-2, 6-diyl or dispiro [3.1.3.1]Decane-2, 8-diyl, all of which may be unsubstituted, monosubstituted, disubstituted, trisubstituted or tetrasubstituted by F, cl, CN or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl, wherein one or more H atoms may be replaced by F or Cl,

more preferably each occurrence is independently 1, 4-phenylene, wherein, in addition, one or more CH groups may be replaced by N, or trans-1, 4-cyclohexylene, wherein, in addition, one or two non-adjacent CH groups ₂ The radicals may be replaced by O and/or S, the two ring groups may be unsubstituted or mono-, di-, tri-or tetrasubstituted by F, cl, CN or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl, where one or more H atoms may be replaced by F or Cl,

a represents an integer of 1 to 15, preferably an odd (i.e., non-even) integer, more preferably 3, 5, 7, 9 or 11.

Preferred compounds of formula II are selected from the group (-A) wherein ²¹ -A ²² -) and (-A) ²³ -A ²⁴ (-) are each independently selected from the group consisting of compounds,

wherein,,

phe in these radicals is 1, 4-phenylene,

PheL is 1, 4-phenylene substituted by 1 to 4 radicals L, where L is preferably F, cl, CN, OH, NO ₂ Or optionally fluorinated alkyl, alkoxy or alkanoyl groups having 1 to 7 carbon atoms, very preferably F, cl, CN, OH, NO ₂ 、CH ₃ 、C ₂ H ₅ 、OCH ₃ 、OC ₂ H ₅ 、COCH ₃ 、COC ₂ H ₅ 、COOCH ₃ 、COOC ₂ H ₅ 、CF ₃ 、OCF ₃ 、OCHF ₂ 、OC ₂ F ₅ In particular F, cl, CN, CH ₃ 、C ₂ H ₅ 、OCH ₃ 、COCH ₃ And OCF (optical fiber) ₃ Most preferably F, cl, CH ₃ 、OCH ₃ And COCH (chip on board) ₃ A kind of electronic device

Cyc is 1, 4-cyclohexylene.

Preferred are those wherein the group in formula II (R ²¹ -A ²¹ -A ²² -) and (-A) ²³ -A ²⁴ -R ²² ) The same or mirror image compounds of formula II.

Also preferred are those wherein in formula II (R ²¹ -A ²¹ -A ²² -) and (-A) ²³ -A ²⁴ -R ²² ) Different compounds of formula II.

Preferred compounds of formula II are shown below:

wherein the method comprises the steps of

n represents an integer of 1 to 15, preferably an odd (i.e., non-even) integer, more preferably 3, 5, 7, 9 or 11.

The compounds of the formula II can be synthesized according to methods known per se and described in the standard literature of organic chemistry or in a manner analogous to this method, for example as described in Houben-Weyl, methoden der organischen Chemie, thieme-Verlag, stuttgart. Preferred methods of preparation are available from WO2013/004333A 1.

In the mixtures according to the invention, the use of compounds of the formula II in addition to compounds of the formula I is particularly useful for further improving the switching speed while maintaining a good phase range and advantageous e/K values.

In a preferred embodiment, the liquid-crystalline medium according to the invention comprises one or more compounds of the formula III,

R ³¹ -A ³¹ -A ³² -(A ³³ ) _b -Z ³¹ -(CH ₂ ) _c -Z ³² -A ³⁴ -A ³⁵ -A ³⁶ -R ³² III

wherein the method comprises the steps of

R ³¹ And R is ³² Each independently having the formula II for R ²¹ And R is ²² One of the meanings given in the description,

A ³¹ to A ³⁶ Each independently having the formula II for A ²¹ To A ²⁴ One of the meanings given in the description,

Z ³¹ and Z ³² Each occurrence is independently-COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, which is optionally substituted by one or more of F, S and/or Si, preferably-COO-, -OCO-, or-O-CO-O-, more preferably-COO-, or-OCO-,

b represents an integer of 1 to 15, preferably an odd (i.e., non-even) integer, more preferably 3, 5, 7 or 9, and

c represents 0 or 1, preferably 0.

Preferred compounds of formula III are selected from the group wherein c represents 0 and a group (-A) ³¹ -A ³² (-) is selected from the group of compounds MG1 to MG4 as given above.

Further preferred compounds of formula III are selected from the group wherein c represents 1 and a group (-A) ²⁴ -A ²⁵ -A ²⁶ -) and (-A) ²¹ -A ²² -A ²³ (-) are each independently selected from the following groups:

wherein the method comprises the steps of

Phe, pheL and L have one of the meanings given above for the groups MG-1 to MG-4.

Further preferred compounds of formula III are selected from the group wherein c represents 0 and a group (-A) ²¹ -A ²² (-) is selected from MG1 to MG4 and groups (-A) therein as given above ²⁴ -A ²⁵ -A ²⁶ (-) is selected from MG5 to MG 11.

Particularly preferred compounds of formula III are selected from the group of compounds of the formula,

the compounds of the formula III can be synthesized according to methods known per se and described in the standard literature of organic chemistry or in a manner analogous to this method, for example as described in Houben-Weyl, methoden der organischen Chemie, thieme-Verlag, stuttgart.

In the mixtures according to the invention, the reuse of the compounds of the formula III in addition to the compounds of the formula I is particularly useful for obtaining high stability, advantageous high-definition bright spots and broad Xiang Fan-circle and low occurrence of nematic twist-bend phases.

In a further preferred embodiment, the liquid-crystalline medium according to the invention comprises one or more compounds of the formula IV,

R ⁴¹ -A ⁴¹ -A ⁴² -Z ⁴¹ -(CH ₂ ) _d -Z ⁴² -A ⁴³ -A ⁴⁴ -R ⁴² IV

Wherein the method comprises the steps of

R ⁴¹ And R is ⁴² Each independently has the formula II above for R ²¹ One of the meanings given in the description,

A ⁴¹ to A ⁴⁴ Each independently having the formula II above for A ²¹ One of the meanings given in the description,

Z ⁴¹ and Z ⁴² Each occurrence is independently-COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, which is optionally substituted by one or more of F, S and/or Si, preferably-COO-, -OCO-, or-O-CO-O-, more preferably-COO-, or-OCO-.

d represents an integer of 1 to 15, preferably an odd (i.e., non-even) integer, and more preferably 3, 5, 7 or 9.

Preferred compounds of formula IV are selected from the group (-A) wherein ⁴¹ -A ⁴² -) and (-A) ⁴³ -A ⁴⁴ (-) are each independently selected from the compounds of the groups MG1 to MG4 as given above.

Particularly preferred compounds of formula IV are selected from the following compounds:

symmetrical formulas (IVa and IVb):

asymmetric formula (IVc):

the compounds of the formula IV are known or can be synthesized according to methods known per se and described in the standard works of organic chemistry or in a manner analogous to this method, for example as described in Houben-Weyl, methoden der organischen Chemie, thieme-Verlag, stuttgart.

In the mixtures according to the invention, the reuse of the compounds of the formula IV in addition to the compounds of the formula I is particularly useful for reducing the nematic torsional bending phase while maintaining a favorable e/K value.

In a further preferred embodiment, the liquid-crystalline medium according to the invention also comprises one or more compounds of the formula V,

R ⁵¹ -A ⁵¹ -Z ⁵¹ -(CH ₂ ) _e -Z ⁵² -A ⁵² -(A ⁵³ ) _f -R ⁵² V

wherein the method comprises the steps of

R ⁵¹ And R is ⁵² Each independently has the formula II above for R ²¹ One of the meanings given in the description,

A ⁵¹ to A ⁵³ Each independently having the formula II above for A ²¹ One of the meanings given in the description,

Z ⁵¹ and Z ⁵² Each occurrence is independently-COO-, -OCO-, -O-CO-O-、-OCH ₂ -、-CH ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, which is optionally substituted by one or more of F, S and/or Si, preferably-COO-, -OCO-, or-O-CO-O-, more preferably-COO-, or-OCO-.

e represents an integer of 1 to 15, preferably an odd (i.e., non-even) integer, and more preferably 3, 5, 7 or 9 and

f represents 0 or 1.

Particularly preferred are those wherein A ⁵¹ A compound of formula V selected from the mirror images of formulae Va 'to Vf' and formulae Vd 'and Ve' below:

preferably, R in formula V ⁵¹ And R is ⁵² Selected from H, F, cl, CN, NO ₂ 、OCH ₃ 、COCH ₃ 、COC ₂ H ₅ 、COOCH ₃ 、COOC ₂ H ₅ 、CF ₃ 、C ₂ F ₅ 、OCF ₃ 、OCHF ₂ And OC ₂ F ₅ In particular H, F, cl, CN, OCH ₃ And OCF (optical fiber) ₃ In particular H, F, CN and OCF ₃ 。

Preferred compounds of formula V are selected from compounds of formulas VA to VD, preferably compounds of formulas VA and/or VC, most preferably compounds of formula VC,

wherein,,

LG ⁵¹ is Z ⁵¹ -(CH ₂ ) _Z -Z ⁵² ，

(F) ₀ Represents H, and

(F) ₁ and represents F.

And other parameters have the respective meanings given above, including the preferred meanings.

Preferably Z ⁵¹ -(CH ₂ ) _Z -Z ⁵² represents-O-CO- (CH) ₂ ) _n -CO-O-、-O-(CH ₂ ) _n -O-or- (CH) ₂ ) _n -, more preferably-O-CO- (CH) ₂ ) _n CO-O-, wherein n represents 3, 5, 7 or 9,

particularly preferred compounds of formula VA are selected from compounds of formulae VA-1 to VA-3,

wherein the parameters have the respective meanings given above, including the preferred meanings.

Particularly preferred compounds of formula VB are selected from the group consisting of compounds of formulae VB-1 to VB-3,

Very particular preference is given to compounds of the formula VC. And these particularly preferred compounds are selected from the compounds of the formulae VC-1 to VC-3,

The compounds of the formula V can be synthesized according to methods known per se and described in the standard literature of organic chemistry or in a manner analogous to this method, for example as described in Houben-Weyl, methoden der organischen Chemie, thieme-Verlag, stuttgart. Preferred methods of preparation are disclosed, for example, in WO 2015/036079 A1.

In a further preferred embodiment, the liquid-crystalline medium according to the invention additionally comprises one or more compounds of the formula VI,

R ⁶¹ -A ⁶¹ -A ⁶² -(CH ₂ ) _g -Z ⁶¹ -A ⁶³ -A ⁶⁴ -(A ⁶⁵ ) _h -R ⁶² VI

wherein,,

R ⁶¹ and R is ⁶² Each independently has the formula II above for R ²¹ One of the meanings given in the description,

A ⁶¹ To A ⁶⁴ Each independently having the formula II above for A ²¹ One of the meanings given in the description,

Z ⁶¹ represents-O-, -COO-, -OCO- -O-CO-O-, -OCH ₂ -、-CH ₂ O、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, optionally substituted with one or more of F, S and/or Si, preferably-O-, -COO-; -OCO-or-O-CO-O-, -OCO-or-O-CO-O-,

h represents 0 or 1, and

g represents an integer of 1 to 15, preferably an odd (i.e., non-even) integer, more preferably 3, 5, 7 or 9.

Preferred compounds of formula VI are selected from the group (-A) wherein ⁶¹ -A ⁶² -) and (-A) ⁶³ -A ⁶⁴ (-) are each independently selected from the compounds of the groups MG1 to MG4 given above.

Further preferred is a compound of formula VI wherein h represents 0 and a group (-A) ⁶¹ -A ⁶² -) and (-A) ⁶³ -A ⁶⁴ -(A ⁶⁵ ) _h ) Compounds of formula VI which are not identical or mirror images or in which h represents 1.

Particularly preferred compounds of formula VI are selected from the group consisting of compounds of the following formulas,

the compounds of the formula VI can be synthesized according to methods known per se and described in the standard literature of organic chemistry or in a manner analogous to this method, for example as described in Houben-Weyl, methoden der organischen Chemie, thieme-Verlag, stuttgart. Preferably, the compound of formula VI is synthesized according to or in a similar manner to the method disclosed in, for example, WO2014/005672A 1.

In the mixtures according to the invention, the reuse of the compounds of the formula VI in addition to the compounds of the formula I is particularly useful for obtaining high-definition bright spots and advantageous e/K values.

In a further preferred embodiment, the liquid-crystalline medium according to the invention further comprises one, two, three or more compounds of the formula VII,

R ⁷¹ -A ⁷¹ -Z ⁷¹ -A ⁷² -(Z ⁷² -A ⁷³ ) _i -(CH ₂ ) _j -(A ⁷⁴ -Z ⁷³ -) _k -A ⁷⁵ -Z ⁷⁴ -A ⁷⁶ -R ⁷² VII

wherein the method comprises the steps of

R ⁷¹ And R is ⁷² Each independently has the formula II above for R ²¹ One of the meanings given in the description,

A ⁷¹ to A ⁷⁶ Each independently having the formula II above for A ²¹ One of the meanings given in the description,

Z ⁷¹ to Z ⁷⁴ Each independently represents-COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-OCF ₂ -、-CF ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -、-CH＝CH-、-CF＝CF-、-CH=ch-COO-, -OCO-ch=ch-, or-c≡c-, optionally substituted by one or more of F, S and/or Si, or a single bond, preferably-COO-, -OCO-, -O-CO-O-, -OCF ₂ -、-CF ₂ O-or a single bond, more preferably-COO-, -OCO-, -OCF ₂ -、-CF ₂ O-or a single bond,

provided that Z ⁷¹ To Z ⁷⁴ Is not a single bond,

j represents an integer of 1 to 15, preferably an odd (i.e., non-even) integer, more preferably 3, 5, 7 or 9, and

i and k each independently represent 0 or 1.

Preferred compounds of formula VII are selected from the group consisting of wherein-A ⁷¹ -Z ⁷¹ -A ⁷² -(Z ⁷² -A ⁷³ ) _i -、-(A ⁷⁴ -Z ⁷³ -) _k -A ⁷⁵ -Z ⁷⁴ -A ⁷⁶ At least one compound selected from the group consisting of MGa to MGn groups and mirror images thereof,

wherein,,

wherein L is, independently of one another, preferably F, cl, CN or optionally fluorinated alkyl, alkoxy or alkanoyl having 1 to 7 carbon atoms, very preferably F, cl, CN, CH ₃ 、C ₂ H ₅ 、OCH ₃ 、OC ₂ H ₅ 、COCH ₃ 、COC ₂ H ₅ 、COOCH ₃ 、COOC ₂ H ₅ 、CF ₃ 、OCF ₃ 、OCHF ₂ 、OC ₂ F ₅ In particular F, cl, CN, CH ₃ 、C ₂ H ₅ 、OCH ₃ 、COCH ₃ And OCF (optical fiber) ₃ Most preferably F, cl, CH ₃ 、OCH ₃ And COCH (chip on board) ₃ And r is, independently at each occurrence, 0, 1, 2,3 or 4, preferably 0, 1 or 2.

In these preferred formulae, the radicalsVery preferably, the expression +.> And +.>

Further preferred are those wherein the group-A in formula VII ⁷¹ -Z ⁷¹ -A ⁷² -(Z ⁷² -A ⁷³ ) _i -and- (A) ⁷⁴ -Z ⁷³ -) _k -A ⁷⁵ -Z ⁷⁴ -A ⁷⁶ -the same or mirror image compound of formula VII, provided that Z ⁷¹ To Z ⁷⁴ Is not a single bond.

Further preferred are compounds of formula VII wherein i and k both represent 1, more preferably one of i and k represents 0 and the other represents 1, most preferably both i and k represent 0.

Particularly preferred compounds of formula VII are selected from the group of compounds of the formula,

wherein R is ⁷¹ And R is ⁷² Each independently represents F or CN.

The compounds of the formula VII can be synthesized according to methods known per se and described in the standard literature of organic chemistry or in a manner analogous to this, for example as described in Houben-Weyl, methoden der organischen Chemie, thieme-Verlag, stuttgart. Preferably, the compounds of formula VII are synthesized according to or similar to the methods disclosed in, for example, WO2013/174478 A1.

In a further preferred embodiment, the medium according to the invention optionally comprises one or more chiral dopants, in particular when used in an electrobending device.

Chiral compounds induce a chiral compound with a pitch (P ₀ ) The pitch is inversely proportional to the concentration (c) of chiral material used in the first approximation. The proportionality constant of this dependence is called the Helical Twisting Power (HTP) of the chiral species and is defined by the following equation:

HTP≡1/(c·P ₀ ) (1)

wherein the method comprises the steps of

c is the concentration of the chiral compound.

For example, a uniform horizontal helical texture is achieved using chiral nematic liquid crystals having a short pitch typically in the range of 0.2 μm to 1 μm, preferably 1.0 μm or less, in particular 0.5 μm or less, which are unidirectionally aligned with their helical axes parallel to the substrates (e.g. glass plates) in the liquid crystal cell. In this configuration, the helical axis of the chiral nematic liquid crystal is equivalent to the optical axis of the birefringent plate.

Preferred are chiral dopants with high Helical Twisting Power (HTP), especially those disclosed in WO 98/00428.

Chiral dopants which are generally used are, for example, the commercially available R/S-5011, CD-1, R/S-811 and CB-15 (from Merck KGaA, darmstadt, germany).

In another preferred embodiment, the chiral dopant is preferably selected from the group consisting of formula VIII,

and/or a compound of the formula XI,

including the individual (S, S) enantiomers,

wherein E and F are each independently 1, 4-phenylene or trans-1, 4-cyclohexylene, v is 0 or 1, Z ⁰ is-COO-, -OCO-, -CH ₂ CH ₂ -or a single bond, and R is an alkyl, alkoxy or alkanoyl group having 1 to 12C atoms.

Compounds of formula VIII and their synthesis are described in WO 98/00428. Compounds of formula IX and their synthesis are described in GB 2,328,207.

The chiral dopants R/S-5011 and the compounds of the formulae VIII and IX described above exhibit very high Helical Twisting Power (HTP) and are therefore particularly useful for the purposes of the invention.

The liquid-crystalline medium preferably comprises preferably 1 to 5, in particular 1 to 3, very preferably 1 or 2 chiral dopants, which are preferably selected from the above-mentioned formulae VIII and/or IX and/or R-5011 or S-5011, very preferably the chiral compounds are R-5011, S-5011.

The amount of chiral compound in the liquid-crystalline medium is preferably from 0.1 to 15% by weight, in particular from 0.5 to 10% by weight, very preferably from 1 to 5% by weight, of the total mixture.

Preferably, the liquid crystal medium comprises one or more nematic liquid crystal compounds selected from the group of compounds shown below:

wherein,,

R ^2A represents H, alkyl or alkoxy having 1 to 15 carbon atoms, wherein, in addition, one or more CH of these groups ₂ The radicals may each be, independently of one another, substituted 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, and wherein, in addition, one or more H atoms may be replaced by halogen,

L ¹ and L ² Each independently of the other represents F, cl, CF ₃ Or CHF ₂ Preferably, each represents F,

Z ² and Z ^2' Each independently of the other represents a single bond, -CH ₂ CH ₂ -、-CH＝CH-、-C≡C-、-CF ₂ O-、-OCF ₂ -、-CH ₂ O-、-OCH ₂ -、-COO-、-OCO-、-C ₂ F ₄ -, -cf=cf-, or-ch=chch ₂ O-，

p represents 0, 1 or 2,

q represents either 0 or 1 and,

(O)C _v H _2v+1 representing OC _v H _2v+1 Or C _v H ₂₊₁ A kind of electronic device

V represents 1 to 6.

The liquid-crystalline medium may contain other additives, such as stabilizers, inhibitors, surface-active compounds, lubricants, wetting agents, dispersants, hydrophobing agents, binders, flow improvers, defoamers, deaerators, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments or nanoparticles, in usual concentrations. The total concentration of these other ingredients is in the range of 0.1% to 10%, preferably 0.1% to 6%, based on the total mixture. The concentration of each compound used is preferably in the range of 0.1% to 3% each.

The concentration of these additives and the like are not considered in terms of the concentration values and ranges of the liquid-crystalline components and compounds of the liquid-crystalline medium in the present application. The same applies to the concentration of the dichroic dye used in the mixture, which is not counted when the concentration of the component or compound of the host medium is specified. The concentration of each additive is always given relative to the final doped mixture.

In general, the total concentration of all compounds in the medium according to the application is 100%.

The liquid-crystalline medium of the application consists of several, preferably from 2 to 40, more preferably from 3 to 30 and most preferably from 4 to 25 compounds.

The media according to the application exhibit a high elastic constant k ₁₁ A value and a high bending modulus e. The liquid-crystalline medium preferably exhibits k ₁₁ Less than or equal to 100pN, preferably less than or equal to 20pN.

The liquid-crystalline medium preferably exhibits k ₃₃ Less than or equal to 100pN, preferably less than or equal to 15pN.

The liquid-crystalline medium preferably exhibits a bend coefficient I e ₁₁ And-0.2 pC/m or more, preferably 1pC/m or more.

The liquid-crystalline medium preferably exhibits a bend coefficient I e ₃₃ And-0.2 pC/m or more, preferably 2pC/m or more.

The liquid-crystalline medium preferably exhibits a voltage of 1 to 10V ^-1 Within the range of preferably 1 to 7V ^-1 In the range of more preferably 1 to 5V ^-1 A flexibility-elasticity ratio (K) in the range.

The medium according to the application exhibits high-definition bright spots of up to 60 ℃ and higher, preferably up to 65 ℃ and higher and more preferably up to 70 ℃ and higher.

The medium according to the application exhibits a broad nematic phase at 30℃and higher, preferably 35℃and higher or even 40℃or higher.

The medium according to the application exhibits an N of 20 ℃ or less, preferably 15 ℃ or less and preferably 0 ℃ or less _TB And (3) phase (C).

The media according to the invention exhibit a high stability against crystallization at room temperature of more than 100h, preferably more than 250h or more than 1000 h.

The medium according to the invention exhibits a high stability against crystallization even at Low Temperatures (LTS). Thus, the medium does not crystallize even at temperatures as low as 0 ℃, preferably as low as-10 ℃, more preferably as low as-20 ℃.

In a preferred embodiment, the liquid-crystalline medium comprises:

1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula I. The amount of the compounds of the formula I in the entire liquid-crystalline medium is preferably from 5 to 50% by weight, in particular from 6 to 30% by weight, especially from 7 to 20% by weight,

and

optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula II, preferably selected from the group consisting of those of formula II (-A) ²¹ -A ²² -) and (-A) ²³ -A ²⁴ (-) are identical or mirror images, more preferably compounds of the formula II 'a-5 and/or II' a-6. The amount of compound of formula II, if present, in the liquid crystalline medium is preferably from 0 to 30% by weight of the total mixture, more preferably from 1% to 20% by weight, even more preferably from 2% to 10% by weight,

and/or

Optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula III, preferably symmetrical compounds selected from formulae IIIc-2 and/or IIIc-3 above. The amount of compound of formula III, if present, in the liquid crystalline medium is preferably from 1 to 50% by weight of the total mixture, more preferably from 5% to 30% by weight, even more preferably from 10% to 20% by weight,

And/or

Optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds of formula IV, preferably symmetrical compounds selected from symmetrical formulae IVb and/or asymmetrical IVc, more preferably from IVb-5, IVc-2, IVc-3, IVc-12 and or IVc-15. The amount of compound of formula IV, if present, in the liquid crystalline medium is preferably from 1 to 98% by weight of the total mixture, more preferably from 20 to 98% by weight, even more preferably from 30 to 60% by weight,

and/or

Optionally, 1 to 6, in particular 2 to 5, very preferably 3 or 4 compounds of formula V, preferably selected from the formulae VA-1, VC-2 and/or VC-3 above. The amount of the compound of formula V, if present, in the liquid crystalline medium is preferably from 1 to 70% by weight of the total mixture, more preferably from 10% to 60% by weight, even more preferably from 20% to 50% by weight,

and/or

Optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds from the above formula VI, preferably selected from the group of compounds of the formulae VI-4, VI-5, VI-7 and/or VI-8. The amount of the compound of formula VI, if present, in the liquid crystalline medium is preferably from 1 to 40% by weight of the total mixture, more preferably from 5% to 25% by weight, even more preferably from 10% to 15% by weight,

And/or

Optionally 1 to 10, preferably 1 to 5, more preferably 1 or 3, most preferably 1 or 2 compounds from formula VII above, preferably selected from compounds of formula VII-4, VII-5 and/or VII-8. The amount of compound of formula VII (if present) in the liquid-crystalline medium is preferably from 1 to 35% by weight, in particular from 5 to 25% by weight, very preferably from 10 to 15% by weight,

and/or

Optionally, 1 to 5, in particular 1 to 3, very preferably 1 or 2 chiral dopants, preferably selected from the above formulae VIII and/or IX and/or R-5011 or S-5011, very preferably, the chiral compound is R-5011 or S-5011. The amount of chiral compound(s), if present, in the liquid-crystalline medium is preferably from 1 to 15% by weight, especially from 0.5% to 10% by weight, very preferably from 0.1% to 5% by weight,

and/or

Optionally up to 25, in particular up to 20, very preferably up to 15 different compounds selected from the group of compounds of formula X. The amount of the compound of the formula X in the entire liquid-crystalline medium is preferably from 1% to 50% by weight, in particular from 5% to 30% by weight, very preferably from 10% to 25% by weight,

and/or

Optionally, other additives, such as stabilizers, antioxidants, etc., present in common concentrations. These other ingredients, if present, are present in a total concentration of 0.1 to 10%, preferably 0.1 to 6%, based on the total mixture. The concentration of the individual compounds used is preferably in each case 0.1 to 3%.

In another preferred embodiment, the liquid-crystalline medium according to the invention consists exclusively of compounds selected from the formulae I to X, very preferably the liquid-crystalline medium consists exclusively of compounds selected from the formulae I to IX.

In another preferred embodiment, the liquid-crystalline medium according to the invention consists only of compounds selected from the group consisting of the formulae I to X, wherein none of the compounds contains a CN group. It is well known that cyano-containing materials have problems when active actuation is considered. This is due to reduced VHR (voltage holding ratio) and other reliability related parameters such as image sticking. Another advantage of materials that do not contain cyano groups is that they are generally less toxic and more environmentally friendly. This makes the synthesis and subsequent transport of cyano-free materials more attractive than cyano-containing materials.

The compounds forming the liquid-crystalline medium according to the invention are mixed in a conventional manner. In general, the desired amount of the compound used in a smaller amount is dissolved in the compound used in a larger amount. Completion of the dissolution process is particularly readily observed at temperatures above the clearing point of the compound used at higher concentrations. However, the medium may also be prepared by other conventional methods, for example using a so-called premix, which may be, for example, a homologous (homologo) or eutectic medium of the compound, or using a so-called multi-bottle system, the component itself being a ready-to-use medium. The invention therefore also relates to a method for producing a liquid-crystalline medium as described above and below.

In particular, the invention relates to a method for preparing a liquid-crystalline medium comprising the step of mixing one or more compounds of formula I with at least one compound selected from the group consisting of compounds of formulae II to X.

The liquid-crystalline media according to the invention can be used in electro-optical devices, for example liquid-crystalline devices, such as STN, TN, AMD-TN, temperature compensation, guest-host, phase-change or surface-stabilized or polymer-stabilized cholesteric texture (SSCT, PSCT) displays, for active and passive optical components such as polarizers, compensators, reflectors, alignment layers, color filters or holographic elements, for adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostic devices, liquid-crystalline pigments, for decorative and security applications, for nonlinear optical devices, optical information stores or as chiral dopants. Thus, a further aspect of the invention is the use of a liquid-crystalline medium comprising at least one compound of the formula I in an electro-optical device.

Since the media according to the invention are particularly useful for curved electro-hydraulic display applications, such as ULH or USH mode devices.

Accordingly, another object of the present invention is a liquid crystal device, preferably a ferroelectric device, comprising a medium comprising one or more compounds of formula I.

A curved display according to a preferred embodiment of the invention comprises two plane-parallel substrates, preferably glass plates, covered on their inner surfaces with a transparent conductive layer, such as Indium Tin Oxide (ITO), an optional alignment layer and a medium comprising one or more compounds of formula I, and chiral dopants as described above and below.

If an electric field is applied perpendicular to the helical axis to this configuration, the optical axis rotates in the plane of the cell, similar to the director of ferroelectric liquid crystals rotating in a surface-stabilized ferroelectric liquid crystal display.

The field induces a splay-bending structure in the director, which is adjusted by the tilt angle in the optical axis. The rotation angle of the shaft is first approximately proportional and linearly proportional to the electric field strength. The optical effect seen is best when the cell is placed between crossed polarizers with the optical axis in an unpowered state at an angle of 22.5 deg. to the absorption axis of one of the polarizers. This angle of 22.5 ° is also the ideal rotation angle of the electric field, so that by reversing the electric field the optical axis is rotated 45 °, and by properly selecting the axes of the spirals, the preferred direction of the absorption axis of the polarizers and the relative orientation of the direction of the electric field, the optical axis can be switched from parallel to one polarizer to a central angle between the two polarizers. When the total angle of optical axis switching is 45 °, then the optimal contrast is achieved. In this case, the configuration may be used as a switchable quarter wave plate provided that the optical retardation (i.e. the product of the effective birefringence of the liquid crystal and the cell thickness) is selected to be a quarter of a wavelength. Unless explicitly stated otherwise, in this context, the wavelength mentioned is 550nm, for which the sensitivity of the human eye is highest.

A good approximation of the rotation angle (Φ) of the optical axis is given by:

tanΦ＝e P ₀ E/(2πK)

wherein the method comprises the steps of

P ₀ Is the undisturbed pitch of the cholesteric liquid crystal,

the element (e) is the bending electric coefficient ₁₁ ) Bending electric number (e) ₃₃ ) Average value [ g=1/2 (e) ₁₁ +e ₃₃ )]，

E is the electric field strength, an

K is the splay elastic constant (K) ₁₁ ) Flexural spring constant (k) ₃₃ ) Average value [ k=1/2 (K) ₁₁ +k ₃₃ )]

And wherein

e/K is referred to as the flex-to-elastic ratio.

This rotation angle is half the switching angle in the curved electrical switching element.

A good approximation of the response time (τ) of this photoelectric effect is given by

τ＝[P ₀ /(2π)] ² ·γ/K

Wherein the method comprises the steps of

Gamma is the effective viscosity coefficient associated with the twist of the helix.

The flexoelectric effect is characterized by a fast response time (T at 35 ℃ C.) typically in the range of 1ms to 10ms _on +T _off ) Preferably<5ms, and even more preferably<3ms. It is further characterized by excellent gray scale capability.

There is a critical field (E _c ) Which can be obtained from the following equation

E _c ＝(π ² /P ₀ )·[k ₂₂ /(ε _0· Δε)] ^1/2

Wherein the method comprises the steps of

k ₂₂ Is the torsional spring constant of the spring,

ε ₀ is the permittivity of vacuum, and

delta epsilon is the dielectric anisotropy of the liquid crystal.

The inventive medium according to the invention can be oriented with its cholesteric phase in different orientations by methods known to the expert, for example surface treatments or electric fields. For example, it may be oriented in a planar (gurlet) state, a focal conic state, or a homeotropic state.

The term "in-plane alignment or orientation" of the liquid crystal or mesogenic material in the display cell or on the substrate means that the mesogenic groups in the liquid crystal or mesogenic material, respectively, are oriented substantially parallel to the plane of the cell or substrate.

The term "homeotropic alignment or orientation" of liquid crystal or mesogenic material in a display cell or on a substrate means that the mesogenic groups in the liquid crystal or mesogenic material, respectively, are oriented substantially perpendicular to the plane of the cell or substrate.

The switching between the different orientation states according to the preferred embodiment of the invention is exemplarily set forth in detail below.

According to this preferred embodiment, the sample is placed in a cassette comprising two planar parallel glass plates coated with an electrode layer (e.g. an ITO layer) and aligned in its cholesteric phase to a planar state, with the axis of the cholesteric helix oriented perpendicular to the cassette wall. This state is also referred to as the gurlet state, and the texture of the sample that can be observed, for example, in a polarizing microscope is referred to as the gurlet texture. The faceting may be achieved, for example, by surface treating the walls of the cartridge, for example, by rubbing and/or coating with an alignment layer such as polyimide.

A gurlet state with high alignment quality and only a few defects can be further achieved by heating the sample to an isotropic phase, followed by cooling to a chiral nematic phase at a temperature close to the chiral nematic-isotropic phase transition, and by slightly pressing the flow alignment of the cell.

In the planar state, the sample shows selective reflection of incident light, wherein the central wavelength of the reflection depends on the helical pitch and the average refractive index of the material.

When an electric field is applied to the electrodes, e.g. at a frequency of 10Hz to 1kHz and an amplitude of at most 12V _rms On an electric field of/. Mu.m, the sample switches to a homeotropic state in which the helices are unwound and the molecules are oriented parallel to the field, i.e. perpendicular to the plane of the electrodes. In the homeotropic state, the sample is transmissive when viewed in vertical sunlight (normal day) and appears black when disposed between orthogonal polarizers.

After reducing or removing the electric field in the homeotropic state, the sample adopts a focal conic texture in which the molecules exhibit a helically twisted structure and the helical axis is oriented perpendicular to the field, i.e. parallel to the plane of the electrodes. The focal conic state can also be achieved by applying only a weak electric field to the sample in its planar state. In the focal conic state, the sample is scattered when viewed in perpendicular sunlight and appears bright between the orthogonal polarizers.

Samples of the medium according to the invention in different orientation states exhibit different light transmission. Therefore, each alignment state and alignment quality thereof can be controlled by measuring light transmittance of a sample depending on the intensity of an applied electric field. Thereby, the electric field strength required for achieving a specific orientation state and transitions between these different states can also be determined.

In a sample of the medium according to the invention, the focal conic state described above consists of a number of disordered birefringent domains. By applying an electric field higher than the field used to nucleate the focal conic texture, preferably accompanied by additional shearing of the cell, a uniformly aligned texture is achieved, wherein the helical axis is parallel to the plane of the electrode in large well aligned areas. This texture is also known as the uniform lying spiral (ULH) texture, according to the literature on the current state of the art for chiral nematic materials, such as p.rudquist et al, liq.cryst.23 (4), 503 (1997). This texture is required to characterize the flexural electrical properties of the compounds of the present invention.

Starting from ULH texture, the media of the present invention can be subjected to flexoelectric switching by application of an electric field. This causes the optical axis of the material to rotate in the plane of the box substrate, which causes a change in transmittance when the material is placed between the crossed polarizers. The bending switching of the material according to the invention is described in further detail in the introduction above and in the examples.

It is also possible to start with a focal conic texture, obtaining ULH texture by applying an electric field with a high frequency of e.g. 10kHz to the sample while slowly cooling from the isotropic phase to the cholesteric phase and shearing the cell. The field frequency may be different for different compounds.

In addition to use in curved electrical devices, the media according to the application are also suitable for other types of displays and other optical and electro-optical applications, such as optical compensation or polarizing films, color filters, reflective cholesteric phases, optical rotation capabilities (optical rotatory power) and optical information stores.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present application to its fullest extent. Accordingly, the following examples should be construed as merely illustrative and not a limitation of the remainder of the present disclosure in any way whatsoever.

As used herein, the plural of terms herein should be understood to include the singular and vice versa, unless the context clearly indicates otherwise.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words (e.g., "comprise" and "include") mean "including but not limited to" and are not intended (and do not) to exclude other components.

Throughout the present application, it will be understood that the bond angle at the C atom bonded to three adjacent atoms (e.g. in a c=c or c=o double bond or e.g. in a benzene ring) is 120 °, and the bond angle at the C atom bonded to two adjacent atoms (e.g. in c≡c or in a c≡n triple bond or in an allyl position c=c) is 180 °, unless these angles are otherwise limited, for example as part of a small ring such as a 3-, 4-, or 5-atom ring, in some cases these angles are not accurately represented in some structural formulas.

It will be appreciated that variations may be made to the foregoing embodiments of the application while still falling within the scope of the application. Each feature disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

All of the features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. In particular, the preferred features of the application are applicable to all aspects of the application and may be used in any combination. Also, features described in non-essential combinations may be used separately (not in combination).

The parameter ranges indicated in the present application all include limits that include the maximum allowable error as known to those skilled in the art. The different upper and lower limits for each property range are combined with each other to yield other preferred ranges.

The total concentration of all compounds in the medium according to the application is 100%. All concentrations are given in% w/w unless explicitly stated otherwise.

In the foregoing and following examples, all temperatures are set forth in degrees celsius without modification and all parts and percentages are by weight unless otherwise indicated.

It is obvious to the person skilled in the art that the liquid-crystalline medium may also comprise compounds, for example H, N, O, cl, F, which are replaced by the corresponding isotopes.

The following abbreviations are used to illustrate the liquid crystalline phase behaviour of the compounds: t (T) _N,I Clear spot; k=crystalline; n=nematic; n (N) _TB =second-column type; s or Sm = smectic; ch = cholesteric; i = isotropic; tg = glass transition. The numbers between the symbols represent the phase transition temperatures in degrees celsius.

In the present application and in particular in the following examples, the structure of the liquid crystal compound is indicated by abbreviations also referred to as "abbreviations". Abbreviations can be directly converted into corresponding structures according to the following three tables a to C.

All radicals C _n H _2n+1 、C _m H _2m+1 And C _I H _2I+1 Preferably straight-chain alkyl having n, m and I C atoms, all radicals C _n H _2n 、C _m H _2m And C _I H _2I Preferably respectively (CH) ₂ ) _n 、(CH ₂ ) _m And (CH) ₂ ) _I And-ch=ch-is preferably trans-or E-vinylidene. Preferably, n, m and I represent integers between 1 and 12.

Table a lists the symbols for the ring elements, table B lists the symbols for the linking groups, and table C lists the symbols for the left hand and right hand end groups of the molecules.

Table a: ring element

Table B: linking groups

Table C: end group

Where n and m are each integers and three points "." indicates the space for the other symbols of this table.

Examples

Test cartridge and method

Typically, 3 μm thick boxes with antiparallel rubbed PI alignment layers on their mutually opposite substrates are filled on a heating plate at a temperature at which the bent electrical mixture is in the isotropic phase.

After the box has been filled, the phase transition (including clearing point and crystallization behavior) is determined using Differential Scanning Calorimetry (DSC) and verified by optical inspection. For optical phase transition measurements, the temperature of the cassette was controlled using a Mettler FP90 hotplate controller connected to a FP82 hotplate. The temperature was raised from ambient temperature at a rate of 5 degrees celsius/min until the onset of the isotropic phase was observed. Texture changes were observed via an orthogonal polarizer using an Olympus BX51 microscope and the respective temperatures were recorded.

A cable (wire) was then attached to the ITO electrode of the cartridge using indium metal. The cassette was fixed in a Linkam THMS600 hotplate connected to a Linkam TMS93 hotplate controller. The heat block was fixed in the turntable of an Olympus BX51 microscope.

The cell is heated until the liquid crystal is completely isotropic. The cell is then cooled under an applied electric field until the sample is fully nematic. The drive waveform is supplied by a Tektronix AFG3021B arbitrary function generator, and is sent via a Newtons4th LPA400 power amplifier, and then applied to the box. The cartridge response was monitored with a Thorlabs PDA55 photodiode. Both the input waveform and the optical response were measured using a Tektronix TDS 2024B digital oscilloscope.

Unless explicitly stated otherwise, to measure the flexural electrical response of a material, the change in the tilt dimension of the optical axis was measured as a function of the voltage rising at a temperature of 35 ℃. This is achieved by using the following equation:

wherein the method comprises the steps ofFor the tilt angle of the optical axis from the initial position (i.e. when e=0), E is the applied field, K is the elastic constant (K ₁ And K ₃ Average value of (d) and e are the bending modulus (where e=e) ₁ +e ₃ ). The applied field was monitored using an HP 34401A multimeter. The tilt angle was measured using the foregoing microscope and oscilloscope. Undisturbed cholesteric pitch P measurement using an Ocean Optics USB4000 spectrometer attached to a computer ₀ . The selective reflection band is obtained and the pitch is determined from the spectral data.

The media shown in the examples below are well suited for ULH displays. For this purpose, the chiral dopant(s) used must be applied in an appropriate concentration to achieve a typical cholesteric pitch of 350 to 275 nm.

Examples of mixtures

Host mixture H-1

The following mixture H1 was prepared

Compounds of formula (I)	% amount-w/w
		N-PP-ZI-9-Z-GP-F	9.52
F-PGI-ZI-7-Z-PP-N	9.52
		F-PGI-ZI-9-Z-PU-N	6.60
F-PGI-ZI-7-Z-PUU-N	10.25
		N-UIUI-9-UU-N	5.86
N-GIGI-9-GG-N	2.92
		N-PGI-ZI-9-Z-GU-F	8.78
N-GI-ZI-9-Z-G-N	7.33
		F-PGI-ZI-9-Z-G-N	3.32
N-PP-ZI-9-Z-G-N	3.32
		F-PGI-ZI-9-Z-P-N	3.32
F-PGI-ZI-9-PUU-N	12.46
		CY-3-O2	2.33
CCY-3-O1	1.17
		CCY-3-O2	1.17
CPY-2-O2	1.46
		CPY-3-O2	1.46
CLY-3-O2	1.17
		Y-4O-O4	1.75
CPTP-3-OD	1.17
		CZY-3-O2	1.46
CZY-5-O2	1.46
		R-5011	2.20

Experiment 1

C.1.1 mixture example M-1

15% w/w of compound 3-LPP-7-GG-F was added to 85% w/w of host mixture H-1.

The resulting mixture was homogenized and filled into a test cartridge as described above. Performing a handover performance, T _NI (clear point), e/K (flexural spring constant) and N _TB The measurements (transition temperature to the second nematic phase or nematic twist bend phase) are summarized in the table below.

Composition and method for producing the same	M-1
		T _on +T _off (at 35 ℃ C.)	4.07ms
e/K (at 35 ℃ C.)	3.02V ^-1
		T _NI	76℃
N _TB	10℃

Experiment 2

C.2.1 mixture example M-2

15% w/w of the compound 5-LP-9-Z-GP-N was added to 85% w/w of the host mixture H-1.

The resulting mixture was homogenized and filled into a test cartridge as described above. Performing a process with respect to switching performance, clearing point, flexural elastic constant and N _TB The measurement of the transition temperature and the results are summarized in the following table.

Composition and method for producing the same	M-2
		T _on +T _off (at 35 ℃ C.)	3.76ms
e/K (at 35 ℃ C.)	3.12V ^-1
		T _NI	75.2℃
N _TB	9.5℃

Experiment 3

C.3.1 mixture example M-3

15% w/w of the compound 5-LP-9-Z-PGG-F was added to 85% w/w of the host mixture H-1.

The resulting mixture was homogenized and filled into a test cartridge as described above. Performing a process with respect to switching performance, clearing point, flexural elastic constant and N _TB The measurement of the transition temperature, the results are summarized in the table below under c.3.3.

C.3.2 comparative mixture example CM-3

15% w/w of compound F-GIGIGI-9-Z-PGG-F was added to 85% w/w of host mixture H-1.

The resulting mixture was homogenized and filled into a test cartridge as described above. Performing a process with respect to switching performance, clearing point, flexural elastic constant and N _TB The measurement of the transition temperature, the results are summarized in the table under c.3.3.

C.3.3 summary

Composition and method for producing the same	M-3	CM-3
			T _on +T _off (at 35 ℃ C.)	3.87ms	4.12ms
e/K (at 35 ℃ C.)	3.12V ^-1	3.05V ^-1
			T _NI	79.9℃	74.6℃
N _TB	8.5℃	-1.0℃

From the measurement results given aboveIt is clear that material M-3 shows an advantage in terms of switching speed compared to material CM-3. At the same time, the phase range is kept at an acceptable level. In addition, it is particularly surprising that T of mixture M-3 _NI T significantly higher than mixture CM-3 _NI 。

Experiment 4

C.4.1 mixture example M-4

15% w/w of the compound 5-LP-7-Z-PGU-F was added to 85% w/w of the host mixture H-1.

The resulting mixture was homogenized and filled into a test cartridge as described above. Performing a process with respect to switching performance, clearing point, flexural elastic constant and N _TB The measurement of the transition temperature, the results are summarized in the table below under c.4.3.

C.4.2 comparative mixture example CM-4

15% w/w of compound F-GIGIGI-7-Z-PGU-F was added to 85% w/w of host mixture H-1.

The resulting mixture was homogenized and filled into a test cartridge as described above. Performing a process with respect to switching performance, clearing point, flexural elastic constant and N _TB The measurement of the transition temperature, the results are summarized in the table under c.4.3.

C.4.3 summary

Composition and method for producing the same	M-4	CM-4
			T _on +T _off (at 35 ℃ C.)	3.35ms	3.87ms
e/K (at 35 ℃ C.)	3.11V ^-1	3.25V ^-1
			T _NI	76.3℃	70.4℃
N _TB	7.0℃	-10.0℃

From the measurements given above, it is clear that material M-4 shows an advantage in terms of switching speed compared to material CM-4. At the same time, the flexural spring constant and the phase range are kept at acceptable levels. In addition, it is particularly surprising that T of mixture M-4 _NI T significantly higher than that of mixture CM-4 _NI 。

Claims

1. Compounds of formula I

Wherein,,

R ¹² represents F, cl, CN, NCS, or straight-chain or branched alkyl which may be unsubstituted, monosubstituted or polysubstituted by halogen or CN, and in which one or more non-adjacent and non-terminal CH' s ₂ The radicals being at each timeCan be represented by-O-, independently of one another-S-, -NH-, -N (CH) ₃ ) -, -CO-, -COO-; -OCO-, -O-CO-O-, -S-CO-, -CO-S-, -ch=ch-, -CH=CF-, -CF=CF-, or-C≡C-being replaced in such a way that the oxygen atoms are not directly connected to each other,

A ¹¹ representation of

A ¹² To A ¹⁴ Each occurrence is independently: 1, 4-phenylene, wherein, in addition, one or more CH groups may be replaced by N; trans-1, 4-cyclohexylene, wherein, in addition, one or two non-adjacent CH ₂ The groups may be replaced by O and/or S; 1, 4-cyclohexylene, naphthalene-2, 6-diyl, decahydro-naphthalene-2, 6-diyl, 1,2,3, 4-tetrahydro-naphthalene-2, 6-diyl, all of which may be unsubstituted, monosubstituted, disubstituted, trisubstituted or tetrasubstituted by F, cl, CN or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl, wherein one or more H atoms may be replaced by F or Cl,

Z ¹¹ z is as follows ¹² Independently at each occurrence a single bond, -COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-OCF ₂ -、-CF ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, optionally substituted with one or more of F, S and/or Si,

p and q are each independently 1,2,3 or 4,

Sp ¹¹ represents- (CH) ₂ ) _n -, and n is an integer of 3, 5, 7, 9, 11 or 13, and

2. The compound according to claim 1, characterized in that the group-A ¹¹ (-Z ¹¹ -A ¹² -) _p -a compound of formula selected from the group consisting of,

Wherein,,

cyc is

Phe is a group selected from the group consisting of 1, 4-phenylene,

z has the formula I ¹¹ And if it occurs twice, at least one selected from the group consisting of-C.ident.C-, -COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-OCF ₂ -or-CF ₂ O-。

3. Compound according to claim 1 or 2, characterized in that the group- (a) ¹³ -Z ¹² -) _q A ¹⁴ -a compound of formula selected from the group consisting of,

wherein,,

CHex is 1, 4-cyclohexylene, phe is 1, 4-phenylene,

z has Z given in part I ¹¹ And if it occurs twice, at least one selected from the group consisting of-C.ident.C-, -COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-OCF ₂ -or-CF ₂ O-。

4. A compound according to claim 1 or 2, characterized in that,

-X ¹¹ -Sp ¹¹ -X ¹² -represents-Sp ¹¹ -、-Sp ¹¹ -O-、-Sp ¹¹ -CO-O-、-Sp ¹¹ -O-CO-、-CO-O-Sp ¹¹ 、-O-CO-Sp ¹¹ 、-O-Sp ¹¹ -、-O-Sp ¹¹ -CO-O-、-O-Sp ¹¹ -O-CO-、-O-CO-Sp ¹¹ -O-、-O-CO-Sp ¹¹ -O-CO-、-CO-O-Sp ¹¹ -O-or-CO-O-Sp ¹¹ -CO-O-, provided that at-X ¹¹ -Sp ¹¹ -X ¹² No two O-atoms are adjacent to each other, no two-ch=ch-groups are adjacent to each other and no two groups selected from-O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-and-ch=ch-are adjacent to each other.

5. Use of compounds of the formula I according to any of claims 1 to 4 for liquid-crystalline media.

6. A liquid-crystalline medium comprising one or more compounds of the formula I according to any one of claims 1 to 4.

7. A liquid-crystalline medium according to claim 6, comprising one or more compounds of the formula II,

R ²¹ -A ²¹ -A ²² -(CH ₂ ) _a -A ²³ -A ²⁴ -R ²² II

wherein,,

R ²¹ and R is ²² H, F, cl, CN, NCS independently of one another, are straight-chain or branched alkyl, which may be unsubstituted, monosubstituted or polysubstituted by halogen or CN, one or more non-adjacent CH' s ₂ The radicals may also be replaced, independently of one another, by-O-, -S-, -NH-, -N (CH) ₃ ) -, -CO-, -COO-; -OCO-, -O-CO-O-, -S-CO-, -CO-S-, -ch=ch-, -CH=CF-, -CF=CF-, or-C≡C-in such a way that the oxygen atoms are not directly connected to each other,

A ²¹ to A ²⁴ Independently at each occurrence, represents aryl-, heteroaryl-, alicyclic-, and heterocyclic groups, and

a represents an integer of 1 to 15.

8. A liquid-crystalline medium according to claim 7, comprising one or more compounds of the formula III,

wherein,,

R ³¹ and R is ³² Independently of one another, of the formula II for R ²¹ The meaning of the terms is given in,

A ³¹ to A ³⁶ Independently of one another, of the formula II for A ²¹ The meaning of the terms is given in,

Z ³¹ and Z ³² Independently of one another at each occurrence, -COO- -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, optionally substituted with one or more of F, S and/or Si,

c represents an integer of 1 to 15, and

b represents an integer of 1 to 15.

9. A liquid-crystalline medium according to claim 7, comprising one or more compounds of the formula IV,

wherein,,

R ⁴¹ and R is ⁴² Independently of one another, of the formula II above for R ²¹ One of the meanings given in the description,

A ⁴¹ to A ⁴⁴ Independently of one another, of the formula II above for A ²¹ One of the meanings given in the description,

Z ⁴¹ and Z ⁴² Independently of one another at each occurrence, -COO- -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, optionally substituted with one or more of F, S and/or Si,

d represents an integer of 1 to 15.

10. A liquid-crystalline medium according to claim 7, comprising one or more compounds of the formula V,

wherein,,

R ⁵¹ and R is ⁵² Independently of one another, of the formula II above for R ²¹ One of the meanings given in the description,

A ⁵¹ to A ⁵³ Independently of one another, of the formula II above for A ²¹ One of the meanings given in the description,

Z ⁵¹ and Z ⁵² Each occurrence is independently-COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, optionally substituted with one or more of F, S and/or Si,

f represents 0 or 1 and is preferably selected from the group consisting of,

e represents an integer of 1 to 15.

11. A liquid-crystalline medium according to claim 7, comprising one or more compounds of the formula VI,

wherein,,

R ⁶¹ and R is ⁶² Independently of one another, of the formula II above for R ²¹ And R is ²² One of the meanings given in the description,

A ⁶¹ to A ⁶⁴ Independently of one another, of the formula II above for A ²¹ One of the meanings given in the description,

Z ⁶¹ represents-O-, -COO-, -OCO- -O-CO-O-, -OCH ₂ -、-CH ₂ O、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, optionally substituted with one or more of F, S and/or Si,

h represents 0 or 1, and

g represents an integer of 1 to 15.

12. A liquid-crystalline medium according to claim 7, comprising one or more compounds of the formula VII,

R ⁷¹ -A ⁷¹ -Z ⁷¹ -A ⁷² -(Z ⁷² -A ⁷³ ) _j -(CH ₂ ) _k -(A ⁷⁴ -Z ⁷³ -) _l -A ⁷⁵ -Z ⁷⁴ -A ⁷⁶ -R ⁷² VII

wherein,,

R ⁷¹ and R is ⁷² Independently of one another, of the formula II above for R ²¹ One of the meanings given in the description,

A ⁷¹ to A ⁷⁶ Independently of one another, of the formula II above for A ²¹ One of the meanings given in the description,

Z ⁷¹ to Z ⁷⁴ Independently of one another, represent-COO-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-OCF ₂ -、-CF ₂ O-、-CH ₂ CH ₂ -、-(CH ₂ ) ₄ -、-CF ₂ CF ₂ -, -CH=CH-, -CF=CF-, -CH=CH-COO-, -OCO-CH=CH-, or-C≡C-, optionally substituted by one or more of F, S and/or Si, or a single bond, provided that Z ⁷¹ To Z ⁷⁴ Is not a single bond,

j represents an integer of 1 to 15, and

i and k represent 0 or 1.

13. The liquid crystal medium of claim 7, comprising one or more chiral dopants.

14. A liquid-crystalline medium according to claim 7, comprising one or more nematic liquid-crystalline compounds selected from the group consisting of the compounds of the formulae X-1 to X-4,

wherein,,

R ^2A represents H, alkyl, alkenyl or alkoxy having 1 to 15 carbon atoms, wherein, in addition, one or more CH of these groups ₂ The radicals may each be, independently of one another, substituted 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, and wherein, in addition, one or more H atoms may be replaced by halogen,

L ¹ and L ² Each independently of the other represents F, cl, CF ₃ Or CHF ₂ ，

p represents 0, 1 or 2,

q represents either 0 or 1 and,

v represents 1 to 6.

15. A process for preparing a liquid-crystalline medium according to any one of claims 6 to 14, comprising the step of mixing one or more compounds of formula I with at least one compound selected from compounds of formulae II to X.

16. Use of a liquid-crystalline medium according to any of claims 6 to 14 for an electro-optical device.

17. An electro-optic device comprising a medium according to any of claims 6-14.

18. An electro-optic device as claimed in claim 17, characterized in that it is a curved electrical device.