Ferroelectric nematic liquid crystal medium

Abstract

The novel LC media exhibit a ferroelectric nematic phase at ambient temperatures. They comprise at least one or more compounds of formula IA having at least five rings, # imgabs0 wherein the variable groups have the meanings indicated in the text and in the claims. These mixtures are useful for electro-optic, electronic, electromechanical and other applications of materials with very high dielectric constant.

Description

[0001] One aspect of the present invention relates to liquid crystal media which exhibit a ferroelectric nematic liquid crystal phase over a relatively large temperature range, preferably at ambient temperature. The medium generally comprises one or more compounds of formula IA as defined below, and optionally compounds of IB and IC. In addition, the present invention relates to liquid crystal devices (e.g. displays), electrical components and electronic components containing the liquid crystal media according to the invention.

[0002] In the past few years, the application field of liquid crystal compounds has been significantly expanded to various types of display devices, electro-optical devices, electronic components, sensors, etc. For this reason, a variety of different structures have been proposed, especially in the field of nematic liquid crystals. Nematic liquid crystal mixtures have been found to be most widely used in flat panel display devices. In particular, they have been used in passive TN or STN matrix displays or systems with TFT active matrices, including the well-known TN, IPS, FFS and VA systems.

[0003] The vast majority of these devices use a nematic liquid crystal phase, including all common LCD televisions, LCD desktop monitors, and mobile LCD devices. Some alternative liquid crystal phases are known, such as the ferroelectric smectic phase or the blue phase. However, for decades, the ferroelectric nematic phase (N f The ferroelectric nematic phase is only a theoretical hypothesis and no suitable liquid crystal material with this property has been found. Until recently, only a few chemical structures have been reported to exhibit ferroelectric nematic behavior.

[0004] Hiroya Nishikawa, Kazuya Shiroshi ta, Hiroki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin-ichi Yamamoto, Koki Sago and Hirotsugu Kikuchi, Adv. Mater. (2017), 29, 1702354 first described that the compound of formula A has ferroelectric nematic behavior at temperatures between about 45°C and 68°C.

[0005]

[0006] In addition, Nerea Sebastián, Luka Cmok, Richard J. Mandle, María Rosario de la Fuente, Irena Olenik,Martin and Alenka Mertelj, Physical Review Letters (2020), 124, 037801 also describe compounds of formula B having similar behavior between about 120°C and 133°C.

[0007]

[0008] Xi Chen et al., PNAS (June 23, 2020), 117(25)14021-14031, the only two f -LC phases were further compared. O.D. Lavrentovich, Proc Nat Acad Sci USA (2020), 117 (26), 14629-14631 emphasizes the new N f -The significance of the emergence of LC phase.

[0009] The publication Li et al., Sci. Adv. 2021, 7 reports extremely high dielectric constant values ​​of these materials and some of their structural variations.

[0010] Atsutaka Manabe, Matthias Bremer, Martin Kraska (2021): Ferroelectric phase at and below room temperature, Liquid Crystals, 48, 1079-1086 (DOI 10.1080 / 02678292.2021.1921867) discloses a new ferroelectric nematic material of formula C, which is described as having a ferroelectric nematic liquid crystal phase (N f -LC phase). Ambient temperature, sometimes also referred to as room temperature, here means a temperature of 20°C in a narrow sense.

[0011]

[0012] Y. Song et al. (Phys. Chem. Chem. Phys., 2022, DOI: 10.1039 / d2cp01110g) describe a material with a ferroelectric nematic phase at high temperature, which has the following structure D:

[0013]

[0014] N for technical applications f- The development of LC phases would obviously benefit from applicability to ambient temperature.Technological devices and electronic applications are often designed to have an operating range above and below ambient temperature, or room temperature, e.g. from 15°C to 25°C, preferably from 0°C to 50°C and more preferably even wider.

[0015] DE19629551 A1 proposes a ferroelectric nematic display, however, it does not disclose any specific material that can satisfy the required ferroelectric nematic properties.

[0016] The use of fluorinated liquid crystal substances is known to those skilled in the art. Various compounds containing two 2,6-difluorinated 1,4-phenylene rings have been described as liquid crystal or mesogenic materials, such as in publication WO 2015 / 101405 A1 and various other publications. The compounds proposed therein have three to four aromatic rings and are characterized as conventional nematic materials without ferroelectric nematic properties.

[0017] The object of the present invention is to find suitable ferroelectric nematic liquid crystal media (N f -LC phase medium). In particular, the compound should have both N f -LC phase or in N f -LC medium. It should also have moderate to high optical anisotropy in order to achieve the same electro-optical switching effect as conventional nematic LC media.

[0018] In view of the extremely wide range of applications of compounds of this type with high dielectric anisotropy (Δε), it is desirable to have available other compounds, preferably with high bright spots and low melting points, while exhibiting a wide and suitable ferroelectric nematic phase temperature range.

[0019] It was therefore a further object of the present invention to find novel stable compounds which are suitable as components of ferroelectric nematic liquid-crystalline media, in particular for displays similar to conventional nematic TN, STN, IPS, FFS and TN-TFT displays.

[0020] A further object is to make the compounds thermally and photochemically stable under the conditions prevailing in the field of application. As mesogens, they should contribute to a broad ferroelectric nematic phase, in particular at low temperatures, at least below room temperature.

[0021] Surprisingly, it has been found that media comprising several selected compounds as described below can achieve a ferroelectric phase in a highly favorable temperature range, and that combinations of specific new compounds with conventional compounds are extremely suitable as N f-Components of LC media. It can be used to obtain LC media with unprecedented properties, including but not limited to liquid crystal media for devices requiring particularly high or even very high dielectric anisotropy, especially for IPS or FFS type displays, as well as for other devices, for electronic applications, capacitors and electromechanical devices using materials with high dielectric constants. The media and compounds used according to the present invention are sufficiently stable and colorless. In particular, they are characterized by very high dielectric constants, and especially very high dielectric anisotropy (Δε), due to which a low threshold voltage is required when used in optical switching elements. The compounds have reasonably good solubility for compounds with comparable properties and can be blended with similar compounds almost without restriction. In addition, the compounds used according to the present invention have high-definition bright spots. These compounds also have relatively low melting points, or can be stably kept below their melting points in the form of supercooled melts. The present invention enables the formation of the desired N f -LC phase.

[0022] A high dielectric constant enables excellent physical performance. A high (relative) dielectric constant is also particularly advantageous for dielectrics in capacitors, as it produces high capacitance at a specific electrode area. In addition, the dielectric has very low conductivity and is superior to conventional high-ε dielectrics due to its fluid properties. r Materials (such as barium titanate).

[0023] Liquid-crystalline media can be used in displays based on the twist cell principle, the guest-host effect, the alignment deformation phase (DAP) or electrically controlled birefringence (ECB) effect, the in-plane switching (IPS) effect or the dynamic scattering effect.

[0024] In one main aspect, the invention therefore relates to a liquid-crystalline medium comprising one or more compounds of the formula IA, preferably in an amount of 15% by weight or more,

[0025]

[0026] in

[0027] X 1A represents -CN, F or -NCS, preferably -CN,

[0028] Z 1A and Z 2A are independently -(CO)-O- or -CF 2 -O- or single bond,

[0029] L 1A is H or CH 3 ,

[0030] L 2Aare independently F or H, preferably H,

[0031] L 3A are independently F or H, preferably F,

[0032] L 4A are independently F or H,

[0033] A 1A express

[0034]

[0035] R 1A are independently alkyl groups having 1 to 12 C atoms, preferably 1 to 8, more preferably 1 to 6, most preferably 1 to 5 C atoms, wherein in addition, one or more CH 2 The groups can be replaced independently of each other in each case by -C≡C-, -CF 2 -O-, -OCF 2 -、-CH=CH-、 -O-, -S-, -(CO)-O- or -O-(CO)- is replaced in such a way that the O / S atoms are not directly connected to each other, and wherein in addition one or more H atoms may be replaced by halogen, or represents H,

[0036] Preferably, R 1A is a halogenated or unsubstituted alkyl radical having 1 to 10 C atoms, wherein in addition, one or more of these radicals CH 2 The group may be replaced by -O- or -CH=CH- in such a way that the O atom is not directly attached,

[0037] n1 is 0 or 1, preferably 1,

[0038] n2 is 0 or 1, and

[0039] n3 is 2 or 3, and if n1+n2+n3 is 2, then A 1A One or more of

[0040]

[0041] This means that if n1 and n2 are both 0, then A 1A At least one of

[0042]

[0043] The liquid-crystalline medium preferably additionally comprises one or more compounds selected from the group consisting of the formulae IB and IC,

[0044]

[0045] R1C -A 3C -Z 2C -A 2C -Z 1C -A 1C -X 1C IC

[0046] in

[0047] X 1B represents -CN, F or -NCS, preferably -CN,

[0048] X 1C Indicates -CN, F, CF 3 、-OCF 3 、-NCS、SF 5 Or O-CF=CF 2 , preferably -CN or -NCS, most preferably CN,

[0049] Z 1B and Z 2B independently of each other represents a single bond, -(CO)-O- or -CF 2 -O-, preferably a single bond,

[0050] Z 1C and Z 2C One of the two groups represents -(CO)-O- or -CF 2 -O- and the other represents a single bond, preferably, Z 1C -(CO)-O- or -CF 2 -O- and Z 2C is a single bond,

[0051] L 1B are independently H or CH 3 , preferably H,

[0052] A 1B express

[0053]

[0054]

[0055] Best

[0056]

[0057] Where L 8B represents alkyl, alkoxy or alkoxyalkyl, each having 1 to 7 C atoms, preferably CH 3 、OCH 3 、OCH 2 CH 3, CH 2 OCH 3 , CH 2 OCH 2 CH 3 , CH 2 CH 2 OCH 3 , CH 2 CH 2 OCH 2 CH 3 or CH 2 CH 2 CH 2 OCH 3 ,

[0058] A 1C Independently express

[0059]

[0060] Best

[0061]

[0062] More preferred

[0063]

[0064] A 2C express

[0065]

[0066] Best

[0067]

[0068] A 3C express

[0069]

[0070] Best

[0071]

[0072] and

[0073] R 1B and R 1C independently of one another represent an alkyl group having 1 to 12 C atoms, preferably 1 to 8, more preferably 1 to 6 and most preferably 1 to 5 C atoms, wherein in addition one or more of these groups CH 2 The groups can be independently of each other in each case -C≡C-, -CF 2 -O-, -OCF 2 -、-CH=CH-、 -O-, -S-, -(CO)-O- or -O-(CO)-, in such a way that the O / S atoms are not directly connected to each other and in which in addition one or more H atoms may be replaced by a halogen; or represents H,

[0074] Preferably R 1A , R 1B and R 1C are independently halogenated or unsubstituted alkyl groups having 1 to 10 C atoms, wherein in addition, one or more of these groups CH 2 The group may be replaced by -O- or -CH=CH- in such a way that the O atom is not directly attached.

[0075] The media contains:

[0076] - preferably 15% by weight or more of a compound of formula IB,

[0077] and / or

[0078] - preferably 15% by weight or more, preferably 20% by weight or more, of one or more compounds of formula IC, preferably selected from formulae IC-1 to IC-3 as described below.

[0079] The percentages are provided with the entire media constituting 100% by weight of the media.

[0080] The radical R in each of the formulae IA, IB and IC and in each of the subformulae thereof 1A , R 1B and R 1C Preferably represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. These alkyl chains are preferably straight chain or 1C In the case of R, it is preferably branched via a single methyl or ethyl substituent, preferably in the 2- or 3-position. 1A , R 1B and R 1C Particularly preferably it represents straight-chain alkyl having 1 to 7 C atoms or unbranched alkenyl having 2 to 8 C atoms, in particular unbranched alkyl having 1 to 5 C atoms.

[0081] Alternative preferred groups R 1A , R 1B and R 1C is selected from cyclopentyl, 2-fluoroethyl, cyclopropylmethyl, cyclopentylmethyl, cyclopentylmethoxy, cyclobutylmethyl, 2-methylcyclopropyl, 2-methylcyclobutyl, 2-methylbutyl, 2-ethylpentyl and 2-alkoxyethoxy.

[0082] Contain branched or substituted terminal groups R1A , R 1B and R 1C The compounds of formulae IA, IB and IC-1 to IC-3 are sometimes of interest due to their good solubility in liquid crystal substrate materials. 1A , R 1B and R 1C Each is preferably a straight chain.

[0083] Group R 1A , R 1B and R 1C Particularly preferably, each is selected from the following parts:

[0084] CH 3

[0085] C 2 H 5

[0086] nC 3 H 7

[0087] nC 4 H 9

[0088] nC 5 H 11

[0089] C 2 H 5 CH(CH 3 )CH 2

[0090] nC 6 H 13

[0091] nC 7 H 15

[0092] nC 3 H 7 CH(C 2 H 5 )CH 2

[0093] nC 8 H 17

[0094] C 3 H 5

[0095] C 3 H 5 CH 2

[0096] cC 4 H 7

[0097] cC 5 H 7

[0098] cC 5 H 9

[0099] cC 5 H 9 CH 2

[0100] CH 2 =CH

[0101] CH 3 CH=CH

[0102] CH 2 =CH(CH 2 ) 2

[0103] CH 3 O

[0104] C 2 H 5 O

[0105] nC 3 H 7 O

[0106] nC 4 H 9 O

[0107] nC 5 H 11 O

[0108] CH 3 AND 2

[0109] C 2 H 5 AND 2

[0110] CH 3 AND 2 CH 2

[0111] C 2 H 5 AND 2 CH 2

[0112] H

[0113] The following end group abbreviations are used:

[0114] C 3 H 5

[0115] C 3 H 5 CH 2

[0116] C 4 H 7

[0117] C 5 H 7

[0118] C 5 H 9

[0119] and

[0120] C 5 H 9 CH 2

[0121] A further embodiment of the invention relates to a ferroelectric nematic liquid-crystalline medium comprising one or more compounds selected from the group consisting of formula IA as defined above, and one or more compounds selected from the group consisting of IB and IC as defined above.

[0122] In a preferred embodiment, the present invention relates to a ferroelectric nematic liquid crystal medium comprising one or more compounds of formulae IC-1 to IC-3 as defined below, preferably in the percentages and preferred formulae as provided throughout the present invention.

[0123]

[0124] wherein the variables are as defined for formula IC, m, n are 0 or 1, wherein m+n=1. Of these, formula IC-1 is preferred. More preferably, the medium according to the invention has at least one compound of formula IC-1.

[0125] In a preferred embodiment, the medium according to the invention preferably comprises one, two, three or more compounds of the formula IA-1

[0126]

[0127] Preferably selected from the formulae IA-1 to IA-3, preferably the formulae IA-1-1, IA-2-1 and IA-3-1:

[0128]

[0129]

[0130]

[0131] The parameters have the meanings given above, and preferably

[0132] L 2A , L 3A , L 4A is H or F,

[0133] Z 1A Indicates -CF 2 -O-.

[0134] For subformula IA-1, L 2A Preferably F and L 3A , L 4A Preferably H.

[0135] For subformula IA-2, L 2A Preferably H and L 3A , L 4A Preferably F. Z 2A Preferably a single bond or -CF 2 O-, more preferably a single bond.

[0136] In a preferred embodiment, the medium according to the invention preferably comprises one, two, three or more compounds of the formula IB-1 and / or IB-2 and / or IB-3, preferably of the formula IB-1,

[0137]

[0138] R 1B denotes an alkyl radical having 1 to 12 C atoms, preferably 1 to 7, more preferably 1 to 6 and most preferably 1 to 5 C atoms, wherein in addition one or more CH 2 The groups can be independently of one another in each case -C≡C-, -CF 2 -O-, -OCF 2 -、-CH=CH-、 -O-, -S-, -CO-O- or -O-CO-, in such a way that the O / S atoms are not directly connected to each other and wherein in addition one or more H atoms may be replaced by a halogen; or represents H,

[0139] Preferably, R 1Bis a halogenated or unsubstituted alkyl radical having 1 to 12 C atoms, wherein in addition, one or more CH 2 The radicals may in each case independently of one another be replaced by -C≡C- or -CH=CH-,

[0140] A 1B express

[0141]

[0142] Best

[0143]

[0144] and

[0145] Z 1B , Z 2B independently represents -(CO)-O- or -CF 2 -O-,

[0146] Preferably, it is selected from the following formulae, ie compounds of formulae IB-1-1 to IB-3-1:

[0147]

[0148] wherein the parameters have the respective meanings given above and in particular, in formulae IB-1-1 to IB-1-3,

[0149] Z 1B Preferably represents -CF 2 -O-,

[0150] And in particular, in formulas IB-2-1 and IB-2-2,

[0151] Z 2B Preferably represents -CF 2 -O-,

[0152] And in particular, in formula IB-2-3,

[0153] Z 2B Preferably it represents -C(O)O-.

[0154] In a preferred embodiment, the medium according to the invention preferably comprises one, two, three or more compounds selected from the group consisting of formulae IC-1-1 to IC-3-6:

[0155]

[0156]

[0157] Among them A 1C As defined above,

[0158] Preferably, it is selected from the following compounds of formula IC-1-1-1 to IC-3-5-2, preferably selected from the compounds of formula IC-1-1-1, IC-1-1-2, IC-1-1-3, IC-1-1-4, IC-3-1-1 and IC-3-2-1:

[0159]

[0160]

[0161]

[0162] wherein the parameters have the respective meanings given above, and preferably L 1C Indicates H,

[0163] Z 1C Indicates -CF 2 -O- or -(CO)-O-, and

[0164] X 1C It represents -CN or -SCN, preferably -CN.

[0165] Particularly preferred compounds of the formulae IC-1-1 to IC-1-4 used in the medium are compounds of the following formulae:

[0166]

[0167] Wherein each parameter is as defined above, preferably L 1C For H.

[0168] In addition to the compounds of the formulae IA, IB and IC-1 / IC-2 / IC-3, the medium according to the invention optionally, preferably necessarily, comprises one, two, three or more compounds selected from the group consisting of the formulae ID-1 to ID-4

[0169]

[0170]

[0171] X D Indicates CN, F, CF 3 、-OCF 3 、NCS、SF 5 Or O-CF=CF 2 , preferably -CN, F, -CF 3 、-OCF 3 , -Cl or -NCS, most preferably F or CN,

[0172] L 1D , L 2D , L3D , L 4D , L 5D , L 6D and L 7D independently represent F, H, alkyl, alkoxy or alkoxyalkyl, each having 1 to 7 C atoms, preferably H, F, CH 3 、OCH 3 、OCH 2 CH 3 , CH 2 OCH 3 , CH 2 OCH 2 CH 3 , CH 2 CH 2 OCH 3 , CH 2 CH 2 OCH 2 CH 3 or CH 2 CH 2 CH 2 OCH 3 ,

[0173] Z 1D and Z 2D represents -(CO)-O-, -CF- 2 -O-, a single bond, and preferably both are -(CO)-O-,

[0174] R 1D denotes an alkyl radical having 1 to 12 C atoms, preferably 1 to 7, more preferably 1 to 6 and most preferably 1 to 5 C atoms, wherein in addition one or more CH 2 The groups can be independently of one another in each case -C≡C-, -CF 2 -O-, -OCF 2 -、-CH=CH-、 -O-, -S-, -(CO)-O- or -O-(CO)-, in such a way that the O / S atoms are not directly connected to each other and in which in addition one or more H atoms may be replaced by a halogen; or represents H,

[0175] Preferably, R 1D is a halogenated or unsubstituted alkyl radical having 1 to 12 C atoms, wherein in addition, one or more CH 2 The radicals may in each case independently of one another be replaced by -C≡C- or -CH=CH-,

[0176] R 2Drepresents alkyl, alkoxy or alkoxyalkyl, each having 1 to 7 C atoms, preferably CH 3 、OCH 3 、OCH 2 CH 3 , CH 2 OCH 3 , CH 2 OCH 2 CH 3 , CH 2 CH 2 OCH 3 , CH 2 CH 2 OCH 2 CH 3 or CH 2 CH 2 CH 2 OCH 3 ,

[0177] A 1D Indicates a single key,

[0178]

[0179] Preferred single bonds,

[0180]

[0181] in

[0182] L 8D represents alkyl, alkoxy or alkoxyalkyl, each having 1 to 7 C atoms, preferably CH 3 、OCH 3 、OCH 2 CH 3 , CH 2 OCH 3 , CH 2 OCH 2 CH 3 , CH 2 CH 2 OCH 3 , CH 2 CH 2 OCH 2 CH 3 or CH 2 CH 2 CH 2 OCH 3 ,

[0183] Preferably, it comprises one or more of formulas ID-1-1 to ID-3-1:

[0184]

[0185]

[0186] The variable group R 1D and L 8D As defined above.

[0187] The medium optionally further comprises one or more compounds selected from the group consisting of:

[0188] The compounds of formulae IA, IB, IC and ID represent "Group 1" of compounds. In a preferred embodiment of the invention, the medium comprises up to 100% of one or more compounds, preferably three, four, five, six or more compounds selected from Group 1. In this embodiment, the medium preferably consists predominantly of these compounds, more preferably, it consists essentially of these compounds, and most preferably, it consists almost entirely of these compounds.

[0189] For the present invention, with regard to the description of the ingredients of the compositions, the following definitions apply, unless otherwise indicated in each case:

[0190] - "comprising": the concentration of the ingredient in question in the composition is preferably 5% or more, particularly preferably 10% or more, very particularly preferably 20% or more,

[0191] - "consists essentially of": the concentration of the ingredient in question in the composition is preferably 50% or more, particularly preferably 55% or more and very particularly preferably 60% or more,

[0192] - "essentially consists of": the concentration of the ingredient in question in the composition is preferably 80% or more, particularly preferably 90% or more and very particularly preferably 95% or more, and

[0193] - "consists almost entirely of": the concentration of the ingredient in question in the composition is preferably 98% or more, particularly preferably 99% or more and very particularly preferably 100.0%.

[0194] Preferably, the medium according to the present application satisfies one or more of the following conditions. They preferably include:

[0195] 15 wt% or more of the compound of formula IA, more preferably 20 wt%, more preferably 25 wt%, 30 wt%, 35 wt%, 45 wt% or 50 wt% or more of the compound of formula IA,

[0196] - 5 wt% or more of the compound of formula IB, more preferably 10 wt% or more, more preferably 20 wt% or more and most preferably 30 wt% or more of the compound of formula IB,

[0197] - a total of 40 wt.% or more of compounds selected from the group consisting of formulae IA and IB, more preferably 60 wt.%, more preferably 75 wt.% or more and most preferably 90 wt.% or more of compounds selected from the group consisting of formulae IA and IB, i.e. the sum of the compounds of formulae IA and IB is preferably at least one of the above values,

[0198] 5 wt. % or more, preferably 10 wt. % or more, more preferably 15 wt. % or more, more preferably 20 wt. % or more and most preferably 25 wt. % or more of a compound selected from the group consisting of formula IC-1, IC-2 and IC-3,

[0199] - a total of 45% by weight or more of compounds selected from the group consisting of formulae IA, IB and IC, more preferably 70% by weight, more preferably 85% by weight or more and most preferably 90% by weight or more of compounds selected from the group consisting of formulae IA, IB and IC, i.e. the sum of the compounds of these formulae,

[0200] - optionally 2 wt% or more of a compound of formula ID (ID-1, ID-2, ID-3, ID-4), more preferably 5 wt%, more preferably 10 wt% or more and most preferably 15 wt% or more of a compound of formula ID,

[0201] - one, two, three or more compounds of formula IA-1-1 or IA-1-2, preferably a compound of formula AUUQGU-nN, AUUQGG-nN, PGGUQU-nF, most preferably a compound selected from the group of compounds AUUQGU-2-N, AUUQGU-3-N, AUUQGU-4-N, AUUQGU-5-N and AUUQGU-6-N,

[0202] - one, two, three or more, preferably three or more compounds of formula IB-1, preferably a compound of formula GUUQU-nN and / or DUUQU-nN, most preferably a compound selected from the group of compounds GUUQU-2-N, GUUQU-3-N, GUUQU-4-N, GUUQU-5-N, GUUQU-6-N, GUUQU-7-N, DUUQU-2-N, DUUQU-3-N, DUUQU-4-N, DUUQU-5-N and DUUQU-6-N,

[0203] - one, two, three or more compounds of formula IB-1-3, preferably a compound of formula GUUQU-nN, more preferably a compound selected from the group of compounds GUUQU-3-N, GUUQU-4-N and GUUQU-5-N,

[0204] - one, two, three or more compounds of formula IB-3-1, preferably a compound of formula DUUQU-nF, more preferably a compound selected from the group of compounds DUUQU-3-F, DUUQU-4-F and DUUQU-5-F,

[0205] - one, two, three or more compounds of formula IC-1-1, preferably a compound of formula MUZU-nN or MUQU-nN, more preferably a compound selected from the group of compounds MUZU-2-N, MUZU-3-N, MUZU-4-N and MUZU-5-N,

[0206] one, two, three or more compounds of formula IC-3, preferably compounds selected from IC-3-2 and IC-3-3, more preferably compounds selected from formula MUU-nN or UMU-nN, more preferably compounds selected from the group of compounds MUU-3-N, MUU-4-N, MUU-5-F, UMU-3-N, UMU-4-N and UMU-5-N,

[0207] - one, two, three or more compounds of formula IC-1-1, preferably a compound selected from the group consisting of formula GUZU-nN or GUQU-nN, more preferably a compound selected from the group consisting of compounds GUZU-3-N, GUZU-4-N, GUZU-5-F, GUQU-3-N, GUQU-4-N and GUQU-5-N,

[0208] and / or

[0209] - one, two, three or more compounds of the group of formula IC-1-1-3 and IC-1-1-4, preferably a compound of formula UUZU-nN and / or UUQU-nN, most preferably a compound selected from the group of compounds UUZU-2-N, UUZU-3-N, UUZU-4-N, UUZU-5-N, UUQU-2-N, UUQU-3-N and UUQU-4-N,

[0210] wherein n is 1, 2, 3, 4, 5, 6 or 7.

[0211] In another preferred embodiment of the present invention, the compounds of formula IA, IB and IC-1 / IC-2 / IC-3 are compounds of the first group, i.e., compounds of Group 1. In this embodiment, the compound concentration of this Group 1 compound is preferably in the range of 70% or more, preferably 80% or more, more preferably 90% or more to 100% or less.

[0212] The medium according to the invention optionally contains one or more compounds selected from the group of compounds of formulae II and III (group 2), preferably in a concentration of greater than 0% to 40% or less,

[0213]

[0214] in

[0215] R 2 represents an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy group having 1 to 7 C atoms; an alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl group having 2 to 7 C atoms, and is preferably an alkyl or alkenyl group,

[0216]

[0217] At each occurrence, independently of each other, it means

[0218]

[0219] Best

[0220]

[0221] L 21 and L 22 represents H or F, preferably L 21 Indicates F,

[0222] L 32 and L 33 Indicates H, F or CH 3 , preferably H,

[0223] X 2 represents halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms, or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, preferably F, Cl, -OCF 3 、-O-CH 2 CF 3 、-O-CH=CH 2 、-O-CH=CF 2 or -CF 3 , most preferably F, Cl, -O-CH=CF 2 or -OCF3 ,

[0224] m represents 0, 1, 2 or 3, preferably 1 or 2 and particularly preferably 2,

[0225] R 3 represents an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy radical having 1 to 7 C atoms; an alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl radical having 2 to 7 C atoms, and is preferably an n-alkyl, cyclopropyl, cyclopentyl or alkenyl radical,

[0226]

[0227] At each occurrence, independently of each other

[0228]

[0229]

[0230] Best

[0231]

[0232] L 31 and L 32 independently of each other represent H or F, preferably L 31 Indicates F,

[0233] X 3 represents halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms, or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, F, Cl, -OCF 3 、-OCHF 2 、-O-CH 2 CF 3 、-O-CH=CF 2 、-O-CH=CH 2 or -CF 3 , most preferably F, Cl, -O-CH=CF 2 、-OCHF 2 or -OCF 3 ,

[0234] Z 3 Indicates -CH 2 CH 2 -、-CF 2 CF 2 -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH 2 O- or a single bond, preferably -CH 2 CH 2-, -COO-, trans-CH=CH- or a single bond and very preferably -(CO)-O-, trans-CH=CH- or a single bond, and

[0235] n is 0, 1, 2 or 3, preferably 1, 2 or 3 and particularly preferably 1,

[0236] wherein the respective rings and preferably the phenylene rings are optionally each substituted by one or two alkyl groups, preferably by methyl and / or ethyl groups, preferably by one methyl group, and wherein compounds of formulae IA, IB, IC and ID are not included in the compounds of formula II,

[0237] Optionally, alternatively or additionally, one or more compounds selected from the group of compounds of formula IV and V (Group 3), preferably in a concentration of greater than 0% to 15%,

[0238]

[0239] in

[0240] R 41 and R 42 Independently of each other, they have the above R 2 The indicated meaning, preferably R 41 represents an alkyl group and R 42 represents an alkyl group or an alkoxy group, or R 41 represents an alkenyl group and R 42 represents an alkyl group,

[0241]

[0242] Independently of each other, and if

[0243] Appears twice,

[0244] These also represent independently of each other

[0245]

[0246]

[0247] Best

[0248] One or more of

[0249]

[0250] Z 41 and Z 42 independently represent the following groups, and if Z 41 If they appear twice, these groups also represent the following groups independently of each other: -CH2 CH 2 -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH 2 O-、-CF 2 -O-, -C≡C- or a single bond, preferably one or more of which represent a single bond, and

[0251] p represents 0, 1 or 2, preferably 0 or 1, and

[0252] R 51 and R 52 Independently of each other, they have 41 and R 42 one of the meanings given, and preferably denotes alkyl having 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C atoms; alkoxy having 1 to 7 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 C atoms; alkoxyalkyl, alkenyl or alkenyloxy, preferably alkenyloxy, having 2 to 7 C atoms, preferably 2 to 4 C atoms,

[0253] to

[0254] If present, they represent each independently of the other

[0255]

[0256] Preferably

[0257]

[0258] Preferably

[0259] express

[0260] And if there is

[0261] Preferably means

[0262] Z 51 To Z 53 Each independently represents -CH 2 -CH 2 -、-CH 2 -O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH 2 -CH 2 -、-CH 2 -O- or a single bond, and particularly preferably a single bond,

[0263] i and j each independently represent 0 or 1,

[0264] (i+j) preferably represents 0, 1 or 2, more preferably 0 or 1 and most preferably 1,

[0265] wherein the individual rings and preferably the phenylene rings are optionally each substituted by one or two alkyl groups, preferably by methyl and / or ethyl groups, preferably by one methyl group, and

[0266] Optionally, alternatively or additionally, one or more compounds selected from Group 4, i.e. the group of compounds of formulae I and VI to IX, preferably two, three or more compounds, preferably in a concentration of greater than 0% to 20%,

[0267]

[0268]

[0269] in

[0270] express

[0271]

[0272]

[0273] express

[0274]

[0275] Preferably

[0276]

[0277] n represents 0 or 1,

[0278] R 11 and R 12 represents, independently of one another, an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy radical preferably having 1 to 7 C atoms, in which one CH 2 The radical may be substituted by 1,2-cyclopropyl, 1,3-cyclopentyl or 1,3-cyclopentenylene; alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, and is preferably alkyl, alkoxy, alkenyl or alkenyloxy, most preferably alkyl, alkoxy or alkenyloxy,

[0279] R 61represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, most preferably a propyl group or a pentyl group; an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably a group having 2 to 5 C atoms; an unsubstituted alkoxy group having 1 to 6 C atoms; or an unsubstituted alkenyloxy group having 2 to 6 C atoms,

[0280] R 62 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyloxy group having 2 to 6 C atoms, and

[0281] l means 0 or 1,

[0282] R 71 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, most preferably a propyl group or a pentyl group; or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably a group having 2 to 5 C atoms,

[0283] R 72 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms; an unsubstituted alkoxy group having 1 to 6 C atoms, preferably having 1, 2, 3 or 4 C atoms; or an unsubstituted alkenyloxy group having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms, and

[0284] express

[0285]

[0286] R 81 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, most preferably a propyl group or a pentyl group; or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably a group having 2 to 5 C atoms,

[0287] R 82 represents an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms; an unsubstituted alkoxy radical having 1 to 6 C atoms, preferably having 1, 2, 3 or 4 C atoms; or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms,

[0288] express

[0289]

[0290] Preferably

[0291]

[0292] More preferably

[0293]

[0294] Z 8 Indicates -(CO)-O-, -CH 2 -O-, -CF 2 -O- or -CH 2 -CH 2 -, preferably -(CO)-O- or -CH 2 -O-, and

[0295] o means 0 or 1,

[0296] R 91 and R 92 Independently of each other, they have the above 72 The meaning given,

[0297] R 91 preferably denotes an alkyl radical having 2 to 5 C atoms, preferably having 3 to 5 C atoms,

[0298] R 92 preferably represents an alkyl or alkoxy group having 2 to 5 C atoms, more preferably an alkoxy group having 2 to 4 C atoms; or an alkenyloxy group having 2 to 4 C atoms,

[0299] express

[0300] p and q are independently 0 or 1, and

[0301] (p+q) preferably represents 0 or 1, provided that

[0302] express

[0303] Alternatively, preferably p=q=1,

[0304] wherein the individual rings and preferably the phenylene rings are optionally each substituted by one or two alkyl groups, preferably by methyl and / or ethyl groups, preferably by one methyl group,

[0305] Especially the ring

[0306] Alternative Instead,

[0307] and wherein the compound of formula VII is not included in the compound of formula IX, and the compound of formula I is not included in the compounds of formulae VI to IX or the compound of formula IX,

[0308] Optionally, preferably necessarily alternatively or additionally, one or more compounds selected from Group 5, i.e. the group of compounds of formula B, preferably two, three or more compounds, preferably in a concentration of greater than 0% to 20%,

[0309]

[0310] in

[0311] express

[0312]

[0313] In each occurrence, they are expressed independently of each other

[0314]

[0315] Preferably

[0316] Most preferably

[0317] n represents 0, 1 or 2, preferably 1,

[0318] R 1 represents an alkyl group having 1 to 7 C atoms, wherein one or more CH 2 group, preferably a CH 2 The groups can each independently be -C≡C-, -CF 2 -O-, -OCF 2 -, -O-, -(CO)-O-, -O-(C=O)-, cyclopropylene, 1,3-cyclobutylene, 1,3-cyclopentylene, 1,3-cyclopentenylene, preferably substituted by cyclopropylene or 1,3-cyclopentylene, preferably one CH 2 The group may be substituted by 1,2-cyclopropylene, 1,3-cyclopentylene or 1,3-cyclopentenylene; an alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl group having 2 to 7 C atoms, and is preferably an alkyl or alkenyl group in which one -CH 2 - group may be substituted by cyclopropylene, 1,3-cyclobutylene, 1,3-cyclopentylene, 1,3-cyclopentenylene, preferably by cyclopropylene or 1,3-cyclopentenylene, in such a way that the O atoms are not directly connected to each other, and one or more H atoms may be substituted by halogen, and

[0319] X 1 represents F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenyloxy, the latter four groups preferably having 1 to 4 C atoms; more preferably represents F, Cl, CF 3 or OCF 3 ,and

[0320] Wherein the individual rings and preferably the phenylene ring may optionally each be substituted by one or two alkyl groups, preferably by methyl and / or ethyl groups, preferably by one methyl group.

[0321] Preferred are media comprising one or more compounds of group 1 and group 2.

[0322] The corresponding starting materials can generally be prepared easily by the person skilled in the art by synthetic methods known from the literature or are commercially available. The reaction methods and reagents used are known in principle from the literature.

[0323] In the present invention, the 2,5-disubstituted dioxane ring of the formula

[0324]

[0325] Preferably represents a dioxane ring in 2,5-trans configuration, ie the substituents R are preferably all in the equatorial position in a preferred chair conformation. A 2,5-disubstituted tetrahydropyran of the formula

[0326]

[0327] Likewise preferably is intended a tetrahydropyran ring in the 2,5-trans configuration, ie the substituents are preferably all in the equatorial position in a preferably chair conformation.

[0328] The liquid crystal medium according to the present invention has a wide ferroelectric nematic phase temperature range. It exhibits a ferroelectric nematic phase range at 20°C and above and below 20°C (ambient temperature). It covers the range of the most technically concerned from at least 10 to 50°C and significantly beyond to lower and / or higher temperatures. Therefore, it is very suitable for all kinds of domestic or industrial uses, and even has some restrictions outdoors. The medium exhibits a ferroelectric nematic phase at least in a temperature range of 20K (Kelvin) or higher, more preferably in a range of 30K or higher and most preferably in a range of 40K or higher. Preferably, the medium exhibits an interconverting ferroelectric nematic phase, i.e., a ferroelectric nematic phase temperature range that appears when cooled from a higher temperature and heated from a lower temperature. The temperature range of the ferroelectric nematic phase, clearing point, low temperature stability (LTS), (relative) dielectric constant, dielectric anisotropy and optical anisotropy of the compounds containing formula IA, IB and IC-1 / IC-2 / IC-3 are far superior to previous materials of this type from the prior art. Previously only single compound materials were available in limited selection, which had a restricted range of ferroelectric nematic phases.

[0329] In addition, the mixtures according to the invention generally also exhibit a very broad nematic phase range with a clearing point of 65° C. or higher.

[0330] The liquid-crystalline media according to the invention preferably exhibit a ferroelectric nematic phase temperature range of 20 degrees or more, which preferably extends over a range of 40 degrees or more, more preferably 60 degrees or more.

[0331] Preferably, the liquid-crystalline medium according to the present invention exhibits a ferroelectric nematic phase preferably from 10°C to 30°C, more preferably from 10°C to 40°C, more preferably from 10°C to 50°C, more preferably from 0°C to 50°C and most preferably from -10°C to 50°C.

[0332] In another preferred embodiment, the liquid-crystalline media according to the invention exhibit a ferroelectric nematic phase preferably from 10 to 40°C, more preferably from 10 to 50°C, more preferably from 10 to 60°C and most preferably from 10 to 70°C.

[0333] The liquid-crystalline media according to the invention exhibit outstanding dielectric properties.

[0334] Due to the outstanding properties, the medium can play a role in many new technological fields and can be used for electro-optical purposes, for supercapacitors, nonlinear optical components, electric field sensors, memory devices and electromechanical devices including generators (i.e., energy harvesting devices) and actuators. The material can, for example, enable unconventional modes of harvesting energy from vibrational motion.

[0335] Preferably, the ε of the medium according to the invention is rThe value (at 20° C. and 10 Hz) is 700 or more, more preferably 800 or more, more preferably 15,000 or more, even more preferably 30,000 or more and more preferably 35,000 or more.

[0336] These dielectric properties are achieved at temperatures that place the medium in the ferroelectric nematic phase. Dielectric characteristics can exhibit hysteretic behavior, especially at varying temperatures, and in this case the value obtained at a certain temperature can depend on the history of the material, i.e., whether the material has been subjected to heating or cooling.

[0337] This effect enables, among other things, the device to be operated, for example, in a bistable mode and can thus be advantageously used in electro-optical devices, as are known, for example, from ferroelectric smectic devices.

[0338] The liquid-crystalline media according to the invention preferably contain from 2 to 40, particularly preferably from 4 to 20 compounds as further constituents in addition to one or more compounds according to the invention. In particular, these media may contain from 1 to 25 components in addition to one or more compounds according to the invention. These further constituents are preferably selected from ferroelectric nematic or nematic (monotropic or isotropic) substances.

[0339] Prior art ferroelectric materials and similar compounds with high dielectric constants for combination with the materials of the present invention are selected from, for example, the following structures:

[0340]

[0341]

[0342] The medium according to the invention preferably comprises 1% to 100%, more preferably 10% to 100% and especially preferably 50% to 100% of the compounds of the formulae IA and / or IB and / or IC-1 / IC-2 / IC-3 preferably used according to the invention.

[0343] The present invention also relates to a process for preparing a liquid crystal medium as described herein, wherein at least two or more compounds selected from the group consisting of formula IA, optionally one or more compounds of formula IB, IC and any other components or additives are combined and mixed with one another. The resulting mixture is equal to 100% by weight.

[0344] The liquid crystal mixture according to the invention is prepared in a conventional manner per se. In general, the required amount of the component used in a smaller amount is dissolved in the component constituting the main constituent, preferably at elevated temperature. It is also possible to mix the components in an organic solvent, for example a solution in acetone, chloroform or methanol, and after thorough mixing, remove the solvent, for example by distillation. Furthermore, the mixture can be prepared in other conventional ways, for example by using premixes, for example homologous mixtures, or using a so-called "multi-bottle" system.

[0345] The liquid crystal mixture may also contain other additives known to the person skilled in the art and described in the literature. For example, 0 to 15%, preferably 0 to 10%, of pleochroic dyes, chiral dopants, stabilizers or nanoparticles may be added. The individual compounds added are used in a concentration of 0.01 to 6%, preferably 0.1 to 3%. However, the concentration data for the other constituents of the liquid crystal mixture (i.e. the liquid crystal or mesogenic compound) are given here without taking into account the concentrations of these additives.

[0346] The liquid-crystal mixtures according to the invention make it possible to significantly broaden the available parameter latitude.

[0347] The invention also relates to electro-optical devices, preferably displays (especially TFT displays, which have two plane-parallel external plates forming a box together with a frame, integrated non-linear elements on the external plates for switching individual pixels, and ferroelectric nematic liquid crystal material with positive dielectric anisotropy and high resistivity located in the box), containing such media, and the use of these media for electro-optical purposes.

[0348] The expression "alkyl" encompasses unbranched and branched alkyl radicals having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, in particular and preferably the unbranched radicals methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl and n-heptyl, and further, alternatively, the radicals n-butyl, n-pentyl, n-hexyl and n-heptyl substituted by one methyl, ethyl or propyl radical. Radicals having 1 to 5 carbon atoms are generally preferred.

[0349] The expression "alkenyl" encompasses unbranched and branched alkenyl groups having up to 12 carbon atoms, especially unbranched groups. Particularly preferred alkenyl groups are C 2 -C 7 -1E-alkenyl, C 4 -C 7 -3E-alkenyl, C 5 -C 7 -4-Alkenyl, C 6 -C 7 -5-Alkenyl and C 7 -6-alkenyl, especially C 2 -C 7 -1E-alkenyl, C 4 -C 7 -3E-alkenyl and C 5 -C 7-4-alkenyl. Examples of preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and similar groups. Groups with 2 to 5 carbon atoms are generally preferred.

[0350] The expression "halogenated alkyl" preferably encompasses mono- or polyfluorinated and / or chlorinated groups. Perhalogenated groups are included. Particularly preferred are fluorinated alkyl groups, especially CF 3 , CH 2 CF 3 , CH 2 CHF 2 , CHF 2 , CH 2 F. CHFCF 3 and CF 2 CHF 3 The expression "alkenyl halide" and related expressions are to be interpreted accordingly.

[0351] The matrix display according to the present invention, which is constructed by polarizers, electrode substrate plates and surface-treated electrodes, corresponds to the common design of such displays. The term common design is described broadly here and also covers all derivatives and variants of matrix displays, especially matrix display components based on polysilicon TFTs.

[0352] However, a fundamental difference between the displays according to the invention and hitherto conventional displays based on twisted nematic cells lies in the choice of the liquid-crystal parameters of the liquid-crystal layer.

[0353] The following examples illustrate the invention without intending to limit it. A person skilled in the art will be able to discover from the examples working details which are not given in detail in the general description, generalize them according to general expert knowledge and apply them to specific problems.

[0354] In the above and below, percentage data refer to weight percentages. Unless explicitly indicated otherwise, all temperature values ​​indicated in the present application, such as melting points T(C,N), phase transitions T(S,N) from the smectic phase (Sm) to the nematic phase (N) and clearing points T(N,I) or T(N f, I), are indicated in degrees Celsius (°C), and all temperature differences are indicated in different degrees (° or degrees) accordingly. In addition, C = crystalline state, N = nematic phase, Nf = ferroelectric nematic phase, Sm = smectic phase (more particularly SmA, SmB, etc.), Tg = glass transition temperature and I = isotropic phase. The data between these symbols represent the transition temperature. Δn represents optical anisotropy (589nm, 20°C), Δε represents dielectric anisotropy (1kHz, 20°C).

[0355] The physical, physicochemical and electro-optical parameters are determined by generally known methods, such as, in particular, the manual "Merck Liquid Crystals- -Physical Propert ies of Liquid Crys tals -Description of the Measurement Methods", 1998, Merck KGaA, Darmstadt.

[0356] The presence of the ferroelectric nematic phase of the material is determined using differential scanning calorimetry (DSC), identified by observing the texture under a polarizing microscope equipped with a hot stage for controlled cooling or heating, and additionally confirmed by determining the temperature dependence of the dielectric properties. The transition temperature is primarily determined by probing the optical behavior under a polarizing microscope.

[0357] The dielectric anisotropy Δε of the individual substances was determined at 20° C. and 1 kHz. For this purpose, 5 to 10% by weight of the substance under investigation dissolved in the dielectrically positive mixture ZLI-4792 (Merck KGaA) were measured and the measured values ​​were extrapolated to a concentration of 100%. The optical anisotropy Δn was determined at 20° C. and a wavelength of 589.3 nm by linear extrapolation.

[0358] The relative dielectric constant (ε r ) is determined directly by measuring the capacitance of at least one test cell containing the compound and having a cell thickness of 250 μm and in homeotropic and planar orientation, respectively. The temperature is controlled by a Novocontrol Novocool system set to apply a temperature gradient of + / -1 K / min; + / -2 K / min; + / -5 K / min; + / -10 K / min to the sample cell. The capacitance is measured by a Novocontrol alpha-N analyzer at a frequency of 1 kHz or 10 Hz, with typical voltages <50 mV and down to 0.1 mV to ensure below the threshold of the compound under investigation. The measurements are performed with the sample heated and with cooling.

[0359] In this application, unless explicitly indicated otherwise, plural forms of terms refer to both the singular and the plural, and vice versa. According to this description, other combinations of embodiments and variants of the invention also result from the appended claims or from a combination of a plurality of these claims.

[0360] Further combinations of embodiments of the invention and variants of the invention are also disclosed by the claims.

[0361] Without further elaboration, it is believed that one skilled in the art can utilize the foregoing description to the greatest extent possible the present invention. Therefore, the foregoing preferred embodiments should be construed as merely illustrative and not limiting in any way whatsoever the remainder of the invention. The foregoing examples may be similarly and successfully repeated by substituting the generically or specifically described reactants and / or operating conditions of the present invention for the reactants and / or operating conditions used in the foregoing examples.

[0362] From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope of the invention, can make various changes and modifications of the invention to adapt it to various usages and conditions.

[0363] This applies to the medium as a composition with its components, which may be groups of compounds as well as individual compounds, and it applies to the group of compounds with its individual components (i.e. compounds). With regard only to the concentration of the individual compounds relative to the medium as a whole, the term comprises means that the concentration of the compound or compounds in question is preferably 1% or more, particularly preferably 2% or more, very particularly preferably 4% or more.

[0364] For the present invention, "≤" means less than or equal to, preferably less than, and "≥" means greater than or equal to, preferably greater than.

[0365] For the present invention,

[0366] and

[0367] represents trans-1,4-cyclohexylene,

[0368]

[0369] represents a mixture of cis-1,4-cyclohexylene and trans-1,4-cyclohexylene, and

[0370] as well as

[0371] It represents 1,4-phenylene.

[0372] For the purposes of the present invention, the expression "dielectrically positive compound" means a compound with Δε>1.5, the expression "dielectrically neutral compound" means a compound with -1.5≤Δε≤1.5, and the expression "dielectrically negative compound" means a compound with Δε<-1.5. The dielectric anisotropy of the compound is determined here by dissolving 10% of the compound in a liquid-crystalline host and determining the capacitance of the resulting mixture in each case in at least one test cell with a cell thickness of 20 μm and a homeotropic and homogeneous surface alignment at 1 kHz. The measuring voltage is generally between 0.5 V and 1.0 V, but always below the capacitance threshold of the respective liquid-crystalline mixture (material) under investigation.

[0373] The host mixture for dielectrically positive and dielectrically neutral compounds was ZLI-4792 and the host mixture for dielectrically negative compounds was ZLI-2857, both from Merck KGaA, Germany. The values ​​for the individual compounds to be investigated were obtained from the change in the dielectric constant of the host mixture after addition of the compound to be investigated and extrapolated to 100% of the compound used. The compound to be investigated was dissolved in the host mixture in an amount of 10%. If the solubility of the substance was too low to be used for this purpose, the concentration was halved in the steps until the investigation could be carried out at the desired temperature.

[0374] If necessary, the liquid crystal medium according to the present invention may also contain other additives, such as stabilizers in conventional amounts. The amount of these additives used is preferably 0% or more to 10% or less in total, particularly preferably 0.1% or more to 6% or less, based on the amount of the entire mixture. The concentration of each compound used is preferably 0.1% or more to 3% or less. When specifying the concentration and concentration range of the liquid crystal compound in the liquid crystal medium, the concentration of these and similar additives is generally not considered.

[0375] For the purposes of the present invention, all concentrations are indicated as weight percent, unless expressly stated otherwise, and relate to the respective mixture as a whole or to the mixture components (again as a whole), unless expressly stated otherwise. In this context, the term "mixture" describes a liquid-crystalline medium.

[0376] Unless explicitly stated otherwise, the following symbols are used:

[0377] T(N,I) or T(N f ,I)(or clp.) clearing point [℃],

[0378] Dielectric properties at 1kHz and preferably at 20°C or at the respective specified temperatures:

[0379] ε ┴ The dielectric constant perpendicular to the director,

[0380] ε || The dielectric constant parallel to the director,

[0381] Δε dielectric anisotropy and in particular screening data for a single compound.

[0382] Again, in particular with respect to the data obtained from screening individual compounds in the nematic host mixture ZLI-4792:

[0383] n e The extraordinary refractive index measured at 20°C and 589nm,

[0384] n o Ordinary refractive index measured at 20°C and 589nm and

[0385] Δn is the optical anisotropy measured at 20°C and 589 nm.

[0386] The following examples explain the present invention, but do not limit the present invention. However, they show the preferred mixture concept of the compounds and their respective concentrations and their combinations with each other that are preferably adopted to those skilled in the art. In addition, the examples illustrate obtainable properties and property combinations.

[0387] The structural elements are defined by the abbreviations used for each compound:

[0388] Table A: Ring elements

[0389]

[0390]

[0391]

[0392] Table B: Bridge Units

[0393]

[0394]

[0395] Table C: End Groups

[0396]

[0397] Where n and m are each integers, and the three dots “…” are placeholders for other abbreviations in this table.

[0398] Besides the compounds of the formulae IA, IB and IC-1 / IC-2 / IC-3, the mixtures according to the invention preferably comprise one or more of the compounds mentioned below.

[0399] The following abbreviations are used: (n, m, k and l are each independently an integer, preferably 1 to 9, preferably 1 to 7; k and l may also be 0 and are preferably 0 to 4, more preferably 0 or 2 and most preferably 2; n is preferably 1, 2, 3, 4 or 5, in the combination "-nO-", it is preferably 1, 2, 3 or 4, preferably 2 or 4; m is preferably 1, 2, 3, 4 or 5, in the combination "-Om", it is preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-lVm" is preferably "2V1".)

[0400] For the present invention and in the following examples, the structures of the liquid crystal compounds are indicated with the aid of acronyms and the conversion of the chemical formulae is carried out according to Tables A to C above. All groups C n H 2n+1 , C m H 2m+1 and C l H 2l+1 or C n H 2n , C m H 2m and C l H 2l are straight-chain alkyl or alkylene groups, in each case with n, m and 1 C atoms, respectively. Preferably, n, m and 1 are independently 1, 2, 3, 4, 5, 6 or 7. Table A shows the codes of the ring elements of the compound core, Table B lists the bridging units, and Table C lists the symbols of the left and right end groups of the molecule. The acronyms consist of the code of the ring element with the optional linking group, followed by the first hyphen and the code of the left end group, and the second hyphen and the code of the right end group. Table D shows the illustrative structures of the compounds and their respective abbreviations.

[0401] Table D

[0402] Exemplary preferred compounds of formula IA

[0403]

[0404]

[0405] Exemplary preferred compounds of formula IB

[0406]

[0407]

[0408] Exemplary preferred compounds of formula IC-1

[0409]

[0410]

[0411] Exemplary preferred compounds of formula IC-3

[0412]

[0413]

[0414] Other compounds optionally used

[0415]

[0416]

[0417]

[0418]

[0419] Mixture Examples Exemplary mixtures are disclosed below.

[0420] Mixture Example 1

[0421] The following mixture (M-1) was prepared and investigated.

[0422]

[0423] c ) value when cooling,

[0424] When cooled from above the melting point (67°C), the mixture has a unitropic ferroelectric nematic phase from 47°C to about -20°C.

[0425] Mixture Example 2

[0426] The following mixture (M-2) was prepared and investigated.

[0427]

[0428] c ) value when cooling,

[0429] Mixture Example 3

[0430] The following mixture (M-3) was prepared and investigated.

[0431]

[0432]

[0433] c ) value when cooling, Mixture Example 4

[0434] The following mixture (M-4) was prepared and investigated.

[0435]

[0436] c ) value when cooling, Mixture Example 5

[0437] The following mixture (M-5) was prepared and investigated.

[0438]

[0439]

[0440] c ) value when cooling,

[0441] Mixture Example 6

[0442] The following mixture (M-6) was prepared and investigated.

[0443]

[0444] c ) value when cooling,

[0445] Device Example 1

[0446] A capacitor comprising two glass substrates with ITO electrodes was filled with a 110 μm dielectric layer consisting of the dielectric of Mixture Example 4. The capacitance was determined to be 1.41 μF using a 10 Hz AC voltage. The relative dielectric constant (ε r ) is 4.0·10 4 .

Claims

1. A ferroelectric nematic liquid-crystalline medium comprising one or more compounds of the formula IA, in X 1A Indicates -CN, F or -NCS, Z 1A and Z 2A are independently -(CO)-O- or -CF2-O- or a single bond, L 1A is H or CH3, L 2A are independently F or H, L 3A are independently F or H, L 4A are independently F or H, A 1A express R 1A are independently alkyl groups having 1 to 12 C atoms, wherein in addition, one or more CH2 groups in these groups can in each case be replaced independently of one another by -C≡C-, -CF2-O-, -OCF2-, -CH=CH-, -O-, -S-, -(CO)-O- or -O-(CO)- is replaced in such a way that the O / S atoms are not directly connected to each other, and wherein in addition one or more H atoms may be replaced by halogen, or represents H, n1, n2 are independently 0 or 1, and n3 is 2 or 3, and if n1+n2+n3 is 2, then A 1A One or more of 2. A liquid-crystalline medium according to claim 1, comprising one or more compounds selected from the group consisting of formula IB or IC, R 1C -A 3C -Z 2C -A 2C -Z 1C -A 1C -X 1C IC in X 1B Indicates -CN, F or -NCS, X 1C represents -CN, F, CF3, -OCF3, -NCS, SF5 or O-CF=CF2, preferably -CN, Z 1B and Z 2B independently of one another represent a single bond, -(CO)-O- or -CF2-O-, Z 1C and Z 2C One of the two groups represents -(CO)-O- or -CF2-O- and the other represents a single bond, L 1B are independently H or CH3, L 2B is F or H, A 1B express Where L 8B denotes alkyl, alkoxy or alkoxyalkyl, each having 1 to 7 C atoms, A 1C express A 2C express A 3C express and R 1B and R 1C independently of one another represent an alkyl radical having 1 to 12 C atoms, wherein in addition one or more CH2 groups in these radicals can in each case independently of one another be replaced by -C≡C-, -CF2-O-, -OCF2-, -CH=CH-, -O-, -S-, -(CO)-O- or -O-(CO)- is substituted in such a way that the O / S atoms are not directly connected to each other and wherein in addition one or more H atoms may be replaced by halogen; or represents H.

3. The liquid-crystalline medium according to claim 1 or 2, comprising 15% by weight or more of the compound of the formula IA.

4. Liquid-crystalline medium according to one or more of claims 1 to 3, which exhibits a relative dielectric constant ε of 700 or more at 20° C. and 1 kHz. r . 5 . Liquid-crystalline medium according to claim 1 , comprising a total of at least 80% of compounds of the formulae IA, IB and IC.

6. Liquid-crystalline medium according to one or more of claims 1 to 5, which exhibits a ferroelectric nematic phase at least at temperatures of 10°C to 30°C upon cooling from a higher temperature.

7. Liquid-crystalline medium according to one or more of claims 1 to 6, which exhibits a hysteresis of its dielectric properties at varying temperatures.

8. Liquid-crystalline medium according to one or more of claims 1 to 7, which exhibits an interconvertible ferroelectric nematic phase.

9. Use of the liquid-crystalline medium according to at least one of claims 1 to 8 for electro-optical purposes, for supercapacitors and electromechanical devices including generators and actuators.

10. Use of a liquid-crystalline medium according to at least one of claims 1 to 8 in a nonlinear optical element, a sensor or a memory device.

11. Electro-optical liquid-crystal device comprising a liquid-crystal medium according to at least one of claims 1 to 8.

12. A process for producing a liquid-crystalline medium according to any one of claims 1 to 8, wherein at least one or more compounds of the formula IA, optionally one or more compounds selected from the formulae IB and IC and any further components or additives are combined with one another and mixed.

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