Liquid-crystalline medium and electro-optical device

Abstract

The new medium exhibits preferably a ferroelectric nematic phase at ambient temperature. It comprises preferably one or more compounds selected from the group of compounds of formula IA, IB and IC, wherein the variable groups have the meanings indicated herein and in the claims. The use of the medium for providing a ferroelectric nematic material and a method of operation of an electro-optical device are presented. The medium can be suitable for energy saving displays and appliances.

Description

[0001] One aspect of the present invention relates to a liquid crystal medium that exhibits a ferroelectric nematic liquid crystal phase over a considerable temperature range, preferably at ambient temperature. Preferably, these media comprise one or more compounds selected from the group consisting of compounds of formulas IA, IB, and IC as defined below, which maintain the ferroelectric nematic liquid crystal phase. Furthermore, the present invention relates to liquid crystal displays and electro-optical devices containing liquid crystal media according to the present invention, as well as methods for operating electro-optical devices.

[0002] In recent years, the application areas of liquid crystal compounds have expanded significantly to various types of display devices, electro-optical devices, electronic components, sensors, and more. For this reason, many different structures have been proposed, especially in the field of nematic liquid crystals. To date, nematic liquid crystal mixtures have been found to be most widely used in flat panel display devices. They are particularly used in passive TN or STN matrix displays or systems with TFT active matrices, including well-known TN, IPS, FFS, and VA systems.

[0003] Most of these devices utilize nematic liquid crystal phases, including all common LCD televisions, LCD desktop monitors, and mobile LCD devices. Several alternative liquid crystal phases are known, such as ferroelectric smectic phases or blue phases. However, for decades, ferroelectric nematic phases (N... f -LC phase) has only been theoretically assumed, and no suitable liquid crystal materials with such properties have been found. Recently, two chemical structures have been reported to exhibit signs of ferroelectric nematic behavior.

[0004] Hi roya Ni shikawa, Kazuya Shi roshi ta, Hi roki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin-ichi Yamamoto, Koki Sago and Hi rotsugu Kikuchi, Adv. Mater. 2017, 29, 1702354, describes compound A as exhibiting ferroelectric nematic behavior at temperatures between approximately 45°C and 68°C.

[0005]

[0006] In addition, Nerea Sebas t ián, Luka Cmok, Richard J. Mandle, María Rosar io dela Fuente, Irena Olenik, Mar t in And Alenka Mertel J, Physical Review Letters (2020) 124, 037801 describes compound B, which exhibits similar behavior between about 120 °C and 133 °C.

[0007]

[0008] For N f Further comparison of only two available substances in the -LC phase is presented by Xi Chen et al., PNAS June 23, 2020 117(25)14021-14031. This new N f The significance of the presence of the -LC phase is highlighted by ODLavrentovic, ProcNatAcadSciUSA (2020), 117(26), 14629-14631. However, the observed N f The temperature of the phase is much higher than the ambient temperature.

[0009] To date, ferroelectric nematic liquid crystal phases (N1) with temperatures close to ambient temperature have been observed. f The liquid crystal compound (LC phase) is not described. Ambient temperature, sometimes also referred to as room temperature, is intended to mean a temperature of 20°C.

[0010] N f -LC phases will significantly benefit from adaptability to ambient temperatures in technical applications. Display applications are typically designed to operate at temperatures above and below ambient temperature, or room temperature, for example, 15°C to 25°C, preferably 0°C to 50°C, and preferably with a wider operating range.

[0011] Ferroelectric nematic displays are proposed in DE19629551 A1, however, they do not disclose any specific material that can satisfy the required ferroelectric nematic properties.

[0012] The uses of fluorinated liquid crystal materials are known to those skilled in the art. Various compounds containing two 2,6-difluorinated 1,4-phenylene rings have been described as liquid crystals or mesocrystalline materials, such as those described in disclosures WO 2015 / 101405 A1 and WO 2005 / 019381 A1 and many other disclosures. The compounds presented therein have been well characterized, but no ferroelectric properties have been reported.

[0013] One object of this invention is to find a suitable medium for ferroelectric nematic liquid crystals (N... f Novel and stable compounds and materials for (LC phase media). In particular, the compounds should simultaneously possess N f -LC phase or N f- This phase is supported in an LC medium. It should also have moderate to high optical anisotropy to achieve electro-optic switching effects, such as those using conventional nematic LC media.

[0014] Given the wide range of applications for this type of compound with high dielectric anisotropy (Δε), there is a need for other available compounds, preferably with high-resolution bright spots and low melting points, while exhibiting a wide and suitable temperature range for the ferroelectric nematic phase.

[0015] Therefore, another object of the present invention is to find novel stable compounds suitable for use as components of ferroelectric nematic liquid crystal media, particularly suitable for displays similar to conventional nematic TN, STN, IPS, FFS and TN-TFT displays.

[0016] Furthermore, the objective of the compounds according to the invention is to be thermally and photochemically stable under the main conditions of the application field. As a mesocrystalline material, it should facilitate the mixing of a wide range of mesocrystalline phases, preferably nematic phases, with liquid crystal cocomponents, and especially at low temperatures, readily miscible with mesocrystalline, preferably nematic, base mixtures at least below room temperature.

[0017] Surprisingly, it has been found that the disclosed compound is extremely suitable as an N f - LC media components. They can be used to obtain liquid crystal media requiring particularly high or even extremely high dielectric anisotropy, especially for displays, primarily IPS or FFS displays, and also for TN or STN displays. The compounds used according to the invention are sufficiently stable and colorless. In particular, they are characterized by extremely high dielectric constants and very high dielectric anisotropy (Δε). Due to the high dielectric anisotropy, much lower threshold voltages are required, for example, when used in optical switching components. They have reasonably good solubility in compounds with comparable properties and can be blended with similar compounds almost without restriction. Furthermore, the compounds used according to the invention have high-definition bright spots. These compounds also have relatively low melting points, or can remain stably below their melting points as supercooled melts, thereby promoting the formation of the desired N at even lower temperatures, such as at room temperature and below. f -LC phase.

[0018] The compounds and mixtures provided according to the invention significantly expand the range of liquid crystal materials in general, and from an application perspective, these liquid crystal materials are suitable for preparing ferroelectric nematic liquid crystal mixtures.

[0019] The compounds used according to the present invention have a wide range of applications. Depending on the choice of substituents, these compounds can serve as substrate materials for which liquid crystal media are primarily composed. However, liquid crystal substrate materials from other classes of compounds can also be sequentially added to the provided compounds to, for example, further lower the melting point, affect the dielectric and / or optical anisotropy of such dielectrics, and / or optimize their threshold voltage and / or viscosity.

[0020] Use N f The -LC phase enables LC dielectrics to have extremely short response times compared to conventional nematic LC systems currently used in standard displays. Therefore, this invention can substantially improve components used for displaying moving images. A high dielectric constant is also of interest for the dielectric in the capacitor. The dielectric can be made suitable for energy-efficient displays and other electrical appliances by utilizing its excellent dielectric properties. Low voltage is required compared to the prior art.

[0021] Liquid crystal compounds can be used as components of liquid crystal media, which are especially used in displays based on the principles of twisted cell, guest-subject effect, alignment phase deformation (DAP) or electrically controlled birefringence (ECB) effect, coplanar switching (IPS) effect or dynamic scattering effect. Attached Figure Description

[0022] Figure 1 The graphs show the dielectric properties of mixture Example 5 over a temperature range of 20°C to 105°C. T / ε was measured at 10 Hz and approximately 50 mV. r The graph shows the relative dielectric permittivity ε at different temperatures T during cooling (solid line) and heating (dashed line) operations. r The value of ε. At approximately 20°C to 60°C. r The value of ε is the largest (plateau shape), where it increases towards higher temperatures. r The value of ε drops sharply. r The maximum permittivity is approximately 4.10. 3 .

[0023] In one key aspect, the present invention relates to a liquid crystal medium comprising one, two, three or more compounds selected from the group consisting of compounds of formula IA, IB and IC.

[0024]

[0025] in

[0026] X 1A X 1B and X 1CThe terms CN, F, CF3, -OCF3, SCN, NCS, SF5, or O-CF=CF2 can be represented independently of each other. Preferably, they are -CN, F, -CF3, -OCF3, -Cl, or -NCS, with F or CN being the most preferred.

[0027] Z 1A Z 1B and Z 1C Independently represented as -(C=O)-O- or -CF2-O-, A 1A express

[0028]

[0029] Preferred

[0030]

[0031] Optimal Selection

[0032]

[0033] A 1B express

[0034]

[0035] Preferred

[0036]

[0037] A 1C express

[0038]

[0039] Preferred

[0040]

[0041] Optimal Selection

[0042]

[0043] L 1A L 1B and L 1C They can be represented independently of each other, with H being the preferred representation.

[0044] R 1A R 1B and R 1C Each group independently represents an alkyl group having 1 to 15 carbon atoms, preferably 1 to 7, more preferably 1 to 6, and most preferably 1 to 5 carbon atoms, wherein, in each case, one or more CH2 groups among these groups may be independently converted via -C≡C-, -CF2O-, -OCF2-, -CH=CH-, The substitutions include -O-, -S-, -CO-O-, or -O-CO-, such that the O / S atoms are not directly connected to each other, and additionally, one or more H atoms may be halogenated or represent H.

[0045] Preferably R 1A R 1B and R 1C Each is a halogenated or unsubstituted alkyl group having 1 to 15 C atoms, wherein, in each case, one or more CH2 groups of these groups may be independently substituted with -C≡C- or -CH=CH-.

[0046] The present invention further relates to the use of compounds of formula IA, formula IB and formula IC in liquid crystal media, preferably in ferroelectric nematic media.

[0047] The present invention also relates to liquid crystal media comprising at least one compound of formula I (IA, IB, IC) and any optional additives.

[0048] Another aspect of the present invention is the use of a liquid crystal medium for providing ferroelectric nematic liquid crystal materials.

[0049] In their pure state, the compounds of formulas IA, IB, and IC are colorless and, within a temperature range advantageously set for electro-optic applications, form either themselves or in mixtures as a liquid crystal intermediate phase. The compounds according to the invention enable the realization of a wide range of ferroelectric nematic phases. They also support phases beyond N... f The range of nematic phases. In liquid crystal mixtures, the compounds of formula IA, formula IB, and formula IC used according to the present invention significantly improve optical anisotropy. At the same time, these compounds are characterized by sufficiently good UV stability.

[0050] The group R in each of the formulas IA, IB and IC 1A R 1B and R 1C The various sub-formulas preferably represent alkyl groups having 1 to 8 carbon atoms, alkoxy groups having 1 to 8 carbon atoms, or alkenyl groups having 2 to 8 carbon atoms. These alkyl chains are preferably straight chains or preferably have a chain in the R-phase. 1C In this case, branching is preferably performed at the 2- or 3-position via a single methyl or ethyl substituent. 1A R 1B and R 1C Particularly preferred are straight-chain alkyl groups having 1 to 7 carbon atoms or unbranched alkenyl groups having 2 to 8 carbon atoms, especially unbranched alkyl groups having 1 to 5 carbon atoms.

[0051] Preferred alternative group R 1A R1B and R 1C It is selected from cyclopentyl, 2-fluoroethyl, cyclopropylmethyl, cyclopentylmethyl, cyclopentylmethoxy, cyclobutylmethyl, 2-methylcyclopropyl, 2-methylcyclobutyl, 2-methylbutyl, 2-ethylpentyl and 2-alkoxyethoxy.

[0052] Alternatively, group R 1A R 1B and R 1C It represents H or an alkyl group having 1 to 5 carbon atoms.

[0053] The respective groups X of formulas IA, IB and IC 1A X 1B and X 1C Preferably, it represents CN, F, or CF3, especially for X. 1C The optimal choice is represented by CN.

[0054] Each contains a branched or substituted end group R 1A R 1B and R 1C Compounds of formulas IA, IB, and IC may occasionally be important due to their good solubility in conventional liquid crystal substrate materials. (R group) 1A R 1B and R 1C The preferred components are straight chains, not branched chains.

[0055] Group R 1A R 1B and R 1C The following are particularly preferred selections:

[0056] H

[0057] CH3

[0058] C2H5

[0059] n-C3H7

[0060] n-C4H9

[0061] n-C5H 11

[0062] C2H5CH(CH3)CH2

[0063] n-C6H 13

[0064] n-C7H 15

[0065] n-C3H7CH(C2H5)CH2

[0066] n-C8H17

[0067] c-C3H5

[0068] c-C3H5CH2

[0069] c-C4H7

[0070] c-C5H7

[0071] c-C5H9

[0072] c-C5H9CH2

[0073] CH2=CH

[0074] CH3CH=CH

[0075] CH2=CH(CH2)2

[0076] CH3O

[0077] C2H5O

[0078] n-C3H7O

[0079] n-C4H9O

[0080] and

[0081] n-C5H 11 O

[0082] The following abbreviations are used for end bases:

[0083] c-C3H5

[0084] c-C3H5CH2

[0085] c-C4H7

[0086] c-C5H7

[0087] c-C5H9

[0088] and

[0089] c-C5H9CH2

[0090] In a preferred embodiment, the medium according to the invention preferably comprises one, two, three or more compounds of formula IA.

[0091]

[0092] Preferably selected from the group consisting of formulas IA-1 to IA-3, more preferably selected from the group consisting of formula IA-1 or IA-2, and most preferably selected from the group consisting of formula IA-2:

[0093]

[0094] The parameters have the meanings given above, and preferably...

[0095] Z 1A This represents -CF2-O-, and

[0096] X 1A It can be represented as -CN or F, preferably -CN.

[0097] And especially in formula IA-2, the preferred alternative is...

[0098] X 1A It represents F.

[0099] The mixture preferably contains 40 wt% or more, more preferably 45 wt% or more, and even more preferably 50 wt% or more of a compound of formula IA.

[0100] In a preferred embodiment, the medium according to the invention preferably comprises one, two, three or more compounds of formula IB.

[0101]

[0102] The preferred selection is from the group consisting of formulas IB-1 and IB-2, with a particular preference for the group consisting of formula IB-2:

[0103]

[0104] The parameters have the meanings given above, and preferably...

[0105] Z 1B This represents -CF2-O-, and

[0106] X 1B Indicates -CN,

[0107] And especially in formula IB-2, Z is the preferred alternative. 1B Represents -(C=O)-O-, and

[0108] X 1A It represents F.

[0109] In a preferred embodiment, the medium according to the invention preferably comprises one, two, three or more IC compounds.

[0110]

[0111] Preferably selected from the group consisting of formulas IC-1 to IC-3, more preferably selected from the group consisting of formulas IC-2 and IC-3, and most preferably selected from the group consisting of formula IC-3:

[0112]

[0113] The parameters have the meanings given above, and preferably...

[0114] Z 1C This represents (C=O)-O-, and

[0115] X 1C The designation is -CN, and particularly in formula IC-2, preferably alternatively.

[0116] Z 1C Represents -CF2O-, and

[0117] X 1C It represents F.

[0118] The particularly preferred IC compounds used in the medium are compounds of formulas IC-3.1 to IC-3.20.

[0119]

[0120]

[0121]

[0122]

[0123] And further, compounds of formulas IC-3.21 to IC-3.26

[0124]

[0125] The preferred IC compound used in the medium is a compound of the following formula:

[0126]

[0127] as well as

[0128]

[0129] In a preferred embodiment of the invention, the medium comprises 15 wt% or more of one or more compounds of formula IA-3-N.

[0130]

[0131] And optionally, preferably 5 wt%, more preferably 15 wt% or more of one or more compounds of formula IA-3-F,

[0132]

[0133] And optionally, preferably 15 wt%, more preferably 20 wt% or more of one or more compounds selected from formula C1

[0134]

[0135] in

[0136] X 13 It can be represented as -CN or -NCS, with -CN being preferred.

[0137] X 1C The symbol -CN, F, CF3, -OCF3, -NCS, SF5, or O-CF=CF2 is preferred, and -CN or F is the most preferred.

[0138] Z 1A It represents -(CO)-O- or -CF2-O-.

[0139] Z 1C It is -(CO)-O- or -CF2-O-.

[0140] L 1A and L 1C They can be represented independently of each other, with H being the preferred representation.

[0141] A 1A express

[0142]

[0143] Preferred

[0144]

[0145] Optimal Selection

[0146]

[0147] A 1C Independently represent

[0148]

[0149] Preferred

[0150]

[0151] Optimal Selection

[0152]

[0153] R 1A and R 1CEach group independently represents an alkyl group having 1 to 12 carbon atoms, preferably 1 to 8, more preferably 1 to 6, and most preferably 1 to 5 carbon atoms, wherein, in each case, one or more CH2 groups among these groups may be independently converted via -C≡C-, -CF2-O-, -OCF2-, -CH=CH-, The substitutions are -O-, -S-, -(CO)-O-, or -O-(CO)-, in a manner that prevents the O / S atoms from being directly bonded to each other. Additionally, one or more H atoms may be substituted with halogens or represent H.

[0154] Preferably R 1A R 1B and R 1C Independently, it is a halogenated or unsubstituted alkyl group having 1 to 10 C atoms, wherein one or more CH2 groups in these groups may be substituted with -O- or -CH=CH- in such a way that the O atom is not directly attached.

[0155] In a preferred embodiment of the invention, the medium comprises up to 100% of one or more compounds, preferably two, three or more compounds, selected from the group I compounds, the group consisting of compounds of formula IA, IB and IC. In this embodiment, the medium is preferably composed primarily of these compounds, more preferably substantially of these compounds, and most preferably almost entirely of these compounds. In this embodiment, the concentration of these group I compounds is preferably in the range of 50% or higher, preferably 60% or higher, up to 100% or lower.

[0156] For the purposes of this invention, unless otherwise indicated in each case, the following definitions shall apply in conjunction with the description of the components of the composition:

[0157] - "Contains": The concentration of the component discussed in the composition is preferably 5% or higher, particularly preferably 10% or higher, and very particularly preferably 20% or higher.

[0158] - "Mainly composed of": The concentration of the component discussed in the composition is preferably 50% or higher, particularly preferably 55% or higher, and very particularly preferably 60% or higher.

[0159] - "consisting essentially of": The concentration of the component discussed in the composition is preferably 80% or higher, particularly preferably 90% or higher, and very particularly preferably 95% or higher, and

[0160] - "consisting of almost entirely of": The concentration of the component discussed in the composition is preferably 98% or higher, particularly preferably 99% or higher, and very particularly preferably 100.0%.

[0161] Preferably, the medium according to this application satisfies one or more of the following conditions. It preferably includes...

[0162] - One, two, three or more compounds of formula IA,

[0163] - One, two, three or more compounds of formula IA, wherein X 1A For F,

[0164] - One, two, three or more compounds of formula IA, wherein X 1A The content of CN is preferably at least 15 wt%, more preferably at least 25 wt%, and most preferably at least 30 wt%.

[0165] - One, two, three or more IB compounds,

[0166] - One, two, three or more IC compounds,

[0167] - One, two, three or more IC compounds, wherein X 1c The CN value is preferably at least 35% by weight or more, more preferably 45% by weight, 55% by weight or 65% by weight or more.

[0168] - One, two, three or more compounds of formula IA, wherein X 1A CN represents one, two, three or more compounds of formula IA (where X) 1A Indicates the combination of F).

[0169] - One, two, three or more compounds of formula IA-1, preferably compounds of formula AUUQU-nN, most preferably selected from the group consisting of compounds AUUQU-2-N, AUUQU-3-N, AUUQU-4-N and AUUQU-5-N, and / or

[0170] - One, two, three or more compounds of formula IA-2, preferably compounds of formula DUUQU-nN and / or DUUQU-nF, most preferably selected from the group consisting of: DUUQU-2-N, DUUQU-3-N, DUUQU-4-N, DUUQU-5-N, DUUQU-6-N, DUUQU-7-N, DUUQU-2-F, DUUQU-4-F, DUUQU-5-F and DUUQU-6-F, and / or

[0171] - One, two, three or more compounds of formula IA-3, preferably compounds of formula GUUQU-nN, more preferably compounds of formulas GUUQU-0-N, GUUQU-1-N, GUUQU-2-N, GUUQU-3-N, GUUQU-4-N or GUUQU-5-N, most preferably compound GUUQU-3-N, and / or - One, two, three or more compounds of formula IA-3, preferably compounds of formula GUUQU-nF, most preferably compounds GUUQU-2-N, GUUQU-3-N, GUUQU-4-N or GUUQU-5-N, and / or

[0172] - One, two, three or more compounds of the formula IB-2, preferably compounds of the formula GUQGU-nN, more preferably compounds of the formula GUQGU-3-N, and / or

[0173] - One, two, three or more compounds of the IC-2 formula, preferably of the formula MUZU-nF, most preferably of the compounds MUZU-4-F and / or MUZU-5-F, and / or

[0174] - One, two, three or more IC-3 compounds, preferably compounds of the formula UUZU-nN and / or UUQU-nN, most preferably selected from the group consisting of compounds UUZU-4-N, UUZU-5-N and UUQU-4-N, and further selected from UUZU-0-N, UUZU-1-N, UUZU-2-N, UUZU-3-N, UUQU-0-N, UUQU-1-N, UUQU-2-N, UUQU-3-N and UUQU-5-N.

[0175] In a preferred embodiment of the present invention, the compounds of formula IA, formula IB and formula IC are the first group of compounds, i.e., the first group of compounds.

[0176] In one embodiment of the invention, the medium optionally, preferably complies with one or more compounds selected from the group consisting of:

[0177] Optionally, preferably mandatory, alternatively, or otherwise, one or more, preferably two, three, or more, compounds other than those of formulas IA, IB, and IC (i.e., Group 1 compounds), selected from Group 2, i.e., the group of compounds of formulas II and III, preferably at a concentration of more than 0% to 50% or less.

[0178]

[0179]

[0180] in

[0181] R 2 This indicates an alkyl group having 1 to 15 carbon atoms, preferably 1 to 7, more preferably 1 to 6, and most preferably 1 to 5 carbon atoms, wherein, in each case, one or more CH2 groups in these groups may be independently converted to C≡C-, -CF2O-, -OCF2-, -CH=CH-, The substitutions include -O-, -S-, -CO-O-, or -O-CO-, such that the O / S atoms are not directly connected to each other, and additionally, one or more H atoms may be halogenated or represent H.

[0182] Preferably, it represents an alkyl, alkoxy, fluorinated alkyl, or fluorinated alkoxy group having 1 to 7 carbon atoms; or an alkenyl, alkenoxy, alkoxyalkyl, or fluorinated alkenyl group having 2 to 7 carbon atoms, and more preferably, it represents an alkyl or alkenyl group.

[0183] and

[0184] Each time it appears, it represents independently of each other.

[0185]

[0186] Preferred

[0187]

[0188] L 21 and L 22 Indicates H or F,

[0189] Preferred L 21 F represents

[0190] X 2 The symbol represents a halogen, a halogenated alkyl or alkoxy group having 1 to 3 carbon atoms, or a halogenated alkenyl or alkenyloxy group having 2 or 3 carbon atoms, preferably F, Cl, -OCF3, -O-CH2CF3, -O-CH=CH2, -O-CH=CF2 or -CF3, and very preferably F, Cl, -O-CH=CF2 or -OCF3.

[0191] m represents 0, 1, 2, or 3, preferably 1 or 2, and especially preferably 2.

[0192] R 3 This indicates an alkyl group having 1 to 15 carbon atoms, preferably 1 to 7, more preferably 1 to 6, and most preferably 1 to 5 carbon atoms, wherein, in each case, one or more CH2 groups in these groups may be independently converted to C≡C-, -CF2O-, -OCF2-, -CH=CH-, The substitutions include -O-, -S-, -CO-O-, or -O-CO-, such that the O / S atoms are not directly connected to each other, and additionally, one or more H atoms may be halogenated or represent H.

[0193] Preferably, it represents an alkyl, alkoxy, fluorinated alkyl, or fluorinated alkoxy group having 1 to 7 carbon atoms; or an alkenyl, alkenyloxy, alkoxyalkyl, or fluorinated alkenyl group having 2 to 7 carbon atoms, and more preferably, a n-alkyl, cyclopropyl, cyclopentyl, or alkenyl group.

[0194] and

[0195] Each time it appears, it is independent of each other.

[0196]

[0197] Preferred

[0198]

[0199] L 31 and L 32 H or F can be represented independently of each other, with L being preferred. 31 F represents

[0200] X 3 The term represents a halogen, a halogenated alkyl or alkoxy group having 1 to 3 carbon atoms, or a halogenated alkenyl or alkenyloxy group having 2 or 3 carbon atoms, F, Cl, -OCF3, -OCHF2, -O-CH2CF3, -O-CH=CF2, -O-CH=CH2 or -CF3, with F, Cl, -O-CH=CF2, -OCHF2 or -OCF3 being particularly preferred.

[0201] Z 3 This indicates -CH2CH2-, -CF2CF2-, -(CO)O-trans-CH=CH-, trans-CF=CF-, -CH2O-, or a single bond, preferably -CH2CH2-, -(CO)O-trans-CH=CH-, or a single bond, and very preferably -(CO)-O-trans-CH=CH-, or a single bond.

[0202] n represents 0, 1, 2, or 3, preferably 1, 2, or 3, and especially preferably 1.

[0203] Each ring, and preferably the phenylene ring, may optionally be substituted with one or two alkyl groups, preferably with methyl and / or ethyl groups, and preferably with one methyl group, and in particular the ring

[0204] Can be passed Alternative

[0205] And especially this ring

[0206] Can be passed Alternative,

[0207] Furthermore, compounds of formulas IA, IB, and IC are not included in compounds of formula II.

[0208] Similarly, optionally, preferably mandatory, alternatively, or otherwise, one or more compounds, preferably two, three, or more compounds, selected from Group 3, i.e., the group containing compounds of formulas IV and V, preferably at a concentration exceeding 0% to 20%, preferably not exceeding 10%.

[0209]

[0210] in

[0211] R 41 and R 42 Each of these groups independently represents an alkyl group having 1 to 15 C atoms, preferably 1 to 7, more preferably 1 to 6, and most preferably 1 to 5 C atoms, wherein, in each case, one or more CH2 groups among these groups may be independently converted via -C≡C-, -CF2O-, -OCF2-, -CH=CH-, The substitutions include -O-, -S-, -CO-O-, or -O-CO-, such that the O / S atoms are not directly connected to each other, and additionally, one or more H atoms may be halogenated or represent H.

[0212] Preferably, it has the above-mentioned formula II regarding R. 2 The meaning indicated

[0213] Preferred R 41 Indicates alkyl and R 42 Indicates alkyl or alkoxy, or R 41 Indicates alkenyl and R 42 Indicates alkyl group,

[0214] and

[0215] Independently, and if

[0216] Appeared twice.

[0217] These are also represented independently of each other.

[0218]

[0219]

[0220] Preferred

[0221] and One or more of them

[0222] express

[0223]

[0224] Z 41 and Z 42 Independent of each other, and if Z 41 If these appear twice, they independently represent -CH2CH2-, -(CO)O-, trans-CH=CH-, trans-CF=CF-, -CH2O-, -CF2O-, -C≡C-, or a single bond, preferably one or more of them representing a single bond.

[0225] p represents 0, 1, or 2, preferably 0 or 1, and

[0226] R 51 and R 52 They independently possess information about R 41 and R 42 The meaning given is one of the following, and preferably refers to an alkyl group having 1 to 7 carbon atoms, preferably a n-alkyl group, and particularly preferably a n-alkyl group having 1 to 5 carbon atoms; an alkoxy group having 1 to 7 carbon atoms, preferably a n-alkoxy group, and particularly preferably a n-alkoxy group having 2 to 5 carbon atoms; or an alkoxyalkyl group, alkenyl group, or alkenyloxy group having 2 to 7 carbon atoms, preferably having 2 to 4 carbon atoms, preferably an alkenyloxy group.

[0227] to

[0228] If they exist, then each is represented independently.

[0229]

[0230] Preferred

[0231]

[0232] Preferred

[0233] express And, if it exists,

[0234] Preferred representation

[0235] Z 51 To Z 53Each of these elements independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -(CO)O-, or a single bond, preferably -CH2-CH2-, -CH2-O-, or a single bond, and especially preferably a single bond.

[0236] i and j each represent 0 or 1 independently, (i+j) preferably represents 0, 1 or 2, more preferably 0 or 1, and most preferably 1.

[0237] Each ring, and preferably the phenylene ring, may optionally be substituted with one or two alkyl groups, preferably with methyl and / or ethyl groups, and preferably with one methyl group.

[0238] Similarly, optionally, preferably mandatory, alternatively, or otherwise, one or more compounds, preferably two, three, or more compounds, selected from Group 4, i.e., the group consisting of compounds of Formulas I and VI to IX, preferably at a concentration exceeding 0% to 20%.

[0239]

[0240]

[0241] in

[0242] express

[0243]

[0244]

[0245] express

[0246]

[0247] Preferred

[0248]

[0249] n represents 0 or 1,

[0250] R 11 and R 12 The terms "alkyl", "alkoxy", "fluorinated alkyl", or "fluorinated alkoxy" are independently represented, preferably having 1 to 7 carbon atoms, wherein one of the CH2 groups may be replaced by 1,2-cyclopropyl, 1,3-cyclopentyl, or 1,3-cyclopentenyl, and "alkenyl", "alkenyl", "alkoxyalkyl", or "fluorinated alkenyl" having 2 to 7 carbon atoms, and are preferably alkyl, alkoxy, alkenyl, or alkenyl, with alkyl, alkoxy, or alkenyl being the most preferred.

[0251] R 61This refers to an unsubstituted alkyl group having 1 to 7 carbon atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, and most preferably propyl or pentyl; an unsubstituted alkenyl group having 2 to 7 carbon atoms, preferably a straight-chain alkenyl group, and particularly preferably having 2 to 5 carbon atoms; an unsubstituted alkoxy group having 1 to 6 carbon atoms or an unsubstituted alkenoxy group having 2 to 6 carbon atoms.

[0252] R 62 This refers to an unsubstituted alkyl group having 1 to 7 carbon atoms, an unsubstituted alkoxy group having 1 to 6 carbon atoms, or an unsubstituted olefinic group having 2 to 6 carbon atoms.

[0253] l represents 0 or 1.

[0254] R 71 This indicates an unsubstituted alkyl group having 1 to 7 carbon atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, and most preferably propyl or pentyl; or an unsubstituted alkenyl group having 2 to 7 carbon atoms, preferably a straight-chain alkenyl group, and particularly preferably having 2 to 5 carbon atoms.

[0255] R 72 This indicates an unsubstituted alkyl group having 1 to 7 carbon atoms, preferably 2 to 5 carbon atoms; an unsubstituted alkoxy group having 1 to 6 carbon atoms, preferably 1, 2, 3, or 4 carbon atoms; or an unsubstituted olefinic group having 2 to 6 carbon atoms, preferably 2, 3, or 4 carbon atoms. express

[0256]

[0257] R 81 This indicates an unsubstituted alkyl group having 1 to 7 carbon atoms, preferably a straight-chain alkyl group, more preferably a n-alkyl group, and most preferably propyl or pentyl; or an unsubstituted alkenyl group having 2 to 7 carbon atoms, preferably a straight-chain alkenyl group, and particularly preferably having 2 to 5 carbon atoms.

[0258] R 82 This indicates an unsubstituted alkyl group having 1 to 7 carbon atoms, preferably 2 to 5 carbon atoms; an unsubstituted alkoxy group having 1 to 6 carbon atoms, preferably 1, 2, 3, or 4 carbon atoms; or an unsubstituted olefinic group having 2 to 6 carbon atoms, preferably 2, 3, or 4 carbon atoms.

[0259] express

[0260]

[0261] Preferred

[0262]

[0263] More

[0264]

[0265] Z 8 This represents -(C=O)-O-, -CH2-O-, -CF2-O-, or -CH2-CH2-, preferably -(C=O)-O- or -CH2-O-, and

[0266] o represents 0 or 1.

[0267] R 91 and R 92 They are independent of each other and possess the characteristics mentioned above regarding R. 72 The meaning given,

[0268] R 91 Preferably, it refers to an alkyl group having 2 to 5 carbon atoms, more preferably having 3 to 5 carbon atoms.

[0269] R 92 Preferably, it refers to an alkyl or alkoxy group having 2 to 5 carbon atoms, more preferably an alkoxy group having 2 to 4 carbon atoms, or an olefinic group having 2 to 4 carbon atoms.

[0270] express

[0271] p and q represent 0 or 1 independently, and

[0272] (p+q) preferably represents 0 or 1, if express

[0273] Alternatively, p = q = 1 is preferred.

[0274] Each ring, and preferably the phenylene ring, may optionally be substituted with one or two alkyl groups, preferably with methyl and / or ethyl groups, and preferably with one methyl group.

[0275] And especially this ring

[0276] alternative Alternative,

[0277] Furthermore, compounds of formula VIII are not included in compounds of formula X, and compounds of formula VI are not included in compounds of formulas VII to X.

[0278] Similarly, optionally, preferably mandatory, alternatively, or otherwise, one or more compounds, preferably two, three, or more compounds, selected from Group 5, i.e., the group containing compounds of formula B, preferably at a concentration exceeding 0% to 20%.

[0279]

[0280] in

[0281] express

[0282]

[0283] Each occurrence is represented independently.

[0284]

[0285]

[0286] Preferred

[0287] Optimal Selection

[0288] n represents 0, 1, or 2, preferably 1.

[0289] R 1 The term indicates an alkyl group having 1 to 7 carbon atoms, wherein one or more CH2 groups, preferably one CH2 group, may be independently substituted with -C≡C-, -CF2O-, -OCF2-, -O-, -(CO)-O-, -O-(C=O)-, cyclopropylene, 1,3-cyclobutylene, 1,3-cyclopentylene, or 1,3-cyclopentenylene, preferably with cyclopropylene or 1,3-cyclopentylene, and preferably one CH2 group may be substituted with 1,2-cyclopropylene. The substitution of 1,3-cyclopentyl or 1,3-cyclopentenyl represents an alkenyl, alkenyloxy, alkoxyalkyl, or fluorinated alkenyl group having 2 to 7 carbon atoms, preferably alkyl or alkenyl, wherein one of the -CH2- groups may be substituted with cyclopropyl, 1,3-cyclobutyl, 1,3-cyclopentyl, or 1,3-cyclopentenyl, preferably with cyclopropyl or 1,3-cyclopentenyl, in such a manner that the O atoms are not directly connected to each other, and one or more of the H atoms may be substituted with halogens.

[0290] X 1 The groups represent F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy, or fluorinated, with the latter four groups preferably having 1 to 4 carbon atoms, more preferably representing F, Cl, CF3, or OCF3, and

[0291] Each ring, and preferably the phenylene ring, may optionally be substituted with one or two alkyl groups, preferably with methyl and / or ethyl groups, and preferably with one methyl group.

[0292] Preferably, the medium comprises one or more compounds from Group 1 and Group 2, compounds from Group 1 and Group 3, or compounds from Group 1 and Group 4, more preferably compounds from Group 1 and Group 2, or compounds from Group 1 and Group 3.

[0293] It is also particularly preferred that the medium contains one or more compounds of Group 1, Group 2 and Group 3, or compounds of Group 1, Group 2 and Group 4, and more preferably compounds of Group 1, Group 2 and Group 3.

[0294] Compounds from groups 1, 2, 3, and 4 with a molecular weight of 425 or greater are preferred, and more preferably 450 or greater. In the liquid crystal medium according to the invention, the content of compounds with a molecular weight less than 425, more preferably less than 450, is preferably 10% by weight or less, more preferably 5% by weight or less. The liquid crystal medium according to the invention is preferably composed substantially of compounds with a molecular weight of 450 or greater, more preferably 470 or greater.

[0295] For illustration, the following compounds and their molecular weights are provided:

[0296] Table: Structure and Molecular Weight

[0297]

[0298] Compounds of formula IC can be prepared by methods known per se, specifically under known and suitable reaction conditions, as described in the literature (e.g., in standard works such as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart). Variations known per se may also be used herein, which are not described in more detail.

[0299] Generally speaking, compounds of formula I, and especially compounds of formula I, can be advantageously prepared as shown in the following illustrative synthesis and examples (Schemes 1 and 2).

[0300]

[0301] Scheme 1. Preparative IC compound (Z) 1C =-C(O)O-) general synthesis scheme, and R 1C and X 1C It is based on the IC definition.

[0302] This synthetic scheme 2 presents an alternative reaction route for the preparation of the corresponding difluoromethyleneoxy (-CF2-O-) compounds.

[0303]

[0304] Scheme 2. Preparative IC compound (where Z) 1C A general synthetic scheme for (=-CF2O-), and R 1C and X 1C It is based on the IC definition.

[0305] The corresponding starting materials are generally readily prepared by those skilled in the art using synthetic methods known from the literature or are commercially available.

[0306] The reaction methods and reagents used are known in principle from the literature. Other reaction conditions are illustrated through examples.

[0307] Other preferred method variations not mentioned above are disclosed through embodiments or claims.

[0308] The reaction mixture obtained by the above methods and subsequent processing can be carried out substantially in batch or continuous reaction processes. Continuous reaction processes encompass reactions, for example, in continuous stirred tank reactors, cascaded stirred tank reactors, circulating or cross-flow reactors, flow tubes, or microreactors. The reaction mixture may optionally (as needed) be processed by: solid-phase filtration, chromatography, separation between immiscible phases (e.g., extraction), adsorption onto a solid support; removal of solvents and / or azeotropic mixtures by distillation, selective distillation, sublimation, crystallization, co-crystallization, or by nanofiltration over a membrane.

[0309] In this invention, the 2,5-disubstituted dioxane ring of the following formula...

[0310]

[0311] Preferably, the dioxane ring represents the 2,5-trans configuration, meaning that the substituents R are preferably all located in the equatorial position of the preferred chair conformation. The following formula represents a 2,5-disubstituted tetrahydropyran.

[0312]

[0313] Similarly, the tetrahydropyran ring representing the 2,5-trans configuration is preferred, i.e., the substituents are preferably all located in the equatorial position in the preferred chair conformation.

[0314] The present invention also relates to liquid crystal media comprising one or more of the compounds of formula I (formulas IA, IB, and IC) according to the invention. The liquid crystal medium preferably comprises at least two components, each preferably having a ferroelectric nematic phase. It is preferably obtained by mixing the components with each other. Therefore, the method of the present invention for preparing a liquid crystal medium is characterized by mixing at least one compound of formula I (formulas IA, IB, and IC) with at least one other preferably ferroelectric nematic mesocrystalline compound, and optionally adding additives.

[0315] For liquid crystal media containing compounds of type IA and / or type IB and / or type IC, the achievable combination of temperature range, clearing point, dielectric anisotropy, and response time of the ferroelectric nematic phase is far superior to that of prior art materials of this type. Previously, only single compound materials were available, with limited choices, none of which possessed a ferroelectric nematic phase range within a suitable temperature range.

[0316] The mixtures according to the invention typically exhibit a very wide range of nematic phases, with a clearing point of 65°C or higher, and also a wide range of ferroelectric nematic phases.

[0317] The liquid crystal medium according to the invention preferably exhibits a temperature range of ferroelectric nematic phases with a width of 20°C or greater, preferably extending to 30°C or greater, more preferably 40°C or greater. Each phase range may be single-variable or double-variable, preferably double-variable.

[0318] Preferably, the liquid crystal medium according to the present invention preferably displays a ferroelectric nematic phase.

[0319] From 20°C or lower to 30°C or higher, more preferably

[0320] From 10°C or lower to 40°C or higher, more preferably

[0321] From 0°C or lower to 50°C or higher, and preferably,

[0322] From -20°C or lower to 60°C or higher.

[0323] In another preferred embodiment, the liquid crystal medium according to the invention preferably exhibits a ferroelectric nematic phase.

[0324] From 20°C or lower to 30°C or higher, more preferably

[0325] From 10°C or lower to 35°C or higher, more preferably

[0326] From 0°C or lower to 40°C or higher, and preferably,

[0327] From -20°C or lower to 45°C or higher.

[0328] In another preferred embodiment, the liquid crystal medium according to the invention preferably exhibits a ferroelectric nematic phase.

[0329] From 20°C or lower to 50°C or higher, preferably

[0330] From 10°C or lower to 70°C or higher, more preferably

[0331] From 0°C or lower to 90°C or higher, and preferably,

[0332] From -20°C or lower to 100°C or higher.

[0333] This means that the medium displays N at least at a given interval. f Mutually.

[0334] The liquid crystal medium according to the present invention exhibits excellent dielectric properties.

[0335] Preferably, its ε || The value is in the range of 1,400 to 10,000, more preferably 1,600 to 3,000, more preferably 1,800 to 2,600, and most preferably 2,000 to 2,500.

[0336] Preferably, its ε ⊥ The value is in the range of 1,000 to 2,300, more preferably 1,200 to 2,100, more preferably 1,400 to 2,300, and most preferably 1,500 to 2,500.

[0337] Preferably, the value of Δε is 300 or higher, more preferably 400 to 2,100, more preferably 1,400 to 2,300, and most preferably 1,500 to 2,500.

[0338] Preferably, at 10 Hz, its ε r The value is 20,000 or higher, more preferably 25,000 to 90,000, more preferably 30,000 to 75,000, and most preferably 38,000 to 60,000.

[0339] These dielectric properties are achieved at temperatures where the dielectric is in the ferro-nematic phase. The dielectric characteristics can exhibit hysteretic behavior, and in that case, the values ​​obtained at a given temperature can depend on the material's history, i.e., whether the material has been heated or cooled.

[0340] Among other things, this effect enables the device to operate, for example, in a bistable mode, which can be advantageously used in electro-optic devices, such as those known from ferroelectric smectic devices.

[0341] The liquid crystal medium according to the invention preferably contains 2 to 40, particularly preferably 4 to 20, compounds as other components besides one or more compounds according to the invention. In particular, these media may contain 1 to 25 components besides one or more compounds according to the invention. These other components are preferably selected from ferroelectric nematic or nematic (univariant or isotropic) materials.

[0342] Existing ferroelectric materials and similar compounds with high dielectric anisotropy used in combination with current materials are selected from, for example, the following structures:

[0343]

[0344]

[0345] Where p is 1, 2, 3, 4 or 5.

[0346] The medium according to the invention preferably contains 1% to 100%, more preferably 10% to 100%, and especially preferably 50% to 100% of compounds of formula IA and / or formula IB and / or formula IC.

[0347] The liquid crystal mixtures according to the invention are prepared in a conventional manner. Generally, the required amount of the component used in a small quantity is dissolved in the component constituting the main component, preferably dissolved at a high temperature. The component can also be mixed in an organic solvent, such as a solution in acetone, chloroform, or methanol, and after thorough mixing, the solvent is removed, for example, by distillation. In addition, the mixtures can be prepared by other conventional methods, such as by using premixes, such as homologue mixtures, or using a so-called "multi-bottle" system.

[0348] The liquid crystal mixture may also contain other additives known to those skilled in the art and described in the literature. For example, 0 to 15%, preferably 0 to 10%, of multicolor dyes, chiral dopants, stabilizers, or nanoparticles may be added. The individual compounds added are used at a concentration of 0.01 to 6%, preferably 0.1 to 3%. However, the concentration data for other components of the liquid crystal mixture (i.e., liquid crystals or mesocrystalline compounds) are given here without considering the concentrations of these additives.

[0349] The liquid crystal mixtures according to the present invention can significantly broaden the range of available parameters.

[0350] The present invention also relates to electro-optic displays containing this type of medium (especially TFT displays having two planar parallel outer plates forming a cell together with a frame, an integrated nonlinear assembly for switching individual pixels on the outer plates, and a ferroelectric nematic liquid crystal material having positive dielectric anisotropy and high resistivity located in the cell). The present invention further relates to the use of these media for electro-optic purposes.

[0351] The term "alkyl" encompasses both unbranched and branched alkyl groups having 1 to 15 carbon atoms, particularly and preferably unbranched groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and n-heptyl, and alternatively, groups substituted with one methyl, ethyl, or propyl group such as n-butyl, n-pentyl, n-hexyl, and n-heptyl. Groups having 2 to 5 carbon atoms are generally preferred.

[0352] The term "alkenyl" encompasses both unbranched and branched alkenyl groups having up to 15 carbon atoms, with a particular emphasis on unbranched groups. Particularly preferred alkenyl groups are C2-C7-1E-alkenyl, C4-C7-3E-alkenyl, C5-C7-4-alkenyl, C6-C7-5-alkenyl, and C7-6-alkenyl, especially C2-C7-1E-alkenyl, C4-C7-3E-alkenyl, and C5-C7-4-alkenyl. Examples of preferred alkenyl groups include 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 the like. Groups having 2 to 5 carbon atoms are generally preferred.

[0353] The term "halogenated alkyl" preferably encompasses monofluorinated or polyfluorinated and / or chlorinated groups. This includes fully halogenated groups. Fluorinated alkyl groups are particularly preferred, especially CF3, CH2CF3, CH2CHF2, CHF2, CH2F, CHFCF3, and CF2CHFCF3. The term "halogenated alkenyl" and related expressions are explained accordingly.

[0354] The total amount of each of the formula IA and / or formula IB and / or formula IC compounds in the mixtures of the present invention is not critical. Therefore, the mixtures may contain one or more other components for the purpose of optimizing various properties.

[0355] The matrix display constructed according to the invention, consisting of a polarizer, an electrode substrate, and surface-treated electrodes, corresponds to a common design for such displays. The term "common design" is used broadly herein and also encompasses all derivatives and variations of matrix displays, particularly matrix display assemblies based on polycrystalline silicon TFTs.

[0356] However, the fundamental difference between the display according to the present invention and conventional twisted nematic cell-based displays to date lies in the selection of liquid crystal parameters of the liquid crystal layer.

[0357] The following embodiments illustrate the invention but are not intended to limit it. Those skilled in the art will be able to discover working details not given in detail in the general description from the embodiments, and summarize them based on general expert knowledge and apply them to specific problems.

[0358] In the foregoing and hereinafter, percentage data are expressed as weight percentages. Unless otherwise expressly indicated, all temperature values ​​indicated in this application, such as melting point T(C,N), phase transition from smectic (Sm) to nematic (N) T(S,N), and clearing point T(N,I) or T(N), are not expressed as weight percentages. f All values ​​(C, I) are indicated in degrees Celsius (°C), and all temperature differences are indicated accordingly in different degrees (° or degrees). Furthermore, C = crystalline state, N = nematic phase, Nf = ferroelectric nematic phase, Sm = smectic phase (especially SmA, SmB, etc.), Tg = glass transition temperature, and I = isotropic phase. The data between these symbols represent the transition temperature. Δn represents optical anisotropy (589 nm, 20 °C), and Δε represents dielectric anisotropy (1 kHz, 20 °C).

[0359] Physical, physicochemical, and electro-optical parameters are determined by generally known methods, such as those described in the handbook "MerckLiquidCrystals-". -Physical Properties of Liquid Crystals-Descriptive of the Measurement Methods", 1998, Merck KGaA, Darms tadt.

[0360] The appearance of the ferroelectric nematic phase of the material is identified by differential scanning calorimetry (DSC) through observation of the texture under a polarizing microscope equipped with a hot stage for controlled cooling or heating, and further confirmed by temperature dependence determination of dielectric properties.

[0361] The dielectric anisotropy Δε of each substance was measured at 20 °C and 1 kHz. For this purpose, 5 to 10 wt% of the substance under study dissolved in the dielectric positive mixture ZLI-4792 (Merck KGaA) was measured, and the measurements were extrapolated to 100% concentration. The optical anisotropy Δn was determined by linear extrapolation at 20 °C and a wavelength of 589.3 nm.

[0362] The dielectric permittivity (ε) of the material, particularly in the ferroelectric nematic phase, was directly determined by measuring the capacitance of at least one test cell containing the compound and having a cell thickness of 25 μm, with both vertical and planar orientations. Temperature was controlled using a Novocontrol Novocool system set to apply temperature gradients of + / -1 K / min, + / -2 K / min, + / -5 K / min, and + / -10 K / min to the sample cell. Capacitance was measured using a Novocontrol α-N analyzer at frequencies of 10 Hz or 1 kHz, with typical voltages decreasing from <50 mV to 0.1 mV to ensure the values ​​were below the threshold of the compound under study. Measurements were performed during sample heating and cooling. For simplicity, relative dielectric permittivity (ε) is used here. r ), which is defined as

[0363] ε r =ε / ε0.

[0364] In this application, unless otherwise expressly indicated, the plural form of a term refers to both the singular and plural forms, and vice versa. According to the specification, other combinations of embodiments and variations of the invention also arise from the appended claims or from a combination of several of these claims. Example

[0365] The invention is described in detail below with reference to the following non-limiting embodiments.

[0366] Compound Examples

[0367] Compound Example 1: Synthesis of UUQU-4-N

[0368]

[0369] Step 1.1

[0370]

[0371] 20.3 mL (203 mmol) of 1,3-propanedithiol was dissolved in 25.9 mL of toluene and the solution was heated to 80 °C. A solution of 34.5 g (135.1 mmol) of 3,000 mL of trifluoromethanesulfonic acid and 40 mL of toluene was prepared and added dropwise to the dithiol solution at 80 °C. After the addition was complete, the mixture was stirred at 80 °C for 45 minutes and then cooled to 20 °C. During the 80-minute period, 17.7 mL (200 mmol) of trifluoromethanesulfonic acid was added dropwise while maintaining the temperature below 25 °C. Toluene was distilled off at 80 °C and 40 mbar. An additional 25 mL of toluene was added, and all volatiles were distilled off again. The crystalline residue was used in the next step without further purification.

[0372] Step 1.2

[0373]

[0374] 93.1 g (0.6 mol) of salt 5 was suspended in 1.6 L of dichloromethane and cooled to 6 °C. 83.2 mL (0.6 mol) of triethylamine was added dropwise at 5 °C, followed by 230 g (0.5 mol) of salt 4. The mixture was stirred at 5 °C for 30 minutes, then cooled to -75 °C and 244.3 mL (1.5 mol) of triethylamine trihydrofluoride was added dropwise. The solution was stirred at -75 °C for one hour, and 128 mL (2.5 mol) of bromine dissolved in 400 mL of dichloromethane was added. The mixture was stirred at -70 °C for 1.5 hours and then heated to 0 °C. After conventional treatment, 132 g (62%) of salt 6 as light beige crystals was obtained.

[0375] Step 1.3

[0376]

[0377] 13.8 g (35 mmol) of 6 was dissolved in 150 mL of 1,4-dioxane, and 1.0 g (1.4 mmol) of palladium acetate, 10.4 g (0.1 mol) of potassium acetate, and 13.9 g (53 mmol) of bis(pinacol)boron were added. The mixture was heated under reflux overnight. After conventional treatment, 12.4 g (80%) of 7 as pale yellow crystals was obtained.

[0378] Step 1.4

[0379]

[0380] 5.4 g (23 mmol) of potassium phosphate was dissolved in 10 ml of water. 80 ml of toluene, 2.8 g (11.4 mmol) of 1-bromo-2,6-difluoro-4-butylbenzene 8, 6.3 g (14.2 mmol) of 7, 42.2 mg (0.2 mmol) of palladium acetate, and 126.7 mg (0.3 mmol) of S-Phos (2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl) were added, and the mixture was heated under reflux overnight. After conventional treatment, 3.42 g (62%) of 9 (UUQU-4-N) as colorless crystals were obtained.

[0381] 1 ¹H NMR (400MHz, chloroform-d) δ 7.16 (d, J = 11.0 Hz, 2H), 7.07–6.99 (m, 2H), 6.91–6.81 (m, 2H), 2.69–2.61 (m, 2H), 1.69–1.57 (m, 2H), 1.39 (h, J = 7.4 Hz, 2H), 0.96 (t, J = 7.3 Hz, 3H).

[0382] Molecular weight: 485.4.

[0383] Melting point: 44℃, clearing point: 21℃.

[0384] Extrapolated data from a 10% solution in ZLI-4792: Δn(20℃) = 0.120 and Δε(20℃) = 54.6.

[0385] Characterization of ferroelectric-nematic behavior:

[0386] Materials, compounds, and mixtures were observed under a polarizing microscope with a temperature-controlled hot stage. Their textures were observed and recorded in video. The unique LC texture characteristic of their ferroelectric nematic phases was confirmed.

[0387] Dielectric properties were also measured.

[0388] Table: Measurement of ε at different temperatures (cooling rate of 1℃ / min, non-oriented sample on metal surface, generating ε) av. )

[0389] <![CDATA[ T / ℃ ]]> <![CDATA[ ε av . (1kHz,T) ]]> Remark 5.0 2.34 Crystallization upon cooling 7.0 7,730 10.0 11,300 12.0 13,800 14.0 16,500 16.0 19,100 18.0 21,500 19.8 23,100 <![CDATA[ε max .]]> 20.0 22,800 20.5 2.39 <![CDATA[Convert N f -isotropic]]> 21.0 2.39 22.0 2.40

[0390] Compound Example 2: Synthesis of UUZU-4-N

[0391]

[0392] Step 2.1

[0393]

[0394] Step 2.2

[0395] Combine 57.2 g (150 mmol) disodium tetraborate decahydrate, 2.8 g (4 mmol) palladium chloride, 0.2 g (4 mmol) hydrazine hydroxide, 39.4 g (0.2 mol) 1-bromo-3,5-difluorobenzene, 42.8 g (0.2 mol) 10, and 200 ml of water. Heat the mixture to reflux for 6 hours. After conventional treatment, 50 g (88%) of 11 was obtained.

[0396]

[0397] Step 2.3

[0398] 50 g (175 mmol) of 11 was dissolved in 300 ml of tetrahydrofuran and cooled to -75 °C. 118 ml (193 mmol) of a 15% n-butyllithium solution in hexane was added dropwise at -70 °C while the mixture was stirred at this temperature for 1.5 hours. The mixture was poured over 500 g of solid carbon dioxide and allowed to warm to room temperature. After conventional treatment, 46.8 g (82%) of 12 as colorless crystals was obtained.

[0399]

[0400] Step 2.4

[0401] 16.3 g (50 mmol) of 12, 8.5 g (55 mmol) of 1-cyano-2,6-difluoro-4-hydroxybenzene, and 611 mg (5 mmol) of 4-dimethylaminopyridine were mixed with 200 mL of dichloromethane and cooled to 0 °C. A solution of 11.3 g (55 mmol) of N,N-dicyclohexylcarbodiimide in 50 mL of dichloromethane was added dropwise between 0 and 5 °C. The mixture was then heated to room temperature and stirred overnight. 1.4 g of oxalic acid was added, and all substances were stirred for another 1.5 hours. After standard treatment, 20.5 g (88%) of 13 (UUZU-4-N) was obtained.

[0402] 1 ¹H NMR (500MHz, chloroform-d) δ 7.23–7.17 (m, 2H), 7.15–7.08 (m, 2H), 6.91–6.83 (m, 2H), 2.69–2.62 (m, 2H), 1.69–1.59 (m, 2H), 1.39 (h, J = 7.4 Hz, 2H), 0.96 (t, J = 7.4 Hz, 3H).

[0403] Phase: C 69N f / N 93I.

[0404] Extrapolated data from a 10% solution in ZLI-4792: Δn(20℃) = 0.159 and Δε(20℃) = 70.3.

[0405] Compound Example 3: Synthesis of UUZU-5-N

[0406]

[0407] The preparation of this compound is similar to that in Example 2.

[0408] Melting point: 80℃.

[0409] Extrapolated data from a 10% solution in ZLI-4792: Δn(20℃) = 0.162 and Δε(20℃) = 80.5.

[0410] Similar to Examples 1 and 2, the following compounds were prepared:

[0411] In the table below, the following abbreviations for end bases are used.

[0412]

[0413] General structure:

[0414]

[0415] Table. Examples of other compounds

[0416]

[0417]

[0418]

[0419] Mp: Melting point

[0420] The embodiments of the present invention and other combinations of the variations thereof are also disclosed in the claims.

[0421] Without further detailed description, it is believed that those skilled in the art can utilize the invention to its fullest extent using the foregoing description. Therefore, the foregoing preferred embodiments should be interpreted as illustrative only and in no way limit the remainder of the invention. The foregoing embodiments can be similarly and successfully replicated by replacing the reactants and / or operating conditions used in the foregoing embodiments with those generally or specifically described in the invention.

[0422] Based on the foregoing description, those skilled in the art can readily determine the basic features of the present invention, and various changes and modifications can be made to the present invention to adapt it to various uses and conditions without departing from the spirit and scope of the present invention.

[0423] This applies to a medium being a composition having its components, which may be a group of compounds and individual compounds, and it applies to a group of compounds having its individual components (i.e., compounds). The term includes, only with respect to the concentration of the individual compounds relative to the medium as a whole, the meaning that the concentration of one or more compounds under discussion is preferably 1% or higher, particularly preferably 2% or higher, and very particularly preferably 4% or higher.

[0424] In this invention, "≤" means less than or equal to, preferably less than, and "≥" means greater than or equal to, preferably greater than.

[0425] For the present invention,

[0426] and

[0427] This indicates the trans-1,4-cyclohexyl group.

[0428]

[0429] This indicates a mixture of cis-1,4-cyclohexylene and trans-1,4-cyclohexylene, and

[0430] as well as

[0431] It represents 1,4-phenylene.

[0432] For the purposes of this invention, the term "dielectrically positive compound" refers to a compound having Δε > 1.5, the term "dielectrically neutral compound" refers to a compound having -1.5 ≤ Δε ≤ 1.5, and the term "dielectrically negative compound" refers to a compound having Δε < -1.5. Here, the dielectric anisotropy of the compound is determined by dissolving 10% of the compound in a liquid crystal matrix and, in each case, measuring the capacitance of the resulting mixture in at least one test cell with a cell thickness of 20 μm and a vertical and uniform surface alignment at 1 kHz. The measurement voltage is typically 0.5 V to 1.0 V, but always below the capacitance threshold of the individual liquid crystal mixtures (materials) studied.

[0433] The host mixtures for the dielectric positive and dielectric neutral compounds were ZLI-4792, and the host mixture for the dielectric negative compounds was ZLI-2857, both sourced from Merck KGaA, Germany. The values ​​for each compound under study were obtained by extrapolating the change in dielectric constant of the host mixture after adding the compound under study to 100% of the total compound used. The compound under study was dissolved in the host mixture at 10%. If the solubility of a substance was too low for this purpose, the concentration was halved in the steps until the study could be carried out at the desired temperature.

[0434] If necessary, the liquid crystal medium according to the invention may also contain other additives, such as stabilizers in commonly used amounts. The amount of these additives used, based on the total amount of the mixture, is preferably 0% or more to 10% or less, particularly preferably 0.1% or more to 6% or less. The concentration of each compound used is preferably 0.1% or more to 3% or less. The concentrations of these and similar additives are generally not considered when specifying the concentrations and concentration ranges of the liquid crystal compounds in the liquid crystal medium.

[0435] For the purposes of this invention, unless otherwise expressly stated, all concentrations are indicated as a weight percentage, and unless otherwise expressly stated, all concentrations relate to the corresponding mixture or mixture components (again, as a whole). In this context, the term "mixture" describes the liquid crystal medium.

[0436] Unless otherwise explicitly instructed, use the following symbols:

[0437] T(N,I) or T(N) f (I) (or clp.) Clear the light [°C],

[0438] Dielectric properties at 1 kHz and preferably at 20 °C, or at various specified temperatures:

[0439] ε ┴ Dielectric susceptibility perpendicular to the direction vector,

[0440] ε || Dielectric polarizability parallel to the director,

[0441] Δε dielectric anisotropy, and screening data, especially for single compounds, and

[0442] ε av. Average dielectric polarization.

[0443] Furthermore, particularly regarding the data obtained from screening individual compounds in the nematic host mixture ZLI-4792:

[0444] n e Unusual refractive index measured at 20°C and 589 nm

[0445] n o Ordinary refractive index measured at 20℃ and 589nm and

[0446] Optical anisotropy of Δn measured at 20℃ and 589nm.

[0447] The following examples illustrate the invention, but are not intended to limit it. However, they demonstrate to those skilled in the art the concept of preferred mixtures utilizing preferably employed compounds, their respective concentrations, and combinations thereof. Furthermore, the examples illustrate the achievable properties and combinations thereof.

[0448] Table A: Ring Elements

[0449]

[0450]

[0451]

[0452] Table B: Bridging Units

[0453]

[0454] Table C: End bases

[0455]

[0456]

[0457]

[0458] Where n and m are each integers (1, 2, 3, 4, 5, 6, 7, etc.), and the three dots “…” are placeholders for other abbreviations used in this table.

[0459] In addition to compounds of formula IA and / or formula IB and / or formula IC, the mixtures according to the invention preferably contain one or more compounds mentioned below.

[0460] Use the following abbreviations:

[0461] (n, m, k, and l are each independent integers, preferably 1 to 9, more 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, and in the combination "-nO-", it is preferably 1, 2, 3, or 4, more preferably 2 or 4; m is preferably 1, 2, 3, 4, or 5, and in the combination "-Om", it is preferably 1, 2, 3, or 4, more preferably 2 or 4. The combination "-lVm" is preferably "2V1".)

[0462] For the purposes of this invention and in the following embodiments, the structure of the liquid crystal compound is indicated by acronym and the chemical formulas are converted 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 2lAll are straight-chain alkyl or alkylene groups, each having n, m, and l C atoms. Preferably, n, m, and l are independently 1, 2, 3, 4, 5, 6, or 7. Table A shows the coding 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. Acronyms consist of the following: the coding of the ring element with an optional linking group, followed by the first hyphen and the coding of the left end group, and the second hyphen and the coding of the right end group. Table D shows the illustrative structure of the compound and its various abbreviations.

[0463] Table D

[0464] Exemplary preferred compound of formula IA

[0465]

[0466]

[0467] Exemplary preferred formula IB compounds

[0468]

[0469]

[0470] Exemplary preferred IC compounds

[0471]

[0472]

[0473] Other preferred compounds

[0474]

[0475]

[0476]

[0477]

[0478]

[0479]

[0480]

[0481] PGP-n-lVm

[0482] Where n, m, l are 1, 2, 3, 4, 5, 6, 7, etc., and n can also be 0.

[0483] Mixture Examples

[0484] The following discloses exemplary mixtures.

[0485] Mixture Example 1

[0486] The following mixture (M-1) was prepared and studied.

[0487]

[0488] Remark:

[0489] c The value during cooling.

[0490] h The value when heated.

[0491] Upon cooling, this mixture M-1 exhibits a ferroelectric nematic phase decreasing from 40°C to 5°C. This phase is monovariant, meaning it can be supercooled. Upon heating, this phase reappears at approximately 35°C and then transforms again into different intermediate phases at approximately 45°C. The phases were confirmed by microscopic examination and DSC. This mixture exhibits extremely high dielectric permittivity at these temperatures.

[0492] Hysteresis in the dielectric constant was observed at higher temperatures. At approximately 60°C, a conventional nematic phase appeared.

[0493] Mixture Example 2

[0494] The following mixture (M-2) was prepared and studied.

[0495]

[0496] This mixture M-2 exhibits a ferroelectric nematic phase. This ferroelectric nematic extends from 30°C to 25°C upon cooling.

[0497] Mixture Example 3

[0498] The following mixture (M-3) was prepared and studied.

[0499]

[0500] This mixture M-3 exhibits a ferroelectric nematic phase. This phase extends from 46°C to 25°C upon cooling. (Mixture Example 4)

[0501] The following mixture (M-4) was prepared and studied.

[0502]

[0503] This mixture M-4 exhibits a ferroelectric nematic phase. This phase extends from 77°C to 31°C upon cooling.

[0504] Mixture Example 5

[0505] The following mixture (M-5) was prepared and studied.

[0506]

[0507] This mixture M-5 exhibits a ferroelectric nematic phase below 62°C. This phase is metastable at 20°C upon cooling.

[0508] Mixture Example 6

[0509] The following mixture (M-6) was prepared and studied.

[0510]

[0511] This mixture M-6 exhibits a ferroelectric nematic phase below 49°C.

[0512] Mixture Example 7

[0513] The following mixture (M-7) was prepared and studied.

[0514]

[0515]

[0516] This mixture, M-7, exhibits a ferroelectric nematic phase. This phase is metastable at 20°C upon cooling.

[0517] Mixture Example 8

[0518] The following mixture (M-8) was prepared and studied.

[0519]

[0520] This mixture M-8 exhibits a stable ferroelectric nematic phase below 48°C.

[0521] Mixture Example 9

[0522] The following mixture (M-9) was prepared and studied.

[0523]

[0524] As with the aforementioned mixtures, this mixture M-9 exhibits a ferroelectric nematic phase at ambient temperature.

[0525] Mixture Example 10

[0526] The following mixture (M-10) was prepared and studied.

[0527]

[0528]

[0529] This mixture M-10 exhibits a ferroelectric nematic phase below 59°C.

[0530] Mixture Example 11

[0531] The following mixture (M-11) was prepared and studied.

[0532]

[0533] This mixture M-11 exhibits a ferroelectric nematic phase. This phase extends from at least 19°C to 36°C.

[0534] Mixture Example 12

[0535] The following mixture (M-11) was prepared and studied.

[0536]

[0537]

[0538] This mixture M-12 exhibits a ferroelectric nematic phase. This phase extends from at least 60°C to 73°C upon heating and from 73°C to 10°C upon cooling.

Claims

1. A liquid-crystalline medium which exhibits a ferroelectric nematic phase at 20°C, wherein the medium comprises 50% to 100% of compounds of formula IA and / or of formula IB and / or of formula IC, wherein X 1A , X 1B and X 1C independently of one another represent -F, -OCF3, -Cl, -NCS or -CN, Z 1A , Z 1B and Z 1C independently of one another represent -(C=0)-0- or -CF2-0-, L 1A , L 1B and L 1C independently of one another denote H or CH3, 2. A liquid-crystalline medium which comprises two, three or more compounds selected from the group of compounds of formula IA, of formula IB and of formula IC, wherein X 1A , X 1B and X 1C independently of one another represent -F, -OCF3, -Cl, -NCS or -CN, Z 1A , Z 1B and Z 1C independently of one another represent -(C=0)-0- or -CF2-0-, L 1A , L 1B and L 1C independently of one another denote H or CH3, wherein the concentration of the group of compounds of formula IA, of formula IB and of formula IC is 90% by weight or more, wherein the liquid-crystalline medium comprises compounds selected from two or all three of formula IA, of formula IB and of formula IC.

3. The liquid-crystalline medium according to claim 2, which exhibits a ferroelectric nematic phase.

4. The liquid-crystalline medium according to any one of claims 1 to 3, which comprises one, two, three or more compounds of formula IA as defined in claim 2.

5. The liquid-crystalline medium according to any one of claims 1 to 3, which comprises one, two, three or more compounds of formula IB as defined in claim 2.

6. The liquid-crystalline medium according to any one of claims 1 to 3, which comprises one, two, three or more compounds of formula IC as defined in claim 2.

7. The liquid-crystalline medium according to any one of claims 1 to 3, which comprises 40% by weight or more of one or more compounds of formula IA.

8. The liquid-crystalline medium according to any one of claims 1 to 3, which exhibits a ferroelectric nematic phase at least in the temperature range from 0°C to 40°C.

9. The liquid-crystalline medium according to any one of claims 1 to 3, which exhibits a dielectric anisotropy of 400 or more at 20°C and 1 kHz.

10. The liquid-crystalline medium according to any one of claims 1 to 3, which exhibits hysteresis in its dielectric properties.

11. The liquid-crystalline medium according to any of claims 1 to 3, comprising one or more compounds of formula IA, wherein the right-hand group X 1A represents CN.

12. Use of a liquid-crystalline medium according to any one of claims 1 to 11 for providing a ferroelectric nematic liquid-crystalline material.

13. Use of a liquid-crystalline medium according to any one of claims 1 to 12 for energy-saving displays or appliances.

14. An electro-optical liquid-crystalline display comprising a liquid-crystalline medium according to any one of claims 1 to 11.

15. A process for the preparation of a liquid-crystalline medium according to any one of claims 2 to 11, which one or more compounds selected from the group of compounds of formula IA, of formula IB and of formula IC as given in claim 2 are mixed with each other or with one or more further compounds.

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