Liquid crystal media and electro-optical devices

Abstract

A liquid crystal medium and an electro-optical device are provided. The novel media preferably exhibit a ferroelectric nematic phase at ambient temperature. They comprise one or more compounds selected from the group of compounds of formulas IA, IB, and IC, where the variables have the meanings indicated in the description and claims. Use of the media to provide ferroelectric nematic materials and methods for operating electro-optical devices is presented. The media may be useful for energy-saving displays and electrical applications. TIFF2023551934000115.tif133166

Description

[Technical Field]

[0001] An embodiment of the present invention relates to liquid-crystalline media which exhibit a ferroelectric nematic liquid-crystalline phase in a substantial temperature range, preferably at ambient temperature. These media preferably contain one or more compounds selected from the group of compounds of formulae IA, IB and IC as defined below, which maintain a ferroelectric nematic liquid-crystalline phase. In addition, the present invention relates to liquid-crystalline displays and electro-optical elements which contain the liquid-crystalline media according to the invention, as well as to a method for operating an electro-optical device. [Background technology]

[0002] In recent years, the application fields of liquid crystal compounds have expanded significantly to various types of display devices, electro-optical devices, electronic components, sensors, etc. For this reason, particularly in the field of nematic liquid crystals, a large number of different structures have been proposed. Nematic liquid crystals have found the most widespread use to date in flat panel display devices. They have been employed in particular in passive TN or STN matrix displays or systems with TFT active matrices (including the well-known TN, IPS, FFS, and VA systems).

[0003] Most of these devices, including all common LCD television sets, LCD desktop monitors, and mobile LCD devices, employ a nematic liquid crystal phase. Several alternative liquid crystal phases are known, such as the ferroelectric smectic phase or blue phase. However, the ferroelectric nematic phase (N f Ferroelectric nematic (FER) phases have been postulated theoretically for decades, despite the lack of suitable liquid crystal materials with such properties. Recently, two chemical structures have been reported that show signs of ferroelectric nematic behavior.

[0004] Hiroya Nishikawa, Kazuya Shiroshita, Hiroki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin-ichi Yamamoto, Koki Sago and Hirotsugu Kikuchi, Adv. Mater. (2017), Vol. 29, p. 1702354 (Non-Patent Document 1), describes a compound of formula A that exhibits ferroelectric nematic behavior at temperatures between about 45°C and 68°C.

[0005] [ka]

[0006] Furthermore, Nerea Sebastian, Luka Cmok, Richard J. Mandle, Maria Rosario de la Fuente, Irena Drevensek Olenik, Martin Copic and Alenka Mertelj, Physical Review Letters (2020), Vol. 124, p. 037801 (Non-Patent Document 2), describe a compound of formula B that has similar behavior at temperatures between about 120 ° C. and 133 ° C.

[0007] [ka]

[0008] Furthermore, N f A comparison of the only two materials available for LC phases is presented in Xi Chen et al., PNAS (June 23, 2020), Vol. 117 (No. 25), pp. 14021-14031 (Non-Patent Document 3). O.D. Lavrentovich, Proc Nat Acad Sci USA (2020), Vol. 117 (No. 26), pp. 14629-14631 (Non-Patent Document 4), presents a new N f The significance of the N-LC phase has been emphasized. f The observed temperature of the phase is well above ambient temperature.

[0009] Until now, the ferroelectric nematic liquid crystal phase (N f -LC phase) were not described. Ambient temperature, which may also be referred to as room temperature, is intended herein to mean a temperature of 20°C.

[0010] N for technical applications f Developing a -LC phase has obvious advantages in terms of applicability to ambient temperatures: display applications are typically designed to have a wide operating range above and below ambient temperature, e.g., 15°C to 25°C, preferably 0°C to 50°C, and preferably even wider than ambient temperature.

[0011] A ferroelectric nematic display has been proposed in DE 19629551 A1, but no specific materials capable of fulfilling the required ferroelectric nematic properties are disclosed.

[0012] The use of fluorinated liquid crystal materials 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, for example, in WO 2015 / 101405 (Patent Document 2) and WO 2005 / 019381 (Patent Document 3), and further in various other publications. The compounds proposed therein have been fully characterized, but have not been reported to have any ferroelectric properties. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] German Patent Application Publication No. 19629551 [Patent Document 2] International Publication No. 2015 / 101405 [Patent Document 3] International Publication No. 2005 / 019381 [Non-patent literature]

[0014] [Non-Patent Document 1] Hiroya Nishikawa, Kazuya Shiroshita, Hiroki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin-ichi Yamamoto, Koki Sago and Hirotsugu Kikuchi, Adv. Mater. (2017), Vol. 29, pp. 1702354 [Non-patent document 2] Nerea Sebastian, Luka Cmok, Richard J. Mandle, Maria Rosario de la Fuente, Irena Drevensek Olenik, Martin Copic and Alenka Mertelj, Physical Review Letters (2020), Volume 124, Page 037801 [Non-patent document 3] Xi Chen et al., PNAS (June 23, 2020), Volume 117 (No. 25), Pages 14021-14031 [Non-patent document 4] ODLavrentovich, Proc Nat Acad Sci USA (2020), Volume 117 (No. 26), Pages 14629-14631 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0015] The object of the present invention is to provide a ferroelectric nematic liquid crystal phase medium (N f The objective of the present invention is to find novel and stable compounds and materials suitable as N-LC phase media. f -LC phase, N f -LC media, they must maintain such a phase. They must also have moderate to high optical anisotropy to achieve electro-optical switching effects similar to conventional nematic LC media.

[0016] In view of the very diverse fields of application of compounds of this type having high dielectric anisotropy (Δε), it was desirable to have further available compounds which exhibit a wide suitable temperature range of the ferroelectric nematic phase, while preferably having a high clearing point and a low melting point.

[0017] It was therefore a further object of the present invention to find novel stable compounds as component(s) of ferroelectric nematic liquid crystal media, in particular for displays similar to conventional nematic TN, STN, IPS, FFS and TN-TFT displays.

[0018] In addition, it was an aim for the compounds according to the invention to be thermally and photochemically stable under the conditions prevailing in the field of application. As mesogens, they must promote a broad mesogenic phase, preferably a nematic phase in mixtures with liquid crystal co-components, especially at low temperatures, at least below room temperature, and be readily miscible with mesogenic, preferably nematic, base mixtures. [Means for solving the problem]

[0019] Surprisingly, the disclosed compounds are fIt has been found that the compounds are highly suitable as components of LCD media. They can be used to obtain liquid-crystalline media for displays requiring particularly high or even very high dielectric anisotropy, in particular for IPS or FFS displays, but also for TN or STN displays. The media used according to the invention are sufficiently stable and colorless. In particular, they are distinguished by very high dielectric constants, in particular very high dielectric anisotropy (Δε). Thanks to the high dielectric anisotropy, for example, much lower threshold voltages are required when used in optical switching elements. The compounds have reasonably good solubility for compounds with comparable properties and are almost unlimitedly miscible with similar compounds. In addition, the compounds used according to the invention have high clearing points. These compounds also have relatively low melting points or can be stably maintained below their melting point as supercooled melts, which means that the desired N-type condensation can be achieved at even lower temperatures, for example below room temperature. f -Facilitates the formation of LC phases.

[0020] The provision of the compounds and mixtures according to the invention very generally significantly widens the range of liquid crystal substances which are suitable from various application points of view for the preparation of ferroelectric nematic liquid crystal mixtures.

[0021] The compounds used according to the present invention have a wide range of applications.Depending on the selection of substituents, these compounds can function as the base material that liquid crystal medium is mainly composed of.But it is also possible to convert the liquid crystal base material from other classes of compounds into this compound, for example, to further reduce melting point, to affect the dielectric properties and / or optical anisotropy of this type of dielectric, and / or to optimize its threshold voltage and / or viscosity.

[0022] N fThe use of LC phases allows for LC media with extremely short response times compared to conventional nematic LC systems currently used in standard displays. This allows for a substantial improvement in the means of displaying moving images. The high dielectric constant also makes the media interesting as a capacitor dielectric. The media's outstanding dielectric properties make it useful for energy-saving displays and other electrical applications. Lower voltages are required compared to the prior art.

[0023] The liquid-crystalline compounds can be used as component(s) of liquid-crystalline media for displays based in particular on the twist cell principle, the guest-host effect, the deformation effect of the alignment phase DAP or ECB (electrically controlled birefringence), the IPS (in-plane switching) effect or the dynamic scattering effect. [Brief explanation of the drawings]

[0024] [Figure 1] Figure 1 shows a graph depicting the dielectric properties of Mixture Example 5 over the temperature range of 20-105°C. The T / εr graph, measured at 10 Hz and a voltage of approximately 50 mV, shows the values ​​of the relative permittivity εr upon cooling (solid line) and heating (dashed line) at different temperatures T. The εr value has a maximum value (plateau shape) between approximately 20-60°C and then decreases rapidly towards higher temperatures. The maximum permittivity value of εr is approximately 4·103. DETAILED DESCRIPTION OF THE INVENTION

[0025] In one main aspect, the invention relates to a liquid-crystalline medium comprising one, two or more compounds selected from the group of compounds of the formulae IA, IB and IC.

[0026] [ka]

[0027] During the ceremony X 1A, X 1B and X 1C each independently represent CN, F, CF, -OCF, SCN, NCS, SF or O-CF=CF, preferably -CN, F, -CF, -OCF, -Cl or -NCS, most preferably F or CN; Z 1A , Z 1B and Z 1C each independently represents -(C=O)-O- or -CF2-O-; [ka] represents [ka] represents [ka] represents L 1A , L 1B and L 1C each independently represents H or CH3, preferably H, R 1A , R 1B and R 1C are each independently 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 (provided that in addition, one or more CH groups in these groups may in each case be independently -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -C≡C ... [ka] -O-, -S-, -CO-O- or -O-CO-, provided that in addition one or more H atoms may be replaced by halogen; Preferably R 1A , R 1B and R 1Care each halogenated or unsubstituted alkyl groups having 1 to 15 C atoms, provided that in addition, one or more CH groups in these groups may in each case independently be replaced by -C≡C- or -CH=CH-.

[0028] The invention further relates to the use of compounds of the formulae IA, IB and IC in liquid-crystalline media, preferably in ferroelectric nematic media.

[0029] The invention likewise relates to a liquid-crystalline medium comprising at least one compound of the formula I (IA, IB, IC) and optionally any additive.

[0030] A further aspect of the present invention is the use of a liquid crystal medium to provide a ferroelectric nematic liquid crystal material.

[0031] In the pure state, the compounds of formulae IA, IB and IC are colorless and, by themselves or in mixtures, form liquid crystal mesophases within a temperature range that is advantageous for electro-optical use. The compounds according to the invention allow a wide ferroelectric nematic phase range to be achieved. They also have the N f The compounds of formulas IA, IB and IC used in the liquid crystal mixture according to the present invention significantly increase the optical anisotropy.At the same time, these compounds are distinguished by sufficiently good UV stability.

[0032] The group R in each of the formulae IA, IB and IC and their respective sub-formulae 1A , R 1B and R 1C preferably represents alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms or alkenyl having 2 to 8 carbon atoms. These alkyl chains are preferably linear or they are preferably 1C In the case of R, it is preferably branched with a single methyl or ethyl substituent at the 2- or 3-position. 1A , R 1B and R1C particularly preferably denotes a linear alkyl group having 1 to 7 C atoms or an unbranched alkenyl group having 2 to 8 C atoms, in particular an unbranched alkyl group having 1 to 5 C atoms.

[0033] Alternatively 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-alkyloxyethoxy.

[0034] Alternatively, the group R 1A , R 1B and R 1C represents H or alkyl having 1 to 5 C atoms.

[0035] Group X of each of formulae IA, IB and IC 1A , X 1B and X 1C preferably represents CN, F or CF, preferably CN or F, most preferably especially X 1C represents CN.

[0036] Branched or substituted end groups R 1A , R 1B and R 1C Compounds of formula IA, IB and IC, respectively, containing the group R may be important for better solubility in conventional liquid crystal base materials. 1A , R 1B and R 1C are each preferably linear and unbranched.

[0037] base R 1A , R 1B and R 1C are each particularly preferably selected from the lower moiety.

[0038] [ka]

[0039] However, the following abbreviations are used for the end groups:

[0040] [ka]

[0041] In a preferred embodiment, the medium according to the invention preferably comprises one, two or more compounds of formula IA, preferably selected from the group of formulae IA-1 to IA-3, preferably of formula IA-1 or IA-2, most preferably of formula IA-2.

[0042] [ka]

[0043] [ka]

[0044] where the parameters have the respective meanings given above, preferably Z 1A represents -CF2-O-, X 1A represents -CN or F, preferably -CN, and in particular in formula IA-2 preferably alternatively X 1A represents F.

[0045] The mixture preferably contains 40% by weight or more, more preferably 45% by weight or more, more preferably 50% by weight or more of a compound of formula IA.

[0046] In a preferred embodiment, the medium according to the invention preferably comprises one, two or more compounds of formula IB, preferably selected from the group of formula IB-1 and IB-2, preferably formula IB-2.

[0047] [ka]

[0048] [ka]

[0049] where the parameters have the respective meanings given above, preferably Z 1B represents -CF2-O-, and X 1B represents -CN, and in particular in formula IB-2 preferably alternatively Z 1B represents -(C=O)-O-, and X 1A represents F.

[0050] In a preferred embodiment, the medium according to the invention preferably comprises one, two or more compounds of formula IC, preferably selected from the group of formulae IC-1 to IC-4, more preferably selected from the group of formulae IC-2 and IC-3, most preferably selected from the group of formula IC-3.

[0051] [ka]

[0052] [ka]

[0053] where the parameters have the respective meanings given above, preferably Z 1C represents -(C=O)-O-, and X 1C represents -CN, and in particular in formula IC-2 preferably alternatively Z1C represents -CF2-O-, and X 1C represents F.

[0054] Particularly preferred compounds of formula IC to be used in the medium are compounds of formulae IC-3.1 to IC-3.20:

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] [ka]

[0059] and further compounds of formula IC-3.21 to IC-3.26.

[0060] [ka]

[0061] [ka]

[0062] Particularly preferred compounds of formula IC for use in the medium are those of the following formula:

[0063] [ka]

[0064] In a preferred embodiment of the invention, the medium comprises 15% by weight or more of one or more compounds of formula IA-3-N, and optionally preferably 5% by weight or more, more preferably 15% by weight or more of one or more compounds of formula IA-3-F, and optionally preferably 15% by weight or more, more preferably 20% by weight or more of one or more compounds of formula IC.

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] During the ceremony, X 13C represents -CN or -NCS, preferably -CN, X 1C represents -CN, F, CF3, -OCF3, -NCS, SF5 or O-CF=CF2, preferably -CN or F, most preferably CN, Z 1A represents -(CO)-O- or -CF2-O-; Z 1C is —(CO)—O— or —CF2—O—, L 1A and L 1C are in each case independently of one another H or CH3, preferably H, [ka] represents [ka] represents R 1A and R 1Care each independently an alkyl group having 1 to 12, preferably 1 to 8, more preferably 1 to 6, most preferably 1 to 5 C atoms (provided that in addition, one or more CH groups in these groups may in each case be independently -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -C≡C ... [ka] -O-, -S-, -(CO)-O- or -O-(CO)-, provided that in addition one or more H atoms may be replaced by halogen; Preferably R 1A , R 1B and R 1C are independently halogenated or unsubstituted alkyl groups having 1 to 10 C atoms, provided that in addition, one or more CH groups in these groups may be replaced by -O- or -CH=CH- in such a way that no O atom is directly connected.

[0069] In a preferred embodiment of the present invention, the medium comprises up to 100% of one or more compounds, preferably two or more compounds, selected from group 1 of compounds, the group of compounds of formulae IA, IB, and IC. In this embodiment, the medium preferably consists mainly of these compounds, more preferably they consist essentially of them, and most preferably they consist substantially completely of them. In this embodiment, the concentration of compounds of this group 1 of compounds is preferably in the range of 50% or more, preferably 60% or more to 100% or less.

[0070] For purposes of the present invention, unless otherwise indicated in particular cases, the following definitions apply in connection with the identification of the components of the compositions.

[0071] "Contains": The concentration of the component in question in the composition is preferably 5% or more, particularly preferably 10% or more, very particularly preferably 20% or more.

[0072] "Consists mainly of": The concentration of the component of interest in the composition is preferably 50% or more, particularly preferably 55% or more, very particularly preferably 60% or more.

[0073] "Consists essentially of": The concentration of the component in question in the composition is preferably 80% or more, particularly preferably 90% or more, very particularly preferably 95% or more.

[0074] "Consists essentially completely of": The concentration of the component of interest in the composition is preferably 98% or more, particularly preferably 99% or more, very particularly preferably 100.0%.

[0075] Preferably, the medium according to the present application satisfies one or more of the following conditions. They are preferably:

[0076] one, two or more compounds of formula IA,

[0077] 1, 2 or 3 or more types of X 1A a compound of formula IA wherein is F;

[0078] 1, 2 or 3 or more types of X 1A is CN, preferably at least 15% by weight, more preferably at least 25% by weight, most preferably at least 30% by weight of a compound of formula IA,

[0079] one, two or more compounds of formula IB,

[0080] one, two or more compounds of formula IC,

[0081] 1, 2 or 3 or more types of X 1C Preferably at least 35% by weight or more, more preferably 45% by weight or more, 55% by weight or more or 65% by weight or more of a compound of formula IC, wherein is CN,

[0082] 1, 2 or 3 or more types of X 1ACompounds of formula IA, wherein is CN, are prepared by reacting one, two or more compounds of X 1A In combination with a compound of formula IA where is F,

[0083] one, two or more compounds of formula IA-1, preferably of formula AUUQU-nN, most preferably selected from the group of compounds AUUQU-2-N, AUUQU-3-N, AUUQU-4-N and AUUQU-5-N, and / or

[0084] one, two or more compounds of formula IA-2, preferably of formula DUUQU-nN and / or DUUQU-nF, most preferably selected from the group of compounds 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

[0085] one, two or more compounds of formula IA-3, preferably of formula GUUQU-nN, more preferably of formula GUUQU-0-N, GUUQU-1-N, GUUQU-2-N, GUUQU-3-N, GUUQU-4-N or GUUQU-5-N, most preferably the compound GUUQU-3-N, and / or

[0086] one, two or more compounds of formula IA-3, of formula GUUQU-nF, most of the compounds GUUQU-2-N, GUUQU-3-N, GUUQU-4-N or GUUQU-5-N, and / or

[0087] one, two or more compounds of formula IB-2, preferably of formula GUQGU-nN, more preferably of formula GUQGU-3-N, and / or

[0088] one, two or more compounds of formula IC-2, preferably of formula MUZU-nF, most preferably compounds MUZU-4-F and / or MUZU-5-F, and / or

[0089] one, two or more compounds of formula IC-3, preferably of formula UUZU-nN and / or UUQU-nN, most preferably selected from the group of compounds UUZU-4-N, UUZU-5-N and UUQU-4-N, and further 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 Includes.

[0090] In a preferred embodiment of the invention, said compounds of formula IA, IB and IC are group 1 of compounds, group 1 of compounds.

[0091] In one embodiment of the present invention, the medium optionally, but preferably essentially, comprises one or more compounds selected from the following group of compounds:

[0092] Optionally, and preferably essentially either alternatively or additionally, one or more compounds, preferably two or more compounds selected from the group of compounds of formulae IA, IB and IC, i.e., other further compounds of group 1, group 2, compounds of formulae II and III, in a concentration of greater than 0% to 50%.

[0093] [ka]

[0094] During the ceremony, R 2 represents an alkyl group having 1 to 15 C atoms, preferably 1 to 7, more preferably 1 to 6, most preferably 1 to 5 C atoms (provided that in addition, one or more CH groups in these groups may in each case independently be -C≡C-, -CF-O-, -OCF-, -CH=CH-, -C≡C-, -CF≡ ... [ka] -O-, -S-, -CO-O- or -O-CO-, provided that in addition one or more H atoms may be replaced by halogen; preferably alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, or alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, preferably alkyl or alkenyl, [ka] represents L 21 and L 22 represents H or F, preferably L 21 represents F, 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, -OCF3, -O-CH2CF3, -O-CH=CH2, -O-CH=CF2 or -CF3, very preferably F, Cl, -O-CH=CF2 or -OCF3, m represents 0, 1, 2 or 3, preferably 1 or 2, particularly preferably 2, R 3 represents an alkyl group having 1 to 15 C atoms, preferably 1 to 7, more preferably 1 to 6, most preferably 1 to 5 C atoms (provided that in addition, one or more CH groups in these groups may in each case independently be -C≡C-, -CF-O-, -OCF-, -CH=CH-, -C≡C-, -CF≡ ... [ka] -O-, -S-, -CO-O- or -O-CO-, provided that in addition one or more H atoms may be replaced by halogen; preferably alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, preferably n-alkyl, cyclopropyl, cyclopentyl or alkenyl, [ka] and L 31 and L 32 are each independently H or F, preferably L 31 represents F, 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, -OCF3, -OCHF2, -O-CH2CF3, -O-CH=CF2, -O-CH=CH2 or -CF3, very preferably F, Cl, -O-CH=CF2, -OCHF2 or -OCF3, Z 3 represents -CH2CH2-, -CF2CF2-, -(CO)O-, trans-CH=CH-, trans-CF=CF-, -CHO- or a single bond, preferably -CH2CH2-, -(CO)O-, trans-CH=CH- or a single bond, very preferably -(CO)O-, trans-CH=CH- or a single bond, n is 0, 1, 2 or 3, preferably 1, 2 or 3, particularly preferably 1, provided that each ring, preferably the phenylene ring, may be optionally substituted with one or two alkyl groups, preferably methyl and / or ethyl groups, preferably one methyl group, and However, especially [ka] may be replaced by and in particular, [ka] may be replaced by and with the proviso that compounds of formula IA, IB and IC are excluded from compounds of formula II.

[0095] Again optionally, and preferably essentially either alternatively or additionally, one or more compounds, preferably two or more compounds, selected from the group of compounds of Group 3, Formulas IV and V, preferably at a concentration of greater than 0% to 20%, preferably 10% or less.

[0096] [ka]

[0097] During the ceremony, R 41 and R 42 are independently an alkyl group having 1 to 15 C atoms, preferably 1 to 7, more preferably 1 to 6, most preferably 1 to 5 C atoms (provided that in addition, one or more CH groups in these groups may be independently -C≡C-, -CF-O-, -OCF-, -CH=CH-, -C≡C-, -CF≡ ...C≡C-, -C≡C-, -C≡C-, -C≡C-, -C≡C-, [ka] -O-, -S-, -CO-O- or -O-CO-, provided that in addition one or more H atoms may be replaced by halogen; Preferably, in formula II, R 2 has the meaning given above for R 41 represents alkyl, and R 42 represents alkyl or alkoxy, or R 41 represents alkenyl, and R 42 represents alkyl, [ka] represents Preferably [ka] represents Z 41 and Z 42 are independent of each other, and Z 41 when appearing twice, they also independently represent -CH2CH2-, -(CO)O-, trans-CH=CH-, trans-CF=CF-, -CHO-, -CF2O-, -C≡C- or a single bond, preferably one or more of them represents a single bond; p represents 0, 1 or 2, preferably 0 or 1, and R 51 and R 52 are, independently of each other, R 41 and R 42 has one of the meanings given for, 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 having 2 to 7 C atoms, preferably having 2 to 4 C atoms, alkenyl or alkenyloxy, preferably alkenyloxy, [ka] Preferably [ka] represents Preferably [ka] represents and if present, preferably [ka] represents Z 51 ~Z 53are each independently -CH-CH-, -CH-O-, -CH=CH-, -C≡C-, -(CO)O- or a single bond, preferably -CH-CH-, -CH-O- or a single bond, particularly preferably a single bond, i and j each independently represent 0 or 1; (i+j) preferably represents 0, 1 or 2, more preferably 0 or 1, most preferably 1; However, each ring, preferably the phenylene ring, may be optionally substituted with one or two alkyl groups, preferably methyl and / or ethyl groups, preferably one methyl group.

[0098] Again optionally and preferably essentially, either alternatively or additionally, one or more compounds, preferably two or more compounds, selected from the group of compounds of formulae I and VI to IX, group 4, preferably at a concentration of greater than 0% to 20%.

[0099] [ka]

[0100] During the ceremony, TIFF0007799692000045.tif248151, [ka] Preferably [ka] represents n represents 0 or 1, R 11 and R 12each independently preferably represents an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms (wherein one CH group may be replaced by a 1,2-cyclopropyl, 1,3-cyclopentyl or 1,3-cyclopentenylene group), an alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, preferably an alkyl, alkoxy, alkenyl or alkenyloxy, most preferably an alkyl, alkoxy or alkenyloxy, R 61 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a linear alkyl group, more preferably an n-alkyl group, most preferably propyl or pentyl, an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a linear alkenyl group, particularly preferably an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyloxy group having 2 to 6 C atoms, 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, l represents 0 or 1; R 71 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a linear alkyl group, more preferably an n-alkyl group, most preferably propyl or pentyl, an unsubstituted alkenyl group having 2 to 7 C atoms, preferably a linear alkenyl group, particularly preferably having 2 to 5 C atoms, R 72 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms, preferably 1, 2, 3 or 4 C atoms, or an unsubstituted alkenyloxy group having 2 to 6 C atoms, preferably 2, 3 or 4 C atoms, [ka] represents R 81 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably a linear alkyl group, more preferably an n-alkyl group, most preferably propyl or pentyl, or an alkenyl group having 2 to 7 C atoms, preferably a linear alkenyl group, particularly preferably having 2 to 5 C atoms, R 82 represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms, preferably 1, 2, 3 or 4 C atoms, or an unsubstituted alkenyloxy group having 2 to 6 C atoms, preferably 2, 3 or 4 C atoms, [ka] Z 8 represents -(C=O)-O-, -CH2-O-, -CF2-O- or -CH2-CH2-, preferably -(C=O)-O- or -CH2-O-, o represents 0 or 1, R 91 and R 92 are, independently of each other, 72 has the meaning given to R 91 preferably denotes an alkyl group having 2 to 5 C atoms, preferably having 3 to 5 C atoms, 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, [ka] p and q each independently represent 0 or 1; (p+q) preferably represents 0 or 1, [ka] Alternatively, preferably, p=q=1, provided that each ring, preferably the phenylene ring, may be optionally substituted with one or two alkyl groups, preferably methyl and / or ethyl groups, preferably one methyl group; and, but especially [ka] is replaced by and with the proviso that compounds of formula VIII are excluded from compounds of formula X, and compounds of formula VI are excluded from compounds of formulas VII-X.

[0101] Again optionally and preferably essentially, either alternatively or additionally, one or more compounds, preferably two or more compounds selected from the group of compounds of formula B, group 5, preferably at a concentration of greater than 0% to 20%.

[0102] [ka]

[0103] During the ceremony [ka] [ka] represents n represents 1 or 2, preferably 1; R 1represents an alkyl group having 1 to 7 C atoms (wherein one or more CH groups, preferably one CH group, may each independently be replaced by -C≡C-, -CF2-O-, -OCF2-, -O-, -(CO)-O-, -O-(C=O)-, cyclopropylene, 1,3-cyclobutylene, 1,3-cyclopentylene, 1,3-cyclopentenylene, preferably by cyclopropylene or 1,3-cyclopentylene, and preferably one CH group is replaced by a 1,2-cyclopropylene group, a 1,3-cyclopentylene group or a 1,3-cyclopentenylene group); alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, preferably alkyl or alkenyl (with the proviso that one -CH2- group may be replaced by cyclopropylene, 1,3-cyclobutylene, 1,3-cyclopentylene, 1,3-cyclopentenylene, preferably cyclopropylene or 1,3-cyclopentenylene, in such a way that the O atoms are not directly linked to one another, and in which one or more H atoms may be replaced by halogen), and X 1 represents F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenyloxy (the latter four groups preferably have 1 to 4 C atoms), more preferably F, Cl, CF3 or OCF3, However, each ring, preferably the phenylene ring, may be optionally substituted with one or two alkyl groups, preferably methyl and / or ethyl groups, preferably one methyl group.

[0104] Preferred are media comprising one or more compounds of groups 1 and 2, groups 1 and 3 or groups 1 and 4, more preferably groups 1 and 2 or groups 1 and 3.

[0105] Also particularly preferred are media comprising one or more compounds of groups 1, 2 and 3 or groups 1, 2 and 4, more preferably groups 1, 2 and 3.

[0106] Preferred are compounds of groups 1, 2, 3 and 4 which have a molecular weight of 425 or more, more preferably 450 or more. The liquid-crystalline media according to the invention preferably contain at most 10% by weight, more preferably at most 5% by weight, of compounds which have a molecular weight of less than 425, more preferably less than 450. The liquid-crystalline media according to the invention preferably consist essentially of compounds which have a molecular weight of 450 or more, more preferably 470 or more.

[0107] For illustrative purposes, the following compounds and their molecular weights are provided: Table: Structures and their molecular weights

[0108] [Table 1]

[0109] The compounds of formula IC can be prepared in a manner known per se under reaction conditions precisely suited to the reactions described and known in the literature (e.g., standard works such as Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), and also using modifications known per se that are not mentioned in more detail in the specification.

[0110] Compounds of formula I in general, and formula IC in particular, can be advantageously prepared as shown in the following illustrative syntheses and examples (Schemes 1 and 2).

[0111] [ka]

[0112] <Scheme 1> Formula IC(Z 1C =-C(O)O-) compounds, where R 1C and X 1C is defined according to the formula IC.

[0113] An alternative reaction route for preparing the corresponding difluoromethyleneoxy (-CF2-O-) compounds is presented herein in Synthetic Scheme 2.

[0114] [ka]

[0115] <Scheme 2>Z 1C is a general synthetic scheme for preparing compounds of formula IC where R = -CF2O- 1C and X 1C is defined according to the formula IC.

[0116] The corresponding starting materials can generally be readily prepared by those skilled in the art by synthetic methods known from the literature or are commercially available.

[0117] The reaction methods and reagents used are in principle known from the literature. Further reaction conditions are exemplified by the examples.

[0118] Further preferred process variations not mentioned above will become apparent from the examples or claims.

[0119] The processing and subsequent working up of the reaction mixture obtained above can be carried out essentially as a batch reaction or in a continuous reaction procedure, which includes, for example, re-reaction in a continuous stirred tank reactor, a cascade of stirred tank reactors, a loop or cross-flow reactor, a flow tube or a microreactor. The reaction mixture can be optionally worked up by removal of solvents and / or azeotropes by filtration through solid phases, chromatography, separation between immiscible phases (e.g., extraction), adsorption on solid supports, distillation, selective distillation, sublimation, crystallization, co-crystallization, nanofiltration on membranes.

[0120] In the present disclosure, the 2,5-disubstituted dioxane ring of the formula: [ka] Preferably, the dioxane ring is in the 2,5-trans configuration, i.e., the substituents R are both equatorial in the preferred chair conformation. 2,5-disubstituted tetrahydropyrans of the formula: [ka] Likewise, it preferably represents a tetrahydropyran ring in the 2,5-trans configuration, ie, the substituents are preferably both equatorial in the preferred chair conformation.

[0121] The present invention also relates to a liquid-crystalline medium comprising one or more compounds of formula I (formulae IA, IB and IC) according to the invention. The liquid-crystalline medium preferably comprises at least two components, each of which preferably has a ferroelectric nematic phase. They are preferably obtained by mixing the components with one another. The process according to the invention for preparing a liquid-crystalline medium is therefore characterized in that at least one compound of formula I (formulae IA, IB and IC) is mixed with at least one further mesogenic, preferably ferroelectric nematic, compound, and additives are optionally added.

[0122] For liquid-crystalline media comprising compounds of the formulae IA and / or IB and / or IC, the achievable combinations of ferroelectric nematic phase temperature range, clearing point, dielectric anisotropy and response time are far superior to previous materials of that type from the prior art, where previously only a limited choice of single-compound materials were available which did not have a full ferroelectric nematic phase range over the relevant temperature range.

[0123] The mixtures according to the invention generally exhibit a very wide nematic phase range with a clearing point above 65° C. as well as a wide ferroelectric nematic phase range.

[0124] The liquid-crystalline media according to the invention preferably exhibit a temperature range of the ferroelectric nematic phase that is at least 20 degrees wide, preferably spanning a range of at least 30 degrees, more preferably at least 40 degrees. Each phase range may be monotropic or enantiotropic, preferably it is enantiotropic.

[0125] Preferably the liquid-crystalline media according to the invention have Preferably, the temperature is 20°C or lower to 30°C or higher. More preferably, 10°C or lower to 40°C or higher. More preferably, it is 0°C or lower to 50°C or higher. Most preferably -20°C or below to 60°C or above The ferroelectric nematic phase is shown.

[0126] In another preferred embodiment the liquid-crystalline medium according to the invention has Preferably, the temperature is 20°C or lower to 30°C or higher. More preferably, 10°C or lower to 35°C or higher. More preferably, it is between 0°C or lower and 40°C or higher. Most preferably -20°C or below to 45°C or above The ferroelectric nematic phase is shown.

[0127] In another preferred embodiment the liquid-crystalline medium according to the invention has Preferably, the temperature is 20°C or lower to 50°C or higher. More preferably, 10°C or lower to 70°C or higher. More preferably, it is 0°C or lower to 90°C or higher. Most preferably -20°C or below to 100°C or above The ferroelectric nematic phase is shown.

[0128] This means that the medium must be at least N f It means to show the phase.

[0129] The liquid-crystalline media according to the invention exhibit outstanding dielectric properties.

[0130] They preferably have an ε 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. ∥ has a value of

[0131] They preferably have an ε 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. ⊥ has a value of

[0132] They preferably have a Δε value of 300 or more, more preferably 400 to 2,100, more preferably 1,400 to 2,300, and most preferably 1,500 to 2,500.

[0133] They preferably have an ε of 20,000 or more at 10 Hz, more preferably 25,000 to 90, more preferably 30,000 to 75,000, and most preferably 38,000 to 60,000. r has a value of

[0134] These dielectric properties are achieved at a temperature where the medium is in the ferroelectric nematic phase. Dielectric properties may exhibit hysteretic behavior, where the value obtained at a certain temperature may depend on the history of the material, i.e., whether it has been heated or cooled.

[0135] This effect allows operation of the device in, for example, a bistable mode, which can be used beneficially in electro-optical devices, as known from, for example, ferroelectric smectic devices, among others.

[0136] The liquid-crystalline media according to the invention preferably contain from 2 to 40, particularly preferably from 4 to 20, compounds as further components 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 components are preferably selected from ferroelectric nematic or nematogenic (monotropic or isotropic) substances.

[0137] Prior art ferroelectric materials and similar compounds with high dielectric anisotropy to be combined with the present material are selected, for example, from the following structures:

[0138] [ka]

[0139] wherein p is 1, 2, 3, 4 or 5.

[0140] The medium according to the invention preferably comprises from 1% to 100%, more preferably from 10% to 100%, particularly preferably from 50% to 100% of compounds of the formulae IA and / or IB and / or IC.

[0141] The liquid crystal mixtures according to the present invention can be prepared by conventional methods. Generally, the desired amount of the component to be used in a smaller amount is dissolved in the component constituting the main component, preferably at elevated temperatures. It is also possible to mix solutions of the components in organic solvents, such as acetone, chloroform or methanol, and then, after thorough mixing, remove the solvent again, for example by distillation. It is also possible to prepare the mixtures by other conventional methods, such as using premixes, for example, homologous mixtures, or using the so-called "multi-bottle" system.

[0142] The dielectric may also contain further additives known to those skilled in the art and described in the literature. For example, pleochroic dyes, chiral dopants, stabilizers, or nanoparticles may be added in amounts of 0-15%, preferably 0-10%. The individual compounds added are used in concentrations of 0.01-6%, preferably 0.1-3%. However, in this specification, the concentration data for the other components of the liquid crystal mixture, i.e., the liquid crystals and mesogenic compounds, are given without taking into account the concentrations of these additives.

[0143] The liquid crystal mixtures according to the invention make it possible to significantly widen the range of available parameters.

[0144] The invention also relates to electro-optical displays containing a medium of this type, in particular TFT displays having two plane-parallel outer plates which together with a frame form a cell, an integrated nonlinear element for switching individual pixels on the outer plates, and a nematic liquid crystal mixture with positive dielectric anisotropy and high resistivity arranged within the cell. The invention further relates to the use of these media for electro-optical purposes.

[0145] The term "alkyl" embraces unbranched and branched alkyl radicals having 1 to 15 carbon atoms, particularly preferably the unbranched radicals methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl and n-heptyl, and also the radicals n-butyl, n-pentyl, n-hexyl and n-heptyl, which are alternatively substituted by one methyl, ethyl or propyl. Radicals having 2 to 5 carbon atoms are generally preferred.

[0146] The term "alkenyl" embraces unbranched and branched alkenyl groups having up to 12 carbon atoms, in particular 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, in particular C2-C7-1E-alkenyl, C4-C7-3E-alkenyl and C5-C7-4-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, etc. Groups having 2 to 5 carbon atoms are generally preferred.

[0147] The expression "halogenated alkyl group" preferably includes mono- or polyfluorinated and / or chlorinated groups. Perhalogenated groups are included. Fluorinated alkyl groups are particularly preferred, in particular CF3, CH2CF3, CH2CHF2, CHF2, CH2F, CHFCF3 and CF2CHFCF3. The expression "halogenated alkenyl group" and related expressions are explained accordingly.

[0148] The total amount of the individual compounds of formula IA and / or IB and / or IC in the mixture according to the invention is not critical, and the mixture may therefore contain one or more further components in order to optimize various properties.

[0149] The structure of the matrix display according to the invention from polarizers, electrode substrates and surface-treated electrodes corresponds to the conventional design for this type of display, the term conventional design being used broadly in this document and including all derivatives and modifications of matrix displays, in particular matrix display elements based on poly-Si TFTs.

[0150] However, the essential difference between a display according to the invention and a display based on a conventional twisted nematic cell lies in the choice of liquid crystal parameters of the liquid crystal layer.

[0151] The following examples are intended to illustrate the present invention without intending to limit it, and those skilled in the art will be able to obtain details from the examples that are not specifically given in the general description, and will be able to generalize them according to their general expertise and apply them to specific problems.

[0152] Above and below, percentage data are expressed as % by weight. Unless otherwise specified, for example, melting point T(C,N), smectic (Sm) to nematic (N) phase transition T(S,N) and clearing point T(N,I), respectively, T(N f All temperature values ​​given in this application, such as (°C), (°F), ...

[0153] The physical, physicochemical and electro-optical parameters are determined in a generally known manner, as described, inter alia, in the document "Merck Liquid Crystals - Licristal® - Physical Properties of Liquid Crystals - Description of Measurement Methods", 1998, Merck KGaA, Darmstadt.

[0154] The appearance of the ferroelectric nematic phase in the material is identified using differential scanning calorimetry (DSC) and by observing the texture under a polarizing microscope equipped with a hot stage for controlled cooling or heating, respectively, and is confirmed by the temperature dependence of the dielectric properties.

[0155] The dielectric anisotropy Δε of the individual substances is determined at 20 °C and 1 kHz. For this purpose, 5-10% by weight of the substance to be examined and measured is dissolved in the dielectrically positive mixture ZLI-4792 (Merck) and the measured value is extrapolated to a concentration of 100%. The optical anisotropy Δn is determined at 20 °C and a wavelength of 589.3 nm.

[0156] The dielectric constant (ε) of the material, especially in the ferroelectric nematic phase, is determined directly by measuring the capacitance of at least one test cell containing the compound, with a cell thickness of 25 μm, and with homeotropic and homogeneous orientation, respectively. The temperature is controlled by a Novocontrol Novocoool system set, with a temperature gradient of + / -1 K / min; + / -2 K / min; + / -5 K / min; + / -10 K / min applied to the sample cell. The capacitance is measured with a Novocontrol α-N analyzer at a frequency of 10 Hz or 1 kHz, with a standard voltage of less than 50 mV down to 0.1 mV, below the threshold of the measured compound. Measurements are performed both during heating and cooling of the sample(s). For simplicity, the term "capacitance" is used herein.

[0157]

number

[0158] In this application, unless expressly stated otherwise, the plural of a term refers to both the singular and the plural, and vice versa. Further combinations of the embodiments and variations of the invention according to the detailed description arise from the appended claims or from multiple combinations of these claims. [Example]

[0159] The invention will now be described in more detail in the following non-limiting examples.

[0160] Compound example <Compound Example 1>: Synthesis of UUQU-4-N

[0161] [ka]

[0162] Process 1.1

[0163] [ka]

[0164] 20.3 ml (203 mmol) of 1,3-propanedithiol was dissolved in 25.9 ml of toluene and warmed to 80 °C. A solution of 34.5 g (135.1 mmol) of 3, 0.2 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. 17.7 ml (200 mmol) of trifluoromethanesulfonic acid was added dropwise over 80 minutes, maintaining the temperature below 25 °C. The toluene was distilled off at 80 °C and 40 mbar, 25 ml of additional toluene was added, and all volatiles were distilled off again. The crystalline residue was used in the next step without further purification.

[0165] Process 1.2

[0166] [ka]

[0167] 93.1 g (0.6 mol) of 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 min, 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 1 h, 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 h and warmed to 0 °C. After the usual workup, 132 g (62%) of 6 was obtained as slightly beige crystals.

[0168] Process 1.3

[0169] [ka]

[0170] 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(pinacolato)boron were added. The mixture was heated under reflux overnight. After the usual workup, 12.4 g (80%) of 7 was obtained as slightly yellow crystals.

[0171] Process 1.4

[0172] [ka]

[0173] 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 the usual workup, 3.42 g (62%) of 9 (UUQU-4-N) was obtained as colorless, transparent crystals.

[0174] 1 H NMR (400MHz, chloroform-d) δ7.16 (d, J=11.0Hz, 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=7.4Hz, 2H), 0.96(t, J=7.3Hz, 3H)

[0175] Molecular weight: 485.4 Melting point: 44℃, clearing point: 21℃ Extrapolated data from a 10% solution in ZLI-4792: Δn(20°C) = 0.120 and Δε(20°C) = 54.6

[0176] Characterization of ferroelectric nematic behavior: Materials, compounds, and mixtures are observed under a polarizing microscope equipped with a temperature-controlled hot stage. Their textures are observed and videotaped. The unique liquid crystal textures characteristic of the ferroelectric nematic phase(s) are identified.

[0177] The dielectric properties are also determined.

[0178] Table: Measurement of ε at different temperatures (cooling rate 1° / min, non-oriented sample on metal surface, ε av. leads to.)

[0179] [Table 2]

[0180] <Compound Example 2>: Synthesis of UUZU-4-N

[0181] [ka]

[0182] Process 2.1

[0183] [ka]

[0184] Process 2.2 57.2 g (150 mmol) of disodium tetraborate decahydrate, 2.8 g (4 mmol) of palladium chloride, 0.2 g (4 mmol) of hydrazinium hydroxide, 39.4 g (0.2 mol) of 1-bromo-3,5-difluorobenzene, 42.8 g (0.2 mol) of 10, and 200 ml of water were combined. The mixture was heated under reflux for 6 hours. After the usual workup, 50 g (88%) of 11 was obtained.

[0185] [ka]

[0186] Process 2.3 50 g (175 mmol) of 11 was dissolved in 300 ml of tetrahydrofuran and cooled to -75 °C. 118 ml (193 mmol) of 15% n-butyl ether in hexane was added dropwise at -70 °C, and the mixture was stirred at that temperature for 1.5 h. The mixture was poured onto 500 g of solid carbon dioxide and allowed to warm to room temperature. After the usual workup, 46.8 g (82%) of 12 was obtained as colorless crystals.

[0187] [ka]

[0188] Process 2.4 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 combined with 200 ml of dichloromethane and cooled to 0 °C. Between 0 °C and 5 °C, a solution of 11.3 g (55 mmol) of N,N-dicyclohexylcarbodiimide in 50 ml of dichloromethane was added dropwise. The mixture was then warmed to room temperature and stirred overnight. 1.4 g of oxalic acid was added, and the whole was stirred for an additional 1.5 hours. After the usual workup, 20.5 g (88%) of 13 (UUZU-4-N) was obtained.

[0189] 1 H NMR (500MHz, chloroform-d) δ7.23~7.17(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=7.4Hz, 2H), 0.96(t, J=7.4Hz, 3H).

[0190] Phase: C69N f / N93I. Extrapolated data from a 10% solution in ZLI-4792: Δn(20° C.)=0.159 and Δε(20° C.)=70.3.

[0191] <Compound Example 3>: Synthesis of UUZU-5-N

[0192] [ka]

[0193] The compound is prepared analogously to Example 2.

[0194] Melting point: 80℃ Extrapolated data from a 10% solution in ZLI-4792: Δn(20°C) = 0.162 and Δε(20°C) = 80.5

[0195] Analogously to Examples 1 and 2, the following compounds are prepared: The following abbreviations are used for the end groups in the table(s) below:

[0196] [Table 3]

[0197] General structure:

[0198] [ka]

[0199] Table: Further compound examples

[0200] [Table 4]

[0201] [Table 5]

[0202] Further combinations of the embodiments of the invention and modifications of the invention are also disclosed by the claims.

[0203] Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting in any way to the remainder of the disclosure. The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and / or operating conditions of the invention for those used in the preceding examples.

[0204] From the foregoing description, those skilled in the art can easily ascertain the essential features of the present invention, and can make various modifications and changes to adapt the present invention to various uses and conditions without departing from the spirit and scope thereof.

[0205] This applies both to the medium as a composition having components which may be groups of compounds and individual compounds of the composition, and also to groups of compounds having their respective components and compounds. As far as the concentration of individual compounds relative to the medium as a whole is concerned, the term "comprising" means that the concentration of the compound(s) or compounds in question is preferably 1% or more, particularly preferably 2% or more, very particularly preferably 4% or more.

[0206] In the present invention, "≦" means less than or equal to, preferably less than, and "≧" means greater than or equal to, preferably greater than.

[0207] In the present invention, [ka] represents trans-1,4-cyclohexylene, [ka] represents a mixture of both cis- and trans-1,4-cyclohexylene, [ka] represents 1,4-phenylene.

[0208] In 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 a compound is determined herein by dissolving 10% of the compound in a liquid crystal host and determining the capacitance of the resulting mixture at 1 kHz in at least one test cell with a cell thickness of 20 μm and in each case with homeotropic and homogeneous surface alignment. The measurement voltage is typically between 0.5 V and 1.0 V, but is always lower than the capacitance threshold of the respective liquid crystal mixture (material) under consideration.

[0209] The host mixture used for the dielectrically positive and dielectrically neutral compounds is ZLI-4792, and the host mixture used for the dielectrically negative compounds is ZLI-2857, both manufactured by Merck, Germany. The value for each compound studied is obtained from the change in the dielectric constant of the host mixture after adding the compound studied and is extrapolated to 100% for the compound used. The compound studied is dissolved in the host mixture in an amount of 10%. If the solubility of the substance is too low for this purpose, the concentration is reduced stepwise by half until the study can be carried out at the desired temperature.

[0210] The liquid-crystalline medium according to the present invention may also contain further additives, such as stabilizers, in the usual amounts, if necessary. The total amount of these additives used is preferably from 0% to 10%, particularly preferably from 0.1% to 6%, based on the total amount of the mixture. The concentration of each compound used is preferably from 0.1% to 3%. The concentrations of these and similar additives are generally not taken into account when specifying the concentration and concentration range of the liquid-crystalline compound in the liquid-crystalline medium.

[0211] For the purposes of the present invention, all concentrations are given in percent by weight unless expressly stated otherwise and relate to the corresponding mixture as a whole or to the entire mixture components unless expressly stated otherwise. In this context, the term "mixture" describes a liquid-crystalline medium.

[0212] Unless otherwise stated, the following symbols are used: T(N,I) respectively T(N f ,I) (or clp.) Clearing point (℃).

[0213] Dielectric properties at 1 kHz and preferably at 20°C or each specified temperature: ε ⊥ Permittivity perpendicular to the director, ε ∥ Dielectric constant parallel to the director, Δε for dielectric anisotropy and selective data for single compounds in particular, and εav. Average dielectric constant.

[0214] and specifically for data from screening of the respective compounds in the nematic host mixture ZLI-4792: n e extraordinary refractive index measured at 20°C and 589 nm, n0Normal refractive index measured at 20°C and 589 nm, and Δn Optical anisotropy measured at 20°C and 589 nm.

[0215] The following examples are intended to illustrate the present invention without limiting it. However, the following examples will provide those skilled in the art with the preferred compounds to be used, their respective concentrations and their combinations with each other, as well as preferred mixing concepts. In addition, the following examples illustrate the feasible properties and property combinations.

[0216] <Table A: Ring elements>

[0217] [Table 6]

[0218] [Table 7]

[0219] [Table 8]

[0220] <Table B: Crosslinking Units>

[0221] [Table 9]

[0222] <Table C: Terminal group>

[0223] [Table 10]

[0224] where n and m each represent an integer (1, 2, 3, 4, 5, 6, 7, etc.) and the three dots "..." are spaces for other abbreviations from this table.

[0225] In addition to the compounds of formula IA, IB and / or IC the mixtures according to the invention preferably comprise one or more of the compounds mentioned below.

[0226] The following abbreviations are used: (n, m, k and l are each independently an integer, preferably 1 to 9, more preferably 1 to 7; k and l can be 0, 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, more 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".)

[0227] In the present invention and the following examples, the structures of liquid crystal compounds are represented by acronyms, and conversion to chemical formulas is performed according to Tables A to C above. 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 2lare linear alkyl or alkenyl groups having n, m and l C atoms, respectively. Preferably, n, m and l are each, independently of one another, 1, 2, 3, 4, 5, 6 or 7. Table A shows the codes for the ring elements of the core structure of the compounds, Table B lists the bridging groups, and Table C lists the meaning of the codes for the left and right terminal groups of the molecule. The initial letter consists of the code for the ring element with any linking groups, followed by a first hyphen and the code for the left terminal group, and a second hyphen and the code for the right terminal group. Table D shows exemplary structures of the compounds with their respective abbreviations.

[0228] Examples of preferred compounds of formula IA

[0229] [Table 11]

[0230] Examples of preferred compounds of formula IB

[0231] [Table 12]

[0232] Examples of Preferred Compounds of Formula IC

[0233] [Table 13] TIFF0007799692000089.tif193166

[0234] Further compounds which are preferably used

[0235] [Table 14]

[0236] [Table 15]

[0237] [Table 16]

[0238] [Table 17]

[0239] [Table 18]

[0240] [Table 19]

[0241] [Table 20]

[0242] In the formula, n, m, and l are 1, 2, 3, 4, 5, 6, 7, etc., and n may also be 0.

[0243] <Mixture example> Exemplary mixtures are disclosed below.

[0244] <Mixture example 1> The following mixture (M-1) is prepared and studied:

[0245] [Table 21]

[0246] On cooling, this mixture M-1 exhibits a ferroelectric nematic phase from 40°C to 5°C. This phase is monotropic, i.e., it can be supercooled. On heating, the phase reappears at about 35°C and again changes to a different mesophase at about 45°C. The phase is confirmed by microscopy and DSC. The mixture exhibits a very high dielectric constant at these temperatures.

[0247] At higher temperatures, hysteresis in the dielectric constant is observed. At temperatures of about 60°C, the conventional nematic phase occurs.

[0248] <Mixture example 2> The following mixture (M-2) is prepared and studied:

[0249] [Table 22]

[0250] This mixture M-2 exhibits a ferroelectric nematic phase, which remains in the ferroelectric nematic state over the range of 30°C to 25°C upon cooling.

[0251] <Mixture example 3> The following mixture (M-3) is prepared and studied:

[0252] [Table 23]

[0253] This mixture M-3 exhibits a ferroelectric nematic phase, which changes from 46°C to 25°C upon cooling.

[0254] <Mixture example 4> The following mixture (M-4) is prepared and studied:

[0255] [Table 24]

[0256] This mixture M-4 exhibits a ferroelectric nematic phase, which varies from 77°C to 31°C upon cooling.

[0257] <Mixture example 5> The following mixture (M-5) is prepared and studied:

[0258] [Table 25]

[0259] This mixture M-5 exhibits a ferroelectric nematic phase below 62° C. It is metastable at 20° C. upon cooling.

[0260] <Mixture example 6> The following mixture (M-6) is prepared and studied:

[0261] [Table 26]

[0262] This mixture M-6 exhibits a ferroelectric nematic phase below 49°C.

[0263] <Mixture example 7> The following mixture (M-7) is prepared and studied:

[0264] [Table 27]

[0265] This mixture M-7 exhibits a ferroelectric nematic phase, which is metastable at 20°C upon cooling.

[0266] <Mixture example 8> The following mixture (M-8) is prepared and studied:

[0267] [Table 28]

[0268] This mixture M-8 exhibits a stable ferroelectric nematic phase below 48°C.

[0269] <Mixture example 9> The following mixture (M-9) is prepared and studied:

[0270] [Table 29]

[0271] This mixture M-9 exhibits a ferroelectric nematic phase at ambient temperature.

[0272] <Mixture example 10> The following mixture (M-10) is prepared and studied:

[0273] [Table 30]

[0274] This mixture M-10 exhibits a ferroelectric nematic phase below 59°C.

[0275] <Mixture example 11> The following mixture (M-11) is prepared and studied:

[0276] [Table 31]

[0277] This mixture M-11 exhibits a ferroelectric nematic phase over at least the temperature range of 19°C to 36°C.

[0278] <Mixture example 12> The following mixture (M-11) is prepared and studied:

[0279] [Table 32]

[0280] This mixture M-12 exhibits a ferroelectric nematic phase, which occurs at least over the range of 60°C to 73°C when heated and 73°C to 10°C when cooled.

Claims

1. A liquid-crystalline medium comprising two or more compounds of formula IA in a total concentration of at least 40% by weight, the liquid-crystalline medium exhibiting a ferroelectric nematic phase at ambient temperature. 【Chemistry 1】 (In the formula, X 1A represents —F, —CF 3 , —OCF 3 , —Cl, —NCS or —CN; Z 1A represents —(C═O)—O— or —CF 2 —O—; L 1A represents H or CH 3 ; 【Chemistry 2】 represents R 1A is an alkyl group having 1 to 15 C atoms (provided that in addition, one or more CH 2 groups in these groups may in each case independently be -C≡C-, -CF 2 -O-, -OCF 2 -, -CH═CH-, ...C≡C-, -C≡C-, -C� 【Transformation 3】 -O-, -S-, -CO-O- or -O-CO-, provided that in addition one or more H atoms may be replaced by halogen.

2. The medium of claim 1, consisting essentially of a compound of formula IA.

3. comprising one, two or more compounds selected from the group of compounds of formula IA, IB and IC, Liquid-crystalline medium, with the proviso that the total concentration of compounds of the formulae IA, IB and IC is at least 90% by weight. 【Chemistry 4】 (In the formula, X １Ａ , X １Ｂ and X １Ｃ each independently represents —F or —CN, Z １Ａ , Z １Ｂ and Z １Ｃ are each independently —(C═O)—O— or —CF ２ represents —O—, L １Ａ , L １Ｂ and L １Ｃ each independently represents H or CH3, 【Transformation 5】 represents 【Transformation 6】 represents 【Transformation 7】 represents R １Ａ , R １Ｂ and R １Ｃ are each independently an alkyl group having 1 to 15 carbon atoms (provided that in addition, one or more CH ２ The groups may be in each case independently of one another, such that the O / S atoms are not directly linked to one another, such as -C≡C-, -CF ２ -O-, -OCF ２ -, -CH=CH-, 【Transformation 8】 -O-, -S-, -CO-O- or -O-CO-, provided that in addition one or more H atoms may be replaced by halogen.

4. The medium of claim 3, consisting essentially of compounds of formulae IA, IB and IC.

5. The medium of claim 3 or 4, wherein the total concentration of the compound of formula IA is 40% by weight or more.

6. A medium according to claim 3 or 4, consisting essentially of a compound of formula IA.

7. A medium according to any one of claims 1 to 6, characterized in that the compound of formula IA contains one or more compounds selected from the compounds of formula IA-1 to IA-3. 【Chemistry 9】

8. The medium according to any one of claims 3 to 7, which exhibits a ferroelectric nematic phase.

9. A medium according to any one of claims 3 to 8, comprising one, two or more compounds of formula IA as defined in claim 3.

10. A medium according to any one of claims 3 to 9, comprising one, two or more compounds of formula IB as defined in claim 3.

11. A medium according to any one of claims 3 to 10, comprising one, two or more compounds of formula IC as defined in claim 3.

12. A medium according to any one of claims 3 to 11, comprising one, two or more compounds selected from two or all three of formulae IA, IB and IC, respectively.

13. A medium according to any one of claims 3 to 12, which exhibits a ferroelectric nematic phase over at least the temperature range of 0°C to 40°C.

14. A medium according to any one of claims 3 to 12, which exhibits a ferroelectric nematic phase at least at ambient temperature.

15. 15. The medium according to claim 1, which exhibits a dielectric anisotropy of 400 or more at 20° C. and 1 kHz.

16. A medium according to any one of claims 1 to 15, which exhibits hysteresis in its dielectric properties.

17. Use of a liquid crystal medium according to any one of claims 1 to 16 for providing a ferroelectric nematic liquid crystal material.

18. Use of a liquid-crystalline medium according to any one of claims 1 to 16 for energy-saving display or electrical applications.

19. Electro-optical liquid crystal display comprising a liquid crystal medium according to any one of claims 1 to 16.

20. 17. Process for preparing a liquid-crystalline medium according to any one of claims 3 to 16, comprising mixing one or more compounds selected from the group of compounds of the formulae IA, IB and IC as given in claim 3, respectively with one another or with one or more other compounds.

21. A method for operating an electro-optical device using a liquid crystal material according to any one of claims 1 to 16, which exhibits hysteresis in its dielectric properties.

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