Compound, liquid crystal medium, and liquid crystal display including the same

Abstract

The present invention relates to a liquid crystal medium having a nematic phase, which comprises one or more compounds of formula X, wherein the parameters have the meanings given herein, to its use in electro-optical displays, in particular in active matrix displays based on the IPS or FFS effect, to displays of this type containing a liquid crystal medium of this type, and to the use of compounds of formula X for improving the transmittance and / or response time of a liquid crystal medium comprising one or more further mesogenic compounds, and to certain compounds of formula X which are specific in the text.

Description

[0001] The present invention relates to novel liquid crystal dielectrics, in particular for liquid crystal displays, and to these liquid crystal displays, in particular to liquid crystal displays using the IPS (in-plane switching) or preferably the FFS (fringe field switching) effect (both using dielectrically positive liquid crystals). The latter is also occasionally referred to as the SG-FFS (super-overdrive FFS) effect. For this effect, dielectrically positive liquid crystals are used which contain one or more compounds having a high dielectric constant both parallel and perpendicular to the molecular director, which results in a large average dielectric constant and a high dielectric ratio. The liquid crystal dielectric optionally additionally contains dielectrically negative, dielectrically neutral compounds or both. The liquid crystal dielectric is used for planar (i.e., in-plane) initial alignment. The liquid crystal dielectric of the present invention has positive dielectric anisotropy and contains compounds having a large dielectric constant both parallel and perpendicular to the molecular director.

[0002] The medium is characterized by a particularly high transmittance and a reduced response time in the respective displays, which is brought about by their unique combination of physical properties, in particular by their dielectric properties and especially by their high (ε ⊥ / ε av. ) ratio or their high dielectric ratio (ε ⊥ / Δε). This also results in their excellent performance in the displays according to the present invention.

[0003] IPS and FFS displays using dielectrically positive liquid crystals are well known in the art and have been widely adopted in various types of displays, such as desktop monitors and televisions, and also for mobile applications.

[0004] However, currently, IPS and especially FFS displays using dielectrically negative liquid crystals are widely adopted. The latter is sometimes also referred to as UB-FFS (ultra-bright FFS). Such displays are disclosed, for example, in US 2013 / 0207038 A1. Compared to the previously used IPS- and FFS displays (which already use dielectrically positive liquid crystals), these displays are characterized by a significantly increased transmittance. However, these displays using conventional dielectrically negative liquid crystals have serious drawbacks: they require a higher operating voltage compared to the respective displays using dielectrically positive liquid crystals. The liquid crystal dielectric for UB-FFS has a dielectric anisotropy of -0.5 or less and preferably -1.5 or less.

[0005] The liquid crystal dielectric for HB-FFS (high-brightness FFS) has a dielectric anisotropy of 0.5 or greater and preferably 1.5 or greater. Liquid crystal dielectrics for HB-FFS containing both dielectrically negative and dielectrically positive liquid crystal compounds, or mesogenic compounds, are disclosed, for example, in US2013 / 0207038 A1. These media are characterized by already having a relatively large ε ⊥ and εav. values, but their ratio (ε ⊥ / Δε) is relatively small.

[0006] However, according to the present application, it is preferred to have an IPS or FFS effect with a dielectric positive liquid crystal medium having planar alignment.

[0007] The industrial application of this effect in electro-optical display elements requires a liquid crystal phase that must meet various requirements. Of particular importance here are the chemical resistance to moisture and air and the physical effects such as heat, radiation in the infrared, visible, and ultraviolet regions, and direct current (DC) and alternating current (AC) electric fields.

[0008] In addition, industrially available liquid crystal phases need to have a liquid crystal mesophase within a suitable temperature range and at low viscosity.

[0009] None of the series of compounds having a liquid crystal mesophase disclosed so far includes a single compound that meets all these requirements. Therefore, mixtures of 2 - 25 compounds, preferably 3 - 18 compounds, are usually prepared to obtain a substance that can be used as a liquid crystal phase.

[0010] Matrix liquid crystal displays (MLC displays) are known. Nonlinear elements that can be used for individual switching of each pixel are, for example, active elements (i.e., transistors). Thus, the term "active matrix" is used, where thin film transistors (TFTs) are usually used, which are usually arranged on a glass plate serving as a substrate.

[0011] The difference between the two technologies lies in: TFTs containing compound semiconductors such as CdSe, or metal oxides such as ZnO, or TFTs based on polycrystalline and especially amorphous silicon. Currently, the latter technology has the greatest commercial importance globally.

[0012] The TFT matrix is applied to the inner side of one glass plate of the display, while the other glass plate has a transparent counter electrode on its inner side. Compared with the size of the pixel electrodes, the TFTs are very small and have almost no adverse effect on the image. This technology can also be extended to displays with full-color functionality, where mosaics of red, green, and blue filters are arranged in such a way that the filter elements are arranged opposite each switchable pixel.

[0013] The most commonly used TFT displays so far usually operate with a crossed polarizer in transmission and are backlit. For TV applications, ECB (or VAN) cells or FFS cells are used, while monitors usually use IPS cells or TN (twisted nematic) cells, and notebooks, laptops, and mobile applications usually use TN, VA, or FFS cells.

[0014] Here the term MLC display includes any matrix display with integrated non-linear elements, i.e., in addition to active matrices, also displays with passive elements such as varistors or diodes (MIM = metal-insulator-metal).

[0015] This type of MLC display is particularly suitable for TV applications, monitors and notebooks or for displays with a high information density, for example in automotive manufacturing or aircraft construction. In addition to problems regarding the angular dependence of the contrast and the response time, there are also some problems in MLC displays due to the not high enough specific resistance of the liquid crystal mixture [TOGASHI, S., SEKI-GUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay 84, Sept. 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, pp. 141ff., Paris; STROMER, M., Proc. Eurodisplay 84, Sept. 1984: Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays, page 145, Paris]. With decreasing resistance, the contrast of the MLC display deteriorates. Since the specific resistance of the liquid crystal mixture usually decreases with the lifetime of the MLC display due to the interaction with the inner surface of the display, a high (initial) resistance is very important for the display in order to have an acceptable resistance value during long operation.

[0016] In addition to IPS displays (e.g.: Yeo, S.D., Paper 15.3: “An LC Display for the TV Application“, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pages 758 and 759) and the long-known TN displays, displays using the ECB effect have established the so-called VAN (vertically aligned nematic) displays as one of the three most important newer types of liquid crystal displays today, especially for TV applications.

[0017] The most important designs that can be mentioned here are: MVA (Multi-Domain Vertical Alignment, e.g., Yoshide, H., et al., Paper 3.1: “MVA LCD for Notebook or Mobile PCs...”, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pp. 6 to 9, and Liu, C.T., et al., Paper 15.1: “A 46-inch TFT-LCD HDTV Technology...”, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 750 to 753), PVA (Patterned Vertical Alignment, e.g., Kim, SangSoo, Paper 15.4: “Super PVA Sets New State-of-the-Art for LCD-TV”, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 760 to 763) and ASV (Advanced Super View, e.g., Shigeta, Mitzuhiro and Fukuoka, Hirofumi, Paper 15.2: “Development of High Quality LCD TV”, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 754 to 757). More modern versions of the VA effect are the so-called PAVA (Photo-Aligned VA) and PSVA (Polymer-Stabilized VA).

[0018] The technology has been compared in general form, for example, in Souk, Jun, SID Seminar 2004, Seminar M-6: “Recent Advances in LCD Technology”, Seminar Lecture Notes, M-6 / 1 to M-6 / 26, and Miller, Ian, SID Seminar 2004, Seminar M-7: “LCD-Television”, Seminar Lecture Notes, M-7 / 1 to M-7 / 32. Although the response time of modern ECB displays has been significantly improved by overdrive through addressing methods, such as Kim, Hyeon Kyeong et al., Paper 9.1: “A 57-in. Wide UXGA TFT-LCD for HDTV Application”, SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book I, pages 106 to 109, achieving video-compatible response times, especially in the switching of gray levels, remains an unsolved problem.

[0019] ECB displays, such as ASV displays, use a liquid crystal medium with negative dielectric anisotropy (Δε), while TN and all conventional IPS displays to date use a liquid crystal medium with positive dielectric anisotropy. However, there is an increasing demand for IPS and FFS displays that utilize a dielectric negative liquid crystal medium.

[0020] In this type of liquid crystal display, the liquid crystal is used as a dielectric, and its optical properties change reversibly when a voltage is applied.

[0021] Since generally in a display, that is, also in a display based on these mentioned effects, the operating voltage should be as low as possible, a liquid crystal medium mainly composed of liquid crystal compounds is used. All these liquid crystal compounds have the same sign of dielectric anisotropy and the highest possible value of dielectric anisotropy. Generally, a relatively small proportion of neutral compounds is used at most, and if possible, compounds with a dielectric anisotropy of the opposite sign to that of the medium are not used. In the case of a liquid crystal medium with negative dielectric anisotropy, such as for an ECB or UB-FFS display, compounds with negative dielectric anisotropy are mainly used. The liquid crystal media used usually mainly consist of and usually even essentially consist of liquid crystal compounds with negative dielectric anisotropy.

[0022] In the media used according to the present application, a significant amount of dielectrically positive liquid crystal compounds is typically employed, and usually only a very small amount of dielectric compounds or even no dielectric compounds at all, since liquid crystal displays typically aim to have the lowest possible addressing voltage. At the same time, in certain cases, it can be advantageous to use a small amount of dielectrically neutral compounds.

[0023] US2013 / 0207038 A1 discloses a liquid crystal medium for an HB-FFS display, proposing to improve the performance of an FFS display using liquid crystals with positive dielectric anisotropy by additionally incorporating dielectrically negative liquid crystals. However, this results in the need to compensate for the negative contribution of these compounds to the overall dielectric anisotropy of the resulting medium. For this purpose, the concentration of dielectrically positive materials must be increased, which in turn leaves less room for using dielectrically neutral compounds as diluents in the mixture, or, alternatively, compounds with stronger positive dielectric anisotropy must be used. Both of these alternatives have the serious drawback of increasing the response time of the liquid crystals in the display.

[0024] Liquid crystal media with positive dielectric anisotropy for IPS and FFS displays have been disclosed. Some examples will be given below.

[0025] CN104232105A, WO2014 / 192390, and WO 2015 / 007131 disclose liquid crystal media with positive dielectric anisotropy, some of which have a rather high dielectric constant perpendicular to the director.

[0026] Obviously, the phase range of the liquid crystal mixture must be wide enough for the desired display applications.

[0027] The response time of the liquid crystal medium in the display must also be improved, i.e., reduced. This is particularly important for displays for television or multimedia applications. To improve the response time, it has been repeatedly proposed in the past to optimize the rotational viscosity (γ 1 ) of the liquid crystal medium, i.e., to obtain a medium with the lowest possible rotational viscosity. However, the results achieved here are insufficient for many applications, and thus it is desirable to find further optimized methods.

[0028] Among them, US 2016-0298033(A) particularly discloses the following compounds for LCDs:

[0029]

[0030] While US 2016-0298034(A) particularly discloses compounds of the following formula:

[0031]

[0032]

[0033] and various compounds for the same use have been proposed.

[0034] European Patent Application EP 18 203 594.9 discloses compounds of the following general formula

[0035]

[0036] and the following specific compounds

[0037]

[0038]

[0039] and their use in a liquid host mixture having a simple mixture composition.

[0040] The sufficient stability of the medium with respect to the ultimate load, especially with respect to UV exposure and heating, is of particular importance. This can be crucial especially in the case of applications in mobile device (e.g., mobile phone) displays.

[0041] In addition to their relatively poor transmittance and their relatively long response times, the MLC displays disclosed so far also have other disadvantages. These are, for example, their relatively low contrast, their relatively high viewing angle dependence and the difficulty in reproducing gray levels in these displays, especially when viewed from an oblique viewing angle, as well as their insufficient VHR and their insufficient lifetime. Desired improvements in the transmittance of the displays and their response times are needed to improve their energy efficiency or their ability to render rapidly moving pictures, respectively.

[0042] Therefore, there is still a great demand for MLC displays having a very high specific resistance while having a large operating temperature range, short response times and a relatively low threshold voltage, with the help of which a plurality of gray levels can be produced and which particularly have good and stable VHR.

[0043] The object of the present invention is to provide MLC displays for use not only in monitor and TV applications but also in mobile applications such as telephones and navigation systems, which are based on the ECB, IPS or FFS effect and do not have the above-mentioned defects or have the above-mentioned disadvantages only to a reduced extent, and at the same time have a very high specific resistance value. In particular, for mobile phones and navigation systems, it must be ensured that they also operate at extremely high and extremely low temperatures.

[0044] Surprisingly, it has been found that such liquid crystal displays, in particular IPS and FFS displays, can be obtained if a nematic liquid crystal mixture as described below is used in these display elements, which have a low threshold voltage and a short response time, a sufficiently wide nematic phase, a favorable birefringence (Δn) and at the same time a high transmittance, good stability against decomposition by heating and UV exposure, and a stable high VHR, wherein the nematic liquid crystal mixture comprises at least one, preferably two or more compounds of formula X, preferably selected from compounds of sub-formulas XA and XB, particularly preferably compounds of sub-formulas XA and / or XB, more preferably both of formula XA and formula XB, and preferably additionally one or more compounds selected from compounds of formula I and B, preferably selected from compounds of sub-formulas B-1 and B-2 and I-1 and I-2 respectively, particularly preferably selected from compounds of sub-formulas I-1 and / or I-2 and B-1 and / or B-2, most preferably compounds of formula I-2, B-1 and B-2 and most preferably both of formula I-1 and formula I-2 and compounds of formula B-1 and / or B-2, and preferably additionally at least one, preferably two or more compounds selected from compounds of formula II and III, the former preferably of formula II-1 and / or II-2, and / or at least one, preferably two or more compounds selected from compounds of formula IV and / or V, and preferably one or more compounds selected from compounds of formula VII to IX (all formulas are defined herein below).

[0045] This type of medium can be used in particular for electro-optical displays with active matrix addressing, such as IPS- or FFS-displays.

[0046] Accordingly, the present invention relates to a liquid crystal medium comprising polar compounds, which comprises one or more compounds having a dielectric anisotropy (Δε) of 0.5 or higher and preferably a dielectric ratio (ε ⊥ / Δε) of the dielectric constant perpendicular to the director and the dielectric anisotropy of 2.0 or less, and preferably a high dielectric constant (ε ⊥ ) perpendicular to the director of 3.8 or higher, preferably 4.5 or higher, most preferably 6.0 or higher.

[0047] A ratio (ε ⊥ / Δε) of the dielectric constant perpendicular to the director of 1.0 or greater corresponds to a ratio (ε || ) of the dielectric constant parallel to the director of 2.0 or less and the dielectric constant perpendicular to the director (ε ⊥ ) (ε || / ε ⊥ ).

[0048] The medium according to the invention preferably further comprises one or more compounds selected from compounds of formulae II and III, preferably one or more compounds of formula II, more preferably one or more compounds of formula III in addition, and most preferably one or more compounds selected from compounds of formulae IV and V and again preferably one or more compounds selected from compounds of formulae VI - IX (all formulae are defined as follows).

[0049] The mixtures according to the invention exhibit a very wide nematic range (clear point ≥ 70 °C), very favorable capacitance thresholds, relatively high holding ratio values and at the same time good low temperature stability at -20 °C and -30 °C, as well as a very low rotational viscosity. The mixtures according to the invention are further characterized by a good ratio of the clear point to the rotational viscosity and a relatively high positive dielectric anisotropy.

[0050] Now, it has surprisingly been found that FFS type LCDs using liquid crystals with positive dielectric anisotropy can be achieved by using specifically selected liquid crystal media. These media are characterized by a specific combination of physical properties. The most decisive of these are their dielectric properties and here a high average dielectric constant (ε av. ), a high dielectric constant perpendicular to the director of the liquid crystal molecules (ε ⊥ ), and in particular, a relatively high ratio of these latter two values: (ε ⊥ / Δε).

[0051] On the one hand, the liquid crystal media according to the invention preferably have a dielectric anisotropy value of 1.5 or greater, preferably 3.5 or greater, more preferably 4.5 or greater. On the other hand, they preferably have a dielectric anisotropy of 26 or less.

[0052] On the one hand, the liquid crystal media according to the invention preferably have a dielectric constant value perpendicular to the director of 2 or greater, more preferably 6 or greater and on the other hand preferably 20 or less.

[0053] Preferably, the dielectric ratio (ε ⊥ / Δε) of the liquid crystal media according to the invention is preferably 2.0 or less, more preferably 1.5 or less, most preferably 1.0 or less.

[0054] In a preferred embodiment, the liquid crystal media according to the invention have positive dielectric anisotropy, preferably from 1.5 or greater to 20.0 or less, more preferably from 3.0 or greater to 8.0 or less and most preferably from 4.0 or greater to 7.0 or less.

[0055] In a preferred embodiment, which may be the same as the above preferred embodiments, the liquid crystal media according to the invention have a dielectric constant (ε ⊥), more preferably 6.0 or greater, more preferably 7.0 or greater, more preferably 8.0 or greater, more preferably 9.0 or greater, and most preferably 10.0 or greater.

[0056] The liquid crystal medium of the present invention has a dielectric anisotropy of 0.5 or greater, preferably 1.5 or greater, and a dielectric ratio (ε⊥ / Δε) of 2.0 or less, and contains

[0057] a) one or more compounds of formula X, preferably in a concentration range of 1% to 60%, more preferably 5% to 40%, particularly preferably 8% to 35%,

[0058]

[0059] wherein

[0060] W represents O or S,

[0061] R 1X and R 2X each independently represents H, an alkyl group having 1 to 15 C atoms, wherein one or more CH 2 groups may each independently be replaced by -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen, and

[0062] R 1X preferably represents, preferably an alkyl or alkoxy group having 1 to 7 C atoms, or an alkenyl group having 2 to 7 C atoms, more preferably an alkyl or alkoxy group having 2 to 5 C atoms, or an alkenyl group having 2 to 5 C atoms,

[0063] R 2X optionally and in a preferred embodiment, represents X X ,

[0064] A is the same or different each time it appears and represents a group selected from the group consisting of:

[0065] a) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene and decahydronaphthalene-2,6-diyl, wherein one or more non-adjacent CH 2 groups may be replaced by -O- and / or -S-, and wherein one or more H atoms may be replaced by F,

[0066] b) the group consisting of 1,4-phenylene and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by L,

[0067] c) the group consisting of 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, thiophene-2,5-diyl, selenophene-2,5-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, each of which may be mono- or polysubstituted by L,

[0068] d) the group consisting of bicyclo-[1.1.1]-pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl and spiro-[3.3]-heptane-2,6-diyl, in which one or more H atoms may be replaced by F,

[0069] L each, identically or differently, represents halogen, cyano, alkyl having 1 to 7 C atoms, alkoxy, alkylcarbonyl or alkoxycarbonyl, in which one or more H atoms may be substituted by F or Cl,

[0070] Z, at each occurrence, represents, the same or different, a single bond, -CF 2 O-、-OCF 2 -、-CH 2 CH 2 -、-CF 2 CF 2 -、-C(O)O-、-OC(O)-、-CH 2 O-、-OCH 2 -, -CF=CH-, -CH=CF-, -CF=CF-, -CH=CH- or -C≡C-,

[0071] n represents 0, 1 or 2, preferably 0 or 1,

[0072] Y 1 , Y 2 and Y 3 Identical or different representations of H, F, Cl, CF 3 or CHF 2 , where Y 1 and Y 2 One of them is not H or Y 3 is F, and if Y 1 and Y 3 All are F, then Y 2 Not H, and preferably Y 1 It's H, Y 2 and Y 3 It's F.

[0073] X Xrepresenting F, Cl, CN, NCS, SF 5 , fluorinated alkyl, alkoxy, alkenyl or alkenyloxy groups each having at most 5 carbon atoms, preferably F, CF 3 , OCF 3 or NCS,

[0074] and one or more additional compounds, preferably selected from the group of compounds according to conditions b) to f):

[0075] b) one or more dielectrically positive compounds selected from the compounds of formula II and III, preferably each having a dielectric anisotropy greater than 3, preferably one or more compounds of formula II:

[0076]

[0077] wherein

[0078] R 2 represents an alkyl, alkoxy, fluoroalkyl or fluoroalkoxy group having 1 - 7 C atoms, an alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl group having 2 - 7 C atoms and preferably being an alkyl or alkenyl group,

[0079]

[0080] each independently represents, upon each occurrence

[0081]

[0082]

[0083] preferably

[0084]

[0085] L 21 and L 22 represent H or F, preferably L 21 represents F,

[0086] X 2 represents a halogen, a haloalkyl or alkoxy group having 1 - 3 C atoms, or a haloalkenyl or alkenyloxy group having 2 or 3 C atoms, preferably F, Cl, -OCF 3 , -O-CH 2 CF 3 , -O-CH=CH 2 , -O-CH=CF 2 or -CF 3 , very preferably F, Cl, -O-CH=CF 2 or -OCF 3 ,

[0087] m represents 0, 1, 2 or 3, preferably 1 or 2, and particularly preferably 2,

[0088] R 3 represents an alkyl, alkoxy, fluoroalkyl or fluoroalkoxy group having 1 - 7 C atoms, an alkenyl, alkenoxy, alkoxyalkyl or fluoroalkenyl group having 2 - 7 C atoms, and preferably an alkyl or alkenyl group,

[0089]

[0090] are, independently of one another in each occurrence,

[0091]

[0092] preferably

[0093]

[0094] L 31 and L 32 independently of one another represent H or F, preferably L 31 represents F,

[0095] X 3 represents a halogen, a haloalkyl or alkoxy group having 1 - 3 C atoms, or a haloalkenyl or alkenoxy group having 2 or 3 C atoms, preferably F, Cl, -OCF 3 , -OCHF 2 , -O - CH 2 CF 3 , -O - CH=CF 2 , -O - CH=CH 2 or -CF 3 , very preferably F, Cl, -O - CH=CF 2 , -OCHF 2 or -OCF 3 ,

[0096] Z 3 represents -CH 2 CH 2 -, -CF 2 CF 2 -, -COO -, trans -CH=CH -, trans -CF=CF -, -CH 2 O - or a single bond, preferably -CH 2 CH 2 -, -COO -, trans -CH=CH - or a single bond, and very preferably -COO -, -CH 2 CH 2 -, or a single bond, and,

[0097] n represents 0, 1, 2 or 3, preferably 1, 2 or 3 and particularly preferably 1, and,

[0098] c) Optionally, preferably compulsorily, one or more dielectrically neutral compounds selected from the formulas IV and V:

[0099]

[0100]

[0101] wherein

[0102] R 41 and R 42 independently of one another have the meanings given above for R in formula II, preferably R 2 represents alkyl and R 41 represents alkyl or alkoxy or R 42 represents alkenyl and R 41 represents alkyl, 42

[0103]

[0104]

[0105]

[0106] appears twice

[0107] these also independently of one another represent,

[0108]

[0109]

[0110] Preferably,

[0111] one or more of

[0112] represent

[0113]

[0114] Z 41 and Z 42 independently of one another and if Z 41 appears twice, then these also independently of one another represent -CH 2 CH 2 -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH 2 O-, -CF 2 O-, -C≡C- or a single bond, preferably one or more of which represent a single bond, and

[0114] p represents 0, 1 or 2, preferably 0 or 1, and

[0115] R 51 and R 52 each independently has for R 41 and R 42 one of the meanings shown and preferably represents an alkyl group having 1 - 7 C atoms, preferably an n-alkyl group, particularly preferably an n-alkyl group having 1 - 5 C atoms, an alkoxy group having 1 - 7 C atoms, preferably an n-alkoxy group, particularly preferably an n-alkoxy group having 2 - 5 C atoms, an alkoxyalkyl, alkenyl or alkenyloxy group having 2 - 7 C atoms, preferably an alkoxyalkyl, alkenyl or alkenyloxy group having 2 - 4 C atoms, preferably an alkenyloxy group,

[0116]

[0117] if present, each independently represents

[0118]

[0119]

[0120] preferably

[0121]

[0122] preferably

[0123] represents

[0124] and if present, then

[0125] preferably represents

[0126] Z 51 to Z 53 each independently represents -CH 2 -CH 2 -, -CH 2 -O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH 2 -CH 2 -, -CH 2 -O- or a single bond and particularly preferably a single bond,

[0127] i and j each independently represent 0 or 1,

[0128] (i + j) preferably represents 0, 1 or 2, more preferably 0 or 1, and most preferably 1,

[0129] d) Again, optionally, preferably compulsorily, or alternatively or additionally, one or more dielectrically negative compounds selected from formulae VI - IX:

[0130]

[0131] wherein

[0132] R 61 represents an unsubstituted alkyl group having 1 - 7 C atoms, preferably a straight-chain alkyl group, more preferably an n-alkyl group, most preferably a propyl or pentyl group, an unsubstituted alkenyl group having 2 - 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably having 2 - 5 C atoms, an unsubstituted alkoxy group having 1 - 6 C atoms or an unsubstituted alkenyloxy group having 2 - 6 C atoms,

[0133] R 62 represents an unsubstituted alkyl group having 1 - 7 C atoms, an unsubstituted alkoxy group having 1 - 6 C atoms or an unsubstituted alkenyloxy group having 2 - 6 C atoms, and

[0134] l represents 0 or 1,

[0135] R 71 represents an unsubstituted alkyl group having 1 - 7 C atoms, preferably a straight-chain alkyl group, more preferably an n-alkyl group, most preferably a propyl or pentyl group, or an unsubstituted alkenyl group having 2 - 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably having 2 - 5 C atoms,

[0136] R 72 represents an unsubstituted alkyl group having 1 - 7 C atoms, preferably having 2 - 5 C atoms, an unsubstituted alkoxy group having 1 - 6 C atoms, preferably having 1, 2, 3 or 4 C atoms, or an unsubstituted alkenyloxy group having 2 - 6 C atoms, preferably having 2, 3 or 4 C atoms, and

[0137] represents

[0138]

[0139] R 81 represents an unsubstituted alkyl group having 1 - 7 C atoms, preferably a straight-chain alkyl group, more preferably an n-alkyl group, most preferably a propyl or pentyl group, or an unsubstituted alkenyl group having 2 - 7 C atoms, preferably a straight-chain alkenyl group, particularly preferably having 2 - 5 C atoms,

[0140] R 82represents an unsubstituted alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms, preferably having 1, 2, 3 or 4 C atoms, or an unsubstituted alkenyloxy group having 2 to 6 C atoms, preferably having 2, 3 or 4 C atoms,

[0141] represents

[0142]

[0143] preferably

[0144]

[0145] more preferably

[0146]

[0147] Z 8 represents -(C=O)-O-,-CH 2 -O-,-CF 2 -O- or -CH 2 -CH 2 -,preferably -(C=O)-O- or -CH 2 -O-,and

[0148] o represents 0 or 1,

[0149] R 91 and R 92 independently of one another have the meanings given above for R 72 as defined,

[0150] R 91 preferably represents an alkyl group having 2 to 5 C atoms, preferably having 3 to 5 C atoms,

[0151] 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,

[0152] represents

[0153] p and q each independently of one another represent 0 or 1, and

[0154] (p + q) preferably represents 0 or 1,

[0155] if

[0156] represents

[0157] Optionally, preferably p = q = 1.

[0158] e) Optionally, preferably compulsorily, one or more compounds of formula B, preferably selected from compounds of formulae B-1 and B-2, preferably in a concentration range of 1% to 60%, more preferably 5% to 40%, and particularly preferably 8% to 35%,

[0159]

[0160] wherein

[0161] denotes

[0162]

[0163] independently of one another each time they occur,

[0164]

[0165] preferably

[0166] n represents 1 or 2, preferably 1,

[0167] R 1 represents alkyl, alkoxy, fluoroalkyl or fluoroalkoxy, preferably having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2 - 7 C atoms, preferably alkyl, alkoxy, alkenyl or alkenyloxy, more preferably alkyl, alkenyl, alkoxy or alkenyloxy, and most preferably alkyl, and

[0168] X 1 represents F, Cl, fluoroalkyl, fluoroalkenyl, fluoroalkoxy or fluoroalkenyloxy, the latter four groups preferably having 1 - 4 C atoms, more preferably F, Cl, CF 3 or OCF 3 , and

[0169] f) Again optionally, preferably compulsorily, optionally or additionally, one or more compounds of formula I,

[0170]

[0171] wherein

[0172] denotes

[0173]

[0174]

[0175] denotes

[0176]

[0177] Preferably

[0178]

[0179] n represents 0 or 1,

[0180] R 11 and R 12 each independently of one another represent alkyl, alkoxy, fluoroalkyl or fluoroalkoxy, preferably having 1 - 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2 - 7 C atoms, and preferably alkyl, alkoxy, alkenyl or alkenyloxy, most preferably alkyl, alkoxy or alkenyloxy, and R 11 optionally represents R 1 and R 12 optionally represents X 1 ,

[0181] R 1 represents alkyl, alkoxy, fluoroalkyl or fluoroalkoxy, preferably having 1 to 7 C atoms, preferably alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2 - 7 C atoms, and preferably alkyl or alkenyl, and

[0182] X 1 represents F, Cl, fluoroalkyl, fluoroalkenyl, fluoroalkoxy or fluoroalkenyloxy, the latter four groups preferably having 1 - 4 C atoms, more preferably being F, Cl, CF 3 or OCF 3 , and the compound of formula B is not contained therein.

[0183] Preferably, the medium according to the present application comprises one or more compounds of formula X, which are selected from compounds of formula X - 1 to X - 6, preferably X - 1 and / or X - 3 and / or X - 4,

[0184]

[0185] wherein the parameter

[0186] R represents R 1X ;

[0187] X represents X X ,

[0188] Y 1 、Y 2 and Y 3 represent F, Cl, CF 3 or CHF 2 , preferably one or more of them, most preferably all of them are F, and

[0189] The other parameters have the corresponding meanings given in the above formula X.

[0190] The present invention also relates to compounds of formulae X-4 to X-6.

[0191] More preferably, the medium according to the present application comprises one or more compounds of formula X, wherein the moiety

[0192]

[0193] is selected from the following fractional formulae

[0194]

[0195] wherein

[0196] W represents O or S.

[0197] The liquid crystal medium according to the present application preferably has a nematic phase.

[0198] Throughout the application, in particular R 1 The definition of alkyl means an alkyl group, which can be straight-chain or branched-chain. Each of these groups is preferably straight-chain and preferably has 1, 2, 3, 4, 5, 6, 7 or 8 C atoms, and thus is preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl.

[0199] In the case where alkyl represents a branched-chain alkyl group, it preferably represents 2-alkyl, 2-methylalkyl or 2-(2-ethyl)-alkyl, preferably 2-butyl (=1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, especially 2-methylbutyl, 2-methylbutoxy, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl and 2-dodecyl. The most preferred of these groups are 2-hexyl and 2-octyl.

[0200] The respective branched-chain groups, especially for R 1 , which give rise to chiral compounds, are also referred to as chiral groups in the present application. Particularly preferred chiral groups are 2-alkyl, 2-alkoxy, 2-methylalkyl, 2-methylalkoxy, 2-fluoroalkyl, 2-fluoroalkoxy, 2-(2-ethynyl)-alkyl, 2-(2-ethynyl)-alkoxy, 1,1,1-trifluoro-2-alkyl and 1,1,1-trifluoro-2-alkoxy.

[0201] Particularly preferred chiral groups are, for example, 2-butyl (= 1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, especially 2-methylbutyl, 2-methylbutoxy, 2-methylpentyloxy, 3-methylpentyloxy, 2-ethylhexyloxy, 1-methylhexyloxy, 2-octyloxy, 2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methoxyoctyloxy, 6-methyloctyloxy, 6-methyloctanoyloxy, 5-methylheptoxycarbonyl, 2-methylbutanoyloxy, 3-methylpentanoyloxy, 4-methylhexanoyloxy, 2-chloropropanoyloxy, 2-chloro-3-methylbutanoyloxy, 2-chloro-4-methylpentanoyloxy, 2-chloro-3-methylpentanoyloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl, 1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy, 1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy, 1,1,1-trifluoro-2-octyloxy, 1,1,1-trifluoro-2-octyl, 2-fluoromethyloctyloxy. Very preferred are 2-hexyl, 2-octyl, 2-octyloxy, 1,1,1-trifluoro-2-hexyl, 1,1,1-trifluoro-2-octyl and 1,1,1-trifluoro-2-octyloxy.

[0202] Preferably, the compound of formula X is selected from compounds of formula XA and XB:

[0203]

[0204] wherein the parameters have the corresponding meanings given in formula X above.

[0205] In a preferred embodiment of the present invention, the medium comprises one or more compounds selected from formula XA-1-1 to XA-1-3, XA-2-1 to XA-2-3, XA-3-1 to XA-3-3, XA-4-1 to XA-4-3 and XA-6-1 to XA-6-3

[0206]

[0207]

[0208]

[0209] wherein R X has the meaning of R 1X and R 1X and X X have the corresponding meanings given above.

[0210] Among these compounds, in particular the compounds of formulae XA-4-1 to XA-4-3 and XA-6-1 to XA-6-3 themselves are part of the present invention.

[0211] In a preferred embodiment of the present invention, the medium comprises one or more compounds selected from the compounds of formulae XB-1-1 to XB-1-3, XB-2-1 to XB-2-3, XB-3-1 to XB-3-3, XB-4-1 to XB-4-3 and XB-6-1 to XB-6-3

[0212]

[0213]

[0214]

[0215] wherein R X has the meaning of R 1X and R 1X and X X have the respective meanings given above.

[0216] Among these compounds, in particular the compounds of formulae XB-4-1 to XB-4-3 and XB-6-1 to XB-6-3 themselves are part of the present invention.

[0217] Preferably, the compounds of formula B are selected from the compounds of formulae B-1 and B-2:

[0218]

[0219] wherein

[0220] R 1 represents alkyl, alkoxy, fluoroalkyl or fluoroalkoxy, preferably having 1-7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2-7 C atoms and preferably alkyl or alkenyl, and

[0221] X 1 represents F, Cl, CN, NCS, fluoroalkyl, fluoroalkenyl, fluoroalkoxy or fluoroalkenyloxy, the latter four preferably having 1-4 C atoms, preferably F, Cl, CF 3 or OCF 3 more preferably F, CF 3 or OCF 3 and most preferably OCF 3 or CF 3 .

[0222] Preferably, the compounds of formula I are selected from the compounds of formulae I-1 and I-2:

[0223]

[0224] wherein

[0225] R 11 and R 12 each independently represent alkyl, alkoxy, fluoroalkyl or fluoroalkoxy, preferably having 1 - 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2 - 7 C atoms, and preferably alkyl, alkoxy, alkenyl or alkenyloxy, most preferably alkoxy or alkenyloxy,

[0226] R 1 represents alkyl, alkoxy, fluoroalkyl or fluoroalkoxy, preferably having 1 - 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2 - 7 C atoms, and preferably alkyl or alkenyl, and

[0227] X 1 represents F, Cl, CN, NCS, fluoroalkyl, fluoroalkenyl, fluoroalkoxy or fluoroalkenyloxy, the latter four preferably having 1 - 4 C atoms, preferably F, Cl, CF 3 or OCF 3 , more preferably F, CF 3 or OCF 3 , and most preferably CF 3 or OCF 3 .

[0228] Compounds of general formula X are prepared by methods known per se, as described in the literature (for example in standard works such as Houben - Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Georg - Thieme - Verlag, Stuttgart), specifically under the known and suitable reaction conditions for the said reaction. Variants known per se but not mentioned in more detail herein can be used.

[0229] If desired, the starting materials can also be formed in situ by not separating them from the reaction mixture but immediately further converting them into compounds of general formula X.

[0230] The preferred synthetic routes of the compounds according to the invention are shown in the following scheme and are further illustrated by means of working examples. By choosing suitable starting materials, the synthesis can be adapted to the particular desired compound of general formula I.

[0231] Dibenzofuran derivatives, i.e., compounds of general formula X in which W represents O (formula XA) are synthesized as shown in Scheme 1a and can be obtained by intramolecular substitution of fluorine by nucleophilic attack of a phenolate by treating phenol P with a base.

[0232] Scheme 1a

[0233]

[0234] Alternatively and preferably, the dibenzofuran derivative (Formula XA) is synthesized as shown in Scheme 1b and can be obtained by intramolecular substitution of fluorine by nucleophilic attack of the phenolate by treating phenol P I with base.

[0235] Scheme 1b

[0236]

[0237] The dibenzofuran derivative, i.e., the compound of Formula X where W represents S (Formula XB) is preferably synthesized as shown in Scheme 2.

[0238] Scheme 2

[0239]

[0240] According to Itoh, Takahiro and Mase, Toshiaki, Organic Letters, 6(24), 4587 - 4590; 2004, the intermediate S can be obtained from phenol P (Scheme 1) via the corresponding trifluoromethanesulfonate. Treatment of compound S with a strong non - nucleophilic base, preferably potassium tert - butoxide, gives compound XB (see Jepsen, Tue Heesgaard et al., European Journal of Organic Chemistry, (1), 53 - 57, S53 / 1 - S53 / 65; 2011).

[0241] Therefore, another object of the present invention is the compounds of Formula P and P I in a method for synthesizing a compound of Formula X

[0242]

[0243] where the groups and parameters appearing therein have the meanings given above for Formula X.

[0244] Another object of the present invention is a method for synthesizing a compound of Formula X from a compound of Formula P or P I preferably according to the synthetic routes described in Scheme 1 or Scheme 2 above.

[0245] The reactions described should be considered illustrative only. Those skilled in the art can make corresponding changes to the described synthesis and can also follow other suitable synthetic routes to obtain the compound of Formula X.

[0246] Compounds of general formula X can be used in liquid crystal media. Accordingly, the present invention also relates to a liquid crystal medium comprising two or more liquid crystal compounds, which comprises one or more compounds of general formula X.

[0247] Furthermore, the present invention relates to a liquid crystal display comprising a liquid crystal medium according to the present invention, in particular an IPS or FFS display, particularly preferably an FFS or SG-FFS display.

[0248] Furthermore, the present invention relates to an IPS or FFS type liquid crystal display comprising a liquid crystal cell, said liquid crystal cell consisting of two substrates (wherein at least one substrate is transparent to light and at least one substrate has an electrode layer) and a layer of a liquid crystal medium located between said substrates, said liquid crystal medium comprising a polymeric component and a low molecular weight component, wherein the polymeric component can be obtained by polymerization of one or more polymerizable compounds in the liquid crystal medium between the substrates of the liquid crystal cell, preferably by applying a voltage and wherein the low molecular weight component is a liquid crystal mixture according to the present invention as described in the context.

[0249] The display according to the present invention is preferably addressed by an active matrix (active matrix LCD, abbreviated as AMD), preferably by matrix addressing of thin film transistors (TFT). However, the liquid crystals according to the present invention can also be used in an advantageous manner in displays having other known addressing methods.

[0250] Furthermore, the present invention relates to a method for preparing a liquid crystal medium according to the present invention by mixing one or more compounds of formula X, preferably selected from compounds of formula XA and / or XB, with one or more low molecular weight liquid crystal compounds or liquid crystal mixtures and optionally with other liquid crystal compounds and / or additives.

[0251] The following meanings apply in the context:

[0252] Unless otherwise stated, the term "FFS" is used to denote FFS and SG-FFS displays.

[0253] The term "mesogenic group" is known to those skilled in the art and is described in the literature, and denotes a group that substantially contributes to causing a liquid crystal (LC) phase in low molecular weight or polymeric substances due to the anisotropy of its attractive and repulsive interactions. Compounds containing a mesogenic group (mesogenic compounds) do not necessarily have a liquid crystal phase themselves. Mesogenic compounds can also exhibit liquid crystal phase behavior only after mixing with other compounds and / or after polymerization. Typical mesogenic groups are, for example, rigid rod-like or disc-like units. A review of the terms and definitions used in connection with mesogenic or liquid crystal compounds is given in Pure Appl. Chem. 73(5), 888(2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340 - 6368.

[0254] The term "spacer group" or simply "spacer" (also referred to as "Sp" in the context) is known to those skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 73(5), 888(2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340 - 6368. Unless otherwise stated, the term "spacer group" or "spacer" in the context means a flexible group that connects a mesogenic group and the (one or more) polymerizable groups in a polymerizable mesogenic compound.

[0255] For the purposes of the present invention, the term "liquid crystal medium" is intended to denote a medium comprising a liquid crystal mixture and one or more polymerizable compounds (such as reactive mesogens). The term "liquid crystal mixture" (or "host mixture") is intended to denote a liquid crystal mixture consisting only of non - polymerizable low - molecular - weight compounds, preferably two or more liquid crystal compounds and optionally other additives, such as chiral dopants or stabilizers.

[0256] Liquid crystal mixtures and liquid crystal media having a nematic phase (especially at room temperature) are particularly preferred.

[0257] In a preferred embodiment of the present invention, the liquid crystal medium comprises one or more dielectrically positive compounds having a dielectric anisotropy greater than 3, which are selected from the compounds of formulae II - 1 and II - 2:

[0258]

[0259] where the parameters have the respective meanings described in formula II above, and L 23 and L 24 independently of one another represent H or F, preferably L 23 represents F, and

[0260] has one of the meanings given for

[0261] and, in the case of formulae II - 1 and II - 2, X 2 preferably represents F or OCF 3 , particularly preferably F, and, in the case of formula II - 2,

[0262]

[0263] independently of one another preferably represent

[0264]

[0265] and / or a compound selected from the compounds of formulae III-1 and III-2:

[0266]

[0267] wherein the parameters have the meanings given in formula III,

[0268] and the medium according to the invention, alternatively or in addition to the compounds of formulae III-1 and / or III-2, comprises one or more compounds of formula III-3

[0269]

[0270] wherein the parameters have the respective meanings described above, and the parameter L 31 and L 32 , independently of one another and of the other parameters, represent H or F.

[0271] The liquid-crystalline medium preferably comprises a compound selected from the compounds of formulae II-1 and II-2, wherein L 21 and L 22 and / or L 23 and L 24 both represent F.

[0272] In a preferred embodiment, the liquid-crystalline medium comprises a compound selected from the compounds of formulae II-1 and II-2, wherein L 21 , L 22 , L 23 and L 24 all represent F.

[0273] The liquid-crystalline medium preferably comprises one or more compounds of formula II-1. The compounds of formula II-1 are preferably selected from the compounds of formulae II-1a to II-1e, preferably one or more compounds of formulae II-1a and / or II-1b and / or II-1d, preferably compounds of formula II-1a and / or II-1d or II-1b and / or II-1d, most preferably a compound of formula II-1d:

[0274]

[0275]

[0276] wherein the parameters have the respective meanings described above, and L 25 and L 26 , independently of one another and of the other parameters, represent H or F, and preferably

[0277] in formulae II-1a and II-1b,

[0278] L21 and L 22 both represent F,

[0279] in Formulas II-1c and II-1d,

[0280] L 21 and L 22 both represent F and / or L 23 and L 24 both represent F, and

[0281] in Formula II-1e,

[0282] L 21 , L 22 and L 23 represent F.

[0283] The liquid crystal medium preferably contains one or more compounds of Formula II-2, which are preferably selected from the compounds of Formulas II-2a to II-2k, preferably one or more compounds each of Formulas II-2a and / or II-2h and / or II-2j:

[0284]

[0285]

[0286]

[0287] where the parameters have the respective meanings described above, and L 25 to L 28 , independently of one another, represent H or F, preferably L 27 and L 28 both represent H, particularly preferably L 26 represents H.

[0288] The liquid crystal medium preferably contains a compound selected from the compounds of Formulas II-2a to II-2k, where L 21 and L 22 both represent F and / or L 23 and L 24 both represent F.

[0289] In a preferred embodiment, the liquid crystal medium contains a compound selected from the compounds of Formulas II-2a to II-2k, where L 21 , L 22 , L 23 and L 24 all represent F.

[0290] Particularly preferred compounds of Formula II-2 are compounds of the following formula, particularly preferably Formulas II-2a-1 and / or II-2h-1 and / or II-2k-2:

[0291]

[0292]

[0293]

[0294] wherein R 2 and X 2 have the meanings described above, and X 2 preferably represents F.

[0295] The liquid crystal medium preferably comprises one or more compounds of formula III-1. The compounds of formula III-1 are preferably selected from the compounds of formulae III-1a to III-1j, preferably from formulae III-1c, III-1f, III-1g and III-1j:

[0296]

[0297]

[0298] wherein the parameters have the meanings given above and preferably wherein the parameters have their respective meanings described above, the parameter L 33 and L 34 , independently of each other and independently of the other parameters, represent H or F, and the parameter L 35 and L 36 , independently of each other and independently of the other parameters, represent H or F.

[0299] The liquid crystal medium preferably comprises one or more compounds of formula III-1c, which are preferably selected from the compounds of formulae III-1c-1 to III-1c-5, preferably formula III-1c-1 and / or III-1c-2, most preferably formula III-1c-1:

[0300]

[0301] wherein R 3 has the meaning described above.

[0302] The liquid crystal medium preferably comprises one or more compounds of formula III-1f, which are preferably selected from the compounds of formulae III-1f-1 to III-1f-6, preferably formula III-1f-1 and / or III-1f-2 and / or III-1f-3 and / or III-1f-6, more preferably formula III-1f-3 and / or III-1f-6, even more preferably formula III-1f-6:

[0303]

[0304]

[0305] wherein R 3 has the meaning as described above.

[0306] The liquid crystal medium preferably comprises one or more compounds of formula III-1g, which are preferably selected from the compounds of formula III-1g-1 to III-1g-5, preferably formula III-1g-3:

[0307]

[0308]

[0309] wherein R 3 has the meaning as described above.

[0310] The liquid crystal medium preferably comprises one or more compounds of formula III-1h, which are preferably selected from the compounds of formula III-1h-1 to III-1h-3, preferably formula III-1h-3:

[0311]

[0312] wherein the parameters have the meanings given above, and X 3 preferably represents F.

[0313] The liquid crystal medium preferably comprises one or more compounds of formula III-1i, which are preferably selected from the compounds of formula III-1i-1 and III-1i-2, preferably formula III-1i-2:

[0314]

[0315] wherein the parameters have the meanings given above, and X 3 preferably represents F.

[0316] The liquid crystal medium preferably comprises one or more compounds of formula III-1j, which are preferably selected from the compounds of formula III-1j-1 and III-1j-2, preferably formula III-1j-1:

[0317]

[0318] wherein the parameters have the meanings given above.

[0319] The liquid crystal medium preferably comprises one or more compounds of formula III-2. The compounds of formula III-2 are preferably selected from the compounds of formula III-2a and III-2b, preferably formula III-2b:

[0320]

[0321] wherein the parameters have the respective meanings as described above, and the parameter L 33 and L34 , independently of one another and of the other parameters, represent H or F.

[0322] The liquid crystal medium preferably comprises one or more compounds of formula III-2a, which are preferably selected from the compounds of formulae III-2a-1 to III-2a-6:

[0323]

[0324]

[0325] wherein R 3 has the meanings described above.

[0326] The liquid crystal medium preferably comprises one or more compounds of formula III-2b, which are preferably selected from the compounds of formulae III-2b-1 to III-2b-4, preferably III-2b-4:

[0327]

[0328] wherein R 3 has the meanings described above.

[0329] Instead of or in addition to the compounds of formula III-1 and / or III-2, the medium according to the invention may comprise one or more compounds of formula III-3

[0330]

[0331] where the parameters have the respective meanings described above in formula III.

[0332] These compounds are preferably selected from formulae III-3a and III-3b:

[0333]

[0334] wherein R 3 has the meanings described above.

[0335] The liquid crystal medium according to the invention preferably comprises one or more dielectrically neutral compounds having a dielectric anisotropy of from -1.5 to 3, preferably selected from the compounds of formulae VI, VII, VIII and IX.

[0336] In the present application, all elements include their respective isotopes. In particular, one or more H in the compounds may be replaced by D, and this is also particularly preferred in certain embodiments. The high degree of tritiation of the corresponding compounds can, for example, detect and identify the compounds. This is very useful in certain cases, especially in the case of the compounds of formula I.

[0337] In the present application,

[0338] alkyl preferably represents a straight-chain alkyl group, in particular CH 3 -, C 2 H 5 -, n-C 3 H 7 -, n-C 4 H 9 -, or n-C 5 H 11 -, and

[0339] alkenyl preferably represents CH 2 =CH-, E-CH 3 -CH=CH-, CH 2 =CH-CH 2 -CH 2 -, E-CH 3 -CH=CH-CH 2 -CH 2 -, or E-(n-C 3 H 7 )-CH=CH-.

[0340] In a preferred embodiment of the present invention, in each case the medium according to the present invention comprises one or more compounds of formula VI, which are selected from compounds of formula VI-1 and VI-2, preferably one or more compounds of formula VI-1 each and one or more compounds of formula VI-2,

[0341]

[0342] wherein the parameters have the respective meanings given in formula VI above, and preferably in formula VI-1

[0343] R 61 and R 62 each independently represent methoxy, ethoxy, propoxy, butoxy, or pentyloxy, preferably ethoxy, butoxy or pentyloxy, more preferably ethoxy or butoxy, and most preferably butoxy;

[0344] In formula VI-2

[0345] R 61 preferably represents vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1-en-1-yl or pent-3-en-1-yl and n-propyl or n-pentyl, and

[0346] R 62 represents an unsubstituted alkyl group having 1-7 C atoms, preferably having 2-5 C atoms, or preferably is an unsubstituted alkoxy group having 1-6 C atoms, particularly preferably having 2 or 4 C atoms, and most preferably ethoxy, and

[0347] In a preferred embodiment of the present invention, in each case the medium according to the present invention comprises one or more compounds of formula VII, selected from compounds of formula VII-1 to VII-3, preferably one or more compounds of formula VII-1 each and one or more compounds of formula VII-2,

[0348]

[0349]

[0350] wherein the parameters have their respective meanings as given in formula VII above, and preferably,

[0351] R 71 represents vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1-en-1-yl or pent-3-en-1-yl, n-propyl or n-pentyl and

[0352] R 72 represents an unsubstituted alkyl group having 1-7 C atoms, preferably having 2-5 C atoms, or preferably is an unsubstituted alkoxy group having 1-6 C atoms, particularly preferably having 2 or 4 C atoms, and most preferably ethoxy.

[0353] In a preferred embodiment of the present invention, in each case the medium according to the present invention comprises one or more compounds of formula VI-1, selected from the following compounds:

[0354]

[0355] In a preferred embodiment of the present invention, in each case the medium according to the present invention comprises one or more compounds of formula VI-2, selected from the following compounds:

[0356]

[0357] In a preferred embodiment of the present invention, in each case the medium according to the present invention comprises one or more compounds of formula VII-1, selected from the following compounds:

[0358]

[0359] In a preferred embodiment of the present invention, in each case the medium according to the present invention comprises one or more compounds of formula VII-2, selected from the following compounds:

[0360]

[0361]

[0362] In addition to the compound of formula B or its preferred sub-formula compounds, the medium according to the present invention preferably further comprises one or more dielectrically negative compounds selected from the compounds of formula VI and VII, preferably in a total concentration of 5% or more to 90% or less, preferably 10% or more to 80% or less, particularly preferably 20% or more to 70% or less.

[0363] In a preferred embodiment of the present invention, in each case, the medium according to the present invention comprises one or more compounds of formula VIII selected from the compounds of formula VIII-1 to VIII-3, preferably one or more compounds of formula VIII-1 each and / or one or more compounds of formula VIII-3,

[0364]

[0365] wherein the parameters have their respective meanings as given in formula VIII above, and preferably

[0366] R 81 represents vinyl, 1-E-propenyl, but-4-en-1-yl, pent-1-en-1-yl or pent-3-en-1-yl, ethyl, n-propyl or n-pentyl, an alkyl group, preferably ethyl, n-propyl or n-pentyl and

[0367] R 82 represents an unsubstituted alkyl group having 1-7 C atoms, preferably having 1-5 C atoms, or an unsubstituted alkoxy group having 1-6 C atoms.

[0368] In formulae VIII-1 and VIII-2, R 82 preferably represents an alkoxy group having 2 or 4 C atoms and, most preferably, ethoxy, and in formula VIII-3 it preferably represents an alkyl group, preferably methyl, ethyl or n-propyl, most preferably methyl.

[0369] In a further preferred embodiment, the medium comprises one or more compounds of formula IV, preferably formula IVa,

[0370]

[0371] wherein

[0372] R 41 represents an unsubstituted alkyl group having 1-7 C atoms or an unsubstituted alkenyl group having 2-7 C atoms, preferably an n-alkyl group, particularly preferably having 2, 3, 4 or 5 C atoms, and

[0373] R 42represents an unsubstituted alkyl group having 1 - 7 C atoms, an unsubstituted alkenyl group having 2 - 7 C atoms, or an unsubstituted alkoxy group having 1 - 6 C atoms, all preferably an unsubstituted alkenyl group having 2 - 5 C atoms, preferably having 2, 3 or 4 C atoms, more preferably a vinyl group or a 1 - propenyl group, and particularly a vinyl group.

[0374] In a particularly preferred embodiment, the medium comprises one or more compounds of formula IV selected from compounds of formulae IV - 1 to IV - 4, preferably formula IV - 1

[0375]

[0376]

[0377] wherein

[0378] alkyl and alkyl’ independently of one another represent an alkyl group having 1 - 7 C atoms, preferably having 2 - 5 C atoms,

[0379] alkenyl and alkenyl’ independently of one another represent an alkenyl group having 2 - 5 C atoms, preferably having 2 - 4 C atoms, particularly preferably 2 C atoms,

[0380] alkenyl’ preferably represents an alkenyl group having 2 - 5 C atoms, preferably having 2 - 4 C atoms, particularly preferably having 2 to 3 C atoms, and

[0381] alkoxy represents an alkoxy group having 1 - 5 C atoms, preferably having 2 - 4 C atoms.

[0382] In a particularly preferred embodiment, the medium according to the invention comprises one or more compounds of formula IV - 1 and / or one or more compounds of formula IV - 2.

[0383] In a further preferred embodiment, the medium comprises one or more compounds of formula V.

[0384] The medium according to the invention preferably comprises the following compounds in the indicated total concentration:

[0385] 1 - 60 wt% of one or more compounds selected from compounds of formula X, and

[0386] 1 - 60 wt% of one or more compounds selected from compounds of formula B, and

[0387] 0 - 60 wt% of one or more compounds of formula I, preferably selected from compounds of formulae I - 1 and I - 2, most preferably selected from compounds of formula I - 2, and / or

[0388] 5 - 60 wt% of one or more compounds of formula II, preferably selected from compounds of formula II - 1 and II - 2, and / or

[0389] 5 - 25 wt% of one or more compounds of formula III, and / or

[0390] 5 - 45 wt% of one or more compounds of formula IV, and / or

[0391] 5 - 25 wt% of one or more compounds of formula V, and / or

[0392] 5 - 25 wt% of one or more compounds of formula VI, and / or

[0393] 5 - 20 wt% of one or more compounds of formula VII, and / or

[0394] 5 - 30 wt% of one or more compounds of formula VIII, preferably selected from compounds of formula VIII - 1 and VIII - 2, and / or

[0395] 0 - 60 wt% of one or more compounds of formula IX,

[0396] wherein the total content of all compounds of formula X, formula B, and formulas I to IX present in the medium is preferably 95% or greater, more preferably 97% or higher, and most preferably 100%.

[0397] The latter condition applies to all media according to the present application.

[0398] In a further preferred embodiment, in addition to compounds of formula X or its preferred sub - formulas, and compounds of formula II and / or III and / or VI and / or VII and / or VIII and / or IX and / or I and / or B, the medium according to the invention preferably further comprises one or more dielectrically neutral compounds selected from compounds of formula IV and V, preferably in a total concentration of 5% or greater to 90% or less, preferably 10% or greater to 80% or less, particularly preferably 20% or greater to 70% or less.

[0399] In a particularly preferred embodiment, the medium according to the invention comprises

[0400] one or more compounds of formula X, in a total concentration of 3% or greater to 50% or less, preferably 5% or greater to 30% or less, and

[0401] one or more compounds of formula B, in a total concentration of 3% or greater to 50% or less, preferably 5% or greater to 30% or less, and

[0402] one or more compounds of formula I, in a total concentration of 3% or greater to 50% or less, preferably 5% or greater to 30% or less, and / or

[0403] One or more compounds of formula II, with a total concentration of 5% or greater to 50% or less, preferably 10% or greater to 40% or less, and / or

[0404] One or more compounds of formula VII-1, with a total concentration of 5% or greater to 30% or less, and / or

[0405] One or more compounds of formula VII-2, with a total concentration of 3% or greater to 30% or less.

[0406] Preferably, the concentration of the compound of formula X in the medium according to the present invention is 1% or greater to 60% or less, more preferably 5% or greater to 40% or less, and most preferably 8% or greater to 35% or less.

[0407] Preferably, the concentration of the compound of formula B in the medium according to the present invention is 1% or greater to 60% or less, more preferably 5% or greater to 40% or less, and most preferably 8% or greater to 35% or less.

[0408] In a preferred embodiment of the present invention, the concentration of the compound of formula I in the medium according to the present invention is 1% or greater to 60% or less, more preferably 5% or greater to 40% or less, and most preferably 8% or greater to 35% or less.

[0409] In a preferred embodiment of the present invention, the concentration of the compound of formula II in the medium is 3% or greater to 60% or less, more preferably 5% or greater to 55% or less, more preferably 10% or greater to 50% or less, and most preferably 15% or greater to 45% or less.

[0410] In a preferred embodiment of the present invention, the concentration of the compound of formula VII in the medium is 2% or greater to 50% or less, more preferably 5% or greater to 40% or less, more preferably 10% or greater to 35% or less, and most preferably 15% or greater to 30% or less.

[0411] In a preferred embodiment of the present invention, the concentration of the compound of formula VII-1 in the medium is 1% or greater to 40% or less, more preferably either 2% or greater to 35% or less or alternatively 15% or greater to 25% or less.

[0412] In a preferred embodiment of the present invention, the concentration of the compound of formula VII-2 in the medium, if present, is 1% or greater to 40% or less, more preferably 5% or greater to 35% or less, and most preferably 10% or greater to 30% or less.

[0413] The invention also relates to an electro-optical display or electro-optical component which comprises a liquid-crystalline medium according to the invention. Electro-optical displays based on the VA, ECB, IPS or FFS effect are preferred, preferably based on the VA, IPS or FFS effect, and in particular those addressed by active matrix addressing devices.

[0414] Accordingly, the invention also relates to the use of a liquid-crystalline medium according to the invention in an electro-optical display or electro-optical component, and to a process for preparing a liquid-crystalline medium according to the invention, characterized in that one or more compounds of formula B are mixed with one or more compounds of formula I, preferably with one or more compounds of sub-formulae I-1 and / or I-2, preferably with a compound of formula I-2, and / or with one or more compounds of formula II, preferably with one or more compounds of sub-formulae II-1 and / or II-2, with one or more compounds of formula VII, preferably with one or more compounds of sub-formulae VII-1 and / or VII-2, very particularly preferably two or more, preferably three or more and very particularly preferably all four of one or more compounds of different ones of these formulae II-1, II-2, VII-1 and VII-2 and one or more further compounds, preferably compounds selected from formulae IV and V, more preferably with one or more compounds of formula IV and formula V.

[0415] In a further preferred embodiment, the medium comprises one or more compounds of formula IV selected from compounds of formulae IV-2 and IV-3,

[0416]

[0417] wherein

[0418] alkyl and alkyl’ independently of one another denote an alkyl group having 1-7 C atoms, preferably having 2-5 C atoms,

[0419] alkoxy denotes an alkoxy group having 1-5 C atoms, preferably having 2-4 C atoms.

[0420] In a further preferred embodiment, the medium comprises one or more compounds of formula V selected from formulae V-1 and V-2, preferably a compound of formula V-1,

[0421]

[0422] where the parameters have the meanings given in formula V above, and preferably

[0423] R 51 denotes an alkyl group having 1-7 C atoms or an alkenyl group having 2-7 C atoms, and

[0424] R 52represents an alkyl group having 1 - 7 C atoms, an alkenyl group having 2 - 7 C atoms, or an alkoxy group having 1 - 6 C atoms, preferably an alkyl or alkenyl group, particularly preferably an alkyl group.

[0425] In a further preferred embodiment, the medium comprises one or more compounds of formula V - 1 selected from compounds of formula V - 1a and V - 1b,

[0426]

[0427] wherein

[0428] alkyl and alkyl’ independently of one another represent an alkyl group having 1 - 7 C atoms, preferably having 2 - 5 C atoms, and

[0429] alkenyl represents an alkenyl group having 2 - 7 C atoms, preferably having 2 - 5 C atoms.

[0430] Furthermore, the present invention relates to a method for reducing the birefringence wavelength dispersion of a liquid crystal medium, the liquid crystal medium comprising one or more compounds of formula II, optionally one or more compounds selected from compounds of formula VII - 1 and VII - 2 and / or one or more compounds of formula IV and / or one or more compounds of formula V, characterized in that one or more compounds of formula B are used for the medium.

[0431] In addition to the compounds of formulae X, B and I to IX, other components may also be present, for example in an amount of at most 45%, but preferably at most 35%, in particular at most 10%, based on the entire mixture.

[0432] The medium according to the invention may also optionally comprise a dielectrically positive component, the total concentration of which is preferably 20% or less, more preferably 10% or less, based on the entire medium.

[0433] In a preferred embodiment, based on the entire mixture, the liquid crystal medium according to the invention comprises in total:

[0434] from 1% or more to 20% or less, preferably from 2% or more to 15% or less, particularly preferably from 3% or more to 12% or less of a compound of formula X, and / or

[0435] from 1% or more to 20% or less, preferably from 2% or more to 15% or less, particularly preferably from 3% or more to 12% or less of a compound of formula B, and / or

[0436] from 1% or more to 20% or less, preferably from 2% or more to 15% or less, particularly preferably from 3% or more to 12% or less of a compound of formula I, and / or

[0437] From 20% or greater to 50% or less, preferably from 25% or greater to 45% or less, particularly preferably from 30% or greater to 40% or less of the compound of formula II and / or III, and / or

[0438] From 0% or greater to 35% or less, preferably from 2% or greater to 30% or less, particularly preferably from 3% or greater to 25% or less of the compound of formula IV and / or V, and / or

[0439] From 5% or greater to 50% or less, from 10% or greater to 45% or less, preferably from 15% or greater to 40% or less of the compound of formula VI and / or VII and / or VIII and / or IX.

[0440] The liquid crystal medium according to the invention may comprise one or more chiral compounds.

[0441] Particularly preferred embodiments of the invention meet one or more of the following conditions:

[0442] wherein the abbreviations (acronyms) are explained in Tables A to C and illustrated by examples in Table D.

[0443] The medium according to the invention preferably meets one or more of the following conditions.

[0444] i. The liquid crystal medium has a birefringence of 0.060 or greater, particularly preferably 0.070 or greater.

[0445] ii. The liquid crystal medium has a birefringence of 0.200 or less, particularly preferably 0.180 or less.

[0446] iii. The liquid crystal medium has a birefringence from 0.090 or greater to 0.160 or less.

[0447] iv. The liquid crystal medium comprises one or more particularly preferred compounds of formula X, preferably selected from (sub-)formulas XA and XB, most preferably selected from (sub-)formulas XA-2-5 and / or XB-2-5.

[0448] v. The liquid crystal medium comprises one or more particularly preferred compounds of formula B, preferably selected from the sub-formulas B-1 and B-2 compounds, more preferably selected from the sub-formula B-2.

[0449] vi. The liquid crystal medium comprises one or more particularly preferred compounds of formula I, preferably selected from the sub-formulas I-1 and I-2 compounds, more preferably selected from the sub-formula I-2.

[0450] vii. The total concentration of the compound of formula II in the entire mixture is 25% or greater, preferably 30% or greater, and preferably from 25% or greater to 49% or less, particularly preferably from 29% or greater to 47% or less, and very particularly preferably from 37% or greater to 44% or less.

[0451] viii. The liquid crystal medium contains one or more type IV compounds selected from the compounds of the following formula: CC-n-V and / or CC-n-Vm and / or CC-V-V and / or CC-V-Vn and / or CC-nV-Vn, particularly preferably CC-3-V, preferably at a concentration of at most 60% or less, particularly preferably at most 50% or less, and optionally additionally CC-3-V1, preferably at a concentration of at most 15% or less, and / or CC-4-V, preferably at a concentration of at most 40% or less, particularly preferably at most 30% or less.

[0452] ix. The medium contains a compound of formula CC-n-V, preferably CC-3-V, preferably at a concentration of 1% or greater to 60% or less, more preferably at a concentration of 3% or greater to 35% or less.

[0453] x. The total concentration of the compound of formula CC-3-V in the entire mixture is preferably 15% or less, preferably 10% or less or 20% or greater, preferably 25% or greater.

[0454] xi. The total concentration of the compound of formula Y-nO-Om in the entire mixture is 2% or greater to 30% or less, preferably 5% or greater to 15% or less.

[0455] xii. The total concentration of the compound of formula CY-n-Om in the entire mixture is 5% or greater to 60% or less, preferably 15% or greater to 45% or less.

[0456] xiii. The total concentration of the compound of formula CCY-n-Om and / or CCY-n-m, preferably CCY-n-Om in the entire mixture is 5% or greater to 40% or less, preferably 1% or greater to 25% or less.

[0457] xiv. The total concentration of the compound of formula CLY-n-Om in the entire mixture is 5% or greater to 40% or less, preferably 10% or greater to 30% or less.

[0458] xv. The liquid crystal medium contains one or more type IV compounds, preferably type IV-1 and / or IV-2 compounds, preferably at a total concentration of 1% or greater, particularly 2% or greater, and very particularly preferably 3% or greater to 50% or less, preferably 35% or less.

[0459] xvi. The liquid crystal medium contains one or more type V compounds, preferably type V-1 and / or V-2 compounds, preferably at a total concentration of 1% or greater, particularly 2% or greater, and very particularly preferably 15% or greater to 35% or less, preferably up to 30% or less.

[0460] xvii. The total concentration of the CCP-V-n compound, preferably CCP-V-1, in the entire mixture is preferably 5% or more to 30% or less, more preferably 15% or more to 25% or less.

[0461] xviii. The total concentration of the CCP-V2-n compound, preferably CCP-V2-1, in the entire mixture is preferably 1% or more to 15% or less, more preferably 2% or more to 10% or less.

[0462] The present invention further relates to an electro-optical display with active matrix addressing based on VA, ECB, IPS, FFS or UB-FFS effects, characterized in that it contains a liquid crystal medium according to the invention as a dielectric.

[0463] The liquid crystal mixture preferably has a nematic phase range with a width of at least 70 degrees.

[0464] Rotational viscosity γ 1 Preferably 350 mPa·s or less, more preferably 250 mPa·s or less and particularly 150 mPa·s or less.

[0465] The mixtures according to the invention are suitable for all IPS and FFS-TFT applications using a dielectrically positive liquid crystal medium, such as SG-FFS.

[0466] The liquid crystal medium according to the invention preferably consists essentially of 4 - 15, particularly 5 - 12, and very particularly preferably 10 or fewer compounds. These are preferably selected from compounds of the formulas X, B, I, II, III, IV, V, VI, VII, VIII and IX.

[0467] The liquid crystal medium according to the invention may also optionally contain more than 18 compounds. In this case, they preferably contain 18 - 25 compounds.

[0468] In a preferred embodiment, the liquid crystal medium according to the invention mainly comprises, preferably consists essentially of and most preferably consists essentially of compounds that do not contain a cyano group.

[0469] In a preferred embodiment, the liquid crystal medium according to the invention contains compounds selected from the compounds of the formulas X, B, I, II and II, IV and V and VI to IX, preferably selected from the compounds of the formulas XA, XB, B-1, B-2, I-1, I-2, II-1, II-2, III-1, III-2, IV, V, VII-1, VII-2, VIII and IX; they preferably mainly consist of, particularly preferably consist essentially of and very particularly preferably consist essentially of the compounds of said formulas.

[0470] The liquid crystal medium according to the present invention preferably has a nematic phase of at least -10 °C or less to 70 °C or more, particularly preferably -20 °C or less to 80 °C or more, very particularly preferably -30 °C or less to 85 °C or more, and most preferably -40 °C or less to 90 °C or more in various cases.

[0471] The expression "having a nematic phase" herein means on the one hand that no smectic phase and crystallization are observed at low temperatures at the corresponding temperature, and on the other hand that no clearing occurs when heating from the nematic phase. The study at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storing in a test cell having a cell thickness corresponding to at least 100 hours of electro-optical application. If the storage stability at a temperature of -20 °C in the corresponding test cell is 1,000 h or longer, the medium is considered stable at this temperature. At temperatures of -30 °C and -40 °C, the corresponding times are 500 h and 250 h, respectively. At high temperatures, the clearing point is measured in a capillary by a conventional method.

[0472] In a preferred embodiment, the liquid crystal medium according to the present invention is characterized by an optical anisotropy value in the moderate to low range. The birefringence value is preferably 0.075 or more to 0.130 or less, particularly preferably 0.085 or more to 0.120 or less, and very particularly preferably 0.090 or more to 0.115 or less.

[0473] In this embodiment, the liquid crystal medium according to the present invention has a positive dielectric anisotropy and a relatively high absolute value of dielectric anisotropy Δε, which is preferably 2.0 or more to 20 or less, more preferably up to 15 or less, more preferably 3.0 or more to 10 or less, particularly preferably 4.0 or more to 9.0 or less, and very particularly preferably 4.5 or more to 8.0 or less.

[0474] The liquid crystal medium according to the present invention preferably has a relatively low threshold voltage (V 0 ) value, which ranges from 1.0 V or higher to 5.0 V or lower, preferably up to 2.5 V or lower, preferably 1.2 V or higher to 2.2 V or lower, particularly preferably 1.3 V or higher to 2.0 V or lower.

[0475] In a further preferred embodiment, the liquid crystal medium according to the present invention preferably has a relatively high average dielectric constant value (ε av. ≡(ε || +2ε ⊥ ) / 3), which is preferably 8.0 or more to 25.0 or less, preferably 8.5 or more to 20.0 or less, still more preferably 9.0 or more to 19.0 or less, particularly preferably 10.0 or more to 18.0 or less, and very particularly preferably 11.0 or more to 16.5 or less.

[0476] In addition, the liquid crystal medium according to the invention has a high VHR value in the liquid crystal cell.

[0477] In a freshly filled cell at 20 °C, in the cell, the VHR values of these media are greater than or equal to 95%, preferably greater than or equal to 97%, particularly preferably greater than or equal to 98% and very particularly preferably greater than or equal to 99%, and after 5 minutes in an oven at 100 °C, in the cell, these values are greater than or equal to 90%, preferably greater than or equal to 93%, particularly preferably greater than or equal to 96% and very particularly preferably greater than or equal to 98%.

[0478] Generally, a liquid crystal medium having a low addressing voltage or threshold voltage here has a lower VHR compared to those having a higher addressing voltage or threshold voltage, and vice versa.

[0479] These preferred values of the respective physical properties are also preferably maintained by combining the media according to the invention with each other in various cases.

[0480] In this application, the term "compound (compounds)", also written as "one or more compounds (compounds)", refers to both single and multiple compounds, unless otherwise expressly stated.

[0481] In a preferred embodiment, the liquid crystal medium according to the invention comprises

[0482] one or more compounds of formula X, and

[0483] one or more compounds of formula B, preferably selected from compounds of formula CB-n-F, CB-n-OT, CB-n-T, LB-n-F, LB-n-OT and LB-n-T, more preferably selected from compounds of formula CB-n-OT, CB-n-T, LB-n-OT and LB-n-T, preferably selected from compounds of formula CB-n-OT, CB-n-T, and / or

[0484] one or more compounds of formula I, preferably selected from compounds of formula B-nO-Om, B(S)-nO-Om, B-nO-OT, B-nO-T, B-n-OT and B-n-F, more preferably selected from compounds of formula B-nO-OT, B-nO-T, B-n-OT and B-n-F, and / or

[0485] one or more compounds of formula II, preferably selected from compounds of formula PUQU-n-F, CDUQU-n-F, APUQU-n-F and PGUQU-n-F, and / or

[0486] one or more compounds of formula III, preferably selected from compounds of formula CCP-n-OT, CGG-n-F and CGG-n-OD, and / or

[0487] One or more compounds of formula IV and / or V, preferably selected from formulae CC-n-V, CCP-n-m, CCP-V-n, CCP-V2-n and CGP-n-n and / or,

[0488] One or more compounds of formula VI, preferably formula Y-n-Om, Y-nO-Om and / or CY-n-Om, selected from compounds of formula Y-3-O1, Y-4O-O4, CY-3-O2, CY-3-O4, CY-5-O2 and CY-5-O4, and / or

[0489] Optionally, preferably compulsorily, one or more compounds of formula VII-1, preferably selected from compounds of formula CCY-n-m and CCY-n-Om, preferably formula CCY-n-Om, preferably selected from compounds of formula CCY-3-O2, CCY-2-O2, CCY-3-O1, CCY-3-O3, CCY-4-O2, CCY-3-O2 and CCY-5-O2, and / or

[0490] Optionally, preferably compulsorily, one or more compounds of formula VII-2, preferably formula CLY-n-Om, preferably selected from compounds of formula CLY-2-O4, CLY-3-O2, CLY-3-O3, and / or

[0491] One or more compounds of formula VIII, preferably selected from formulae CZY-n-On and CCOY-n-m and / or

[0492] One or more compounds of formula IX, preferably selected from formulae PYP-n-m, PYP-n-mVI and PYP-n-mVI, preferably selected from compounds of formula PYP-2-3, PYP-2-4, PYP-2-5, PYP-2-V and PYP-2-2V1, and / or

[0493] One or more compounds selected from formulae PGP-n-m, PGP-n-V, PGP-n-Vm, PGP-n-mV and PGP-n-mVl, preferably selected from compounds of formula PGP-2-3, PGP-2-4, PGP-2-5, PGP-1-V, PGP-2-V and PGP-2-2V1, and / or

[0494] Optionally, preferably compulsorily, one or more compounds of formula IV, preferably selected from compounds of formula CC-n-V, CC-n-Vm, CC-n-mVI and CC-nV-Vm, preferably CC-3-V, CC-3-V1, CC-4-V, CC-5-V, CC-3-2V1 and CC-V-V, particularly preferably selected from compounds CC-3-V, CC-3-V1, CC-4-V, CC-3-2V1 and CC-V-V, very particularly preferably compound CC-3-V, and optionally further compounds CC-4-V and / or CC-3-V1 and / or CC-3-2V1 and / or CC-V-V, and / or

[0495] Optionally, preferably compulsorily, one or more compounds of formula V, preferably selected from formula CCP-V-1 and / or CCP-V2-1.

[0496] In a particularly preferred embodiment of the invention, the medium according to the invention comprises one or more compounds of formula IX,

[0497] Compounds of formula IX are also highly suitable as stabilizers in liquid crystal mixtures, especially in the case where p = q = 1 and ring A 9 = 1,4-phenylene. In particular, they stabilize the mixture against VHR upon UV exposure.

[0498] In a preferred embodiment, the medium according to the invention comprises one or more compounds of formula IX selected from one or more compounds of formulae IX-1 to IX-4, very particularly preferably formulae IX-1 to IX-3,

[0499]

[0500] where the parameters have the meanings given in formula IX.

[0501] In a further preferred embodiment, the medium comprises one or more compounds of formula IX-3, preferably formula IX-3-a,

[0502]

[0503] where

[0504] alkyl and alkyl’ independently of one another represent an alkyl group having 1-7 C atoms, preferably having 2-5 C atoms,

[0505] When compounds of formula IX are used in the liquid crystal medium according to the present application, they are preferably present in a concentration of 20% or less, more preferably 10% or less and most preferably 5% or less and for each (homologous) compound the preferred concentration is 10% or less and more preferably 5% or less.

[0506] For the present invention, the following definitions are applied to describe the composition of the composition, unless otherwise specified in each case:

[0507] - "comprising": the concentration of the component under discussion in the composition is preferably 5% or greater, particularly preferably 10% or greater, and very particularly preferably 20% or greater,

[0508] - "consisting essentially of": the concentration of the component under discussion in the composition is preferably 50% or greater, particularly preferably 55% or greater and very particularly preferably 60% or greater,

[0509] - "consisting essentially of": the concentration of the component under discussion in the composition is preferably 80% or greater, particularly preferably 90% or greater and very particularly preferably 95% or greater, and

[0510] - "consisting essentially of": the concentration of the component under discussion in the composition is preferably 98% or greater, particularly preferably 99% or greater and very particularly preferably 100.0%.

[0511] This applies both to the medium as a composition having its components (which may be components and compounds), and also to the components having their components (compounds). Only when referring to the concentration of the individual compounds relative to the entire medium, the term "comprising" means: the concentration of the compound under discussion is preferably 1% or greater, particularly preferably 2% or greater, and very particularly preferably 4% or greater.

[0512] For the present invention, "≤" means less than or equal to, preferably less than, and "≥" means greater than or equal to, preferably greater than.

[0513] For the present invention,

[0514]

[0515] represents trans-1,4-cyclohexylene,

[0516]

[0517] represents a mixture of both cis-1,4-cyclohexylene and trans-1,4-cyclohexylene, and

[0518]

[0519] represents 1,4-phenylene.

[0520] For the present invention, the expression "dielectrically positive compound" means a compound having Δε > 1.5, the expression "dielectrically neutral compound" means those in which -1.5 ≤ Δε ≤ 1.5 and the expression "dielectrically negative compound" means those in which Δε < -1.5. The dielectric anisotropy of the compounds here is determined by dissolving 10% of the compound in a liquid-crystal host and measuring the capacitance of the resulting mixture in each case in a test cell having a cell thickness of 20 μm with homeotropic surface alignment and in-plane surface alignment at 1 kHz. The measurement voltage is generally from 0.5 V to 1.0 V, but always below the capacitance threshold of the respective liquid-crystal mixtures under investigation.

[0521] The host mixture for the dielectrically positive and dielectrically neutral compounds is ZLI-4792 and the host mixture for the dielectrically negative compounds is ZLI-2857, both from Merck KGaA, Germany. The values of the respective compounds to be investigated are obtained from the change in the dielectric constant of the host mixture after addition of the compound to be investigated and extrapolation to 100% of the compound employed. The compound to be investigated 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 halved step by step until the investigation can be carried out at the desired temperature.

[0522] If necessary, the liquid-crystal medium according to the invention can also contain other additives, such as stabilizers and / or pleochroic dyes, such as dichroic dyes and / or chiral dopants, in customary amounts. The amounts of these additives employed preferably total from 0% or more to 10% or less, based on the amount of the entire mixture, particularly preferably from 0.1% or more to 6% or less. The concentration of each of the compounds employed is preferably from 0.1% or more to 3% or less. When specifying the concentration and concentration ranges of the liquid-crystal compounds in the liquid-crystal medium, the concentration of these and similar additives is generally not taken into account.

[0523] In a preferred embodiment, the liquid-crystal medium according to the invention contains a polymer precursor which contains one or more reactive compounds, preferably reactive mesogens, and, if desired, also further contains other additives, such as polymerization initiators and / or polymerization moderators, in customary amounts. The amounts of these additives employed total from 0% or more to 10% or less, preferably from 0.1% or more to 2% or less, based on the amount of the entire mixture. When specifying the concentration and concentration ranges of the liquid-crystal compounds in the liquid-crystal medium, the concentration of these and similar additives is not taken into account.

[0524] The composition consists of a plurality of compounds, preferably 3 or more to 30 or fewer, particularly preferably 6 or more to 20 or fewer and very particularly preferably 10 or more to 16 or fewer compounds, which are mixed in a conventional manner. Generally, the components used in smaller amounts in the desired amounts are dissolved in the components that make up the main components of the mixture. This is advantageously carried out at an elevated temperature. If the selected temperature is higher than the clearing point of the main component, it is particularly easy to observe the completion of the dissolution operation. However, the liquid crystal mixture can also be prepared in other conventional ways, such as using premixing or preparing from a so-called "multi-bottle system".

[0525] The mixtures according to the invention exhibit a very wide nematic range with a clearing point of 65 °C or higher, very favorable capacitance thresholds, relatively high retention rate values and at the same time very good low-temperature stability at -30 °C and -40 °C. In addition, the mixtures according to the invention are characterized by a low rotational viscosity γ 1 。

[0526] It goes without saying to those skilled in the art that the media according to the invention for VA, IPS, FFS or PALC displays can also contain compounds in which, for example, H, N, O, Cl, F have been replaced by the corresponding isotopes.

[0527] The structure of the liquid crystal display according to the invention corresponds to a general geometry, as described, for example, in EP-A 0 240 379.

[0528] The liquid crystal phases according to the invention can be varied by suitable additives in such a way that they can be used in any type of LCD display disclosed hitherto, such as IPS and FFS LCD displays.

[0529] Table E below indicates the possible dopants that can be added to the mixtures according to the invention. If the mixture contains one or more dopants, they are used in an amount of 0.01% to 4%, preferably 0.1% to 1.0%.

[0530] For example, the stabilizers that can be added to the mixtures according to the invention in an amount of preferably 0.01% to 6%, particularly 0.1% to 3% are shown in Table F below.

[0531] For the purposes of the present invention, unless otherwise expressly stated, all concentrations are expressed in weight percentages and, unless otherwise expressly stated, all concentrations are relative to the entire corresponding mixture or relative to the entire respective mixture components. In the context, the term "mixture" describes the liquid crystal medium.

[0532] Unless otherwise explicitly stated, all temperature values described in this application, such as the melting point T(C,N), the transition from the smectic (S) phase to the nematic (N) phase T(S,N), and the clearing point T(N,I), are expressed in degrees Celsius (°C) and all temperature differences are accordingly expressed in differential degrees (° or degrees).

[0533] For the present invention, the term "threshold voltage" refers to the capacitive threshold (V 0 ), also known as the Freedericks-threshold, unless otherwise explicitly stated.

[0534] All physical properties are and have been determined in accordance with "Merck Liquid Crystals, physical properties of Liquid Crystals", Status November 1997, Merck KGaA (Germany), and apply to a temperature of 20 °C, with Δn measured at 436 nm, 589 nm and 633 nm, and Δε measured at 1 kHz, unless otherwise explicitly stated in each case.

[0535] Electro-optical properties, such as the threshold voltage (V 0 )(capacitive measurement) (which is the switching behavior) are measured in a test cell manufactured by Merck Japan. The measurement cell has soda-lime glass substrates and is constructed in an ECB or VA configuration with a polyimide alignment layer (with diluent ** 26 of SE-1211 (mixing ratio 1:1), both from Nissan Chemicals, Japan), which have been rubbed perpendicular to each other and affect the homeotropic alignment of the liquid crystal. The surface area of the transparent, almost square ITO electrodes is 1 cm 2 .

[0536] Unless otherwise stated, no chiral dopant is added to the liquid crystal mixtures used, but the latter are also particularly suitable for applications in which this type of doping is necessary.

[0537] The rotational viscosity is measured using the rotating permanent magnet method and the flow viscosity is measured in a modified Ubbelohde viscometer. For the liquid crystal mixtures ZLI-2293, ZLI-4792 and MLC-6608 (all products from Merck KGaA, Darmstadt, Germany), the rotational viscosity values measured at 20 °C are 161 mPa·s, 133 mPa·s and 186 mPa·s, respectively, and the flow viscosity values (ν) are 21 mm 2 ·s -1 , 14 mm 2 ·s -1 and 27 mm 2 ·s -1。

[0538] For practical purposes, the dispersion of the material may be conveniently characterized in the following manner, which is used throughout the application unless otherwise explicitly stated. The birefringence values are determined at several fixed wavelengths at a temperature of 20 °C using a modified Abbe refractometer, where the surface with homeotropic alignment is in contact with the material on the side of the prism. The birefringence values are determined at specific wavelength values of 436 nm (each selected spectral line of a low-pressure mercury lamp), 589 nm (sodium "D" line), and 633 nm (wavelength of a He-Ne laser, which is used in combination with an attenuator / diffuser to prevent damage to the observer's eyes). In the following table, Δn is given at 589 nm and Δ(Δn) is given as Δ(Δn) = Δn(436 nm) - Δn(633 nm).

[0539] Unless otherwise explicitly stated, the following symbols are used:

[0540] V 0 Threshold voltage, capacitive [V], at 20 °C,

[0541] n e Extraordinary refractive index measured at 20 °C and 589 nm,

[0542] n o Ordinary refractive index measured at 20 °C and 589 nm,

[0543] Δn Optical anisotropy measured at 20 °C and 589 nm,

[0544] λ Wavelength λ [nm],

[0545] Δn(λ) Optical anisotropy measured at 20 °C and wavelength λ,

[0546] Δ(Δn) Change in optical anisotropy, defined as:

[0547] Δn(20 °C, 436 nm) - Δn(20 °C, 633 nm),

[0548] Δ(Δn * ) "Relative change in optical anisotropy", defined as:

[0549] Δ(Δn) / Δn(20 °C, 589 nm),

[0550] ε ⊥ Dielectric polarizability perpendicular to the director at 20 °C and 1 kHz,

[0551] ε || Dielectric polarizability parallel to the director at 20 °C and 1 kHz,

[0552] Δε Dielectric anisotropy at 20 °C and 1 kHz,

[0553] T(N,I) or clp. clearing point [°C],

[0554] ν Kinematic viscosity measured at 20 °C [mm 2 ·s -1 ,

[0555] γ 1 Rotational viscosity measured at 20 °C [mPa·s],

[0556] k 11 Elastic constant, "tilt" deformation at 20 °C [pN],

[0557] k 22 Elastic constant, "twist" deformation at 20 °C [pN],

[0558] k 33 Elastic constant, "bend" deformation at 20 °C [pN],

[0559] LTS Low temperature stability of the phase, measured in the test cell,

[0560] VHR Voltage holding ratio,

[0561] ΔVHR Decrease in voltage holding ratio, and

[0562] S rel Relative stability of VHR.

[0563] The following examples illustrate the invention, but do not limit it. However, they show to those skilled in the art the concept of using the preferred compounds to be employed and their respective concentrations and preferred mixtures thereof in combination with each other. In addition, the examples illustrate the properties and combinations of properties that can be obtained.

[0564] For the present invention and in the following examples, the structures of the liquid crystal compounds are represented by abbreviations and converted into chemical formulas according to Tables A to C below. 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 2lis a straight-chain alkyl group or an alkylene group, each having n, m, and l carbon atoms in each case. Preferably, n, m, and l are each independently 1, 2, 3, 4, 5, 6, or 7. Table A shows the codes for the ring elements of the compound nucleus, Table B lists the bridging units, and Table C lists the symbolic meanings of the left- and right-hand end groups of the molecule. The abbreviations consist of the code for the ring element with an optional linking group, followed by a first hyphen and the left-hand end group code, and a second hyphen and the right-hand end group code. Table D shows the exemplary structures of the compounds and their respective abbreviations.

[0565] Table A: Ring elements

[0566]

[0567]

[0568]

[0569]

[0570] Table B: Bridging units

[0571]

[0572] Table C: End groups

[0573]

[0574]

[0575]

[0576] where n and m are each integers, and the three dots "..." are placeholders for other abbreviations from the table.

[0577] In addition to the compounds of formula B, the mixtures according to the invention preferably further comprise one or more, preferably four, five, six or more of the following-mentioned compounds, preferably selected from two, three, four, five or more different ones of these formulas.

[0578] The following abbreviations are used, where:

[0579] n, m, k, and l are each independently integers, preferably 1 - 9, more preferably 1 - 7, k and l may also be 0 and are preferably 0 - 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, 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 "-IVm" is preferably "2V1".

[0580] Table D

[0581] Exemplary preferred Compound of Formula X

[0582]

[0583] Exemplary preferred having high ε ⊥ of Compound of Formula B:

[0584]

[0585] Exemplary preferred having high ε ⊥ of Compound of Formula I:

[0586]

[0587]

[0588]

[0589]

[0590]

[0591] Exemplary preferred dielectric positive compounds

[0592]

[0593]

[0594]

[0595]

[0596]

[0597]

[0598]

[0599]

[0600] Exemplary preferred dielectrically neutral compounds

[0601]

[0602]

[0603]

[0604]

[0605]

[0606]

[0607] Exemplary preferred dielectrically negative compounds

[0608]

[0609]

[0610]

[0611]

[0612]

[0613]

[0614]

[0615]

[0616]

[0617] Table E shows the chiral dopants preferably employed in the mixtures according to the invention.

[0618] Table E

[0619]

[0620]

[0621]

[0622] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds selected from the compounds of Table E.

[0623] Table F shows stabilizers that can preferably also be employed in the mixtures according to the invention in addition to the compounds of formula B. Here, the parameter n represents an integer from 1 to 12. In particular, the phenolic derivatives shown can be employed as additional stabilizers since they act as antioxidants.

[0624] Table F

[0625]

[0626]

[0627]

[0628]

[0629]

[0630] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds selected from the compounds of Table F, in particular one or more compounds selected from the compounds of the following two formulas

[0631] Examples

[0632] The following examples illustrate the invention without in any way limiting it. However, the physical properties make it clear to the person skilled in the art what properties can be achieved and in which ranges they can be adjusted. In particular, combinations of the various properties that can preferably be achieved by the person skilled in the art are thus well defined.

[0633] Synthesis examples

[0634] Synthesis example 1: Synthesis of 2,4-difluoro-7-(4-n-propylcyclohex-1-en-1-yl)-3-(trifluoromethyl) dibenzofuran (1)

[0635]

[0636] Step 1.1: 1-(4-bromo-3-fluoro-phenyl)-4-propyl-cyclohexanol

[0637]

[0638] A solution of 1-bromo-2-fluoro-4-iodobenzene (CAS-no. 136434-77-0, 40.2 g, 134 mmol) in THF (250 mL) was cooled to -5 °C, and then a solution of isopropylmagnesium chloride (2 mol / L in THF, 68 mL, 136 mmol) and THF (100 mL) was added dropwise. The reaction mixture was stirred at 0 °C for 90 minutes. Then a solution of 4-propylcyclohexanone (CAS-no. 40649-36-3, 19.1 g, 136 mmol) in THF (50 mL) was added dropwise at 0 °C, and the reaction mixture was slowly warmed to room temperature and stirred for 3 hours. The reaction mixture was hydrolyzed with ice water, diluted with MTB ether and acidified with hydrochloric acid (2N). The aqueous phase was separated and extracted with MTB ether. The combined organic phases were washed with brine, dried (sodium sulfate) and concentrated in vacuo. 1-(4-Bromo-3-fluorophenyl)-4-propyl-cyclohexanol was isolated as a yellow oil.

[0639] Step 1.2: 1-Bromo-2-fluoro-4-(4-propylcyclohex-1-en-1-yl)benzene

[0640]

[0641] A mixture of 1-(4-bromo-3-fluorophenyl)-4-propyl-cyclohexanol (44 g, 97 mmol) and toluene-4-sulfonic acid monohydrate (1.5 g, 8 mmol) in toluene (400 mL) was heated at reflux temperature for 2 hours. Then it was cooled to room temperature, neutralized with sodium hydroxide solution (2N) and diluted with water. The aqueous phase was separated and extracted with toluene. The combined organic phases were dried (sodium sulfate) and concentrated in vacuo. The residue was purified by silica gel chromatography (solvent: n-heptane) to give 1-bromo-2-fluoro-4-(4-propylcyclohex-1-en-1-yl)benzene as a colorless oil.

[0642] Step 1.3: [2-Fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]boronic acid

[0643]

[0644] A solution of 1-bromo-2-fluoro-4-(4-propylcyclohex-1-en-1-yl)benzene (80 g, 245 mmol) in THF (650 mL) was cooled to -65 °C, and then a solution of butyllithium (175 mL, 279 mmol) was added dropwise at -60 °C and stirred for 1 h. A solution of trimethyl borate (31 mL, 273 mmol) in THF (100 mL) was added dropwise at -65 °C and stirred for an additional 60 minutes. The reaction mixture was then slowly warmed and hydrolyzed with water at 5 °C, diluted with MTB ether and acidified with hydrochloric acid solution (2N). The aqueous phase was separated and extracted with MTB ether, and the combined organic phases were washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue was extracted with n-heptane to give [2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]boronic acid as a pale yellow solid.

[0645] Step 1.4: 6-Bromo-2,4-difluoro-3-(trifluoromethyl)phenol

[0646]

[0647] A solution of 5-bromo-1,3-difluoro-2-(trifluoromethyl)benzene (CAS-no. 156243-64-0, 86 g, 321 mmol) in THF (400 mL) was cooled to -75 °C, and then a solution of lithium diisopropylamide (200 mL, 400 mmol) was added dropwise and stirred at -75 °C for 1 h. Then trimethyl borate (75 mL, 660 mmol) was added dropwise at -75 °C, and the reaction mixture was stirred for an additional 60 minutes. It was then warmed to 0 °C and a mixture of hydrochloric acid (10%, 500 mL) and THF (100 mL) was added. After phase separation, the organic phase was cooled to 0 °C. Hydrogen peroxide (210 mL, 2.68 mol) was added to the reaction mixture at 0 °C, stirred for 1 h, then heated to 40 °C and stirred overnight. It was cooled to room temperature, diluted with MTB ether, and the phases were separated. The organic phase was washed with distilled water, brine and sodium sulfite solution until peroxide-free. The organic phase was dried (sodium sulfate) and concentrated in vacuo. The residue was washed with sodium hydroxide solution and hydrochloric acid and purified by silica gel chromatography (solvent dichloromethane) to give 6-bromo-2,4-difluoro-3-(trifluoromethyl)phenol as a brown oil.

[0648] Step 1.5: 2,4-Difluoro-6-[2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]-3-(trifluoromethyl)phenol

[0649]

[0650] A mixture of 6-bromo-2,4-difluoro-3-(trifluoromethyl)phenol (9.5 g, 30 mmol), potassium carbonate (6.1 g, 44 mol), tris(dibenzylideneacetone)dipalladium(0) (57 mg, 0.1 mmol) and CataCXium A (33 mg, 0.1 mmol) in a mixture of THF (50 ml) and distilled water (25 mL) was heated to reflux under a nitrogen atmosphere, and then a solution of [2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]boronic acid 5 (7.8 g, 30 mmol) in THF (25 ml) was added dropwise. The reaction mixture was heated at reflux temperature overnight. Then it was cooled to room temperature and diluted with MTB ether and distilled water. The aqueous phase was separated and extracted with MTB ether. The combined organic phases were washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue was purified by silica gel chromatography (solvent 1-chlorobutane). 2,4-Difluoro-6-[2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]-3-(trifluoromethyl)phenol 8 was isolated as a light brown solid.

[0651] Step 1.6: 2,4-Difluoro-7-(4-n-propylcyclohex-1-en-1-yl)-3-(trifluoromethyl)dibenzofuran

[0652]

[0653] A mixture of 2,4-difluoro-6-[2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]-3-(trifluoromethyl)phenol 8 (3.2 g, 8 mmol), potassium phosphate monohydrate (2.4 g, 10 mmol) and 1,3-dimethyltetrahydro-2(1H)-pyrimidinone (30 mL, 248 mmol) was stirred overnight at 110 °C. The reaction mixture was purified by silica gel chromatography (solvent n-heptane) and crystallization (ethanol) to give 2,4-difluoro-7-(4-propylcyclohex-1-en-1-yl)-3-(trifluoromethyl)dibenzofuran as a colorless solid.

[0654] Phase sequence: Tg -35 °C K 67 °C S X (33 °C) S A (40 °C) I; Δε = 18.5; Δn = 0.2036.

[0655] Synthesis example 2: Synthesis of 2,4-difluoro-7-(4-n-propylcyclohex-1-en-1-yl)-3-(trifluoromethyl)dibenzothiophene (2)

[0656]

[0657] Step 2.1: [2,4-Difluoro-6-[2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]-3-(trifluoromethyl)phenyl]trifluoromethanesulfonate

[0658]

[0659] Under a nitrogen atmosphere at 5 °C, trifluoromethanesulfonic anhydride (3 mL, 18 mmol) was slowly added to a solution of 2,4-difluoro-6-[2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]-3-(trifluoromethyl)phenol (6 g, 14 mmol), triethylamine (3 mL, 21 mmol), and 4-(dimethylamino)pyridine (52 mg, 0.4 mmol) in dichloromethane (65 mL). The solution was stirred overnight at room temperature. The reaction mixture was purified by silica gel chromatography (solvent: 1-chlorobutane) to give [2,4-difluoro-6-[2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]-3-(trifluoromethyl)phenyl]trifluoromethanesulfonate as a yellow oil.

[0660] Step 2.2: 2,4-Difluoro-7-(4-n-propylcyclohex-1-en-1-yl)-3-(trifluoromethyl)dibenzothiophene

[0661]

[0662] A solution of [2,4-difluoro-6-[2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenyl]-3-(trifluoromethyl)phenyl]trifluoromethanesulfonate (8.2 g, 15 mmol), 2-ethylhexyl 3-mercaptopropionate (4.3 mL, 18 mmol), and N-ethyldiisopropylamine (3.7 mL, 22 mmol) in toluene (40 mL) was degassed with argon. Tris(dibenzylideneacetone)dipalladium(0) (140 mg, 0.2 mmol) and (oxydi-2,1-phenylene)bis(diphenylphosphine) (160 mg, 0.3 mmol) were quickly added to the solution, and the reaction mixture was heated to reflux overnight. It was then cooled to room temperature, and a solution of potassium tert-butoxide (2.0 g, 18 mmol) in THF (12 mL) was added in situ to the reaction mixture containing the intermediate. The reaction mixture was heated to reflux overnight, and then a second portion of a solution of potassium tert-butoxide (1.0 g, 9 mmol) in THF (6 mL) was added. The reaction mixture was heated to reflux again overnight. It was then cooled to room temperature, quenched with water, acidified with hydrochloric acid (25%) at 0 °C, and diluted with MTB ether. The aqueous phase was separated and extracted with MTB ether. The combined organic phases were washed with distilled water and brine, dried (sodium sulfate), and concentrated in vacuo. The residue was purified by silica gel chromatography (solvent: n-heptane) and crystallization (ethanol) to give 2,4-difluoro-7-(4-propylcyclohex-1-en-1-yl)-3-(trifluoromethyl)dibenzothiophene 12 as colorless crystals.

[0663] Phase sequence: K 150 °C S X116 °C I; Δε = 22.9; Δn = 0.2101.

[0664] Synthesis example 3: Synthesis of 4-fluoro-3-(4-propyl-cyclohex-1-enyl)-7-trifluoromethyl-dibenzofuran:

[0665]

[0666] Step 3.1 : 2',3'-Difluoro-4'-(4-propyl-cyclohex-1-enyl)-4-trifluoromethyl-biphenyl-2-ol

[0667]

[0668] A mixture of 2-bromo-5-trifluoromethyl-phenol (2) (CAS 402-05-1) (10 g, 41 mmol), potassium carbonate (8.4 g, 61.0 mmol), tris(dibenzylideneacetone)-dipalladium(0) (80 mg, 0.08 mmol) and CataCXium A (50 mg, 0.13 mmol) in THF (50 mL) and distilled water (33 mL) was heated to reflux under a nitrogen atmosphere, and then a solution of 2,3-difluoro-4-(4-propylcyclohex-1-enyl)-phenylboronic acid (1) (11.6 g, 41 mmol) in THF (50 mL) was added dropwise. The reaction mixture was heated overnight at the reflux temperature. Then it was cooled to room temperature and diluted with MTB-ether and distilled water. The aqueous phase was separated and extracted with MTB-ether. The combined organic phases were washed with distilled water and brine, dried (sodium sulfate) and concentrated in vacuo. The residue was purified by silica gel chromatography (solvent 1-chlorobutane). 2',3'-Difluoro-4'-(4-propyl-cyclohex-1-enyl)-4-trifluoromethyl-biphenyl-2-ol (3) was isolated as a yellow solid.

[0669] Step 3.2 : 4-fluoro-3-(4-propyl-cyclohex-1-enyl)-7-trifluoromethyl-dibenzofuran

[0670]

[0671] A mixture of 2',3'-difluoro-4'-(4-propyl-cyclohex-1-enyl)-4-trifluoromethyl-biphenyl-2-ol (3) (5.9 g, 15 mmol), potassium phosphate monohydrate (4.5 g, 18.7 mmol) and 1,3-dimethyltetrahydro-2(1H)-pyrimidinone (60 mL, 0.5 mol) was stirred overnight at 110 °C. The reaction mixture was purified by silica gel chromatography (solvent: n-heptane) and crystallization (ethanol) to give 4-fluoro-3-(4-propyl-cyclohex-1-enyl)-7-trifluoromethyl-dibenzofuran (4) as white crystals.

[0672] Compound (4) has the following phase characteristics:

[0673] K 92 °C SmA 110 °C I and properties:

[0674] Δn = 0.1994; Δε = 5.0; γ 1 = 397.

[0675] Synthesis example 4 : Synthesis of 4-fluoro-3-(4-propyl-cyclohex-1-enyl)-7-trifluoromethyl-dibenzothiophene (4)

[0676]

[0677] Synthesis example 5 : Synthesis of 4-fluoro-7-(4-propyl-cyclohex-1-enyl)-3-trifluoromethoxy-dibenzofuran (5)

[0678]

[0679] Synthesis example 6 : Synthesis of 4-fluoro-7-(4-propyl-cyclohex-1-enyl)-3-trifluoromethoxy-dibenzothiophene:

[0680]

[0681] Step 6.1 : 3,2'-Difluoro-4'-(4-propyl-cyclohex-1-enyl)-4-trifluoromethoxy-biphenyl-2-ol

[0682]

[0683] 6-Bromo-2-fluoro-3-(trifluoromethoxy)phenol (2, CAS 1805580-01-1) (15 g, 50 mmol), potassium carbonate (10.4 g, 75 mmol), tris(dibenzylideneacetone)dipalladium(0) (100 mg, 0.1 mmol), and CataCXium A (60 mg, 0.16 mmol) in a mixture of THF (100 mL) and distilled water (50 mL) were heated to reflux under a nitrogen atmosphere, and then a solution of 2-fluoro-4-(4-propylcyclohex-1-en-1-yl)phenylboronic acid (1) (13.2 g, 50 mmol) in THF (50 mL) was added dropwise. The reaction mixture was heated at reflux temperature overnight. Then it was cooled to room temperature and diluted with MTB ether and distilled water. The aqueous phase was separated and extracted with MTB-ether. The combined organic phases were washed with distilled water and brine, dried (sodium sulfate), and concentrated in vacuo. The residue was purified by silica gel chromatography (solvent: 1-chlorobutane). 3,2'-Difluoro-4'-(4-propylcyclohex-1-enyl)-4-(trifluoromethoxy)biphenyl-2-ol (3) was isolated as a brown solid.

[0684] Step 6.2 : 3,2'-Difluoro-4'-(4-propylcyclohex-1-enyl)-4-(trifluoromethoxy)biphenyl-2-yl trifluoromethanesulfonate

[0685]

[0686] Under a nitrogen atmosphere at 5 °C, trifluoromethanesulfonic anhydride (5 mL, 30 mmol) was slowly added to a solution of 3,2'-difluoro-4'-(4-propylcyclohex-1-enyl)-4-(trifluoromethoxy)biphenyl-2-ol (3) (10 g, 24 mmol), TEA (5 mL, 36 mmol), and DMAP (90 mg, 0.74 mmol) in dichloromethane (100 mL). The solution was stirred at room temperature overnight. The reaction mixture was purified by silica gel chromatography (solvent: 1-chlorobutane) to give 3,2'-difluoro-4'-(4-propylcyclohex-1-enyl)-4-(trifluoromethoxy)biphenyl-2-yl trifluoromethanesulfonate (4) as a brown oil.

[0687] Step 6.3 : 4-Fluoro-7-(4-propylcyclohex-1-enyl)-3-(trifluoromethoxy)dibenzothiophene

[0688]

[0689] The reaction is carried out as a one-pot reaction. In the first step, a solution of 3,2'-difluoro-4'-(4-propyl-cyclohex-1-enyl)-4-trifluoromethoxy-biphenyl-2-yl trifluoromethanesulfonate (4) (13.3 g, 23 mmol), 2-ethylhexyl 3-mercaptopropionate (7 mL, 30 mmol), N-ethyldiisopropylamine (6.5 mL, 38 mmol) and toluene (60 mL) was degassed with argon for 1 hour. Tris(dibenzylideneacetone)dipalladium(0) (240 mg, 0.25 mmol) and (oxydi-2,1-phenylene)bis(diphenylphosphine) (270 mg, 0.49 mmol) were rapidly added to the solution, and the reaction mixture was heated to the reflux temperature overnight. Then it was cooled to room temperature. In the second step, a solution of potassium tert-butoxide (3.5 g, 31 mmol) in THF (30 mL) was added in situ to the reaction mixture containing the intermediate (5). The reaction mixture was heated at the reflux temperature overnight, and then a second portion of a solution of potassium tert-butoxide (1.75 g, 16 mmol) in THF (15 mL) was added. Again, the reaction mixture was heated at the reflux temperature overnight. Then it was cooled to room temperature, quenched with distilled water and hydrochloric acid (25%) at 0 °C and diluted with MTB-ether. The aqueous phase was separated and extracted with MTB-ether. The combined organic phases were washed with distilled water and brine, dried (sodium sulfate) and concentrated in vacuo. The residue was purified by silica gel chromatography (solvent heptane) to give 4-fluoro-7-(4-propyl-cyclohex-1-enyl)-3-trifluoromethoxy-dibenzothiophene (6) as white crystals.

[0690] Compound (6) has the following phase characteristics:

[0691] K 101 °C SmA 194 °C I and properties:

[0692] Δn = 0.2143; Δε = 10.8; γ 1 = 556.

[0693] In the following table, the following end group abbreviations are used

[0694]

[0695] The physical properties are given at a temperature of 20 °C and the unit of γ 1 is mPa·s.

[0696]

[0697]

[0698]

[0699]

[0700]

[0701]

[0702]

[0703]

[0704]

[0705]

[0706]

[0707]

[0708]

[0709]

[0710]

[0711]

[0712]

[0713]

[0714]

[0715]

[0716]

[0717]

[0718]

[0719]

[0720]

[0721]

[0722]

[0723]

[0724]

[0725]

[0726]

[0727]

[0728]

[0729]

[0730]

[0731]

[0732]

[0733]

[0734]

[0735]

[0736]

[0737]

[0738]

[0739]

[0740]

[0741]

[0742]

[0743]

[0744]

[0745]

[0746]

[0747]

[0748]

[0749]

[0750]

[0751]

[0752]

[0753]

[0754]

[0755]

[0756]

[0757]

[0758]

[0759]

[0760]

[0761]

[0762]

[0763]

[0764]

[0765]

[0766]

[0767]

[0768]

[0769]

[0770]

[0771]

[0772]

[0773]

[0774]

[0775]

[0776]

[0777]

[0778]

[0779]

[0780]

[0781]

[0782]

[0783]

[0784]

[0785]

[0786]

[0787]

[0788]

[0789]

[0790]

[0791]

[0792]

[0793]

[0794]

[0795]

[0796]

[0797]

[0798]

[0799]

[0800]

[0801]

[0802]

[0803]

[0804]

[0805]

[0806]

[0807]

[0808]

[0809]

[0810]

[0811]

[0812]

[0813] Mixture examples The following exemplary mixtures are disclosed.

[0814] Comparative mixture A

[0815] The following mixture (CE-A) was prepared and studied.

[0816]

[0817]

[0818] Note: t.b.d.: to be determined

[0819] Table 1

[0820]

[0821] Note: All extrapolated values are at 20 °C,

[0822] *: [mPa·s / pN], and

[0823] t.b.d.: to be determined

[0824] Table 1 (continued)

[0825]

[0826] Note: All extrapolated values are at 20 °C,

[0827] *: [mPa·s / pN] and t.b.d.: to be determined

[0828] These mixtures, mixtures A-1 to A-6, have a good dielectric ratio (ε ⊥ / Δε), a good (γ 1 / k 11 ) ratio, and are characterized by very good transmittance in an FFS display and exhibit a very short response time. Also, they exhibit excellent low-temperature stability at least up to a temperature of -20 °C.

[0829] Example 1

[0830] The following mixture (M-1) was prepared and studied.

[0831]

[0832] This mixture, the mixture M-1 has a dielectric ratio (ε ⊥ / Δε) of 1.39, is characterized by very good transmittance in an FFS display and has very good low-temperature stability.

[0833] Example 2

[0834] The following mixture (M-2) was prepared and studied.

[0835]

[0836] This mixture, the mixture M-2 has a dielectric ratio (ε ⊥ / Δε) of 1.69, is characterized by very good transmittance in an FFS display and has very good low-temperature stability.

[0837] Example 3

[0838] The following mixture (M-3) was prepared and studied.

[0839]

[0840] This mixture, the mixture M-3 has very good low-temperature stability.

[0841] Example 4

[0842] The following mixture (M-4) was prepared and studied.

[0843]

[0844] This mixture, the mixture M-4 has a dielectric ratio (ε ⊥ / Δε) of 1.70, is characterized by very good transmittance in an FFS display and has very good low-temperature stability.

[0845] Example 5

[0846] Prepare and study the following mixture (M-5).

[0847]

[0848] For this mixture, the dielectric ratio (ε ⊥ / Δε) of mixture M-5 is 2.2, and the γ 1 / k 11 ratio is 4.45. It is characterized by very good transmittance, fast switching time in an FFS display, and very good low-temperature stability.

[0849] Example 6

[0850] Prepare and study the following mixture (M-6).

[0851]

[0852] For this mixture, the dielectric ratio (ε ⊥ / Δε) of mixture M-6 is 1.87, and the γ 1 / k 11 ratio is 4.55. It is characterized by very good transmittance, fast switching time in an FFS display, and very good low-temperature stability.

[0853] Example 7

[0854] Prepare and study the following mixture (M-7).

[0855]

[0856] For this mixture, the dielectric ratio (ε ⊥ / Δε) of mixture M-7 is 1.95, and the γ 1 / k 11 ratio is 4.53. It is characterized by very good transmittance, fast switching time in an FFS display, and very good low-temperature stability.

Claims

1. A liquid crystal medium having a nematic phase and a dielectric anisotropy (Δε) of 0.5 or greater, characterized in that it contains 1% by weight or more to 20% by weight or less of one or more X compounds selected from the compounds of formulae X-1 to X-6 wherein W represents O or S, R represents H, an alkyl group having 1 to 15 C atoms, where one or more CH 2 groups may each independently of one another be replaced by -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that O atoms are not directly linked to one another, and where one or more H atoms may be replaced by halogen, and A, each time it occurs, is the same or different and represents a group selected from the following group: a) The group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, and decahydronaphthalene-2,6-diyl, wherein one or more non-adjacent CH 2 groups may be replaced by -O- and / or -S-, and one or more H atoms may be replaced by F, b) the group consisting of 1,4-phenylene and 2,6-naphthylene, wherein one or two CH groups may be replaced by N, and wherein in addition, one or more H atoms may be replaced by L, c) the group consisting of 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, thiophene-2,5-diyl, selenophene-2,5-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, each of which may be mono- or polysubstituted by L, d) the group consisting of bicyclo-[1.1.1]-pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl and spiro-[3.3]-heptane-2,6-diyl, wherein one or more H atoms may be replaced by F, L are each the same or different and represent halogen, cyano, an alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl having 1 to 7 C atoms, wherein one or more H atoms may be replaced by F or Cl, Z represents, each time it appears, the same or differently, a single bond, -CF 2 O-, -OCF 2 -, -CH 2 CH 2 -, -CF 2 CF 2 -, -C(O)O-, -OC(O)-, -CH 2 O-, -OCH 2 -, -CF=CH-, -CH=CF-, -CF=CF-, -CH=CH- or -C≡C-, n represents 0, 1 or 2, Y 1 , Y 2 and Y 3 each independently represents H, F, Cl, CF 3 or CHF 2 , provided that one of Y 1 and Y 2 is not H or Y 3 is F, and if both Y 1 and Y 3 are F, then Y 2 is not H, and X represents F, Cl, CN, NCS, SF 5 , fluoroalkyl, fluoroalkoxy, fluoroalkenyl or fluoroalkenyloxy each having at most 5 carbon atoms; one or more compounds selected from the compounds of formulae II and III: wherein R 2 represents an alkyl, alkoxy, fluoroalkyl or fluoroalkoxy group having 1 to 7 C atoms, an alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl group having 2 to 7 C atoms, each, each time it occurs, independently of one another represents L 21 and L 22 represents H or F, X 2 represents a halogen, a haloalkyl or haloalkoxy group having 1 to 3 C atoms, or a haloalkenyl or haloalkenyloxy group having 2 or 3 C atoms m represents 0, 1, 2 or 3, R 3 represents an alkyl, alkoxy, fluoroalkyl or fluoroalkoxy group having 1 - 7 C atoms, an alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl group having 2 - 7 C atoms, each, each time it occurs, independently of one another is L 31 and L 32 each independently represents H or F, X 3 represents a halogen, a haloalkyl or haloalkoxy group having 1 to 3 C atoms, or a haloalkenyl or haloalkenyloxy group having 2 or 3 C atoms, F, Cl, -OCF 3 , -OCHF 2 , -O-CH 2 CF 3 , -O-CH=CF 2 , -O-CH=CH 2 or -CF 3 , Z 3 represents -CH 2 CH 2 -, -CF 2 CF 2 -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH 2 O- or a single bond, and n represents 0, 1, 2 or 3; and one or more dielectrically neutral compounds selected from formulae IV and V: wherein R 41 and R 42 each independently has the meaning as defined for R in Formula II 2 described above each independently of one another and if Appears twice then these also independently of one another represent, Z 41 and Z 42 are each independently and if Z 41 occurs twice, these also each independently represent -CH 2 CH 2 -, -COO-, trans-CH=CH-, trans-CF=CF-, -CH 2 O-, -CF 2 O-, -C≡C- or a single bond, p represents 0, 1 or 2, R 51 and R 52 each independently has one of the meanings shown for R 41 and R 42 one of the meanings shown to if present, each independently of one another represents Z 51 from Z to 53 each independently represents -CH 2 -CH 2 -, -CH 2 -O-, -CH=CH-, -C≡C-, -COO- or a single bond, and i and j each independently of one another represent 0 or 1.

2. The medium according to claim 1, characterized in that one or more X compounds are selected from the following: wherein, n is an integer from 1 to 9.

3. The medium according to claim 1 or 2, characterized in that it contains one or more compounds of formula B wherein indicate indicate n represents 1 or 2, R 1 represents alkyl, alkoxy, fluoroalkyl, fluoroalkoxy, alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl, and X 1 represents F, Cl, fluoroalkyl, fluoroalkenyl, fluoroalkoxy or fluoroalkenyloxy.

4. The medium according to claim 1 or 2, characterized in that it further contains one or more compounds of formula I: wherein indicate indicate n represents 0 or 1, R 11 and R 12 each independently represents an alkyl group, an alkoxy group, a fluoroalkyl group or a fluoroalkoxy group, an alkenyl group, an alkenyloxy group, an alkoxyalkyl group or a fluoroalkenyl group having 2 to 7 C atoms, and R 11 optionally represents R 1 and R 12 optionally represents X 1 , R 1 represents an alkyl, alkoxy, fluoroalkyl or fluoroalkoxy group having 1 to 7 C atoms, an alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl group having 2 to 7 C atoms, and X 1 represents F, Cl, fluoroalkyl, fluoroalkenyl, fluoroalkoxy or fluoroalkenyloxy, wherein the compound of formula B is not contained therein.

5. The liquid crystal medium according to claim 1, characterized in that it contains one or more compounds selected from formulae VI-IX: wherein R 61 represents an unsubstituted alkyl group having 1 - 7 C atoms, an unsubstituted alkenyl group having 2 - 7 C atoms, an unsubstituted alkoxy group having 1 - 6 C atoms or an unsubstituted alkenyloxy group having 2 - 6 C atoms, R 62 represents an unsubstituted alkyl group having 1 - 7 C atoms, an unsubstituted alkoxy group having 1 - 6 C atoms, or an unsubstituted alkenyloxy group having 2 - 6 C atoms, and l represents 0 or 1, R 71 represents an unsubstituted alkyl group having 1 - 7 C atoms, or an unsubstituted alkenyl group having 2 - 7 C atoms, R 72 represents an unsubstituted alkyl group having 1 - 7 C atoms, an unsubstituted alkoxy group having 1 - 6 C atoms, or an unsubstituted alkenyloxy group having 2 - 6 C atoms indicate R 81 represents an unsubstituted alkyl group having 1 - 7 C atoms, or an unsubstituted alkenyl group having 2 - 7 C atoms, R 82 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, indicate Z 8 represents -(C=O)-O-, -CH 2 -O-, -CF 2 -O- or -CH 2 -CH 2 -, o represents 0 or 1, R 91 and R 92 each independently has the meaning given above for R 72 as set forth indicate p and q independently of one another represent 0 or 1.

6. The medium according to claim 3, characterized in that the total concentration of the compound of formula B in the entire medium is 1% or greater to 60% or less.

7. The medium according to claim 1 or 2, characterized in that it further contains one or more chiral compounds and / or stabilizers.

8. An electro-optical display or electro-optical component, characterized in that it contains the liquid crystal medium according to any one of claims 1-7.

9. The display according to claim 8, characterized in that it is based on the IPS mode or the FFS mode.

10. The display according to claim 8 or 9, characterized in that it comprises an active matrix addressing device.

11. Use of a medium according to any one of claims 1 - 7 in an electro - optical display or an electro - optical component.

12. A method for preparing a liquid crystal medium according to any one of claims 1 - 7, characterized in that one or more compounds of formula X are mixed with one or more further mesogenic compounds and optionally one or more additives.

Images