JP2007284439A - Liquid crystal compound, liquid crystal medium and method for preparing the liquid crystal medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new compound suitable as a liquid crystal. <P>SOLUTION: The compounds are expressed by formula (I) [wherein, formula (II) is shown by formula (III); regarding to Z<SP>1</SP>, Z<SP>2</SP>, L<SP>1</SP>to L<SP>4</SP>, X, (u) and (v), L<SP>1</SP>to L<SP>4</SP>are each independently H or F; Z<SP>1</SP>, Z<SP>2</SP>are each independently -CO-O-, -O-CO-, -C<SB>2</SB>F<SB>4</SB>-, C<SB>2</SB>H<SB>4</SB>-, -CH=CH-, -CF=CF-, CH=CF-, -CF=CH-, -CH<SB>2</SB>O-, OCH<SB>2</SB>-, -C≡C- or a single bond; X is F, Cl, CN, OCN, NCS, SCN, SF<SB>5</SB>, a ≤6C unsubstituted alkyl, alkoxy, alkyl halide, alkenyl halide, halogenated alkoxy or halogenated alkenyloxy; (u) is 0, 1, 2 or 3: and (v) is 1 or 2 and provided that (u+v) is ≤3] and a liquid crystal display equipped with ≥1 kind of the compound is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a novel compound, the use of the compound for electro-optical purposes or in a liquid crystal medium, and a display comprising this medium.

  Liquid crystals are mainly used as a dielectric in a display device because the optical properties of a substance can be changed by an applied voltage. Electro-optical devices based on liquid crystals are very well known to those skilled in the art and can be based on various effects. Examples of such devices include cells with dynamic scattering, DAP (deformation of aligned phases) cells, guest / host cells, TN cells with twisted nematic structures, STN (super twisted nematic) cells, SBE. (Super birefringence effect) cell and OMI (Optical mode interference) cell. The most common display device has a twisted nematic structure based on the Schadt-Helfrich effect.

  Liquid crystal materials must have good chemical and thermal stability, as well as excellent stability against electric fields and electromagnetic radiation. In addition, the liquid crystal material must have low viscosity, be used in the cell, have a short address time, a low threshold voltage and a high contrast.

  Furthermore, the liquid crystal material must have a suitable mesophase, for example the nematic or cholesteric mesophase for the cell described above, at normal operating temperatures, i.e. in the widest possible range above or below room temperature. Don't be. Since liquid crystals are usually used as a mixture of multiple components, it is important that the components are easily miscible with each other. Furthermore, characteristics such as conductivity, dielectric anisotropy and optical anisotropy must satisfy various requirements depending on the cell type and application field. For example, twisted nematic cell materials must have positive dielectric anisotropy and low electrical conductivity.

  For example, for matrix liquid crystal displays (MLC displays) with integrated nonlinear elements for individual pixel switching, large positive dielectric anisotropy, wide nematic phase, relatively low birefringence, very high resistivity A medium with excellent UV and temperature stability and low vapor pressure is desired.

  This type of matrix type liquid crystal display is known. Non-linear elements that can be used for the respective switching of the individual pixels are, for example, active elements (ie transistors). The term “active matrix” is divided into two distinct types.

  1. MOS (metal oxide semiconductor) or other diode on a silicon wafer as substrate.

  2. A thin film transistor (TFT) on a glass plate as a substrate.

  When single crystal silicon is used as the substrate material, even in the case of a module assembly of various component displays, a problem occurs in the connection portion, so that the size of the display is limited.

  In the preferred and more promising second type, the electro-optic effect used is usually the TN effect. In this case, there are two techniques that can be distinguished. That is, for example, a TFT including a compound semiconductor, such as CdSe, and a TFT based on polycrystalline or amorphous silicon.

  The TFT matrix is formed on the inner surface of one glass plate of the display, and the other glass plate has a transparent counter electrode on the inner surface. Compared to the size of the pixel electrode, the TFT is very small and has virtually no adverse effect on the image. This technology can also be applied to full color displays. In this display, a mosaic of red, green and blue filters is arranged so that the filter element faces each of the switchable pixels.

  A TFT display is usually illuminated by a backlight, operating a TN cell with a polarizing plate orthogonal to the transmitted light.

  The term “MLC display” here also includes all matrix displays with integrated nonlinear elements. That is, in addition to the active matrix, it also includes displays with passive elements such as varistors or diodes (MIMs, ie, metal-insulator-metal).

  This type of MLC display is particularly suitable for television applications (eg pocket television) or for advanced information display applications used for computers (laptops) and in cars or aircraft. In addition to the problem of contrast angle dependency and response time, the MLC display has a problem caused by the fact that the specific resistance of the liquid crystal mixture is not sufficiently high (see Non-Patent Documents 1 and 2). As the resistance decreases, the contrast of the MLC display deteriorates and a problem of afterimage erasure may occur. The specific resistance of the liquid crystal mixture is generally involved throughout the life of the MLC display due to its interaction with the internal surface of the display, so a high (initial) resistance is required to obtain an acceptable service life. It is very important to have In particular, in the case of a low-voltage mixture, it has heretofore been impossible to achieve a high resistance value. It is also important that the resistivity decrease is as small as possible after the temperature rise and heating and / or UV irradiation. Also, the low temperature characteristics of the matrix in the prior art are a problem. It is required that no crystal and / or smectic phase is generated even at a low temperature, and that the temperature dependence of viscosity is also as low as possible. Thus, prior art MLC displays do not meet today's requirements.

  Therefore, an MLC display having a very high specific resistance as well as a wide operating temperature range, a short response time even at a low temperature, and a low threshold voltage. However, there is a strong demand for those that have been reduced.

In a TN (Schadt-Helfrich) cell, a medium that promotes the following advantages in the cell is desired:
・ Wide range of nematic phase (especially to low temperatures)
・ Switching capability at extremely low temperatures (outdoor applications, automobiles, aircraft)
-Higher resistance to UV irradiation (longer lifetime).

  With media available from the prior art, these advantages cannot be achieved while maintaining other properties at the same time.

  In the case of a super twist type (STN) cell, a medium that allows greater time-division driving and / or a lower threshold voltage and / or a wider nematic phase range (especially at low temperatures) is desired. For this purpose, it is urgently desired to further expand the feasible range of characteristic values (clearing point, smectic-nematic phase transition or melting point, viscosity, dielectric characteristic value, elastic characteristic value).

Thus, the present invention does not exhibit or reduce the above disadvantages, especially in MLC, TN or STN applications, and preferably has a high clearing point and a low rotational viscosity (γ ₁ ) at the same time. It is an object to provide a novel compound having the above. In particular, compounds of formula I can be used to prepare low _Vth mixtures with very good γ ₁ / clearing point ratios and relatively low values of Δn. In particular, the compounds and mixtures of the present invention are suitable for applications where Δn is low. Preferably, the mixtures according to the invention are used in reflective and transflective applications.

In order to improve the stability / drive voltage window of a low threshold voltage (V _th ) TFT liquid crystal mixture, it is desirable to minimize or remove the ester component because the ester component is less stable. However, removal of the esteric material increases both the stability of the mixture and the _Vth . Therefore, there is a need to find an improved material that has the polar characteristics of esters and also has stability, such as a material in which the rings are linked by a single bond without an ester bond. Replacing the esteric carbonyl functionality with a difluoromethyl group is one way in which both the voltage and stability of the liquid crystal mixture can be improved.

  There are a large number of prior arts on liquid crystal materials with difluoromethyleneoxy bonds, but there are few documents related to the report in the present invention. This is summarized below.

Patent Document 1 discloses a general formula characterized by a compound having a CF ₂ O— group, but the material of the present invention is not clearly described.

Patent Document 2 covers the use of a CF ₂ O material in combination with an alkenyl material in a liquid crystal mixture.

Patent Document 3 is a patent application for a method for producing a CF ₂ O liquid crystal, but does not include a specific compound as in the present application.

Patent Document 4 relates to a mixture that theoretically contains a CF ₂ O compound of the general formula, and is used in combination with a chiral dopant. This general formula covers many liquid crystals, but the compounds of the present invention are not disclosed.
German Patent No. 4006921 International Publication No. 01 / 46336A2 Pamphlet German Patent Application Publication No. 1944228A1 European Patent No. 609566B1 TOGASHHI, S.M. SEKIGUCHI, K .; TANABE, H .; , YAMAMOTO, E .; SORIMACHI, K .; TAJIMA, E .; WATANABE, H .; And SHIMIZU, H .; "Matrix LCD Controlled by Double Stage Diode Rings", Proc. Eurodisplay, (Paris), September 1984, Vol. 84, No. A210-288, p. 141ff STROMER, M.M. "Design of Thin Film Transistors for Matrix Addressing of Television Liquid Crystal Displays," Proc. Eurodisplay, (Paris), September 1984, Vol. 84, p. 145ff

One object of the present invention is to find new compounds suitable for liquid crystal mixtures. To replace other known compounds having an ester compound or CF 2 _O-group, the novel compounds, when used alone or in the liquid crystal mixture, equal to or more parameters, good stability and high reliability Must have sex.

  It has been found that this object is achieved by using the compounds according to the invention in liquid-crystalline media.

  The present invention therefore relates to compounds characterized by the general formula I.

式中、

Where

Ｌ^１〜４は、それぞれ互いに独立に、ＨまたはＦであり、
Ｚ^１およびＺ^２は、それぞれ互いに独立に、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−Ｃ_２Ｆ_４−、−Ｃ_２Ｈ_４−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−、−ＣＨ＝ＣＦ−、−ＣＦ＝ＣＨ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−Ｃ≡Ｃ−または単結合であり、
Ｘは、Ｆ、Ｃｌ、ＣＮ、ＯＣＮ、ＮＣＳ、ＳＣＮ、ＳＦ_５、６個以下の炭素原子を有する無置換のアルキルまたはアルコキシ基、ハロゲン化アルキル基、ハロゲン化アルケニル基、ハロゲン化アルコキシ基またはハロゲン化アルケニルオキシ基であり、
ｕは、０、１、２または３であり、および
ｖは、１または２であり、ただしｕ＋ｖは３以下である。

L ^1-4 are each independently H or F,
Z ¹ and Z ² are each independently of each other —CO—O—, —O—CO—, —C ₂ F ₄ —, —C ₂ H ₄ —, —CH═CH—, —CF═CF—, -CH = CF -, - CF = CH -, - CH 2 O -, - OCH 2 -, - C≡C- or a single bond,
X is F, Cl, CN, OCN, NCS, SCN, SF ₅ , an unsubstituted alkyl or alkoxy group having 6 or less carbon atoms, a halogenated alkyl group, a halogenated alkenyl group, a halogenated alkoxy group or a halogen An alkenyloxy group,
u is 0, 1, 2 or 3, and v is 1 or 2, provided that u + v is 3 or less.

  The compounds of formula I are applicable in a wide range. Depending on the choice of substituents, these compounds serve as the basic material that mainly constitutes the liquid crystal medium. However, for example to modify the dielectric anisotropy and / or optical anisotropy of the dielectric and / or to optimize the threshold voltage and / or viscosity of the dielectric for liquid crystal base materials with other types of compounds In addition, compounds of the formula I can also be added.

  The compounds of formula I are colorless and form liquid crystal media in the preferred temperature range for electro-optical use. These compounds are chemically, thermally and light stable. Since these compounds have no further substituent at the terminal portion, they can be produced particularly easily as compared with the prior art. The compounds of the present invention are particularly useful for liquid crystal media that simultaneously have low rotational viscosity and high dielectric anisotropy.

Particularly preferred compounds of the formula I are selected from the group consisting of the following subordinate formulas I1 to I5, wherein L ^{1 to 8} are H or F.

式Ｉ１〜Ｉ５の中でも、式Ｉ１の化合物が好ましい。

Of the formulas I1 to I5, compounds of the formula I1 are preferred.

Of the formulas I and its dependent formulas, preferably at least one of L ¹ and L ² is F. Most preferably, both L ¹ and L ² are F.

  Compounds of formula I are synthesized by methods known per se in the literature (for example, as standard, see Houben-Weyl, Method der Organicis Chemie [Methods of Organic Chemistry], George-Thiet-Vert, )etc). Precisely, it is synthesized under known reaction conditions suitable for the synthesis of these compounds. Also, although not described in great detail here, it is also possible to use variants of methods known per se.

  Compounds of formula I are preferably prepared as follows (Schemes 1 and 2).

スキーム１：環Ｂが芳香環（ｖが１）の場合の式Ｉの化合物の調製

Scheme 1: Preparation of compounds of formula I when ring B is an aromatic ring (v is 1)

スキーム２：環ＡおよびＢがシクロヘキサンの場合の式Ｉの化合物の調製

Scheme 2: Preparation of compounds of formula I when rings A and B are cyclohexane

The reaction sequence of Scheme 1 is self-evident. Other starting materials can be used to obtain compounds similar to Formula 8. For example, other p-bromobenzoic acid derivatives can be used according to the starting material of formula 2. Similarly, the second ring from the right of formula 8 can be changed according to ring C in formula I. In order to achieve the variation of the product of formula 8, starting materials of formula 5 can also have various substituents L ¹ ~L ^4.

  The synthesis described in Scheme 2 is also self-evident. The transformations in Schemes 1 and 2 are known in the art. The compound of formula 9 can also be converted to a bis (alkylthio) carbenium salt by several known methods. By changing the bicyclohexyl group in structure 9, all changes of the compounds of the invention are possible.

  General formula:

（但し、環Ａ〜Ｃ、Ｚ^１およびＺ^２は式Ｉで定義される通りである）
の中の様な各種の置換基を備える他のカルボン酸類は公知であるか、一般に公知の方法で調製できる。

(Wherein rings A to C, Z ¹ and Z ² are as defined in formula I)
Other carboxylic acids with various substituents such as are known or can be prepared by generally known methods.

  Other methods for the compounds of the present invention are illustrated in Schemes 3 and 4 below and include reactions known in the prior art.

スキーム３．ジフルオロオキシメチレン−結合液晶１０の合成
ａ）ＤＡＳＴ、ＣＨ_２Ｃｌ_２；還流。 ｂ）Ｂｒ_２、ＣＣｌ_４；ｈν、１４ｄ。
ｃ）３，４，５−トリフルオロフェノール、ＮａＨ、ＤＭＦ；５０〜６０℃、
１５時間。 ｄ）１．ブロモシクロヘキサン、Ｌｉ、ＺｎＢｒ_２、ＴＨＦ、
トルエン；超音波処理、室温、４時間；２．先の臭化物、触媒［Ｐｄ（ｄｐｐｆ）
Ｃｌ_２］、ＴＨＦ、トルエン；室温。

Scheme 3. Synthesis of difluorooxymethylene-bonded liquid crystal 10 a) DAST, CH ₂ Cl ₂ ; reflux. _{b) Br 2, CCl 4;} hν, 14d.
c) 3,4,5-trifluorophenol, NaH, DMF; 50-60 ° C.
15 hours. d) Bromocyclohexane, Li, ZnBr ₂ , THF,
1. Toluene; sonication, room temperature, 4 hours; Previous bromide, catalyst [Pd (dppf)
Cl ₂ ], THF, toluene; room temperature.

スキーム４．シクロヘキシル−ａ，ａ−ジフルオロメチルフェニル
エステル類１１の他の合成ルート
収率はフェノール成分に強く依存して変化する。
ルートＡ：ａ）ＣＦ_２Ｂｒ_２、Ｐ（ＮＭｅ_２）_３、ＴＨＦ／ジオキサン １０／１；
０℃〜室温（ＲＴ）、１８時間（８０〜９０％）；ｂ）Ｂｒ_２、Ｅｔ_２Ｏ；０℃、
１時間（８５〜９５％）；ｃ）２．６等量のＸＰｈＯＮａ、ＤＭＦ；６０℃、
１８時間（３５〜７０％）；ｄ）１．Ｈ_２、５％Ｐｄ−Ｃ、ＴＨＦ；６０℃、
６０ｂａｒ；２．分取用ＨＰＬＣ；３．ｎ−ペンタンからの結晶化（２５〜
３５％）。
ルートＢ：ｅ）２，４−ビス（４−メトキシフェニル）−１，３−ジチア−２，４
−ジフォスフェタン−２，４−ジスルフィド（Ｌａｗｅｓｓｏｎ試薬）、クロロ
ベンゼン；還流、１８時間（５〜３０％）；ｆ）ＤＢＨ（１，３−ジブロモ−５，
５−ジメチルヒダントイン）、７０％ＨＦ−ピリジン、ＣＨ_２Ｃｌ_２；−７０℃〜
ＲＴ（５〜４０％）。

Scheme 4. Other synthetic routes for cyclohexyl-a, a-difluoromethylphenyl esters 11 Yields vary strongly depending on the phenolic component.
Route A: a) CF ₂ Br ₂ , P (NMe ₂ ) ₃ , THF / dioxane 10/1;
0 ° C. to room temperature (RT), 18 hours (80-90%); b) Br ₂ , Et ₂ O;
1 hour (85-95%); c) 2.6 equivalents of XPhONa, DMF; 60 ° C.
18 hours (35-70%); d) H ₂ , 5% Pd—C, THF; 60 ° C.
60 bar; 2. 2. preparative HPLC; Crystallization from n-pentane (25-
35%).
Route B: e) 2,4-bis (4-methoxyphenyl) -1,3-dithia-2,4
-Diphosphetan-2,4-disulfide (Lawesson's reagent), chlorobenzene; reflux, 18 hours (5-30%); f) DBH (1,3-dibromo-5,5)
5-dimethylhydantoin), 70% HF-pyridine, CH ₂ Cl ₂ ;
RT (5-40%).

  The present invention also relates to a liquid crystal medium, which is an electro-optic display (especially two flat parallel skins that form a cell with a frame, and a non-linear element for switching each pixel on the skin. And an STN or MLC display having a positive dielectric anisotropy and a high resistivity nematic liquid crystal mixture present in the cell, and further comprising a medium of this type, the medium being used for electro-optic purposes Related to using for. Further, in addition to the use of a reflective display, the mixture of the present invention is also suitable for an IPS (In Plane Switching) application, an OCB (Optically Controlled Birefringence) application, and a VA (Vertical Alignment) application.

  The medium according to the invention is preferably based on a plurality of (preferably two or more) compounds of the formula I, ie the proportion of these compounds is 0.5-95%, preferably 1-60%, Especially preferably, it is 1 to 40% of range.

  A preferred embodiment is shown below.

  The medium comprises one or more compounds of the formulas I1-a to I4-d.

· X is _{preferably, F, Cl, CN, OCN} , NCS, SCN, SF 5, OCH 3, CH 3, OC 2 H 5, C 2 H 5, OC 3 H 7, C 3 H 7, CF 3 , C ₂ F ₅ , C ₃ F ₇ , CF ₂ H, OCF ₃ , OCF ₂ H, OCHFHCF ₃ , OCHFHCH ₂ F, OCHFHCHF ₂ , OCF ₂ CH ₃ , OCF ₂ CH ₂ F, OCF ₂ CHF ₂ , OCF ₂ CF ₂ CF ₂ H, OCF ₂ CF ₂ CH ₂ F, OCHFHCF ₂ CF ₃ , OCHFHCF ₂ CHF ₂ , OCCFHCFHCF ₃ , OCH ₂ CF ₂ CF ₃ , OCF ₂ CF ₂ CF ₃ , OCF ₂ CFHCHF ₂ , OCF ₂ CH _{2 CHF 2, OCFHCF 2 CHF 2,} OCFHCFHCHF 2, OCFHCH 2 CF 3, OCH 2 CFHCF _{, OCH 2 CF 2 CHF 2,} OCF 2 CFHCH 3, OCF 2 CH 2 CHF 2, OCFHCF 2 CH 3, OCFHCFHCHF 2, OCFHCH 2 CF 3, OCH 2 CF 2 CHF 2, OCH 2 CFHCHF 2, OCF 2 CH 2 CH _{3, OCFHCFHCH 3, OCFHCH 2 CHF} 2, OCH 2 CF 2 CH 3, OCH 2 CFHCHF 2, OCH 2 CH 2 CHF 2, OCHFCH 2 CH 3, OCH 2 CFHCH 3, OCH 2 CH 2 CHF 2, OCClFCF 3, OCClFCClF _{2, OCClFCHF 2, OCFHCCl 2 F} , OCClFCHF 2, OCClFCClF 2, OCF 2 CHCl 2, OCF 2 CHCl 2, OCF 2 CCl 2 F, OCF 2 CClFH, _{OCF 2 CClF 2, OCF 2 CF} 2 CClF 2, OCF 2 CF 2 CCl 2 F, OCClFCF 2 CF 3, OCClFCF 2 CHF 2, OCClFCF 2 CClF 2, OCClFCFHCF 3, OCClFCClFCF 3, OCCl 2 CF 2 CF 3, OCClHCF 2 _{CF 3, OCClFCF 2 CF 3,} OCClFCClFCF 3, OCF 2 CClFCHF 2, OCF 2 CF 2 CCl 2 F, OCF 2 CCl 2 CHF 2, OCF 2 CH 2 CClF 2, OCClFCF 2 CFH 2, OCFHCF 2 CCl 2 F, OCClFCFHCHF _{2, OCClFCClFCF 2 H, OCFHCFHCClF 2} , OCClFCH 2 CF 3, OCFHCCl 2 CF 3, OCCl 2 CFHCF _{, OCH 2 CClFCF 3, OCCl 2} CF 2 CF 2 H, OCH 2 CF 2 CClF 2, OCF 2 CClFCH 3, OCF 2 CFHCCl 2 H, OCF 2 CCl 2 CFH 2, OCF 2 CH 2 CCl 2 F, OCClFCF 2 CH _{3, OCFHCF 2 CCl 2 H,} OCClFCClFCHF 2, OCFHCFHCCl 2 F, OCClFCH 2 CF 3, OCFHCCl 2 CF 3, OCCl 2 CF 2 CFH 2, OCH 2 CF 2 CCl 2 F, OCCl 2 CFHCF 2 H, OCClHCClFCF 2 H, OCF ₂ CClHCClH ₂ , OCF ₂ CH ₂ CCl ₂ H, OCClFCFHCH ₃ , OCF ₂ CClFCCl ₂ H, OCClFCH ₂ CFH ₂ , OCFHCCl ₂ CFH ₂ , OC Cl ₂ CF ₂ CH ₃ , OCH ₂ CF ₂ CClH ₂ , OCCl ₂ CFHCFH ₂ , OCH ₂ CClFCFCl ₂ , OCH ₂ CH ₂ CF ₂ H, OCClHCClHCF ₂ H, OCH ₂ CCl ₂ CF ₂ H, OCClFCH ₂ CH ₃ , OCHFCH _{2 CCl 2 H, OCClHCFHCClH 2,} OCH 2 CFHCCl 2 H, OCCl 2 CH 2 CF 2 H, OCH 2 CCl 2 CF 2 H, CH = CF 2, OCH = CF 2, CF = CF 2, OCF = CF 2, CF = CHF, OCF = CHF, CH = CHF, OCH = CHF, CF 2 CH 2 CF 3 or _CF 2 CHFCF _3, in _{particular, F, Cl, CN, CF} 3, CHF 2, OCF 3, OCHF 2, OCFHCF 3 , OCFHCHF _2, OCFHCH _{F, OCF 2 CH 3, OCF} 2 CHF 2, OCF 2 CH 2 F, OCF 2 CF 2 CHF 2, OCF 2 CF 2 CH 2 F, OCFHCF 2 CF 3, OCFHCF 2 CHF 2, OCF 2 CF 2 CF 3, a _{OCF 2 CF 2 CClF 2, OCClFCF} 2 CF 3, CH = CF 2, OCH 3, OC 2 H 5 or _OC 3 _{H 7.}

  The proportion of the compound of formula I in the whole liquid crystal medium is 1 to 40% by weight, preferably 1 to 30% by weight, particularly preferably 1 to 25% by weight.

  In the above applications, the liquid crystal medium preferably comprises at least one compound of formula I and the nematic host mixture comprises one or more nematic or nematic compounds.

  Preferably, the liquid crystal medium comprises 2 to 25, preferably 3 to 15 compounds, at least one of which is a compound of formula I. The other compound constitutes a nematic host mixture, preferably a low molecular weight liquid crystal compound selected from nematic or nematic materials, such as azoxybenzenes, benzylidene-anilines, biphenyls, terphenyls, phenyl or Cyclohexylbenzoic acid esters, phenyl or cyclohexyl esters of cyclohexanecarboxylic acid, phenyl or cyclohexyl esters of cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexylcyclohexanecarboxylic acid, benzoic acid, cyclohexanecarboxylic acid or cyclohexyl of cyclohexanecarboxylic acid Phenyl esters, phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexyl Hexanes, cyclohexylcyclohexanes, cyclohexylcyclohexenes, cyclohexylcyclohexylcyclohexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis-cyclohexylbiphenyls, phenyl- or cyclohexylpyrimidines, phenyl- or cyclohexylpyridines , Phenyl- or cyclohexylpyridazines, phenyl- or cyclohexyldioxanes, phenyl- or cyclohexyl-1,3-dithianes, 1,2-diphenylethanes, 1,2-dicyclohexylethanes, 1-phenyl-2-cyclohexyl Ethanes, 1-cyclohexyl-2- (4-phenylcyclohexyl) ethanes, 1-cyclohexyl-2-biphenylethanes, 1-phenyl-2-silane B hexylphenyl ethanes, optionally halogenated stilbenes, benzyl phenyl ethers, the type of trunk and substituted cinnamic acids and further nematic or Ne Mato transgenic material. In addition, the 1,4-phenylene group in these compounds may be mono- or difluorine-substituted on the side chain.

  The most important compounds possible as components of these liquid crystal mixtures can be characterized by the following formula:

R'-L'-G'-ER "
However, L 'and E may be the same or different, and are independently of each other -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr-, A divalent group from the group consisting of -Dio-, -B-Phe- and -B-Cyc- and their enantiomers, wherein Phe is an unsubstituted or fluorine-substituted 1,4-phenylene, Cyc Is trans-1,4-cyclohexylene or 1,4-cyclohexenylene, Pyr is pyrimidine-2,5-diyl or pyridine-2,5-diyl, B is 2- (trans-1,4-cyclohexyl) ethyl , Pyrimidine-2,5-diyl, Dio is 1,3-dioxane-2,5-diyl.

G ′ in these compounds is selected from the following divalent groups: —CH═CH—, —N (O) N—, —CH═CY—, —CH═N (O) —, —C≡. C—, —CH ₂ —CH ₂ —, —CO—O—, —CH ₂ —O—, —CO—S—, —CH ₂ —S—, —CF ₂ O—, —OCF ₂ —, —CH = N-, -COO-Phe-COO- or a single bond, Y is halogen, preferably chlorine or -CN.

R ′ and R ″ are each independently alkyl, alkenyl, alkoxy, alkenyloxy, alkanoyloxy, alkoxycarbonyl or alkoxycarbonyloxy of 1 to 18, preferably 3 to 12 carbon atoms, or One of R ′ and R ″ is F, SF ₅ , CF ₃ , OCF ₃ , Cl, NCS or CN.

  In most cases of these compounds, R ′ and R ″ are independently of one another alkyl, alkenyl or alkoxy of different chain lengths, the total number of carbon atoms in the nematic medium is generally between 2 and 9, Preferably between 2 and 7.

  Many of these compounds and mixtures thereof are commercially available. All of these compounds are known or are synthesized by methods known per se in the literature (for example, as standard, by Houben-Weyl, Method der Organicischemie [Methods of Organic Chemistry], Georg-Thieme- Verlag, (Stuttgart, etc.)). Precisely, it is synthesized under known reaction conditions suitable for the synthesis of these compounds. Also, although not described in great detail here, it is also possible to use variants of methods known per se.

  The MLC display of the present invention consists of a polarizer and an electrode base plate, and is a surface-treated electrode corresponding to the conventional configuration of this type of display. Here, the term “conventional configuration” is widely used and covers all changes and modifications of the MLC display, including in particular matrix display elements based on polycrystalline silicon TFTs or MIMs.

  However, an important difference between the display of the present invention and conventional displays based on twisted nematic cells is in the selection of the liquid crystal parameters of the liquid crystal layer.

  The liquid crystal mixtures which can be used in the invention are prepared by conventional methods known per se. In general, the desired amount of the compound used in the smaller amount is dissolved in the major components, preferably with warming. It is also possible to mix the component solutions in an organic solvent such as acetone, chloroform or methanol, mix thoroughly, and then remove the solvent again, for example by distillation.

  Thus, a further aspect of the present invention is a method for preparing a liquid crystal medium, wherein at least one compound of formula I is mixed with another liquid crystal compound, and further mixed with additives as necessary.

  The dielectric may also contain further additives known to those skilled in the art and described in the literature. For example, 0-15% of pleochroic dyes, stabilizers, nanoparticles or chiral dopants can be added.

The following examples illustrate the invention without limiting it. Above and below, percentages are weight percent. All temperatures are given in degrees Celsius. m. p. Represents the melting point, cl. p. Represents a clearing point. Further, C represents a crystalline state, N represents a nematic phase, S represents a smectic phase, and I represents an isotropic phase. The data between these symbols represents the phase transition temperature. Δn represents optical anisotropy (589 nm, 20 ° C.). The flow viscosity ν ₂₀ (mm ² / sec) and the rotational viscosity γ ₁ (mPa · s) were each determined at 20 ° C. Δε represents dielectric anisotropy (Δε = ε _‖ −ε _⊥ , where ε _‖ represents a dielectric constant parallel to the long-chain molecular axis, and ε _{表 す} represents a dielectric constant perpendicular thereto). Electro-optical data were measured in a TN cell at 20 ° C. with a first transmission minimum (ie, d · Δn value of 0.5 μm) unless otherwise stated. Optical data were measured at 20 ° C. unless otherwise stated.

  The Δε and Δn values of the compounds should be extrapolated linearly from the liquid crystal mixture of 10% by weight of the compound and 90% by weight of the commercially available liquid crystal mixture ZLI-4792 (Merck KGaA, Darmstadt). Measure with

  In the examples, “conventional operation” means that water is added as necessary, the mixture is extracted with dichloromethane and diethyl ether, methyl tert-butyl ether or toluene, the phases are separated, and the organic layer is dried and evaporated. Means to purify the product by vacuum distillation or crystallization and / or chromatography. The following abbreviations are used.

n-BuLi 1.6-mol n-hexane solution of n-butyllithium THF tetrahydrofuran DAST diethylaminosulfur trifluoride RT room temperature <Example 1>

Ｐ．Ｋｉｒｓｃｈら、Ａｎｇｅｗ．Ｃｈｅｍ．Ｉｎｔ．Ｅｄ．２００１年刊、第４０巻、第８号、第１４８０〜１４８４頁（スキーム１も参照）に記載される方法と類似して、ｐ−ブロモ化合物１を調製する。

P. Kirsch et al., Angew. Chem. Int. Ed. Similar to the method described in 2001, Vol. 40, No. 8, pages 1480-1484 (see also Scheme 1), p-bromo compound 1 is prepared.

  A general method for coupling boronic acids with bromobenzenes is as follows.

メタホウ酸ナトリウム８水和物（１２．５ｇ、４５．０ｍｍｏｌ）の水溶液（７２ｍｌ）に、塩化ビス（トリフェニルホスフィン）パラジウム（ＩＩ）（０．９０ｇ、１．２６ｍｍｏｌ）、水酸化ヒドラジン（０．０６ｍｌ、１．２３ｍｍｏｌ）、臭化物１（２３．５ｇ、６０．０ｍｍｏｌ）およびテトラヒドロフラン（ＴＨＦ、１８ｍｌ）を加える。混合物を５分間攪拌し、ＴＨＦ（３０ｍｌ）に溶解されたベンゼンボロン酸（７．３０ｇ、６０．０ｍｍｏｌ）、またはベンゼンボロン酸の任意の誘導体、を加える。混合物を攪拌し、出発材料のほとんどが消費されたことを薄層クロマトグラフィーで確認できるまで、１２時間沸点に保つ。冷却後、水とメチルｔ−ブチルエーテルを加え、相分離させる。エーテルにより更に抽出し、混合された有機層を水と食塩水により洗浄し、硫酸ナトリウムで乾燥し、乾燥するまで蒸発させる。残渣を石油エーテルで回収し、シリカのパッドを通して濾過する。生成物をエタノールおよびヘキサンから結晶化させる。

To an aqueous solution (72 ml) of sodium metaborate octahydrate (12.5 g, 45.0 mmol), bis (triphenylphosphine) palladium (II) chloride (0.90 g, 1.26 mmol), hydrazine hydroxide (0. 06 ml, 1.23 mmol), bromide 1 (23.5 g, 60.0 mmol) and tetrahydrofuran (THF, 18 ml) are added. The mixture is stirred for 5 minutes and benzeneboronic acid (7.30 g, 60.0 mmol), or any derivative of benzeneboronic acid, dissolved in THF (30 ml) is added. The mixture is stirred and kept at the boiling point for 12 hours until thin layer chromatography confirms that most of the starting material has been consumed. After cooling, water and methyl t-butyl ether are added and the phases are separated. Further extraction with ether, the combined organic layers are washed with water and brine, dried over sodium sulfate and evaporated to dryness. The residue is collected with petroleum ether and filtered through a pad of silica. The product is crystallized from ethanol and hexane.

Melting point: 75 ° C
C 75 I
Δn = 0.090
Δε = 19
formula:

の化合物を調製する。一般的な方法に類似して、またはスキーム１〜４（以下の表の１７〜４６の化合物については、シクロヘキサン誘導体）に従い、調製する。その部分構造を、以下の表に示す。

Prepare the compound. Prepared analogously to general methods or according to Schemes 1-4 (cyclohexane derivatives for compounds 17-46 in the table below). The partial structure is shown in the following table.

    Table 1. Compound and physical properties

Claims (12)

A compound of the formula I

(Where

L ^1-4 are each independently H or F,
Z ¹ and Z ² are each independently of each other —CO—O—, —O—CO—, —C ₂ F ₄ —, —C ₂ H ₄ —, —CH═CH—, —CF═CF—, -CH = CF -, - CF = CH -, - CH 2 O -, - OCH 2 -, - C≡C- or a single bond,
X is F, Cl, CN, OCN, NCS, SCN, SF ₅ , an unsubstituted alkyl or alkoxy group having 6 or less carbon atoms, a halogenated alkyl group, a halogenated alkenyl group, a halogenated alkoxy group or a halogen An alkenyloxy group,
u is 0, 1, 2 or 3, and v is 1 or 2, provided that u + v is 3 or less. ) The compound according to claim 1, wherein at least one of Z ¹ and Z ² is a single bond. A compound of any one of formulas I1-I5.

( ^Wherein L ^1-8 are each independently H or F, and X has the meaning defined for Formula I). X is F, Cl, CN, CF ₃ , CHF ₂ , OCF ₃ , OCHF ₂ , OCHFHCF ₃ , OCHFHCHF ₂ , OCHFHCH ₂ F, OCF ₂ CH ₃ , OCF ₂ CHF ₂ , OCF ₂ CH ₂ F, OCF ₂ CF _{2 CHF 2, OCF 2 CF 2} CH 2 F, OCFHCF 2 CF 3, OCFHCF 2 CHF 2, OCF 2 CF 2 CF 3, OCF 2 CF 2 CClF 2, OCClFCF 2 CF 3, CH = CF 2, OCH 3, OC claims 1 a ₂ H ₅ or _OC 3 _{H 7} to 3 a compound according to any. The compound according to any one of claims 1 to 4, wherein L ¹ and L ² are F, and L ³ and L ⁴ are H.

The compound according to any one of claims 1 to 5. The compound according to any one of claims 1 to 6, wherein both Z ¹ and Z ² are a single bond.   Use of a compound according to any of claims 1 to 7 for electro-optical purposes.   A liquid crystal medium comprising at least one compound according to claim 1 and containing at least two compounds.   10. A method for preparing a liquid crystal medium according to claim 9, comprising a step of mixing at least one kind of the compound according to any one of claims 1 to 7 with another liquid crystal compound.   11. A process according to claim 10, wherein the compound is mixed while adding further additives.   An electro-optical liquid crystal display comprising a medium containing at least one compound according to claim 1.