JP2002012871A - Liquid crystal compound, liquid crystal medium and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal medium having a wide nematic phase range, low viscosity and optical anisotropy suitable for display mode and suitable for a PDLC. SOLUTION: The liquid crystal medium contains a dielectrically positive liquid crystal component having a Δn larger than 0.30 at 20 deg.C and 589.3 nm and expressed by general formula I (R1 and R2 are each a substituted/ unsubstituted alkyl, Cl, OCF3, CN, NCS or F; Z11 and Z12 are each CH=CH, CF=CH, CF=CF, single bond, a group of formula III to XVII or formula XVIII to XX; X2 is CN, F or Cl and (n1) is 0 or 1)and a dielectrically positive compound comprising a biphenyl or terphenyl compound having a polar substituent on the terminal and expressed by general formula II.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal compound, a liquid crystal medium and a liquid crystal display containing these media,
In particular, it relates to displays of the OCB type and composite systems such as PDLC, and most preferably of these, holographic PDLC.

[0002]

Problems to be Solved and Prior Art Liquid crystal displays (LCDs) are widely used to display information. The electro-optical modes used include, for example, twisted nematic (TN), super twist nematic (S
TN) and voltage-controlled birefringence (ECB) modes with various variants thereof and others. In addition to those modes that use an electric field that is almost perpendicular to the substrate, especially the liquid crystal layer, there are electro-optical modes that use an electric field that is almost parallel to the substrate, especially the liquid crystal layer, such as an in-plane switching (IPS) mode (eg, DE 40 00 451 and EP 0 588 568).

[0003] To obtain a uniform alignment of the liquid crystal material, a composite system of low molecular weight liquid crystal material with a polymer material, in addition to a variety of different modes, typically using a liquid crystal medium oriented on a pre-treated surface. Applications include, for example, polymer dispersed liquid crystal (PDLC), nematic curvilinear aligned phase (NCAP), and poly network (PN) systems, and are disclosed, for example, in WO 91/05029. These composite systems use an electric field almost perpendicular to the liquid crystal layer. LCDs are used for direct-view displays and projection displays. In addition to these LCD applications, in particular LCDs containing complex systems such as PDLCs and in this case so-called holographic PDLs
The C (HPDLC) system is used practically. HP
DLC is Date, Takeuchi, Tanaka, and Kato, Journal
of the SID 7/1 (1999), p. 17 to 22, incorporated and described as a reference. These HPDLC displays utilize Bragg reflection to emit three bright colors, preferably primary colors. This technique produces excellent bright colors without the need for polarizers or color filters.
A monolayer of a periodic structure of polymer and liquid crystal controls the reflection of a particular color. Three primary colors, and consequently three layers are required, one for each color. Each of the three layers must be addressed independently. This requires three sets of HPDLC films, each with a corresponding electrode. This large number of layers and corresponding electrodes is difficult to achieve in high yields in mass production, but can be beneficially reduced if dual frequency drive is used.

For complex systems, the liquid crystals used need to have a high Δn in order to achieve an effective scattering state and obtain good contrast. In order to improve the so-called axial blur, PDLC systems with a low Δn liquid crystal mixture have been proposed, but in most cases the main problem is to obtain sufficient contrast first. This is especially true for PDLC systems, where Da
te, Takeuchi, Tanaka, and Kanto, Journal of the SI
D 7/1 (1999), p. 17-22. Liquid crystals are generally characterized by having a Δn value of 0.28 at most, or at most 0.29 at most. However, this upper limit is still insufficient and low for many applications. Furthermore, various properties with respect to other properties of the liquid crystal mixture used have only been accepted with compromise. The most typically uncompromising properties are an insufficiently high clearing point, an undesirably narrow range of the nematic phase, a fairly high temperature at which the nematic phase is stable, The anisotropy is too low, the operating voltage is therefore too high, the elastic constant is not favorable, and finally the viscosity value is particularly high or a combination thereof. The good compatibility between the precursors of the polymer of the composite system and the easy phase separation during the formation of the composite system,
Liquid crystals are clearly indispensable for such applications.

[0005] Another potential electro-optical mode used in LCDs is the OCB mode. This mode is described, for example, in Yamaguchi et al., “Wide-Viewing-Angle Displ.
ay Mode for the Active-Matrix LCD Using Bent-Align
ment Liquid-Crystal Cell ”, SID 93, Digest, p.277
(1993). This mode is very promising. It is particularly well suited for direct viewing applications, such as those characterized by having favorable viewing angle dependence. Response times are also very short. However, the response time still needs to be improved for the response of the image interval of the display that changes the gradation. Compared to a conventional TN display in an OCB display, the amount of orientation deformation is much smaller. In a TN display, the orientation is almost parallel to the substrate when the power is turned off, and changes to a direction almost perpendicular to the substrate when an operating voltage is applied, whereas in an OCB display, the orientation is oriented. , Eventually changing in the same direction, but almost starting from a homeotropically bent starting configuration. Therefore, a liquid crystal medium having a higher birefringence is required.

[0006] A terminal isothiocyanate group and, in addition, a terminal phenyl ring having two fluorine atoms in the ortho position are known from DE 40 27 869.7. A liquid crystal mixture consisting mainly of biphenyl and terphenyl substituted with cyano groups at all or ends thereof generally has a moderately high Δε
Values, but have only a limited Δn value and often no longer exhibit sufficient stability at low temperatures, ie, often a smectic phase and / or crystallization occurs. Liquid-crystal mixtures using large amounts of halogenated tolanes with three phenyl rings are almost dielectrically neutral and are described, for example, in European Patent Application No. EP 9911.
1782.1, which is characterized by having a relatively low Δε value that is not suitable for most applications, and often even presents serious problems with respect to the stability of the nematic phase at low temperatures. Thus, for a wide range of nematic phases, low viscosity, appropriate optical anisotropy Δn depending on the display mode, especially for complex applications such as PDLC, for practical applications such as using appropriately high Δn. There is a great need for a liquid crystal medium having suitable properties of the polymer and especially suitable and good compatibility with the polymer precursor for composite systems.

[0007]

Surprisingly, it is possible to realize liquid crystal media having a high Δn and especially useful for complex systems, which do not show the disadvantages of the materials according to the prior art or at least to a very small extent. It has now been found that it only exhibits disadvantages. These improved liquid crystal media according to the invention have been realized using at least two components. The first contains a liquid crystal component (referred to as component A), preferably a strongly dielectrically positive compound having a very high Δn value, preferably a compound of formula I:

Embedded image (Wherein R ¹ is 1 to 12 carbon atoms, preferably 1 to
9 and one or more CH ₂ groups are each independently of one another O, S, CHＣＨCH, CF ＝ CF or CF ₂ to form two oxygen and / or sulfur atoms substituted without adjacent to one another each represent an alkyl, _Cl, an OCF 3, CN, NCS or F, preferably 1 to 7 carbon atoms, n- alkyl preferably having 2-5 carbon atoms Or n-alkoxy,
Alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 carbon atoms, preferably 2 to 5 carbon atoms.

Z ¹¹ and Z ¹² are each independent of each other, and are trans-CH = CH-, -CH = CF
—, —CF ＝ CH—, —CF ＝ CF— or a single bond.

Embedded image Each independently of each other

Embedded image And

Embedded image And n ¹ is 0 or 1.

However, when both Z ¹¹ and Z ¹² are a single bond,

Embedded image At least one ring is substituted by at least one fluorine atom. When at least one Z ¹¹ or Z ¹² is trans-CH = CH-,

Embedded image Is trans-1,4-cyclohexylene, preferably

Embedded image And at the same time the second liquid crystal component (referred to as component B) has a dielectrically positive component, preferably predominantly, most preferably having polar substitutions at all termini, all or part of which is selective Containing a laterally fluorinated biphenyl or terphenyl compound, preferably a compound of formula II:

Embedded image

Wherein R ² has the same meaning as R ¹ in formula I above;

Embedded image Each of the above formulas I

Embedded image And each has the same meaning, and X ² is CN, F or Cl, preferably CN or Cl, most preferably CN.

At least one of Z ¹¹ and Z ¹² is trans —CH = CH—, —CF = CF— or —CH = CF—, or both Z ¹¹ and Z ¹² are single bonds and at least one Wherein the phenyl ring of formula I is replaced by at least one fluorine atom, is novel and is an aspect of the present invention. The compound is prepared from a mesogenic amino compound. As shown in the general reaction scheme described below, the amino group of these compounds
It is converted to an isothiocyanate group using 1,1-thiocarbonyldiimidazole. Liquid crystal compounds for this application include compounds that have a liquid crystal phase alone and compounds that are compatible with mesogenic phases, especially nematic phases, without unacceptably reducing the clearing point. The latter compound has a mesogenic structure and is sometimes called a mesogenic compound. Reaction path diagram I

Embedded image

In the formula, the variables have the same definitions as in the above formula I. (R ¹ is alkyl, alkoxy, alkenyl, alkenyloxy or oxaalkyl) (n ¹ is 0 or 1.) The phenyl ring may be optionally substituted by up to two fluorine atoms. Preferably, the phenyl ring adjacent to the amino group is one or two.
The opposite of the ring, preferably ortho to the amino group, is fluorinated. Alternatively, the isothiocyanate group may be a cyclohexylene ring.

Both Z ¹¹ and Z ¹² are trans-C
Compounds of formula I wherein H = CH- are similarly prepared. These compounds preferably have n ¹ = 1. Amino precursors, which are compounds by direct coupling, are prepared by cross-coupling, see for example Miyaura / Suzuki.
Each suitable precursor is reacted using a palladium catalyzed reaction as shown in Scheme II. Reaction scheme II

Embedded image Wherein the variables are as defined in Reaction Scheme I above.

As shown in Scheme III, the amine of the olefinic compound is prepared using a so-called Heck reaction. Reaction scheme III

Embedded image Wherein the variables are as defined in Formula I above. Preferably, the liquid crystal medium in the present invention contains compound A,
Preferably it consists predominantly and most preferably entirely of the compound of formula I.

As used herein, with respect to a composition, for example, means that a medium or component is referred to as containing the compound or compounds, and preferably at a total concentration of 10% or more. And most preferably contains 20% concentration or more. It is principally mentioned herein that what is mentioned contains 80% or more, preferably 90% or more, and most preferably 95% or more of the compound or compounds concerned. Means As used herein, the term "whole" means that 98% or more, preferably 9%, or more
9% or more and most preferably 100.0%
Or a plurality of corresponding compounds.

Compounds of formula Ia to Ig which are sub-formulas of formula I:

Embedded image Where:

Embedded image Is preferably a phenyl ring substituted by m fluorine atoms, preferably

Embedded image m = 1 or 2, and the other variables are as defined in Formula I above.

A particularly preferred compound of formula Ia is formula Ia-1
To Ia-7:

Embedded image

In the formula, R ¹ has the same meaning as in formula I above. Particularly preferred compounds of formula Ib are compounds of formulas Ib-1 to Ib
Compounds up to -4:

Embedded image In the formula, R ¹ has the same meaning as in Formula I above.

Particularly preferred compounds of formula Ic are those of formula Ic-1
To Ic-5:

Embedded image In the formula, R ¹ has the same meaning as in Formula I above.

A particularly preferred compound of formula Id is formula Id-1
To Id-10:

Embedded image

Embedded image

Wherein R ¹ has the same meaning as in formula I above, preferably n-alkyl having 1 to 5 carbon atoms or n-alkoxy having 1 to 4 carbon atoms or 2 to 2 carbon atoms. 1-E-alkenyl having five.
In a preferred embodiment, the liquid crystal medium of the present invention comprises
B, preferably predominantly and most preferably all of formula II
Consisting of: Preferably the compound of formula II has the subformula I
It is selected from the group of compounds Ia to IIc.

Embedded image

In the formula, R ² is the same as defined in the above formula II. And in the case of sub-formula IIa, it is preferably alkyl or alkoxy, and in the case of sub-formulas IIb and IIc, it is preferably alkyl. In a further preferred embodiment, the liquid-crystal medium comprises a liquid-crystal component C which preferably consists mainly and most preferably all of the compound of the formula III.

Embedded image

Wherein R ³¹ is alkyl or alkoxy having 1 to 7 carbon atoms, alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 carbon atoms. R ³² is Cl, CN or NCS. R
³¹ is preferably n-alkyl, preferably having 3 to 5 carbon atoms, or 1-E having 2 to 5 carbon atoms.
-Alkenyl. R ³² is preferably CN or N
CS, most preferably NCS.

Embedded image Is trans-1,4-cyclohexylene or 1,4-
It is phenylene.

Z ³ is -CH ₂ CH _2- , -COO-,-
C≡C—, —CH ＝ CH— or a single bond, preferably —
CH ₂ CH ₂ — or a single bond and L ^{31 to} L ³⁴ are each independently H or F, preferably up to two of them being H. n ³ is 0 or 1. This compound C is dielectrically positive. Preferably 1 or 2
L ^{31 to} L ³⁴ are F, preferably L ³¹ is F
And L is H, or L ³¹ and L ³³ are F, or L ³² and L ³⁴ are F and all others are H.

Component C is used in a concentration of from 0 to 30%, preferably from 0 to 20%, more preferably from 0 to 10%, based on the whole. Optionally, the liquid-crystalline medium of the present invention further comprises a component D, which is a dielectrically neutral component, preferably comprises a dielectrically neutral compound of the formula IV, and more preferably consists thereof.

Embedded image Wherein R ⁴¹ and R ⁴² are independently of each other carbon atom 1
~ 7 alkyl or alkoxy, or 2 carbon atoms
-7 alkenyl, alkenyloxy or alkoxyalkyl.

[0026]

Embedded image Are independently of each other trans-1,4-cyclohexylene, 1,4-phenylene, 3-fluoro-1,4
-Phenylene, 2-fluoro-1,4-phenylene,
2,3-difluoro-1,4-phenylene or 3,5
-Difluoro-1,4-phenylene, preferably trans-1,4-cyclohexylene, 1,4-phenylene or 3-fluoro-1,4-phenylene. Z ⁴ is —COO—, —CH ₂ CH ₂ —, —CHO—, or a single bond, preferably —COO— or a single bond, trans —CH ＝ CH—, —C≡C—. o or p is 0 or 1 independently of each other.

Component D is used in particular for adjusting the phase range and the optical anisotropy of the liquid crystal medium according to the invention. Compounds of the formula III in which both o and p have a value of 1 are particularly suitable for increasing the clearing point of the medium. o and p are both 0
Are particularly suitable for lowering the lower end of the range of the nematic phase. Especially when Z ⁴¹ is -C≡C-
Are useful for adjusting the Δn of the medium. The concentration of the component D contained in the liquid crystal medium of the present invention is preferably 0% to 50%, more preferably 0% to 30%.
And most preferably 0% to 20%, especially 4%
１６16%.

Further optional compounds contained in the liquid crystal medium are trans-stilbenes substituted by a cyano group as represented by formula V:

Embedded image Wherein R ⁵ is the same as defined for R ¹ in formula I above, preferably R ⁵ is n-alkyl or 1-E-alkenyl;

Embedded image Are each independently of the other

Embedded image Has the same definition as

Preferably,

Embedded image It is. n ⁵ is 0 or 1, preferably 0. Optionally, the media of the present invention may further contain a liquid crystal component to adjust physical properties. Such compounds are known to those skilled in the art. Their concentration in the media of the present invention is preferably 0% to 30%, more preferably 0% to 20% and most preferably 5% to 15%.

Preferably, the liquid crystal medium is 50% to 100%,
More preferably comprises 70% to 100% and most preferably 80% to 100% and in this case 90% to 100% of all components A and B, which components A and B are preferably predominant and most preferably all One or more compounds of Formula I and Formula II, respectively.

In a preferred embodiment, the liquid crystal medium of the present application is:
Contains at least 5 groups. Group 1 is 2
Six-membered rings, preferably optionally fluorinated, each bridged by trans-CH = CH- and terminated with N
It is a compound having a 1,4-phenylene ring having a CS group. Group 2 comprises three 6-membered rings, preferably optionally fluorinated, each and directly bonded, with an NCS terminal
It is a compound having a 1,4-phenylene ring having a group. Group 3 is either directly or optionally CH = CH
It is a compound having two 6-membered rings having a cyano group at the terminal, which are linked via a bridge. Group 4 is a compound having three 6-membered rings, preferably 1,4-phenylene rings each directly bonded and having a cyano group at the end. Group 5 is two 6-membered rings that are directly linked and have a terminal NCS group.

The range of concentrations when these groups of compounds are used in liquid crystal media is as follows.

[Table 1] The liquid crystal medium according to the present invention has a temperature of 80 ° C.
Or higher, particularly preferably 100 ° C. or higher, most preferably 110 ° C. or higher and in this case 120 ° C. or higher.

The liquid crystal medium of the present invention has Δn of 0.25 or more, preferably in the range of 0.30 to 0.60,
More preferably in the range from 0.32 to 0.50, most preferably in the range from 0.33 to 0.45 and especially
It is in the range from 0.35 to 0.40. At 1 kHz and 20 ° C., the Δε of the liquid-crystalline medium according to the invention is 6 or more, preferably 10 or more, most preferably 15 or more and especially 19 or more.

Modern liquid crystal media have been limited by low Δε values at high Δn values and vice versa. Conversely, the media of the present invention show that (0.290, 18.0) and (0.3
70, 6.0) located above a straight line passing through the point (Δ
n, Δε). Preferably the sets are (0.290, 20.0) and (0.370,6.
Above the line through (0), most preferably (0.310,
20.0) and above the line through (0.370, 8.0), and especially above the line through (0.350, 18.0) and (0.390, 8.0). Preferably, the nematic phase of the medium according to the invention has a temperature of at least
C., more preferably at least -20.degree. C. to 70.degree. C. and most preferably at least -30.degree. C. to 80.degree.

As used herein, the term dielectrically positive compound refers to a compound having Δε> 1,5. Dielectrically neutral compounds are compounds having -1,5 ≦ Δε ≦ 1,5 and dielectrically negative compounds are compounds having Δε <-1,5. The same goes for the components. Δε is 1 kHz
And at 20 ° C. The dielectric anisotropy of a compound is one of the individual compounds in a nematic predominant mixture.
Determined from the results of the 0% solution. The volumes of the test mixtures are determined in both homeotropic and homogeneous cells. The cell spacing for both types of cells is approximately 10 μm. The applied voltage is a square wave with a frequency of 1 kHz and a root mean square of typically 0.5 V to 1.0 V, but its value is always chosen to be below the capacity threshold of the respective test mixture. It is.

The mixture ZLI- as a dielectrically positive mixture
4792 and compound ZLI-3086 as a dielectrically neutral and dielectrically negative compound, both Merck KGaA, G
Ermany products, each used as a mixture as a host. The permittivity of the compound is determined from the change in the respective value of the host mixture when the compound of interest is added and extrapolated to the 100% concentration of the compound of interest. 20 ° C
The compound having a nematic phase at the measurement temperature is measured as described above, and all others are treated as compounds.

The term threshold voltage is used herein to refer to the optical threshold, unless otherwise specified, and to 10%
Indicating relative contrast (V ₁₀ ), the term saturation voltage refers to optical saturation, and indicates 90% relative contrast (V ₉₀ ). The capacitive threshold voltage (V ₀ , also called Frederick threshold V _Fr ) is used only when explicitly stated. All ranges of variables included in this application include limited values, unless otherwise specified.

Throughout this specification, unless otherwise specified, all concentrations are given in weight percent, each is stated for all mixtures, and all temperatures are in Celsius.
And all temperature differences are in degrees Celsius. All physical properties are described in “Merck Liquid Crystals, P
hysical Properties of Liquid Crystals ”, Status No
v. Determined by 1997, Merck KGaA, Germany and indicated at a temperature of 20 ° C., unless otherwise specified. Optical anisotropy (Δn) is determined at a wavelength of 589.3 nm. The dielectric anisotropy (Δε) is determined at a frequency of 1 kHz. The threshold voltage was determined using a test cell prepared by Merck KGaA, Germany, as well as other electro-optical anisotropies. The test cells for the determination of Δε had a cell spacing of 22 μm.
The electrodes were circular ITO electrodes with an area of 1.13 cm ² and a protective ring. The alignment layer is homeotropic orientation (ε _||) is a lecithin, homogeneous orientation (ε _⊥)
Was polyimide AL-1054 from Japan Synthetic Rubber. The capacity was determined using a frequency response analyzer Solatron 1260 with a sine wave at a voltage of 0.3 V _rms . The light source used for the electro-optical measurement was white light. The experimental equipment used was commercially available equipment from Otsuka, Japan. The characteristic voltage was determined under vertical observation. Threshold _{(V 10)} - tone _{(V 50)} - and saturation _{(V 90),} respectively voltages of 10%, 50% and 90%
Determined relative to constant.

The liquid crystal medium of the present invention may further contain additives and chiral impurities at ordinary concentrations. The total concentration of these additional components ranges from 0% to 1% based on the total mixture.
The range is up to 0%, preferably 0.1% to 6%. The concentrations of the individual components used in each case are preferably in the range from 0.1 to 3%. The concentrations of these and similar additives are not considered in the values and ranges of the concentrations of the liquid crystal components and compounds of the liquid crystal medium of the present application.

In the present invention, the liquid crystal medium of the present invention comprises several components, preferably 3 to 30, more preferably 5 to 2 components.
Consists of 0, most preferably 6-14 compounds. These compounds are mixed in a conventional manner. Generally, the required amount of the compound used in a small amount is dissolved in the compound used in a large amount. Observing the completion of the dissolution process is particularly simple at temperatures above the clearing point of the compounds used at high concentrations. However, in other conventional methods, for example, using so-called premixes, which are homologous or eutectic mixtures of compounds, or using so-called multi-bottle systems, the composition of which can use the mixture itself By doing so, it is also possible to prepare a medium.

By adding suitable additives, the liquid crystal medium of the present invention is modified to have TN-, TN-AMD, ECB
-, VAN-AMD and especially PDLC-, NCAP
-And can be used in all known types of liquid crystal displays that use liquid crystal media, such as examples of complex systems like PN-LCD and especially HPDLC. The melting point T (C, N), the transition T (S, N) from the smectic (S) phase to the nematic (N) phase and the clearing point T (N, I) of the liquid crystal are expressed in units of Celsius.

In the present invention and in particular in the following examples, the structure of the liquid crystal compounds is indicated by abbreviations, also called acronyms. To convert the abbreviation to the corresponding structure, refer to the following two organized tables A and B. All groups C _n H
_{2n + 1} and _C m _{H 2m + 1} are each straight-chain alkyl group having carbon atoms n or m pieces. The interpretation of Table B is self-evident. Table A lists only the abbreviations at the core of the structure. Each compound is represented by a central abbreviation followed by a hyphen and variables specifying the substituents R ¹ , R ² , L ¹ and L ² .

[0043]

[Table 2]

Table A:

Embedded image

[0045]

Embedded image

Table B:

Embedded image

Embedded image

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image

[0051]

Embedded image The liquid crystal medium of the present invention preferably comprises four or more compounds selected from the group of compounds of Tables A and B,
And / or contains five or more compounds selected from the group of compounds in Table B and / or two or more compounds selected from the group of compounds in Table A.

EXAMPLES The following examples illustrate the invention without any limitation. In particular, however, the physical data of the compounds indicated to those skilled in the art which properties and in what range. Therefore, the combination of various properties that are particularly preferably achieved is clarified.

Example 1 2,6-Difluoro- 1 -isothiocyanate- (4-
Preparation of n-pentyl-trans-cyclohexylene) biphenyl 27.4 g of 4- (n-pentyl-trans-cyclohexylene) -phenyl-boronic acid was added to 20.8 g of 4-
Combine with bromine-2,6-difluoroamine and add 21.2
g of sodium carbonate, 2.3 g of tetrakis (triphenylphosphine) palladium (o), 100 ml of toluene and 50 ml of distilled water were combined in a reaction vessel. The material was heated at reflux for 3.5 hours. Completion of the reaction was confirmed using thin layer chromatography. The reaction product was two layers, a clear aqueous layer and a slightly yellow organic layer.
The aqueous layer was separated and extracted twice using 40 ml of toluene each. The organic phases were combined and the solvent was distilled off. The yellow product was purified on silica gel soaked in toluene. Finally, the product was recrystallized with ethanol.

Preparation of 25.3 g of Target Amine Compound The obtained 25.3 g of amine was dissolved in 300 ml of methylene chloride and cooled to 0 ° C. in a reaction vessel under an inert gas. Then 22.1 g of thiocarbonyldiimidazole, dissolved in 200 ml of methylene chloride, were added to the reaction solution. The temperature was kept at 0 and 2 ° C. during the reaction. After the solution of thiocarbonylimidazole has been added, the reaction mixture is removed by removing the cold water bath and removing
Warmed to a temperature of ° C. The mixture was stirred at ambient temperature for 48 hours. It was then cooled again to 0 ° C. and washed 5 times at 0 ° C., each time using 100 ml of distilled water. The solution remaining in methylene chloride was dried over Na ₂ SO ₄ , filtered and evaporated. Dissolve the residue in n-hexane,
The mixture was stirred using silica gel (Merck KGaA, Art. No. 7 734) and 1 g of charcoal (Merck KGaA) for 30 minutes. Then it was filtered and washed. Then the solvent was again distilled off. The residue was recrystallized with a mixture of ethanol and acetone. The solution was cooled to -20 C for crystallization. The crystals were filtered and dried under vacuum (1 mbar) at 20 ° C.

The yield was 14.3 g of 2,6-difluoro-
1-isothiocyanate- (4-n-pentyl-trans-cyclohexylene) biphenyl:

Embedded image It has a melting point (T (C, N)) of 53 ° C. and a clearing point (T
(N, I)) 194.7 ° C.

Example 2 2-Fluoro-1-isothiocyanate- (4-n-pentyl-trans-cyclohexylene) biphenyl was prepared using the method described in Example 1 above.
14.7 g of imidazole dissolved in 100 g of methylene chloride were cooled to 15 ° C. under an inert gas in the reaction solution. 39 g of thiophosgene was added dropwise to the reaction solution within about one hour. During the addition of reagents, the temperature is 15-25 ° C
Was kept in the range. The mixture is then left for 2 hours at about 22 ° C.
At ambient temperature. Subsequently, 14 g of 4-amino-3-fluoro-4-n-pentyl-trans-cyclohexylene) -biphenyl were added and the reaction mixture was stored at ambient temperature (22 ° C.) for 24 hours. The solvent of the mixture after the reaction was distilled off. The residue was dissolved in n-hexane and purified by silica gel (Merck KGaA, Art. No. 7729). The fractions containing the product were evaporated. The residue is n-
Recrystallized from hexane.

The yield was 10.9 g of 2-fluoro-1-isothiocyanate- (4-n-pentyl-trans-cyclohexylene) biphenyl:

Embedded image It has a melting point (T (C, N)) of 90 ° C. and a clearing point (T
(N, I)) 215.5 ° C.

Examples 3 to 23 The following compounds were prepared as in Example 1.

[Table 3]

Examples 24 to 57 The following compounds were prepared as in Example 1.

[Table 4]

[Table 5]

Examples 58-91 The following compounds were prepared as in Example 1.

[Table 6]

[Table 7]

Example 92 E-1- (2,6-difluoro- (trans-4-n-
Pentyl-cyclohexylene-phenyl) -2- (3,
5-difluoro-4-isothiocyanate-phenyl)
-Preparation of ethene E-1- (2,6-difluoro- (trans-4-n-
Pentyl-cyclohexylene-phenyl) -2- (3,
5-difluoro-4-isothiocyanate-phenyl)
-Ethene was prepared according to Scheme I below.

4.5 dissolved in 50 ml of methylene chloride
g of 1,1-thiocarbonyldiimidazole is cooled to 0 ° C. under an inert gas in a reaction vessel. 5.3 g of E-1
-(2,6-difluoro-4-n-pentyl-trans-cyclohexylene-phenyl) -2- (4-amino-
3,5-Difluoro-phenyl) ethene was prepared on its own, added in small portions and added slowly. The reaction mixture was then warmed to ambient temperature (〜22 ° C.) and stored for 72 hours.
Subsequently, the solvent was distilled off and the residue was dissolved in hot n-hexane and purified on silica gel (Merck KGaA, Art. No. 7729). The eluent was n-hexane. The appropriate fraction was evaporated. The residue was recrystallized from acetone and dried in vacuum.

The yield was 4.3 g of E-1- (2,6-difluoro- (trans-4-n-pentyl-cyclohexylene-phenyl) -2- (3,5-difluoro-4-isothiocyanate-). Phenyl) -ethene.

Embedded image It had a series of phases of crystals, 123.0 ° C. S _A (118.0 ° C., monotropic) N 252.6 ° C.

Examples 93-132 The following compounds were prepared as in Example 92.

[Table 8]

[Table 9]

Examples 133 to 171 The following compounds were prepared as in Example 92.

[Table 10]

[Table 11]

[Table 12]

Examples 172 to 209 The following compounds were prepared as in Example 92.

[Table 13]

[Table 14]

Use Example 1 A practically used liquid crystal medium has the following composition:

[Table 15] This compound has the following properties:

[Table 16]

Use Example 2 The realized liquid crystal medium has the following composition:

[Table 17] This compound has the following properties:

[Table 18]

Use Example 3 The liquid crystal medium realized has the following composition:

[Table 19] This compound has the following properties:

[Table 20]

Use Example 4 The liquid crystal medium realized has the following composition:

[Table 21] This compound has the following properties:

[Table 22]

Use Example 5 The liquid crystal medium realized has the following composition:

[Table 23] This compound has the following properties:

[Table 24]

Use Example 6 The realized liquid crystal medium has the following composition:

[Table 25] This compound has the following properties:

[Table 26]

Use Example 7 The realized liquid crystal medium has the following composition:

[Table 27] This compound has the following properties:

[Table 28]

Use Example 8 The realized liquid crystal medium has the following composition:

[Table 29] This compound has the following properties:

[Table 30]

Use Example 9 The realized liquid crystal medium has the following composition:

[Table 31] This compound has the following properties:

[Table 32]

Use Example 10 The realized liquid crystal medium has the following composition:

[Table 33] This compound has the following properties:

[Table 34]

Use Example 11 The realized liquid crystal medium has the following composition:

[Table 35] This compound has the following properties:

[Table 36]

Use Example 12 The liquid crystal medium realized has the following composition:

[Table 37] This compound has the following properties:

[Table 38]

Use Example 13 The liquid crystal medium realized has the following composition:

[Table 39] This compound has the following properties:

[Table 40]

Use Example 14 The liquid crystal medium realized has the following composition:

[Table 41] This compound has the following properties:

[Table 42]

Use Example 15 The liquid crystal medium realized has the following composition:

[Table 43] This compound has the following properties:

[Table 44]

Use Example 16 The liquid crystal medium realized has the following composition:

[Table 45] This compound has the following properties:

[Table 46]

Use Example 17 The liquid crystal medium realized has the following composition:

[Table 47] This compound has the following properties:

[Table 48]

Use Example 18 The liquid crystal medium realized has the following composition:

[Table 49] This compound has the following properties:

[Table 50]

Use Example 19 The liquid crystal medium realized has the following composition:

[Table 51] This compound has the following properties:

[Table 52]

Use Example 20 The liquid crystal medium realized has the following composition:

[Table 53] This compound has the following properties:

[Table 54]

Use Example 21 The liquid crystal medium realized has the following composition:

[Table 55] This compound has the following properties:

[Table 56]

Use Example 22 The liquid crystal medium realized has the following composition:

[Table 57] This compound has the following properties:

[Table 58]

Use Example 23 The liquid crystal medium realized has the following composition:

[Table 59] This compound has the following properties:

[Table 60]

Use Example 24 The liquid crystal medium realized has the following composition:

[Table 61] This compound has the following properties:

[Table 62]

Use Example 25 The liquid crystal medium realized has the following composition:

[Table 63] This compound has the following properties:

[Table 64]

Use Example 26 The liquid crystal medium realized has the following composition:

[Table 65] This compound has the following properties:

[Table 66]

Use Example 27 The liquid crystal medium realized has the following composition:

[Table 67] This compound has the following properties:

[Table 68]

Use Example 28 The liquid crystal medium realized has the following composition:

[Table 69] This compound has the following properties:

[Table 70]

Use Example 29 The liquid crystal medium realized has the following composition:

[Table 71] This compound has the following properties:

[Table 72]

Use Example 30 The liquid crystal medium realized has the following composition:

[Table 73] This compound has the following properties:

[Table 74]

Use Example 31 The liquid crystal medium realized has the following composition:

[Table 75] This compound has the following properties:

[Table 76]

Use Example 32 The liquid crystal medium realized has the following composition:

[Table 77] This compound has the following properties:

[Table 78]

Use Example 33 The liquid crystal medium realized has the following composition:

[Table 79] This compound has the following properties:

[Table 80]

Use Example 34 The liquid crystal medium realized has the following composition:

[Table 81] This compound has the following properties:

[Table 82]

Use Example 35 The liquid crystal medium realized has the following composition:

[Table 83] This compound has the following properties:

[Table 84]

Use Example 36 The liquid crystal medium realized has the following composition:

[Table 85] This compound has the following properties:

[Table 86]

Use Example 37 The liquid crystal medium realized has the following composition:

[Table 87] This compound has the following properties:

[Table 88]

Use Example 38 The liquid crystal medium realized has the following composition:

[Table 89] This compound has the following properties:

[Table 90]

Comparative Use Example 1 The liquid crystal medium realized has the following composition:

[Table 91] This compound has the following properties:

[Table 92]

Comparative Use Example 2 The realized liquid crystal medium has the following composition:

[Table 93] This compound has the following properties:

[Table 94]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/13 505 G02F 1/13 505 1/1334 1/1334 (71) Applicant 591032596 Frankfighter Str. 250, D-64293 Darmstadt, Federal Republic of Germany (72) Inventor Eike Portsch, Germany Day-64293 Darmstadt Frankfurter Straße 250 (72) Inventor Volker Meyer Germany, Day-64293 Darm Stadt Frankfurter Straße 250 (72) Inventor Joachim Klose, Germany D-64293 Darmstadt Frankfurter Straße 250 (72) Inventor Atsutaka Mabe D-64293 Darm Stadt Frankfurter Straße 250, Germany F term (reference) 2H088 GA01 GA02 GA04 GA10 JA05 JA09 KA09 KA25 KA26 KA27 MA02 2H089 HA04 JA03 KA04 QA16 RA05 RA07 SA03 SA15 SA16 SA17 TA04 4H027 BA01 BB11 BD02 BD03 BD07 BD10 CB05 CD05 CE05 CG04 DC04 CN05 CP05

Claims (10)

[Claims] 1. A liquid crystal display device comprising: a positively dielectric liquid crystal component A;
Said component A comprises one or more compounds of a positive inducing liquid crystal component having terminal isothiocyanate groups and having a Δn greater than 0.30 at strong 20 ° C. and 589.3 nm; A liquid crystal medium comprising a dielectrically positive compound B comprising a biphenyl or terphenyl compound having a polar substituent at the above terminal. 2. The method of claim 1, wherein the dielectrically positive component A is of the formula I: Wherein R ¹ has 1 to 12, preferably 1 to 9 carbon atoms and one or more CH ₂ groups are each independently of the other O, S, CH ＝ CH, CF = CF or CF ₂
The two oxygen atoms and / or sulfur atoms alkyl optionally substituted in a manner which is not adjacent to each other, respectively, _Cl, OCF 3, CN, an NCS or F, ^{Z 11} and ^{Z 12} are mutually respectively Independently, trans -CH = CH-, -CH = CF-, -CF = CH
-, -CF = CF- or a single bond; Each is independent of each other: And And n ¹ is 0 or 1, provided that when both Z ¹¹ and Z ¹² are a single bond, At least one ring is substituted by at least one fluorine atom, and at least one Z ¹¹ or Z ¹² is trans-C
When H = CH-, Is trans-1,4-cyclohexylene, n ¹ is 0 or 1. 2. The liquid crystal medium according to claim 1, comprising one or more compounds represented by the formula: 3. The dielectrically positive component B is of the formula II: Wherein R ² has the same meaning as R ¹ in formula I of claim 2; Each of the formula I of claim 2 And each has the same meaning, and X ² is CN, F or Cl. The liquid crystal medium according to claim 1, comprising one or more compounds represented by the formula: 4. Component A has the formula Ia: 4. A liquid crystal according to claim 1, comprising one or more compounds of the formula wherein the variables have the same meaning as in formula I of claim 2. Medium. 5. Component A is of the formula Ib: The liquid crystal according to any one of claims 1 to 4, comprising one or more compounds represented by the formula: wherein the variables have the same meanings as in formula I of claim 2. Medium. 6. A compound of formula I:(Where R¹Has 1 to 12, preferably 1 to 9 carbon atoms.
And one or more CH₂The groups are mutually independent
And two oxygen and / or sulfur atoms
O, S, CH = CH, CF =
CF or CF ₂Optionally substituted by
, Cl, OCF₃, CN, NCS or F, Z¹¹And Z¹²Are independent of each other,
Trans-CH = CH-, -CH = CF-, -CF = C
H-, -CF = CF- or a single bond;Each independently of one another,AndAnd n¹Is 0 or 1, where Z¹¹And Z¹²When both are single bonds,At least one ring up to at least one fluorine
Substituted by an atom, at least one Z¹¹Or Z¹²Is Trans-C
When H = CH-,Is trans-1,4-cyclohexylene,
Compound. 7. A liquid crystal display comprising the liquid crystal medium according to claim 1. 8. A liquid crystal display according to claim 7, comprising a composite system comprising the liquid crystal medium according to claim 1 and a polymer. 9. The liquid crystal display system according to claim 7, wherein the liquid crystal display system is a holographic display system. 10. Use of the liquid crystal medium according to claim 1 in a liquid crystal system.