JP2002069040A - Optically active fluorine-substituted biphenyl derivatives - Google Patents

Abstract

[PROBLEMS] To provide an antiferroelectric liquid crystal composition having a low threshold voltage, being stable to light, heat, etc., and having good compatibility with other liquid crystal components. Provided are an excellent liquid crystal compound useful as a component, an antiferroelectric liquid crystal composition having a small spontaneous polarization value at room temperature and a high-speed response, and a liquid crystal display device capable of performing gradation display using the composition. An optically active fluorine-substituted biphenyl derivative represented by the formula (1), a liquid crystal composition containing the compound, and a liquid crystal display device using the composition. Wherein R ¹ is C 2-20 alkyl, alkanoyloxy or alkoxy, R ² is C 3-15 straight chain alkyl,
R ³ is methyl, trifluoromethyl or ethyl, X, Y
Is H or F, X and Y are not H at the same time, and * indicates an asymmetric carbon. The liquid crystal device using this composition has a good V-shaped electro-optic response waveform over a wide temperature range including room temperature, and can obtain a gradation by changing the voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel optically active fluorine-substituted biphenyl derivative, a liquid crystal composition containing this derivative, and a liquid crystal which can be suitably used for a liquid crystal display device, especially an antiferroelectric liquid crystal display device. The present invention relates to a liquid crystal display device using the composition.

[0002]

2. Description of the Related Art Liquid crystal compounds are widely used for display devices. Many liquid crystal display elements are twisted nematic (TN), which is a display using a nematic phase.
A super twisted nematic method (STN method) in which the twist angle is 200 ° or more, and an active matrix method using a thin film transistor (TFT) or the like as a switching element in each pixel. These liquid crystal display devices are inferior in electro-optical response speed as compared with a display using a cathode ray tube (CRT). On the other hand, a display device using an antiferroelectric phase is superior to a display device using a nematic phase, such as a high-speed response and a wide viewing angle. It has been actively researched and its development has been attempted.

The antiferroelectric phase has three stable states, two ferroelectric states and one antiferroelectric state, and uses the three-state switching for display. The feature of this three-state switching is that it exhibits a steep threshold characteristic and a wide optical hysteresis at the transition between the antiferroelectric phase and the ferroelectric phase (ADL Chandani et al., Journal of Applied Physics, Vol. 27, No. 5, L72
9, 1988). By combining this feature with the simple matrix method, a display having both a wide viewing angle and a high contrast can be performed.

Recently, an antiferroelectric liquid crystal compound having no threshold value (Kairai, J. Mater. Chem., 6
(4), p. 671, 1996). These liquid crystals exhibit a V-shaped optical response, and a display element capable of easily performing gradation display, which is difficult with the simple matrix system, can be realized by combination with an active matrix system such as a TFT (Japanese Patent Laid-Open No. 7-64056).

[0005]

When an antiferroelectric liquid crystal compound having three stable states is used for a display device, the operating temperature range is wide, including around room temperature, and the threshold voltage is low. Characteristics must be satisfied.
Further, it needs to have stability against light, heat, and the like as in a general liquid crystal compound. Furthermore, when preparing a liquid crystal composition, it is necessary that the compatibility with other components be good. An object of the present invention is to provide an excellent liquid crystal compound which is useful as a component of an antiferroelectric liquid crystal composition and solves the above problems.

[0006]

Means for Solving the Problems The present inventors searched for an optically active compound having a fluorine-substituted biphenyl skeleton as a core structure, and found a compound that can be suitably used as a component of a liquid crystal composition in an antiferroelectric phase. Thus, the present invention has been completed. Many of the compounds have a liquid crystal phase, particularly an antiferroelectric phase, and thus are useful as components of a liquid crystal composition having an antiferroelectric phase.
In addition, even if it does not show an antiferroelectric phase, it can be used by sharing with other appropriate antiferroelectric phase compounds because it has potential antiferroelectricity.

The present invention relates to an optically active fluorine-substituted biphenyl derivative, a liquid crystal composition containing the same, and a liquid crystal display device using the liquid crystal composition. The present invention relates to the following << 1 >>
This is indicated by << 8 >>. << 1 >> Equation (1)

[0008]

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[0009] (wherein, R ¹ is alkyl of 2 to 20 carbon atoms, alkanoyloxy or alkoxy, R ²
Is a straight-chain alkyl having 3 to 15 carbon atoms, R ³ is methyl, trifluoromethyl or ethyl, X and Y are each independently hydrogen or fluorine, but X and Y are simultaneously hydrogen. , And * indicates an asymmetric carbon). <2> The optically active fluorine-substituted biphenyl derivative according to <1>, wherein in the formula (1), R ³ is methyl. <3> The optically active fluorine-substituted biphenyl derivative according to <1>, wherein in the formula (1), R ³ is trifluoromethyl. << 4 >> In the formula (1), R ¹ is linear alkyl having 2 to 20 carbon atoms, alkanoyloxy or alkoxy, R ² is linear alkyl having 3 to 15 carbon atoms, and R ³ is methyl. Wherein X is fluorine and Y is hydrogen; <1> the optically active fluorine-substituted biphenyl derivative; << 5 >> In the formula (1), R ¹ is linear alkyl having 2 to 20 carbon atoms, alkanoyloxy or alkoxy, R ² is linear alkyl having 3 to 15 carbon atoms, and R ³ is methyl. Wherein X is hydrogen and Y is fluorine; <1> the optically active fluorine-substituted biphenyl derivative; << 6 >> In the formula (1), R ¹ is linear alkyl having 2 to 20 carbon atoms, alkanoyloxy or alkoxy, R ² is linear alkyl having 3 to 15 carbon atoms, and R ³ is methyl. Wherein X is fluorine and Y is fluorine; <1> the optically active fluorine-substituted biphenyl derivative; << 7 >> A liquid crystal composition containing at least one optically active fluorine-substituted biphenyl derivative according to any one of <1> to <6>. << 8 >> A liquid crystal display device using a liquid crystal composition containing at least one optically active fluorine-substituted biphenyl derivative according to any one of <1> to <6>.

Preferred structures of the compound of the present invention are represented by the following formulas (1-1), (1-2) and (1-3).

[0011]

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In these formulas, R ¹ has 2 to 2 carbon atoms.
Alkyl, alkanoyloxy or alkoxy having 0 is preferable, and among them, linear alkyl, alkanoyloxy or alkoxy having 5 to 16 carbon atoms is more preferable. As specific alkyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl and hexadecyl are preferred. Specific alkanoyloxy as pentanoyloxy, hexanoyloxy, heptanoyloxy, octanoyloxy, nonanoyloxy,
Decanoyloxy, undecanoyloxy, dodecanoyloxy, tridecanoyloxy, tetradecanoyloxy, pentadecanoyloxy and hexadecanoyloxy are preferred. Specific alkoxy as pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy,
Dodecyloxy, tridecyloxy, tetradecyloxy, pentadecyloxy, hexadecyloxy are preferred.

The optically active group and the core structure of the compound of the present invention are linked by an ester. Therefore, an optically active secondary alcohol is used as a raw material for producing an optically active site. Specific optically active alcohols include S-form and R-form.
-Pentanol, 2-hexanol, 2-heptanol, 2-octanol, 2-nonanol, 2-decanol, 2-undecanol, 2-dodecanol, 1,1,
1-trifluoro-2-pentanol, 1,1,1-trifluoro-2-hexanol, 1,1,1-trifluoro-2-heptanol, 1,1,1-trifluoro-
2-octanol, 1,1,1-trifluoro-2-nonanol, 1,1,1-trifluoro-2-decanol, 1,1,1-trifluoro-2-undecanol,
1,1,1-trifluoro-2-dodecanol, 3-hexanol, 3-heptanol, 3-octanol,
-Nonanol, 3-decanol, 3-undecanol,
3-Dodecanol is preferred.

Next, production examples of the compound of the present invention will be shown. The compound represented by the general formula (1) of the present invention can be produced by the following route. That is, magnesium is allowed to act on the aryl bromide (a) to prepare a Grignard reagent, and trimethyl borate is added thereto, followed by post-treatment with hydrochloric acid to obtain the corresponding boric acid (b). Benzylation of the 4-bromophenol derivative (c) with benzyl bromide and a base gives (d). (B) and (d) are described, for example, in Organic Synthesis, Vol. 62, p. 6066, 1997.
When a cross-coupling reaction is carried out according to the method of 1992, a fluorine-substituted 4-alkyl-4′-benzyloxybiphenyl derivative (e) is selectively obtained. (E) using a catalyst such as palladium carbon or palladium hydroxide carbon,
Hydrogenolysis gives debenzylated (f). The optically active benzoic acid derivative (Ph1) can be easily synthesized by the method described in Japanese Patent Publication No. Hei 8-2511760. Specifically, bromination of p-toluoyl chloride gives p-
Bromomethylbenzoic acid chloride is obtained. (Ph1) can be synthesized by esterification of p-bromomethylbenzoic acid chloride with an optically active secondary alcohol. (1) can be produced by subjecting (f) and (Ph1) to a general etherification method using a base such as sodium hydroxide, potassium hydroxide, sodium hydride and sodium methoxide.

[0015]

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[0016]

The present invention will now be described with reference to Examples and Comparative Examples.
The compound will be described in more detail. The following examples and
In the Comparative Examples and Comparative Examples, various physical property values were measured by the following methods.
Was. Phase transition temperature: Place the sample on a glass slide and cover
And place it on a hot stage under a polarizing microscope.
The temperature was measured at a rate of ° C./min. In phase transition, SA
Smectic A phase, SC^*Is chiral smectic C
Phase, SCA^*Indicates antiferroelectric phase, Iso indicates isotropic liquid
You. Melting point: 1 ° C./mi using differential scanning calorimetry (DSC)
The temperature was raised at n. The fact that the compound of the present invention exhibits antiferroelectricity can be confirmed by using a polarizing microscope.
In addition to observing the structure below,
Of apparent tilt angle vs. applied voltage hysteresis
And the appearance of three-state switching in electro-optical response
Therefore, it was confirmed. Electro-optical response: Oriented, with electrode spacing of 5 μm
Each composition was injected into a cell, and Vpp was 20 V, 1 kHz.
Measured from the change in transmitted light intensity when a square wave is applied
Was. Threshold voltage: Polyimid on glass substrate with transparent electrode
Rubbing one of the pair of substrates coated with
Facing each other and the electrode spacing is 5 μm.
Created. Inject liquid crystal composition in isotropic phase into this cell
And then slowly cool down the SCA ^*Phase. 50m to this liquid crystal cell
Response and applied voltage when applying a triangular wave of
Was observed with a dual phenomenon oscilloscope. Antiferroelectric phase and fertility
The threshold voltage of the transition to and from the electrical phase depends on the threshold
Measured from the change in optical response under an appropriately determined applied voltage
Was.

Example 1 Preparation of 1-methylheptyl = 4- (3'-fluoro-4'-octyloxybiphenyl-4-yloxymethylene) benzoate [4] (First step) 4-bromo-2-fluoro Phenol 10
0 g, 94 g of octyl bromide and 121 g of potassium carbonate were refluxed in dimethylformamide for 5 hours. Water (1 L) and toluene (1 L) were added, the layers were separated, and the toluene layer was dried over anhydrous magnesium sulfate. After evaporating the solvent, the residue was purified by distillation under reduced pressure to obtain 150 g of 3-fluoro-4-octyloxybromobenzene. Boiling point (1.3 × 10 ⁵ Pa) 13
3-135 ° C

(Second Step) 6.4 g of magnesium was suspended in 20 ml of tetrahydrofuran, and a solution of 73 g of 3-fluoro-4-octyloxybromobenzene in 300 ml of tetrahydrofuran was added dropwise to prepare a Grignard reagent. Trimethyl borate 9 in Grignard reagent
8 g was added dropwise and the mixture was stirred at room temperature for 2 hours. 6N hydrochloric acid 30
The reaction was terminated by adding 0 ml, and extracted with 300 ml of ether. The ether layer was separated and the ether was distilled off to give 5
3.6 g of 3-fluoro-4-octyloxyphenylboronic acid were obtained. This was used for the next reaction without purification.

(Third step) 53.6 g of 3-fluoro-4-octyloxyphenylboronic acid, 63.2 g of 4-benzyloxybromobenzene, 31.8 g of sodium carbonate
g, tetrakistriphenylphosphine palladium
3 g in 10 ml of dimethoxyethane, 75 g of water
Refluxed for hours. The reaction mixture was poured into water, and the resulting suspension was filtered to obtain crude crystals. The crude crystals were dissolved in chloroform and purified by silica gel column chromatography. After the solvent was distilled off, the concentrate was recrystallized from acetone to give 52 g of 3-fluoro-4-octyloxy-4′-.
Benzyloxybiphenyl was obtained. 112.4 ° C

(Fourth Step) In a solution of 300 ml of tetrahydrofuran, 52 g of 3-fluoro-4-octyloxy-4'-benzyloxybiphenyl was hydrogenated at normal pressure using 1.1 g of palladium hydroxide carbon. Hydrogen absorption ceased after about 20 hours. After removing the catalyst and concentrating, recrystallization from chloroform gave 28 g of 3-fluoro-
4-Octyloxy-4'-hydroxybiphenyl was obtained. 133.3 ° C

(Fifth Step) To 40 g of p-toluoyl chloride heated to 120 ° C., 42 g of bromine were added dropwise over 1 hour. After stirring for an additional hour, the mixture was distilled under reduced pressure. 170 ~
The fraction at 172 ° C. (2.7 × 10 ⁶ Pa) was further rectified to obtain 15 g of p-bromomethylbenzoic acid chloride. 54-55 ° C

(Sixth step) 210 g of p-bromomethylbenzoic acid chloride and 140 g of (R) -2-octanol were placed in 2 L of dry toluene while bubbling nitrogen through nitrogen.
Stirred for hours. The toluene and unreacted (R) -2-octanol were distilled off under reduced pressure to obtain 204 g of (R) -4-bromomethylbenzoic acid = 1-methylheptyl ester. This was used for the next reaction without purification.

(Seventh step) 7 g of 3-fluoro-4-octyloxy-4'-hydroxybiphenyl, 7.2 g of p-bromomethylbenzoic acid = 1-methylheptyl and 1.5 g of potassium hydroxide are added in 100 ml of dimethylformamide. Refluxed for 5 hours. Water was added to the reaction mixture, and the mixture was extracted with toluene. The toluene layer was washed several times with water and dried over anhydrous magnesium sulfate. After the toluene was distilled off, the residue was recrystallized from acetone through silica gel column chromatography, and 5 g of 1-methylheptyl = 4- (3′-fluoro-4′-octyloxybiphenyl-4-yloxymethylene) benzoate [ 4] was obtained.

Example 2 Preparation of 1-methylheptyl 4- (3-fluoro-4'-octyloxybiphenyl-4-yloxymethylene) benzoate [22] (First step) 259 g of 4-bromophenol, bromide 311 g of octyl and 308 g of potassium carbonate were refluxed in 1 L of dimethylformamide for 5 hours. Water 1L, toluene 1
L was added and the mixture was separated. The toluene layer was washed with 6N hydrochloric acid and saturated aqueous sodium carbonate, and dried over anhydrous magnesium sulfate. The residue obtained by distilling off the solvent was distilled under reduced pressure to give 30
0 g of 4-octyloxybromobenzene was obtained. Boiling point (1.6 × 10 ⁶ Pa) 144-145 ° C.

(Second stage) 17 g of magnesium was suspended in 50 ml of tetrahydrofuran, and 200 g of 4-octyloxybromobenzene was added to 50 ml of tetrahydrofuran.
A Grignard reagent was prepared by dropwise addition of the 00 ml solution.
To this Grignard reagent, 100 g of trimethyl borate was added dropwise and stirred at room temperature for 2 hours. The reaction was terminated by adding 500 ml of 6N hydrochloric acid and extracted with 500 ml of ether. The ether layer was separated, 800 ml of heptane was added to the concentrate from which ether was distilled off, and the mixture was recrystallized at -10 ° C.
1 g of 4-octyloxyphenylboronic acid was obtained. Melting point 84 ° C

(Third Step) 1 kg of 4-bromo-2-fluorophenol, 1.2 kg of benzyl bromide and 150 g of tetraethylammonium bromide in toluene 3.5
While stirring the L solution vigorously,
g of water in 330 ml solution were added all at once. 80 ° C the mixture
For 8 hours. After 1.5 L of water was added for liquid separation, the toluene layer was washed with 500 ml of saturated saline and dried over anhydrous magnesium sulfate. The solution obtained by filtering the drying agent was subjected to silica gel chromatography to remove impurities, and the obtained solution was concentrated to obtain colorless crude crystals. The crude crystals were recrystallized from ethanol to obtain 990 g of 3-fluoro-4-benzyloxybromobenzene. Melting point 6
8.4 ° C

(Fourth step) 11.9 g of 4-octyloxyphenylboronic acid, 12.7 g of 3-fluoro-4-benzyloxybromobenzene, 5.7 sodium carbonate
g, palladium acetate 0.03 g, and triphenylphosphine 0.11 g were refluxed in 70 ml of n-propanol and 7 ml of water for 1.5 hours. The reaction mixture was poured into 300 ml of water, and the resulting suspension was filtered to obtain crude crystals. The crude crystals were dissolved in chloroform, impurities were removed by silica gel column chromatography, and the eluted solution was concentrated.
The concentrate was recrystallized from acetone to obtain 11 g of 4-octyloxy-4′-benzyloxy-3′-fluorobiphenyl. Melting point 103.8 ° C

(Fifth step) 4-octyloxy-4'-
11 g of benzyloxy-3′-fluorobiphenyl, tetrahydrofuran 10 containing 0.2 g of palladium hydroxide carbon
The 0 ml solution was hydrogenated at normal pressure. Hydrogen absorption ceased after about 6 hours. After removing the catalyst and concentrating, the residue was recrystallized from chloroform to obtain 6 g of 4-octyloxy-4′-hydroxy-3′-fluorobiphenyl. Melting point 11
5.6 ℃

(Sixth step) 4-octyloxy-4'-
Hydroxy-3'-fluorobiphenyl 1.4 g, p-
1.6 g of bromomethylbenzoic acid = 1-methylheptyl ester and 0.3 g of potassium hydroxide were refluxed in 30 ml of dimethylformamide for 3 hours. Water was added to the reaction mixture, and the mixture was extracted with toluene. The toluene layer was washed several times with water and dried over anhydrous magnesium sulfate. After the toluene was distilled off, the residue was recrystallized from acetone through silica gel column chromatography to obtain 0.5 g of 1-methylheptyl = 4.
-(3-Fluoro-4'-octyloxybiphenyl-
4-yloxymethylene) benzoate [22] was obtained.

Example 3 1-methylheptyl = 4- (3,3'-difluoro-
Preparation of 4'-octyloxybiphenyl-4-yloxymethylene) benzoate [40] (First step) 29.1 g of 3-fluoro-4-octyloxyphenylboronic acid, 29 of 3-fluoro-4-benzyloxybromobenzene 29 .1 g, sodium carbonate13.
1 g, 0.7 g of palladium acetate, 2.4 g of triphenylphosphine were added to 200 ml of n-propanol and 38 ml of water.
Refluxed for 3.5 hours. The reaction mixture was poured into 500 ml of water, and the suspension was filtered to obtain crude crystals. The crude crystals were dissolved in chloroform, and impurities were removed by silica gel column chromatography. After evaporating the solvent, the concentrate was recrystallized from acetone to obtain 11 g of 3-fluoro-4-octyloxy-4′-benzyloxy-3′-fluorobiphenyl.

(Second step) 25 g of 3-fluoro-4-octyloxy-4'-benzyloxy-3'-fluorobiphenyl was dissolved in a 250 ml solution of tetrahydrofuran.
Hydrogenation was performed at normal pressure using 0.5 g of palladium hydroxide carbon. Hydrogen absorption ceased after about 6 hours. After removing the catalyst and concentrating, the residue was recrystallized from chloroform to obtain 18 g of 3-fluoro-4-octyloxy-4′-hydroxy-3′-fluorobiphenyl. Melting point 110 ° C

(Third step) 7 g of 3-fluoro-4-octyloxy-4'-hydroxy-3'-fluorobiphenyl, 8.2 g of p-bromomethylbenzoic acid = 1-methylheptyl and 1.4 g of potassium hydroxide were added. The mixture was refluxed in 150 ml of dimethylformamide for 3 hours. Water was added to the reaction solution, and the mixture was extracted with toluene. The toluene layer was washed several times with water and dried over anhydrous magnesium sulfate. After the toluene was distilled off, the impurities were removed by silica gel column chromatography, and recrystallized from acetone, and 1.9 g of 1-methylheptyl = 4- (3,3′-difluoro-4′-octyloxybiphenyl-4-methyl-4-methyl-3-phenyl) was obtained. (Iloxymethylene) benzoate [40] was obtained.

Example 4 Preparation of 1-methylheptyl = 4- (3-fluoro-4'-decanoyloxybiphenyl-4-yloxymethylene) benzoate [122] (First step) 200 g of 4-bromophenol was dissolved in toluene. It was dissolved in 400 ml of triethylamine and 250 ml of triethylamine, and 224 g of n-decanoic acid chloride was added thereto and refluxed for 4 hours. 300 ml of toluene and 500 ml of 6N hydrochloric acid were added, and the separated toluene layer was washed with 300 ml of 6N hydrochloric acid, 300 ml of saturated sodium carbonate solution and 100 ml of water in this order, and dried over anhydrous magnesium sulfate. After evaporating the solvent, the residue was distilled under reduced pressure to obtain 391 g of 4-decanoyloxybromobenzene. Boiling point (19.9 × 10 ⁶ Pa) 280
~ 290 ° C

(Second step) 13 g of magnesium was suspended in 50 ml of tetrahydrofuran, and a Grignard reagent was prepared by dropping a solution of 150 g of 3-fluorobenzyloxybromobenzene in 500 ml of tetrahydrofuran. Thereto was added 81 g of trimethyl borate, and the mixture was stirred at room temperature for 1 hour, and 400 ml of 6N hydrochloric acid was added to terminate the reaction. The mixture was extracted with 500 ml of ether, and the ether layer was dried over anhydrous magnesium sulfate. After ether was distilled off under reduced pressure, the residue was recrystallized from toluene to give 4-benzyloxy-
97 g of 3-fluorophenylboronic acid was obtained. Melting point 11
0-111 ° C

(Third step) 15 g of 4-benzyloxy-3-fluorophenylboronic acid, 20 g of 4-decanoyloxybromobenzene, 12.6 g of sodium carbonate, 0.47 g of triphenylphosphine, and 0.1 g of palladium acetate.
Using 13 g, 350 ml of n-propanol and 40 ml of water, 4-decanoyloxy-4′-benzyloxy-3′-fluorobiphenyl was obtained in the same manner as in the fourth step of Example 2. This was subjected to hydrogenolysis in the same manner as in the fifth step of Example 2 to obtain 8 g of 4-decanoyloxy-4′-hydroxy-3′-fluorobiphenyl. Melting point 221-226 ° C

(Fourth step) 4-decanoyloxy-4 '
3.4 g of -hydroxy-3'-fluorobiphenyl was dissolved in 50 ml of tetrahydrofuran, and 0.48 g of sodium hydride (purity: 60%) was added thereto, followed by stirring at room temperature for 30 minutes. There (R) -4-bromomethylbenzoic acid =
A solution of 3.1 g of 1-methylheptyl ester in 150 ml of dimethylformamide was added, and the mixture was stirred at 60 ° C. for 5 hours. Toluene and water were added, and the separated toluene layer was washed several times with water and dried over anhydrous magnesium sulfate. After distilling off the solvent, impurities were removed by silica gel chromatography, and further recrystallized from a mixed solvent of heptane-ethyl acetate, and 2 g of 1-methylheptyl = 4- (3-fluoro-4′-decanoyloxybiphenyl) was obtained. -4-yloxymethylene) benzoate [122] was obtained.

In the same manner as in Examples 1 to 3, the formula (1)
Can be produced. The structure and phase transition temperature (° C.) of the compound are shown.

[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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Comparative Example 1 (Comparative compound) Patent publication 2511760 exemplifies a compound [A] which is not substituted by fluorine. Its phase transition temperature is Cr 58.8 S3 ^* 106.0 SH ^*
Although it is described as 134SC ^* 134.8Iso, the present inventors have conducted detailed phase identification and found that this compound has an antiferroelectric phase, and the actual phase series and phase transition temperature are Cr 72 SCA ^*. 134 SC ^* 136 Iso
Was confirmed.

[0052]

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(Comparison of Composition Properties) A composition containing the compound of the present invention was prepared. A uniform composition could be prepared without phase separation. Further, for comparison with these compositions, compositions containing a comparative compound [A] not substituted with fluorine were prepared and a comparative experiment was performed.

[0054]

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Composition ratio of composition Composition (MIX1) Compound [4] 50 wt% Compound [MHPOBC] 50 wt% Composition (MIX2) Compound [22] 50 wt% Compound [MHPOBC] 50 wt% Comparative composition (MIX3) Compound [MIX3] A] 50wt% Compound [MHPOBC] 50wt%

Phase transition temperature of composition (° C.) Composition (MIX1) Melting point is below room temperature SCA * 99.2 SC * 105.2 SA 126.1 Iso Composition (MIX2) Melting point is below room temperature SCA * 98.3 SC * 103.9 SA 127.3 Iso Comparative composition Compound (MIX3) Melting point is below room temperature SCA * 119.5 SC * 125.0 SA139.6 Iso The threshold voltages at 85 ° C. and 75 ° C. of the compositions (MIX1) and (MIX2) and the comparative composition (MIX3) were measured.

Threshold voltage of composition Temperature 85 ° C. 75 ° C. Composition (MIX1) 2.09 V / μm 3.22 V / μm Composition (MIX2) 1.53 V / μm 2.14 V / μm Comparative composition (MIX3) ) 3.63 V / μm 3.81 V / μm

A composition containing the compound of the present invention (MIX
1) and (MIX2) have lower threshold voltages at each measurement temperature than the comparative composition (MIX3). That is, it can be seen that adding the compound of the present invention to the composition has an effect of lowering the threshold voltage directly related to the driving voltage of the antiferroelectric device.

[0059]

Many of the compounds of the present invention not only exhibit stable antiferroelectricity, but also have a higher anti-ferroelectric property than the unsubstituted compound due to the fact that the optimum position of the biphenyl moiety as the main skeleton is substituted with fluorine. The threshold voltage that directly affects the driving voltage of the ferroelectric element is reduced. Further, it is stable against heat, light, and the like, and has excellent compatibility with other liquid crystal components.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junichi Inagaki 5-1, Goi Kaigan, Ichihara-shi, Chiba Chisso Petrochemical Co., Ltd. Functional Materials Research Laboratory (72) Inventor Hiromichi Inoue 5-1, Goi-kaigan, Ichihara-shi, Chiba Chisso Petrochemical Co., Ltd. Functional Materials Research Laboratory (72) Inventor Eiji Okabe 5-1, Goi Kaigan, Ichihara City, Chiba Prefecture Chisso Petrochemical Co., Ltd. Functional Materials Research Laboratory F-term (reference) BD01 BD05 BD08 BD19 BD24 CE08 CF08

Claims (8)

[Claims] (1) Formula (1) Wherein R ¹ is alkyl having 2 to 20 carbon atoms, alkanoyloxy or alkoxy, and R ² is 3 to 1 carbon atoms.
5 is a straight-chain alkyl, R ³ is methyl, trifluoromethyl or ethyl, X and Y are each independently hydrogen or fluorine, but X and Y are not hydrogen simultaneously, and * is An optically active fluorine-substituted biphenyl derivative represented by the following formula: 2. The optically active fluorine-substituted biphenyl derivative according to claim 1, wherein in the formula (1), R ³ is methyl. 3. The optically active fluorine-substituted biphenyl derivative according to claim 1, wherein in the formula (1), R ³ is trifluoromethyl. 4. In the formula (1), R ¹ has 2 to 2 carbon atoms.
0 of linear alkyl are alkanoyloxy or alkoxy, R ² is a straight-chain alkyl of 3 to 15 carbon atoms, R ³ is methyl, X is fluorine, claim 1 Y is hydrogen 6. The optically active fluorine-substituted biphenyl derivative according to the above. 5. In the formula (1), R ¹ has 2 to 2 carbon atoms.
0 of linear alkyl are alkanoyloxy or alkoxy, R ² is a straight-chain alkyl of 3 to 15 carbon atoms, R ³ is methyl, X is hydrogen, according to claim 1 Y is fluorine 6. The optically active fluorine-substituted biphenyl derivative according to the above. 6. In the formula (1), R ¹ has 2 to 2 carbon atoms.
0 of linear alkyl are alkanoyloxy or alkoxy, R ² is a straight-chain alkyl of 3 to 15 carbon atoms, R ³ is methyl, X is fluorine, claim 1 Y is fluorine 6. The optically active fluorine-substituted biphenyl derivative according to the above. 7. A liquid crystal composition comprising at least one optically active fluorine-substituted biphenyl derivative according to claim 1. 8. A liquid crystal display device using a liquid crystal composition containing at least one optically active fluorine-substituted biphenyl derivative according to claim 1. Description: