JPH04366197A - Liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal composition which gives a quick response to an electric field at room temperature, hardly causes phase decomposition, and allows easy control of the transition temperature and tilt angle by incorporating a specific diene compound and a low-molecular liquid crystal compound in the composition. CONSTITUTION:At least one of diene compounds (e.g. formula VII) which are represented by formula I (wherein r and p are each 2-5; R<1> is a group of formula II, III, IV or V; R<2> is -COOR<3>, -OR<3> or -OCOR<3>; R<3> is a group of formula IV; R<4> and R<5> are each -CH3 or a halogen; a and d are each 0-10; and b is 0.1) is mixed with a low-molecular liquid crystal compound (e.g. formula VIII) to prepare a liquid crystal composition. It is easy for the liquid crystal composition thus obtained to control the transition temperature and tilt angle by the regulation of its composition. To obtain a good contrast by using the liquid crystal composition as a display material, the proportion of the diene compound of the formula I is preferably approx. 40-90wt.%.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a liquid crystal composition, and more specifically, a liquid crystal composition that exhibits a high-speed electric field response at room temperature and can be suitably used in various liquid crystal application fields such as liquid crystal displays. relating to things.

0002

[Prior Art] In order to put ferroelectric liquid crystal into practical use as a display material, it is necessary to: 1) have high-speed response on the order of several μsec, and 2) maintain a ferroelectric liquid crystal phase (for example, SmC* phase) in a wide temperature range including room temperature. 2) High contrast can be obtained (the best tilt angle 2θ is 45°).

[0003] However, since no compound has yet been developed that alone satisfies these performance requirements, it has become common practice to improve the performance by mixing a plurality of compounds. For example, as a method that has become mainstream in recent years,
There is a method described in Japanese Patent No. 37186. This method uses a liquid crystal (host liquid crystal) with a non-optically active SmC phase.
In this method, a chiral dopant (guest) is added. However, chiral dopants, which are guests, generally have poor compatibility with host liquid crystals, and can only be mixed in amounts of a few percent.If the amount is larger than that, some of the chiral dopants will crystallize, causing phase separation. there were.

0004

[Problems to be Solved by the Invention] The present invention has advantages such as exhibiting a high-speed electric field response in the room temperature range, being difficult to cause phase separation, and being able to easily control the transition temperature and tilt angle by adjusting the composition. The object of the present invention is to provide a ferroelectric liquid crystal composition which has excellent practical properties.

[0005]

[Means for Solving the Problems] As a result of intensive research to solve the above problems, the present inventors have discovered that a liquid crystal composition obtained by incorporating a low-molecular liquid crystal compound into a specific diene compound has been developed. Chiral smetic C phase (
The inventors have discovered that the liquid crystal exhibits an excellent ferroelectric liquid crystal that exhibits a SmC* phase) and exhibits high-speed response to changes in electric field, and has completed the present invention based on this knowledge.

That is, the present invention provides a diene compound represented by the following general formula.

[C4] [In the formula, r and p are integers of 2 to 5, R1 is

[Chemical formula 5] However, R2 is -COOR3, -OR3 or -
OCOR3 and R3 is

embedded image where R4 and R5 are -CH3 or a halogen atom, a and d are integers of 0 to 10, and b is 0 or 1. (When R5 is -CH3, d is not 0.)
] and a low molecular weight liquid crystal compound.

The liquid crystal composition of the present invention preferably contains the diene compound in an amount of 5 to 95% by weight. Since this diene compound generally has a wide SmC* phase temperature range, the composition ratio can also be varied widely. Furthermore, since this diene compound has a larger tilt angle than conventional low-molecular liquid crystals, it is also possible to change the tilt angle significantly by adding other compounds. In this respect, when the proportion of the diene compound exceeds 95% by weight, the tilt angle is often too large, and when it is less than 5% by weight, the tilt angle is often too small. Considering that the liquid crystal composition of the present invention is used as a display material, the proportion of the diene compound is preferably 40 to 90% by weight in order to obtain good contrast.

Examples of the diene compound represented by the above general formula of the present invention include the following compounds. Synthesis methods for these compounds are explained in detail in the Examples.

[0009]

[C7]

Next, as the low-molecular liquid crystal compound used together with the diene compound, the following compounds are preferably used.

(1) Typical examples of ferroelectric low-molecular liquid crystal compounds include the following compounds. This compound is commercially available.

[Chemical formula 8]

(2) Representative examples of non-optically active SmC low molecular weight liquid crystal compounds include the following compounds. These compounds are commercially available.

[Chemical formula 9]

(3) Representative examples of optically active low-molecular non-liquid crystal compounds include the following compounds. The method for synthesizing this compound will be explained in detail in the Examples.

[Chemical formula 10]

(4) As a representative example of an antiferroelectric low molecular weight liquid crystal compound, Jpn. J. Appl. Phys, 1988,
27, L729, as shown below.

[Chemical formula 11]

[0015]

[Examples] The present invention will be explained below based on Examples.
The present invention is not limited to this. Note that symbols indicating phase transition behavior have the following meanings. Cry: crystal phase, glass: glass phase, SmC*:
Chiral smectic C liquid crystal phase, Iso: isotropic liquid crystal phase, SmA: smectic A liquid crystal phase, SmX: unidentified smectic liquid crystal phase

Synthesis of diene compound Synthesis of diene compound (B)

[Chemical formula 12]

embedded image 0.1 mol of 1,5-hexadien-3-ol and 0.17 mol of sodium hydride are stirred in 150 ml of THF at room temperature for 1 hour. Next, 1,10-dibromodecane 0
．． 3 mol are introduced and refluxed for 12 hours. Filter the reaction solution,
After concentration, it was purified by column chromatography to obtain the desired ether (1).

[0017]

embedded image 60 mmol of the ether (1) obtained in [1], 4-
A solution of 60 mmol of hydroxybenzoic acid methyl ester and 0.2 mole of potassium carbonate in 150 ml of acetone was added to
Refluxed for an hour. The reaction solution was filtered and concentrated, and then purified by column chromatography to obtain the desired ether (2). (yield 77%)

[0018]

[Chemical formula 15] 30 mmol of the ether (2) obtained in [2], 0.1 mol of sodium hydroxide, 50 ml of ethanol, and 2 ml of water.
Reflux 0 ml of the solution for 30 minutes. The reaction solution was poured into 500 ml of water, the pH was adjusted to 2 with dilute HCl water, the reaction solution was extracted with ether, dried, concentrated, and purified by column chromatography to obtain the desired carboxylic acid derivative (3). Ta. (Yield 96%)

[4] Synthesis of diene compound (B) 43.2 g of the carboxylic acid derivative (3) obtained in [3], 34 ml of thionyl chloride, and 130 ml of toluene were placed in a 1000 ml four-necked flask equipped with a reflux condenser. It was collected and stirred to make a homogeneous solution. Next, add 0.2 pyridine
After adding ml, the reaction temperature was raised to 65°C, and heating and stirring was continued for 4 hours. Thereafter, the reaction mixture was heated under reduced pressure at 65°C for 1 hour and then at 80°C for 30 minutes using an aspirator to remove toluene and remaining thionyl chloride. Then, 170% of toluene was added to the reaction mixture cooled to room temperature.
ml and 11.8 ml of pyridine were added to form a homogeneous solution, and 170 ml of a toluene solution containing 37.9 g of optically active 1-methylheptyl 4'-hydroxybiphenyl-4-carboxylate was added dropwise over 30 minutes with stirring. did. Thereafter, the reaction was completed by stirring overnight at room temperature.

The reaction mixture was filtered to remove precipitated pyridine salt. Next, the filtrate was subjected to rotary evaporation, and the solvent was distilled off under reduced pressure at a bath temperature of 50°C.
．． 8 g of concentrate was obtained. Thereafter, 80 g of methylene chloride was added to this concentrate and stirred to produce a homogeneous and transparent solution. This solution was fractionated by liquid chromatography using a precolumn packed with activated alumina and a main column packed with silica gel. The eluate containing the target compound was applied to a rotary evaporator, and the solvent was distilled off under reduced pressure at a bath temperature of 50°C to obtain the target diene compound (B).
69.2 g (yield: 88%) of crude product was obtained. This crude product was transferred to a 1 liter flask and
Added 0 ml of ethanol. Next, a reflux condenser was attached to the flask, and the mixture was stirred at 70°C for 10 minutes. After confirming that the white solid had completely dissolved to form a homogeneous solution, the flask was naturally cooled to near room temperature. Next, this flask was stoppered to prevent moisture from entering, and then placed in a refrigerator and allowed to stand for 4 hours or more. After this, the flask was taken out, and the precipitated white solid was collected by suction filtration and washed several times with ethanol. Finally, this solid was dried overnight in a vacuum dryer at 50°C to obtain the target diene compound (B). The yield was 57.8g (yield 74
%)Met. This diene compound exhibits liquid crystallinity and exhibits the following phase transition behavior and physical property values.

[0021] Response time: 25μs (52℃) Tilt angle (2θ): 81° (52°C)

Synthesis of diene compound (A)

[Chemical formula 16]

Synthesis Example 1-40 g of carboxylic acid derivative (3) obtained in [3] and optically active 1-methylbutyl 4
'-Hydroxybiphenyl-4-carboxylate 30
．． 44.4 g of the above diene compound (A) was obtained in the same manner as in Synthesis Example 1 except that 5 g was used. This diene compound exhibits liquid crystallinity and exhibits the following phase transition behavior and physical property values.

[0024] Response time: 41μs (68℃) Tilt angle (2θ): 74° (68°C) (Yield 95%)

Synthesis of diene compound (C)

[Chemical formula 17]

[Chemical formula 18]

Synthesis of compound (4) 40 g of 4-hydroxybenzaldehyde, (S)-1-
80 g of methylbutyl-p-toluenesulfonate and 46 g of potassium carbonate were refluxed in acetone for 12 hours, insoluble materials were removed from the reaction solution while hot, and the solvent was distilled off. The residue was purified by column chromatography to obtain 4-(1-methylbutyloxy)benzaldehyde (4).

[0027]

Synthesis of Compound (5) Under an argon atmosphere, 120 g of methoxymethyltriphenylphosphonium bromide was mixed with tetrahydrofuran (TH
F) A hexane solution of butyllithium was added to the solution, and the mixture was stirred at room temperature for 1 hour. Compound (4) was added thereto as a THF solution. Stirring was continued for 2 hours. Wash the reaction solution with water,
Dry with magnesium sulfate and concentrate. The residue was purified by column chromatography to obtain 1-(2-methoxyethenyl)-4-(1-methylbutyloxy)benzene (
5) was obtained.

[0028]

embedded image Synthesis of Compound (6) 100 ml of N,N-dimethylformamide (DMF) was cooled to 0°C. 75 g of phosphorus oxychloride was added dropwise. The mixture was stirred at room temperature for 30 minutes. There, compound (5) was added to DMF.
Added as a solution. The mixture was stirred at 50°C for 1 hour. After cooling, it was poured into an aqueous sodium perchlorate solution, and the resulting iminium salt crystals (6) were collected. It was dried and used for the next reaction.

[0029]

embedded image Synthesis of Compound (7) 50 g of 4-benzyloxybenzonitrile was dissolved in dry ethanol and cooled. Hydrogen chloride gas was blown into the mixture, and the mixture was stirred at room temperature for 2 days. After concentrating the reaction solution under reduced pressure,
It was dissolved in methanol, ammonia gas was blown into it, and the mixture was stirred for one day. The solvent was distilled off from the reaction solution under reduced pressure, and the amidine salt (
7) was obtained.

[0030]

embedded image Synthesis of Compound (8) Compound (6) and 41 g of the amidine salt (7) obtained in [4] were dissolved in methanol. Sodium methoxide 85g
was added and refluxed for 2 hours. Insoluble materials were removed from the reaction solution while hot, and the mixture was concentrated. The concentrated solution was dissolved in ethyl acetate, and hydrogenated using palladium carbon as a catalyst. The reaction solution was concentrated, and the residue was recrystallized from a mixed solvent of hexane and toluene.
A phenol compound (8) was obtained. Yield 285g (26% yield from 4-benzyloxybenzaldehyde)

003
1] [6] Synthesis of diene compound (C) Diene compound (B
) 30 mmol of ether (1) obtained by the synthesis of [
5) A solution of 30 mmol of the phenol compound (8) obtained in step 5] and 0.1 mol of potassium carbonate in 150 ml of acetone was added to
Refluxed for an hour. After filtering and concentrating the reaction solution, the target diene compound (C) is purified by column chromatography.
I got it. (Yield 42%) This diene compound exhibits liquid crystallinity and exhibits the following phase transition behavior.

Response time: 115μs (59°C), 815μs (39°C
) Tilt angle (2θ): 88° (39°C)

Synthesis of compound (D)

embedded image 40 g of 4-methoxybenzonitrile was dissolved in ethanol and cooled. Blow dry hydrogen chloride gas into it,
Stirred at room temperature for 2 days. After the reaction solution was concentrated under reduced pressure, it was dissolved in methanol, ammonia gas was blown into the solution, and the solution was stirred for one day. The solvent was distilled off from the reaction solution under reduced pressure to obtain amidine salt (9).

[0034]

Synthesis of Compound (10) 50 g of the above amidine salt, 2-ethoxycarbonyl-3-dimethylaminoacrolein, were mixed in ethanol,
45 g of sodium ethoxide was added little by little to this, and the mixture was refluxed for 2 hours. Insoluble materials were removed from the reaction mixture by filtration while hot, and the mixture was allowed to cool, and the resulting precipitate (10) was collected.

[0035]

Synthesis of Compound (11) After deprotecting (10) obtained above by HBr/acetic acid treatment, it was heated and stirred in acetic anhydride at 120°C for 1 hour to acetylate (11). ) was obtained.

[0036]

embedded image Synthesis of Compound (12) The above-obtained (11) was dried under reduced pressure, refluxed in thionyl chloride, and concentrated to give an acid chloride. The acid chloride compound was dissolved in toluene, and (S)-2-
A toluene solution containing 15 g of pentanol and 20 g of pyridine was added dropwise. The mixture was stirred at room temperature for 1 day. Insoluble materials were removed from the reaction solution by filtration, and the mixture was concentrated under reduced pressure. The residue was dissolved in ether, 35 g of benzylamine was added, and the mixture was stirred at room temperature for 3 hours. The reaction solution was washed with dilute hydrochloric acid, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by column chromatography to obtain a phenol compound (12). Yield 283g (33% yield from 4-methoxybenzonitrile)

Synthesis of diene compound (D) Diene compound (D)
Synthesis of B) 30 mmol of the ether (1) obtained in [1], 30 mmol of the phenol (12) obtained in [4], and 150 ml of acetone containing 0.1 mole of potassium carbonate.
The solution is refluxed for 12 hours. The reaction solution was filtered and concentrated, and then purified by column chromatography to obtain the desired diene compound (D). (Yield 39%) This diene compound exhibits liquid crystallinity and exhibits the following phase transition behavior and physical property values.

[0038] Response time: 210μs (21℃) Tilt angle (2θ): 56° (21°C)

Synthesis of diene compound (E)

embedded image 0.1 mol of 1,5-hexadien-3-ol and 0.17 mol of sodium hydride are stirred in 150 ml of THF at room temperature for 1 hour. Next, 0.3 mol of 1,12-dibromododecane is introduced and the mixture is refluxed for 12 hours. The reaction solution was filtered and concentrated, and then purified by column chromatography to obtain the desired ether (13). (yield 55%)

00
40]

[Chemical formula 28] 60 mmol of the ether (13) obtained in [1], 4
- 150 ml of acetone solution of 60 mmol of hydroxybenzoic acid methyl ester and 0.2 mol of potassium carbonate
It was refluxed for 2 hours. After filtering and concentrating the reaction solution, the desired ether form (14) was purified by column chromatography.
I got it.

[0041]

[Chemical formula 29] 30 mmol of the ester (14) obtained in [2], 0.1 mol of sodium hydroxide, 50 ml of ethanol, 2 ml of water
Reflux the 0 ml solution for 30 minutes. The reaction solution was poured into 500 ml of water, the pH was adjusted to 2 with dilute HCl water, the reaction solution was extracted with ether, dried, concentrated, and purified by column chromatography to obtain the desired carboxylic acid derivative (15). Obtained. (Yield 96%)

20 ml of thionyl chloride is introduced into 50 mmol of the carboxylic acid derivative (15) obtained in the synthesis of diene compound (E) [3], and the mixture is stirred at 80° C. for 3 hours. Excess thionyl chloride is distilled off from the reaction solution under reduced pressure to obtain an acid chloride. Next, a THF 150 ml solution of 50 mmol of the phenol compound (12) obtained in synthesis [4] of the diene compound (D) and 60 ml of triethylamine was stirred, and the THF solution of the acid chloride obtained earlier was added dropwise to the solution for 12 hours. Stir. The reaction solution was extracted with ether, dried, concentrated, and purified by column chromatography to obtain the desired diene compound (E
) was obtained. (Yield 41%) This diene compound exhibits liquid crystallinity and exhibits the following phase transition behavior and physical property values.

[0043] Response time: 106μs (32℃) Tilt angle (2θ): 43° (32°C)

Synthesis of optically active low molecular weight non-liquid crystal compound (d)

embedded image Add 60% by weight of oily NaH to 4 ml of DMF. followed by 2-(4-hydroxyphenyl)-5-((S)-1
-Methylbutoxy)pyrimidine (2.07 g) in DMF is added and stirred at room temperature for 15 minutes. After confirming that the generation of hydrogen gas has stopped, dodecyl bromide 2.99
4 ml of DMF solution is added dropwise. After stirring for 8 hours at room temperature, the reaction mixture is poured into 100 ml of water. Add dilute hydrochloric acid to make acidic and extract with methylene chloride. The organic layer is dried over magnesium sulfate and the solvent is removed on a rotary evaporator. By purifying the residue by column chromatography, the desired low molecular non-liquid crystal compound 2.8
7g was obtained. (yield 84%)

The phase transition temperatures (°C) of the low molecular weight liquid crystal compounds (a) to (e) are shown below. (E) SmIA* - SmCA* - Sm
Cr* − SmC* − SmCr* −
SmA-Iso6
4 118.4 119.2 1
20.9 122 148

004
6] None of them show SmC* phase at 25℃, so 25℃
There is no data. Note that SmIA* represents an antiferrochiral smectic I liquid crystal phase, SmCA* represents an antiferrochiral smectic C liquid crystal phase, and SmCr* represents a chiral smectic Cr phase.

Example 1 A ferroelectric liquid crystal composition containing 65% by weight of (A) was prepared from a diene compound (A) and a non-optically active SmC low-molecular liquid crystal compound (a) by the following method. . That is, 0.65 g of the diene compound (A) and 0.35 g of the non-optically active SmC low-molecular liquid crystal compound (A) were dissolved in 10 ml of dichloromethane to form a uniform solution. The desired ferroelectric liquid crystal composition was prepared by distilling off the solvent using a rotary evaporator and then drying using a vacuum pump to completely remove the solvent. The phase transition behavior of this liquid crystal composition during the cooling process was determined by observation with a polarizing microscope, and the results were as shown below.

[0048] In the SmC* phase temperature range, no disturbance in orientation due to phase separation was observed under a microscope. In addition, when the response time of this liquid crystal composition to an electric field was measured, it was found that the response time was 25°C.
The time was 50 μs.

However, the measurements were carried out as follows. That is, a liquid crystal composition was sandwiched between two ITO glass substrates, and an alignment cell with a thickness of 2 μm was produced by a shearing method. Further, an electric field of ±10 MV/m was applied under crossed Nicol conditions, and the time required for the amount of change in light transmittance to reach 10 to 90% was measured. Furthermore, the tilt angle (2θ) at 25℃
When measured, it was 41°.

Examples 2 to 8 Liquid crystal compositions having the compositions shown in Table 1 were prepared in the same manner as in Example 1, and phase transition behavior was observed and response time was measured under the same conditions as in Example 1. , the tilt angle was measured. The results are shown in Table 1.

In any of the liquid crystal compositions of Examples,
No disturbance in orientation due to phase separation within the SmC* phase temperature range was observed under the microscope.

[0052]

[Table 1]

[0053]

[Effects of the Invention] The liquid crystal composition of the present invention exhibits a high-speed electric field response at room temperature, is less likely to cause phase separation, and has the advantages of being able to easily control the transition temperature and tilt angle by adjusting the composition. have. That is, according to the present invention, it is possible to provide a practically excellent liquid crystal composition that exhibits the above-mentioned extremely excellent liquid crystal properties.

Claims (1)

[Claims] Claim 1: A diene compound represented by the following general formula [
[Formula, r and p are integers of 2 to 5, and R1 is [Formula 2]. However, R2 is -COOR3, -OR3 or -
OCOR3, R3 is [Image Omitted], R4 and R5 are -CH3 or a halogen atom, a and d are integers of 0 to 10, and b is 0 or 1. (When R5 is -CH3, d is not 0.)
] and a low molecular weight liquid crystal compound.