JP2537470B2 - Liquid crystal device using liquid crystal composition containing fluoroalkane derivative - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device using a novel liquid crystalline compound, and more specifically to a liquid crystal composition containing the liquid crystalline compound which is an optically active fluoroalkane derivative and the liquid crystal. The present invention relates to a liquid crystal device using the composition.

[0002]

2. Description of the Related Art As a conventional liquid crystal element, for example,
"Applied Physics" by M. Schadt and W. Helfrich
s Letters ") Volume 18, Issue 4 (Published February 15, 1971), pages 127-128," Voltage Dependant Optical Activity of a Twisted Nematic Liquid Crystal ". ("Voltage Dependent
Optical Activity of a Twi
Sted Nematic Liquid Crystal
al ”) shown in Twisted nematic (twi
A liquid crystal device using a liquid crystal is known. This TN liquid crystal has a problem that crosstalk occurs during time-division driving using a matrix electrode structure having a high pixel density, and thus the number of pixels is limited.

Further, since the electric field response is slow and the viewing angle characteristic is poor, its use as a display is limited.

Further, a display element of a type in which a switching element made of a thin film transistor is connected to each pixel and each pixel is switched is known, but the step of forming the thin film transistor on the substrate is extremely complicated and a large area is required. There is a problem that it is difficult to create a display element.

As an amelioration of the drawbacks of the conventional liquid crystal device, the use of a liquid crystal device having bistability is disclosed by Clark and Lagerw.
all) (JP-A-56-1072).
16 publication, US Pat. No. 4,367,924, etc.).
As the liquid crystal having bistability, a ferroelectric liquid crystal having a chiral smectic C phase (SmC ^* ) or H phase (SmH ^* ) is generally used.

Since this ferroelectric liquid crystal has a very fast response speed because it has spontaneous polarization, it can express a bistable state having a memory property, and further has excellent viewing angle characteristics. Suitable as a large-capacity, large-screen display material.

Since the material used as the ferroelectric liquid crystal has asymmetry, it is used not only as the ferroelectric liquid crystal utilizing the chiral smectic phase but also as the following optical element. be able to.

1) Utilizing the cholesteric / nematic phase transition effect in the liquid crystal state (JJ Wys)
oki, A .; Adams and W.D. Haas; Ph
ys. Rev. Lett. , 20, 1024 (196
8)), 2) A liquid crystal state that utilizes the white Taylor type guest-host effect (DL White and and
G. N. Taylor; Appl. Phys. ,
45 , 4718 (1974)), etc. are known. Although detailed description of each method is omitted, it is important as a display element or a modulation element.

In such a method using the electric field response optical effect of liquid crystal, it is said that it is preferable to introduce a polar group in order to enhance the response of the liquid crystal. In particular, it is known that the response speed of a ferroelectric liquid crystal is proportional to the spontaneous polarization, and it is desired to increase the spontaneous polarization for speeding up. From this point, P. Keller
Et al. Have shown that a chlorine group can be directly introduced into an asymmetric carbon to increase spontaneous polarization and increase the response speed (CR Acad. Sc. Paris, 282 C, 6).
39 (1976)). However, the chlorine group introduced into the asymmetric carbon is chemically unstable and has a drawback that the stability of the liquid crystal phase is deteriorated due to its large atomic radius, and improvement thereof is desired. There is.

On the other hand, a functional material required for an optical element characterized by having optical activity is often synthesized through an optically active intermediate, but as an optically active intermediate conventionally used. Is 2-methylbutanol, 2
Octyl alcohol, secondary butyl alcohol, chloride p
Only-(2-methylbutyl) benzoic acid, a secondary phenethyl alcohol, an amino acid derivative, a camphor derivative, a cholesterol derivative, etc. were mentioned, and a polar group was hardly introduced into this optically active intermediate. For this reason, the method of increasing spontaneous polarization by directly introducing a polar group into an asymmetric carbon atom has not been used very effectively.

[0011]

The present invention has been made in view of the above points. That is, the present invention is a liquid crystal composition containing at least one liquid crystalline compound in which a stable fluorine atom having a large dipole moment is directly introduced into an asymmetric carbon atom to enhance the polarity and enhance the electric field response of the liquid crystal. An object is to provide a liquid crystal element using an object.

[0012]

The present invention has been made to achieve the above-mentioned object, and has the general formula (I)

[0013]

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(Here, R ₁ is an alkyl group having 4 to 16 carbon atoms having an asymmetric carbon atom, and R ₂ is 1 to 1 carbon atoms.
6 represents an alkyl group, and C ^* represents an asymmetric carbon atom. )
A liquid crystal device comprising a liquid crystal composition containing at least one kind of a fluoroalkane derivative represented by the formula (1) held between a pair of electrode substrates.

DETAILED DESCRIPTION OF THE INVENTION The fluoroalkane derivative represented by the above general formula (I) is preferably an optical one such as 2-fluoro-1-alkanol described in the specification of Japanese Patent Application No. 60-232886. Synthesized from active intermediates.

For example, the fluoroalkane derivative represented by the general formula (I) can be obtained from these optically active intermediates by the following synthetic route.

[0017]

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(Here, R ₁ , R ₂ and C ^* are as defined above.) The liquid crystal composition used in the present invention contains at least the fluoroalkane derivative represented by the above general formula (I). It is contained as one kind of blending component. For example, when this fluoroalkane derivative is combined with a ferroelectric liquid crystal represented by the following formulas (1) to (13), the spontaneous polarization is increased and the response speed can be improved.

In such a case, the general formula (I)
It is preferable to use the fluoroalkane derivative represented by the following in an amount of 0.1 to 99% by weight, particularly 1 to 90% by weight of the obtained liquid crystal composition.

[0020]

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[0021]

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[0022]

[Chemical 6]

[0023]

[Chemical 7]

[0024]

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Further, by blending with a smectic liquid crystal which is not chiral itself as shown in the following formulas 1) to 5), a composition usable as a ferroelectric liquid crystal can be obtained.

In this case, the fluoroalkane derivative represented by the general formula (I) is used in an amount of 0.1 to 9 of the resulting liquid crystal composition.
It is preferable to use 9% by weight, particularly 1 to 90% by weight.

Such a composition can obtain a large spontaneous polarization due to the content of the fluoroalkane derivative represented by the general formula (I).

[0028]

[Chemical 9]

[0029]

[Chemical 10]

Further, the fluoroalkane derivative represented by the general formula (I) is effective in preventing generation of a reverse domain in a TN type cell when added to a nematic liquid crystal. In this case, it is preferable to use the fluoroalkane derivative of the formula (I) in an amount of 0.01 to 50% by weight of the obtained liquid crystal composition.

When added to nematic liquid crystal or chiral nematic liquid crystal, it can be used as a chiral nematic liquid crystal in a phase transition type liquid crystal device or a white Taylor type guest-host liquid crystal device as a liquid crystal composition. In this case, 0.
It is preferable to use the fluoroalkane derivative of the formula (I) in a proportion of 01 to 80% by weight.

The present invention will be described in more detail with reference to compound preparation examples and examples.

Compound Production Example 1

[0034]

[Chemical 11]

5- (4-methylhexyl) -2- [4- (2-fluorooctyloxy) represented by the above formula
Phenyl] pyrimidine was prepared by the following steps.

[0036]

[Chemical 12]

(1) Synthesis of 2-fluorooctyl-p-toluenesulfonic acid ester.

2-fluoro-n-octanol 10 g
(67.6 mmol) was dissolved in 20 ml of pyridine, and 0
P-toluenesulfonic acid chloride under cooling to 15.degree.
5 g (81.1 mmol) of pyridine solution was added dropwise and 0
The reaction was carried out at a temperature of 5 ° C to 5 ° C for 1 hour, and further at 15 ° C to 20 ° C for 7 hours. Then, the reaction solution was poured into 200 ml of ice water, then acidified with a 2N HCl aqueous solution, further extracted with methylene chloride, the extracted layer was washed with water, and after confirming that the aqueous layer was neutral, sulfuric acid was added. It was dried using magnesium and the solvent was distilled off. Furthermore, purification was performed using silica gel column chromatography to obtain 2-fluorooctyl-p-toluenesulfonic acid ester 13.0.
g was obtained.

(2) Synthesis of p- (2-fluorooctyloxy) cyanobenzene.

P-Toluenesulfonic acid (2-fluoro
Octyl) 2.85 g (9.44 mmol) and p-cyano
1.15 g (9.44 mmol) of phenol was added to n-butane.
Dissolve in 4 ml of knoll, sodium hydroxide 0.477
g (11.3 mmol) was added and the mixture was refluxed at 120 ° C. for 5 hours.
Was. After completion of the reaction, extract with ether and perform column chromatography.
By Raffy (dichloromethane: benzene = 4: 1)
p- (2-fluorooctyloxy) cyanobenzene 2.
22 g (8.92 mmol) was obtained. Yield 94%. [Α]_D ^26.8 -2.40 ° (C = 0.916, Ben
Zen) [α] ₄₃₅ ^26.8-8.52 ° (〃, 〃
 )

(3) Synthesis of p- (2-fluorooctyloxy) benzamidine hydrochloride.

P-in 13 ml of dry ethanol in a freezing agent
(2-Fluorooctyloxy) cyanobenzene 2.6
Hydrogen chloride was blown into the solution to which 6 g (10.7 mmol) had been added until it was saturated, and the mixture was stirred at room temperature for 24 hours. After the reaction, the solvent was distilled off, the residue was dried over phosphorus pentoxide and potassium hydroxide, and then 10 ml of dry ethanol was added. Ammonia was blown into 20 ml of dry ethanol in advance to saturate the obtained solution, and the solution was quickly poured into the prepared solution and stirred at room temperature for 2 nights. Then, the solvent was distilled off, the residue was filtered with ether, and recrystallized with 23 ml of 6N hydrochloric acid to obtain 2.57 g (8.50 mmol) of p- (2-fluorooctyloxy) benzamidine hydrochloride. 79% yield. m. p. 150 ° C-182 ° C.

(4) 4,6-dihydroxy-5- (4-
Synthesis of methylhexyl) -2- [4- (2-fluorooctyloxy) phenyl] pyrimidine.

7 ml of dry methanol was mixed with 0.
After adding 29 g (12.6 ml) and completely dissolving,
1.29 g (4.2 mmol) of p- (2-fluorooctyloxy) benzamidine hydrochloride and 1.08 g (4.2 mmo of diethyl 2- (4-methylhexylmalonate).
l) was added, the mixture was refluxed at 80 ° C. for 8 hours, and further at room temperature for 14
Stirred for hours. After completion of the reaction, 2N-hydrochloric acid was added, filtered, washed with water and ethanol, and then dried at 120 ° C. for 1 hour. After that, recrystallization was carried out with 5 ml of DMF and 4,6-dihydroxy-5- (4-methylhexyl) -2- [4-
1.21 g (2.93 mmol) of (2-fluorooctyloxy) phenyl] pyrimidine was obtained. Yield 70%.

(5) Synthesis of 4,6-dichloro-5- (4-methylhexyl) -2- [4- (2-fluorooctyloxy) phenyl] pyrimidine.

4,6-dihydroxy-5- (4-methyl)
Hexyl) -2- [4- (2-fluorooctyloxy)
Si) phenyl] pyrimidine 1.20 g (2.9 mmo
l), 1 ml of N, N-diethylaniline and phosphochloride
6 ml of ril was added and the mixture was refluxed at 110 ° C. for 47 hours. reaction
After completion, distill off excess phosphoryl chloride and remove sodium hydroxide.
Solution was added and extraction was performed with ether. Extract 1
Column chromatograph after sequentially washing with N-hydrochloric acid and water
(Benzene: hexane = 1: 2)
Chloro-5- (4-methylhexyl) -2- [4- (2
-Fluorooctyloxy) phenyl] pyrimidine 1.
08 g (2.4 mmol) was obtained. Yield 83%. [Α]_D ^25.6  -1.09 ° (C = 0.920, Ben
Zen) [α]₄₃₅ ^26.4-5.00 ° (〃,
〃)

(6) 5- (4-methylhexyl) 2-
Synthesis of [4- (2-fluorooctyloxy) phenyl] pyrimidine.

To 10 ml of ethanol and 0.6 ml of water,
4,6-dichloro-5- (4-methylhexyl) -2-
[4- (2-Fluorooctyloxy) phenyl] pyrimidine 0.95 g (2.1 mmol), 5% -palladium activated carbon 200 mg, magnesium oxide 0.32 g
(8.0 mmol) was added, and hydrogen substitution was carried out using an atmospheric pressure hydrogenation device. After the reaction, by column chromatography (benzene), 5- (4-methylhexyl) -2-
0.41 g (1.08 mmol) of [4- (2-fluorooctyloxy) phenyl] pyrimidine was obtained. Yield 5
1%. [Α] _D ^26.8 + 5.83 ° (C = 0.824, Et
₂ O) [α] ₄₃₅ ^26.8 + 18.0 ° (C = 0.824, Et
₂ O)

Compound Production Examples 2-3 : 2-fluoro-1-alkanol which gives R ₁ and R ₂ shown in Table 1 in place of 2-fluorooctanol and diethyl 4-methylhexylmalonate used in Compound Production Example 1, Further, fluoroalkane derivatives shown in Table 1 were obtained in the same manner as in Compound Production Example 1 except that and the malonic acid diethyl derivative was used.

The specific optical rotation and the phase transition temperature of the product are shown in Table 1 together with those of Compound Preparation Example 1.

[0051]

[Table 1]

Example 1 Compound The following liquid crystal composition containing the fluoroalkane derivative produced in Production Examples 1 and 3 as a component was prepared.

[0053]

[Chemical 13]

It was found that this liquid crystal composition had a SmC ^* phase at 5.4 to 44.3 ° C. and had a large spontaneous polarization of 8.0 nC / cm ² at 25 ° C. Then, the above liquid crystal composition was sandwiched between a pair of electrode substrates obtained by subjecting the polyimide coating covering the electrodes to a rubbing treatment to prepare an element having a liquid crystal layer thickness of 2 μm. When driven at 25 ° C. with a drive voltage of ± 15 V and a pulse width of 300 μsec, a good switching state with a contrast of 17 was obtained.

Example 2 ITO (Indium Tin Oxi) was used as a transparent electrode.
de) A polyimide resin precursor [SP-510 manufactured by Toray Industries, Inc.] was used to form a film on the glass substrate on which the film was formed by spinner coating, and then baked at 300 ° C. for 60 minutes to form a polyimide film. Next, this coating was subjected to orientation treatment by rubbing to make cells so that the rubbing treatment axes were orthogonal to each other (cell spacing 8 μm). A nematic liquid crystal composition [Rixon GR-63: biphenyl liquid crystal mixture manufactured by Chisso Corporation] was injected into the above cell to form a TN (twisted nematic) type cell, which was observed with a polarization microscope to find that the reverse domain (stripe pattern ) Has occurred.

Using a liquid crystal mixture obtained by adding the fluoroalkane derivative (1 part by weight) of the above-mentioned Compound Production Example 2 to the above-mentioned Rixon GR-63 (99 parts by weight), and observing a TN cell in the same manner as above No reverse domain was observed, and the nematic phase had good uniformity. From this, it was found that the fluoroalkane derivative is effective in preventing the reverse domain.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Goji Kadano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Ichiharu Katagiri 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (1)

(57) [Claims] 1. A compound represented by the following general formula (I) (Here, R ₁ has 4 to 16 carbon atoms having an asymmetric carbon atom.
R ₂ is an alkyl group having 1 to 16 carbon atoms, and C ^* is an asymmetric carbon atom. (3) A liquid crystal device comprising a liquid crystal composition containing at least one fluoroalkane derivative represented by the formula (1) held between a pair of electrode substrates.