JPH0657677B2 - Liquid crystalline compound and liquid crystal composition containing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel liquid crystal compound, a liquid crystal composition containing the same, and a liquid crystal device using the liquid crystal composition. More specifically, the present invention relates to an optically active fluoroalkane derivative. The present invention relates to a liquid crystal compound, a liquid crystal composition containing the liquid crystal compound, and a liquid crystal device using the liquid crystal composition.

Background Art As a conventional liquid crystal element, for example, M-shut (MS
chadt) and W. Helfrich
By "Applied Physics Letters"("Applie
d Physics Letters "), Vol. 18, No. 4, (Published February 15, 1971), pages 127-128," Voltage Dependent Ophthalmic Activity of a Twisted Nematic Liquid. " Crystal ”(“ Voltage Dependent Optical Activity
of a Twisted Nematic Liquid Crystal ”)
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, the use as a display has been limited because the electric field response is slow and the viewing angle characteristics are poor.

In addition, a display element of a type in which a switching element using a thin film transistor is connected to each pixel and switching is performed for each pixel is known, but a step of forming a thin film transistor on a substrate is extremely complicated, and a large area display element is used. There are problems that are difficult to create.

The use of a bistable liquid crystal element has been proposed as a solution to the drawbacks of the conventional type liquid crystal element.
rk) and Lagerwall (JP-A-56-107216, US Pat. No. 43).
67924, etc.). As a liquid crystal having bistability, a chiral smectic C phase (SmC ^* ) is generally used.
Alternatively, a ferroelectric liquid crystal having an H phase (SmH ^* ) is used.

This ferroelectric liquid crystal has a very fast response speed due to its spontaneous polarization, and can express a bistable state with a memory property. Moreover, it has a large viewing angle characteristic and thus has a large capacity and a large capacity. Suitable as a display material for screens.

Further, since the material used as the ferroelectric liquid crystal has asymmetry, it can be used not only as the ferroelectric liquid crystal utilizing the chiral smectic phase but also as the following optical element. .

1) Utilizing the cholesteric / nematic phase transition effect in the liquid crystal state (JJWysoki, A. Adams and WH
aas; Phys.Rev.Lett., 20,1024 (1968)), 2) Utilizing the white Taylor type guest-host effect in the liquid crystal state (DL. White and GNTaylo)
r; J. Appl. Phys. , 45 , 4718 (1974), etc. are known. A detailed explanation of each method is omitted,
It is important as a display element and 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. Especially in ferroelectric liquid crystals, it is known that the response speed is proportional to the spontaneous polarization,
It is desired to increase the spontaneous polarization for speeding up. From this point of view, P.Keller et al. Showed that by introducing a chlorine group directly into the asymmetric carbon, the spontaneous polarization can be increased and the response speed can be increased (CRAcad.Sc.Par.
is, 282 C, 639 (1976)). However, the chlorine group introduced into the asymmetric carbon is chemically unstable and
Since it has a large atomic radius, it has a drawback that the stability of the liquid crystal phase is lowered, and its improvement is desired.

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 itself, but as an optically active intermediate used conventionally, 2 -Methylbutanol, secondary octyl alcohol, secondary butyl alcohol, p- (2-methylbutyl) benzoic acid chloride, secondary phenethyl alcohol, amino acid derivatives, camphor derivatives, cholesterol derivatives, etc. Almost no polar group was introduced into. For this reason, the method of increasing spontaneous polarization by directly introducing a polar group into an asymmetric carbon atom has not been effectively used.

OBJECT OF THE INVENTION The present invention has been made in view of the above points. That is, the present invention provides a liquid crystal compound in which a polar group is enhanced by directly introducing a stable and large dipole moment fluorine group into an asymmetric carbon atom, and a liquid crystal compound in which at least one kind of the liquid crystal compound is contained. It is intended to provide a composition.

In the present invention, it is easy to change the length of the alkyl group, which allows H. Arnold, Z. Phys. Chem., 226, 146 (1964)
It is an object of the present invention to provide a liquid crystal compound capable of controlling the type and temperature range of a liquid crystal phase that develops in a liquid crystal state as shown in, and a liquid crystal composition containing at least one compounding component thereof.

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and has the general formula (I) (Here, R ₁ is an alkoxy group having 9 to 16 carbon atoms,
₂ represents an alkyl group having 1 to 16 carbon atoms. C ^* represents an asymmetric carbon atom. The present invention provides a fluoroalkane derivative represented by

The present invention also provides a liquid crystal composition containing at least one kind of the fluoroalkane derivative as a compounding component, and a liquid crystal device using the liquid crystal composition.

DETAILED DESCRIPTION OF THE INVENTION The optically active fluoroalkane derivative represented by the above general formula (I) is preferably 2- as shown in the specifications of Japanese Patent Application Nos. 60-232886 and 61-40793.
Fluoro-1-alkanol, p-hydroxybenzoic acid (2-fluoroalkyl) ester, p-hydroxybiphenylcarboxylic acid (2-fluoroalkyl) ester, hydroquinone (2-fluoroalkyl) ether, 4- [4 ′-(2 Synthesized from an optically active intermediate such as -fluoroalkyl) oxyphenyl] phenol.

For example, a liquid crystal compound represented by the general formula (I) can be obtained from these optically active intermediates by the following synthetic route.

Hereinafter, examples of the fluoroalkane derivative represented by the general formula (I) thus synthesized will be shown.

p-nonyloxybenzoate-p '-(2-fluorodecyloxycarbonyl) phenyl, p-decyloxybenzoate-p'-(2-fluorodecyloxycarbonyl) phenyl, p-dodecyloxybenzoate-p '-(2 -Fluorodecyloxycarbonyl) phenyl, p-tetradecyloxybenzoic acid-p '-(2-fluorodecyloxycarbonyl) phenyl, p-hexadecyloxybenzoic acid-p'-(2-fluorodecyloxycarbonyl) phenyl, p-decyloxybenzoate-p '-(2-fluorobutyloxycarbonyl) phenyl, p-decyloxybenzoate-p'-(2-fluorohebutyloxycarbonyl) phenyl, p-decyloxybenzoate-P '-(2 -Fluorononyloxycarbonyl) phenyl, p- Decyloxybenzoic acid-p '-(2-fluorodotecyloxycarbonyl) phenyl, p-dodecyloxybenzoic acid-p'-(2-fluorotetradecyloxycarbonyl) phenyl, p-hexadecyloxybenzoic acid-p'- (2-Fluorooctadecyloxycarbonyl) phenyl.

The liquid crystal composition of the present invention contains at least one fluoroalkane derivative represented by the general formula (I) as a 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 fluoroalkane derivative of the present invention represented by the general formula (I) is used in an amount of 0.1 to 99% by weight, particularly 1 to 90% by weight of the obtained liquid crystal composition. Is preferred.

Further, by compounding 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, it is preferable to use the liquid crystal compound of the present invention represented by the general formula (I) in an amount of 0.1 to 99% by weight, particularly 1 to 90% by weight of the obtained liquid crystal composition.

Such a composition can obtain a large spontaneous polarization due to the content of the liquid crystal compound of the present invention.

Here, the symbols indicate the following phases, respectively.

Cryst. : Crystal phase, SmA: Smectic A phase, SmB: Smectic B phase, SmC: Smectic C phase, N: Nematic phase, Iso .: Isotropic phase.

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

Also, by adding to nematic liquid crystal or chiral nematic liquid crystal, as chiral nematic liquid crystal,
It can be used as a liquid crystal composition in a phase transition type liquid crystal device or a white Taylor type guest-host liquid crystal device. In this case, it is preferable to use the liquid crystal compound of the formula (I) so that the ratio is 0.01 to 80% by weight of the obtained liquid crystal composition.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 By the reaction steps shown in the following (1), (2) and (3), p-tridecyloxybenzoic acid-p '-(2-fluorooctyloxycarbonyl) phenyl ester of the above formula was produced.

(1) Production of p-acetyloxybenzoic acid-2-fluorooctyl ester.

7.4 g of p-acetyloxybenzoic acid (4.11 x 10)
^-2 mol), thionyl chloride (30 ml) was added and the mixture was heated under reflux for 5 hours and 30 minutes, and then excess thionyl chloride was distilled off under reduced pressure.
-Acetyloxybenzoyl chloride was obtained.

2-fluorooctanol 6.0 g (4.05 × 10 ^-2
mol) was dissolved in 20 ml of pyridine and 20 ml of toluene. P-acetyloxybenzoic acid chloride was added to this,
The mixture was added dropwise at 5 ° C or lower over 50 minutes. After stirring for 12 hours at room temperature, the reaction solution was poured into 200 ml of ice water. After adding a 6N hydrochloric acid aqueous solution to make it acidic, the mixture was extracted with ethyl acetate. The organic phase was washed with water, 5% sodium hydrogen carbonate solution, water and then dried over magnesium sulfate. After the solvent was distilled off, the residue was purified by column chromatography (silica gel-hexane / ethyl acetate = 10/1) to obtain 9.83 g of a colorless transparent liquid. (Yield 78.3%) (2) Production of p-hydroxybenzoic acid-2-fluorooctyl ester.

P-Acetyloxybenzoic acid-2-obtained in (1) above
Fluorooctyl ester 9.6g (3.09 × 10 ^-2
(mol) was dissolved in 32 ml of isopropyl ether, 2.3 g (3.09 × 10 ^-2 mol) of butylamine was added thereto, and the mixture was left at room temperature overnight.

After washing with water, the solvent was distilled off, and the residue was purified by column chromatography (silica gel-methylene chloride / ethyl acetate = 9/1) to obtain 7.75 g of a pale yellow transparent liquid. (Yield 94.
2%) (3) Production of p-tridecyloxybenzoic acid-p '-(2-fluorooctyloxycarbonyl) phenyl ester.

1.6 g of p-tridecyloxybenzoic acid (4.93 × 1)
0 ^-3 mol) in thionyl chloride 5ml was added and heated to reflux for 5 hours 30 minutes, then evaporated under reduced pressure and excess thionyl chloride, p-
Tridecyloxybenzoic acid chloride was obtained.

1.04 g (3.88 × 10 ⁻³ ) of p-hydroxybenzoic acid-2-fluorooctyl ester obtained in the above (2)
mol) was dissolved in 4 ml of pyridine and 8 ml of toluene. To this, p-tridecyloxybenzoic acid chloride was added dropwise at 5 ° C or lower over 10 minutes. After stirring for 13 hours at room temperature, the reaction solution was poured into 100 ml of ice water. The mixture was acidified with a 6N aqueous hydrochloric acid solution and extracted with ethyl acetate. The organic layer was washed successively with water, 5% sodium hydrogen carbonate and water, and then dried over magnesium sulfate. After evaporation of the solvent,
Purification by column chromatography (silica gel-benzene) and recrystallization from ethanol gave 1.3 g of p-tridecyloxybenzoic acid-p '-(2-fluorooctyloxycarbonyl) phenyl ester.
(Yield 59.3%) The product showed the following phase transition temperature (° C).

S ₃ : Not identified.

Examples 2 to 4 The same as Example 1 except that p-nonyloxybenzoic acid, p-decyloxybenzoic acid, and p-dodecyloxybenzoic acid were used instead of p-tridecyloxybenzoic acid. Then, the fluoroalkane derivative of the present invention shown in Table 1 below was obtained.

The phase transition temperatures of the products are shown in Table 1 below.

Example 5 The following liquid crystal composition A containing the compound produced in Example 4 as a blending component was prepared. As a comparative example, a liquid crystal composition B containing no compound of Example 4 was also prepared. The phase transition temperature and spontaneous polarization of each of the liquid crystal compositions A and B are shown below.

<Liquid crystal composition A> <Liquid crystal composition B> Next, prepare two 0.7 mm thick glass plates, form an ITO film on each glass plate, and create a voltage application electrode.
Further, SiO ₂ was vapor-deposited on this to form an insulating layer. Silane coupling agent on glass plate [KB manufactured by Shin-Etsu Chemical Co., Ltd.
M-602] 0.2% isopropyl alcohol solution was applied with a spinner at a rotation speed of 2000 rpm for 15 seconds,
The surface was treated. Then, it was dried by heating at 120 ° C. for 20 minutes.

Polyimide resin precursor [Toray Industries, Inc. SP-510] 2% on a glass plate with ITO film which was further surface treated
The dimethylacetamide solution was applied for 15 seconds using a spinner having a rotation speed of 2000 rpm. 30 minutes after film formation for 30 minutes
A 0 ° C. heat condensation baking treatment was performed. At this time, the film thickness of the coating film was about 700Å.

The coating after the baking is rubbed with an acetate flocked cloth, then washed with an isopropyl alcohol solution, and sprayed on one glass plate with alumina beads having an average particle diameter of 2 μm. Put the glass plates parallel to each other, and glue the glass plates together using an adhesive sealant [Rixon Bond (Chisso Corporation)], and
A cell was prepared by heating and drying at 100 ° C. for 0 minutes. When the cell thickness of this cell was measured with a Berek phase plate,
It was about 2 μm. Here, each of the ferroelectric liquid crystal compounds A and B prepared above was vacuum-injected into the prepared cell in an isotropic phase in a homogeneous mixed liquid state. A ferroelectric liquid crystal device was prepared by gradually cooling from the isotropic phase at 0.5 ° C./h.

Using this ferroelectric liquid crystal device, an optical response (transmission light amount change of 0 to 90%) was detected by applying a peak-to-peak voltage of 30 V to measure the response speed. The results are shown below.

Example 6 A polyimide resin precursor [SP manufactured by Toray Industries, Inc.] was formed on a glass substrate on which an ITO (Indium Tin Oxide) film was formed as a transparent electrode.
-510] to form a film by spinner coating, and then 3
A polyimide film was obtained by baking at 00 ° C. for 60 minutes. Then, this coating film 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). Nematic liquid crystal composition [Rixon G
R-63: Biphenyl liquid crystal mixture manufactured by Chisso Corp.] is injected to form a TN (twisted nematic) type cell,
Observation with a polarizing microscope revealed that a reverse domain (striped pattern) was generated.

A liquid crystal mixture obtained by adding the liquid crystalline compound (1 part by weight) of Example 2 of the present invention to Rixon GR-63 (99 parts by weight) was used and observed as a TN cell in the same manner as above. No domain was observed and the nematic phase had good uniformity. From this, it was found that the liquid crystal compound of the present invention is effective in preventing the reverse domain.

Front Page Continuation (72) Inventor Kazuharu Kazuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Chieko Hioki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References Japanese Patent Publication No. 5-33943 (JP, B2)

Claims (3)

[Claims] 1. The following general formula (I): (Here, R ₁ is an alkoxy group having 9 to 16 carbon atoms,
₂ represents an alkyl group having 1 to 16 carbon atoms. C ^* represents an asymmetric carbon atom. ) A fluoroalkane derivative represented by: 2. The following general formula (I) (Here, R ₁ is an alkoxy group having 9 to 16 carbon atoms,
₂ represents an alkyl group having 1 to 16 carbon atoms. C ^* represents an asymmetric carbon atom. ) A liquid crystal composition containing at least one kind of a fluoroalkane derivative represented by 3. The following general formula (I) (Here, R ₁ is an alkoxy group having 9 to 16 carbon atoms,
₂ represents an alkyl group having 1 to 16 carbon atoms. C ^* represents an asymmetric carbon atom. ) A liquid crystal device comprising a liquid crystal composition containing at least one fluoroalkane derivative represented by: