JPH0967313A - Carboxylic acid ester compound, antiferroelectric liquid crystal compound, antiferroelectric liquid crystal composition and antiferroelectric liquid crystal device - Google Patents

Abstract

(57) Abstract: Novel carboxylic acid ester compound used as an antiferroelectric liquid crystal compound or a component of an antiferroelectric liquid crystal composition, an antiferroelectric liquid crystal material having a larger tilt angle than ever before And an antiferroelectric liquid crystal element using such an antiferroelectric liquid crystal material having a large tilt angle. An antiferroelectric liquid crystal is prepared by synthesizing a carboxylic acid ester compound in which a hydrogen atom is bonded to two alkyl groups having 3 to 20 carbon atoms and the same carbon number to the central carbon atom of a conventional chiral moiety. A carboxylic acid ester compound exhibiting a phase is obtained. An antiferroelectric liquid crystal composition is prepared by blending the carboxylic acid ester compound thus obtained, and further, an antiferroelectric liquid crystal composition is prepared by using a liquid crystal cell in which these antiferroelectric liquid crystal materials are filled in a cell gap. It constitutes a dielectric liquid crystal element.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel carboxylic acid ester compound, an antiferroelectric liquid crystal compound, an antiferroelectric liquid crystal composition and an antiferroelectric liquid crystal device.

[0002]

BACKGROUND OF THE INVENTION Liquid crystal display devices are currently widely used because they can be driven at low voltage and low power consumption and can be made smaller and thinner. However, they are driven in TN (twisted nematic) mode. Liquid crystal display devices that do this are the mainstream.

However, this TN liquid crystal element has a drawback that the optical switching time is long. In contrast,
A liquid crystal element utilizing the electro-optical effect of a ferroelectric liquid crystal (hereinafter referred to as a ferroelectric liquid crystal element) has an extremely short optical switching time as compared with the above-mentioned TN liquid crystal element or STN liquid crystal element, and further, before and after optical switching. In both cases, since the liquid crystal element exhibits an optical memory property because the alignment state of the ferroelectric liquid crystal compound is stably maintained, it is suitable for use as a display element for a moving image display device.

However, the ferroelectric liquid crystal device has a residual image (switching failure), is vulnerable to mechanical shock, and has a chevron structure (alignment structure bent in a dogleg shape) or a twist structure (long molecular axis). Since it is easy to take a structure in which liquid crystal molecules are twisted and aligned along the direction, there is a drawback that high contrast and stable optical memory property cannot be obtained.

A liquid crystal element utilizing the electro-optical effect of an antiferroelectric liquid crystal (hereinafter referred to as an antiferroelectric liquid crystal element) exhibits optical switching equivalent to that of the above ferroelectric liquid crystal element and has a predetermined size. It is common to the ferroelectric liquid crystal element in that the direction of spontaneous polarization between adjacent liquid crystal molecules becomes the same when a voltage exceeding it is applied, that is, a ferroelectric state occurs.

However, in the antiferroelectric liquid crystal element, when the magnitude of the voltage is brought close to zero from the ferroelectric state and the magnitude of the voltage is made smaller than a predetermined value, the spontaneous polarization between the adjacent liquid crystal molecules are opposite to each other. That is, the antiferroelectric state.

Therefore, the antiferroelectric liquid crystal element does not cause an afterimage as in the ferroelectric liquid crystal element, and
The antiferroelectric liquid crystal element has an advantage that it is suitable for simple matrix driving.

Conventionally, it has been considered that an antiferroelectric liquid crystal is formed by orienting a compound having an optically active group (chiral portion) at the molecular end. That is, a compound having an optically active group at the molecular end has been indispensable for conventional antiferroelectric liquid crystals.

Therefore, conventionally, the range of antiferroelectric liquid crystals that can be provided is limited because a compound having an optically active group at the molecular end is indispensable, and the range of antiferroelectric liquid crystals that can be provided is limited. However, there is a limit to the improvement of liquid crystal physical properties.

When two types of antiferroelectric liquid crystals having the same spontaneous polarization in the antiferroelectric liquid crystal element are compared, the antiferroelectric liquid crystal having a large tilt angle is electro-optical. It is desirable to obtain a liquid crystal device having a high response speed and a high contrast.

For example, a pair of polarizing plates are arranged on both sides of the liquid crystal cell so that light passes through one polarizing plate, the liquid crystal cell and the other polarizing plate in this order, and antiferroelectricity is provided between the electrodes of the liquid crystal cell. In an antiferroelectric liquid crystal element formed by filling a liquid crystal and arranging the pair of polarizing plates in a crossed Nicols position, that is, the polarization directions controlled by the respective polarizing plates are arranged to be orthogonal to each other, The light transmittance of the antiferroelectric liquid crystal element, that is, the light transmittance of light transmitted through one polarizing plate, a liquid crystal cell and the other polarizing plate in this order is expressed by the following formula (i): I = I ₀ sin ² 2θsin ² (πΔn · d / λ) (i) (In the above formula (i), I ₀ represents incident light intensity, and I represents
Represents the intensity of transmitted light, θ represents the tilt angle, Δn represents the refractive index anisotropy (difference between the refractive index for ordinary light and the refractive index for extraordinary light), and d represents the cell gap of the liquid crystal cell. , Λ represents the wavelength of the incident light. ), And becomes maximum when the tilt angle θ is 45 degrees. This tilt angle θ varies depending on the type of the antiferroelectric liquid crystal filled between the electrodes of the liquid crystal cell, but it is advantageous to obtain the tilt angle θ as close as possible to 45 degrees in order to obtain a liquid crystal element with high contrast.

By the way, the antiferroelectric liquid crystal is switched by the direct interaction between the spontaneous polarization and the electric field.
That is, it changes electro-optically. Therefore, by using an antiferroelectric liquid crystal having a large spontaneous polarization, the electro-optical response speed of the antiferroelectric liquid crystal element can be increased.

However, the antiferroelectric liquid crystal tends to have a large viscosity as the spontaneous polarization increases.
Therefore, even if an antiferroelectric liquid crystal having a large spontaneous polarization is used, the electro-optical response speed of the antiferroelectric liquid crystal element may not be increased.

From the above, regarding the antiferroelectric liquid crystal, it is possible to obtain a high electro-optical response speed by not changing the magnitude of spontaneous polarization so much and increasing the tilt angle.
It can be said that it is desirable for obtaining an anti-ferroelectric liquid crystal device having a high contrast.

Therefore, at present, in the antiferroelectric liquid crystal element, the magnitude of spontaneous polarization is almost the same as that of the conventional antiferroelectric liquid crystal, and the tilt angle is larger than that of the conventional antiferroelectric liquid crystal. It is desired to provide a ferroelectric liquid crystal.

A compound having an optically active group at its molecular end is usually synthesized using an optically active alcohol, but this optically active alcohol takes time and effort to synthesize. Therefore, the conventional antiferroelectric liquid crystal has a problem that the cost is high.

On the other hand, when the present inventors produced a novel carboxylic acid ester compound and measured the liquid crystal phase of this carboxylic acid ester compound or a composition containing the same, surprisingly, the carboxylic acid Even though the ester compound does not have an optically active group at the molecular end,
A carboxylic acid ester compound or a composition containing the same exhibits an antiferroelectric liquid crystal phase, and when an antiferroelectric liquid crystal element is formed by using these antiferroelectric liquid crystal materials, conventional antiferroelectric liquid crystals are obtained. The inventors have found that it is possible to provide an antiferroelectric liquid crystal having substantially the same magnitude of spontaneous polarization and a larger tilt angle than conventional antiferroelectric liquid crystal materials, and completed the present invention.

[0018]

The object of the present invention is to provide a novel carboxylic acid ester compound which can be suitably used as an antiferroelectric liquid crystal compound or a component of an antiferroelectric liquid crystal composition, a method for producing the same and conventional antiferroelectric compounds. Liquid crystal compound or antiferroelectric material that can provide an antiferroelectric liquid crystal that has almost the same magnitude of spontaneous polarization as the organic liquid crystal and has a larger tilt angle than conventional antiferroelectric liquid crystal materials. Liquid crystal composition, and an antiferroelectric liquid crystal compound or an antiferroelectric liquid crystal device (including a liquid crystal display device) using the antiferroelectric liquid crystal composition.

Another object of the present invention is to provide the antiferroelectric liquid crystal compound or the antiferroelectric liquid crystal composition at low cost.

[0020]

SUMMARY OF THE INVENTION The carboxylic acid ester compound according to the present invention has the following formula (I): R—X—A ¹ —Y—A ² —CO ₂ —CH (C _n H _{2n + 1} ) ₂ (I) [In the formula (I), R is a group selected from an alkyl group having 3 to 20 carbon atoms, a polyfluoroalkyl group having 3 to 20 carbon atoms, and one or two non-adjacent groups present in these groups. The above -CH ₂ -group or -CF ₂ -group represents one group selected from the group substituted with -O- group, X represents -O- or a single bond, and A ¹ and A ² Are each independently

[0021]

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A group selected from (provided that A ¹ and A ²
At least one of

[0023]

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It is ), And Y is -COO-, -OCO,
_{-CH 2 CH 2 -, - CH} 2 O -, - OCH 2 -, - CONH -, - NHCO -, - SCO-,
Represents one group selected from —COS—, —CH ₂ S— and —SCH ₂ —, and n represents an integer of 2 to 8].

In the antiferroelectric liquid crystal compound according to the present invention, the above formula (I) (R, X, A ¹ , A ² , Y and n in the formula (I) have the same meanings as described above.) It is characterized by being represented by.

The antiferroelectric liquid crystal composition according to the present invention is characterized by containing the carboxylic acid ester compound represented by the above formula (I). The antiferroelectric liquid crystal device according to the present invention is a liquid crystal device including a liquid crystal cell, and the antiferroelectric liquid crystal compound or the antiferroelectric liquid crystal compound according to the present invention as described above is provided between electrodes inside the liquid crystal cell. It is characterized in that it is filled with a liquid crystal composition.

[0027]

DETAILED DESCRIPTION OF THE INVENTION Carboxylic Acid Ester Compound First, the carboxylic acid ester compound according to the present invention will be specifically described.

The novel carboxylic acid ester compound according to the present invention has the following formula (I): R—X—A ¹ —Y—A ² —CO ₂ —CH (C _n H _{2n + 1} ) ₂ (I) It is represented by.

In the above formula (I), R is a group selected from an alkyl group having 3 to 20 carbon atoms, a polyfluoroalkyl group having 3 to 20 carbon atoms, and one or adjacent groups present in these groups. Represents _two or more -CH ₂ -groups or -CF ₂ -groups each of which is substituted with an -O- group,
X represents -O- or a single bond, and A ¹ and A ² are each independently

[0030]

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Represents a group selected from A ¹ and A ²
At least one of

[0032]

[Chemical 12]

And Y is --COO--, --OCO, --CH ₂ CH _2- ,
_{-CH 2 O -, - OCH 2} -, - CONH -, - NHCO -, - SCO-, -COS-, -C
Represents one group selected from H ₂ S- and -SCH _2- , and n is
It represents an integer of 2 to 8.

When R is an alkyl group having 3 to 20 carbon atoms, the alkyl group may have any of linear, branched or alicyclic form. In addition, the above R
Is an alkyl group having 3 to 20 carbon atoms in which two or more -CH ₂ -groups which are not adjacent to each other are substituted with -O- groups, such groups include (2-hexyloxy) ethoxy group. ,
[(2'-butoxy) -2-ethoxy] ethoxy group, nonyloxymethyl group and the like can be mentioned.

Examples of the carboxylic acid ester compound represented by the above formula (I) are shown in Table 1 below.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

Among the carboxylic acid ester compounds shown in Table 1 above, in the examples described later, R is 3 to 2 carbon atoms.
An alkyl group of 0 or an alkoxy group of ² to 19 carbon atoms, A ¹ and A ² are each independently

[0040]

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Represents one group selected from the group consisting of at least one of A ¹ and A ² .

[0042]

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And carboxylic acid ester compounds in which Y is —COO—, and particularly carboxylic acid ester compounds in which R is a decyl group or a decyloxy group and n is 3.

The fact that the carboxylic acid ester compound represented by the above formula (I) is obtained in the present invention means that the FD-mass spectrum and ¹
Confirmed by 1 H-NMR spectrum.

Particularly, among the carboxylic acid ester compounds represented by the above formula (I), the carboxylic acid ester compounds in which Y is —COO— exemplified in the examples described later are prepared, for example, as follows. Manufactured. (1) the following formula _{(II): Ph-CH 2} O-A 2 -COOH ... (II) ( In the formula, Ph represents a phenyl group, A ² are the same and A ² in the above formula (I) A compound represented by the formula: HOCH (C _n H _{2n + 1} ) ₂ and, for example, 1,2,3,4-tetrahydro-6-benzyloxynaphthalenecarboxylic acid.
In an alcohol is reacted represented by the following formula _{(III)) Ph-CH 2} O-A 2 -CO 2 CH (C n H 2n + 1) 2 ... carboxylic acid ester compound represented by (III), For example 1,2,3,4-
Obtain tetrahydro-6-benzyloxynaphthalenecarboxylic acid ester. (2) The obtained carboxylic acid ester compound represented by the above formula (III), for example, 1,2,3,4-tetrahydro-6-benzyloxynaphthalenecarboxylic acid ester, in a solvent such as tetrahydrofuran on palladium / carbon A hydroxy compound represented by the following formula (IV): HO-A ² —CO ₂ CH (C _n H _{2n + 1} ) ₂ (IV) by reducing with hydrogen gas in the presence of a reducing catalyst such as For example, 1,2,3,4-tetrahydro-6-hydroxynaphthalenecarboxylic acid ester is obtained. (3) A hydroxy compound represented by the above formula (IV), for example, 1,2,3,4-tetrahydro-6-hydroxynaphthalenecarboxylic acid ester and the following formula (V): R—X—A ¹ —COOH. (V) (in the formula, X and a ¹ are each an X and a ¹ and the same group in the above formula [I].) carboxylic acid represented by, and for example, 4-alkoxy-biphenyl carboxylic acid ,
A carboxylic acid ester compound represented by the above formula (I) is produced by reacting in a methylene chloride solvent in the presence of 4-N, N-dimethylaminopyridine while adding an N, N'-dicyclohexylcarbodiimide solution dropwise. It

The compound represented by the above formula (II) is 1,
In the case of 2,3,4-tetrahydro-6-benzyloxynaphthalenecarboxylic acid, this 1,2,3,4-tetrahydro-6-benzyloxynaphthalenecarboxylic acid is produced, for example, as follows. (I) A mixture of 6-alkoxynaphthalene-2-carboxylic acid and 1,2-diethoxyethane was refluxed in the presence of metallic sodium while adding isoamyl alcohol dropwise to give 1,2,3,4-tetrahydro. -6-Alkoxynaphthalene-2
-Get the carboxylic acid. (Ii) 1,2,3,4-tetrahydro-6-alkoxynaphthalene-2-carboxylic acid thus obtained is reacted with acetic acid and hydrobromic acid to give 1,2,3,4-tetrahydro- 6-Hydroxynaphthalene-2-carboxylic acid is obtained. (Iii) 1,2,3,4-tetrahydro obtained as described above
When -6-hydroxynaphthalene-2-carboxylic acid and benzyl bromide are reacted in the presence of potassium hydroxide, 1,2,3,
4-Tetrahydro-6-benzyloxynaphthalenecarboxylic acid is obtained.

In the above formula (I), when Y is -OCO-, the compound represented by the following formula (V) is used instead of the compound represented by the above formula (II).
_{I): Ph-CH 2 OCO} -A 2 -COOH ... (VI) ( In the above formula, A ² is the formula (I) using the same group and A ² in) a compound represented by. the formula compounds represented by (VI) and _{formula: HOCH (C n H 2n +} 1) the following formula obtained by reacting an alcohol represented by _{2 (VII): Ph-CH} 2 OCO- A ² —COOCH (C _n H _{2n + 1} ) ₂ (VII) (wherein A ² has the same meaning as described above) in a solvent such as tetrahydrofuran and a reduction catalyst such as palladium / carbon. When reduced with the presence of hydrogen gas of formula ^{(VIII): HOOC-a 2} -CO 2 CH (C n H 2n + 1) 2 ... (VIII) ( in the above formula, a ^2, as well as the A carboxylic acid represented by formula (VIII) is obtained, and the carboxylic acid represented by formula (VIII) and the following formula (IX): R—X—A ¹ —OH IX] (in the above formula, X and A ¹ are the same groups as X and A ¹ in the above formula (I), respectively).

In the above formula (I), Y is --CH ₂ CH _2- , --CH ₂ O--,
_{-OCH 2 -, - CONH -,} - NHCO -, - SCO-, -COS-, -CH 2 S- or -SCH ₂ - if it is, in advance, the following equation in accordance with a conventional method (X): R-X- a in ^{1 -Y-a 2 -COOH ... (} X) ( the above formulas, R, X, Y, a ¹ and a ^2, respectively refer to the corresponding code in the same group in the above formula (I). ) Is previously synthesized, and the carboxylic acid represented by the formula (X) and the formula: HOCH (C _n H
It is obtained by reacting with an alcohol represented by _{2n + 1} ) ₂ .

Liquid Crystal Compound The antiferroelectric liquid crystal compound according to the present invention is characterized by being represented by the above formula [I]. That is, the antiferroelectric liquid crystal compound according to the present invention is selected from the range of the carboxylic acid ester compound represented by the above formula (I).

In order to obtain an antiferroelectric liquid crystal compound having a wide temperature range of the antiferroelectric liquid crystal phase, it is desirable that the antiferroelectric liquid crystal molecules have a rigid structure. From such a point, the above formula ( In I), R is a linear group, particularly n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-
It is preferably a linear alkyl group such as an undecyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group, etc., Y is preferably -COO- or -CH ₂ O-, and A is ¹ and A ² are

[0051]

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It is preferably ^one group selected from the following, and at least one of A ¹ and A ² is

[0053]

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It is preferable that When a liquid crystal cell is filled with the antiferroelectric liquid crystal compound according to the present invention, the antiferroelectric liquid crystal compound according to the present invention may be used alone, or may be mixed with a known liquid crystal compound and an additive. You may use it.

Liquid Crystal Composition Next, the liquid crystal composition according to the present invention will be described. The liquid crystal composition according to the present invention is characterized by containing a carboxylic acid ester compound represented by the above formula (I).

The liquid crystal composition according to the present invention may be composed only of a mixture of two or more kinds of carboxylic acid ester compounds represented by the above formula (I), but other liquid crystal compounds and known additives may be used. It may be composed of a mixture of one or more of

Other liquid crystal compounds used in the liquid crystal composition according to the present invention include

[0058]

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[0059]

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[0060]

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[0061]

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Examples thereof include compounds having a divalent cyclic group and having an optically active group at the molecular end. When the antiferroelectric liquid crystal composition according to the present invention comprises a mixture of the carboxylic acid ester compound represented by the above formula (I) and another liquid crystal compound, the carboxylic acid ester compound represented by the above formula (I) Is the total amount of antiferroelectric liquid crystal composition 10
1 to 99 parts by weight, preferably 5 to 75 parts, relative to 0 parts by weight
Desirably, parts by weight are used. That is, the above formula (I)
The carboxylic acid ester compound represented by is used as a main agent and an auxiliary agent of the antiferroelectric liquid crystal composition depending on the type of other liquid crystal compounds.

The antiferroelectric liquid crystal composition according to the present invention may be used in a known amount such as a conductivity imparting agent or a life improving agent in an amount within a range that does not impair the antiferroelectricity of the liquid crystal composition, if necessary. You may contain the additive.

Anti-Ferroelectric Liquid Crystal Element The anti-ferroelectric liquid crystal element according to the present invention is a liquid crystal element having a liquid crystal cell, and includes a liquid crystal display element, which is usually a liquid crystal cell between electrodes inside the liquid crystal cell. The antiferroelectric liquid crystal compound or the antiferroelectric liquid crystal composition according to the present invention as described above is filled between the electrodes of the pair of substrates with electrodes provided in the cell.

One of the pair of electrode-attached substrates may be transparent, and the other may be transparent or opaque. When one of the electrode-attached substrates is opaque, the liquid crystal element including the liquid crystal cell can be used as a reflective liquid crystal element in a liquid crystal display element or the like. On the other hand, when the substrate with both electrodes is transparent, the liquid crystal element including this liquid crystal cell can be used as an optical switching element, an optical modulation element or the like as a transmissive liquid crystal element.

An alignment film may be provided on at least one electrode surface of the pair of electrode-attached substrates. Incidentally, the alignment film means a layer for aligning the liquid crystal compound or liquid crystal composition according to the present invention in contact with the liquid crystal cell in a predetermined direction in a liquid crystal cell, for example, forming a polyimide film on an electrode of a substrate with an electrode, It is obtained by rubbing the surface of this polyimide film in a predetermined direction.

Further, in the liquid crystal cell, a spacer is provided between the electrodes in order to keep the distance between the electrodes inside the liquid crystal cell constant. As the spacer, a film having a constant film thickness, spherical particles having a uniform particle diameter, fiber pieces having a uniform thickness, or the like is used. When a film having a certain thickness is used as the spacer, the spacer is usually provided in the peripheral edge portion between the electrodes inside the liquid crystal cell. When spherical particles having a uniform particle size or fiber pieces having a uniform thickness are used as spacers, these spacers are used by mixing with the liquid crystal compound or liquid crystal composition according to the present invention.

When the substrate of the liquid crystal cell contains impurities such as alkali metal, these impurities should not interfere with the liquid crystal compound or liquid crystal composition according to the present invention through the electrodes of the substrate with electrodes or the electrodes. An alkali passivation film or the like may be provided between the substrate of the electrode-attached substrate and the electrode.

In the antiferroelectric liquid crystal device according to the present invention, the antiferroelectric liquid crystal compound or the antiferroelectric liquid crystal composition according to the present invention filled in the liquid crystal cell is in the antiferroelectric liquid crystal phase state. When a voltage is applied between the electrodes of the liquid crystal cell, the orientation state of the antiferroelectric liquid crystal phase changes among the three stable states depending on the polarity and magnitude of the voltage. For example, the ferroelectric state on the positive voltage side When the voltage is brought close to zero, the state changes to the antiferroelectric state, and the polarization direction of the light incident on the liquid crystal cell changes in the liquid crystal cell according to the change in the alignment state.

When display, light switching or light modulation is performed by utilizing such a change in the polarization direction of light, the antiferroelectric liquid crystal device according to the present invention is usually provided with a polarizing plate, a polarizing beam splitter, 1 / When polarization control means such as a four-wave plate is used and the antiferroelectric liquid crystal element according to the present invention is a reflective liquid crystal element, the polarization control means is provided between the observer and the liquid crystal cell, and When the antiferroelectric liquid crystal element according to the invention is a light transmission type liquid crystal element, polarization control means,
The two polarization control means are arranged in the para-Nicol position or the cross-Nicol position so that the incident light passes through the liquid crystal cell and the polarization control means in this order, so that maximum contrast can be obtained when the polarization direction of the light changes. The two polarization control means and the liquid crystal cell are positioned. However, when the incident light has only a specific polarization component, for example, a vertical polarization component or a horizontal polarization component, the polarization control means on the light incident side can be omitted and the observer wears polarizing glasses to control the output light of the liquid crystal element. When observing, the polarization control means other than the polarized glasses on the light outgoing / incident side can be omitted.

As described above, the antiferroelectric liquid crystal element according to the present invention comprises a liquid crystal cell, and the antiferroelectric liquid crystal compound or antiferroelectric compound according to the present invention as described above is provided between the electrodes inside the liquid crystal cell. It is sufficient that the dielectric liquid crystal composition is filled, and various modifications are possible depending on the application of the liquid crystal element.

The antiferroelectric liquid crystal device according to the present invention comprises a liquid crystal cell, and the antiferroelectric liquid crystal compound or the antiferroelectric liquid crystal composition according to the present invention as described above between the electrodes inside the liquid crystal cell. Since the anti-ferroelectric liquid crystal compound molecules are aligned by applying a voltage between the electrodes inside the liquid crystal cell, the tilt angle of these anti-ferroelectric liquid crystal compound molecules is It can be increased as compared with the case where a liquid crystal compound or an antiferroelectric liquid crystal composition is used.

[0073]

According to the present invention, a novel carboxylic acid ester compound is provided. This carboxylic acid ester compound is used as an antiferroelectric liquid crystal compound or as a component of an antiferroelectric liquid crystal composition.

The antiferroelectric liquid crystal compound according to the present invention is composed of the novel carboxylic acid ester compound according to the present invention and has an antiferroelectric property even though it has no optically active group at the molecular end. Shows a liquid crystal phase.

The antiferroelectric liquid crystal composition according to the present invention contains the novel carboxylic acid ester compound according to the present invention. Therefore, it is basically composed of a compound group having an optically active group at the molecular end. In comparison with the conventional antiferroelectric liquid crystal composition, it is possible to increase the alignment tilt angle of the liquid crystal compound molecule when filling between the electrodes of the liquid crystal cell and then applying a voltage between the electrodes. it can.

Further, according to the present invention, the antiferroelectric liquid crystal compound or the antiferroelectric liquid crystal composition having the above-mentioned excellent properties can be provided at a low cost.

[0077]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, R described in the following compound,
S is a code indicating different optical rotatory power.

[0078]

Example 1 6- (4-decyloxybiphenyl-4′-carbonyloxy)-
1,2,3,4-Tetrahydronaphthalene-2-carboxylic acid-4-
Butyl ester [Exemplary compound (17)]:

[0079]

[Chemical 21]

Synthesis of 1st stage 6-decyloxy-naphthalene-2-carboxylic acid 23.2 g (70.
8 mmol) and 780 ml of 1,2-diethoxyethane,
Metallic sodium 18 with stirring at 120 ° C under nitrogen atmosphere
g (780 mg atom) was added and further heated to reflux temperature.

60 g of isoamyl alcohol (6
(84 mmol) was added dropwise over 1 hour, and the mixture was reacted under reflux for 11 hours. The obtained reaction mixture was cooled to room temperature, ethanol was added to this reaction mixture to decompose metallic sodium remaining in the reaction mixture, and 20% hydrochloric acid was added to acidify the mixture.

Then, 600 ml of this water was added to separate the water phase and the organic phase, and the obtained organic phase was washed with water. Then, the organic phase was concentrated under reduced pressure to obtain 25.5 g of a solid.
By recrystallizing this solid with toluene, 1,
17.7 g (53.3 mmol) of 2,3,4-tetrahydro-6-decyloxynaphthalene-2-carboxylic acid was obtained.

Second step 1,2,3,4-tetrahydro-6-decyloxynaphthalene-2-carboxylic acid obtained in the first step 16.6 g (50 mmol) (first
250 ml and 47 ml of acetic acid)
86.5 g (0.5 mol) of% hydrobromic acid was added, and the resulting mixture was heated under reflux at 130 ° C. for 7 hours. Then, after adding distilled water to this mixture, by concentrating under reduced pressure, 1,
10.60 g (50 mmol) of 2,3,4-tetrahydro-6-hydroxynaphthalene-2-carboxylic acid was obtained.

Third step 10.60 g (50 mmol) of 1,2,3,4-tetrahydro-6-hydroxynaphthalene-2-carboxylic acid obtained in the second step, 12.85 g (75 mmol) of benzyl bromide, 85% water 6.6 g of potassium oxide (10
A mixture of 0 mmol), 0.525 g (3.5 mmol) of sodium iodide, 200 ml of ethanol, and 25 ml of distilled water was heated under reflux at 100 ° C. for 12 hours. The reaction mixture obtained was allowed to cool to room temperature, then added to cold water and recrystallized from toluene to give 1,2,3,4-tetrahydro-6-benzyloxynaphthalene-2-carboxylic acid. Acid 13.8g (46.4mmol)
I got

Fourth stage 1,2,3,4-tetrahydro-6-benzyloxynaphthalene-2-carboxylic acid obtained in the third stage 0.42 g (1.5 mmol), 4-
Heptanol 0.17 g (1,5 mmol), 4-N, N-dimethylaminopyridine 0.02 g (0.16 mmol) and methylene chloride 12 ml
A mixture of N, N'-dicyclohexylcarbodiimide
5 ml of methylene chloride solution containing 0.37 g (1.8 mmol) at room temperature,
The mixture was added dropwise with stirring over 1.5 hours.

The reaction mixture thus obtained was further reacted at room temperature for 20 hours. Then, the reaction mixture was filtered, and the obtained filtrate was concentrated. By separating this concentrate using column chromatography, a colorless transparent liquid 1,2,3,4-tetrahydro-6-benzyloxynaphthalene-2-carboxylic acid-4-heptyl ester 0.40 g
(1.05 mmol) was obtained.

Fifth step 1,2,3,4-tetrahydro-6-benzyloxynaphthalene-2-carboxylic acid-4-heptyl ester obtained in the fourth step
Hydrogen was bubbled into a mixture of 0.40 g (1.05 mmol), 5% Pd / carbon 0.20 g and tetrahydrofuran 5 ml for 72 hours at room temperature under normal pressure with stirring. The reaction mixture obtained was filtered using Celite as a filter aid, and the resulting filtrate was concentrated to give 1,2,3,4-tetrahydro-6-hydroxynaphthalene-2-carboxylic acid as a colorless transparent liquid. Acid-4
-0.29 g (1.0 mmol) of heptyl ester was obtained.

Sixth step 1,2,3,4-tetrahydro-6-hydroxynaphthalene-2-carboxylic acid-4-heptyl ester obtained in the fifth step 0.2
A mixture of 9 g (1.0 mmol), 4-decyloxybiphenyl-4'-carboxylic acid 0.35 g (1 mmol), 4-N, N-dimethylaminopyridine 0.02 g (0.16 mmol) and methylene chloride 10 ml, which were separately synthesized by a conventional method. , N, N'-dicyclohexylcarbodiimide 0.27 g (1.3 mmol) in methylene chloride solution 3 ml
Was added dropwise over 2 hours with stirring at room temperature.

The reaction mixture thus obtained was further reacted at room temperature for 4 hours. Then, the reaction mixture was filtered, and the obtained filtrate was concentrated. By separating this concentrate using column chromatography, 0.46 g of a colorless semi-solid was obtained.

The FD mass spectrum value M / e of this semi-solid was 62.
It was 6. FIG. 1 shows the ¹ H-NMR spectrum chart of the obtained semi-solid compound. From the above measurement results, this compound was identified as 6- (4-decyloxybiphenyl-4'-
Carbonyloxy) -1,2,3,4-tetrahydronaphthalene-2
-Carboxylic acid-4-heptyl ester (exemplified compound (1
7)] was identified.

The phase transition temperatures of the above exemplified compound (17) are shown in Table 2 below. In the table, Iso indicates an isotropic liquid phase,
SmA shows smectic A phase, SmC shows smectic C
Phase, SmX indicates an unidentified smectic phase, Cry
Indicates a crystalline phase, and the critical temperatures of two phases, for example, an isotropic liquid phase and a smectic A phase are shown in the table.

[0092]

[Table 4]

[0093]

Example 2 6- (4-decylbiphenyl-4′-carbonyloxy) -1,2,3,
4-tetrahydronaphthalene-2-carboxylic acid-4-heptyl
Ester [Exemplified Compound (24)]:

[0094]

Embedded image

Synthesis in the same manner as in Example 1 except that 4-decyloxybiphenyl-4′-carboxylic acid was replaced with 4-decylbiphenyl-4′-carboxylic acid in the sixth step of Example 1. This gave 0.45 g of a semi-solid.

The FD mass spectrum value M / e of this semi-solid was 61.
It was 0. FIG. 2 shows the ¹ H-NMR spectrum chart of the obtained semisolid compound. From the above measurement results, this compound is the target 6- (4-decylbiphenyl-4'-carbonyloxy) -1,2,3,4-tetrahydronaphthalene-2-carboxylic acid-4-heptyl ester [Example Compound (24)] was identified.

The phase transition temperatures of the exemplified compound (24) are shown in Table 3 below. The symbols and numerical values in the table have the same meanings as the symbols and numerical values shown in Table 2.

[0098]

[Table 5]

[0099]

Example 3 6-[(4-decyloxyphenyl) cyclohexane-4'-cal
Bonyloxy] -1,2,3,4-tetrahydronaphthalene-2-ca
Rubonic acid-4-heptyl ester [exemplary compound (79)]:

[0100]

Embedded image

Synthesis of Example 1 except that 4- (4-decyloxyphenyl) cyclohexanecarboxylic acid was used in place of 4-decyloxybiphenyl-4′-carboxylic acid in the sixth step of Example 1.
In the same manner as in the above, 0.44 g of a colorless semi-solid was obtained.

The FD mass spectrum value M / e of this semi-solid is 63.
Was 2. FIG. 3 shows the ¹ H-NMR spectrum chart of the obtained semi-solid compound. From the above measurement results, this compound shows that the desired 6-[(4-decyloxyphenyl) cyclohexane-4′-carbonyloxy] -1,2,3,4-tetrahydronaphthalene-2-carboxylic acid-4- It was identified as a heptyl ester [Exemplified Compound (79)].

The phase transition temperature of the above exemplified compound (79) is shown in Table 4 below. The symbols and numerical values in the table have the same meanings as the symbols and numerical values shown in Table 2.

[0104]

[Table 6]

[0105]

Example 4 6- (4-decyloxyphenylcarbonyloxy) -1,2,3,
4-tetrahydronaphthalene-2-carboxylic acid-4-heptyl
Ester [Exemplified Compound (86)]:

[0106]

Embedded image

Synthesis of Example 6 In the same manner as in Example 1 except that 4-decyloxybiphenyl-4′-carboxylic acid was replaced with 4-decyloxybenzoic acid in the 6th step, 0.39 g of a colorless semisolid
I got

The FD mass spectrum value M / e of this semi-solid is 55.
Was 2. FIG. 4 shows the ¹ H-NMR spectrum chart of the obtained semisolid compound. From the above measurement results, this compound is the target 6- (4-decyloxyphenylcarbonyloxy) -1,2,3,4-tetrahydronaphthalene-2-carboxylic acid-4-heptyl ester [Exemplified compound (86 )] Was identified.

The phase transition temperature of the above exemplified compound (24) is shown in Table 5 below. The symbols and numerical values in the table have the same meanings as the symbols and numerical values shown in Table 2.

[0110]

[Table 7]

[0111]

Example 5 4- (6-decyloxy-1,2,3,4-tetrahydronaphthalene
-2-carbonyloxy) benzoic acid-4-heptyl ester [exemplary compound (101)]:

[0112]

Embedded image

Synthesis of 1st stage 4-benzyloxybenzoic acid 3.42 g (15 mmol), 4-pentanol 1.74 g (15 mmol), 4-N, N-dimethylaminopyridine 0.18 g (1.5 mmol) and methylene chloride 15 ml To the mixture, 3.71 g of N, N'-dicyclohexylcarbodiimide (18
(10 mmol) in methylene chloride solution was added dropwise over 2 hours with stirring at room temperature.

The reaction mixture thus obtained was further reacted at room temperature for 12 hours. Then, the reaction mixture was filtered, and the obtained filtrate was concentrated. The concentrate was separated by column chromatography to obtain 2.64 g (8.1 mmol) of 4-benzyloxybenzoic acid-4-pentyl ester as a colorless liquid.

Step 2 In a mixture of 2.64 g (8.1 mmol) of 4-benzyloxybenzoic acid-4-pentyl ester obtained in Step 1, 0.3 g of 5% Pd / carbon and 30 ml of tetrahydrofuran at room temperature under normal pressure. Hydrogen was bubbled in with stirring for 19 hours. The resulting reaction mixture was filtered using Celite as a filter aid,
By concentrating the obtained filtrate, 4-hydroxytobenzoic acid-4-pentyl ester which is a pale yellow transparent liquid 1.8
1 g (7.7 mmol) was obtained.

Third Step 0.26 g (1.1 mmol) of 4-hydroxytobenzoic acid-4-pentyl ester obtained in the first step, 1,2,3,4-obtained in the first step of Example 1 Tetrahydro-6-decyloxynaphthalene-2-carboxylic acid 0.37 g 81.1 mmol), 4-N, N-dimethylaminopyridine 0.013 g (0.11 mmol) and methylene chloride
To a mixture of 10 ml, 5 ml of a methylene chloride solution containing 0.27 g (1.3 mmol) of N, N'-dicyclohexylcarbodiimide,
The mixture was added dropwise over 1.5 hours with stirring at room temperature.

The reaction mixture thus obtained was further reacted at room temperature for 4 hours. Then, the reaction mixture was filtered, and the obtained filtrate was concentrated. By separating this concentrate using column chromatography, 0.46 g of a colorless semi-solid was obtained.

The FD mass spectrum value M / e of this semi-solid was 55.
It was 0. FIG. 5 shows the ¹ H-NMR spectrum chart of the obtained semi-solid compound. From the above measurement results, this compound was identified as 4- (6-decyloxy-1,2,3,4-tetrahydronaphthalene-2-carbonyloxy) benzoic acid-4
-Heptyl ester [Exemplified compound (101)] was identified.

The phase transition temperatures of the above exemplified compound (101) are shown in Table 6 below. The symbols and numerical values in the table have the same meanings as the symbols and numerical values shown in Table 2.

[0120]

[Table 8]

[0121]

Example 6 of the exemplified compound (17) measured in Example 1
In order to identify the SmX phase, exemplary compound (17) and the following formula [A]:

[0122]

[Chemical formula 26]

A binary liquid crystal composition with an antiferroelectric liquid crystal compound represented by the formula (1) was prepared, and the phase transition temperature was measured when the respective compounding ratios were changed. The compounding ratio of the two components and the phase transition temperature were measured. A phase diagram showing the relationship with

This phase diagram is shown in FIG. From the results shown in FIG. 6, it was found that the SmX phase was an antiferroelectric liquid crystal phase (SmCA phase).

[0125]

Example 7, Comparative Example 1 The exemplified compound (17) obtained in Example 1 and the following formula [B]:

[0126]

Embedded image

The composition obtained by mixing the compound represented by 50:50 in a weight ratio was filled with a composition having a cell gap of 2 μm, and a polarizing plate was crossed on both sides of a light transmission type liquid crystal cell (test cell). An antiferroelectric liquid crystal device was prepared by arranging a polarizing plate, a light transmission type liquid crystal cell and a polarizing plate in this order so that light could pass therethrough.

For comparison, an antiferroelectric liquid crystal element was prepared in the same manner as above except that only the compound represented by the above formula [B] was filled in place of the above composition. In this state, the tilt angle and the magnitude of spontaneous polarization of each liquid crystal molecule were measured as follows. A tilt angle DC voltage is applied to the test cell, a positive voltage is applied to align the liquid crystal molecules in the composition inside the test cell to the ferroelectric state, and a negative voltage is applied to the composition inside the test cell. When the liquid crystal molecules in the object are oriented in the ferroelectric state, the output light of the antiferroelectric liquid crystal element becomes the darkest state, that is, the polarizing plate, the light transmission type liquid crystal cell and the polarizing plate are transmitted in this order. The test cell is rotated with respect to the above-mentioned pair of polarizing plates so that the amount of light is minimized, and the respective rotation angles θ ₁ and θ ₂ are measured.
I asked.

Tilt angle θ = (θ ₂ −θ ₁ ) / 2 Spontaneous polarization The measurement circuit shown in FIG. 7 was constructed, and 30 V was applied to the test cell in the circuit.
A square wave of / 2 μm, 100 Hz was applied, and the polarization reversal current value was measured, and this value was taken as the magnitude of spontaneous polarization.

The results are shown in Table 7 below.

[0131]

[Table 9]

[Brief description of drawings]

FIG. 1 is a novel compound obtained by the present invention.
6- (4-decyloxybiphenyl-4'-carbonyloxy)-
^{1 is} a ¹ H-NMR spectrum chart of 1,2,3,4-tetrahydronaphthalene-2-carboxylic acid-4-heptyl ester.

FIG. 2 is a novel compound obtained by the present invention.
6- (4-decylbiphenyl-4'-carbonyloxy) -1,2,3,
^{1 is} a ¹ H-NMR spectrum chart of 4-tetrahydronaphthalene-2-carboxylic acid-4-heptyl ester.

FIG. 3 is a novel compound obtained by the present invention.
6 is a ¹ H-NMR spectrum chart of 6-[(4-decyloxyphenyl) cyclohexane-4′-carbonyloxy] -1,2,3,4-tetrahydronaphthalene-2-carboxylic acid-4-heptyl ester.

FIG. 4 is a novel compound obtained by the present invention.
6- (4-decyloxyphenylcarbonyloxy) -1,2,3,
^{1 is} a ¹ H-NMR spectrum chart of 4-tetrahydronaphthalene-2-carboxylic acid-4-heptyl ester.

FIG. 5 is a novel compound obtained by the present invention.
4- (6-decyloxy-1,2,3,4-tetrahydronaphthalene
^{1 is} a ¹ H-NMR spectrum chart of -2-carbonyloxy) benzoic acid-4-heptyl ester.

FIG. 6 is a phase diagram of a binary liquid crystal composition showing that the SmX phase is an antiferroelectric liquid crystal phase.

FIG. 7 is a drawing showing a circuit used in measuring the magnitude of spontaneous polarization of liquid crystal molecules in the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07C 69/94 C07C 69/94 233/81 9547-4H 233/81 235/54 9547-4H 235 / 54 235/56 9547-4H 235/56 323/61 7419-4H 323/61 323/62 7419-4H 323/62 327/32 7106-4H 327/32 C07D 239/26 C07D 239/26 239/32 239 / 32 C09K 19/14 9279-4H C09K 19/14 19/20 9279-4H 19/20 19/22 9279-4H 19/22 19/28 9279-4H 19/28 19/30 9279-4H 19/30 19 / 34 9279-4H 19/34 G02F 1/13 500 G02F 1/13 500

Claims (7)

[Claims] 1. The following formula (I): R—X—A ¹ —Y—A ² —CO ₂ —CH (C _n H _{2n + 1} ) ₂ (I) [In the formula (I), R is A group selected from an alkyl group having 3 to 20 carbon atoms, a polyfluoroalkyl group having 3 to 20 carbon atoms, and one or two or more non-adjacent -C existing in these groups.
H ₂ -group or -CF ₂ -group represents one group selected from the group substituted with -O- group, X represents -O- or a single bond, and A ¹ and A ² are respectively Independently Represents a group selected from: and at least one of A ¹ and A ² is In it, Y _{is, -COO-, -OCO, -CH 2 CH} 2 -, - CH 2 O -, - OCH 2 -, - CON
H -, - NHCO -, - SCO-, -COS-, -CH 2 S- and -SCH ₂ - represents one group selected from, n represents an integer of 2-8. ] The carboxylic acid ester compound represented by these. 2. In the formula (1), R has 3 to 20 carbon atoms.
Is an alkyl group or an alkoxy group having 2 to 19 carbon atoms, wherein A ¹ and A ² are each independently And at least one of A ¹ and A ² represents a group selected from And Y is —COO—, The carboxylic acid ester compound according to claim 2. 3. The following formula (I): R—X—A ¹ —Y—A ² —CO ₂ —CH (C _n H _{2n + 1} ) ₂ (I) [In the formula (I), R is A group selected from an alkyl group having 3 to 20 carbon atoms, a polyfluoroalkyl group having 3 to 20 carbon atoms, and one or two or more non-adjacent -C existing in these groups.
H ₂ -group or -CF ₂ -group represents one group selected from the group substituted with -O- group, X represents -O- or a single bond, and A ¹ and A ² are respectively Independently A group selected from (wherein at least one of A ¹ and A ² is It is. ), Y is -COO-, -OCO, -CH ₂ CH _2- , -CH ₂ O-, -OCH _2- , -CON.
H -, - NHCO -, - SCO-, -COS-, -CH 2 S- and -SCH ₂ - represents one group selected from, n represents an integer of 2-8. ] An antiferroelectric liquid crystal compound represented by: 4. In the above formula (I), A ¹ and A ² are each independently One group selected from (wherein at least one of A ¹ and A ² is It is. ) Is an antiferroelectric liquid crystal compound according to claim 3. 5. In the above formula (I), Y is —COO— or —CH ₂
The antiferroelectric liquid crystal compound according to claim 4, which is O −. 6. An antiferroelectric liquid crystal composition comprising the carboxylic acid ester compound according to claim 1 or 2. 7. A liquid crystal element comprising a liquid crystal cell, wherein the liquid crystal cell is provided between electrodes inside the liquid crystal cell.
9. An antiferroelectric liquid crystal device, which is filled with the antiferroelectric liquid crystal compound according to claim 1 or the antiferroelectric liquid crystal composition according to claim 6.