JPH03123759A - Liquid crystal compound - Google Patents

Abstract

NEW MATERIAL:A halogen-containing liquid crystal compound expressed by the formula (R1 is 4-18C alkyl or aralkyl; R2 is 1-18C alkyl; R3 is haloalkyl; X is O, COO, OCO or single bond; Y is COO, OCO, CH2O or OCH2; Z is COO or O; A and B are cyclic group). EXAMPLE:4-(1,1,1-Trifluoro-2-octyloxycarbonyl)phenyl 4-decyloxy-4'- biphenylcarboxylate. USE:A ferroelectric liquid crystal compound capable of exhibiting a bistable state, especially a ferroelectric liquid crystal compound capable of showing three states (tristable state) which is a new type when the haloalkyl group is CF3 of C2F5. PREPARATION:For example, 4-benzyloxybenzoic acid is converted into an acid chloride, then reacted with an (R)-(+)- or (S)-(-)-trifluoro-2-alkanol, subsequently debenzylated and further reacted with a 4-alkyloxy-4'-biphenylcarboxylic acid chloride to afford the compound expressed by the formula.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel halogen-containing liquid crystal compound comprising an optically active halogen-containing alcohol ester or ether.

The liquid crystal compound of the present invention is a ferroelectric liquid crystal compound exhibiting a bistable state, and the haloalkyl group is CF,
Or in the case of C, F.

This is a ferroelectric liquid crystal compound that exhibits a new type of king state.

[Prior art]

As electro-optical devices using liquid crystals, electro-optical devices using nematic liquid crystals such as DSM type, TN type, GH type, and STN type have been developed and put into practical use. However, all of the devices using such nematic liquid crystals have the disadvantage that the response speed is extremely slow, ranging from several meters to several tens of meters5ec, which limits their field of application. The response speed of devices using nematic liquid crystals is slow because the torque that moves the molecules is basically based on the anisotropy of the dielectric constant.
This is because its power is not very strong. In this background, there is spontaneous polarization (Ps) and the torque is PsXE(
ferroelectric liquid crystals were developed by Mayer et al. (L e Jou
rnalde Physique, vol. 36, 19
75. Although a newer ferroelectric liquid crystal is disclosed in JP-A No. 63-307837, it is a different compound from the present invention, and in particular, the disclosure regarding the "three states" described later is do not have.

Several high-speed electro-optical devices using ferroelectric liquid crystals have already been proposed.

A typical example is one in which the twisted structure is untwisted by the force of the wall surface, and the orientation of two molecules parallel to the wall surface is changed by the polarity of the applied electric field (for example, Japanese Patent Application Laid-Open No. 107-216-1982).
(see issue).

The above method is based on the premise of the existence of a compound exhibiting two ideal states (bi-states) as shown in the electric field response waveform of FIG. However, in reality, a compound exhibiting the ideal two states has not been discovered, and the electric field response waveforms of the two-state liquid crystals synthesized so far are as shown in Figure 2, and as shown in Figure 1. No response waveform was obtained. If you try to use something with a response waveform like the one shown in Figure 2 in, for example, an optical switching circuit, the transmittance will gradually change as the applied voltage changes from e to Φ, so it will simply turn on.

The reality is that changing the applied voltage in the OFF state cannot sufficiently accomplish the purpose. Furthermore, in the two-state liquid crystals synthesized so far, it is difficult to create a monodomain state, which is the ideal molecular orientation state, in the S*c phase stage in the absence of an electric field.
This may cause disclinations (defects) or disorder of molecular orientation called twist. Therefore, it is difficult to realize the ideal two-state orientation over a large area. Furthermore, since the threshold value (voltage at which the brightness changes by a predetermined value) is low, contrast may be reduced or the viewing angle range may be narrowed when dynamic driving is performed. Furthermore, the two-state liquid crystals synthesized so far cannot exhibit hysteresis as shown in FIG. 1, but can only exhibit hysteresis as shown in FIG. 2, and therefore do not have a memory effect. Therefore, in order for the liquid crystal to maintain a stable response in the S''c phase, it is necessary to
Either the voltage υ in the figure must be applied continuously, or the high frequency must be applied continuously, and in either case, energy loss is large.

In the end, although there is a desire for a high-speed liquid crystal electro-optical device that effectively utilizes the strong coupling between the applied electric field and molecular orientation obtained in ferroelectric liquid crystals, there are still many problems with conventional ferroelectric liquid crystal electro-optical devices. The reality is that this remains the case.

Therefore, in the present invention, we not only provide a new two-state liquid crystal compound, but also realize three stable molecular orientation states with clear brightness and dark contrast without an electric field, and have clear threshold characteristics and as shown in Figure 3. The purpose of the present invention is to provide a new liquid crystal compound that can be used in a three-state liquid crystal electro-optical device that exhibits clear hysteresis, easily realizes dynamic drive, and enables high-speed response. be.

〔the purpose〕

An object of the present invention is to provide a novel liquid crystal compound exhibiting a bistable state.

Another object of the present invention is to develop a ferroelectric liquid crystal exhibiting a chirasmectic phase and a novel ferroelectric liquid crystal having a completely new three-state phase, which is different from the conventional bistable phase chirasmectic C phase (S"c phase). The object of the present invention is to provide a dielectric liquid crystal.

The above-mentioned "having a king state" means that there is a strong state between the first electrode substrate and the second electrode substrate disposed with a predetermined gap.
A liquid crystal electro-optical device in which a conductive liquid crystal is sandwiched is configured so that a voltage for forming an electric field is applied to the first and second electrode substrates, and the voltage is applied as a triangular wave as shown in FIG. 4A. When the voltage is applied, as shown in the fourth diagram, the ferroelectric liquid crystal has a molecular orientation in the first stable state (fourth diagram) in the absence of an electric field.
(■ in the diagram), and when an electric field is applied, the molecular orientation in one electric field direction is different from the first stable state (■ in the fourth diagram), and furthermore, it has a second stable state (■ in the fourth diagram). This means that it has a third stable molecular orientation state (■ in the fourth diagram) that is different from the second and second stable states in the direction of the electric field. Regarding the liquid crystal electro-optical device that utilizes this steady state, that is, the three states, the present applicant has filed a patent application filed in 1983-7.
It has been filed as No. 0212.

In contrast, "commercially available nematic liquid crystals" and two-state liquid crystals synthesized so far are shown in Figure 4B.

As seen in C, it does not have three stable states.

This new three-state ferroelectric liquid crystal exhibits revolutionary effects when used in liquid crystal displays compared to conventional nematic liquid crystals.

In contrast to the conventional type, which required a very complex structure with an active matrix driving method, the three-state ferroelectric liquid crystal requires a simple matrix type display. For this reason, in the case of the conventional type, the production process is complicated, it is difficult to enlarge the screen, and the manufacturing cost is high, whereas in the case of the king-state ferroelectric liquid crystal, the production process is an hour wheel, and the production process is 1 This is an epoch-making technology that allows for larger screens and lower manufacturing costs.

One object of the present invention is to provide a novel liquid crystal exhibiting this three-state ferroelectricity.

[Configuration of the present invention]

The present invention is based on the general formula [wherein R1 is an alkyl or aralkyl group having 4 to 18 carbon atoms, R2 is an alkyl group having 1 to 18 carbon atoms, R3 is a haloalkyl group, and X is o, coo, oco or a single bond, y ha coo.

OCO, C) 1.0 or 0CH2, Z is COO or OlA and B are cyclic groups. ] It relates to a liquid crystal compound characterized by consisting of a compound represented by these.

Note that the haloalkyl is CH2F.

CHF,,CF,,C,Fs,CCQF2. CCQ.

Examples of the cyclic group include CF, CCU□, CF2CQCF, etc., and examples of the cyclic group include cyclic groups (one or two of the hydrogen atoms may be substituted with a halogen) such as (hereinafter blank). Can be done.

The liquid crystal compound of the present invention can be produced using an optically active haloalkanol represented by the following general formula as a raw material (R□ and R3 are as described above).

This alcohol can be obtained by asymmetric synthesis, optical resolution, or the like. Especially for those with high optical purity, methods using enzymes, yeasts, or bacteria are effective. An example of the synthesis method is shown below.

Ethyl trifluoroacetate is reacted with a Grignard reagent of an alkyl bromide to obtain a trifluoroalkyl ketone. This ketone body is reduced with sodium borohydride to obtain 1-trifluoro-2-alkanol, which is then induced into an acetate ester. This ester is stereoselectively hydrolyzed by yeast or bacteria to obtain optically active 1-trifluoro-2-alkanol in the (R) or (S) form.

(Left below) CF, GOOR (R)-(+) ↓ Na0tl aqueous solution CF3 large CnH2n+z (S)-(-) In place of the above ethyl trifluoroacetate, ethyl monofluoroacetate, ethyl difluoroacetate, ethyl pentafluoroacetate, and The corresponding optically active 1-haloalkyl-2-alkanol can be obtained in a similar manner using ethyl trichloroacetate.

Next, an example of a method for synthesizing the liquid crystal compound of the present invention will be shown. 4
- Benzyloxybenzoic acid is converted into an acid chloride using a chlorinating reagent such as thionyl chloride, and (R)-(+)- or (S)
React with -(-)-trifluoro-2-alkanol to obtain an ester. After debenzylizing this ester, it can be obtained by reacting the obtained phenol with a chloride of 4-alkyloxy-4'-biphenylcarboxylic acid.

4-benzyloxybenzoic acid 4-benzyloxybenzoic acid chlorideAlso, the liquid crystal compound of the present invention can be optically activated with 4-alkyl or 4-alkoxy-4'-biphenylcarboxylic acid using a condensing agent such as dicyclohexylcarbodiimide. It can also be synthesized by a dehydration condensation reaction of a haloalkanol with a phenol derivative.

Examples of preferable optically active halogen-containing alcohols used in the present invention include the following.

1.1.1-Trifluoro-2-hexanol 1.1.
1-Trifluoro-2-heptatool 1.1.1-trifluoro-2-octatool 1.1.1-trifluoro-2-nonal 1.1.1-trifluoro-2-decanol 1.1. 1-trifluoro-2-undecanol 1
．． 1.1-trifluoro-2-dodecanol 1.1.1
-Trifluoro-2-tridecanol 1.1.1-trifluoro-2-tetradecanol 1.1.1-trifluoro-2-pentadecanol 1.1.1-trifluoro-2-hexadecanol 1 .1. L-trifluoro-2
-Heptadecanol 1.1.1-Trifluoro-2-octadecanol Further, in place of the trifluoro group, examples include a monofluoro group, a difluoro group, a pentafluoro group, a dichloromonofluoro group, and the like.

An example of the liquid crystal compound of the present invention is: carbonyl phenyl ester carbonyl) phenyl ester The key to whether or not it exhibits a steady state is as follows.

(i) In the above formula, among x, y, and z, especially Y.

When Z is an ester bond, the direction of the ester is the same, that is, Y and Z are the same, and in place of the trifluoro group in the above compound, a monofluoro group or a difluoro group is used.

Examples include compounds such as a pentafluoro group and a difluoromonofluoro group. The optically active compound and its liquid crystal derivative exist in the (R) form and the (S) form, and although it is preferable that the optical purity is high, it is not particularly limited.

Among the liquid crystal compounds represented by the above general formula of the present invention, -CO-
, or both Y and Z are 10C- for the expression of a stable state.

The same thing can be said about X.

(it) A combination in which one of (A) and (B) in the above formula is a biphenyl group and the other is a phenol group is preferable for the expression of a fixed state.

(■) R1 bonded to an asymmetric carbon atom is CF.

C
In the case of F3, the C2F5 group often exhibits a fixed state even if the orientation of the ester (i) is different, and the C2F5 group is preferable after CF and the group for displaying the fixed state.

Dependence of antiferroelectric state on skeletal structure C, H,, -0-@-@-Coo -@-Coo~CH
-C614゜■・C,H,7-CO-@-@-coo (filter C0O-CH
-C,H.

○ 7. C, Hl, -Coo %COO-@)-Coo-CH-
C.H.

Su・C,R17-OCO@BōcooshaCoo-CH-C,H
□.

× C, H, 7-0-@-Cooyu X defense C00-C: 1(-
C.H.

Ne × C, H,, -@-Coo-@-@-C0O-CIl-C
,H,.

Ma C, H, □-〇sha OCO colored picture block Coo-C0-C, Hl
.

■・ C, + (□7-0-@@-0CO-@-Coo-CH-
C, H13× [Example] Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

Example-1 4-decyloxy-41-biphenylcarvone! 114
-Synthesis of (1,1,1-trifluoro-2-octyloxycarbonyl)phenyl ester (1) 4-hydroxybenzoic acid 1,1.1-trifluoro-2-octyl ester 4-benzyloxybenzoic acid chloride 1 Dissolve .1 g in 20 mQ of methylene chloride, and add optically active 1,1
．． 1-trifluoro-2-octatool 0.74g ([
α] back = + 25.2), triethylamine 0.4g
A solution prepared by dissolving the above in 10 mQ of methylene chloride was gradually added under water cooling. After returning to room temperature and stirring for 12 hours, the reaction solution was poured into ice water and extracted with methylene chloride. The methylene chloride phase was washed with dilute hydrochloric acid, water, IN sodium carbonate, and water in this order, and then dehydrated with anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain a crude product.

This crude product was treated by silica gel column chromatography to obtain 4-benzyloxybenzoic acid 1,1.1-
0.73 g of trifluoro-2-octyl ester was obtained.

This product and 0.1 g of 10% palladium on carbon were added to ethanol to perform a debenzylation reaction in a hydrogen atmosphere.
0.53 g of 2-octyl ester was obtained.

(2) 4-n-octyloxy-4'-biphenylcarboxylic acid 4-(1,1,1-trifluoro-2-octyloxycarbonyl)phenyl ester 4-hydroxybenzoic acid synthesized in the previous section! 1* After adding 0.53 g of 1,1.1-drifluoro-2-octyl ester and 0.18 g of triethylamine to 10 mu of methylene chloride,
While cooling with water, a solution of 0.73 g of 4-n-octyloxy-4'-biphenylcarboxylic acid chloride in 10 d of methylene chloride was gradually added. After returning to room temperature and stirring for a day and night, the reaction solution was poured into water and extracted with methylene chloride. The methylene chloride phase was washed with diluted hydrochloric acid, water, IN sodium carbonate, and water in this order. After dehydration with anhydrous magnesium sulfate, the solvent was removed. After distilling off under reduced pressure, the residue was purified by silica gel column chromatography to obtain 0.4 g of the target compound ((α) sweetness = +32.2).

The target compound exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

This S*(3) means a ferroelectric other phase exhibiting a constant state.

Infrared absorption spectrum diagram (KBr
(method) is shown in Figure 8.

Example-2 4-octyl-4'-biphenylcarboxylic acid 4-(1-
Synthesis of monofluoro-2-octyloxycarbonyl) phenyl ester (1) 4-hydroxybenzoic acid l-monofluoro-2-
A solution of 1.3 g of decyl ester 4-benzyloxybenzoic acid chloride in 25 mfl of methylene chloride, 1.0 g of optically active 1-monofluoro-2-decanol, and 0.5 g of triethylamine.
A solution of 25raQ of methylene chloride was added under water cooling.
Added gradually. After returning to room temperature and stirring for 12 hours, the reaction solution was poured into ice water and extracted with methylene chloride. The methylene chloride phase was washed with dilute hydrochloric acid, water, IN sodium carbonate, and water in this order, and then dehydrated with anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain a crude product.

This crude product was treated by silica gel column chromatography to obtain 0.78 g of 4-benzyloxybenzoic acid 1-monofluoro-2-decyl ester.

This product and 0.13 g of 10% palladium on carbon were added to ethanol to carry out a debenzylation reaction in a hydrogen atmosphere to obtain 0.6 g of 4-hydroxybenzoic acid 1-monofluoro-2-decyl ester.

(2) 4-n-octyl-4'-biphenylcarboxylic acid 4-(1-monofluoro-2-decyloxycarbonyl)phenyl ester 4-hydroxybenzoic acid 1-monofluoro-2-decyl ester synthesized in the previous section 0 .6g and triethylamine 0
．． After adding 2 g of 4-n-octyl-4'-biphenylcarboxylic acid chloride to 25 ml of methylene chloride, a solution of 0.76 g of 4-n-octyl-4'-biphenylcarboxylic acid chloride in 25 ml of methylene chloride was gradually added under water cooling. After returning to room temperature and stirring for a day and night, the reaction solution was poured into water and extracted with methylene chloride. The methylene chloride phase was washed with diluted hydrochloric acid, water, IN sodium carbonate, and water in this order. After dehydration with anhydrous magnesium sulfate, the solvent was removed. After distilling off under reduced pressure, the residue was purified by silica gel column chromatography to obtain 0.8 g of the target compound ((α) sweet = -20,0°).

The target compound exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 9.

Example-3 4-octyl-4'-biphenylcarboxylic acid 4-(1-
Synthesis of difluoro-2-octyloxycarbonyl) phenyl ester The procedure was carried out in the same manner as in Example 2, using 1,1-difluoro-2-decyl alcohol in place of 1-monofluoro-2-decanol to obtain the target compound ([α ] Amase + 15.
3°) was obtained.

The target compound exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 10.

Example-4 4-octyloxy-4'-biphenylcarboxylic acid 4-
Synthesis of (l-monofluoro-2-decyloxycarbonyl)phenyl ester (1) 4-hydroxybenzoic acid 1-monofluoro-2-
Dissolve 1.3 g of decyl ester 4-benzyloxybenzoic acid chloride in 25 ml of methylene chloride, and add 1.0 g of optically active 1-monofluoro-2-decanol ([α] Amase-7.2).
A solution of 0.5 g of triethylamine dissolved in 25n+Q methylene chloride was gradually added under water cooling. After returning to room temperature and stirring for 12 hours, the reaction solution was poured into ice water, extracted with methylene chloride, and the methylene chloride phase was mixed with dilute hydrochloric acid, water, and I
After washing with N sodium carbonate and water in this order and dehydrating with anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure to obtain a crude product.

This crude product was treated by silica gel column chromatography to obtain 0.78 g of 4-benzyloxybenzoic acid 1-monofluoro-2-decyl ester.

This product and 0.13 g of 10% palladium on carbon were added to ethanol to carry out a debenzylation reaction in a hydrogen atmosphere to obtain 0.6 g of 4-hydroxybenzoic acid 1-monofluoro-2-decyl ester.

(2) 4-n-octyloxy-4'-biphenylcarboxylic acid 4-(1-monofluoro-2-decyloxycarbonyl)phenyl ester 4-hydroxybenzoic acid 1-monofluoro-2-decyl ester synthesized in the previous section 0.6g and triethylamine 0
．． After adding 2 g of 4-n-octyloxy-4'-biphenylcarboxylic acid chloride to 25 mQ of methylene chloride, a solution of 0.8 g of 4-n-octyloxy-4'-biphenylcarboxylic acid chloride in 25a+Q methylene chloride was gradually added. After returning to room temperature and stirring for a day and night, the reaction solution was poured into water and extracted with methylene chloride. The methylene chloride phase was washed with diluted hydrochloric acid, water, IN sodium carbonate, and water in this order. After dehydration with anhydrous magnesium sulfate, the solvent was removed. After distilling off under reduced pressure, it was purified by silica gel column chromatography,
0.9 g of the target compound ((α) Amase-18,8) was obtained.

The target compound exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 11.

Example-5 4-octyloxy-41-biphenylcarboxylic acid 4-
(1,1-difluoro-2-decyloxycarbonyl)
Synthesis of phenyl ester The procedure was repeated in the same manner as in Example 4 using 1,1-difluoro-2-decyl alcohol in place of 1-monofluoro-2-decanol to obtain the target compound ([α] was also 5=+8
．． 3) was obtained.

The target compound exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 12.

Example-6 4-octyloxy-4'-biphenylcarboxylic acid 1-
Monofluoro-2-decyl ester After adding 0.1 g of optically active 1-monofluoro-2-decyl alcohol and 0.06 g of triethylamine to methylene chloride 10a+Q, 4-n-octyloxy-4'-biphenyl was added under water cooling. Carboxylic acid chloride O 122g methylene chloride 10m
Q solution was added gradually.

After returning to room temperature and stirring for a day and night, the reaction solution was poured into water, extracted with methylene chloride, and the methylene chloride phase was mixed with dilute hydrochloric acid, water,
After sequentially washing sodium INIA acid and water and dehydrating over anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure and purified by silica gel column chromatography to obtain 0.16 g of the target compound.

The target compound above was analyzed using a polarizing microscope i using a hot stage.
As a result, six phases were observed up to 34.4°C.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 13.

Example-7 4-octyloxy-4'-biphenylcarboxylic acid 1.
1-difluoro-2-decyl ester Example-6 1-
Synthesis was performed in the same manner using optically active 1,1-difluoro-2-decyl alcohol in place of monofluoro-2-decyl alcohol.

The above target compound was analyzed using a polarized light microscope Wa using a hot stage.
Due to S, six equal phases were exhibited up to -30°C.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 14.

Example-8 4-octyloxybenzoic acid 4-(1-monofluoro-
2-decyloxycarbonyl)phenyl ester (1) 4-hydroxybenzoic rIt1-monofluoro-
Optically active l-monofluoro-
2-decanol 0.14g, triethylamine 0°07
A solution of g dissolved in methylene chloride IOmQ was cooled with water.
Added gradually. After returning to room temperature and stirring for 12 hours, the reaction solution was poured into ice water and extracted with methylene chloride. The methylene chloride phase was washed with dilute hydrochloric acid, water, IN sodium carbonate, and water in this order, and then dehydrated with anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain a crude product.

This crude product was treated by silica gel column chromatography to obtain 0.13 g of 4-benzyloxybenzoic acid 1-monofluoro-2-decyl ester.

This product and 0.015 g of 10% palladium on carbon were added to ethanol to perform a debenzylation reaction in a hydrogen atmosphere.
Decyl ester 0.1[ was obtained.

(2) 4-Octyloxybenzoic acid 4-(1-monofluoro-2-decyloxycarbonyl)phenyl ester 0.1 g of 4-hydroxybenzoic acid 1-monofluoro-2-decyl ester synthesized in the previous section and 0.0 g of triethylamine
．． After adding 0.4 g of 4-n-octyloxybenzoic acid chloride to 10 nJl of methylene chloride, 0.1 g of 4-n-octyloxybenzoic acid chloride was added under water cooling.
g of methylene chloride 10+a12 solution was gradually added. After returning to room temperature and stirring for a day and night, the reaction solution was poured into water, extracted with methylene chloride, and the methylene chloride phase was mixed with dilute hydrochloric acid, water, and I
N Sodium carbonate.

After sequentially washing with water and dehydrating with anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure, and then purified by silica gel column chromatography to obtain 0.13 g of the target compound.

The above target compound was analyzed using a polarizing microscope I using a hot stage.
l! As a result, six phases were observed up to 30°C.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 15.

Example-9 4-octyloxybenzoic acid 4-(1,1-difluoro-2-decyloxycarbonyl)phenyl ester Optically active 1,1-difluoro instead of 1-monofluoro-2-decanol in Example-8 It was synthesized in a similar manner using -2-decyl alcohol.

The above target compound was analyzed using a polarized light microscope AI using a hot stage.
It showed six equal phases up to -30°C.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 16.

Example-10 4-octyloxy-4'-biphenylcarboxylic acid 4-
Synthesis example of (1,1,1,2,2-pentafluoro-3-undecyloxycarbonyl)phenyl ester-
The same procedure was repeated using optically active 1,1,1,2.2-pentafluoro-3-undecyl alcohol in place of 1-monofluoro-2-decanol in 4 to obtain the target compound.

The target compound exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 17.

Example-11 4-n-octyloxy-4'-biphenylcarboxylic acid 4-(l-chloro-1,1-difluoro-4-phenyl-2-butyloxycarbonyl) phenyl ester Example-10-1.1 ,1,2.2-pentafluoro-3-
Optically active 1-chloro-1゜1 instead of undecanol
The target compound was synthesized in the same manner using -difluoro-4-phenyl-2-butanol.

This material exhibited liquid crystallinity, and the following phase transition temperature was confirmed using a polarizing microscope using a hot stage.

Infrared absorption spectrum diagram (KBr
method) is shown in Figure 18.

Example-12 Example-10 was applied to a liquid crystal cell with a cell thickness of 2.5 μm having a rubbed polyimide alignment film on an ITO electrode substrate.
A liquid crystal thin film cell was prepared by filling the obtained liquid crystal compound in six phases.

This thin film cell was slowly cooled with a temperature gradient of 0.1 to 1.0°C/1 minute to orient the SA phase, and a square wave of ±15 V and 10 Hz was applied to the cell, and a photomultiplier-Nakbe optical microscope was used. When the electro-optical response operation was detected, as shown in FIG. 5, an electro-clinic effect (b) which optically responded to the applied electric field (a) in the SA phase was observed. Example 1 Compounds 2.3, 4, 5 and 9 had the same effect! It was noticed.

Example-13 Two liquid crystal cells were prepared in exactly the same manner as in Example 12.
A polarizing microscope equipped with a photomultiplier with two polarizing plates perpendicular to each other is shown with the direction of the long axis of the molecule and the polarizer being 2 when no voltage is applied.
They were arranged at an angle of 2.5°. This liquid crystal cell is 0.1
It was gradually cooled to the S'' (3) phase with a temperature gradient of ~1.0°C/1 minute. After further cooling, a triangular wave voltage (a) of ±30V, 10Hz was applied in the temperature range of 76°C to 39°C.
FIG. 6 shows the case where . The light transmittance changes into three states (c): a dark state when the applied voltage is in the negative range, an intermediate state in the 0 volt range, and a bright state in the positive range (c), and the peak of the polarization-inverted current waveform corresponds to this. (b) was also observed, and it was confirmed that there are three stable alignment states of liquid crystal molecules.

The same effect was observed for the other compounds of Example 1 as well.

〔effect〕

All of the novel liquid crystals of the present invention exhibit a bistable state, and also exhibit an electroclinic effect as shown in FIG. 6 in the SA phase. The present invention further enriches conventional liquid crystal materials. In particular, in the present invention, the new liquid crystals in which R3 is CF3 and C2F all exhibit stable three states, and have wide applications such as display devices and switching devices using these.

[Brief explanation of the drawing]

Figure 1 shows the hysteresis of an ideal two-state liquid crystal that has not been obtained in reality, Figure 2 shows the hysteresis of two-state liquid crystals that have actually been synthesized to date, and Figure 3 shows the hysteresis of a three-state liquid crystal according to the present invention. Each indicates the hysteresis of the liquid crystal.
In both Figures 1 to 3, the horizontal axis represents the applied voltage, and the vertical axis represents the transmittance (%).
) is shown. In FIG. 4, A shows the optical response characteristics of a triangular wave applied, B shows the optical response characteristics of a commercially available nematic liquid crystal, C shows the two-state liquid crystal synthesized so far, and D shows the optical response characteristics of a king-state liquid crystal. Figure 5 shows the three-state switching of the compound of the present invention. In Figure 5, a indicates the triangular wave voltage applied to the liquid crystal electro-optical element, C indicates the polarization inversion current, and C in the figure indicates the triangular wave voltage applied to the liquid crystal electro-optical element. Fig. 3 shows the change in light transmittance with respect to the triangular wave voltage of a. Figure 6 shows the electroclinic effect, in which a shows the alternating voltage applied to the liquid crystal electro-optical element, and part a shows the change in light transmittance with respect to the alternating voltage. , FIG. 7 shows the three-state response waveform at 2011z, ±30V of the novel liquid crystal compound of the present invention obtained in the example. In both Figures 6.7, the straight triangular wave is the applied voltage. The horizontal axis shows the passage of time, the vertical axis shows the voltage in the case of a triangular wave, and the curve shows the transmittance (%). 8 to 18 show infrared absorption spectra of the compounds obtained in Examples 1 to 11.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R_1 is an alkyl or aralkyl group having 4 to 18 carbon atoms, R_2 is an alkyl group having 1 to 18 carbon atoms, R_
3 is a haloalkyl group. X is O, COO, OCO or a single bond, Y is COO, O
CO, CH_2O or OCH_2, Z represents COO or O, A and B represent a cyclic group. ] A liquid crystal compound characterized by comprising a compound represented by the following.