JPH04198155A - liquid crystal material - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (R is straight-chain aliphatic alkyl; X is single bond or O; K and L are 1 or 2; m is >=5; n is integer of >=1; *represents asymmetric carbon atom). EXAMPLE:4-(1-Trifluoromethyl-6-ethoxyhexyloxycarbonylphenyl)4'- octyloxybiphenyl-4-carboxylate. USE:Antiferroelectric liquid crystal substance. PREPARATION:The compound of formula I wherein X is CO can be produced by reacting a compound of formula II with a compound of formula III. Another compound of formula I wherein X is single bond is obtained by reacting a compound of formula II with a compound of formula IV (R'' is straight-chain aliphatic alkyl).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel phenyl ester antiferroelectric liquid crystal material used in liquid crystal display elements.

[Prior Art] Liquid crystal display elements have been used in various small-sized display elements due to their low voltage operation, low power consumption, and ability to provide thin displays. However, with the recent expansion of the application and use of liquid crystal display elements in the information, OA-related equipment, and television fields, high-performance, large-sized liquid crystal displays with display capacity and display quality that exceed those of conventional CRT display elements have become available. Motoko's demands were rapidly increasing.

However, as long as current nematic liquid crystals are used, even with active matrix drive liquid crystal display elements used for LCD TVs, it is difficult to increase the size and reduce costs due to the complexity of the manufacturing process and low yield. do not have. Furthermore, even with a simple matrix-driven STN type liquid crystal display element, it is not necessarily easy to drive a large capacity, and there is a limit to the response time, making it difficult to display moving images. Therefore, the reality is that nematic liquid crystal display elements cannot be said to satisfy the above-mentioned requirements for high-performance, large-sized liquid crystal display elements.

[Problems to be Solved by the Invention] Under these circumstances, a liquid crystal display element using ferroelectric liquid crystal is attracting attention as a high-speed liquid crystal display element. The surface-stabilized ferroelectric liquid crystal (hereinafter abbreviated as 5SFLC) device announced by Clark and Lagarhar was noted for its unprecedentedly fast response speed and wide viewing angle, and its switching characteristics were This has been studied in detail, and many ferroelectric liquid crystals have been manufactured to optimize various physical property constants. However, due to various factors such as poor contrast due to insufficient threshold characteristics, high-speed response not being achieved, and the orientation being destroyed by mechanical shock and difficult to recover. The reality is that it has not yet been put into practical use.

Separately, the development of elements with switching mechanisms different from 5SFLC is also progressing at the same time. Switching between three stable states of liquid crystal materials with an antiferroelectric phase (hereinafter referred to as antiferroelectric liquid crystal materials) is also one of these new switching mechanisms.
al of Applied Physics, Vo
l, 2',, pp, L729, 1988).

Antiferroelectric liquid crystal elements have three stable states. That is, there are two uniform states (Ur, Ul) and a third state found in ferroelectric liquid crystal elements. Chandani et al. reported that this third state is an antiferroelectric phase (Japanese Journal of A
pplied Physics, Vol, 28.
pp, LL261. 1989゜Japanese
Journal of Applied Phys.
ics, Vol, 28, pp, L1265.198
9). Switching between such tristable states is the first characteristic of antiferroelectric liquid crystal elements. A second feature of antiferroelectric liquid crystal elements is that there is a clear threshold value for applied voltage. Furthermore, it has memory properties, which is the third characteristic of antiferroelectric liquid crystal elements. By utilizing these excellent features, a liquid crystal display element with fast response speed and good contrast can be realized.

Another major feature is that the layer structure can be easily switched by an electric field (Japanese
e Journal of Applied Phys.
ics, Vol, 2B.

pp, Li2Q, 1989. Japanese Jo
urnal of Applied Physics,
Vol, 29. (pp. ILL, 1990), thereby making it possible to produce a liquid crystal display element with extremely few defects and an ability to self-repair alignment.

As an antiferroelectric liquid crystal material, Japanese Patent Application Laid-Open No. 1-213390
, JP-A-1-316339, JP-A-1-316367,
JP-A-1-316372, JP-A-2-28128, and Liquid Crystals.

Vol.6. pp. 167.1989, but research on antiferroelectric liquid crystals has just begun, and the number of antiferroelectric liquid crystal materials known to date is small.

An object of the present invention is to provide a new antiferroelectric liquid crystal material, particularly a novel phenyl ester antiferroelectric liquid crystal material that has excellent threshold characteristics and high-speed response.

[Means for Solving the Problems] The present invention provides -Math (1) [wherein R is a straight chain aliphatic alkyl group, X is a single bond or 0
represents. K and L are 1 or 2, m is an integer of 5 or more, and n is an integer of 1 or more. Moreover, C* represents an asymmetric carbon atom. ] This is a new phenyl ester antiferroelectric liquid crystal material.

An example of the method for producing the liquid crystal material of the present invention is shown in the following reaction formula.

(1) When X=O) 10-(C6H4)K-COOH+ RBr −
--1--→RO-(C6H4) to -COOH<1>C
HffCOO-(C6)1. ) L-COOH---
-～-→CI(:IC0O-(C6H4)L-COCI
C) IaCOO-(C6H4)t-Coo-C*l((
CF3) (CH2) 1IOC, 1lz-+HO~(
C6H,) L-COO-C*H(CF3) (Ctl
z) ,,ocI,++□n+1<2> RO-(CI4)x-COO)I -1----
−−−−−−−−→(2) When X=-(single bond) R”−CbH1+ CH3COC1−→R” −C6t
(4-CUCH3R”-C6H4-COOI(+5O
C12→ R"'-C61 (4-COCI<3> (b) <2> + <3> -→ Liquid crystal material of the present invention In the above reaction formula, R, R' or R" is a straight chain aliphatic It indicates an alkyl group, and the number of carbon atoms in the alkyl group affects the phase transition temperature, melting point, etc. of the liquid crystal.

If the number of carbon atoms is too small, it will not even exhibit a liquid crystal phase, and if the number of carbon atoms is too large, the temperature range of the chiral smectic C phase or antiferroelectric phase, which is useful as a switching device, will be much higher than room temperature. may have a high melting point or exhibit properties that are undesirable for practical use. For this reason, the number of carbon atoms in R or R'' is preferably 6 to 14,
More preferably, it is 8-12.

In addition, for the antiferroelectric phase to appear, it is necessary that m in formula (1) be 5 or more. Also - CIIH2F of formula (1)
+41 0 does not have much influence on the properties of the obtained liquid crystal, but it is preferably 2 or more in order to obtain a stable liquid crystal phase.

In the present invention, CF:IC)H(OH) is used as an optically active source.
An alcohol represented by the general formula (CL)mQC,H2□1 is used, and it can be easily produced by the following route.

ChC*)ICHzCHzOTs <4>a HO- (CHz) , O)l -→Na0- (C
Hz) lI-OH-→g C, 1Hzr+, +0-(CI(z)+5-BrCnH
zn-+0-(CHz)s-MgBr <5> [Effects of the Invention 1 The present invention can provide a novel phenyl ester antiferroelectric liquid crystal material. The novel antiferroelectric liquid crystal material provided by the present invention can be used for liquid crystal displays that take advantage of its characteristics of high-speed response, switching between three stable states, bright threshold characteristics, and good memory performance. It can be used for elements.

Examples] Next, the present invention will be described in more detail with reference to Examples.
Of course, the present invention is not limited to this.

Example 1 4-(1-)lifluoromethyl-6-nitoxyhexyloxycarponylphenyl) 4°-octyloxybiphenyl-4-carboxylate (-R=Cs in formula (1)) I+t, X=O1K
=2. L=1. m=5. When n=2] 1) 4-(4'
-Production of n-octyloxy)biphenylcarboxylic acid (1)n-CJ+J-CJ<-CJ4-COOH (1)4-
(4'-hydroxy)biphenylcarboxylic acid 10.5
g, n-octyl bromide 14°0g, potassium hydroxide 6.45g, ethanol 1500ml, water 200ml
The mixture was added to a mixed solution of ml and reacted under reflux for 10 hours. Furthermore, 500 ml of water was added and stirred for 3 hours. After the reaction was completed, the mixture was made acidic by adding concentrated hydrochloric acid, and then 500 ml of the solvent was distilled off and cooled to room temperature to obtain a white solid. This was thoroughly washed with water and then recrystallized from chloroform to obtain 12.0 g of the desired product (1) as white crystals.

2) 4-acetoxy-1-(l-trifluoromethyl-
6-Ethoxyhexyloxycarbonyl)benzene (2)
Production of CH3COO-C61 (4-COO-CIH (CFi)
(C)12)SOC2H5(2) 3.5 g of 4-acetoxybenzoic acid was added to 25 ml of thionyl chloride, and the mixture was reacted under reflux for 10 hours. Next, after distilling off excess thionyl chloride, 10 ml of pyridine and 50 ml of toluene were added, and thereto were added 10 ml of pyridine and 50 ml of toluene. I-) 2.0 g of refluoro-7-ethoxy 2-hebutanol was added dropwise. After dripping 4
After heating under reflux for an hour, let it cool and add 500ml of dichloromethane.
The organic layer was washed successively with diluted hydrochloric acid, IN aqueous sodium hydroxide solution, and water, and dried over magnesium sulfate. Furthermore, the solvent was distilled off to obtain 1.9 g of crude target product (2).

3) 4-Hydroxy-1-(1-trifluoromethyl-6-ethoxyhexyloxycarbonyl)benzene (3
) Production of HO-C6H4-Coo-CI)l(CF3) (CH
2) 5OczHs (3) 1.9g of the crude compound (2) above was added to 50ml of ethanol? After the mixture was dissolved, 4 g of hensylamine was added dropwise. After further stirring at room temperature for 4 hours, the mixture was diluted with 500 ml of chloroform, washed with dilute hydrochloric acid and water in that order, and dried over magnesium sulfate. After distilling off the solvent, the residue was isolated and purified by silica gel column chromatography to obtain 1.2 g of target product (3).

4) Production of 4-(1-)lifluoromethyl-6-nitoxyhexyloxycarbonylphenyl)-4'-n-octyloxybiphenyl-4-carboxylate (4) 1.0 g of the above compound (1) , 10 ml of thionyl chloride was added, and the mixture was heated under reflux for 10 hours. After distilling off excess thionyl chloride, add 10 ml of pyridine and 60 ml of toluene, and then add 20 ml of a toluene solution containing 0.5 g of the above compound (3).
ml was added dropwise and reacted at room temperature for 10 hours. After the reaction was completed, the mixture was diluted with 500 m 2 of chloroform, washed in this order with dilute hydrochloric acid, IN aqueous sodium carbonate solution, and water, and the organic layer was dried over magnesium sulfate. Next, after distilling off the solvent,
It was isolated using a silica gel column. Then, it was recrystallized with ethanol to obtain 0.8 g of the target product (4).

The NMR spectrum of the target product (4) is shown in FIG. The phase was identified by texture observation and DSC (differential scanning calorimeter) measurement.

The phase series of compound (4) of the present invention was as follows.

In this compound, an antiferroelectric phase was observed, and a chiral smectic phase (SC*) was not observed.

43°C93°C100°C Crystal←SCA*←SA←-unisotropic phase where SA and SCA* represent the smectic A phase and antiferroelectric phase, respectively.

5) ITO with rubbed polyimide thin film
The above compound (4
) was filled in the Tokichi phase. This cell is 1.0 per minute
It was slowly cooled at °C to align the liquid crystal in the SA phase. Install the cell between perpendicular deflection plates so that the layer direction of the liquid crystal is parallel to the analyzer or polarizer, and apply ±40V to the cell.
, 0.2H2 triangular wave voltage was applied, and changes in the amount of transmitted light were measured using a photomultiplier. the result,
In the temperature range from 90°C to 43°C, a double hysteresis response history characteristic of the antiferroelectric phase was observed.

The optical response history at 80°C is shown in Figure 2.

Examples 2 to 3 In exactly the same manner as in Example 1, n-CmHzm++0-C6
H4-C6H, -COO-C6H, -COO-C*H(
CF3) (C)12) m is 9 at 5OczHs
．． Compounds No. 12 were prepared and their phases were identified by texture observation and DSC measurements. The phase series of these compounds are shown in Table 1, and all had an antiferroelectric phase.

Further, when the optical responses of these compounds were investigated in the same manner as in Example 1, 5), all of them exhibited double hysteresis characteristic of the antiferroelectric phase.

In the above table, SX indicates an unidentified liquid crystal phase.

Example 4 Production of 4-(1-1-lifluoromethyl-6-nitoxyhexyloxycarphonylphenyl)-4'-n-decylhyphenyl 4-carboxylate [-R in formula (1), C,, H2,, X=-(single bond), to=2. L=1. m='5. When n=2]
The desired product was produced in the same manner as in Example 1 except that 4'-decylbiphenyl-4-carboxylic acid was used instead of 4'-octyloxybiphenyl-4-carboxylic acid. FIG. 3 shows the NMR spectrum of the target product. When the phases were identified by texture observation and DSC measurements, the following phase sequence was observed, and a 1 antiferroelectric phase was observed, as well as a chiral smectink phase (SC*), which is a ferroelectric phase.
) was also recognized.

<-20C5°C34°C Crystal, SX←---3CA*←-3C*46”C
When the optical response of this compound was investigated in the same manner as in 5) of Example 1, it showed double hysteresis characteristic of the antiferroelectric phase.

Example 54 - (1-)Production of (1-)lifluoromethyl-6-nidoxyhexyloxycarbonylbiphenyl) 4'-octylhenshade [-In formula (1), R=CeFI+t, X- (single bond) K=1. L=2. m=5. When n=2) 1] 4
°-acetoxy-4-(1-1-lifluoromethyl-6
-ethoxyhexyloxycarbonyl)biphenyl (1)
Production CI (3c00-C6H4-C6tL-Coo-C*1
l(CI"+) (CHz) 5OcJs (1) 10 ml of thionyl chloride was added to 2.5 g of 4'-acetoxy-4-biphenylcarboxylic acid, and the mixture was heated under reflux for 6 hours. Thereafter, excess thionyl chloride was completely distilled off. 50 ml of toluene was added to the obtained acid chloride to dissolve it, and then 50 ml of pyridine was added.
ml was added.

1.4 g of 1.1.1-trifluoro-7-nitoxy-2-heptatool was added dropwise to this solution. After heating under reflux for 18 hours, the mixture was allowed to cool, 100 ml of dichloromethane was added, and the mixture was washed with hydrochloric acid, an aqueous sodium hydroxide solution, and water in that order. After drying, the solvent was removed and purified using a silica gel column chromatograph to obtain 2.5 g of the desired product.

2) 4′-hydroxy-4-(1-trifluoromethyl-6-ethoxyhexyloxycarbonyl)biphenyl (
2) Production of HO-C6H4-CJ4-COO-C*H (CF:+)
(CH2) 5OC2H5 (2) Add 15ml of ethanol and 1.2ml of benzylamine to the previously produced compound (1).
g was added thereto, and the mixture was stirred at room temperature for 1 day and night. dichloromethane 50m
1 was added and washed with hydrochloric acid and water. After drying, the solvent was removed and purified by silica gel column chromatography to obtain 2.1 g of the desired product.

3) Production of 4-(ll-lifluoromethyl-6-nitoxyhexyloxycarponylbiphenyl)4'-octylbenzoate (3) Using 1 g of p-octylbenzoic acid and 10 ml of thionyl chloride, follow the same method as in 1). Chlorinated. To the obtained acid chloride were added 20 ml of toluene and 4 ml of pyridine to form the compound (
1 g of 2) was added. After heating under reflux for about 20 hours, the mixture was allowed to cool and 50 ml of dichloromethane was added. After washing with hydrochloric acid, an aqueous sodium hydroxide solution, and water in this order, and drying, the solvent was removed and purified using a silica gel column chromatograph to obtain 0.5 g of the desired product.

The NMR spectrum of the target product is shown in FIG. The phase was identified by texture observation and DSC measurement.

What is the phase series of compound (3) of the present invention as follows? -1
7°C8°C34°C Crystal←SX+-3CA*←SA←Isotropic phase 4) The optical response of this compound was investigated in the same manner as in Example 1, 5), and the double hysteresis characteristic of the antiferroelectric phase was observed. Indicated.

Example 64-(1-)Production of 4°-octyloxyhenshade ((1-)lifluoromethyl-6-nidoxyhexyloxycarbonylbiphenyl) [-R=C, H, ? in formula (1)] , X=0.

K=1. L=2. m=5. When n=2] The desired product was produced in the same manner as in Example 5, except that p-octyloxybenzoic acid was used instead of P-octylbenzoic acid in Example 5. The NMR spectrum of the target product is shown in FIG.

When the phase was identified by texture observation and DSC measurement, the following phase series was shown, and an antiferroelectric phase was recognized.

50°C62°C, 90″C Crystal←−−3CA*←SA←Isotropic phase Also, when the optical response of this compound was investigated in the same manner as 5) of Example 1, a double hysteresis characteristic of the antiferroelectric phase was observed. showed that.

Example 7 - Preparation of 4-(14lifluoromethyl-6-nidoxyhexyloxycarbonylbiphenyl) 4'-octyloxybiphenyl-4-carboxylate [-In formula (1), R=CIIH+t, X=0.

K=2. L=2. m=5. When n=2] 4°-octyloxybiphenyl-4-carboxylic acid produced in Example 1 and 4′-hydroxy-4-( produced in Example 5)
The desired product was produced in the same manner as in Example 1 using 1-trifluoromethyl-6-ethoxyhexyloxycarbonyl)biphenyl. The NMR spectrum of the target product is shown in FIG. When the phase was identified by texture observation and DSC measurement, the following phase series was shown, and an antiferroelectric phase was recognized.

793°C140°C Crystal←-8X←-3CA*←-8C*←159°C20
9℃ ←−−3A←−−Toshiyoshi phase

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the NMR spectrum of the liquid crystal material (4) of Example I. FIG. 2 is a diagram showing the optical response history of the liquid crystal material (4) of Example 1. FIG. 3, FIG. 4, FIG. 5, and FIG. 6 are diagrams showing NMR spectra of each liquid crystal substance of Example 4.5.6.7, respectively. Patent applicant Mitsubishi Gas Chemical Co., Ltd. Agent Patent attorney Sada Kobori Text box 2 Figure -40-20+20 -L-40 Inlet voltage (V)

Claims (1)

[Claims] The following general formula (1), ▲Mathematical formulas, chemical formulas, tables, etc.▼(1) [In the formula, R is a straight-chain aliphatic alkyl group, and X is a single bond or O
represents. K and L are 1 or 2, m is 5 or more, and n is an integer on one side. Moreover, C* represents an asymmetric carbon atom. ] A novel phenyl ester antiferroelectric liquid crystal material.