JPS63183983A - Liquid crystal material and liquid crystal element produced by using said material - Google Patents

Abstract

PURPOSE:To provide a novel ferroelectric liquid crystal material consisting of a specific phenylpyrimidine liquid crystal compound, having high chemical stability and broad temperature range of Sc* phase and suitable for blending. CONSTITUTION:The objective liquid crystal material is composed of a compound of formula (n is 1-18; m is 0 or 1; l is 1-5; * represents asymmetric carbon atom). The above compound is e.g. 2-(4'-n-octylphenyl)-5-[4'-(+)-2- methylbutoxyphenyl]pyrimidine, which can be synthesized by reacting 4-no- octylbenzamidine with 2-[4-(+)-2-methylbutoxyphenyl]-3-ethoxyacrolein in the presence of sodium methylate, treating with an acid and extracting the product with toluene.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a novel ferroelectric liquid crystal material and a liquid crystal element using the same.

(Prior Art) Liquid crystal elements are widely used in electro-optical devices such as wristwatches, calculators, personal computer displays, and pocket color televisions. However, the electro-optical response time of currently used nematic liquid crystals is approximately 50
Since it is slow at mSec, its use in fields where high-speed response is required is limited. In addition, we are reaching the limit in terms of display capacity.

On the other hand, since ferroelectric liquid crystals exhibit high-speed response on the μsec scale, their practical use is expected to dramatically expand the applications of liquid crystal elements.

Ferroelectric liquid crystal materials originated in 1915 from the so-called DOBAMBC, which was synthesized by R18, Meyer et al., J. de Physique, 36.1.
~69 (1975)) Current ferroelectric liquid crystals are characterized by having a chiral smectic C phase (hereinafter abbreviated as Sc* phase), but in DOBAMBG mentioned above, SC
*The temperature range of the phase is as high as 73 to 93°C, making it difficult to use it alone for practical purposes.

It also has a problem in chemical stability because it has a ship base and carbon-carbon double viscosity in the molecule.

From a practical standpoint, ferroelectric liquid crystals are primarily required to have SC* phase appearance and chemical stability over a wide temperature range including room temperature. Recently, attention has been paid to the synthesis of various ferroelectric liquid crystals, ie, ester-based, biphenyl-based, and pyrimidine-based liquid crystals.

However, although the above-mentioned materials have satisfactory chemical stability, it is difficult to obtain a single-composition ferroelectric liquid crystal having a wide temperature range for practical use. Therefore, as in the case of nematic liquid crystals that have already been put into practical use, a method is currently being used for ferroelectric liquid crystals to expand the temperature range of the SC* phase by blending several types of materials. In addition to expanding the temperature range of the SC* phase, blending is also an important method for improving various physical properties, such as pitch, which affects electro-optic response and orientation.

However, at present, the number of types of ferroelectric liquid crystals required for use in blending is very small and insufficient.

(Problems to be Solved by the Invention) A liquid crystal material suitable for blending that is chemically stable and has a wide SC* phase temperature range by solving the chemically unstable problem represented by 0088MBC. The purpose is to provide.

[Structure of the invention] (Means and effects for solving the problems) The liquid crystal material of the present invention is... CI> (In the above formula, n is 1 to 18.1 is Ot, or 1 is an integer, bu is an integer from 1 to 5, hon is an asymmetric carbon atom, the same applies hereinafter)
It is characterized by containing the compound represented by.

The compound represented by the general formula (I>) can be produced by the synthetic route shown below.

u+ @-CN ・・・・・・・・・・・・
...(II)↓IIcbu, C1+30i1 ↓NH3, CHx 0H R20@-CtlO・・・・・・・・・・・・(V)?
■ Phx C1120CH3/KOC (CHx)
3↓ 0”0 R20@-CH・CHQCHt・
・・・・・・・・・・・・ (VI) DC (QC2H5)
s ↓ BF30(C2H!) 2 ↓ H” /If 20 ■ ■ R2 is @CII 2 f CI-C2Hs, ■ C1;3 The optically active alkyl group X represented by 1 to 5 each represents a halogen.

Phenylpyrimidine-based liquid crystals are a powerful compositional component of currently used nematic liquid crystals, and their chemical stability is known to pose no practical problems.
The liquid crystal compound of the present invention represented by ) also has a skeleton structure belonging to the phenylpyrimidine system, and its chemical stability is sufficient for practical use.

Moreover, the temperature range of the Set phase has a wide range of 20 to 60°C. Therefore, when blended in combination with other ferroelectric liquid crystals, it is possible to easily provide a liquid crystal material that can be used practically at room temperature.

The liquid crystal element of the present invention is constructed by sandwiching the liquid crystal material between a pair of parallel substrates, at least one of which is transparent, and is used as a display element for various electro-optical devices.

(Example) Examples of the present invention will be described below.

Example 1 2-(4'-n-octylphenyl)-5-(4'-
Synthesis of (+)-2methylbutoxyphenyl)pyrimidine (A) Synthesis of 4-n-octylbenzamidine After dissolving 0.23 mol of 4-n-octylbenzonitrile in benzene 6011J2 and methanol 65mi2, the mixture was heated at 0°C. The mixture was cooled and dry hydrogen chloride was bubbled in until white crystals were formed. After stirring overnight, the mixture was washed with ether and phosphorus. The obtained 4-n-octylphenylimide ether hydrochloride was 51 g, yield 78%. After adding the above crude product and 80 J of methanol to a 500 n autoclave, 40 g of liquid ammonia was introduced under pressure. After reacting at 80° C. for 24 hours, the temperature was returned to room temperature and ammonia was removed under reduced pressure. The obtained product was separated by P and 46 g of crude 4-n-octylbenzamidine hydrochloride was obtained in a yield of 91%.

(B) Synthesis of 2-(4#-(+)-2-methylbutoxyphenyl)-3-methoxyacrolein 45 g of methoxymethyltriphenylphosphonium chloride was suspended in 250 mi of dehydrated ether and potassium-t
-Butyler) 14.7g were added. To this was added dropwise 23.0 g of (t)-2-methylbutoxybenzaldehyde dissolved in 150 rij2 of dehydrated ether, and the mixture was stirred overnight. This was filtered to remove triphenylphosphine oxide and poured into 400 mi2 of ice water. The ether layer was separated, washed with water, and dried over anhydrous sodium sulfate.

By distilling off the ether, crude 1-(4'-(+
)-2-methylbutoxyphenyl)-2-methoxyethylene was obtained. Purified by vacuum distillation, yield 20g, yield 77
%Met. Ethyl ortho-Ia acid 50G+1J! A mixed solution of 10.1 g of boronic acid trifluoride and 10.1 g of trifluorofluorinated ethyl ether was cooled to 0°C, and 33 g of the above 1-(4-(+)-2-methylbutoxyphenyl)-2-methoxyethylene
Then, after stirring at room temperature overnight, toluene 3001J2 was injected, and 10% sodium bicarbonate water 20011J2 was mixed to separate the toluene layer. After drying with anhydrous sodium sulfate, toluene was distilled off to purify 4- (+)-2.
57.0 g of -methylbutoxyphenyl malonotetraethyl acetal was obtained.

Add 19.0g (0.05 mol) of water to 1211ml of water.
, 12, and 0.051 l of p-toluenesulfonic acid, and the mixture was reacted at 80°C for 3 hours. After cooling to room temperature, 0.52++ sodium bicarbonate was added to neutralize and the product was extracted with ether.

Washed with 10% caustic soda, further washed with water, dried with anhydrous sodium sulfate, and distilled off the ether to give 2-(4-(+) -2-
10.5 g of methylbutoxyphenyl)-3-ethoxyacrolein was obtained in a yield of 80%.

The above A and B, namely 12.8 g (0.05 mol) of 4-n-octylbenzamidine, and 2-(4-(+)
13.1 g (0.05 mol) of -2-methylbutoxyphenyl)-3-ethoxyacrolein was suspended in 120 I of anhydrous methanol, and then suspended in 120 l of anhydrous methanol.
8.1 g was added. This was heated to 50° C. and reacted overnight, and then 20 rg of 6N hydrochloric acid was injected to make it acidic.

The product was extracted with toluene, washed with water, and dried over anhydrous sodium sulfate. After purification with a silica gel column, toluene was distilled off and recrystallized with ethanol at 1001°C. The yield of the crystals obtained was 9.
．． The yield was 42%. This crystalline product was confirmed to be the desired product by the mass spectrum shown in FIG.

Example 2 2-(4-n-octyloxyphenyl)-5-(4
-(+)-Methylbutoxyphenyl)pyrimidine synthesis 2-(4-hydroxyphenyl)-5-(4-(+
)-methylbutoxyphenyl)pyrimidine 5.0g
(0,015 mol) and 3.2 g of octyl bromide in the presence of 251 g of cyclohexanone and 8.3 g of potassium carbonate.
It was refluxed for 0 hours. After distilling off the solvent under reduced pressure, water 100%
rrJ2 was added and extracted with 100 rgfl of toluene. After drying with anhydrous sodium sulfate, it was purified with a silica column and recrystallized with alcohol. The yield of the obtained crystals was 5.3 g.
The yield was 79%.

This crystalline product was confirmed to be the desired product by the mass spectrum shown in FIG.

Examples 3 to 9 Compounds of formula (I) were synthesized in the same manner as in Example 1, except that 11 = 0 or 1, n = 6 to 12, and b = 1.3.5.

Table 1 shows the phase transition temperatures of the compounds obtained in Examples 1 to 9.

As is clear from Table 1, the S
The range temperature of C* phase is 1=0, n=8, (=1 of 18
It has a wide range from ℃ to 60.5℃ with 〇, ro=8, and n=5.

Comparative Examples 1 to 4 Table 2 shows the phase transition temperatures of conventionally known representative ferroelectric liquid crystals with Schiff base-based, biphenyl-based, ester-based, and phenylpyrimidine-based skeleton structures, and the temperature range of the SC* phase. It can be seen that the temperature is about 1 to 20°C, which is narrower than that of the compounds of the above examples.

(Left below) Sc*: chiral smectic C phase, S^: smectic A phase N*: chiral nematic phase, Da: isotropic liquid Example 10 The compounds of Example 5 and Example 8 were mixed in an equimolar ratio. . This mixture exhibited an SC* phase in the temperature range of 100 to 130°C, and showed a phase transition to an isotropic liquid via the SA phase up to 130 to 161°C.

Example 11 The compounds of Comparative Example 2 and Example 5 were mixed at a molar ratio of 2:1. This mixture is S
It was confirmed that C* phase was exhibited. As shown in FIG. 3, this liquid crystal composition is placed on a glass substrate 1.2 with transparent electrodes 3.4
was formed and sandwiched between two transparent electrode substrates whose surfaces had been subjected to rubbing treatment, to create a liquid crystal cell with a liquid crystal thickness of 2 μm. 5 is a sealing material.

When two polarizing plates 6.7 were placed above and below this liquid crystal cell and an electric field was applied while the temperature was maintained at 30° C., two states of display were observed depending on the polarity of the electric field. Response time is 500μs for voltage application of ±10V
It was ec. Further, the contrast was 15:1.

Example 12 The compound of Example 5 and a known material having the following structure were mixed at a molar ratio of 1:3. It was confirmed that this mixture exhibited an SC* phase in the temperature range of 5 to 51°C.

A liquid crystal cell having the same structure as in Example 11 was created using this liquid crystal composition. When two polarizing plates were placed above and below the liquid crystal cell and an electric field was applied while maintaining the temperature at 30°C, it was observed that two states were displayed depending on the polarity of the electric field, as in Example 2. . The response time was 800 μsec for voltage application of ±10 V. The contrast was 1721.

Example 13 The compound of Example 9 was mixed with ferroelectric liquid crystal C5-1013 (trade name, manufactured by Chisso Corporation) 10 times over a fire, and the phase transition temperature was measured, and the results shown below were obtained.

C5-1013: K<OSc*63 SA 7
0 t4* 80 1s.

The above mixture: <OSc Chapter 71 SA 78 G85
Is.

As mentioned above, by using the compound of Example 9,
The temperature range of the Sc zero phase of C5-1013 was expanded by 8°C.

Furthermore, when a cell similar to that in Example 10 was assembled and the response time to voltage application of ±10 V was measured, C5-1
013 alone is 520. uSeC, whereas the above mixture showed a response time of 480 μsec, which was a 40 μsec reduction in response time. This is considered to be due to the low rotational viscosity of the phenylpyrimidine material.

Furthermore, the above-mentioned mixture had excellent orientation properties, making it possible to form monodomains over the entire orientation region.

[Effect of the invention] As is clear from the above examples, the liquid crystal material of the present invention has the following properties:
It is effective as a component for chiral smectic liquid crystal compositions over a wide temperature range including room temperature.

Therefore, the liquid crystal element of the present invention can be widely used as a display device for electro-optical equipment.

[Brief explanation of the drawing]

Figure 1 shows the mass spectrum of the liquid crystal compound of Example 1, and Figure 2 shows the mass spectrum of the liquid crystal compound of Example 1.
The figure shows a mass spectrum of the liquid crystal compound of Example 2, and FIG. 3 is a cross-sectional view showing the structure of a liquid crystal element. 1.2...Glass substrate 3.4...Transparent electrode 5...Sealing material 6.7.・
...Polarizing plate applicant Toshiba Corporation Agent Patent attorney Satoshi Suyama - 1st Seki

Claims (2)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the above formula, n is an integer of 1 to 18, m is an integer of 0 or 1, l is 1
An integer of ~5, * indicates an asymmetric carbon atom. same as below. ) A liquid crystal material consisting of a compound represented by (2) A liquid crystal element characterized by sandwiching a liquid crystal material containing a compound represented by the general formula ▲numerical formula, chemical formula, table, etc.▼ between a pair of substrates, at least one of which is transparent.