JPH01245089A - Liquid crystal material - Google Patents

Abstract

PURPOSE:To provide a ferroelectric liquid crystal compound consisting of 4-[P-(R or S)-2-octyloxyphenyl]oxycarbonyl-4'-alkoxytolane and useful as a display element having excellent image display response. CONSTITUTION:The objective liquid crystal compound is expressed by formula II (R is 5-15C alkyl; * is asymmetric carbon) and is produced by using a phenol compound having optically active group and expressed by formula I, etc., as a production raw material. The objective compound has broad temperature range of chiral smectic C phase or H phase and high spontaneous polarization value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ferroelectric liquid crystal compound useful as a display element with excellent responsiveness for displaying a single image, and a chiral smectic liquid crystal composition containing the same.

Currently, display elements using liquid crystal materials are of a light-receiving type, and have the advantage of low power consumption and the ability to create thin display devices, and are in widespread practical use. On the other hand, EL (electroluminescence) and plasma displays, which are light-emitting display systems and feature high-speed response, are being actively developed.

[Conventional technology]

Most of the liquid crystals that have been used in display devices so far have been nematic liquid crystals, and the mainstream is TN (twisted nematic).
Twistd Nematic ) ] type. Although this TN type display system has advantages such as small size and low power consumption, it also has the disadvantage of slow response speed when displaying zero images. Various attempts have been made to improve this point, but Molecular Crystals and Liquid Crystals
Liquid Crystals) Volume 94 M155
The results demonstrate the theoretical limits shown on pages 165 to 165.

It appears that the development of materials for TN type displays has almost reached its limit.

Therefore, in order to overcome the above-mentioned drawbacks, interest has shifted to the development of chiral liquid crystals in place of nematic liquid crystals in recent years, and in particular, significant progress has been made in ferroelectric liquid crystals.

What was the first ferroelectric liquid crystal developed?

H3 -CH2♀HC2H.

(In the formula, * indicates an asymmetric carbon atom)
(hereinafter abbreviated as DOBAMBC), its liquid crystal phase series and phase transition temperature (° C.) are as follows.

(In the formula, C is a crystalline phase, SA is a smectic A phase, Sc
” indicates chiral smectic C phase, SH* indicates chiral smectic H phase, and ■ indicates isotropic liquid.)

Ferroelectricity is expressed in chiral smectic C phase (hereinafter abbreviated as Sc*) or chiral smectic H phase (hereinafter abbreviated as SH*), which are classified and named based on molecular arrangement.3The response based on ferroelectricity is expressed by the following formula (A ) τ=Tsu, ECλ] (In the formula, τ is the response time, η is the viscosity of the liquid crystal material, PS is spontaneous polarization, and E is the electric field.) Therefore, a display element that can theoretically respond up to 1 μs can be obtained. This possibility was proposed by R.B. Meyer and others in the Journal of Physics France (Jou
rnal of physics france)
Volume 36, page 69 (1975).

[Problem that the invention seeks to solve]

There are compounds shown in Table 1 as typical ferroelectric liquid crystals. However, these compounds undergo isomerization within a short time when exposed to light, are unstable to moisture, and lose liquid crystallinity due to hydrolysis reactions, making them undesirable as materials for display elements. .

Recently, ferroelectric liquid crystal compounds shown in Table 2 have been disclosed.

Table 2 In Table 2, R and R' represent an alkyl group, and * represents an asymmetric carbon atom.

Although these compounds solve the above problems and exhibit relatively large values of spontaneous polarization (Ps), they are not practical due to the narrow temperature range of the kyphrusmectic phase exhibiting ferroelectricity.

[Failure to solve the problem]

The present inventors have conducted intensive research from the above viewpoint.

The present invention has been accomplished by discovering a ferroelectric liquid crystal compound that has excellent stability, a wide temperature range that belongs to the S♂ phase or S)1* phase, and a large Ps value, and a liquid crystal composition containing the same. It was.

That is, the present invention provides a liquid crystal having a tolan skeleton represented by the general formula [''I] (wherein R represents an alkyl group having 5 to 15 carbon atoms, and * represents an asymmetric carbon atom). It is a sexual compound.

The present invention also provides a liquid crystal composition containing at least one compound represented by the above general formula CD.

In general formula [I], the tolan skeleton is named as follows.

Therefore, the compound represented by the above general formula [■] is
It can be named 4-(p-(R or 5)-2-octyloxyphenyl)oxycarbonyl-4'-alkoxytran.

The method for producing the compound represented by the general formula CI) will be described in detail below, and a pheno-μ compound having an optically active group is used as one of the raw materials for production. It can be synthesized by the method described in Flo 1-22051, and can also be obtained from Teikoku Kagaku Sangyo Hashira.

An outline of the method for producing the compound of the present invention is shown by the following formula.

CH3 CH, CH, [B] CI) (In the above formula, R is an alkyl group having 5 to 15 carbon atoms, * is an asymmetric carbon atom, and TEA is triethylamine.

THF represents tetrahydrofuran. ) [made by
] The compound of the present invention exhibits the following actions and features.

First, a group that can be easily decomposed in an atmosphere containing moisture, a group that does not have an azomethine group (-N=CH-) and that is isomerized by light.

It is very stable. Next, the compound of the present invention exhibits ferroelectricity even if it is used alone in a wide temperature range.
For example, it is possible to lower the lower limit of the temperature range exhibiting 91 ferroelectricity to below room temperature by mixing Este/V type, bipheni ρ type, pyrimidine type, etc.

Furthermore, the Ps (spontaneous polarization) value of the compound of the present invention is 40 nCA
Due to the large size, when used as a blend material in a mixed system, it is possible to achieve the purpose of lowering the melting point and to increase the Ps of the mixed system.
It is possible to improve the value.

〔Example〕

The present invention will be explained below by way of examples.

% in the examples indicates weight %.

Production Example 1 Synthesis of 4-alkoxyphenylacetylene CB) In a 500 cc three-meter flask equipped with a stirrer, a thermometer, and a reflux condenser, 0.234 mol of 4-alkoxybromobenzene and 3-mefiV-1- were placed in a nitrogen stream. border
-3-all 29.57t (0
, 852 mol), triphenylphosphine 1.0 (1, dichlorobis(triphenyl-phosphine) palladium catalyst 0.52 f (0.73) was dissolved with stirring, and 160 rIIy of copper iodide was added. After stirring at room temperature for 3 hours, Gradual heating was carried out to bring the internal temperature to 90°C over 30 minutes.The reaction was carried out at this temperature for 20 hours.After the reaction, the temperature was returned to room temperature, triethylamine was distilled off under reduced pressure, and Ezo/
300 ml was added, washed with water, and dried over anhydrous sodium sulfate. After t6, the ether was distilled off, and the residue was subjected to silica gel column chromatography (200 Messier silicage #400F, developing solvent: benzene) to obtain a compound of the linear formula as an intermediate compound.

In a 300 cc Mitsuro flask equipped with a stirrer, a thermometer, and a distillation device, 58.4% of the above intermediate compound was added in a nitrogen stream.
120 mt of anhydrous toluene and 310 μm of sodium hydride (60% Nudur dispersant) were charged, and the mixture was stirred at room temperature for 30 minutes. The mixture was gradually heated to reach an internal temperature of 70° C. over 30 minutes. Acetone (a by-product) began to reflux and distill out together with toluene, but the reaction continued with further heating until the distillation temperature reached the boiling point of toluene.

This took 2 hours, and the amount of solvent distilled out was 60 ml. After the reaction is complete, return to room temperature and add benzene 100m! In addition, it was washed with water and dried with anhydrous sodium sulfate. After evaluation, the organic solvent was distilled off.

The residue was subjected to silica gel column chromatography (200
Mesh silica gel 150f, developing solvent: hexane) K. 4-Alkoxyphenylacetylene shown in Table 3 was obtained in a yield of 85 to 95%. Its structure is IR
and confirmed by NMR spectrum.

The results are shown in Table 3.

flu production example 2 p-(2-octyloxy)phenyl - 100cc equipped with stirrer, thermometer and reflux condenser
In a Mitsuro flask, add p-((s)-2-octyμoxy)pheno-/L/(manufactured by Teikoku Kagaku Sangyo Co., Ltd.) 3.00 f
(13.5 mmol) and 20 ml of anhydrous pyridine were charged and dissolved under stirring. To this pyridine solution was added 3.26 f of 4-bromobency N chloride (149 mm
20 ml of a tetrahydrofuran solution containing 20 ml of tetrahydrofuran was added under water cooling. After returning the reaction temperature to room temperature, it is brought to reflux temperature,
Stirred for 8 hours.

After the reaction was completed, ether was added, and the mixture was washed with water, alkaline water with 10% caustic soda, and water in this order, and then dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was isolated and purified by silica gel column chromatography (200 mesh silica gel IV 100 f, developing solvent: hexane-benzene gradient) to give a solution with a melting point of 71.4-7.
p-(2-octyloxy)phenylene/with a temperature of 2.3°C
L/-4-7'' lomobenzoate [C] was obtained with a yield of 98%.

The data of this compound was as follows.

IR, vffi, x 2932. 1728. 1
506° 1250° 1204, 1082. 748
cm-"NMR: δ'3 7.8 (Q, 4H)
, 6.9(q, 4H).

48 (m, IH), 1.8-0.7 (m, 16
H) Into a Mitsuro flask equipped with a ppfil stirrer, a thermometer and a reflux condenser, the p obtained in Production Example 2 was added in a nitrogen stream.
-(2-octyloxy)pheny/L'-4-bromobenzony) 5 mmol, 4- obtained in Production Example 1
Alkoxyphenylacetylene 5.5 mmol,
) 100 m mo of phosphine, dichlorobis(triphenylphosphine) palladium catalyst 60119, and 60 ml of hydrethylamine were charged, stirred and dissolved, and copper iodide 619 was added. After stirring at room temperature for 2 hours, the mixture was gradually heated to bring the internal temperature to 70°C over 30 minutes.

The reaction was allowed to proceed at this temperature for 8 hours. After the reaction, return to room temperature.

Triethylamine was distilled off under reduced pressure, and the residue was diluted with ether/'
100 yd was added thereto, washed with water, and dried over anhydrous sodium sulfate. After filtration, the ether was distilled off, and the residue was subjected to silica gel column chromatography (200 mesh silicage/v100?, developing solvent benzene:hexane = 1:1).
) and isolated and purified. Recrystallize with hexane 4
-(p-2-octyloxyphenyl)oxycarponi/L/-4'-alkoxytran [■] 81-94%
It was obtained in a yield of . The structure of each compound was confirmed using IR and NMR spectrum data.

Example [Compound 5] IR: v prefecture: ”” 2920.2216.173
6.1248.762 cm ”NMR:δ!i'Kon3
8.2-6.8 (m, 12H), 43 (m, IH).

4.0 (t, 2H), 2.0~0.6 (m,
Table 4 shows the results along with the phase transition temperature of each compound obtained.

Example 2 Compounds NQ2.3 and 400 shown in Table 4 Liquid crystal compositions shown in Table 5 below were prepared using the liquid crystal compounds of the present invention, and the phase transition temperatures thereof were measured, as shown in Table 5. there were.

Table 5 When this liquid crystal composition was coated with a polyimide film and subjected to parallel alignment treatment by rubbing one surface, and injected into a cell having a transparent electrode with a cell thickness controlled to 2 μm, uniform alignment was observed at Sc*. Seven μ was obtained.

Furthermore, when a square wave voltage of ±10 V is applied at a temperature of 78°C, the response time is 0.69m5. A display element with a contrast of 10 was obtained.

Example 3 A liquid crystal composition consisting of 80% of the liquid crystal composition of Example 2 and 20% of the compound represented by the following structural formula was prepared, and its phase transition temperature was measured and found to be as follows.

25℃ 28℃ 77℃ 110℃ 115℃C-→
Sx-→S♂-→SA-→Ch-→I When this liquid crystal composition was injected into a cell similar to the cell used in Example 2, S
A uniformly oriented cell could be obtained with C*. Response time of this cell at 30°C: 1.3 ms, contrast: 1
It was 3. It was also possible to lower the melting point and expand the temperature range of Sc* by mixing it with biphenyl-based, pyrimidine-based liquid crystal compounds, etc. in addition to Nether-based materials.

〔Effect of the invention〕

As shown in Example 1 above, one compound of the present invention is S
It is a compound exhibiting a c* phase and having 1 ferroelectricity, and from the results of Examples 2 and 3, it is clear that it is an effective component in obtaining chiral smectic liquid crystal compositions over a wide temperature range including room temperature. It is.

Such effects are achieved for the first time by the present invention.

Claims (2)

[Claims] (1) General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ [I] (In the formula, R represents an alkyl group having 5 to 15 carbon atoms, and * represents an asymmetric carbon atom). A liquid crystal compound characterized by having a skeleton. (2) General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ [I] (In the formula, R represents an alkyl group having 5 to 15 carbon atoms, and * represents an asymmetric carbon atom). A liquid crystal composition comprising at least one liquid crystal compound having a skeleton.