JPH032137A - Tolan-based alkylene glycol derivative - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I (R<1> is 1-7C straight-chain alkyl: R<2> is 1-3C straight chain alkyl; n is 1-5). EXAMPLE:A compound expressed by formula II. USE:An electrooptical display material and nematic liquid crystal composition, utilizable in super.twisted.nematic liquid crystal display devices (STN-LCD) and capable of preparing the STN-LCD having a higher pretilted angle than 5 deg. by mixing with a matrix liquid crystal. PREPARATION:A compound expressed by formula III is reacted with a compound expressed by formula IV in the presence of a strong base, such as potassium tert-butoxide, in a polar solvent, such as dimethyl sulfoxide, to afford the compound expressed by formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to tolan-based alkylene glycol derivatives useful as electro-optical display materials, liquid crystal compositions containing these compounds, and liquid crystal display devices.

[Conventional technology]

Typical liquid crystal display cells include TN-LCD (twisted nematic liquid crystal display), watches, calculators,
Electronic notebook, pocket converter, word processor,
Used in non-sonal computers, etc. In recent years, the amount of information displayed on a single screen has increased with the increase in information processed by OA equipment, and conventional TN-LCDs have been used particularly for word processors and personal computers due to display quality such as contrast and viewing angle. It is no longer possible to meet the demands for high time division drive such as

In this situation, Scheffer (r of 5cheff)
etc. [SID'85 Digest, P120 (19
85)] or CSID'86 Dig@st for Kinugawa
P122 (1986) ) tic by STN (
Suitcouple twisted nematic)-LCDs have been developed and are beginning to be widely used as displays for high information processing applications such as word processors and nocusonal combinators.

In a 5TN-LCD, control of the angle between the alignment plane and the liquid crystal molecules, that is, the pretilt angle, is an important factor that greatly affects the yield and the like in manufacturing the liquid crystal display cell.

As an orientation method, a method is known in which the pretilt angle is controlled to a high tilt angle of about 20° by oblique evaporation of SiO. A method is known in which the pretilt angle is controlled to about 5° by rubbing the organic film.

In addition, various organic films have been developed and used by controlling the pretilt angle to 5 to 10'' using a rubbing method.

It is known that the higher the pretilt angle, the less likely striped domains will occur and the better the yield during the production of liquid crystal display cells. The current situation is that it is extremely difficult to create a stable alignment film.

[Problem to be solved by the invention] Under these circumstances, the inventors filed Japanese Patent Application No. 1-46656.
In the formula [R1 and R2 each independently represent a linear alkyl group. ] The liquid crystal compound represented by has vertical alignment, and 5TN-
It has been found that this method has the effect of increasing the pretilt angle of an LCD.

However, due to the constraints of producing a practical liquid crystal that exhibits a nematic phase at room temperature, the compound of formula (I) can only be contained in a maximum of about 30% in the parent liquid crystal that is currently widely used as a nematic liquid crystal material. However, as a result, the obtained mixed liquid crystal did not exhibit vertical alignment.

The problem to be solved by the present invention is to create a practically stable alignment film using a rubbing method in terms of quality by mixing the compound of formula (T) with a host liquid crystal that is currently widely used as a nematic liquid crystal material. Approximately 5°
Provides a compound capable of forming a pretilt angle higher than 5° by encapsulating it in a liquid crystal display cell with a pretilt angle of 5T having a pretilt angle higher than 5°.
The objective is to create an N-LCD.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides - formation (in the formula,
R1 represents a linear alkyl group having 1 to 7 carbon atoms,
R2 represents a linear alkyl group having 1 to 3 carbon atoms,
n represents an integer of 1 to 5, and a compound represented by f is provided.

The compound of formula (2) according to the present invention can be produced according to the following production method.

(In the above reaction formula, R1 and R2 each represent the same thing as in the above formula (n).) The compound of formula (g) is dissolved in a polar solvent such as potassium t-butoxide such as potassium t-butoxide. A compound of formula ([1)] is produced by reacting K with a compound of formula □□□ in the presence of a strong base.

Table 1 lists the transition temperatures of representative compounds (2G) according to the present invention thus produced.

/ Totsu Table 1 (In the table, C represents a crystalline phase, N represents a nematic phase, and ■ represents an isotropic liquid phase.) Liquid crystal compounds that can be used in combination with the compound of formula (n) Preferred representative examples include, for example, 4-substituted benzoic acid 4'-substituted phenyl ester, 4-substituted cyclohexane carbon e4'-8m phenyl ester, 4-[substituted cyclohexane carbon? 4'-substituted phenyloxybenzoic acid ester, 4-(4-ft-substituted cyclohexanecarbonyloxybenzoic acid 4'-substituted phenyl ester, 4-(4-R
(substituted cyclohexyl) benzoic e 4'-a substituted phenyl ester, 4-(4-substituted cyclohexyl)benzoic acid 4
'-Substituted cyclohexyl ester, 4-fitfi4'
-f-substituted phenyl, 4-tat-substituted phenyl-4'-substituted cyclohexane, 4-substituted 4"-substituted terphenyl, 4
-substituted piphenyl 4'-file cyclohexane, 2-
Examples include (4-fEi-substituted phenyl)-5-substituted pyrimidine.

Table 2 shows 60% by weight of the base liquid crystal (A), which is currently widely used as a nematic liquid crystal material, and the following compound of formula (I) (
A mixed liquid crystal consisting of 10% by weight of the compound (b) below, 10% by weight of the compound of formula (II) and 10% by weight of the compound of formula (II) was heated at an angle of about 5°. Sunever 150 manufactured by Nikki Kagaku, which is said to form a pre-tilt angle.
The alignment film made by rubbing the organic film of For the mother liquid crystal solid itself and the mother liquid crystal hole 6
0 wt. 1
The pretilt angle and Δn of a mixed liquid crystal containing 01f% sealed in the same manner are shown.

In addition, the mother liquid crystal hole is as well as Its physical properties are as follows.

N-I transition temperature 54.5℃ Viscosity (20℃) 21. Oe, p.

Anisotropy of refractive index (Δn) 0.0917 Anisotropy of dielectric constant (3g) 6.5 Threshold voltage 1.60V Furthermore, compounds (a), (b), ((ri and (d)
) have the chemical structural formulas shown below.

Table 2 From the data posted in Table 2, it can be seen that the mixed liquid crystal containing compound (a) and compound (b) both have a pretilt angle of 1.
It is clear that the degree of increase is greater in the mixed liquid crystal containing the compounds A1 and M2 of the present invention than in the mixed liquid crystal containing the structurally similar compound (C) and compound (d). be.

Furthermore, it can be understood that the compound of the present invention also has the effect of increasing Δn of nematic 1, a parent liquid crystal material currently widely used as a liquid crystal material.

〔Example〕

(0,040 mol) of trimethyl sulfoxide 100-
Potassium-t-butoxa()' 5.6 was dissolved in a mixed solvent of 25 and tetrahydrofuran and stirred at room temperature.
,! i' (0,050 mol) was added and stirring continued for 30 minutes. This mixture is then given the formula C2CH2CH2oc
Compound 4.6 of H3,! 9 (0,050 mol) was added thereto, and the mixture was reacted at 60°C for 3 hours.

After the reaction was completed, 150ml of 9% hydrochloric acid was added to the reaction mixture, followed by extraction three times with 100ml of ethyl acetate.

After washing the extract with water and drying with anhydrous sulfuric acid, the solvent was distilled off under reduced pressure and the resulting residue was diluted with ethanol 12
Recrystallize from 0 m and purify to obtain the following compound 9.79 (
0,033 mol) was obtained.

Transition temperature 68°C (C-+N) 69°C (Ng engineering) Example 2 The following compound was obtained in the same manner as in Example 1 except that 10.6.9 (0,040-R) was used as the compound. .

Transition temperature 60°C (C-+N) 68°C (NxI) Example 3 As a result of creating a mixed liquid crystal and measuring its physical properties,
It was as follows.

N-I transition temperature 79.4°C Viscosity (20°C) 29.3 e, ps Anisotropy of refractive index (Δn) 0.132 Anisotropy of dielectric constant (Δε) 5.5 Threshold voltage 2. 20V The pretilt angle was measured in an antiparallel liquid crystal display cell prepared by rubbing this mixed liquid crystal with "Sunever 150" and found to be 6.7°.

〔Effect of the invention〕

The compound of the formula (ID) according to the present invention is
By mixing K with the compound of formula (1) related to No. This increases the pretilt angle of the liquid crystal, and the degree of increase is greater than when using a mixed liquid crystal containing a compound having a structure similar to the compound of formula (10) and a compound of formula (1).

Therefore, the compound of formula (IT) according to the present invention is 5TN
- Extremely useful for making LCDs.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R^1 represents a linear alkyl group having 1 to 7 carbon atoms, and R^2 represents the number of carbon atoms. 1 to 3 linear alkyl groups, n represents an integer of 1 to 5). 2. A nematic liquid crystal composition containing the compound according to claim 1. 3. A super twisted nematic liquid crystal display device using the nematic liquid crystal composition according to claim 2.