JPH0482853A - Tolane-type tricyclic alkylene glycol derivative - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (R<1> and R<2> are 1-7C n-alkyl; n is 1-7 ; group of formula IV is cyclohexane ring having trans configuration). EXAMPLE:The compound of formula V. USE:A component of nematic liquid crystal composition. It is a liquid crystal compound having perpendicular orientation property and capable of increasing a pretilt angle of a conventional nematic liquid crystal composition by mixing with the nematic liquid crystal composition and sealing in a liquid crystal display cell having an oriented membrane forming a pretilt angle of about 5 deg.. It is useful as a material for super-twisted nematic liquid crystal display device. PREPARATION:The objective compound of formula I can be produced by reacting a compound of formula II with a compound of formula III in a solvent (e.g. N,N-dimethylformamide) in the presence of a base (e.g. diethylamine) using dichloro-bis(triphenyl-phosphine)palladium(II) and cuprous iodide as catalysts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to tolan-based 3 which is useful as an electro-optical display material.
The present invention relates to cyclic alkylene glycol derivatives, liquid crystal compositions containing these compounds, and liquid crystal display devices.

[Conventional technology]

A typical liquid crystal display cell is a TN-LCD (twisted nematic liquid crystal display), which is used in watches, calculators, electronic notebooks, pocket computers, word processors, personal computers, and the like. In recent years, the amount of information displayed on a single screen has increased with the increase in information processed by OA equipment. Conventional TN-LCDs are particularly suited for high-end applications such as word processors and personal computers in terms of display quality such as contrast and viewing angle. It is no longer possible to meet the demands of time-division driving.

In this situation, Scheffer (5cheffer)
etc. [SID '85 Digest, P120 (
1985)] or for Kinugawa [SID '86 Di
gest, PL22 (1986)) by STN
(Super Twisted Nematic) LCD was developed and is beginning to become widespread as a display for high information processing applications such as word processors and personal computers.

[Problem to be solved by the invention]

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.

For orientation, a method is known in which the pretilt angle is controlled to a high tilt angle of about 20' by oblique vapor deposition of SiOx. A method is known in which the pretilt angle is controlled to about 5° by rubbing an organic film such as the above. In addition, various organic films have been developed and are used by controlling the pretilt angle to 5 to 10 degrees by a rubbing method. It is known that the higher the pretilt angle, the less likely stripe 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.

The problem to be solved by the present invention is to provide novel vertically aligned liquid crystal compounds, and to make it possible to create a practically stable alignment film by rubbing nematic liquid crystal compositions containing these compounds with a rubbing method. A 5TN-LCD that can form a pretilt angle higher than 5° by encapsulating it in a liquid crystal display cell with a pretilt angle of about 5°.
The purpose is to create.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention has been developed by the general formula (I) (wherein R1 and R2 each independently represent a straight-chain alkyl group having 1 to 7 carbon atoms, and n is an integer of 1 to 7 carbon atoms. (representing a bovine ring) is provided.

The compound represented by general formula (1) according to the present invention can be produced according to the following production method.

The compound of formula (m) is reacted with the compound of formula (m) in the presence of N,N-dimethylformamide in a solvent such as N,N-dimethylformamide using cyclolobis(triphenylphosphine)palladium(II) and cuprous iodide as a catalyst. A compound of formula (I) is prepared.

Table 1 lists the transition temperatures of typical compounds represented by the general formula (I) according to the present invention thus produced.

... (I) Each represents the same thing as in general formula (I). ) Formula (I
T) compound with a base such as diethylamine (in the table, C represents a crystalline phase, S represents a smectic phase, N represents a nematic phase, and ■ represents an isotropic liquid phase) according to the general formula (1).
Preferred representative examples of liquid crystal compounds that can be used in combination with the compound represented by are, for example, 4-substituted benzoic acid 4'-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4'-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4'-substituted biphenyl ester, 4-(4-substituted cyclohexanecarbonyloxy)benzoic acid 4'-substituted phenyl ester, 4-(4-substituted cyclohexyl)benzoic acid 4'-substituted phenyl ester, 4 -(li-substituted cyclohexylbenzoic acid 4'-substituted cyclohexyl ester, 4-substituted 4'-substituted biphenyl, 4-substituted phenyl-4'-i-substituted cyclohexyl ester, 4-
Substituted 4"-substituted terphenyl, 4-ffil biphenyl 4'-substituted cyclohexane, 2-(4-i substituted phenyl)
-5-substituted pyrimidine and the like can be mentioned.

Table 2 shows that a mixed liquid crystal consisting of 80 Mm% of mixed liquid crystal (A), which is currently widely used as a nematic liquid crystal material, and 20i mass% of N (11) of formula (1) is assumed to form a pretilt angle of approximately 5°. Nissan Chemical's "Sunever 15"
The alignment film prepared by rubbing the organic film of 0" was placed vertically in parallel and sealed in a combined liquid crystal display cell, and the pretilt angle measured by magnetic field potential method was displayed. For comparison, mixed liquid crystal (A) 5TN- which has a similar structure to itself and 80% by weight of the mixed liquid crystal (A) and the compound represented by the general formula (I).
20% by weight of compound (a) having excellent properties for LCD
The pretilt angle of a mixed liquid crystal encapsulated in the same manner is shown.

In addition, the mixed liquid crystal (A) 20% by weight 16% by weight 6% by weight 8% by weight 8% by weight 8% by weight 8% by weight 8% by weight as well as 8% by weight It consists of Its physical properties are as follows.

=9= N-I transition temperature Viscosity (20°C) Anisotropy of refractive index (Δn) threshold voltage Furthermore, compound (a) has the formula It is a compound represented by

Part 2 table 54.5 °C 21, Oc, p.

0.0917 1.60V From the data posted in Table 2, the compound represented by general formula (I) increases the pretilt angle of the mixed liquid crystal by 1 degree or more, and the compound represented by general formula (I) Mixed liquid crystal is 5T
It can be seen that a pretilt angle that is 1° or more higher than that of the mixed liquid crystal containing the structurally similar compound (a) useful for N-LCDs is understood. A difference in pretilt angle of 1° makes it difficult for stripe domains to occur significantly, improving the yield during manufacturing of liquid crystal display cells. Furthermore, it was confirmed that the compound represented by the general formula (1) has uniform vertical alignment on the glass surface in a nematic state.

The compound of the present invention is characterized by increasing the pretilt angle when a normal liquid crystal is sealed, and is not limited to liquid crystal display cells having a pretilt angle of about 5°. Further, the vertically aligned liquid crystal compound of the present invention is extremely useful for the vertical alignment required in, for example, an ECB (birefringence control) type display device.

〔Example〕

Example 1 mol) was added to a mixed solvent of 50 ml of N,N-dimethylformamide and 20 ml of diethylamine, and dichloro-
Bis(triphenylphosphine)palladium 0.21g
(0,0003 mol) and cuprous iodide 0.65 g
(0,003 mol) was added dropwise under stirring at room temperature, followed by dropwise addition of 16 wt % mol), followed by reaction at room temperature for 8 hours.

After the reaction was completed, the reaction mixture was added to water-hydrochloric acid, stirred for 15 minutes, and then extracted three times with 100 ml of ethyl acetate.

The extract was washed with water, dried, and the solvent was distilled off under reduced pressure. The resulting residue was purified by recrystallization from 170 ml of ethanol to obtain 7.8 g (0.02 mol) of the following compound.

12.8 wt% 12.8 wt% 6.4 wt% Example 2 20 wt% Transition temperature below room temperature (C-)S) 145°C (srN) 163°C (N2I) 6. A mixed liquid crystal consisting of 4% by weight, 6.4% by weight, 6.4% by weight, and 6.4% by weight was prepared, and the physical properties were measured, and the results were as follows.

N-I transition temperature 78.7℃ Viscosity (20
'C) 22.9 c,p Anisotropy of refractive index (Δn) 0.122 Dielectric anisotropy (Δε
) 6.5 Threshold voltage (V ) 1.93 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 6.5°. Ta.

〔Effect of the invention〕

The compound represented by the general formula (I) according to the present invention has vertical alignment property by itself, and when a nematic liquid crystal composition containing it is mixed with a normal nematic liquid crystal composition, By enclosing the liquid crystal display cell in a liquid crystal display cell having an interlayer film that forms a pretilt angle of approximately 5 degrees,
This allows the pretilt angle to be increased.

Therefore, the compound represented by the general formula (I) according to the present invention is extremely useful as a material for 5TN-LCD.

Agent: Patent Attorney Katsutoshi Takahashi

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R^1 and R^2 each independently represent 1 to 1 carbon atom.
7 represents a linear alkyl group, n represents an integer from 1 to 7, ▲ includes numerical formulas, chemical formulas, tables, etc. ▼ represents a cyclohexane ring in trans configuration. ) A compound represented by 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. 4. A liquid crystal display device, characterized in that the nematic liquid crystal composition according to claim 2 is vertically aligned.