JPS5933566B2 - 1,4-di-(cyclohexylethyl)biphenyl derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel nematic liquid crystal compounds of die-tilbiphenyl derivatives useful as electro-optic display materials.

The novel nematic liquid crystal provided by the present invention has the general formula R1□CH2, CH2□CH2CH2□R2 (I), where R and R2 each represent a linear alkyl group having 1 to 7 carbon atoms.

] 1-(trans(ecatria-ecatrianole)-4'-n-anolequinolecyclohexynolethyl}-4-(trans(ecatria-equatorial)-4''-n-alkylcyclohexylethyl)biphenyl It is.

A typical type of liquid crystal display cell is M-Shut (M-
Schadt) etc. [APPL1EDPHY51C5LE
TTER518127-128 (1971)]
Mode Cell) or G.H. Heilmayer (G.
-H Heilmeier) etc. [PROCEEDINGO
FTHE Engineering, E, E, E.

1162-1171 (1968)].
Mode Cell) or G.H. Heilmeyer (G.
-HH Heilmeier) etc. [APPLIEDPHYS
ICSLETTERS 13, 91 (1968)] or DLNVhite etc. [J
OURNALOFAPPLIEDPHYSICS45,
4718 (1974)]. The liquid crystal materials used in these liquid crystal display cells are required to have various properties, but having a nematic phase over a wide temperature range including room temperature is an important property that is commonly required for all types of display cells. .

Most of the materials that can be used for practical purposes with such properties are usually obtained by mixing several or more components, which consist of a compound that has a nematic phase near room temperature and a compound that has a nematic phase above room temperature. It is then prepared. Many of the above mixed liquid crystals currently in practical use are required to have a nematic phase over the entire temperature range of at least -30°C to +65°C. In order to meet such requirements, 4,41-monosubstituted terphenyl,
Crystal phase mononematic phase transition temperature (C-N
Compounds having a nematic phase monoisotropic liquid phase transition temperature (N-1 point) of about 200 DEG C. are often used. However, these compounds have the undesirable property of increasing the viscosity of the resulting mixed liquid crystal, thereby decreasing the response speed. The compound of formula (1) according to the present invention is a novel compound with improved properties.

That is, when preparing a practically usable mixed liquid crystal having an N-1 point of 65°C or higher by mixing it with one or more other nematic liquid crystal compounds, in many cases, the above-mentioned known liquid crystal compound is mixed with the above-mentioned known liquid crystal compound. In comparison, the increase in viscosity of the mixed liquid crystal can be suppressed to a much smaller extent. The compound of formula (1) according to the present invention can be produced, for example, according to the following production method.

Step 1 - ① A compound of formula () is prepared by reacting biphenyl with anhydrous aluminum chloride in chichichloride or nitrobenzene.

Second Step - The compound of formula () produced in the first step is reacted with hydrazine and potassium hydroxide in diethylene glycol or triethylene glycol to produce the compound of formula ().

Step 3 - A compound of formula (V) is produced by reacting the compound of formula () produced in the second step with anhydrous aluminum chloride in carbon disulfide or nitrobenzene. Step 1 The compound of formula (V) produced in step 3 is reacted with hydrazine and potassium hydroxide in diethylene glycol or triethylene glycol to produce the compound of formula (1).

The transition temperature of the compound of formula (1) thus produced is
Listed in the table. The compound of formula (1) according to the present invention is a nematic liquid crystal compound having a weak negative dielectric anisotropy, and therefore can be used, for example, with other nematic liquid crystal compounds having a negative or weak positive dielectric anisotropy. It can be used as a material for dynamic light scattering display cells in a mixture state, and as a material for field effect display cells in a mixture state with other nematic liquid crystal compounds with strong positive dielectric constant anisotropy. can be used.

As described above, preferred representative examples that can be used in combination with the compound of formula (1) include 4.4'' monosubstituted benzoic acid phenyl ester, 4.4' monosubstituted cyclohexanecarboxylic acid phenyl ester, etc. ester, 4,4' monosubstituted cyclohexanecarboxylic acid biphenyl ester, 4(4
Monosubstituted cyclohexanecarbonyloxy)benzoic acid 4'
Monosubstituted phenyl ester 4 (4-substituted cyclohexyl)
Benzoic acid 4' monosubstituted phenyl ester, 4(4-substituted cyclohexyl)benzoic acid 4' monosubstituted cyclohexyl ester, 4,4'-biphenyl, 4,4'=phenylcyclohexane, 4,4' monosubstituted terphenyl, 4・4'-
Biphenylcyclohexane, 2 (4' monosubstituted phenyl)
Examples include 5-substituted pyrimidine.

Table 2 shows matrix liquid crystals (90% by weight of Al and compounds of formula (I) shown in Table 1, 1, /F6.2,
J. 3, /F6.4, /V). 5, 10% by weight of each of
The N-I point and viscosity measured for each mixed liquid crystal consisting of are shown, and for comparison, the N-I point and viscosity measured for the base liquid crystal (A itself) are shown.

In addition, there is a mother liquid crystal.

From the data posted in Table 2, the four compounds of formula (I) are:
N of the mixed liquid crystal without increasing the viscosity of the mixed liquid crystal.
-You can understand that it increases the score.

The viscosity value of about 22 centipoise/20 DEG C. in Table 2 is considerably lower than the viscosity values of various mixed liquid crystals having an N-1 point of 65 DEG C. or higher, which is at the current average practical level. The practical value of the compound of formula (1) lies in the fact that mixed liquid crystals with such low viscosity can be obtained. The effects of the present invention are also clarified by the following comparative experiments.

A known compound of the formula whose chemical structure is similar to the compound of formula (1) according to the present invention and which is used for the purpose of increasing the N-1 point of the mixed liquid crystal is added to the above-mentioned parent liquid crystal in various proportions. Mixed.

Similarly, one of the compounds according to the invention, ie a compound of the formula, was mixed into the parent liquid crystal (A) in various proportions.

Regarding the two types of mixed liquid crystals obtained in this way, my husband's N
- point and viscosity were measured. Based on these measurement results, Figure 1 of the attached drawings shows the relationship between the N-1 point and the amount added, Figure 2 shows the relationship between the viscosity and the amount added, and Figure 3 shows the relationship between the viscosity and the N-1 point. showed the relationship. These results, especially the results shown in Figure 3, show that when typical known similar compounds are added, the viscosity of the resulting mixed liquid crystal increases significantly as the N-1 point increases; It will be understood that when the compound of formula () according to the present invention is added, the increase in viscosity accompanying the increase in the NI point of the resulting mixed liquid crystal is much smaller.

Next, the present invention will be specifically explained using examples.

Example 1 Anhydrous aluminum chloride 16.07 d in carbon disulfide 50 d
(0.120m01) and trans-4-n-propylcyclohexyl acetic acid chloride 2 while stirring at room temperature.
0.37 (0.100 m01) was added dropwise.

This was cooled to 0.degree. C., and a solution of biphenyl dissolved in 50 ml of carbon disulfide was added dropwise with stirring, and the mixture was allowed to react at 0.degree. C. for 5 hours, then returned to room temperature and allowed to react for 2 hours. After the reaction, carbon disulfide was distilled off, and then added to ice water and heated to 6'C.
The mixture was stirred for 1 hour. After cooling, it was extracted with ether, washed with water, dried, and after distilling off the ether, it was purified by recrystallization with ethanol to obtain the following compound 26,67 (0.0831 m01). To this compound were added 85 ml of triethylene glycol, 6.65 y (0.133 m01) of hydrazine hardate, and 13.87 y (0.246 m01) of potassium hydroxide, and the temperature was gradually raised while stirring, and the mixture was reacted at 180° C. for 3 hours. After cooling, 200'l of water was added and extracted with ether. After washing with water and drying over anhydrous sodium sulfate, the ether was distilled off, and recrystallization was performed using n-bexane-ethanol to obtain the following compound 23.1V (0.0755m01). Anhydrous aluminum chloride 12 in carbon disulfide 40a
．． 1y (0.907 m01) was added thereto, and 15.37 (0.0755 m01) of trans-4-n-propylcyclohexyl acetic acid chloride was added dropwise while stirring at room temperature.
This was cooled to 0°C, and while stirring, the above 1 compound 23 was added.
．． A solution of 17 (0.0755 m01) dissolved in 40 m1 of carbon disulfide was added dropwise to the mixture, and the mixture was reacted at 0°C for 5 hours, then returned to room temperature and reacted for 2 hours. After the reaction, carbon disulfide was distilled off, and the mixture was added to ice water and stirred at 60°C for 1 hour. After cooling, it was extracted with ether, washed with water, dried, and after distilling off the ether, it was purified by recrystallization with n-hexane-ethanol to obtain the following compound 28.87 (0.0610 m01). Triethylene glycol 50TLI1 hydrazine hardrate 3.79r (0.0756m01) and potassium hydroxide 7.87V (0.140m01) were added to this compound, and the temperature was gradually raised while stirring, and the reaction was carried out at 180°C for 3 hours. After cooling, 150 column d of water was added and extracted with ether. After washing with water and drying over anhydrous sodium sulfate, the ether was distilled off, and recrystallization was performed using n-hexane-ethanol to obtain the following compound 24.37 (0.0531 m01). Yield: 53.1% Transition temperature: 40°C (C-)S) 209
°C (S#N) 223 °C (N#I) Example 2 The following compound was obtained in the same manner as in Example 1.

Yield 49.6% Transition temperature 31°C (C→S) 202°C (S
=N) 207°C (N; I) Example 3 The following compound was obtained in the same manner as in Example 1.

Yield 50.8% Transition temperature 30°C (C→S) 206°C (S
#N) 215°C (N#I) Example 4 The following compound was obtained in the same manner as in Example 1.

Yield: 52.4% Transition temperature: 38°C (C-)S) 207°C (
Example 5 The following compound was obtained in the same manner as in Example 1.

Yield 53.1% Transition temperature 34℃ (C-)S) 211
5C (Sf2N) 220℃ (N=I)

[Brief explanation of the drawing]

The drawing shows one of the compounds according to the present invention/Compound F6.2 and a known compound having a similar chemical structure/
F6.6 compounds are used as base liquid crystals (
It shows changes in physical properties of mixed liquid crystals that occur when A is added in various proportions. Figure 1 shows the NI point and amount added, Figure 2 shows viscosity and amount added, and Figure 3 shows viscosity and N- It shows the relationship with one point.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R_1 and R_2 each represent a linear alkyl group having 1 to 7 carbon atoms. ] A compound represented by