JPS5921650A - Novel nematic liquid crystal compound - Google Patents

Abstract

NEW MATERIAL:A compound of formula I [R and R' are 1-7C straight chain alkyl; the cyclohexane ring is in the trans(equatorial-equatorial) configuration]. USE:An electrooptical display material, having a weakly positive dielectric anisotropy, and usable as a material for dynamic light scattering display cells in the state of a mixture with anther nematic liquid crystal compound having a negative or weakly positive dielectric anisotropy and as a material for electric field type display cells in the state of a mixture with another nematic liquid crsytal compound having a strongly positive dielectric anisotropy. PROCESS:A compound of formula II is reacted with a compound of formula IIIin an inert organic solvent, e.g. ether or benzene, in the presence of a basic compound, e.g. pyridine, as a catalyst according to the reaction formula to afford the aimed compound of formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel nematic liquid crystal compounds of benzoic acid derivatives useful as electro-optic display materials. The novel nematic liquid crystal compound provided by the present invention is a compound represented by the general formula. Typical liquid crystal display cells such as Niem Chadt (M-8chadt) (APPL
IED PHYSIC8LETTER81st 127~
128 (1971), ) or G.H. Hi/L/? Year (G-H Heilme)
ier) etc. (PROCEEDING OF THE
I, E, E, E.

1162-1171 (196B)] or the dynamic scattering mode cell proposed by G.H. Beilmeier (196B).
G-HHe i 1me is r) etc. [APPLI
ED PHYSIC8LETTER81391 (196
B)) Or D L White
White ) etc. [JOURNAL OF A
PPLIED PHYSIC845471B (1974)
), such as the guest-host cell proposed by

The liquid crystal materials used in these liquid crystal display cells are required to have various properties, but maintaining a nematic phase over a wide temperature range including room temperature is a common requirement for all types of display cells. This is an important characteristic. Most of the practical materials with such properties are usually made by mixing several or more components consisting of a compound that has a nematic phase near room temperature and a compound that has a nematic phase in the temperature range above room temperature. It is prepared by Many of the above-mentioned mixed liquid crystals currently in practical use are heated at temperatures of at least -30°C.
It is required to have a nematic phase over the entire temperature range from ~+65°C. In order to meet such requirements, 4,4'-substituted terphenyl is used as a compound that forms a nematic phase in a temperature range higher than room temperature.

4.4'-substituted biphenylcyclohexane, 4,4'
- crystalline phase at about 100°C, such as substituted penzoylogishibenzoic acid phenyl esters - amorphous phase transition temperature (C-
Compounds having a nematic phase-isotropic liquid phase transition temperature (N-I point) of about 200° C. are often used ().

In recent years, as liquid crystal display cells have been used for multiple purposes such as outdoors, there has been a need for liquid crystal display cells with a nematic temperature range higher than +65°C. For this purpose, a compound is required that has a nematic phase-isotropic liquid phase transition temperature (N-I point) higher than that of conventional compounds. The compound of formula (1) according to the present invention meets this requirement, and can significantly raise the nematic phase-isotropic liquid phase transition temperature (N-1 point) by mixing a small amount into a known liquid crystal mixture. I can do it. Furthermore, the compound of formula (1) is a 4,4'-substituted cyclohexylcarboxylic acid which the present applicant reported in JP-A-54-83694 as a nematic liquid crystal 4J material with excellent time division drive characteristics. Since it has extremely good compatibility with phenyl ester, even better mixed liquid crystals can be obtained by mixing it with these compounds.

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

The compound of formula (Il) is reacted with the compound of formula (III, ).

The transition temperatures of compounds of formula (I) prepared with lIf<t are shown in Table 1] I-5.

In the table, C represents a crystalline phase, S represents a smectic phase, N represents a nematic phase, and ■ represents an isotropic liquid phase.

The compounds of formula CI) according to the invention are scomatic liquid-crystalline compounds with weak positive dielectric anisotropy and therefore, for example:
It can be used as a material for dynamic light scattering display cells in a mixture with other nematic liquid crystal compounds that have negative or weak positive dielectric anisotropy, and also has strong positive dielectric anisotropy. It can be used as a material for field effect display cells in the form of a mixture with other nematic liquid crystal compounds.

Thus, preferred representative examples that can be used in combination with the compound of formula (IX) include, for example, 4,4'-substituted benzoic acid phenyl ester, 4,4'-substituted cyclohexanecarboxylic acid phenyl ester, 4, 4'-substituted cyclohexanecarboxylic acid biphenyl ester, 4(
4-Substituted cyclohexanecarbonyloxy)benzoic acid 4
'-substituted phenyl ester, 4(4-substituted cyclohegycyl)benzoic acid 4'-substituted phenyl ester, 4(4-
(substituted cyclohexyl) benzoic acid 4'-substituted cyclohexyl ester, 4,4'-biphenyl, 4,4'-phenylcyclohexane, 4,4'-ff, substituted terphenyl, 4,4'-biphenylcyclohexane, 2 (4'
-substituted phenyl) 5-substituted pyrimidine, and the like.

Table 2 shows 90% by weight of the base liquid crystal (A), which is currently widely used as a nematic liquid crystal material with excellent time-division driving characteristics, and the compound of formula (1) /161, 3.44, /%5. The N-I point measured for each mixed liquid crystal consisting of 10% by weight of each of Nochi Otsu is shown, and for comparison, the N-I point measured for the base liquid crystal (A) itself is shown. . In addition, the mother liquid crystal cell is 20% by weight, 16% by weight, 16% by weight, 8% by weight, 8% by weight, 8% by weight, 8JL amount%, 8Oki, 1% and 8M amount% in Table 2. N-I point (''C) (A) 54.0 (A)-1-(A61) 74.4(A) 10(A
2) 74.5(A) +(/163)
74.7 (A) + (A4) 7.
3.9(A) +(/165) 74.7(
A) + (/l66) 74.3(A) +(/I
67) 74.5 From the data listed in Table 2, it can be seen that addition of 10% by weight of the compound of formula (1) raises the N-I point of the mixed liquid crystal mixture by about 20°C. The practical value of the compound of formula (Il) is that the upper limit of the operating temperature range can be raised by adding a small amount.The effects of the present invention are also clarified by the following comparative experiments. The structure is similar to the compound of formula (I) according to the present invention, and the N-
Point I'fr: For the purpose of browning, the Yachi compound of the formula used in the formula was mixed in various proportions with the above-mentioned parent liquid crystal mass.

Similarly, one of the compounds according to the invention, ie, a compound of the formula, was mixed in various proportions into the parent liquid crystal matrix. Thus obtained 2
For the mixed liquid crystals of class S, each N7I point was measured. Based on these measurement results, N,
, showed the relationship between -1 points and added rats. From these facts,
It will be understood that the compound of formula (1) according to the present invention has a much greater increase in the N-I point when compared to typical known similar compounds.

Example 1 To the formula Ho ()4c, r+, no compound 20.4 y <
o, 1o.

mol) and the formula n, -C,4COO→C)←COCl
30.6g (0,100mol) of the compound iv
F 2 Q Oml dibath vulgarization while stirring at room temperature: / 15.8,! 9 (0,200 mol) was added dropwise. After the dropwise addition was completed, the mixture was refluxed for 2 hours. After the reaction was completed, the reaction product was extracted with toluene. After washing the extract with water and drying, toluene was distilled off from this liquid, and the obtained reaction product was recrystallized from acetone to obtain the following compound 53.71 (0
,0717rnol) was obtained.

n-c, H2/Q)-c, ao (anti-coo%ctH.

Yield rate: 71.7% Transition temperature 169℃ (C-+5) 141℃ (sgN) 289℃ (NgI) Example 2 The following compound was obtained in the same manner as in Example 1.

Yield rate 73.7% Transition temperature 156℃ (C-+S) 1.36℃ (sgN) 291°C (NgI) Example 3 The following compound was obtained in the same manner as in Example 1.

Yield rate 74.1% Transition temperature 1389C (C4S) 146℃ (sgN) 293℃ (Ngx) Example 4 The following compound was obtained in the same manner as in Example 1.

Yield rate 70.9% Transition temperature 127℃ ((-+5) 1130℃ (sgN) 2'80℃ (Nod I) Example 5 The following compound was obtained in the same manner as in Example 1.

Revenue rate 72.4% Transition temperature 132℃ (C→S) 135°C (5-N) 292℃ (N-1) Example 6 The following compound was obtained in the same manner as in Example 1.

n-C,H,-Q-Coo-G'C00kn-bleaching
Rate 712% Transition temperature 133°C (C=S) 140°C (S=N) 287°C (N#I) Example 7 The following compound was obtained in the same manner as in Example 1.

Yield rate 70.5% Transition temperature 152℃ (C→5) 167℃ (siN) 290℃ (N:!I)

[Brief explanation of drawings]

Figure 1 shows the N of a mixed liquid crystal obtained by adding compound /166, which is one of the compounds according to the present invention, and a known compound a) having a structure similar to this to a currently widely used base liquid crystal. It is a chart showing the relationship between -1 point and addition site.

Claims (1)

[Claims] general formula A compound represented by