JPS60226845A - Novel nematic liquid crystal compound - Google Patents

Abstract

NEW MATERIAL:A compound of formula I [R and R' are 1-9C straight chain alkyl; 3 cyclohexane rings are respectively trans (equatorial-equatorial) configurations]. USE:An electrooptical display material capable of exhibiting weakly negative dielectric anisotropy and increasing the nematic phase-isotropic liquid phase transition temperature. PREPARATION:A compound of formula II is reacted with a compound of formula III in an inert organic solvent, e.g. ether, benzene or toluene, in the presence of a base, e.g. pyridine, to give the aimed compound of formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel nematic liquid crystal compounds of cyclohexylcyclohexanecarboxylic 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.

M-Shut (M Medium 5) is a typical liquid crystal display cell.
chadt) etc. [APPLIED PHYSIC8LE
Field effect cell (field fist effect) proposed by TTER818127-128 (1971))
Mode Sell) or G.H. Beilmeyer (G.
*HH Heilmeier) etc. (PROCEEDING
OF THE 1. E, E, E, 561162-11
71 (1968)) or the dynamic scattering mode cell proposed by G.H.
ier ) etc. (APPLIED PHYSIC8LET
TER813, 91 (1968)) or DL White etc. [JOURNAL
OF APPLIED PHYSIC845,471B
(1974):), etc.

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 produced 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 at a temperature above room temperature. Prepared by. Most of the above-mentioned mixed liquid crystals currently in practical use are at least -30°C to +6°C.
It is required to have a nematic phase over the entire temperature range of 5°C. In order to meet such requirements, 4. compounds have a nematic phase in a temperature range higher than room temperature.
4'-substituted terphenyl, 4.4'-tm biphenylcyclohexane, 4.4'-substituted benzoyloxybenzoic acid phenyl ester, etc., which have a crystal phase-nematic phase transition temperature (C-N point) of about 100°C. Approximately 200
Nematic phase-isotropic liquid phase transition temperature in °C (N-I point)
Compounds having the following are often used.

In recent years, as liquid crystal display cells have been used for multiple purposes both indoors and outdoors, there has been a need for cells with a nematic temperature range higher than +65°C. For this purpose, a compound is required which has a higher nematic phase-isotropic liquid phase transition temperature (N-I point) than conventional compounds.

The compound of formula (I) according to the present invention meets this requirement, and can significantly raise the nematic phase-isotropic liquid phase transition temperature (N-I point) by mixing a small amount into a known liquid crystal mixture. Can be done. Furthermore, the compound of formula (I) is a 4,4'-M chlorohexyl compound which the present applicant reported in JP-A-54-83694 as a nematic liquid crystal material with excellent time-division driving characteristics. Since it has extremely good compatibility with carboxylic acid phenyl ester, even better mixed liquid crystals can be obtained by mixing it with these compounds.

The compound of formula (I) according to the present invention can be produced according to the following production method. A basic compound such as pyridine is added to the compound of formula (■) in an organic solvent such as ether, benzene, or toluene. The compound of formula (I) according to the present invention is produced by reacting the compound of formula (uI) as a catalyst.

The transition temperature of the compound of formula (I) thus prepared is
Listed in the table.

In Table 1, C represents a crystalline phase, S represents a smectic phase, N represents a nematic phase, and ■ represents an isotropic liquid phase.

The compound of formula (I) according to the invention is a nematic liquid crystal compound with weak negative 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 it can also be used as a material for dynamic light scattering display cells. It can be used as a material for field effect display cells in the form of a mixture with other nematic liquid crystal compounds.

Preferred representative examples of K, which can be used in combination with the compound of formula (I), include, for example, 4+4' t
! Substituted benzoic acid phenyl ester, 4.4'-f% cyclohexanecarboxylic acid phenyl ester, 4.4'-substituted cyclohexanecarboxylic acid biphenyl ester, 4(4
-Substituted cyclohexanecarbonyloxy)benzoic acid 4'
-Substituted phenyl ester 4 (4-substituted cyclohexyl)
Benzoic acid 4'-substituted phenyl ester, 4(4-!substituted cyclohexyl)benzoic acid 8% 4'-substituted cyclohexyl ester, 4. C-717m biphenyl, 4.4'-substituted phenylcyclohexane, 4.4'-substituted terphenyl,
Examples include 4.4'-biphenylcyclohexane, 2(4'-substituted phenyl)5-substituted pyrimidine, and the like.

Table 2 shows nematic liquid crystal materials with excellent time-division drive characteristics and 1 to 90% of the currently widely used base liquid crystal (A).
and the compound of formula (I) shown in Table 1, /162
The N-I point measured for each mixed liquid crystal consisting of 10% by weight of each of A5 and Fu4 is displayed, and for comparison, the N-I point measured for the base liquid crystal (A) itself is displayed. It is something. The base liquid crystal (A) consists of 8% by weight, 8% by weight, 8% by weight, 8% by weight, and 8% by weight.

Table 2 Point N-I (A) 54.0 (A) + (/161 '> 76.4 (A) + (/l62) 78.2 (A) + (Junior 5) 78.0 (A) +(A4) 78.0 From the data posted in Table 2, the compound of formula (I) has 1
By adding 0% by weight, the N-I point of the mixed liquid crystal (A) is increased to 2.
It can be understood that the temperature can be increased by 0°C or more. The high practical value of the compound of formula (I) is that the upper limit of the operating temperature range can be raised by addition of such a small amount.

The effects of the present invention are also clarified by the following comparative experiments. Known compounds of formulas used for the purpose of increasing the N-I point of mixed liquid crystals were mixed in various proportions with the above-mentioned base liquid crystal (A).

Similarly one of the compounds according to the invention, i.e. formula %) The compounds were mixed in various proportions into the parent liquid crystal (At).

Regarding the two types of mixed liquid crystals obtained in this way, each N
- Point I was measured. Based on these measurement results, the relationship between the NI point and the amount added is shown in FIG. 1 of the attached drawings.

From these facts, it can be understood that the compound of formula (I) according to the present invention has a much larger increase in Ni point with respect to the amount added than typical known sapphire-like compounds.

Example 1 Formula Ho-()xca, CH2(pΣ"-03H?)
Compound 24.69 (0,100 mol), formula n C5
H7+ COCl compound 27, 11 (0,100
Dissolve 200 mKg of A) mol) and add 15.8F pyridine (0,200
mol) was added dropwise. After the 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 a mixed solvent of ethanol and hexane to obtain 2 g (0,796 mol) of the following compound 6B.

Yield 796% Transition temperature 144°C (CH2) 191
°C (SIN) 600 °C or higher (Nze■) Example 2 The following compound was obtained in the same manner as in Example 1, yield: 77
．． 4% Transition temperature 156℃ (c->s) 172℃
(S-N) 600°C or higher (NzI) Example 6 The following compound was obtained in the same manner as in Example 1.

Yield 78.5% Transition temperature 138℃ (c->3
) 204°C (S port N) 600°C or higher (N-I) Example 4 The following compound was obtained in the same manner as in Example 1.

Yield 80.1% Transition temperature 162°C (C-+S
)209℃ (SzN) 600℃ or more (L=I)

[Brief explanation of the drawing]

Figure 1 shows one of the compounds according to the invention (,%2)
Compounds and known compounds with similar chemical structures'
The frame a) is a mother liquid crystal, which is currently widely used, (Al
It is a chart showing the relationship between the N-I point and the amount of each mixed liquid crystal obtained by adding the liquid crystal to the liquid crystal. Agent Patent Attorney Katsutoshi Takahashi

Claims (1)

[Claims] general formula A compound represented by