JPS6130558A - Chlorine-containing chiral liquid crystal compound - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (R is 1-12C straight-chain alkyl; the group of formula II is optically active 2-methylbutyl). EXAMPLE:(+)-4-n-Butyloxy-3-chlorophenyl-4-(2''-methylbutyl)biphenyl-4' -carboxylate. USE:A component of smectic liquid crystal composition exhibiting ferroelectric property. It may be used singly in a ferroelectric smectic liquid crystal display element or electro-optical element. PREPARATION:The compound of formula I can be prepared by hydrolyzing 4- (+)- (2''-methylbutyl)-4'-cyanobiphenyl of formula III, reacting the resultant compound of formula IV with excess thionyl chloride to obtain the compound of formula V, and reacting the product with the compound of formula VI.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a chlorine-containing chiral liquid crystal compound used in display elements or electro-optical elements.

[Conventional technology]

Conventionally, liquid crystal display elements using nematic liquid crystal, which are used in the display parts of clock calculators, etc., have a response speed that is much slower than other display elements such as light emitting diodes, so high-speed response is required. fields, for example, optical communications;
Application to liquid crystal display elements in printer heads has been limited.

Recently, liquid crystal display elements using smectic liquid crystals exhibiting ferroelectricity have been reported as liquid crystal display elements exhibiting high-speed response (for example, N, M, etc.).

Quark, S., T., Lagerwa)
, Appl, Phys, Lett.

36, 899 (1980)) is attracting attention.

Smectic liquid crystals exhibiting ferroelectricity include chiral smectic C phase, chiral smectic H phase,
These exhibit a layered structure, with liquid crystal molecules tilted rather than perpendicular to the stacking direction of the layers. This direction of inclination is
Spiral in the stacking direction of the layers? The liquid crystal molecules are arranged in a coiled manner, and spontaneous polarization occurs in a direction parallel to this layer and perpendicular to the liquid crystal molecules, exhibiting ferroelectricity. This helical structure is thought to be the reason for the ferroelectricity. A material exhibiting ferroelectricity exhibits responsiveness to an electric field as a ferroelectric substance, and reverses the direction of spontaneous polarization and rearranges itself according to the direction of the electric field.

[Problem to be solved by the invention]

Conventionally, many Shipp base-type compounds as shown below have been studied as ferroelectric liquid crystals.

p-Decyloxybenzylidene-P'-amino-2-methylbutyl-cinnamic acid ester (DOBAMBO) However, such a thick base type compound is easily hydrolyzed, so there is a problem that it is easily decomposed by moisture.

Further, as an ester compound exhibiting a chiral smectic C phase, a compound represented by the general formula (11) below was also known.

(G, W, Gray et al. Mol Cryst, Li
q, Cryst, 1976.

(R is a linear alkyl group having 5 to 10 carbon atoms) Although this ester compound is resistant to moisture, its response is slow;
In addition, the temperature at which the chiral smectic phase is exhibited is considerably higher than room temperature, and if the compound actually acts on the entire display element, the display element must be heated completely before use.

[Means to solve the problem]

The object of the present invention is to solve the above-mentioned problems and to develop a chlorine-containing chiral liquid crystal compound that is used to construct a smectic liquid crystal composition that exhibits ferroelectricity that exhibits high-speed response and can operate even near room temperature. It is about providing.

The chlorine-containing chiral liquid crystal compound of the present invention has the general formula (1)
It is a compound represented by, and its general name is (t)-4-
It is n-flufoxy 3-chlorophenyl-4-(2'-methylbutyl)biphenyl-41-carboxylic acid ester.

(Here, RFi indicates a straight chain alkyl group having 1 to 12 carbon atoms. 11.E, .28.-Tenichi. H8-1 optically active □ Old H3 2-methylbutyl group is shown.) Detailed explanation in Examples However, the compound of general formula (D) is compared with the compound of general formula (...) that does not contain chlorine,
It tends to exhibit chiral smectic C phase.

The optically active group of the compound (1) of the present invention is #'i (t)2-methylbutyl group or (-) as 2-methylbutyl group.
Although either 2-methylbutyl group may be used, (t)2-methylbutyl group, which is synthetically simple, is more preferable.

The number of carbon atoms in the linear alkyl group R is preferably from 1 to 12, more preferably from 2 to 8, since the melting point will be high if it is too small, and the viscosity will be high if it is too large.

The compound represented by general formula (1) may be used alone in ferroelectric smectic liquid crystal display elements or electro-optical elements, but the temperature at which it exhibits chiral smectic C phase and the helical pitch may be adjusted. In order to perform color display, it is mixed with other ferroelectric smectic liquid crystals, smectic liquid crystals, nematic liquid crystals, or non-liquid crystals, or even with dichroic dyes to form a smectic liquid crystal composition exhibiting ferroelectric properties. The content of the compound represented by general formula (1) in the smectic liquid crystal composition exhibiting ferroelectricity of the present invention is preferably 1% by weight or more, more preferably 5% by weight or more.

Compounds that can be mixed with the compound of general formula (1) of the present invention and used as a ferroelectric liquid crystal include, for example, the following compounds.

R' -0(Xcoo Examples of the color dye include dyes used in so-called guest-host type liquid crystal display devices, such as trisazo and anthraquinone dyes.

A ferroelectric liquid crystal display element or an electro-optical element comprises a plurality of substrates, at least one of which is transparent, and which has electrodes on all or part of the substrate, which are arranged so as to sandwich the entire liquid crystal layer, and which surround the liquid crystal layer. In the liquid crystal display element, the thickness between the substrates is α
5μ to 20p is preferable. Further, each of the substrates may be subjected to alignment control processing in a parallel direction. As a means for controlling this alignment, an alignment control film may be applied to a part or the entire surface of the electrode substrate.

As the alignment control film, a polymer material such as polyimide having a refractive index of 1.5 or more is preferable. Furthermore, it is preferable that at least one polarizer is attached to the liquid crystal element. At least two electrode substrates are required, but more electrode substrates may be stacked and used.

The compound of general formula (1) of the present invention can be synthesized, for example, through the following three steps.

4-(t)-(2'-methylbutyl)-4'-cyanobiphenyl@) f The method of Gray et al. (Mo1.0
r7st.

Liq, 0ryst, 1976, 57, 18
9-211') to form the compound (conversion), which was reacted with excess thionyl chloride to form compound (7), and then reacted with compound (6) to form the desired compound (
1)? Can be synthesized.

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

〔Example〕

Example-1 4-(t)-(2'-methylbutyl)-4'-cyanbiphenyl (!It) (Merck M') 'k Gr
(g)-4-( obtained by hydrolysis by the method of ay et al.
2'-Methylbutyl)-biphenyl-4'-carboxylic acid (transformed) 2,689 (0,010 mol), thionyl chloride 005 mol, and carbon tetrachloride 50. Add mixture K of
I got ft. fft of acid chloride CVy dissolved in toluene
After adding and stirring for 6 hours, the precipitated pyridine hydrochloride t
The filtrate is washed with dilute hydrochloric acid and water in this order. After drying the organic layer with 9 um of anhydrous sulfuric acid, the solvent was distilled off to obtain a solid. This was recrystallized from ethanol, further subjected to toluene-activated alumina chromatography, and further recrystallized from ethanol to obtain the desired (t)-4-n.
-fluoroxy-3-chlorobuenyl-4-(2'-methylbutyl)biphenyl-4'-carboxylic acid ester (
A general formula (1) in which R is an n-butyl group was obtained.

Yield: 2.4f Yield: 553 According to observations using a polarizing microscope equipped with a chip-hot stage, this compound transitions from a crystalline phase to a cholesteric phase at 6 to 7 degrees Celsius during heating, and then changes to an isotropic liquid phase with an odor of 128.0 degrees Celsius. metastasized,
Further, when the temperature was lowered, the isotropic liquid phase transitioned to a cholesteric phase at 12aO°C, and further transitioned to a chiral smectic C phase at 6aO°C. Another 2c/w
The chiral smectic C phase remained even when the temperature was lowered to 40°C. This is shown in Table-1.'5 K Gr&7
When compared with a compound of the general formula (II) in which the alkyl group R is n-butyl, in the compound of the present invention in which C1 is introduced, a chiral smectic C phase is induced, although it is simonotropic due to the introduction of C1. I understand.

The R spectrum of this compound is shown in FIG.

The HNMR spectrum of this compound was as follows.

δα8~2. Ocomplex m 16112.
60 ABX pattern JAB=14H
g, JAX-JBX 6Hm 2H 4,05 triplet J-6Htrr 2
169 to 43 complex m 111
1 Example-2 3-chloro-a-n-butyloxyphenol in Example-1 [in the same way, 3-chloro-4-n-hexyloxyphenol was used, and in the same way, (t) -4-n
-hexyloxy-3-chlorophenyl-4-(2'-
Methylbutyl)biphenyl-4'-carboxylic acid ester (in general formula (1), R is n-hexyl group) was obtained. Yield 2.60 f, yield 54.3-.

Observation under a polarizing microscope with a hot stage shows that when the temperature of this compound wire is increased to 5.7.8°C, the crystal changes to a chiral smectic C phase.

At 659℃, it changes to cholesteric phase and 12α0
It was found that at ℃ it turns into an isotropic liquid.

Further, when the temperature was lowered, no chiral smectic phase was observed even when the temperature was lowered to 33°C at a rate of 2°C/lll1n.

As shown in t-1 Table-1, the general formula (
1) Compared to the compound in which the alkyl group is n-hexyl, the compound of the present invention into which Cl is introduced has a temperature range of the chiral smectic C phase that is much closer to room temperature due to the introduction of OX. I know that there is.

The R spectrum of this compound is shown in FIG.

The IIINMIt spectrum of this compound was as follows.

δ0.8~2. Oaoplex m 20H2,
60ABM pattern JAB-14Hz,
JAz = JBz drama 6Htx 2H 405 triplet J-6Hz 2H6,9
A43 aoplex m 11H Example-3
~7 Using the following 7 enol in place of 5-chloro-4-n-butyloxyphenol in Example-1, the second
The ester compounds shown in the table were obtained.

〔Effect of the invention〕

The compound of the present invention is stable, and the ferroelectric chiral smectic liquid crystal display element using the compound of the present invention is
As can be seen from the table, since the chiral smectic 0 phase is close to room temperature, it can be used without heating the display element.

[Brief explanation of drawings]

FIGS. 1 and 2 are R spectra of the compounds of Example 1 and Example 2 of the present invention. Figure 1 Procedural amendment (method) % formula % 1. Indication of the case Patent Application No. 152130 of 1982 2. Name of the invention Chlorine-containing chiral liquid crystal compound 3. Person making the amendment Relationship to the case Patent applicant residence Location 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Name
(004) Asahi Glass Co., Ltd. 8, Number of inventions increased by amendment None 7, Target of amendment Drawing 8, Contents of amendment

Claims (1)

[Claims] (1) Chlorine-containing chiral liquid crystal compound represented by the general formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (I) (Here, R represents a linear alkyl group having 1 to 12 carbon atoms, and ▲There are mathematical formulas, chemical formulas, tables, etc. ▼ indicates the optically active 2-methylbutyl group.)