JPH072687B2 - Tolan compound and liquid crystal composition - Google Patents

Description

The present invention relates to a liquid crystal compound and a liquid crystal composition containing the compound.

[Prior Art] Conventionally, as a tolan compound showing ferroelectricity, for example, 4'-decyloxy-4- (2-methylbutyloxycarbonyl) tran (for example, JP-A-62-228043).
It has been known.

[Object of the Invention] The inventors of the present invention have proposed a tolan compound having a wider temperature range showing ferroelectricity than the conventional compounds, or a tolan compound useful as a constituent component of a liquid crystal composition, and a liquid crystal containing the tolan compound. As a result of intensive studies on the composition, the present invention has been achieved.

[Means for Achieving the Object of the Invention] That is, [In the formula, R is an alkyl group having 3 to 18 carbon atoms. X is-
It is 0- or a single bond (direct bond). A ₁ and A ₂ are F and C
l, -CN, an -NO ₂ and chosen from the group consisting of -CF ₃ optionally substituted with a substituent phenylene group or biphenylene group, A ₁ and A ₂ do not become a phenylene group at the same time. n is an integer of 2 to 7. R'is 2 to 2 carbon atoms
10 straight chain alkyl groups. In addition, ^* indicates that it is optically active. ] A liquid crystal composition exhibiting a chiral smectic phase, comprising at least one of the tolan compound represented by the formula [1] and the tolan compound represented by the general formula (1) as a compounding component.

The tolan compound of the present invention includes one that can observe the liquid crystal state alone and a substance that is useful as a constituent component of the liquid crystal composition even if the liquid crystal state cannot be observed alone.

In the general formula (1), the alkyl group having 3 to 18 carbon atoms for R is a linear alkyl group (propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group). , Dodecyl group, tetradecyl group, octadecyl group, etc.), branched alkyl group (1-methylpropyl group, 1-methylbutyl group, 1-methylheptyl group, 2-methylbutyl group, 2-methylpentyl group,
2-methylhexyl group, 2-methylheptyl group, 2-methyloctyl group, 3-methylpentyl group, 4-methylpentyl group, 4-methylhexyl group, 5-methylheptyl group, 6-methyloctyl group, 7- Methylnonyl group, 8-
Methyldecyl group, 9-methyldecyl group, etc.), alkyl group having a substituent [for example, alkyl group substituted with Cl (2-chloropropyl group, 2-chlorobutyl group, 2-chloropentyl group, 2-chlorohexyl group, 2 -Chloroheptyl group, 2-chlorooctyl group, 1-chloro-2-methylpropyl group, 1-chloro-2-methylbutyl group, 1
-Chloro-3-methylbutyl group etc.), an alkyl group substituted with F (2-fluoropropyl group, 2-fluorobutyl group, 2-fluoropentyl group, 2-fluorohexyl group, 2-fluoroheptyl group, 2- Fluorooctyl group, 1-fluoro-2-methylpropyl group, etc., alkyl group substituted with alkyloxy group (2-methoxypropyl group, 2-ethoxypropyl group, 2-propyloxypropyl group, 3-methoxybutyl group) , 3-ethoxybutyl group, 3-propyloxybutyl group, 4-methoxypentyl group, 4-ethoxypentyl group, 4-propyloxypentyl group, etc.). These alkyl groups (branched or substituted alkyl groups) may be optically active groups or non-optically active groups. Of these, a linear alkyl group having 6 to 18 carbon atoms is preferable.

X is preferably -0-.

A ₁ and A ₂ may be substituted with 1 to 4 F, or 1 or 2 substituents selected from the group consisting of Cl, —CN, —NO ₂ and —CF _3. Examples thereof include an optionally substituted phenylene group or biphenylene group. However, when no A _1, A ₂ are both substituents, A _1, A ₂ does not become a phenylene group at the same time.

Preferred among A ₁ and A ₂ is a phenylene group or a biphenylene group substituted with 1 to 4 F, and considering that the temperature range showing ferroelectricity is around room temperature, Preferred are phenylene groups substituted by 1 to 4 F.

n is preferably an integer of 2-5. When n is less than 2, the temperature range of the chiral smectic C phase (hereinafter abbreviated as Sc ^* phase) is narrow, and when it exceeds 5, it is difficult to obtain the optically active alcohol as a raw material, and another smectic phase is present at a temperature lower than the Sc ^* phase. Is likely to appear, which is not preferable.

Examples of the linear alkyl group having 2 to 10 carbon atoms of R'include an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group,
Examples thereof include a heptyl group, an octyl group, a nonyl group and a decyl group. Of these, an ethyl group is preferable in view of easy availability of the optically active alcohol.

Specific examples of the compound represented by the general formula (1) are shown in Table-
Examples thereof include compounds having a group as shown in 1.

The compound represented by the general formula (1) may be used alone, but is preferably used as a mixture of two or more kinds.

The compound of the general formula (1) can be synthesized, for example, through the following steps (see Japanese Patent Application No. 62-210719). In the formula below,
R, X, n and R'are the same as in the general formula (1). k and l are 1 or 2, p and q are integers of 0 to 4, provided that p + q ≦ 4.

The liquid crystal composition of the present invention contains at least one compound represented by the general formula (1) as a compounding component. As the liquid crystal compound, a chiral smectic liquid crystal other than the compound of the general formula (1) of the present invention, for example, the compound of the general formula (1) described in JP-A-62-135449, and the compound described in JP-A-62-228043. Compounds of general formula (1), 4-n-alkyloxy-
4'-biphenylcarboxylic acid-p '-(2-methylbutoxycarbonyl) phenyl ester, 4-n-alkyloxy-4'-biphenylcarboxylic acid-2-methylbutyl ester, p-alkyloxybenzylidene-p'-
Ferroelectric liquid crystals such as amino-2-chloro-propylcinnamate, p-alkyloxybenzylidene-p'-amino-2-methylbutylcinnamate, and / or 4- (p-alkyloxybiphenyl-p'-oxy Carbonyl) -4 '-(2-methylbutyloxycarbonyl) -cyclohexane, pn-alkyloxybenzylidene-p'-(2-methylbutyloxycarbonyl)
Ordinary chiral smectic liquid crystals such as aniline, and / or 4-n-alkyloxy-4'-biphenylcarboxylic acid-p '-(n-alkyloxycarbonyl)
Smectic liquid crystals such as phenyl ester and 4-n-alkyloxy-4′-biphenylcarboxylic acid-n-alkyl ester may be contained. Also a dichroic dye,
For example, it may contain an anthraquinone dye, an azo dye, or the like.

The formulation examples of the liquid crystal composition are as follows.

(I) Compound of general formula (1): 30 to 100% by weight (preferably 40 to 80% by weight) (II) Other chiral smectic liquid crystal: 0 to 70% by weight (preferably 30 to 60% by weight) (III ) Other smectic liquid crystals: 0 to 60% by weight (preferably 30 to 50% by weight) (IV) Dichroic dye: 0 to 5% by weight The liquid crystal composition of the present invention comprises a chiral smectic phase, for example, a chiral smectic C phase. The upper limit of the temperature range showing (Sc ^* phase) (that is, the temperature at which the Sc ^* phase changes to a smectic A phase, a chiral nematic phase or an isotropic liquid phase) is usually 60 to 70 ° C, and its lower limit (that is, from solid to Sc ^* Temperature at which the phase changes) is usually -10 to 0 ° C and shows ferroelectricity in this range. Liquid crystals exhibiting ferroelectricity are
By applying a voltage, an optical switching phenomenon is caused, and a display element having a fast response can be manufactured by utilizing the phenomenon (for example, JP-A-56-107216, JP-A-59-118744, NAClark, ST). STLagerwall; Applied Physics
Letter (Applied Physics Letter) 36, 899 (1980) , etc.].

The liquid crystal composition of the present invention is sealed in a liquid crystal cell having a cell interval of 0.5 to 10 μm, preferably 0.5 to 3 μm in vacuum, and an optical switching element (display element) is provided by installing polarizers on both sides.
Can be used as

The above liquid crystal cell was provided with a transparent electrode, and the surface was subjected to orientation treatment.
It can be manufactured by laminating two glass substrates with a spacer interposed therebetween. Examples of the spacer include alumina beads, glass fiber, and polyimide film. As the alignment treatment method, a normal alignment treatment, for example, a polyimide film, a rubbing treatment, or a Si
O Diagonal vapor deposition can be applied.

[Examples] Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto. In the following examples,% indicates% by weight.

In the following description, the values of phase transition temperature and Ps are slightly changed depending on the measuring method and the purity.

Example 1 (1) Synthesis of p-decyloxyphenylacetylene (i) To 60 ml of dimethyl sulfoxide were added 8.8 g of p-iodophenol, 9 g of n-decyl bromide and 2.7 g of potassium hydroxide, and the mixture was stirred overnight at room temperature. It was poured into water and extracted with 100 ml of toluene. After washing with water and drying, hexane was distilled off by passing through a short column filled with silica gel to obtain 13 g of the following liquid compound.

(Ii) 10.8 g of this compound was dissolved in 30 ml of triethylamine together with 1.7 g of propargyl alcohol to give 114 m of copper iodide.
g and 210 mg of dichlorobis (triphenylphosphine) palladium (II) were added, and the mixture was stirred for two days and nights, then poured into water and extracted with 120 ml of ether. The extract was washed with diluted hydrochloric acid, water and an aqueous solution of sodium hydrogen carbonate, dried and then the ether was distilled off. It was dissolved in hexane, passed through a short column of activated alumina, hexane was distilled off, and then recrystallized from hexane to obtain 4.2 g of the following compound.

(Iii) 4.0 g of this compound was dissolved in 30 ml of benzene, 2.4 g of manganese dioxide and 1.0 g of potassium hydroxide were added, and the mixture was stirred for 1 hour. After separating the solid matter and distilling off benzene, it was dissolved in hexane and passed through a short column of activated alumina to distill off the hexane to obtain 2.6 g of liquid p-decyloxyphenylacetylene.

(2) Synthesis of optically active p-iodo-o-fluoro-benzoic acid 4-methylhexyl ester (i) Commercially available p- in 400 g of a mixed solution of concentrated hydrochloric acid, water and ice (1: 1: 2) To a heterogeneous solution obtained by adding 25 g of amino-o-fluorotoluene and cooling with ice, 100 ml of an aqueous solution containing 15 g of sodium nitrite was added dropwise. One hour after the completion of the dropwise addition, an aqueous solution prepared by dissolving 35 g of potassium iodide in 50 ml of water was added and the temperature was returned to room temperature. After stirring at room temperature for 2 hours, the organic layer was extracted with ether. The ether layer was washed with an aqueous sodium hydrogen sulfite solution, an aqueous sodium hydrogen carbonate solution and water, dried, and then the ether was removed under reduced pressure. The target substance p-iodo-o-fluorotoluene (boiling point: 99-102 ° C / 40mmH
g) 27 g were obtained.

(Ii) To a mixed solution of 200 ml of water and 150 ml of pyridine was added 25 g of p-iodo-o-fluorotoluene synthesized in (i), and the mixture was heated under reflux. To this, 45 g of potassium permanganate was added in several times, and after the addition was completed, the reflux was continued for another hour. Unreacted p-iodo-o-fluorotoluene was removed by distillation and then cooled. After cooling, manganese dioxide was removed by filtration, and concentrated hydrochloric acid was added to the resulting colorless and transparent aqueous solution to acidify it to obtain a white precipitate. The precipitate was filtered, dried, and recrystallized from toluene to obtain 10.3 g of the desired product, p-iodo-o-fluorobenzoic acid.

(Iii) 3.0 g of p-iodo-o-fluorobenzoic acid and 5 ml of thionyl chloride were heated under reflux for 6 hours, and excess thionyl chloride was distilled off to obtain p-iodo-o-fluorobenzoic acid chloride. It was This product was not particularly purified and used as a toluene solution in the next step. On the other hand, 1.3 g of optically active 4-methylhexanol and 1.0 g of pyridine dissolved in 20 ml of toluene were kept on ice, and the toluene solution of the above acid chloride was added dropwise thereto under stirring for about 30 minutes. The mixture was stirred on a 90 ° C water bath for 5 hours. After cooling, add 6N hydrochloric acid and water to acidify the mixture, separate the organic layer, wash with water, wash with saturated aqueous sodium hydrogen carbonate, wash with water, and then remove the toluene under reduced pressure. Purification by a column gave 3.7 g of optically active p-iodo-o-fluorobenzoic acid 4-methylhexyl ester.

(3) Synthesis of compound No. 1 in Table 1 1.3 g of p-decyloxyphenylacetylene was used as an optically active compound.
-Iodo-o-fluorobenzoic acid-4-methylhexyl ester was dissolved in 20 ml of triethylamine together with 2.0 g, and after nitrogen substitution, 19 mg of copper (I) iodide and 35 mg of dichlorobis (triphenylphosphine) palladium (II) were added, After stirring overnight, the mixture was poured into water and extracted with 100 ml of ether. The extract was washed with diluted hydrochloric acid and water, dried and then the ether was distilled off. Dissolve in hexane, pass through a short column of activated alumina, distill off hexane, and recrystallize with ethanol. 1.6 g of No. 1 compound in Table-1 (yield 65%, p-decyloxyphenylacetylene standard) ) Got.

IR-spectrum, H-NMR spectrum and F of the above compound
-NMR spectra are shown in Fig. 1, Fig. 2 and Fig. 3, respectively.

Example 2 (1) Synthesis of pn-decyloxy-m-fluorophenylacetylene (i) To 350 ml of water, 24.5 g of o-fluorophenol and 14.4 g of potassium hydroxide were added, and after cooling to 10 ° C or lower,
Iodine (55.6 g) was added, and the mixture was stirred overnight. The produced oil was extracted with ether and washed with an aqueous solution of sodium thiosulfate and water, then the ether was distilled off and then distilled under reduced pressure to obtain liquid p-iodo-o-fluorophenol (boiling point: 155 to 157 ° C / 5 mmHg ) 16g was obtained.

(Ii) 3.0 g of this compound was dissolved in 30 ml of dimethyl sulfoxide, 0.83 g of potassium hydroxide and 2.7 g of n-decyl bromide
After adding g and stirring the mixture at room temperature for 24 hours, it was poured into water and extracted with 100 ml of hexane. After washing with water and drying, it was passed through a short column packed with a silica gel column and hexane was distilled off to obtain 3.9 g of liquid pn-decyloxy-m-fluoroiodobenzene.

This compound (3.9 g) was dissolved in triethylamine (10 ml) with propargyl alcohol (0.7 g), copper iodide (40.0 mg) and dichlorobis (triphenylphosphine) palladium (I
I) 85.0 mg was added, and the mixture was stirred for 24 hours, then poured into water and extracted with 50 ml of ether. After washing with dilute hydrochloric acid, water, an aqueous solution of sodium hydrogen carbonate and water, and drying, the ether was distilled off, the residue was dissolved in hexane, passed through a short column of activated alumina, and hexane was distilled off to obtain 2.4 g of the following compound. .

(Iii) 2.4 g of this compound was dissolved in 30 ml of benzene, 2.4 g of manganese dioxide and 1.0 g of potassium hydroxide were added, and the mixture was stirred for 1 hour. After separating the solid matter and distilling off benzene, it was dissolved in hexane and passed through a short column of activated alumina to distill off the hexane to obtain liquid pn-decyloxy-m-.
2.0 g of fluorophenyl-acetylene was obtained.

(2) Synthesis of optically active p-iodobenzoic acid 4-methylhexyl ester (i) Into 70 ml of dry pyridine, 10.0 g of commercially available active amyl alcohol [(-)-2-methyl-butanol] was put and cooled with ice. After that, 33.2 g of p-toluenesulfonic acid chloride was slowly added. After adding p-toluenesulfonic acid chloride, the mixture was allowed to react overnight while slowly returning to room temperature. After the reaction was completed, the insoluble matter was separated and the solution was extracted with ether. The organic layer was washed with 2N hydrochloric acid and saturated brine, dried, and the organic solvent was distilled off under reduced pressure to obtain 33.6 g of oily p-toluenesulfonic acid 2-methylbutyl ester.

(Ii) 5.4 g of metallic sodium was added to 120 ml of dry ethanol to synthesize an alcoholate. Diethyl malonate was slowly added dropwise to this ethanol solution at room temperature. Thirty minutes after the completion of dropping, a solution of p-toluenesulfonic acid 2-methylbutyl ester obtained in (i) dissolved in 20 ml of dry ethanol was slowly added dropwise at room temperature. After completion of the dropping, the mixture was further reacted under reflux for 18 hours, the precipitate was separated, ethanol was distilled off, and the mixture was extracted with ether. The organic layer was washed with water and saturated saline, dried and then the ether was removed. The obtained oily substance was distilled under reduced pressure to give 2-methylbutyl malonic acid diethyl ester (boiling point: 101-103 ° C / 4mmHg) 50g
Got

(Iii) 50 g of 2-methylbutylmalonic acid diethyl ester was added dropwise to 100 ml of 50% aqueous potassium hydroxide solution at room temperature. After the dropping, the mixture was further reacted under reflux for 2 hours, and the produced ethanol was distilled off. After collecting ethanol, the mixture was cooled, and 100 g of concentrated sulfuric acid and 150 ml of water were carefully added to the mixture under ice cooling while vigorously stirring. After adding over 40 minutes, the mixture was heated under reflux for 3 hours. After cooling, the mixture was extracted with ether, washed with saturated brine and dried, and then the organic solvent was distilled off under reduced pressure to obtain an oily substance. This was distilled under reduced pressure to obtain 11.5 g of 4-methylhexanoic acid (boiling point: 100 to 102 ° C / 4 mmHg).

(Iv) 3.8 g of lithium aluminum hydride was added to 100 ml of dry ether, and 10.0 g of 4-methylhexanoic acid dissolved in 20 ml of dry ether was added dropwise under ice cooling. After the dropping, the mixture was further reacted at room temperature for 17 hours, the reaction mixture was decomposed with ice water and dilute hydrochloric acid under ice cooling, and this was extracted with ether. The organic layer was washed with 1N aqueous sodium hydroxide, water, and saturated saline, dried, and then the ether was removed, followed by vacuum distillation to obtain optically active 4-methylhexanol (boiling point: 170 to 172).
℃) 8.5g was obtained.

(V) 2.5 g of p-iodobenzoic acid and 5 ml of thionyl chloride were heated under reflux for 6 hours to distill off excess thionyl chloride,
p-Iodobenzoic acid chloride was obtained. This product was not particularly purified and used as a toluene solution in the next step. on the other hand,
Optically active 4-methylhexanol (1.1 g) and pyridine (0.8 g) dissolved in toluene (20 ml) was ice-cooled, and the above solution of acid chloride in toluene was added dropwise to the solution with stirring for about 30 minutes. The mixture was stirred on the hot water bath for 5 hours. After cooling, add 6N hydrochloric acid and water to acidify, separate the layers and collect the organic layer.
After washing with water, washing with saturated aqueous sodium hydrogen carbonate, and washing with water, the toluene was removed under reduced pressure, and the hexane-soluble portion was purified with a silica gel column to obtain 2.9 g of optically active p-iodobenzoic acid-4-methylhexyl ester. It was

(3) Synthesis of compound No. 2 in Table-1 1.4 g of pn-decyloxy-m-fluorophenylacetylene was dissolved in 20 ml of triethylamine together with 1.8 g of optically active p-iodobenzoic acid-4-methylhexyl ester. Then, after substituting with nitrogen, 19 mg of copper (I) iodide and 35 mg of dichlorobis (triphenylphosphine) palladium (II) were added, and the mixture was stirred for 24 hours, then poured into water and extracted with 100 ml of ether. The extract was washed with diluted hydrochloric acid and water, dried and then the ether was distilled off. After dissolving in hexane and passing through a short column of activated alumina, distilling off hexane and recrystallizing from ethanol, 1.3 g of compound No. 2 in Table-1 [yield 53%, pn-decyloxy- m-Fluorophenyl) acetylene standard]
Got

Example 3 (1) Synthesis of 4-methylhexanol (i) 10.0 g of commercially available active amyl alcohol [(-)-2-methyl-butanol] was put in 70 ml of dry pyridine, and after ice-cooling, p-chloride was added. Toluenesulfonic acid 33.2 g was added slowly. After adding p-toluenesulfonic acid chloride, the mixture was allowed to react overnight while slowly returning to room temperature. After the reaction was completed, the insoluble matter was separated and the solution was extracted with ether. The organic layer was washed with 2N hydrochloric acid and saturated brine, dried, and the organic solvent was distilled off under reduced pressure to obtain 33.6 g of oily p-toluenesulfonic acid 2-methylbutyl ester.

(Ii) 5.4 g of metallic sodium was added to 120 ml of dry ethanol to synthesize an alcoholate. Diethyl malonate was slowly added dropwise to this ethanol solution at room temperature. Thirty minutes after the completion of dropping, a solution of p-toluenesulfonic acid 2-methylbutyl ester obtained in (i) dissolved in 20 ml of dry ethanol was slowly added dropwise at room temperature. After the dropping is completed,
After reacting for 18 hours under reflux and separating the precipitate,
Ethanol was distilled off, and extracted with ether. The organic layer was washed with water and saturated saline, dried and then the ether was removed. The obtained oily substance was distilled under reduced pressure to give 2-methylbutyl malonic acid diethyl ester (boiling point: 101-103 ° C / 4mmHg) 50g
Got

(Iii) 50 g of 2-methylbutylmalonic acid diethyl ester was added dropwise to 100 ml of 50% aqueous potassium hydroxide solution at room temperature. After the dropping, the mixture was further reacted under reflux for 2 hours, and the produced ethanol was distilled off. After collecting ethanol, the mixture was cooled, and 100 g of concentrated sulfuric acid and 150 ml of water were carefully added to the mixture under ice cooling while vigorously stirring. After adding over 40 minutes, the mixture was heated under reflux for 3 hours. After cooling, it was extracted with ether, washed with saturated brine, dried, and the organic solvent was evaporated under reduced pressure to give an oil. This was distilled under reduced pressure to obtain 11.5 g of 4-methylhexanoic acid (boiling point: 100 to 102 ° C / 4 mmHg).

(Iv) 3.8 g of lithium aluminum hydride was added to 100 ml of dry ether, and 10.0 g of 4-methylhexanoic acid dissolved in 20 ml of dry ether was added dropwise under ice cooling. After the dropping, the mixture was further reacted at room temperature for 17 hours, the reaction mixture was decomposed with ice water and dilute hydrochloric acid under ice cooling, and this was extracted with ether. The organic layer was washed with 1N aqueous sodium hydroxide, water and saturated saline,
After drying and removing the ether, it was distilled under reduced pressure to obtain 4-methylhexanol (boiling point: 170 to 17).
2 ° C.) 8.5 g was obtained.

(2) Synthesis of optically active 4-iodo-4'-biphenylcarboxylic acid 4-methylhexyl ester 3.3 g of 4-iodo-4'-biphenylcarboxylic acid and 10 ml of thionyl chloride were heated under reflux for 6 hours. Then, excess thionyl chloride was distilled off to obtain 4-iodo-4'-biphenylcarboxylic acid chloride. This product was not particularly purified and used as a toluene solution in the next step.

On the other hand, 1.1 g of optically active 4-methylhexanol and pyridine
A solution obtained by dissolving 0.8 g in 20 ml of toluene was ice-cooled, and the toluene solution of the above acid chloride was added dropwise thereto with stirring for about 30 minutes, and further stirred on a water bath at 90 ° C. for 5 hours. After cooling
The mixture was acidified by adding 6N hydrochloric acid and water, the organic layer was separated, washed with water, washed with saturated aqueous sodium hydrogen carbonate, washed with water, and then toluene was removed under reduced pressure. Optically active 4-iodo-
3.8 g of 4'-biphenylcarboxylic acid 4-methylhexyl ester was obtained.

(3) Synthesis of compound No. 3 in Table-1 pn-decyloxy-synthesized in the same manner as in Example 2
1.4 g of m-fluorophenylacetylene was dissolved in 40 ml of triethylamine together with 2.1 g of optically active 4-iodo-4′-biphenylcarboxylic acid 4-methylhexyl ester, and after nitrogen substitution, copper (I) iodide 38 mg, dichlorobis ( 70 mg of triphenylphosphine) palladium (II) was added, and the mixture was stirred for a day and night, then poured into water and extracted with 100 ml of toluene. The extract was washed with diluted hydrochloric acid and water, dried and the toluene was distilled off. It was dissolved in toluene, passed through a short column of activated alumina, and the toluene was distilled off, followed by recrystallization from ethanol. The compound No. 3 in Table 1 was 2.3 g (yield 80%, pn-decyloxy-m-). Fluorophenylacetylene standard) was obtained.

Table 2 shows the phase transition temperatures of the compounds obtained in Examples 1 to 3 and conventional tolan compounds. In addition, the following compounds (JP
62-228043) is also shown as a comparative example.

In Table 2, each symbol has the following meaning.

C: Crystal phase S ₁ : Unidentified smectic phase Sc ^* : Chiral smectic C phase S _A : Smectic A phase Ch: Cholesteric phase I: Isotropic liquid phase Sc ^* phase temperature range of the compound of Comparative Example is 39.5-40 ° C Which is a compound of the present invention (for example, the compound of Example 1) Has a very wide Sc ^* phase temperature range of -2.8 to 38.2 ° C and is a very excellent liquid crystal compound.

Examples 4 and 5 The compounds of Examples 1 and 3 and known smectic liquid crystal compounds (the following compounds A and B) were mixed in the proportions shown in Table 3 to obtain liquid crystal compositions of the present invention.

The liquid crystal compounds shown in Table 3 were weighed in predetermined weights, and the four compounds were heated in a sample bottle and mixed while being dissolved. This is a very useful liquid crystal composition which exhibits a chiral smectic C phase in a wide temperature range including room temperature as shown in Table 3 and is chemically stable.

Compound A: Optically active 4-n-octyloxy-4'-biphenylcarboxylic acid-2-methylbutyl ester Compound B: Optically active 4-n-octyloxy-4'-biphenylcarboxylic acid-4- (2-methyl) Butyloxycarbonyl) phenyl ester Example 6 A liquid crystal composition having the following composition was prepared using the liquid crystal compounds of the present invention of Sample Nos. 1 and 2 in Table 1 above and other liquid crystal compounds.

The compound of (Note 1) was synthesized by the same method as in Example 1.
The liquid crystal composition was prepared in the same manner as in Examples 4 and 5.

Polyvinyl alcohol was applied as an alignment treatment agent, and the obtained composition was injected into a cell having a cell thickness of 2 μm provided with a transparent electrode which was rubbed on the surface and subjected to parallel alignment treatment to prepare an optical switching element. This element was placed between two orthogonal polarizers and an electric field was applied. When the response time is calculated from the change in the transparent intensity due to the application of 20V, it is about 300 at 25 ℃.
It was μsec.

When the temperature change of the texture of the liquid crystal composition was examined by a polarization microscope, it was found that it became a ferroelectric liquid crystal in the temperature range of 10 ° C to 53 ° C, and the magnitude of spontaneous polarization thereof was 25 ° C. It was 10 nC / cm ² and the tilt angle was 24 °.

[Effect of the Invention] The liquid crystal compound and the liquid crystal composition of the present invention have the following remarkable effects.

(1) It is an epoch-making material in obtaining a practical ferroelectric liquid crystal with a wide temperature range in which the chiral smectic phase exhibiting ferroelectricity is exhibited at room temperature.

(2) Good stability against light, heat and moisture.

(3) The response is as fast as or higher than that of a conventional liquid crystal composition exhibiting ferroelectricity.

[Brief description of drawings]

FIG. 1, FIG. 2 and FIG. 3 show the infrared absorption spectrum, H-NMR spectrum and F-NMR spectrum of the compound obtained in Example 1, respectively.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kishiki 1-11, 1 Hitotino-honcho, Higashiyama-ku, Kyoto-shi, Kyoto Prefecture Sanyo Chemical Industry Co., Ltd. No. 1 Sanyo Chemical Industry Co., Ltd. (72) Inventor Hiroshi Hayashi 11-11, Hitotsubashi Honcho, Higashiyama-ku, Kyoto City, Kyoto Prefecture No. 1 Sanyo Chemical Co., Ltd. No. 1 Inside NEC Corporation (72) Inventor Yuji Kato 5-33-1 Shiba, Minato-ku, Tokyo No. 1 Inside NEC Corporation (72) Shohei Naemura 5-33-1 Shiba, Minato-ku, Tokyo No. Nippon Electric Co., Ltd. (72) Inventor Hideo Ichinose 5-33-1 Shiba, Minato-ku, Tokyo NEC Electric Co., Ltd. (72) Inventor, Chizuka Tani 5-33-1, Shiba, Minato-ku, Tokyo Date Inside the Electric Company (56) References JP-A-63-284147 (JP, A)

Claims (5)

[Claims] 1. A general formula [In the formula, R is an alkyl group having 3 to 18 carbon atoms. X is-
It is 0- or a single bond (direct bond). A ₁ and A ₂ are F and C
l, -CN, an -NO ₂ and chosen from the group consisting of -CF ₃ optionally substituted with a substituent phenylene group or biphenylene group, A ₁ and A ₂ do not become a phenylene group at the same time. n is an integer of 2 to 7. R'is 2 to 2 carbon atoms
10 straight chain alkyl groups. In addition, ^* indicates that it is optically active. ] The tolan compound shown by these. 2. The compound according to claim 1, wherein X is -0-. 3. The compound according to claim 1, wherein the substituents of A ₁ and A ₂ are F. 4. The compound according to any one of claims 1 to 3, wherein R'is an ethyl group. 5. A general formula [In the formula, R is an alkyl group having 3 to 18 carbon atoms. X is-
It is 0- or a single bond (direct bond). A ₁ and A ₂ are F and C
l, -CN, an -NO ₂ and chosen from the group consisting of -CF ₃ optionally substituted with a substituent phenylene group or biphenylene group, A ₁ and A ₂ do not become a phenylene group at the same time. n is an integer of 2 to 7. R'is 2 to 2 carbon atoms
10 straight chain alkyl groups. In addition, ^* indicates that it is optically active. ] A liquid crystal composition exhibiting a chiral smectic phase, containing at least one compound represented by the formula [1] as a compounding component.