JPH0647572B2 - Liquid crystalline compound - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel liquid crystal compound, and more specifically, to an optically active liquid crystal compound, a chiral liquid crystal composition containing the same, and the liquid crystal composition. The present invention relates to a liquid crystal element.

BACKGROUND ART Conventional liquid crystal elements include, for example, M.Sc
hadt) and W. Helfrich,
"Applied Physics Letters", Vol.18, No.4, Vol.18, No.4 (19)
71.2.15), P.127-128, "Voltage-Dependent Optical Activities of Twisted Nematic Liquid Crystals".
It is known to use a TN (twisted nematic) liquid crystal described in "Tity of a Twisted Nematic Liquid Crystal". However, this TN liquid crystal is
Since there is a problem that crosstalk occurs when time-division driving using a matrix electrode structure with a high pixel density,
The number of pixels was limited. Further, since the electric field response is slow and the viewing angle characteristic is poor, the use as a display is limited.

Furthermore, a display element of a type in which a switching element using a thin film transistor is connected to each pixel and switching is performed for each pixel is known, but a process of forming a thin film transistor on a substrate is extremely complicated, and a large area display element is used. There are problems that are difficult to create.

The use of bistability-type liquid crystal elements is one of the ways to improve the drawbacks of the conventional type liquid crystal elements.
ark) and Lagerwall (JP-A-56-107216, US Pat. No. 4,367,924, etc.). As a liquid crystal having bistability, a chiral smectic C phase (SmC ^* ) or an H phase (Sm) is generally used.
A ferroelectric liquid crystal having H ^* ) is used.

Since this ferroelectric liquid crystal has spontaneous polarization, it has a very fast response speed, and can express a bistable state with a memory property, and also has excellent viewing angle characteristics. Suitable as

Further, conventionally, as an optically active intermediate for synthesizing a functional material required for an optical element having an optical activity, 2-methylbutanol, secondary octyl alcohol, secondary butyl alcohol, p-chloride -(2-Methylbutyl) benzoic acid, secondary phenethyl alcohol, amino acid derivatives, camphor derivatives, cholesterol derivatives and the like are known.

However, these have the following problems. The structure of the optically active chain hydrocarbon derivative is difficult to change, and, except for some, it is very expensive. Amino acid derivatives are relatively inexpensive and their structures can be easily modified, but the hydrogen groups of amines are chemically strongly active, and hydrogen bonding and chemical reactions are likely to occur, which tends to limit the properties of functional materials. . It is difficult to change the structure of camphor derivatives and cholesterol derivatives, and steric hindrance tends to adversely affect the properties of functional materials.

The above-mentioned drawbacks have been a major limitation in developing various materials.

OBJECT OF THE INVENTION The present invention has been made in view of the above points. That is, the present invention has a liquid crystal compound having a smectic liquid crystal phase at around room temperature or having an effect of lowering the temperature of a SmC ^* phase and expanding when mixed, a liquid crystal composition containing at least one thereof, and the liquid crystal composition. An object of the present invention is to provide a liquid crystal device using the.

In the present invention, it is easy to change the length of the alkyl group, which allows H. Arnold, “Zeit Schriftfür Physikalish Chemie” (Z. Phys. Chem.), 22.
Provided are a liquid crystal compound capable of controlling the type and temperature range of a liquid crystal phase developed in a liquid crystal state as shown in 6,146 (1964) and a liquid crystal composition containing at least one compounding component thereof. The purpose is to Also LB
An object of the present invention is to provide a compound capable of easily controlling a hydrophobic group and stably forming a film when a monomolecular cumulative film is produced by the (Langmuir-Blodgett) film method.

SUMMARY OF THE INVENTION That is, the present invention provides a compound represented by formula (I) (Here, R ₁ is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and R ^* is 4 carbon atoms having an asymmetric carbon atom.
To 12 alkyl groups, 1 = 1 or 2, m
= 0 or 1. The present invention provides a liquid crystal compound represented by

The present invention also provides a liquid crystal composition containing at least one kind of the above-mentioned optically active liquid crystalline compound as a component, and a liquid crystal element using the liquid crystal composition.

Detailed Description of the Invention In the liquid crystal compound of the above general formula (I), it is possible to control the type and temperature range of the liquid crystal phase to be developed by adjusting the carbon number of R ₁ , and the carbon number of 1 to 1 18
It is possible to use those having 4 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, and the viscosity and S
It is selected in terms of the temperature range of the mC ^* phase.

The liquid crystal compound represented by the general formula (I) is preferably synthesized from an optically active 4-alkoxybenzenethiol represented by the following general formula (II) as shown in the specification of Japanese Patent Application No. 60-193831. To be done.

(R ^* is an alkyl group having an asymmetric carbon atom and having 4 to 12 carbon atoms) Specific examples of the optically active 4-alkoxybentiol include the following.

(+)-4- (2'-Methyl-butoxy) benzenethiol, (+)-4- (1'-methyl-propoxy) benzenethiol, (-)-4- (1'-methyl-propoxy) benzenethiol , (+)-4- (1'-methylhexyloxy) benzenethiol, (-)-4- (1 '
-Methylhexyloxy) benzenethiol, (+)-
4- (1'-methylpentyloxy) benzenethiol, (-)-4- (1'-methylpentyloxy) benzenethiol, (+)-4- (1 ', 3'-dimethylpropoxy) benzenethiol, ( -)-4- (1 ',
3'-dimethylpropoxy) benzenethiol, (+)
-4- (1'-methylheptyloxy) benzenethiol, (-)-4- (1'-methylheptyloxy) benzenethiol, (+)-4- (1'-methylbutoxy)
Benzenethiol, (−)-4- (1′-methylbutoxy) benzenethiol, (+)-4- (3′-methylpentyloxy) benzenethiol, (−)-4- (2 ′)
-Methyloctyloxy) benzenethiol, (-)-
4- (2'-methylnonyloxy) benzenethiol,
(−)-4- (2′-methyldecyloxy) benzenethiol, (+)-4- (4′-methylhexyloxy)
Benzenethiol.

For example, the liquid crystalline compound of the present invention can be obtained from these optically active 4-alkoxybenzenethiols by the following synthetic route.

(Here, R ₁ , l and R ^* have the same meanings as above.) Specific examples of the liquid crystal compound thus obtained are as follows.

4-n-hexyloxythiobenzoic acid-S-4 '-(2
-Methylbutyloxy) phenyl, 4-n-heptyloxythiobenzoic acid-S-4 '-(2-methylbutyloxy) phenyl, 4-n-octyloxythiobenzoic acid-
S-4 '-(2-methylbutyloxy) phenyl, 4-
n-nonyloxythiobenzoic acid-S-4 '-(2-methylbutyloxy) phenyl, 4-n-decyloxythiobenzoic acid-S-4'-(2-methylbutyloxy) phenyl, 4-n- Dodecyloxythiobenzoic acid-S-4 '
-(2-Methylbutyloxy) phenyl, 4-n-hexadecyloxythiobenzoic acid-S-4 '-(2-methylbutyloxy) phenyl, 4-n-hexylthiobenzoic acid-S-4'-(2 -Methylbutyloxy) phenyl,
4-n-decylthiobenzoic acid-S-4 '-(2-methylbutyloxy) phenyl, 4-n-tridecylthiobenzoic acid-S-4'-(2-methylbutyloxy) phenyl, 4'-n-hexyl Oxybiphenylthiocarboxylic acid-S-4- (2-methylbutyloxy) phenyl,
4'-n-octyloxybiphenylthiocarboxylic acid-
S-4- (2-methylbutyloxy) phenyl, 4'-
n-decyloxybiphenylthiocarboxylic acid-S-4-
(2-Methylbutyloxy) phenyl, 4'-n-heptylbiphenylthiocarboxylic acid-S-4- (2-methylbutyloxy) phenyl, 4-n-hexyloxybenzoic acid-4'-thiocarboxylic acid phenyl-S- 4 ″-(2
-Methylbutyloxy) phenyl, 4-n-decyloxybenzoic acid-4'-thiocarboxylic acid phenyl-S-4 "
-(2-methylbutyloxy) phenyl, 4-n-dodecyloxybenzoic acid-4'-thiocarboxylic acid phenyl-
S-4 ″-(2-methylbutyloxy) phenyl, 4-
n-decylbenzoic acid-4'-thiocarboxylic acid phenyl-
S-4 ″-(2-methylbutyloxy) phenyl, 4-
n-Pentyloxythiobenzoic acid-S-4 '-(3-methylpentyloxy) phenyl, 4-n-hexyloxythiobenzoic acid-S-4'-(3-methylpentyloxy) phenyl, 4-n- Octyloxythiobenzoic acid-
S-4 '-(3-methylpentyloxy) phenyl, 4
-N-decyloxythiobenzoic acid-S-4 '-(3-methylpentyloxy) phenyl, 4-n-hexylthiobenzoic acid-S-4'-(3-methylpentyloxy) phenyl, 4'-n- Octyloxybiphenylthiocarboxylic acid-S-4- (3-methylpentyloxy) phenyl, 4-n-hexyloxythiobenzoic acid-S-4'-
(4-methylhexyloxy) phenyl, 4-n-decyloxythiobenzoic acid-S-4 '-(4-methylhexyloxy) phenyl, 4-n-heptylthiobenzoic acid-
S-4 '-(4-methylhexyloxy) phenyl, 4
-N-hexyloxythiobenzoic acid-S-4 '-(1-
Methylpropoxy) phenyl, 4-n-decyloxythiobenzoic acid-S-4 '-(1-methylpropoxy) phenyl, 4-n-octyloxythiobenzoic acid-S-4'
-(1-Methylhexyloxy) phenyl, 4-n-dodecyloxythiobenzoic acid-S-4 '-(1-methylpentyloxy) phenyl, 4-n-hexylthiobenzoic acid-S-4'-(1- Methylpentyloxy) phenyl, 4-n-octyloxythiobenzoic acid-S-4'-
(1,3-Dimethylpropoxy) phenyl, 4-n-tridecyloxythiobenzoic acid-S-4 '-(1,3-Dimethylpropoxy) phenyl, 4-n-heptyloxythiobenzoic acid-S-4' -(1-Methylheptyloxy) phenyl, 4-n-octyloxythiobenzoic acid-
S-4 '-(1-methylheptyloxy) phenyl, 4
-N-hexyloxythiobenzoic acid-S-4 '-(1-
Methylbutoxy) phenyl, 4-n-heptyloxythiobenzoic acid-S-4 '(1-methylbutoxy) phenyl, 4-n-hexylthiobenzoic acid-S-4'-(1-
Methylbutoxy) phenyl, 4-n-octyloxythiobenzoic acid-S-4 '-(2-methyloctyloxy)
Phenyl, 4-n-decyloxythiobenzoic acid-S-
4 '-(2-methylnonyloxy) phenyl, 4-n-
Heptyloxythiobenzoic acid-S-4 '-(2-methyldecyloxy) phenyl, 4-n-pentylthiobenzoic acid-S-4'-(2-methyldecyloxy) phenyl,
4'-n-hexyloxybiphenylthiocarboxylic acid-
S-4- (2-methyldecyloxy) phenyl.

Table 1 shows examples of the liquid crystal compounds thus obtained.

In the table, the symbols in the column of phase transition temperature indicate the following phases, respectively.

Gryst .: Crystal phase, SmA: Smectic A phase, SmC ^* : Chiral smectic C phase, N: Nematic phase, Ch .: Cholesteric phase, Iso: Isotropic phase, Sm1, Sm2: SmA, smectic phase other than SmC ^* ( Unidentified).

The liquid crystal composition of the present invention contains at least one liquid crystal compound represented by the general formula (I) as a blending component. For example, when the liquid crystal compound represented by the general formula (I) is combined with a ferroelectric liquid crystal represented by the following formulas (1) to (13), SmC ^* can be lowered and the temperature range can be expanded. It will be possible.

In such a case, the liquid crystal compound of the present invention represented by the general formula (I) is added to the obtained liquid crystal composition in an amount of 1 to 99%.
It is preferable to use it in an amount of 5% by weight, particularly 5 to 95% by weight.

(1) 4-octyloxybenzoic acid 4 '-(2-methylbutyloxy) phenyl ester (2) 4-nonyloxybenzoic acid 4 '-(2-methylbutyloxy) phenyl ester (3) 4-decyloxybenzoic acid 4 '-(2-methylbutyloxy) phenyl ester (Four) 4-Undecyloxybenzoic acid 4 '-(2-methylbutyloxy) phenyl ester (Five) 4-dodecyloxybenzoic acid 4 '-(2-methylbutyloxy) phenyl ester (6) 4-decyloxybenzoic acid 4 '-(2-methoxypropyloxy) phenyl ester (7) 4,4'-azoxycinnamic acid-bis (2-methylbutyl) ester (8) 4-o- (2-methyl) -butylresorcylidene-4 '
-Octylaniline (MBRA 8) (9) 4- (2'-methylbutyl) phenyl-4'-octyloxybiphenyl-4-carboxylate (Ten) 4-hexyloxyphenyl-4- (2 "-methylbutyl) biphenyl-4'-carboxylate (11) 4-octyloxyphenyl-4- (2 "-methylbutyl) biphenyl-4'-carboxylate (12) 4-heptylphenyl-4- (4 "-methylhexyl)
Biphenyl-4'-carboxylate (13) 4- (2 "-methylbutyl) phenyl-4- (4" -methylhexyl) biphenyl-4'-carboxylate Further, a composition that can be used as a ferroelectric liquid crystal can be obtained by blending with a smectic liquid crystal which is not chiral itself as shown in the following formulas (14) to (18).

In this case, 1 to 99% by weight, particularly 5 to 9% by weight of the liquid crystal composition from which the liquid crystalline compound of the present invention represented by formula (I) can be obtained.
It is preferably used at 5% by weight.

(14) (4-nonyloxyphenyl) -4'-octyloxybiphenyl-4-carboxylate (15) 4,4'-decyloxyazoxybenzene (16) 2- (4'-hexyloxyphenyl) -5- (4-hexyloxyphenyl) pyrimidine (17) 2- (4'-octyloxyphenyl) -5-nonylpyrimidine (18) 4'-Pentyloxyphenyl-4-octyloxybenzoate Here, the symbols indicate the following phases, respectively.

Gryst .: Crystal phase, SmA: Smectic A phase, SmB: Smectic B phase, SmC: Smectic C phase, N: Nematic phase, Iso .: Isotropic phase.

EFFECTS OF THE INVENTION The liquid crystalline compound represented by the general formula (I) of the present invention can be easily derived from the above-mentioned 4- (alkoxy) benzenethiol, exhibits the SmC ^* phase at a relatively low temperature, and has a wide temperature range. Since it exhibits a stable SmC ^* phase, it is effective when used as a ferroelectric liquid crystal device material. Further, the liquid crystal composition containing at least one liquid crystalline compound represented by the general formula (I) of the present invention can expand the temperature range of the SmC ^* phase while lowering the temperature, and is effective in improving the characteristics. is there.

Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 S-4 '-(2-Methylbutyloxy) phenyl 4-octyloxythiobenzoate.

4-octyloxybenzoic acid 4.0 g (1.6 × 10 ^-2
20 m of SOCl ₂ was added to (mol) and heated under reflux for 4 hours. It was added 4-octyloxy benzoic acid chloride was distilled off the excess SOCl _2.

4- (2'-methylbutyloxy) benzenethiol 3.136 g (1.6 × 10 ^-2 mol) and pyridine 1.2
After dissolving 46 g in 12 m of toluene and cooling with ice, 4-octyloxybenzoic acid chloride dissolved in 10 m of toluene was added dropwise. Then, the mixture was stirred at room temperature for 3.5 hours.

The reaction mixture was poured into cold water, acidified with 6N HCl solution and the precipitated crystals were filtered off. The organic layer is water, 2NNaO
The solution was washed with H solution and water, dried over anhydrous NaSO ₄ , and the solvent was distilled off to obtain 7.9 g of an oily substance.

Purification by silica gel column chromatography and recrystallization from ethanol gave 2.3144 g of S-4 ′-(2-methylbutyloxy) phenyl 4-octyloxythiobenzoate. 33.8%.

The following IR and NMR data were obtained on the product.

IR (cm ^-1 ): 2930, 2870, 1675, 1605, 1500, 1475, 1265, 1250, 1170, 905, 840.

NMR ([sigma] ppm): 8.1-6.8 (8H), 4.2-3.7 (4H), 2.0-0.9 (24H).

Examples 2 and 6 to 9 By the same method as in Example 1, liquid crystal compounds of the present invention were obtained. The products are listed in Table 1 above along with their phase transition temperatures.

Example 3 4'-octyloxybiphenylthiocarboxylic acid S-4
-(2'-Methylbutyloxy) phenyl.

4-octyloxybiphenylcarboxylic acid 4.0 g
SOCl ₂ 20m was added to (1.23 × 10 ^-2 mol),
The mixture was heated under reflux for 5 hours to synthesize 4'-octyloxybiphenylcarboxylic acid chloride.

4- (2'methylbutyloxy) benzenethiol 2.
41 g (1.23 × 10 ^-2 mol) and 972 mg of pyridine were dissolved in 12 m of toluene, and the mixture was ice-cooled to 12 m of toluene.
4'-octyloxybiphenylcarboxylic acid chloride dissolved in was added dropwise. Then, it stirred at room temperature for 6 hours.

The reaction mixture was extracted into cold water, acidified with 6N HCl solution, and the precipitated crystals were filtered off. The organic layer is water, 2NNa
It was washed with an OH solution and water in that order, dried over anhydrous NaSO ₄ , and then the solvent was distilled off to obtain 8.5 g of an oily substance.

This oily substance was purified by column chromatography,
1.6 g of crystals were obtained.

Further, it was purified by column chromatography with n-hexane: MeOH = 50: 1 and recrystallized from ethanol to give 898 g of 4 '.
-Octyloxybiphenylthiocarboxylic acid S-4-
(2'-Methylbutyloxy) phenyl was obtained.

The following IR and NMR data were obtained on the product.

IR (cm ^-1 ): 2925, 2850, 1670, 1600, 1500, 1250, 1190, 910, 830.

NMR ([sigma] ppm): 8.1 to 6.8 (12H), 4.1 to 3.7 (4H), 2.1 to 0.9 (24H).

Examples 4, 5 By the same method as in Example 3, liquid crystal compounds of the present invention were obtained. The products, together with their phase transition temperatures, are as shown in Table 1 above.

Example 10 p-Dodecyloxybenzoic acid phenyl p'-thiocarboxylic acid.

Sp "(2-methylbutyloxy) phenyl 4.0 g of p-dodecyloxybenzoic acid (1.31 x 10
^-2 mol) was dissolved in benzene 15 m, PC1 ₅ 2.79
g (1.31 × 10 ^-2 mol) was added little by little with stirring at room temperature. Then, the mixture was heated under reflux for 3 hours and the solvent was distilled off to obtain 4.4 g of p-dodecyloxybenzoic acid chloride.

p-Acetyloxybenzoic acid (5.56 × 10 ^-2 mol)
Is dissolved in 45 m of benzene, and PC1 ₅ 11.8 g
(5.56 × 10 ^-2 mol) was added at room temperature every 5 minutes in 6 batches. After stirring for 20 minutes at room temperature, the mixture was heated under reflux and stirred for 5 hours.

The solvent was distilled off to obtain 12.7 g of a pale yellow oily substance, p-acetyloxybenzoic acid chloride.

4-amyloxybenzenethiol 10.7 g (5.0
4 × 10 ^-2 mol) and pyridine 3.98 g (5.04)
X10 ^-2 mol) was dissolved in 30 m of toluene, and 12.7 g of a solution of 30 m of toluene was added dropwise at 50C over 50 minutes. Then, the mixture was stirred at room temperature for 8 hours.

After completion of the reaction, the reaction mixture was extracted into cold water to obtain 6N-HC
The solution was acidified with 1 solution and the precipitated crystals were separated. The organic layer was washed successively with water, 2N-NaOH solution and water, dried over anhydrous Na ₂ SO ₄ and the solvent was distilled off to give 19.0 g of a pale yellow oil (phenyl p′-acetyloxythiocarboxylate). Sp "(2-methylbutyloxy) phenyl)
Got

To the phenyl S-p ″ (2-methylbutyloxy) phenyl p′-acetyloxythiocarboxylate obtained above, 50 m of methanol was added and dissolved. Methanol / N was added to this.
H ₄ OH (28%) = 1/1 was added with stirring.

Put in 150m of water and extract 3 times with 100m of ether,
The ether layer was washed 3 times with 100 m of water. Anhydrous Na ₂
After drying with SO ₄ , the solvent was distilled off to obtain 15.3 g of phenyl S-p ″ (2-methylbutyloxy) phenyl p-hydroxythiocarboxylate.

Phenyl S p-hydroxythiocarboxylate obtained above
-P "(2-methylbutyloxy) phenyl 3.71 g
(1.31 × 10 ^-2 mol) and 1.034 g of pyridine
(1.31 × 10 ^-2 mol) was dissolved in 17 m of toluene, and 4.4 g of decyloxybenzoic acid chloride was added at 9 ° C.
12 m toluene solution of was added dropwise over 20 minutes. Then, the mixture was stirred at room temperature for 20 hours.

After completion of the reaction, the reaction mixture was extracted into cold water, acidified with 6N HCl solution, and the precipitated crystals were separated. The organic layer was washed with water, 2N NaOH solution and water, and dried over anhydrous Na ₂ SO ₄
After drying in, the solvent was distilled off to obtain 3.5 g of a crude product.

Column chromatography purification was performed to obtain 3.1 g of crystals. This was recrystallized from ethanol and further from ethyl acetate to give 1.1 g of p-dodecyloxybenzoic acid p'-.
Phenylthiocarboxylate Sp- (2-methylbutyloxy) phenyl was obtained.

The following IR and NMR data were obtained on the product.

IR (cm ^-1 ): 3930, 3855, 1740, 1685, 1620, 1600, 1500, 1475, 1265, 1210, 1170, 1070, 910.

NMR (δ ppm): 8.2-6.7 (12H), 4.2-3.7 (4H), 2.1-0.9 (32H).

Example 11 In the same manner as in Example 10, p-decylbenzoic acid p ′ was used.
-Phenylthiocarboxylate Sp- (2-methylbutyloxy) phenyl was synthesized.

The following IR and NMR data were obtained on the product.

IR (cm ^-1 ): 2930, 2860, 1745, 1665, 1600, 1500, 1275, 1250, 1220, 1165, 1075, 910.

NMR (σppm): 8.3 to 6.9 (12H), 3.6 to 4.1 (d, 2H), 2.6 to 3.0 (t, 2H), 2.0 to 0.9 ( 28H).

Example 12 4-Octyloxybenzoic acid 4 '-(2-methylbutyloxy) phenyl ester (A below), which is a known ferroelectric liquid crystal compound, and 4 obtained according to Example 2 of the present invention.
-Decyloxythiobenzoic acid S-4 '-(2-methylbutyloxy) phenyl ester (B below) was mixed. Changes in the phase transition temperature of the obtained liquid crystal composition depending on the composition are shown as phase diagrams in the accompanying drawings.

Example 13 Liquid crystal device using the liquid crystal composition produced in Example 12 An ITO film of about 1000 Å was provided as an electrode on a glass of 10 × 20 mm which was highly precision polished, and further about 1000 Å of Si was provided.
O ₂ was deposited by the ion beam method. The liquid crystal composition produced in Example 12 was dropped on a glass substrate processed in the same manner, and the above glass substrates were stacked facing each other. 63 ° C
When the substrates were held in place and the parallel movements were performed under a polarizing microscope while keeping the space between the upper and lower substrates so that they were offset from each other, horizontally oriented monodomains in which the helical structure disappeared were obtained. Liquid crystal layer thickness at that time is 1.2μ
m, and when a pulse of ± 20 V was applied at 50 ° C., switching was performed in about 1 msec.

At this time, a uniaxial orientation treatment such as a rubbing treatment may be performed as an orientation control method.

[Brief description of drawings]

The drawings are phase diagrams showing the phase transition temperatures of liquid crystal compounds of the present invention and liquid crystal compositions containing the same prepared according to Examples 2 and 12 with respect to the compositions.

Claims (26)

[Claims] 1. The following general formula (I): (Here, R ₁ is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and R ^* is 4 carbon atoms having an asymmetric carbon atom.
To 12 alkyl groups, 1 = 1 or 2, m
= 0 or 1. ) A liquid crystal compound represented by: 2. R ^* is 3-methylpentyl, 4-methylhexyl, 1-methylheptyl, 2-methylbutyl, 2-
The liquid crystal compound according to claim 1, which is methyloctyl, 2-methylnonyl or 2-methyldecyl. 3. The liquid crystalline compound according to claim 1, which undergoes a phase transition from an isotropic phase to a cholesteric phase and a chiral smectic C phase in this order during the temperature lowering process. 4. Smectic A in order from the isotropic phase during the cooling process.
The liquid crystalline compound according to claim 1, which undergoes a phase transition into a phase and a chiral smectic C phase. 5. The liquid crystal compound according to claim 1, which undergoes a phase transition from an isotropic phase to a cholesteric phase, a smectic A phase and a chiral smectic C phase in the order of decreasing the temperature. 6. The liquid crystalline compound according to claim 1, wherein a crystalline phase is formed next to the chiral smectic C phase in the temperature lowering process. 7. The liquid crystalline compound according to claim 1, which is 8. The liquid crystalline compound according to claim 1, which is 9. The liquid crystalline compound according to claim 1, which is 10. The liquid crystalline compound according to claim 1, which is 11. The liquid crystalline compound according to claim 1, which is 12. The method according to claim 12, The liquid crystalline compound according to claim 1, which is 13. The liquid crystalline compound according to claim 1, which is 14. The liquid crystalline compound according to claim 1, which is 15. The liquid crystalline compound according to claim 1, which is 16. The liquid crystalline compound according to claim 1, which is 17. The liquid crystalline compound according to claim 1, which is 18. The following general formula (I) (Here, R ₁ is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and R ^* is 4 carbon atoms having an asymmetric carbon atom.
To 12 alkyl groups, 1 = 1 or 2, m
= 0 or 1. ) A liquid crystal composition containing at least one liquid crystal compound represented by 19. The liquid crystal composition according to claim 18, which undergoes phase transitions from an isotropic phase to a cholesteric phase and a smectic A phase in the order of decreasing the temperature. 20. The liquid crystal according to claim 18, which contains at least one liquid crystal compound represented by the general formula (I) and at least one liquid crystal compound having an ester bond as compounding ingredients. Composition. 21. R ^* is 3-methylpentyl, 4-methylhexyl, 1-methylheptyl, 2-methylbutyl, 2
19. The liquid crystal composition according to claim 18, which is -methyloctyl, 2-methylnonyl or 2-methyldecyl. 22. A liquid crystal device, in which a liquid crystal composition containing at least one liquid crystal compound represented by the following general formula (I) as a compounding component is arranged between a pair of substrates. (Here, R ₁ is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, R ^* is an alkyl group having 4 to 12 carbon atoms having an asymmetric carbon atom, and l = 1 or 2,
m = 0 or 1). 23. The liquid crystal composition comprises chiral smectic C.
23. The liquid crystal element according to claim 22, which is in phase with each other. 24. The liquid crystal device according to claim 23, wherein the film thickness of the liquid crystal composition under the chiral smectic C phase is set to be sufficiently thin to eliminate the helical structure. 25. The liquid crystal device according to claim 22, wherein at least one of the substrates is subjected to a uniaxial alignment treatment. 26. The liquid crystal device according to claim 25, wherein the uniaxial alignment treatment is a rubbing treatment.