JP2692821B2 - Liquid crystal compound, production thereof and composition thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid crystal compound, a method for producing the same, and a liquid crystal composition containing the same. The liquid crystalline compound obtained in the present invention is used as a main component of a functional material constituting an optical element by mixing it with a chemically active ferroelectric liquid crystal compound. [Prior Art] A ferroelectric liquid crystal compound having optical activity is a compound expected as various optical elements such as a display element and a modulation element. Conventionally, an optically active liquid crystalline compound has been used as a main component of a functional material forming an optical element or as a relatively small amount but an important functional component. It has been shown that a display device having high-speed switching characteristics and a memory function can be realized by sandwiching and aligning such a compound in a thin cell having a thickness of several μm (Clark and Lagerwall, Applied Physical Letter, 36, 899). Page (1980)). [Problems to be Solved by the Invention] Conventional ferroelectric liquid crystal compounds and compositions have an insufficient temperature range showing SmC ^* (Chiral Smectic C phase) and are not sufficient. In addition, when a polycyclic compound is used in order to make the liquid crystal temperature range sufficient, there is a problem that the response speed is significantly reduced. [Means for Solving Problems] In view of the above-mentioned circumstances, the present inventors have obtained a compound represented by the following general formula (I) having a wide temperature range of the SmC ^* phase. General formula (I) Here, n is an integer of 1 to 10 and R ₁ and R ₂
Represents a liquid crystalline residue, and at least one of R ₁ and R ₂ has an optically active group. R ₁ and R ₂ are represented by the following general formula (II). BY _P AX _Q C- (where A is a mesogen group, B is a terminal flexible chain,
C is a spacer flexible chain. X and Y represent a bonding group, P and Q are each 1 and X and Y are
Is an ester bond, an ether bond, a thioester bond,
It is a bond selected from the group consisting of a thioester bond and a thioether bond. More specifically, the mesogen group includes those shown below, but the mesogen group is not limited thereto. The mesogen group They may be used alone or in combination from the examples of the structure of the mesogen group. Further, each skeleton may be provided with a substituent such as a cyano group, a halogen group, a methoxy group, a trifluoromethyl group or a methyl group. Both ends of these mesogen groups are selected from carboxyl groups, oxy groups and the like depending on the combination with the flexible chain. The flexible terminal chain and the flexible spacer chain are as follows.
Two or more kinds may be used in combination. Further, the present invention is not limited to this example. Flexible end chain _{-C m H 2m + 1 (m} = 1~18 integer) and _{CH 2 CH 2 O m CH 3} (m = 1~5 integer) spacer flexible chain CH _{2 l} (integer l = 0 to 18), CH ₂ CH ₂ O ₁ (l = 1 to 12 integer), CH ₂ CH ₂ CH ₂ O ₁ (1 = 1 to 10 integer), CH ₂ CH ₂ CH ₂ CH ₂ O ₁ (1 = 1 to 10) Integer), The liquid crystalline compound intermediate of the present invention is synthesized by binding the terminal flexible chain to the mesogen group and further binding the spacer flexible chain. At this time, the spacer flexible chain is required to have an unreacted unsaturated bond at the terminal, and by contracting this unsaturated bond and the siloxane compound with chloroplatinic acid, the liquid crystalline compound of the present invention can be obtained. can get. Specifically, a liquid crystal compound as shown in Table 1,
It is not limited to this. The liquid crystal compound of the present invention is excellent in high-speed response because it has a mesogen group bonded with a dimethylsiloxane group. If the dimethylsiloxane unit is long, the high-speed response is further improved, but if it is too long, the liquid crystal temperature region is reduced because the liquid crystallinity is impaired. Therefore, in the general formula (I), n is preferably 1-10. Further, n is preferably 1 to 5 in order to further increase the SmC ^* phase and obtain a high-speed response as a liquid crystal composition. The temperature range of the SmC ^* phase can be easily expanded by adding the liquid crystal compound of the present invention to another liquid crystal compound or liquid crystal composition. Moreover, the obtained liquid crystal composition of the present invention has good characteristics without a decrease in response speed. The following are examples of liquid crystal compounds suitable for the composition of the present invention. Examples of other liquid crystal compounds P-decyloxybenzylidene-P'-amino-2-methylbutyl cinnamate (DOBAMBC) P-hexyloxybenzylidene-P'-amino-2-chloropropyl lucinnamate (HOBACPC) P-decyloxybenzylidene-P'-amino-2-methylbutyl-α-cyanocinnamate (DOBAMBCC) P-tetradecyloxybenzylidene-P'-amino-2
-Methylbutyl-α-cyanocinnamate (TDOBAMBC
C) P-octyloxybenzylidene-P'-amino-2-
Methylbutyl-α-chlorocinnamate (OOBAMBCC) P-octyloxybenzylidene-P'-amino-2-
Methylbutyl-α-methylcinnamate 4,4'-azoxycinnamic acid-bis (2-methylbutyl) ester 4-o- (2-methyl) -butylresorcylidene-4 '
-Octylaniline (MBRA8) 4- (2'-methylbutyl) phenyl-4'-octyloxybiphenyl-4-carboxylate 4-hexyloxyphenyl-4- (2 "-methylbutyl) biphenyl-4'-carboxylate 4-octyloxyphenyl-4- (2 "-methylbutyl) biphenyl-4'-carboxylate 4'-heptylphenyl-4- (2 "-methylhexyl) biphenyl-4'-carboxylate 4- (2 "-methylbutyl) phenyl-4- (4" -methylhexyl) biphenyl-4'-carboxylate (SmA: Smectic A phase, Ch: Cholesteric phase The above numbers indicate ° C) For the liquid crystal composition, the liquid crystalline compound of the present invention is 1 to 90.
It is preferable to contain wt%. Further, when the liquid crystalline compound of the present invention has an optically active group, by adding it to the non-optically active liquid crystalline compound and containing it, the temperature range of the SmC ^* phase can be expanded and the response speed can be improved. It will be possible. Examples of the non-optically active liquid crystal compound that can be used in this manner are as follows. It is more preferable that these liquid crystalline compounds have an SmC ^* phase in terms of liquid crystal temperature range. It is not limited to this. Examples of liquid crystal compounds showing non-chiral smectic 4′-n-nonyloxy-4-biphenylyl-4-cyanobenzoate isotropic phase → nematic → smectic C 4-n-heptylphenyl-4- (4′-nitrobenzoyloxybenzoate) DB ₇ NO ₂ ) isotropic phase → nematic → smectic A 4-n-octylphenyl-4- (4′-nitrobenzoyloxy) benzoate (DB ₈ NO ₂ ) isotropic phase → nematic → smectic A → smectic C 4-n-decylphenyl-4- (4′-nitrobenzoyloxy) benzoate (DB ₁₀ NO ₂ ) isotropic phase → nematic → smectic A → smectic C Trans-4- (4 ″ -octyloxybenzoyloxy) -4′-cyanostilbene (T8) isotropic phase → nematic → smectic A ₁ → nematic → smectic A ₂ 4-n-Ventylphenyl-4- (4'-cyanobenzoyloxy) benzoate (DB ₅ CN) isotropic phase->nematic-> smectic A 4-n-nonyloxyphenyl-4- (4′-nitrobenzoyloxy) benzoate) (DB ₉ ONO ₂ ) isotropic phase → nematic → smectic A → smectic C 2- (4'-n-pentylphenyl) -5- (4 "-n
-Pentyloxyphenyl) pyrimidine isotropic phase → smectic A → smectic C → smectic F → smectic G Terephthalylidene-bis-4-n-pentylaniline (TBPA) isotropic phase → nematic → smectic A → smectic C → smectic F → smectic G → smectic H N-terephthalylidene-bis-4-n-butylaniline (TBBA) isotropic phase → nematic → smectic A → smectic C → smectic G → smectic H 4-Cyano-4'-n-octyloxybiphenyl (8O
CB) Isotropic phase → Nematic → Smectic A Ethyl-4-azobenzoate isotropic phase → smectic A N- (4'-n-butyloxybenzylidene) -4-n
-Octylaniline (4O.8) isotropic phase → smectic A → smectic B 4-n-hexyl-4′-n-hexyloxybiphenyl isotropic phase → smectic B → smectic E 4-n-hexyloxyphenyl-4′-n-octyloxybiphenyl-4-carboxylate isotropic phase → nematic → smectic A → smectic C → smectic B n-hexyl-4'-n-pentyloxybiphenyl-
4-carboxylate (65OBC) isotropic phase → smectic A → smectic B → smectic E 4-n-hexyl-4′-n-decyloxybiphenyl-4-carboxylate isotropic phase → smectic A → smectic C 4-n-heptyloxyphenyl-4-n-decyloxybenzoate isotropic phase → smectic A → smectic C 4-n-octyloxybenzoic acid isotropic phase → nematic → smectic C [Detailed Description of the Invention] The liquid crystal compound of the present invention is a reaction between a liquid crystal compound having an unsaturated bond group at the terminal and siloxanes. It can be synthesized by A method for producing the highly aligned liquid crystal compound represented by the above general formula (I) according to the present invention will be described. [Example 1] (+)-1,1,3,3 by the following steps (1) to (5)
-Tetramethyl-1,3-di-4 '-[4 "-(2-fluorooctyloxy) -phenyloxycarbonyl]
Phenyloxyundecanyl disiloxane was synthesized. (1) Synthesis of 10-undecenyl-p-toluenesulfonic acid ester 4.32 g (54.0 mM) of dry pyridine was added to 3.40 g (20.0 mM) of 10-undecen-1-ol, and the mixture was stirred at 0 ° C for 10 minutes. 3.80 g of p-toluenesulfonic acid chloride was added to this solution.
(20.0 mM) was added, and then the mixture was stirred at room temperature for 4 hours. After the reaction was completed, 2M hydrochloric acid was added to acidify the reaction solution, which was extracted with ether. Anhydrous sodium sulfate was added to this extract and dried, and then the ether was distilled off to obtain 6.20 g (19.1 mM) of 10-undecenyl-p-toluenesulfonic acid ester. Yield 9
5.5% (2) Synthesis of p- (10-undecenyl) oxybenzoic acid ethyl ester 10-undecenyl-p-toluenesulfonic acid ester
6 ml of dimethylformamide was added to 6.20 g (19.1 mM) and 3.17 g (19.1 mM) of p-hydroxybenzoic acid ethyl ester, and the mixture was stirred well. Add 60% sodium hydride to this solution.
77 g (19.3 mM) was added, and the mixture was heated under reflux for 7 hours. After the reaction was completed, dimethylformamide was distilled off, water was added, and the mixture was extracted with ether. Anhydrous sodium sulfate was added to this ether extract and dried, then the ether was distilled off, and the residue was separated and purified by column chromatography (developing solvent: methylene chloride).
There were obtained 5.80 g (18.2 mM) of p- (10-undecenyl) oxybenzoic acid ethyl ester. Yield 91.2% (3) Synthesis of p- (10-undecenyl) oxybenzoic acid p- (10-Undecenyl) oxybenzoic acid ethyl ester 5.80 g (18.2 mM) and sodium hydroxide 2.18 g (54.6
mM) dissolved in 4 ml of water and 30 ml of methanol were heated and stirred at 50 ° C. for 3 hours. After completion of the reaction, 20 ml of distilled water was added, methanol was distilled off, and the solution was acidified with 6M hydrochloric acid.
The p- (10-undecenyl) oxybenzoic acid thus produced was filtered and dried under reduced pressure in a desiccator. Thus 5.25 g of p- (10-undecenyl) oxybenzoic acid (18.
1 mM) was obtained. Yield 99.5% (4) Synthesis of (-)-p- (10-undecenyl) oxybenzoic acid-p '-(2-fluorooctyloxy) phenyl ester p- (10-Undecenyl) oxybenzoic acid 1.13 g ( 3.9
(mM) was heated under reflux with 8 ml of thionyl chloride for 3 hours, and then unreacted thionyl chloride was distilled off to obtain an acid chloride. Next, a solution of 0.87 g (7.80 mM) of triethylenediamine in 5 ml of dry benzene was added to (+)-p- (2-fluorooctyloxy) phenol ([α] _D ²⁷ + 3.92 ° (c
2, CH ₂ Cl ₂ )) 0.94 g (3.9 mM) was added to the above acid chloride with stirring. After completion of dropping, the mixture was heated at 50 ° C for 2 hours. To this was added 0.19 g (4.70 mM) of 60% sodium hydride together with dry benzene, and the mixture was heated under reflux for 2 hours. After the reaction was completed, the solution was acidified with 2M hydrochloric acid and extracted with benzene. Anhydrous sodium sulfate was added to this extract to dry it, then benzene was distilled off, the residue was separated and purified by column chromatography (developing solvent: benzene), and recrystallized with 4 ml of hexane to obtain (-)-p- (10- 1.35 g (2.64 mM) of undecenyl) oxybenzoic acid-p '-(2-fluorooctyloxy) phenyl ester was obtained. Yield 67.6%, [α] _D ²⁷ −
3.40 ° (c1, benzene) (5) (+)-1,1,3,3-tetramethyl-1,3-di-4 '
Synthesis of-[4 "-(2-fluorooctyloxy) -phenyloxycarbonyl] phenyloxyundecanyl-disiloxane (-)-p- (10-undecenyl) oxybenzoic acid-
Mix 0.26 g (0.5 mM) of p '-(2-fluorooctyloxy) phenyl ester and 0.5 ml of dry toluene and add 3 m of isochlorochloroplatinate isopropanol solution (1M solution) with stirring.
g (approximately 0.002 mM) was added. Stir for about 3 minutes, then 1,1,
3,3-Tetramethyldisiloxane (0.067 g, 0.5 mM) was added, and the mixture was heated at 100 ° C for 7 hours. Furthermore, (-)-p- (10
-Undecenyl) oxybenzoic acid-p '-(2-fluorooctyloxy) phenyl ester 0.080 g (0.16 mM)
Was added and heated at 100 ° C. for 4 hours. After the reaction was completed, the product was separated and purified by column chromatography (developing solvent: methylene chloride: hexane = 1: 1) and recrystallized with 5 ml of hexane to obtain (+)-1,1,3,3-tetramethyl- 0.272 g (0.23 mM) of 1,3-di-4 '-[4 "-(2-fluorooctyloxy) -phenyloxycarbonyl] phenyloxyundecanyl disiloxane was obtained.
Yield 70.7%, [α] _D ²⁸ + 1.40 ° (c0.86, CH ₂ Cl ₂ ) [Example 2] (+)-1,1,3,3-tetramethyl-1,3-di-4 '-[4 "-(2-fluorooctyloxy) -phenyl synthesized in Example 1 [Oxycarbonyl] phenyloxyundecanyl disiloxane was enclosed in a 17 μm-thick PI rubbing cell and the response speed was measured at 70 ° C.
It was ec (8V / μm). [Example 3] (+)-1,1,3,3-tetramethyl-1,3-di-4'-
[4 ″-(2-Fluorooctyloxy) -phenyloxycarbonyl] phenyloxyundecanyl disiloxane to 1 part by weight of (+)-4-decyloxybenzoic acid-4 ′-(2 ″ -fluoro When 9 parts by weight of octyloxy) -phenyl ester was obtained, SmC was measured at 83-58 ° C.
^* Indicates a phase. [Example 4] (+)-1,1,3,3 by the following steps (1) to (3)
-Tetramethyl-1,3-di-4- [4 "-(2-fluorooctyloxy) -phenylcarbonyloxy] phenyloxyundecanyl disiloxane was synthesized. (1) Synthesis of p- (10-undecenyl) oxyphenol 10-undecenyl-p-toluenesulfonic acid ester
3 ml of butanol was added to 2.60 g (8.02 mM) and 1.79 g (16.2 mM) of hydroquinone, and the mixture was further stirred. A solution prepared by dissolving 0.41 g (9.74 mM) of sodium mercuride in 6 ml of butanol was added to the solution, and the mixture was heated under reflux at 110 ° C for 7 hours. After the reaction was completed, butanol was distilled off, water was added, and the mixture was extracted with ether. Anhydrous sodium sulfate was added to this extract solution for drying, the ether was distilled off, and the residue was separated and purified by column chromatography (developing solvent: methylene chloride).
p- (10-undecenyl) oxyphenol 1.00 g (3.8
2mM) was obtained. Yield 47.6% (2) Synthesis of (-)-p- (2-fluorooctyloxy) benzoic acid-p '-(10-undecenyloxy) phenyl ester (+)-p- (2-fluorooctyl) (Oxy) benzoic acid 0.54 g (2.0 mM) with thionyl chloride 3 ml for 1 hour 30
After heating under reflux for a minute, unreacted thionyl chloride was distilled off to obtain an acid chloride. Next, 0.52 g (2.0 mM) of p- (10-undecenyloxy) phenol was added to a solution prepared by dissolving 0.45 g (4.0 mM) of triethylenediamine in 3 ml of dry benzene, and added dropwise with stirring in the above acid chloride. did. After completion of dropping, the mixture was heated at 50 ° C for 2 hours. To this, 0.08 g (2.0 mM) of 60% sodium hydride was added together with dry benzene, and the mixture was heated under reflux for 2 hours. After the reaction was completed, the solution was acidified with 2M hydrochloric acid and extracted with benzene. Anhydrous sodium sulfate was added to this extract and dried, then benzene was distilled off, separated and purified by column chromatography (developing solvent: benzene), and further 2 ml of hexane.
Recrystallization from (-)-p- (2-fluorooctyloxy) benzoic acid-p '-(10-undecenyloxy) phenyl ester gave 0.65 g (1.27 mM). Yield 63.5%.
[Α] _D ²⁶ −4.27 ° (c1.03, benzene). (3) (+)-1,1,3,3-tetramethyl-1,3-di-4 '
Synthesis of-[4 "-(2-fluorooctyloxy) -phenylcarbonyloxy] phenyloxyundecanyl-disiloxane (-)-p- (2-fluorooctyloxy) benzoic acid-p '-(10 -Undecenyloxy) phenyl ester
Mix 0.256 g (0.5 mM) and 0.5 ml of dry toluene, and stir 3 mg of isochlorochloroplatinate isopropanol solution (1M solution).
(About 0.002 mM) was added. Stir for about 3 minutes, then 1,1,
Add 3,67-tetramethyldisiloxane 0.067g (0.5mM)
Heated at 100 ° C. for 7 hours. Further, 0.080 g (0.16 mM) of (−)-p- (2-fluorooctyloxy) benzoic acid-p ′-(10-undecenyloxy) phenyl ester was added, and the mixture was heated at 100 ° C. for 4 hours. After the reaction was completed, the product was separated and purified by column chromatography (developing solvent: methylene chloride: hexane = 1: 1) and recrystallized with 3 ml of hexane to obtain (+)-1,1,3,3-
Tetramethyl-1,3-di-4 '-[4 "-(2-fluorooctyloxy) -phenylcarbonyloxy] phenyloxyundecanyl disiloxane 0.230 g (0.2 m
M). Yield 60.2% [α] _D ²⁶ + 2.21 ° (c1, CH ₂ C
l ₂ ). [Example 5] 1,1,3,3-tetramethyl-1,3-di-4- [4 "-(3-trifluoromethylheptyloxy)-by the following steps (1) and (2) Phenyloxycarbonyl] phenyloxyundecanyl disiloxane was synthesized. (1) p- (10-undecenyl) oxybenzoic acid-p '
Synthesis of-(3-trifluoromethylheptyloxy) phenyl ester p- (10-undecenyl) oxybenzoic acid 0.44 g (1.5
(mM) was heated under reflux with 2 ml of thionyl chloride for 2 hours, and then unreacted thionyl chloride was distilled off to obtain an acid chloride. On the other hand, a solution of 0.34 g (3.0 mM) of triethylenediamine in 3 ml of dry benzene was added to 0.41 g (1.5 mM) of p- (3-trifluoromethylheptyloxy) phenol, and the mixture was stirred while cooling with ice. The benzene solution of acid chloride prepared above was added dropwise to this solution. 50 ℃ after dropping
After stirring at room temperature for 2 hours, add 60% sodium hydride 40mg to it.
Was added with dry benzene, and the mixture was heated under reflux for 2 hours. After the reaction was completed, the solution was acidified with 2M hydrochloric acid and extracted with ether. Anhydrous sodium sulfate was added to this extract and dried, the solvent was distilled off, and the residue was separated and purified by column chromatography (developing solvent: benzene) and p- (10-undecenyl) oxybenzoic acid-p '-( 0.38 g (0.7 m of 3-trifluoromethylheptyloxy) phenyl ester
M). 46% yield. (2) 1,1,3,3-tetramethyl-1,3-di-4 '[4 "-
Synthesis of 3-trifluoromethylheptyloxy) -phenyloxycarbonyl] phenyloxyundecanyldisiloxane p- (10-undecenyl) oxybenzoic acid-p'-
(3-trifluoromethylheptyloxy) phenyl ester 0.100 g (0.18 mM) and dry toluene 0.2 ml are mixed,
With stirring, 3 mg (about 0.002 mM) of isopropanolic chloroplatinate solution (1M solution) was added. After stirring for about 3 minutes, 0.024 g of 1,1,3,3-tetramethyldisiloxane (0.18 m
M) was added and heated at 100 ° C. for 7 hours. Furthermore, p- (10-undecenyl) oxybenzoic acid-p '-(3-trifluoromethylheptyloxy) phenyl ester 0.020 g (0.
036 mM) was added and the mixture was heated at 100 ° C. for 5 hours. After completion of the reaction, the product was separated and purified by column coromatography (developing solvent: methylene chloride: hexane = 1: 1), and 1,1,3,3-tetramethyl-1,3-di-4 '-[ 4 ″-
0.080 g (0.065 mM) of (3-trifluoromethylheptyloxy) -phenyloxycarbonyl] phenyloxyundecanyl disiloxane was obtained. 72.3% yield. [Effects of the Invention] As described above, the liquid crystal compound and composition of the present invention have SmC ^{* in a} wide temperature range and are excellent in high-speed response.

Claims (1)

(57) [Claims] A liquid crystal compound represented by the following general formula (I). General formula (I) (In the formula, R ₁ and R ₂ represent a liquid crystal residue BY _P AX _Q C-, and at least one of R ₁ and R ₂ has an optically active group. N is an integer of 1 to 10. In the above liquid crystalline residue BY _P AX _Q C-, A is a mesogen group selected from the group consisting of the following groups, B is a flexible terminal chain selected from the group consisting of -C _m H _{2m + 1} (m = 1 to 18 integer) and CH ₂ CH ₂ O _m CH ₃ (m = 1 to 5 integer) C is a spacer flexible chain selected from the group consisting of the following chains. , CH _{2 l} (l = 0 to 18 integer), CH ₂ CH ₂ O _l (l = 1 to 12 integer), CH ₂ CH ₂ CH ₂ O _l (l = 1 to 10 integer), CH ₂ CH ₂ CH ₂ CH ₂ O ₁ (l = 1 integer of 1) and P and Q are both 1, and X and Y are bonds selected from the group consisting of ester bonds, ether bonds, thioester bonds, thioester bonds, and thioether bonds. ) 2. The liquid crystal compound according to claim 1, which is a compound exhibiting a smectic phase. 3. The liquid crystal compound according to claim 1, which is a compound exhibiting a chiral smectic phase. 4. A method for producing a liquid crystal compound, which comprises reacting a liquid crystal compound having an unsaturated bond group at a terminal with a siloxane chain to obtain a liquid crystal compound represented by the following general formula (I). General formula (I) (In the formula, R ₁ and R ₂ represent a liquid crystal residue BY _P AX _Q C-, and at least one of R ₁ and R ₂ has an optically active group. N is an integer of 1 to 10. In the above liquid crystalline residue BY _P AX _Q C-, A is a mesogen group selected from the group consisting of the following groups, B is a flexible terminal chain selected from the group consisting of -C _m H _{2m + 1} (m = 1 to 18 integer) and CH ₂ CH ₂ O _m CH ₃ (m = 1 to 5 integer) C is a spacer flexible chain selected from the group consisting of the following chains. , CH _{2 l} (l = 0 to 18 integer), CH ₂ CH ₂ O _l (l = 1 to 12 integer), CH ₂ CH ₂ CH ₂ O _l (l = 1 to 10 integer), CH ₂ CH ₂ CH ₂ CH ₂ O ₁ (l = 1 integer of 1) and P and Q are both 1, and X and Y are bonds selected from the group consisting of ester bonds, ether bonds, thioester bonds, thioester bonds, and thioether bonds. ) 5. A liquid crystal composition containing at least one liquid crystal compound represented by the following general formula. General formula (I) (In the formula, R ₁ and R ₂ represent a liquid crystal residue BY _P AX _Q C-, and at least one of R ₁ and R ₂ has an optically active group. N is an integer of 1 to 10. In the above liquid crystalline residue BY _P AX _Q C-, A is a mesogen group selected from the group consisting of the following groups, B is a flexible terminal chain selected from the group consisting of -C _m H _{2m + 1} (m = 1 to 18 integer) and CH ₂ CH ₂ O _m CH ₃ (m = 1 to 5 integer) The above C is a spacer flexible chain selected from the group consisting of the following chains. Yes, CH _{2 l} (l = 0 to 18 integer), CH ₂ CH ₂ O ₁ (l = 1 to 12 integer), CH ₂ CH ₂ CH ₂ O ₁ (l = 1 to 10 integer), CH ₂ CH ₂ CH ₂ CH ₂ O ₁ (l = 1 to an integer of 1 to 10) and Both P and Q are 1, and X and Y are bonds selected from the group consisting of ester bonds, ether bonds, thioester bonds, thioester bonds, and thioether bonds. ) 6. The liquid crystal composition according to claim 5, wherein the liquid crystal compound is a compound exhibiting a smectic phase. 7. The liquid crystal composition according to claim 5, wherein the liquid crystal compound is a compound exhibiting a chiral smectic phase. 8. 6. A liquid crystal compound containing the liquid crystal compound and a liquid crystal compound different from the compound and exhibiting a smectic phase.
Item. 9. The liquid crystal composition according to claim 5, which contains the liquid crystal compound and a liquid crystal compound which is different from the compound and exhibits a chiral smectic phase. 10. The liquid crystal composition according to claim 5, which is a composition exhibiting a chiral smectic phase.