JPH0553780B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a novel liquid crystal substance and a liquid crystal composition containing the liquid crystal substance, and more particularly to a chiral liquid crystal substance having an optically active group and a chiral liquid crystal composition containing the same. [Background of the invention] Currently, TN (Twisted
Nematic type display devices are the most widely used, but they are inferior to light emitting type display devices (electroluminescent displays, plasma displays, etc.) in terms of response speed, and improvements in this point are not possible. Although various attempts have been made to no avail, there does not seem to be much potential for significant improvement. Therefore
Various attempts have been made to develop liquid crystal display devices based on different principles to replace TN-type element displays, one of which is a display method that uses ferroelectric liquid crystals (NAClark
et al.; Applied Phys.lett., 36, 899 (1980)). This method utilizes the chiral smectic C phase (hereinafter referred to as SC ^* phase) or chiral smectic H phase (hereinafter referred to as SH ^* phase) of ferroelectric liquid crystal. It is desirable that the temperature be around room temperature. [Objective of the Invention] The present inventors have been searching for various liquid crystal materials having optically active groups, with the main purpose of developing liquid crystal materials suitable for use in this display method. The present invention has been achieved. [Structure of the invention] That is, the present invention is based on the general formula (However, in formula (), R ₁ represents an alkyl group having 1 to 18 carbon atoms, R ₂ represents an alkyl group having 2 to 15 carbon atoms, and X is a single bond -O-, or

A compound represented by the following formula (where * represents an optically active carbon atom) and a liquid crystal composition containing the same. When the compounds of formula () of the present invention are divided by X in formula (), they become compounds represented by the following six formulas. That is, optically active 4'-alkyl-4-biphenylcarboxylic acid 4-(1-methylalkyloxy)phenyl esters, That is, optically active 4'-alkyloxy-4-biphenylcarboxylic acid 4-(1-methylalkoxy)
phenyl esters, That is, optically active 4'-alkyloxycarbonyloxy-4-biphenylcarboxylic acid 4-(1-methylalkyloxy)phenyl esters,
(Both R ₁ and R ₂ are the same as above.) Table 1 also shows the phase transition temperatures of typical compounds of formula ().

〔Effect of the invention〕

Most of the compounds of formula () are isotropic liquids (
Smekchitsk A phase (hereinafter referred to as A phase) in a lower temperature range than
(abbreviated as SA phase), and in the lower temperature range
Many exhibit SC ^* . Furthermore, the present inventors have discovered that the value of spontaneous polarization in the SC ^* phase is several orders of magnitude larger than that of conventionally known compounds. Table 2 shows the magnitude of spontaneous polarization of representative compounds among the compounds of formula () of the present application and the magnitude of spontaneous polarization of conventionally known chiral smectic compounds. Note that the magnitude of spontaneous polarization is a value measured at a temperature 20° C. lower than the SC ^* -SA phase transition temperature.

[Production method of compound]

Next, a method for producing the compound of general formula () will be described. The compound of formula () can be synthesized by the route shown below. (In the above formula, Hal represents a halogen atom.Others are the same as above.) That is, one of the raw materials, 4'-substituted-4-biphenylcarboxylic acid halide (), and the other raw material, optically active p- It can be produced by reacting (1-methylalkyloxy)phenols () in a basic solvent such as pyridine. More specifically, one of the raw materials, 4'-substituted-4
-The following compounds are used as the biphenylcarboxylic acid halide (). All of the above compounds are known, and for example, (f) 4'-alkyloxycarbonyloxy-4-biphenylcarboxylic acid halide is produced by the following steps. That is, when 4'-hydroxy-4-formylbiphenyl (2) is reacted with a commercially available alkyl chloroformate in pyridine, 4'-alkyloxycarbonyloxy-4-formylbiphenyl (5) is produced. (Five)
When an oxidizing agent such as chromium trioxide is applied to
Alkyloxycarbonyloxy-4-biphenylcarboxylic acid (6) is produced. When (6) is reacted with a halogenating agent such as thionyl chloride, 4'-alkyloxycarbonyloxy-4-biphenylcarboxylic acid halide (f) is obtained. Moreover, the other raw material, p-(1-methylalkyloxy)phenols (), can be produced by the following steps. That is, optically active 1-methyl-1-alkanol
Optically active p-toluenesulfonic acid (1-methylalkyl) ester (8) is produced by reacting (7) with commercially available p-toluenesulfonic acid chloride in pyridine. Optically active p-benzyloxy-(1
-Methyloxy)benzene (9) is produced. this
When (9) is subjected to a hydrogenolysis reaction using hydrogen using palladium-carbon as a catalyst, optically active p-(1-methylalkoxy)phenols () are produced. Raw material () and raw material (a), (b), or (
By reacting with f), a compound of formula (a), (b) or (f) described above can be obtained, respectively. [Example] The optically active liquid crystal compound and liquid crystal composition of the present invention will be explained in more detail with reference to Examples below. Example 1 [Optically active 4'-octyloxy-4-biphenylcarboxylic acid 4-(1-methylheptyloxy)]
Phenyl ester (in the formula (), R ₁ is
C ₈ H ₁₇ , R ₂ is C ₆ H ₁₃ , X is -O-, the first
Production of compound No. 9 in the table] 200 g (1.536 mol) of S-(+)-2-octanol was dissolved in 600 ml of dry pyridine, and while making sure that the temperature in the system did not rise above 10°C, p-toluene was added. A solution of 292.8 g (15.36 mol) of sulfonic acid chloride in 440 ml of dry toluene is added dropwise.
After the dropwise addition was completed, the mixture was stirred at room temperature for 1 hour, and then the temperature inside the system was raised to 50°C, maintained for 2 hours, and then cooled. After adding 1 water and 500 ml of toluene and stirring,
The toluene layer is washed with 6N hydrochloric acid, then with 2N sodium hydroxide solution, and then with water until neutral. When toluene is distilled off, the residue is 321.0
Optically active p-toluenesulfonic acid 1-methylheptyl ester (8) of g was obtained. Meanwhile, 50g of commercially available p-benzyloxyphenol
(0.266 mol), 150 ml of ethanol, and 25 g of 50% aqueous sodium hydroxide solution were mixed and stirred, and 83 g (0.292 mol) of the above optically active p-toluenesulfonic acid 1-methylheptyl ester was poured into the mixture, and the mixture was stirred for 4 hours. The mixture was heated and stirred at 70°C. Then, after distilling off most of the ethanol, add 200ml of toluene and 6N hydrochloric acid.
300 ml was added, shaken, and filtered to remove the insoluble portion. Wash twice with 300 ml of 6N hydrochloric acid to remove insoluble parts, and then wash with saturated saline and then with 2N-
After washing three times with 200 ml of sodium hydroxide aqueous solution, it was washed again with saturated saline until neutral. After drying and concentration, it was purified using 150 g of activated alumina and concentrated to obtain 68.6 g (oil) of p-benzyloxy-(1-methylheptyloxy)benzene (9). Since this product is thought to undergo Walden inversion during the reaction, it is presumed to be the R-form. This product was subjected to a hydrogenolysis reaction in ethanol using a 5% palladium-carbon catalyst, and after the reaction, the catalyst was removed and concentrated. This is distilled under reduced pressure to produce bp129-130.5℃/0.5Torr.
30.7 g (oil) of p-(1-methylheptyloxy)phenol () was obtained. Dissolve 1.5 g of this product in 5 ml of pyridine and add 4'-octyloxy-4-biphenylcarboxylic acid chloride.
A solution of 2.0 g in 5 ml of dry toluene was injected under ice cooling, heated on a 60°C water bath for 2 hours, and then left overnight. Add 50 ml of toluene and 100 ml of 6N hydrochloric acid, shake, filter to remove insoluble parts, wash with 6N hydrochloric acid, saturated saline, and 2N sodium hydroxide aqueous solution, and then wash with saturated saline to neutralize. did. After drying and concentrating it, it was concentrated using column chromatography using 15 g of activated alumina and toluene as an eluent, and then recrystallized with a mixture of 25 ml of ethanol and 15 ml of ethyl acetate to obtain the final target product, 4'-octyl. 1.7 g of oxy-4-biphenylcarboxylic acid 4-(1-methylheptyl)phenyl ester () was obtained. The phase transition point of this product is C-SX point 65.7℃, SX
-SC ^* point 84.3℃, SC ^* -SA point 107.2℃, SA-I point
The temperature was 151.8℃. Moreover, the elemental analysis values of this compound were in good agreement with the calculated values as shown below. Actual value Actual value (as C ₃₅ H ₄₆ O ₄ ) C 79.4% 79.20% H 8.5% 8.74% Instead of the above 4'-octyloxy-4-biphenylcarboxylic acid chloride, other 4'-substituted-4 - Optically active 4'-substituted-4-biphenylcarboxylic acid 4-(1-methylheptyl)phenyl esters corresponding to No. 5 to No. 13 in Table 1 were obtained using biphenylcarboxylic acid halide. Ta. Their phase transition temperatures are shown in Table 1 along with the results for No. 9. Example 2 [Optically active 4'-octyl-4-biphenylcarboxylic acid 4-(1 methylbutyloxy)phenyl ester (in the formula (), R ₁ is C ₈ H ₁₇ and R ₂ is
Production of C ₃ H ₇ , X is a single bond, No. 1 compound in Table 1) 163.4 g (1.85 mol) of S-(+)-2-pentanol was dissolved in 740 ml of dry pyridine, and the system A solution prepared by dissolving 353 g (1.85 mol) of p-toluenesulfonic acid chloride in 524 ml of dry toluene was added dropwise while ensuring that the temperature inside the flask did not rise above 10°C. After the dropwise addition was completed, the mixture was stirred at room temperature for 1 hour, and then the temperature inside the system was raised to 50°C, maintained for 2 hours, and then cooled. 1 portion of water and 500 ml of toluene were added and stirred.
The toluene layer was washed with 6N hydrochloric acid, then with 2N aqueous sodium hydroxide solution, and further washed with water until neutral. When toluene was distilled off, 413.9 g of optically active p-toluenesulfonic acid 1-methylbutyl ester (8) was obtained. Next, commercially available p-benzyloxyphenol 50
g (0.266 mol), 150 ml of ethanol, and 25 g of 50% aqueous sodium hydroxide solution were mixed and stirred, and 70 g (0.289 mol) of the above optically active p-toluenesulfonic acid 1-methylbutyl ester was poured into the mixture and stirred for 4 hours. The mixture was heated and stirred at ℃. After that, most of the ethanol was distilled off, and 200 ml of toluene and 300 ml of 6N hydrochloric acid were added.
ml was added, shaken, and filtered to remove the insoluble portion.
Washed twice with 300 ml of 6N hydrochloric acid, filtered to remove insoluble parts, washed with saturated brine, then three times with 200 ml of 2N sodium hydroxide solution, and washed again with saturated brine until neutral. . After drying and concentration, it was purified using 200 g of activated alumina and concentrated to obtain 58.3 g (oil) of p-benzyloxy-(1-methylbutyloxy)benzene. The steric configuration is presumed to be R as in Example 1. This product was subjected to a hydrogenolysis reaction in ethanol using a 5% palladium-carbon catalyst, and after the reaction, the catalyst was removed and concentrated. Distill this under reduced pressure and b.
21.9 g (oil) of p-(1-methylbutyloxy)phenol () having a temperature of 110 to 110.5° C./2 Torr was obtained. 0.5 g of this product was dissolved in 5 ml of pyridine, and 0.8 g of 4'-octyl-4-biphenylcarboxylic acid chloride dissolved in 5 ml of dry toluene was poured into the solution under ice cooling. After heating for 2 hours, it was left overnight. Add 50 ml of toluene and 100 ml of 6N hydrochloric acid to this, separate the layers, and separate the organic layer from 6N hydrochloric acid, saturated saline,
After washing with 2N-sodium hydroxide aqueous solution,
Furthermore, it was washed with saturated saline to make it neutral. After drying and concentrating it, it was heated with activated carbon using 20ml of ethanol, and the crystals formed by cooling were collected.
It was dissolved again in a mixed solvent of 20 ml of ethanol and 10 ml of ethyl acetate, heated, cooled, and recrystallized. The crystals were collected to obtain 0.30 g of 4'-octyl-4-biphenylcarboxylic acid 4-(1-methylbutyl)phenyl ester (). The phase transition point of this product was 56.1°C at the C-SA point and 127.5°C at the SA-I point. Moreover, the elemental analysis values of this compound were in good agreement with the calculated values as shown below. Actual value Actual value (as C ₃₂ H ₄₀ O ₃ ) C 81.2% 81.31% H 8.7% 8.53% Instead of the above 4'-octyl-4-biphenylcarboxylic acid chloride, other 4'-substituted-4
- Using biphenylcarboxylic acid halide, the first
Optically active 4′-substituted-4 corresponding to No. 2 to No. 4 in the table
-Biphenylcarboxylic acid 4-(1-methylbutyloxy)phenyl esters were obtained. Their phase transition temperatures are also shown in Table 1. Example 3 [4'-nonyloxycarbonyloxy-4-biphenylcarboxylic acid 4-(1-methylnonyloxy)phenyl ester (R ₁ in the formula ())
is C ₉ H ₁₉ , R ₂ is C ₈ H ₁₇ , and X is

Production of [formula], compound No. 18 in Table 1] S-(+)-2-decanol 61.9 g (0.39 mol)
was dissolved in 280 ml of dry pyridine, and the temperature in the system was 10
A solution of 74.6 g (0.39 mol) of p-toluenesulfonic acid chloride dissolved in dry toluene was added dropwise while keeping the temperature from exceeding .degree. After the dripping is finished,
After stirring at room temperature for 1 hour, the temperature inside the system was raised to 50°C, maintained for 2 hours, and then cooled. 1 portion of water and 500 ml of toluene were added and stirred. The toluene layer was washed with 6N hydrochloric acid, then with 2N aqueous sodium hydroxide solution, and further washed with water until neutral. When toluene was distilled off, 105.3 g of optically active p-toluenesulfonic acid 1-methylnonyl ester (8) was obtained. Next, 25g of commercially available p-benzyloxyphenol
(0.133 mol), 120 ml of ethanol, and 12.8 g of a 50% aqueous sodium hydroxide solution were mixed and stirred, and 43 g (0.138 mol) of the above optically active p-toluenesulfonic acid 1-methylnonyl ester was poured into the mixture, and the mixture was stirred for 4 hours. The mixture was heated and stirred at 70°C. After that, most of the ethanol was distilled off, and 200ml of toluene and 300ml of 6N hydrochloric acid were added.
was added, shaken, and filtered to remove insoluble parts.
The insoluble portion was removed by washing twice with 300 ml of 6N hydrochloric acid, and then washed three times with saturated brine, then with 200 ml of 2N aqueous sodium hydroxide solution, and then with saturated brine until neutral. After drying and concentrating,
Purification was performed using 100 g of activated alumina to obtain 44.1 g (oil) of p-benzyloxy-(1-methylnonyloxy)benzene. The steric configuration is Example 1,
Like 2, it is presumed to be R. This product was subjected to a hydrogenolysis reaction in ethanol using a 5% palladium-carbon catalyst, and then the catalyst was removed and concentrated. Distill this under reduced pressure to bp145-147
p-(1-methylnonyloxy) at °C/1.5Torr
12.7 g (oil) of phenol () was obtained. Dissolve 0.5 g of this product in 5 ml of pyridine and add 4'-nonyloxycarbonyloxy-
A solution of 0.7 g of 4-biphenylcarboxylic acid chloride in 5 ml of dry toluene was injected under ice cooling, heated on a 60°C water bath for 2 hours, and then left overnight. Add 50ml of toluene and 100ml of 6N hydrochloric acid to this, separate the organic layer, wash with 6N hydrochloric acid, wash with saturated saline,
The mixture was washed with a 2N aqueous sodium hydroxide solution and further washed with saturated saline to neutralize it. After drying and concentration, the mixture was heated with activated carbon using 20 ml of ethanol.
The crystals formed after cooling were collected, dissolved again in a mixed solvent of 20 ml of ethanol and 10 ml of ethyl acetate, heated, cooled, and recrystallized. The crystals were collected to obtain 0.46 g of the target product, 4'-nonyloxycarbonyloxy-4-biphenylcarboxylic acid 4-(1-methylnonyloxy)phenyl ester (). The phase transition point of this substance is C-SC ^* point 72.1℃,
The SC ^* -SA point was 118.8°C, and the SA-I point was 125.6°C. Moreover, the elemental analysis values of this compound were in good agreement with the calculated values as shown below. Actual value Actual value (as C ₃₉ H ₅₂ O ₆ ) C 75.8% 75.94% H 8.7% 8.50% In place of the above 4'-nonyloxycarbonyloxy-4-biphenylcarboxylic acid chloride, other 4'-substituted Using -4-biphenylcarboxylic acid halide, optically active 4'-substituted-4-biphenylcarboxylic acid 4 corresponding to No. 14 to No. 17 in Table 1 was prepared.
-(1-methylnonyloxy)phenyl esters were obtained. Their phase transition temperatures are also shown in Table 1. Example 4 (Use example 1) 4-ethyl-4'-cyanobiphenyl 20% (weight, same as below) 4-pentyl-4'-cyanobiphenyl 40% 4-octyloxy-4'-cyanobiphenyl 25% 4-pentyl-4 A nematic liquid crystal composition consisting of 15% of '-cyanoterphenyl was coated with polyvinyl alcohol (PVA) as an alignment agent.
Injected into transparent electrodes (electrode spacing of 10 μm) whose surfaces were rubbed and subjected to parallel alignment treatment.
When a TN display cell was observed under a polarizing microscope, it was observed that a reverse twist domain was generated. To the above nematic liquid crystal composition, 1% by weight of a compound (No. 1) of formula ( ) of the present application in which R ₁ is C ₈ H ₁₇ , X is a single crystal, and R ₂ is C ₃ H ₇ is used. hand,
When similarly observed in a TN cell, the reverse twist domain was resolved and a uniform nematic phase was observed. Example 5 (Use Example 2) All are compounds of the present invention. (No. 4) 35% (No.9) 35% (No.13) 20% (No. 14) A mixture consisting of 10%
It shows SC ^* phase, and at higher temperature it shows SA phase,
Becomes an isotropic liquid at 120℃. The magnitude of the spontaneous polarization of this mixture is
It exhibits a very large value of 50nC/cm ² and has a tail angle of 22°, which is optimal for a birefringent display element that uses a polarizing plate. PVA is applied to this mixture as an orientation treatment,
The liquid crystal cell was injected into a cell with an electrode spacing of 2 μm and equipped with transparent electrodes whose surfaces had been subjected to parallel alignment treatment by rubbing, and this liquid crystal cell was sandwiched between two polarizers arranged orthogonally to each other, and a low voltage of 0.5 Hz and 15 V was applied. When an alternating current frequency was applied, a clear switching operation with very good contrast was observed, and the response speed was 50%.
A very fast liquid crystal display element of 0.2 msec at ℃ was obtained. Example 6 (Use Example 3) All are compounds of the present invention. (No.10) (No.12) (No. 13) and two known chiral smectic compounds with small spontaneous polarization (about 1 nC/cm ² ) but large tail angle (45°). An equal mixture of five components with the addition of
It exhibits SC ^* phase up to 98℃, changes to Ch phase at higher temperatures, and becomes an isotropic liquid at 142℃. The tail angle of this mixture is as large as 35° at 50°C.
It is more suitable for guest-host type display elements that use dichroic dyes than birefringent type display elements, and
The magnitude of spontaneous polarization was extremely large at 38 nC/cm ² . To this mixture, 3% by weight of an anthraquinone dye D-16 (BDH product) was added as a dichroic dye to create a so-called guest-host type mixture, which was injected into a cell similar to that in Example 5. When applying a low frequency alternating current of 0.5 Hz and 15 V using a polarizing plate, a clear switching operation with very good contrast was observed, and the response speed was 0.5 msec at 50°C.
An extremely fast color liquid crystal display element was obtained. Example 7 (Use example 4) All are compounds of the present invention (No.9) (No.10) (No. 12) A mixture of equal amounts of three compounds is heated from 53℃ to 121℃
It shows SC ^* phase in the temperature range of , and above
It shows SA phase and becomes an isotropic liquid at 121℃. The magnitude of the spontaneous polarization of this mixture is
It has a very large temperature of 80nC/cm ² and a tail angle of 25°, making it suitable for birefringent display elements that use two polarizing plates. This mixture was injected into a cell similar to Example 5,
When operated under the same conditions, a liquid crystal display element with very good contrast and a very fast response time of 0.1 msec at 55°C was obtained.

Claims (1)

[Claims] 1. General formula (However, in formula (), R ₁ represents an alkyl group having 1 to 18 carbon atoms, R ₂ represents an alkyl group having 2 to 15 carbon atoms, and X is a single bond, -O- or -OCOO- (* indicates an optically active carbon atom)
A compound represented by 2 General formula (However, in formula (), R ₁ represents an alkyl group having 1 to 18 carbon atoms, R ₂ represents an alkyl group having 2 to 15 carbon atoms, and X is a single bond, -O- or -OCOO- (* indicates an optically active carbon atom)
A liquid crystal composition comprising two or more components, characterized by containing at least one compound represented by: 3. The chiral smectic liquid crystal composition according to claim 2, which comprises a plurality of compounds of formula (). 4. The chiral nematic liquid crystal composition according to claim 2, which contains a nematic liquid crystal substance as one component. 5 General formula (However, in formula (), R ₁ represents an alkyl group having 1 to 18 carbon atoms, R ₂ represents an alkyl group having 2 to 15 carbon atoms, and X is a single bond, -O- or -OCOO- (* indicates an optically active carbon atom)
An optical switching element constructed using a liquid crystal composition exhibiting a chiral smectic C phase, which is composed of two or more components containing at least one compound represented by the following.