JP4019327B2 - 2-fluorobiphenyl derivatives - Google Patents

Description

  The present invention relates to a novel 2-fluoro-4-alkyl-4'-ethynylbiphenyl that is a synthetic intermediate of a liquid crystal compound that is a novel 2-fluorobiphenyl derivative that is useful as an electro-optical display material.

  Liquid crystal display elements have recently been used as information display elements such as clocks and calculators, word processors, computer terminal displays, and the like, and have become increasingly important as an interface between electronic devices and people.

  Display systems using liquid crystals are roughly classified into three types: a field effect (FEM) type, a dynamic scattering (DSM) type, and a thermal effect (TEM) type. Various display systems have been proposed using these effects. Up to now, display systems using the field effect type have been put into practical use. The field effect types include twisted nematic (TN), super twisted nematic (STN), guest-host (GH), electric field controlled birefringence (ECB), and cholesteric-nematic phase transition (CN-PT). Type, surface stabilized ferroelectric liquid crystal (SSFLC) type, and the like. Among them, the TN type and STN type are currently mainstream. Among these, in the STN type, the capacity can be increased to some extent due to the improvement of the driving method, etc., but it is no longer limited to the recent demand for large display capacity. Therefore, active matrix methods such as MIM (Metal Insurator Metal) method using a two-terminal nonlinear element with a threshold characteristic for each display pixel and TFT (ThinFilmTransistor) method using a three-terminal active element have been put into practical use to increase the capacity. It is developing rapidly.

  The liquid crystal materials used in these liquid crystal display systems are required to have various characteristics depending on the characteristics of each display system, but it is common to operate in a wide temperature range and to respond quickly. This is a particularly important requirement.

  The response time can be shortened by lowering the viscosity of the liquid crystal composition, but the response time can also be increased by the following method. In the TN liquid crystal display, there is a proportional relationship between the square of the cell thickness (d) and the response time (τ), and a liquid crystal element having a quick response can be obtained by reducing the value of d. However, in order to prevent the occurrence of interference fringes on the cell surface, which causes the appearance of the cell to be damaged, the product Δn · d of the refractive index anisotropy (Δn) of the liquid crystal material filling the cell and the cell thickness is Must be set to a specific value. In a practically used liquid crystal cell, the value of Δn · d is set to 0.5, 1.0, 1.6, or 2.2. Thus, since the value of Δn · d is set to a constant value, a liquid crystal material having a large value of Δn is required to reduce d. In addition, a liquid crystal material having a large Δn is also required for a polymer-dispersed liquid crystal display element that requires strong cloudiness.

  Next, in order to enable driving in a wide temperature range, a compound having a high nematic phase-isotropic liquid phase transition temperature (TN-I) is required. For this purpose, tricyclic or tetracyclic compounds are usually used, but tricyclic compounds are desirable in order to suppress an increase in viscosity. It is also important that these compounds have excellent compatibility with the host liquid crystal.

  In addition to these required characteristics, the liquid crystal composition for TFT is required to have a high voltage holding ratio. At present, as a compound having a large Δn, a tolan type, a pyrimidine type or a terphenyl type is known. Among these tolan type compounds, for example, the compound (a) is particularly known as a compound having a high TN-I. ing.

Phase transition temperature (° C) C150N207I
(Of the above, C represents a crystalline phase, N represents a nematic phase, and I represents an isotropic liquid phase.)
This compound (a) has a large Δn and a high TN-I, and when mixed with a currently used host liquid crystal, the TN-I can be increased and Δn can be increased. However, since the compound (a) has a very high melting point and poor compatibility with the host liquid crystal, the amount that can be used is extremely limited, and the characteristics of the compound cannot be sufficiently extracted.
Compound (b) is known as a tolan compound with improved compatibility.

Phase transition temperature (° C) C89N148I
(Of the above, C represents a crystalline phase, N represents a nematic phase, and I represents an isotropic liquid phase.)
Similarly, this compound (b) has a high TN-I, a good compatibility with the host liquid crystal, and can raise the TN-I. However, Δn is smaller than that of the compound (a), which is not sufficient.
Accordingly, a tolan compound having a high TN-I and excellent compatibility with the host liquid crystal and a compound having a large Δn have been desired.

JP-A-4-234828

  The problem to be solved by the present invention is to provide a novel liquid crystal compound excellent in compatibility with the host liquid crystal, having a high TN-I and a large Δn, and a novel synthetic intermediate thereof, and further comprising the novel liquid crystal compound Another object of the present invention is to provide a liquid crystal composition having a wide temperature range showing a liquid crystal phase and a large Δn.

  In order to solve the above problems, the present invention provides a compound represented by the general formula (I)

(In the formula, R represents an alkyl group having 1 to 10 carbon atoms, X and Y each independently represents a fluorine atom or a hydrogen atom, Z represents an alkyl group having 1 to 10 carbon atoms, and 1 carbon atom) To 10 alkoxyl groups, fluorine atoms, chlorine atoms, trifluoromethyl groups, trifluoromethoxy groups, difluoromethoxy groups or 2,2,2-trifluoroethoxy groups). Useful as an intermediate for general formula (II)

(Wherein R represents an alkyl group having 1 to 10 carbon atoms).

The compound represented by the general formula (I) of the present invention has a high maximum temperature of the nematic phase and is excellent in compatibility with a host liquid crystal currently widely used as a liquid crystal, and a liquid crystal composition containing the compound has a TN − It is possible to increase I and Δn, and to obtain a high voltage holding ratio.
Therefore, the compound represented by the general formula (I) of the present invention is a liquid crystal material useful for a liquid crystal display such as a word processor or a liquid crystal television in which high-speed response is important.

  Among the compounds represented by the general formula (I) according to the present invention, Z is an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a fluorine atom, a chlorine atom, or a trifluoromethoxy group. The compound represented by the above general formula (I) is preferable, and among them, Z is a linear alkyl group having 1 to 5 carbon atoms, a linear alkoxyl group having 1 to 5 carbon atoms, fluorine The compound represented by the general formula (I), which is an atom, a chlorine atom, or a trifluoromethoxy group, is preferable.

  In the compound of the general formula (I) of the present invention, X and Y are preferably both hydrogen atoms. In addition, it is preferable that at least one of X and Y is a fluorine atom, and in this case, Z is more preferably a fluorine atom or a chlorine atom.

  Furthermore, in the compound of the general formula (I) of the present invention, R is preferably a linear alkyl group having 1 to 5 carbon atoms. The compound represented by the general formula (I) according to the present invention can be produced, for example, as follows.

(In the formulas (I) to (VIII), R, X, Y and Z have the same meaning as in formula (I), and R ′ is 2 fewer than the number of carbon atoms in R. Represents an alkyl group or a hydrogen atom, and Q represents an iodine atom or a bromine atom.)
First step: 4-Formyl-2-fluorobiphenyl is produced by reacting 4-bromo-2-fluorobiphenyl with magnesium to form a Grignard reagent and reacting with N, N-dimethylformamide (DMF).
Second step: 4-formyl-2-fluorobiphenyl is reacted with a Wittig reaction reagent of general formula (III) to produce a compound of general formula (IV).
Third step: The compound of general formula (IV) is catalytically reduced with hydrogen in the presence of a catalyst such as palladium carbon (Pd / C) to produce the compound of general formula (V).
Fourth step: The compound of general formula (V) is reacted with acetyl chloride in the presence of a Lewis acid catalyst such as aluminum chloride to produce a compound of general formula (VI).
Fifth step: A compound of general formula (VII) is produced by chlorinating a compound of general formula (VI) with phosphorus pentachloride.
Sixth step: 2-fluoro-4-alkyl-4′-ethynylbiphenyl of the general formula (II) is produced by dehydrochlorinating the compound of the general formula (VII) with a base such as t-butoxy potassium.
Seventh step: 2-fluoro-4-alkyl-4′-ethynylbiphenyl of the general formula (II) and a compound of the general formula (VIII) are reacted in the presence of palladium and a copper catalyst to give a general formula ( The compound of I) is prepared.

Here, when R is a methyl group in the general formula (I), for example, the compound of the general formula (V) can be obtained by reducing 4-formyl-2-fluorobiphenyl with hydrazine in the presence of a strong base. From this, the compounds of general formula (I) and general formula (II) of the present invention can be produced in the same manner.
During the above production process, 2-fluoro-4-alkyl-4′-ethynylbiphenyl represented by the general formula (II) is a novel compound useful as a synthetic intermediate for the compound of the general formula (I). This compound is also provided.

  Examples of typical compounds represented by the general formula (I) thus produced are listed in Table 1.

(In Table 1, C represents a crystalline phase, SA represents a smectic A phase, N represents a nematic phase, and I represents an isotropic liquid phase.)
The nematic liquid crystal composition containing the compound of general formula (I) according to the present invention has the following excellent characteristics.
An example is shown below.

  Currently widely used host liquid crystal (A)

  TN-I (nematic phase upper limit temperature) of (wherein the cyclohexane ring is in a trans configuration) was 55 ° C., and Δn was 0.092.

  Table 2 shows the nematic phase transition temperature (TN-I) and refraction of the liquid crystal composition prepared using the above-mentioned host liquid crystal (A) and each of the compounds (I-1) to (I-7) in Table 1. This shows the anisotropy of the rate (Δn) and the content of each compound of (I50-1) to (I-7) in the prepared liquid crystal composition. For comparison, the liquid crystal composition containing the compound (a) and the compound (b) was measured in the same manner, and TN-I and Δn were shown.

  (In Table 2, for example, composition No. 1 is a liquid crystal composition comprising 20% by weight of compound (I-1) and 80% by weight of host liquid crystal (A).) From Table 2. The compound (I-1) is excellent in compatibility with the host liquid crystal and does not cause precipitation or phase separation even when mixed at 20% by weight. Moreover, it is clear that TN-I rises to 69 ° C. and Δn rises significantly to 0.141.

  On the other hand, the comparative compound (a) having a structure similar to (I-1) has poor compatibility with the host liquid crystal, so the amount that can be mixed is limited to 10% by weight. It could only be raised to 118.

  Next, the compound of (I-2) is also excellent in compatibility with the host liquid crystal, and no precipitation or phase separation occurs even when 20% by weight is mixed. Moreover, it is clear that TN-I increases to 63 ° C. and Δn increases to 0.134.

  On the other hand, the comparative compound (b) having a similar structure to (I-2) is excellent in compatibility with the host liquid crystal and does not cause precipitation or phase separation even when mixed at 20% by weight. Moreover, TN-I is raised to 70 ° C. However, Δn is considerably smaller than that of the compound (I-2) having a similar structure as 0.121.

  Further, a TFT host liquid crystal (B) having the following composition was prepared.

(In the formula, the cyclohexane ring is in the trans configuration.)
TN-I of this host liquid crystal (B) was 117 ° C., Δn was 0.090, and the voltage holding ratio was 99% or more. The TN-I of the liquid crystal composition comprising 70% by weight of the host liquid crystal (B) and 30% by weight of the compound (I-1) increased to 123 ° C., and Δn increased to 0.166. Further, when the voltage holding ratio of this composition was measured, it was 99% or more, and it could be used for TFT.

From the top, the compound represented by the general formula (I) according to the present invention is excellent in compatibility with other liquid crystal materials, and can increase TN-I of the composition and increase Δn by the addition. It can be easily understood that the compound has characteristics superior to those of the compounds.
As a preferable representative example of a nematic liquid crystal compound that can be used as a liquid crystal composition by mixing with the compound represented by the general formula (I) as described above, for example, 4-substituted benzoic acid-4-substituted Phenyl, 4-substituted cyclohexanecarboxylic acid-4-substituted phenyl, 4-substituted cyclohexanecarboxylic acid-4′-substituted biphenylyl, 4- (4-substituted cyclohexanecarbonyloxy) benzoic acid-4-substituted phenyl, 4- (4- Substituted cyclohexyl) benzoic acid-4-substituted phenyl, 4- (4-substituted cyclohexyl) benzoic acid-4-substituted cyclohexyl, 4,4′-substituted biphenyl, 1- (4-substituted phenyl) -4-substituted cyclohexane, 4 , 4 "-substituted terphenyl, 1- (4'-substituted biphenylyl) -4-substituted cyclohexane, 1- (4- Substituted cyclohexyl) -4- (4-substituted phenyl) cyclohexane, 2- (4-substituted phenyl) -5-substituted pyrimidine, 2- (4-substituted biphenylyl) -5-substituted pyrimidine, 1- (4-substituted cyclohexyl) 2- (4-substituted cyclohexyl) ethane, 1- (4-substituted cyclohexyl) -2- (4-substituted phenyl) ethane, 1- [4- (4-substituted cyclohexyl) cyclohexyl] -2- (4-substituted Phenyl) ethane, 1- [4- (4-substituted phenyl) cyclohexyl] -2- (4-substituted cyclohexyl) ethane, 1- (4-substituted phenyl) -2- (4-substituted phenyl) ethyne, 1- [ 4- (4-substituted cyclohexyl)]-2- (4-substituted phenyl) ethyne and the like can be mentioned.

The following examples further illustrate the present invention. However, the present invention is not limited to these examples.
Example 1 Synthesis of 2-fluoro-4-propyl-4′-ethynylbiphenyl (1) Synthesis of 4-formyl-2-fluorobiphenyl

Magnesium (5.5 g) was suspended in tetrahydrofuran (THF) (25 ml), and 2-fluoro-4-bromobiphenyl (50 g) in THF (250 ml) was added dropwise at a rate such that THF was gently refluxed, followed by stirring at room temperature for 1 hour. After the completion of the reaction, a solution of 22.0 g of N, N-dimethylformamide (DMF) in 75 ml of THF was added dropwise at room temperature, and the mixture was further stirred at room temperature for 1 hour. After completion of the reaction, extraction was performed with 250 ml of toluene, and the organic layer was washed successively with saturated sodium hydrogen carbonate, water and saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was purified using silica gel column chromatography (solvent: hexane / ethyl acetate = 9/1) to obtain 41.9 g of 4-formyl-2-fluorobiphenyl.
(2) Synthesis of 2-fluoro-4- (1-propenyl) biphenyl

100 g of ethyltriphenylphosphonium iodide was suspended in 400 ml of THF and cooled to 10 ° C. or lower. 26.8 g of t-butoxy potassium was added, and a 150 ml solution of 4-formyl-2-fluorobiphenyl obtained in (1) above was added dropwise at a rate such that the liquid temperature did not exceed 10 ° C., and the mixture was further stirred at the same temperature for 1 hour. . After completion of the reaction, 400 ml of water was added, the organic layer was separated, and the solvent was distilled off. 200 ml of hexane was added, insoluble matters were filtered off, and the filtrate was washed successively with water and saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was purified using silica gel column chromatography (solvent: hexane) to obtain 36.6 g of 2-fluoro-4- (1-propenyl) biphenyl.
(3) Synthesis of 2-fluoro-4-propylbiphenyl

36.6 g of 2-fluoro-4- (1-propenyl) biphenyl obtained in (2) above is dissolved in 200 ml of ethyl acetate, 4 g of 5% palladium carbon (Pd / C) is added, and hydrogen pressure is 1 atm at room temperature. Contact reduction. The catalyst was filtered off and the solvent was distilled off to obtain 36.5 g of 2-fluoro-4-propylbiphenyl.
(4) Synthesis of 2-fluoro-4-propyl-4′-acetylbiphenyl

2-Fluoro-4-propylbiphenyl obtained in (3) above is dissolved in 50 ml of dichloromethane and cooled to 10 ° C. or lower, then 8.1 g of anhydrous aluminum chloride is added, and acetyl chloride 4 is maintained at a rate keeping 10 ° C. or lower. 0.1 g of dichloromethane in 16 ml was added dropwise. The mixture was further stirred at the same temperature for 1 hour and added to ice water. Extraction was performed with 100 ml of hexane, and the organic layer was washed successively with saturated sodium carbonate, water, and saturated brine. After drying over anhydrous sodium sulfate, the solvent was distilled off to obtain 11.8 g of 2-fluoro-4-propyl-4′-acetylbiphenyl.
(5) Synthesis of 2-fluoro-4-propyl-4 ′-(1-chloroethenyl) biphenyl

11.5 g of phosphorus pentachloride is suspended in 50 ml of carbon tetrachloride, and a solution of 11.8 g of 2-fluoro-4-propyl-4′-acetylbiphenyl obtained in (4) above is added dropwise over 30 minutes. The mixture was further stirred at room temperature for 10 hours. After completion of the reaction, this solution was slowly poured into 100 ml of water, and the organic layer was separated and dried over anhydrous sodium sulfate. The solvent was distilled off, and the residue was purified using silica gel column chromatography (solvent: hexane) to obtain 3.8 g of 2-fluoro-4-propyl-4 ′-(1-chloroethenyl) biphenyl.
(6) Synthesis of 2-fluoro-4-propyl-4′-ethynylbiphenyl

3.8 g of 2-fluoro-4-propyl-4 ′-(1-chloroethenyl) biphenyl obtained in (5) above was dissolved in 20 ml of DMF, and 1.6 g of potassium t-butoxy was added at such a rate that the liquid temperature did not exceed 40 ° C. Added in. Further, the mixture was stirred at room temperature for 1 hour, and 20 ml of water was added. Extraction was performed with 40 ml of ethyl acetate, and the organic layer was washed successively with water and saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off, and the residue was purified using silica gel column chromatography (solvent: hexane) to obtain 2.0 g of 2-fluoro-4-propyl-4′-ethynylbiphenyl. The melting point of this compound was 42.4 ° C.
Reference Example 2 Synthesis of 2-fluoro-4-propyl-4 ′-(4-fluorophenylethynyl) biphenyl

2.0 g of 2-fluoro-4-propyl-4′-ethynylbiphenyl obtained in Example 1 and 4-fluoro-1-iodobenzene were dissolved in 20 ml of DMF and 2 ml of triethylamine. Tetrakis (triphenylphosphine) palladium (0) 0.2 g and copper iodide (I) 0.03 g were added, and the mixture was stirred at room temperature for 2 hours. After completion of the reaction, 20 ml of toluene was added, and the organic layer was washed successively with water and saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off, the residue was purified using silica gel column chromatography (solvent: hexane), recrystallized from ethanol, and 2-fluoro-4-propyl-4 ′-(4-fluorophenylethynyl) biphenyl. 0 g was obtained. When the phase transition temperature was measured, the crystal phase was changed to the nematic phase at 92 ° C., and the nematic phase was changed to the isotropic liquid phase at 164 ° C.
Reference Example 3 Synthesis of 2-fluoro-4-propyl-4 ′-(3,4-difluorophenylethynyl) biphenyl (compound of (I-2) in Table 1)

In Reference Example 2, 2-fluoro-4-propyl-4 ′ was used in the same manner as in Reference Example 2 except that 3,4-difluoro-1-bromobenzene was used instead of 4-fluoro-1-iodobenzene. -(3,4-Difluorophenylethynyl) biphenyl was obtained. The phase transition temperature is shown in Table 1.
Reference Example 4 Synthesis of 2-fluoro-4-propyl-4 ′-(3,4,5-trifluorophenylethynyl) biphenyl (compound of (I-3) in Table 1)

In Reference Example 2, 2-fluoro-4-propyl was prepared in the same manner as in Reference Example 2, except that 3,4,5-trifluoro-1-bromobenzene was used instead of 4-fluoro-1-iodobenzene. -4 ′-(3,4,5-trifluorophenylethynyl) biphenyl was obtained. The phase transition temperature is shown in Table 1.
Reference Example 5 Synthesis of 2-fluoro-4-propyl-4 ′-(4-trifluoromethoxyphenylethynyl) biphenyl (compound of (I-4) in Table 1)

In Reference Example 2, in the same manner as in Reference Example 2, except that 4-trifluoromethoxy-1-bromobenzene was used instead of 4-fluoro-1-iodobenzene, 2-fluoro-4-propyl-4 ′ -(4-Trifluoromethoxyphenylethynyl) biphenyl was obtained. The phase transition temperature is shown in Table 1.
Reference Example 6 Synthesis of 2-fluoro-4-propyl-4 ′-(3-fluoro-4-chlorophenylethynyl) biphenyl (compound of (I-5) in Table 1)

In Reference Example 2, in the same manner as in Reference Example 2, except that 3-fluoro-4-chloro-1-bromobenzene was used instead of 4-fluoro-1-iodobenzene, 2-fluoro-4-propyl- 4 ′-(3-Fluoro-4-chlorophenylethynyl) biphenyl was obtained. The phase transition temperature is shown in Table 1.
Reference Example 7 Synthesis of 2-fluoro-4-propyl-4 ′-(4-methylphenylethynyl) biphenyl (compound of (I-6) in Table 1)

In Reference Example 2, 2-fluoro-4-propyl-4 ′-(4-methylphenyl) was obtained in the same manner as in Reference Example 2 except that 4-iodotoluene was used instead of 4-fluoro-1-iodobenzene. Ethynyl) biphenyl was obtained. The phase transition temperature is shown in Table 1.
Reference Example 8 Synthesis of 2-fluoro-4-propyl-4 ′-(4-methoxyphenylethynyl) biphenyl (compound of (I-7) in Table 1)

In Reference Example 2, 2-fluoro-4-propyl-4 ′-(4-methylmethoxy) was prepared in the same manner as in Reference Example 2 except that 4-iodoanisole was used instead of 4-fluoro-1-iodobenzene. Phenylethynyl) biphenyl was obtained. The phase transition temperature is shown in Table 1.
Reference Example 9 Preparation of liquid crystal composition (1)
A host liquid crystal (A) having the following composition was prepared.

(In the formula, the cyclohexane ring represents a trans configuration.)
The TN-I and Δn of the host liquid crystal (A) were measured and were as follows.
TN-I55 ℃
Δn 0.092
TN-I and Δn of a liquid crystal composition comprising 80% by weight of the host liquid crystal (A) and 20% by weight of 2-fluoro-4-propyl-4 ′-(4-fluorophenylethynyl) biphenyl synthesized in Reference Example 2 It was as follows when measured.
TN-I69 ℃
Δn0.141
From the above results, it can be understood that the compound synthesized in Reference Example 2 increases TN-I of the composition obtained when mixed with the host liquid crystal and also increases Δn.
(Comparative Example 1) For comparison, 20% by weight of the aforementioned compound (a) having 80% by weight of the host liquid crystal (A) and a similar structure to the compound of (I-1), high TN-I, and large Δn A comparative composition consisting of was immediately deposited at room temperature. Further, when the amount of the compound (a) mixed with the host liquid crystal (A) was reduced, no precipitation occurred at 10% by weight or less. Therefore, the TN-I and Δn of the liquid crystal composition comprising 90% by weight of the host liquid crystal (A) and 10% by weight of the compound (a) were measured and found to be as follows.
TN-I69 ℃
Δn0.118
From the above results, it can be understood that Δn cannot be increased greatly because compound (a) has a low ratio of being mixed with the host liquid crystal.
Reference Example 10 Preparation of liquid crystal composition (2)
A liquid crystal composition composed of 80% by weight of the host liquid crystal (A) and 20% by weight of 2-fluoro-4-propyl-4 ′-(3,4-difluorophenylethynyl) biphenyl synthesized in Reference Example 3 was prepared, and TN -I and Δn were measured and were as follows.
TN-I63 ℃
Δn0.134
From the above results, it can be understood that the compound synthesized in Reference Example 3 increases TN-I of the composition obtained when mixed with the host liquid crystal and also increases Δn.
(Comparative Example 2) For comparison, the host liquid crystal (A) has a structure similar to that of the compound of (A) 80% and (I-2), has a high TN-I and a large Δn. The following comparative liquid crystal composition was prepared, and TN-I and Δn were measured.
TN-I 70 ℃
Δn0.121
From the above results, it can be understood that the compound (b) greatly increases TN-I but does not increase Δn.
Reference Example 11 Preparation of liquid crystal composition (3)
A liquid crystal composition comprising 80% by weight of the host liquid crystal (A) and 20% by weight of 2-fluoro-4-propyl-4 ′-(3,4,5-trifluorophenylethynyl) biphenyl synthesized in Reference Example 4 was prepared. Then, TN-I and Δn were measured and were as follows.
TN-I 58 ℃
Δn0.127
From the above results, it can be understood that the compound synthesized in Reference Example 4 increases TN-I of the composition obtained when mixed with the host liquid crystal and also increases Δn.
Reference Example 12 Preparation of liquid crystal composition (4)
A liquid crystal composition composed of 80% by weight of the host liquid crystal (A) and 20% by weight of 2-fluoro-4-propyl-4 ′-(4-trifluoromethoxyphenylethynyl) biphenyl synthesized in Reference Example 5 was prepared, and TN -I and Δn were measured and were as follows.
TN-I 71 ℃
Δn 0.135
From the above results, it can be understood that the compound synthesized in Reference Example 5 increases TN-I of the composition obtained when mixed with the host liquid crystal and also increases Δn.
Reference Example 13 Preparation of liquid crystal composition (5)
A liquid crystal composition comprising 80% by weight of host liquid crystal (A) and 20% by weight of 2-fluoro-4-propyl-4 ′-(3-fluoro-4-chlorophenylethynyl) biphenyl synthesized in Reference Example 6 was prepared. TN-I and Δn were measured and were as follows.
TN-I63 ℃
Δn0.143
From the above results, it can be understood that the compound synthesized in Reference Example 6 increases TN-I of the composition obtained when mixed with the host liquid crystal and also increases Δn.
Reference Example 14 Preparation of liquid crystal composition (6)
A liquid crystal composition comprising 85% by weight of the host liquid crystal (A) and 15% by weight of 2-fluoro-4-propyl-4 ′-(4-methylphenylethynyl) biphenyl synthesized in Reference Example 7 was prepared, and TN-I And Δn were measured as follows.
TN-I 71 ℃
Δn0.136
From the above results, it can be understood that the compound synthesized in Reference Example 7 increases TN-I of the composition obtained when mixed with the host liquid crystal and also increases Δn.
Reference Example 15 Preparation of liquid crystal composition (7)
A liquid crystal composition comprising 85% by weight of host liquid crystal (A) and 15% by weight of 2-fluoro-4-propyl-4 ′-(4-methoxyphenylethynyl) biphenyl synthesized in Reference Example 8 was prepared, and TN-I And Δn were measured as follows.
TN-I 74 ℃
Δn0.139
From the above results, it can be understood that the compound synthesized in Reference Example 8 increases TN-I of the composition obtained when mixed with the host liquid crystal and also increases Δn.
Reference Example 16 Preparation of liquid crystal composition (8)
A host liquid crystal (B) for TFT having the following composition was prepared.

(In the formula, the cyclohexane ring represents a trans configuration.)
The TN-I point, Δn, and voltage holding ratio of this host liquid crystal (B) were measured and found to be as follows.
TN-I 117 ℃
Δn 0.090
A voltage holding ratio of 99% or more A liquid crystal composition comprising 70% by weight of the host liquid crystal (B) and 30% by weight of 2-fluoro-4-propyl-4 ′-(4-fluorophenylethynyl) biphenyl synthesized in Reference Example 2. Was prepared, and the TN-I point, Δn, and voltage holding ratio were measured.
TN-I123 ℃
Δn0.166
From the result that the voltage holding ratio is 99% or more, the compound synthesized in Reference Example 2 increases the TN-I of the composition obtained when mixed with the host liquid crystal for TFT, increases Δn, and increases the voltage. It can be understood that the retention rate is maintained.
Reference Example 17 Preparation of liquid crystal composition (9)
A liquid crystal composition comprising 70% by weight of the host liquid crystal (B) and 30% by weight of 2-fluoro-4-propyl-4 ′-(4-trifluoromethoxyphenylethynyl) biphenyl synthesized in Reference Example 5 was prepared, and TN When -I, Δn, and voltage holding ratio were measured, they were as follows.
TN-I126 ℃
Δn0.156
From the result that the voltage holding ratio is 99% or more, the compound synthesized in Reference Example 5 increases the TN-I of the composition obtained when mixed with the host liquid crystal for TFT, increases Δn, and increases the voltage. It can be understood that the retention rate is maintained.
Reference Example 18 Preparation of liquid crystal composition (10)
A liquid crystal composition comprising 70% by weight of host liquid crystal (B) and 30% by weight of 2-fluoro-4-propyl-4 ′-(3-fluoro-4-chlorophenylethynyl) biphenyl synthesized in Reference Example 6 was prepared, TN-I, Δn, and voltage holding ratio were measured and were as follows.
TN-I122 ℃
Δn0.169
From the result that the voltage holding ratio is 99% or more, the compound synthesized in Reference Example 6 increases the TN-I of the composition obtained when mixed with the host liquid crystal for TFT, increases Δn, and increases the voltage. It can be understood that the retention rate is maintained.
Reference Example 19 Preparation of liquid crystal composition (11)
A liquid crystal composition comprising 75% by weight of host liquid crystal (B) and 25% by weight of 2-fluoro-4-propyl-4 ′-(4-methylphenylethynyl) biphenyl synthesized in Reference Example 7 was prepared, and TN-I , Δn and voltage holding ratio were measured, and were as follows.
TN-I 130 ℃
Δn0.157
From the result that the voltage holding ratio is 99% or more, the compound synthesized in Reference Example 7 increases the TN-I of the composition obtained when mixed with the host liquid crystal for TFT, increases Δn, and increases the voltage. It can be understood that the retention rate is maintained.
Reference Example 20 Preparation of liquid crystal composition (12)
A liquid crystal composition comprising 85% by weight of host liquid crystal (B) and 15% by weight of 2-fluoro-4-propyl-4 ′-(4-methoxyphenylethynyl) biphenyl synthesized in Reference Example 8 was prepared, and TN-I , Δn and voltage holding ratio were measured, and were as follows.
TN-I 127 ℃
Δn 0.135
From the result that the voltage holding ratio is 99% or more, the compound synthesized in Reference Example 8 increases the TN-I of the composition obtained when mixed with the host liquid crystal for TFT, increases Δn, and increases the voltage. It can be understood that the retention rate is maintained.

Claims (1)

Formula (II)

(Wherein R represents an alkyl group having 3 carbon atoms ).