JPH11246451A - Fluoroterphenyl derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new compound which is a liquid crystal compound having a great refractive index anisotropy and a great permittivity anisotropy and excellent even in compatibility with other liquid crystal compounds and capable of providing a liquid crystal composition having a wide liquid crystal temperature range and enabling high-speed response and low-voltage driving. SOLUTION: This compound is represented by formula I (R is a 1-10C alkyl or a 3-10C alkenyl; Z is fluorine, chlorine or the like; X<1> and X<2> are each hydrogen or fluorine), e.g. 3,4,5,2"-tetrafluoro-4"-propyl-p-terphenyl. The compound represented by formula I is obtained by initially reacting 2-fluoro-4-bromo-4'- iodobiphenyl with an organometallic reactant represented by formula II (W is MgI, Li or the like) in the presence of a transition metal catalyst, providing a compound represented by formula III, then reacting the resultant compound with an alkyne compound represented by the formula R'C≡CH (R' is an alkyl having a smaller number of carbon atoms than R by 2) in the presence of a palladium-based catalyst and a copper(I) catalyst and subsequently catalytically reducing the triple bond of the resultant product with hydrogen in the presence of a transition metal catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel liquid crystalline compound useful as a nematic liquid crystal material for electro-optical liquid crystal display, in particular, a low-voltage drive and high-speed response, and a liquid crystal containing the same. Composition.

[0002]

2. Description of the Related Art Liquid crystal display elements have been used in various measuring instruments, such as watches and calculators, automobile panels, word processors, electronic organizers, printers, computers, televisions, and the like. Typical liquid crystal display methods are TN (twisted nematic) type and S type.
TN (super twisted nematic) type, DS (dynamic light scattering) type,
There are GH (guest / host) type or FLC (ferroelectric liquid crystal), etc., and the driving method is generally multiplex driving instead of conventional static driving, and moreover, simple matrix method, recently active matrix method is practical. Has been

According to these display systems and driving systems, various characteristics are required as a liquid crystal material. Among them, higher response and lowering of driving voltage have recently been particularly emphasized. The physical properties required of the liquid crystal material to speed up the response are directly (i) reducing the viscosity or (ii) increasing the elastic constant. Indirectly (ii
i) It is also very effective to reduce the cell thickness. However, in the liquid crystal element, in order to prevent coloring and unevenness due to the generation of interference fringes, the cell thickness (d) and the refractive index anisotropy (Δ
n) is a constant (0.5, 1.0, 1.
6, 2.2, usually the former. ) Must be set. Therefore, in order to reduce the cell thickness, it is important that the liquid crystal material has a large refractive index anisotropy (Δn). Further, in a light reflection type or light scattering type liquid crystal display device, a large refractive index anisotropy (Δn) is particularly important for increasing the contrast.

On the other hand, in order to enable low-voltage driving by lowering the threshold voltage, it is necessary to (i) increase the dielectric anisotropy (Δε) or (ii) reduce the elastic constant. However, when the elastic constant is reduced as described above, the response is adversely affected.

Therefore, in order to achieve both high-speed response and low-voltage driving, a so-called P having a large dielectric anisotropy (Δε) is required.
It is important that the liquid crystal has a large refractive index anisotropy (Δn) and a small viscosity.

[0006] In addition, it is always important for a liquid crystal material to exhibit a wide temperature range, and it is also important that the compound has excellent compatibility with other liquid crystal compounds and does not cause phase separation.

Accordingly, the refractive index anisotropy (Δn) is large,
In addition, a low-viscosity liquid crystal compound having a large dielectric anisotropy (Δε) and excellent compatibility with other liquid crystal compounds is desired. Currently, these conditions are relatively well satisfied3
Examples of the cyclic liquid crystal compound include compounds represented by general formula (II)

[0008]

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(Wherein, ^Ra represents an alkyl group). However, although the compound of (II) has a sufficiently large refractive index anisotropy (Δn), it cannot be said that the dielectric anisotropy (Δε) is sufficiently large. Has a drawback that precipitation is likely to occur when a liquid crystal composition is prepared due to poor compatibility. Therefore, a liquid crystal compound having a large refractive index anisotropy (Δn), a large dielectric anisotropy (Δε), and excellent compatibility with other liquid crystal compounds is desired.

[0010]

An object of the present invention is to provide a terphenyl derivative having a large refractive index anisotropy (Δn) and a dielectric anisotropy (Δn). A liquid crystal compound having a large Δε) and excellent compatibility with other liquid crystal compounds is provided, and a liquid crystal composition having a wide liquid crystal temperature range and capable of high-speed response and low-voltage driving is provided by using the compound. It is in.

[0011]

The present invention has been made in order to solve the above problems. General formula (I)

[0012]

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(Wherein R represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 3 to 10 carbon atoms;
Is a fluorine atom, a chlorine atom, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group or 2,
It represents a 2,2-trifluoroethoxy group, and X ¹ and X ² each independently represent a hydrogen atom or a fluorine atom. A) a fluoroterphenyl derivative represented by the formula: 2. 2. The fluoroterphenyl derivative according to the above 1, wherein in the general formula (I), Z is a fluorine atom or a trifluoromethoxy group. 3. 3. The fluoroterphenyl derivative according to the above 1 or 2, wherein in the general formula (I), R represents a linear alkyl group having 1 to 7 carbon atoms or a linear alkenyl group having 4 to 7 carbon atoms. 4. 4. The fluoroterphenyl derivative according to the above 1, 2, or 3, wherein in formula (I), at least one of X ¹ and X ² represents a fluorine atom. 5. 5. The fluoroterphenyl derivative according to the above 4, wherein in formula (I), X ¹ and X ² both represent a fluorine atom. 6. A liquid crystal composition containing the compound represented by the general formula (I) according to any one of the above 1 to 5. Was found as a means for solving the above-mentioned problem.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described below. The present invention relates to a compound of the formula (I)

[0015]

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There is provided a fluoroterphenyl derivative represented by the formula: In the formula, R represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 3 to 10 carbon atoms, but a linear alkyl group having 1 to 7 carbon atoms or 4 to 7 carbon atoms.
Is preferable, and the alkenyl group is preferably a 3-alkenyl group, and particularly preferably has 2 to 5 carbon atoms.
Is preferred as a linear alkyl group or a 3-butenyl group. Z
Is a fluorine atom, a chlorine atom, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group or 2,
It represents a 2,2-trifluoroethoxy group, preferably a fluorine atom or a trifluoromethoxy group, particularly preferably a fluorine atom. X ¹ and X ² each independently represent a hydrogen atom or a fluorine atom, but in order to enhance the effect of reducing the threshold voltage, at least one of them is preferably fluorine, and both are preferably fluorine atoms. More preferred.

The compound of the formula (I) can be produced according to the following steps. That is, the formula (III)

[0018]

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2-fluoro-4-bromo- represented by the formula:
4′-iodobiphenyl (this compound is 2-fluoro-
It can be easily obtained by directly iodinating 4-bromobiphenyl. ) And general formula (IV)

[0020]

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(Wherein X ¹ , X ² and Z have the same meanings as in the general formula (I), and W represents MgI, MgBr, Mg
It represents an atomic group containing a metal directly connected to a benzene ring such as Cl, Li, and B (OH) ₂ . ) Is reacted with an organometallic reagent represented by the following formula (V):

[0022]

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The compound of the formula As the transition metal catalyst, palladium (0), palladium (II), and nickel (II) are preferable, and in particular, tetrakis (triphenylphosphine)
Palladium (0) complexes such as palladium (0), and dichloro [1,2-bis (diphenylphosphino) ethane] nickel (II), dichloro [1,2-bis (diphenylphosphino) propane] nickel (II) And the like are preferred.

The compound of the general formula (V) and the compound of the general formula (V
I)

[0025]

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(R ′ represents an alkyl group having 2 carbon atoms less than R) with an alkyne compound represented by the general formula (VII) in the presence of a palladium catalyst and a copper (I) catalyst. )

[0027]

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(Wherein X ¹ , X ² and Z have the same meaning as in general formula (I), and R ′ has the same meaning as in general formula (VI)). . Here, as the palladium-based catalyst, a palladium (0) complex such as tetrakis (triphenylphosphine) palladium (0),
Dichlorobis (triphenylphosphine) palladium (I
A palladium (II) complex such as palladium (II) and a palladium (II) salt such as palladium (II) chloride can be used, and copper (I) iodide is preferred as the copper (I) catalyst.

Next, the compound of the general formula (I) is produced by catalytically reducing the triple bond of the compound of the formula (VII) with hydrogen in the presence of a transition metal catalyst such as palladium, nickel, platinum, rhodium and ruthenium. be able to. .

Alternatively, the compound of the general formula (V) obtained as an intermediate is converted to dichloro [1,2-bis (diphenylphosphino) ethane] nickel (II), dichloro [1,2
2-bis (diphenylphosphino) propane] nickel
RMgBr in the presence of a nickel (II) complex catalyst such as (II),
Production of a compound of the general formula (I) also by directly reacting with an alkyl (or alkenyl) metal compound such as RMgI or RLi (wherein R has the same meaning as in the general formula (I)). Can be.

Representative compounds of the present invention thus prepared are shown in Table 1 together with their phase transition temperatures.

[0032]

[Table 1]

(In the table, S indicates a smectic phase, Cr indicates a crystal phase, and I indicates an isotropic liquid phase. The phase transition temperature is “° C.”) The compound of the general formula (I) is a liquid crystal. The excellent effects obtained by adding the composition are as follows.

A representative compound represented by the general formula (I), which is shown in Table 1 (No. 1)

[0035]

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30% by weight of the compound (A), a host liquid crystal composition (M) having a wide temperature range and a low viscosity.

[0037]

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Liquid crystal composition (M-1) consisting of 70% by weight
Was prepared. Here, the characteristic value of (M) is as follows. Threshold voltage (Vth): 2.14 V Dielectric anisotropy (Δε): 4.8 Refractive index anisotropy (Δn): 0.090 Here, the threshold voltage (Vth) is a TN cell having a thickness of 6.0 μm. Are measured at 20 ° C., and the dielectric anisotropy and the refractive index anisotropy are all measured at 20 ° C.

On the other hand, the characteristic value of (M-1) was as follows. Threshold voltage (Vth): 1.53 V Dielectric anisotropy (Δε): 7.9 Refractive index anisotropy (Δn): 0.122 Thus, the composition is obtained by mixing the No. 1 compound. Δε became large, and the threshold voltage could be considerably reduced. In addition, the refractive index anisotropy is greatly increased, and the cell thickness can be further reduced. Further, this composition did not cause precipitation of crystals or phase separation even when left at -20 ° C for 1 week. In general, terphenyl derivatives often have poor compatibility with other liquid crystal compounds, but (No.
It is considered that the compatibility of the compound (1) was improved by the effect of the fluorine atom introduced to the side.

On the other hand, a typical compound represented by the general formula (II) is (A)

[0041]

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The characteristic value of the liquid crystal composition (MA) prepared by adding 30% by weight of (M) to (M) was as follows. Threshold voltage (Vth): 1.90 V Dielectric anisotropy (Δε): 7.7 Refractive index anisotropy (Δn): 0.133 Therefore, the compound (A) has an effect of increasing the refractive index anisotropy. Is larger than the compound of (No. 1), but the effect of increasing the dielectric anisotropy does not reach that of (M-1), and therefore, the effect of reducing the threshold voltage is small. Moreover, when the composition was allowed to stand at -20 ° C for one week, precipitation of crystals was observed.

As described above, the compound of the present invention (I)
It has excellent compatibility with other liquid crystal compounds and has a large dielectric anisotropy, which makes it possible to obtain a liquid crystal composition having a low threshold voltage. It is clear that an excellent liquid crystal composition can be obtained, and the effect is superior to that of a conventional compound.

Therefore, the compound of the formula (I) may be in the form of a mixture with another nematic liquid crystal compound in the form of a TN or ST liquid.
It can be suitably used for an N-type or other field-effect display cell, particularly as a liquid crystal material capable of high-speed response and low-voltage driving. Further, by utilizing the large refractive index anisotropy, it is suitable for various display devices such as a light reflection type and a light scattering type. Further, the compound (I) does not contain a strong polar group in the molecule, so that it is easy to obtain a large specific resistance and a high voltage holding ratio, and can be used as a component of an active matrix driving liquid crystal material. It is. The present invention also provides a liquid crystal composition containing at least one compound represented by the general formula (I) as a component thereof.

Preferred representative examples of the nematic liquid crystal compound which can be used as a mixture with the compound (I) in this composition include, 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-substituted phenyl (4-substituted cyclohexyl) benzoate, 4-substituted cyclohexyl 4- (4-substituted cyclohexyl) benzoate, 4,4′-substituted biphenyl, 1- (4
-Substituted cyclohexyl) -4-substituted benzene, 4,4 '
-Substituted bicyclohexane, 1- [2- (4-substituted cyclohexyl) ethyl] -4-substituted benzene, 1- (4-substituted cyclohexyl) -2- (4-substituted cyclohexyl)
Ethane, 4,4 "-substituted terphenyl, 4- (4-substituted cyclohexyl) -4'-substituted biphenyl, 4- [2-
(4-Substituted cyclohexyl) ethyl] -4'-substituted biphenyl, 4- (4-substituted phenyl) -4'-substituted bicyclohexane, 4- [2- (4-substituted cyclohexyl) ethyl] -4'-substituted biphenyl 4- [2- (4-substituted cyclohexyl) ethyl] cyclohexyl-4'-substituted benzene, 4- [2- (4-substituted phenyl) ethyl]-
4'-substituted bicyclohexane, 1- (4-substituted phenylethynyl) -4-substituted benzene, 1- (4-substituted phenylethynyl) -4- (4-substituted cyclohexyl) benzene, 2- (4-substituted phenyl) -5-substituted pyrimidines,
Examples thereof include 2- (4′-substituted biphenylyl) -5-substituted pyrimidine and compounds in which the benzene ring in each of the above compounds has a lateral substituent.

Among them, 4,4'-substituted biphenyl, 1- (4-substituted cyclohexyl) -4-substituted benzene, 4,4'-substituted bicyclohexane, 1- [2- (4- Substituted cyclohexyl)
Ethyl] -4-substituted benzene, 1- (4-substituted cyclohexyl) -2- (4-substituted cyclohexyl) ethane,
4,4 "-substituted terphenyl, 4- (4-substituted cyclohexyl) -4'-substituted biphenyl, 4- [2- (4-substituted cyclohexyl) ethyl] -4'-substituted biphenyl,
4- (4-substituted phenyl) -4'-substituted bicyclohexane, 4- [2- (4-substituted cyclohexyl) ethyl]-
4'-substituted biphenyl, 4- [2- (4-substituted cyclohexyl) ethyl] cyclohexyl-4'-substituted benzene, 4- [2- (4-substituted phenyl) ethyl] -4'-
Substituted bicyclohexane, 1- (4-substituted phenylethynyl) -4-substituted benzene, 1- (4-substituted phenylethynyl) -4- (4-substituted cyclohexyl) benzene and compounds in which the benzene ring is fluorine-substituted Is suitable.

[0047]

EXAMPLES Examples of the present invention are shown below to further explain the present invention. However, the present invention is not limited to these examples.

The structure of the compound was confirmed by nuclear magnetic resonance spectrum (NMR), mass spectrum (MS) and infrared absorption spectrum (IR). “%” Of the composition represents “% by weight”. (Example 1) 3,4,5,2 "-tetrafluoro-
Synthesis of 4 ″ -propyl-p-terphenyl (compound of Table 1 (No. 1)) (1-a) 3,4,5,2 ″ -tetrafluoro-4 ″
Synthesis of -bromo-p-terphenyl

[0049]

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8.7 g of magnesium was suspended in 20 ml of dry tetrahydrofuran (THF). 68 g of 3,4,5-trifluoro-1-bromobenzene
Was added dropwise at a rate at which the solvent continued to reflux gently. After the mixture was further stirred for 1 hour, the mixture was allowed to cool to room temperature to prepare a Grignard reagent. Next, 2-
Fluoro-4-bromo-4'-iodobiphenyl 100
g was dissolved in 400 ml of THF, and 1.6 g of tetrakistriphenylphosphine palladium (0) was added. This is mixed with the Grignard reagent prepared above at 20-40 ° C for 3 hours.
It was dropped over time. After further stirring for 1 hour, water and a small amount of diluted hydrochloric acid were added, and the mixture was extracted with ethyl acetate. After washing with water and then with a saturated saline solution, it was dehydrated and dried with anhydrous sodium sulfate. 104 g of a crude product obtained by distilling off the solvent
Was purified by silica gel column chromatography (hexane) to obtain 101 g of white crystals of 3,4,5,2 "-tetrafluoro-4" -bromo-p-terphenyl. (1-b) 3,4,5,2 "-tetrafluoro-4"
Synthesis of-(1-propynyl) -p-terphenyl

[0051]

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The 3,4,5,2 ″-obtained in the above (1-a)
Tetrafluoro-4 "-bromo-p-terphenyl 30
g to N, N-dimethylformamide (DMF) 150m
1) and 30 ml of triethylamine, and 0.9 g of tetrakistriphenylphosphine palladium (0) and 0.3 g of copper (I) iodide were added. 1-propyne 20-4
It was introduced into the solution at 0 ° C. over 3 hours. A small amount of water was added, extracted with toluene, washed with water and then with a saturated saline solution, and then dried and dried over anhydrous sodium sulfate. The solvent was distilled off, and 30 g of a crude product obtained was purified by silica gel column chromatography (toluene) to obtain 3, 4, 5,
2 "-tetrafluoro-4"-(1-propynyl) -p
26 g of terphenyl white crystals were obtained. (1-c) 3,4,5,2 "-tetrafluoro-4"
Synthesis of -propyl-p-terphenyl

[0053]

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The 3,4,5,2 ″-obtained in the above (1-b)
26 g of tetrafluoro-4 ″-(1-propynyl) -p-terphenyl were dissolved in 250 ml of ethyl acetate, and 5%
5 g of palladium carbon was added, and the mixture was stirred at 20 ° C. and 1 atm of hydrogen pressure for 6 hours. After filtering off the catalyst, 26 g of a crude product obtained by evaporating the solvent was purified by silica gel column chromatography (hexane) to give 3,4,5,2 "-tetrafluoro-4" -propyl-p. -24 g of terphenyl white crystals were obtained. Further, when recrystallized from ethanol and the phase transition temperature was measured, the crystal phase changed from a crystalline phase to a smectic phase at 73 ° C., and changed from a smectic phase to an isotropic liquid phase at 78 ° C.

Similarly, the following compounds can be obtained. 3,4,5,2 "-tetrafluoro-4" -ethyl-p
-Terphenyl 3,4,5,2 "-tetrafluoro-4" -butyl-p
-Terphenyl 3,4,5,2 "-tetrafluoro-4" -pentyl-
p-Terphenyl 3,5,2 "-trifluoro-4-chloro-4" -ethyl-p-terphenyl 3,5,2 "-trifluoro-4-chloro-4" -propyl-p-terphenyl 3,5,2 "-trifluoro-4-chloro-4" -butyl-p-terphenyl 3,5,2 "-trifluoro-4-chloro-4" -pentyl-p-terphenyl 3,5 2 "-trifluoro-4-trifluoromethyl-4" -ethyl-p-terphenyl 3,5,2 "-trifluoro-4-trifluoromethyl-4" -propyl-p-terphenyl 3,5 2 "-trifluoro-4-trifluoromethyl-4" -butyl-p-terphenyl 3,5,2 "-trifluoro-4-trifluoromethyl-4" -pentyl-p-terphenyl 3,5 2 "-trifluoro- -Trifluoromethoxy-4 "-ethyl-p-terphenyl 3,5,2" -trifluoro-4-trifluoromethoxy-4 "-propyl-p-terphenyl 3,5,2" -trifluoro-4 -Trifluoromethoxy-4 "-butyl-p-terphenyl 3,5,2" -trifluoro-4-trifluoromethoxy-4 "-pentyl-p-terphenyl 3,5,2" -trifluoro-4 -Difluoromethoxy-4 "-ethyl-p-terphenyl 3,5,2" -trifluoro-4-difluoromethoxy-4 "-propyl-p-terphenyl 3,5,2" -trifluoro-4-difluoro Methoxy-4 "-butyl-p-terphenyl 3,5,2" -trifluoro-4-difluoromethoxy-4 "-pentyl-p-terphenyl 3,5,2" -tri Fluoro-4- (2,2,2-trifluoroethoxy) -4 "-ethyl-p-terphenyl 3,5,2" -trifluoro-4- (2,2,2-trifluoroethoxy) -4 "-Propyl-p-terphenyl 3,5,2" -trifluoro-4- (2,2,2-trifluoroethoxy) -4 "-butyl-p-terphenyl 3,5,2" -trifluoro -4- (2,2,2-trifluoroethoxy) -4 "-pentyl-p-terphenyl 3,4,2" -trifluoro-4 "-ethyl-p-terphenyl 3,4,2"- Trifluoro-4 "-propyl-p-terphenyl 3,4,2" -trifluoro-4 "-butyl-p-terphenyl 3,4,2" -trifluoro-4 "-pentyl-p-terphenyl 3,2 "-difluoro-4-chloro-4" Ethyl -p
-Terphenyl 3,2 "-difluoro-4-chloro-4" -propyl-
p-terphenyl 3,2 "-difluoro-4-chloro-4" -butyl-p
-Terphenyl 3,2 "-fluoro-4-chloro-4" -pentyl-p
-Terphenyl 3,2 "-difluoro-4-trifluoromethyl-4"
-Ethyl-p-terphenyl 3,2 "-difluoro-4-trifluoromethyl-4"
-Propyl-p-terphenyl 3,2 "-difluoro-4-trifluoromethyl-4"
-Butyl-p-terphenyl 3,2 "-difluoro-4-trifluoromethyl-4"
-Pentyl-p-terphenyl 3,2 "-fluoro-4-trifluoromethoxy-4"
-Ethyl-p-terphenyl 3,2 "-difluoro-4-trifluoromethoxy-
4 "-propyl-p-terphenyl 3,2" -difluoro-4-trifluoromethoxy-
4 "-butyl-p-terphenyl 3,2" -difluoro-4-trifluoromethoxy-
4 "-pentyl-p-terphenyl 3,2" -difluoro-4-difluoromethoxy-4 "
-Ethyl-p-terphenyl 3,2 "-difluoro-4-difluoromethoxy-4"
-Propyl-p-terphenyl 3,2 "-difluoro-4-difluoromethoxy-4"
-Butyl-p-terphenyl 3,2 "-difluoro-4-difluoromethoxy-4"
-Pentyl-p-terphenyl 3,2 "-difluoro-4- (2,2,2-trifluoroethoxy) -4" -ethyl-p-terphenyl 3,2 "-difluoro-4- (2,2 , 2-trifluoroethoxy) -4 "-propyl-p-terphenyl 3,2" -difluoro-4- (2,2,2-trifluoroethoxy) -4 "-butyl-p-terphenyl 3,2 "-Difluoro-4- (2,2,2-trifluoroethoxy) -4" -pentyl-p-terphenyl 4,2 "-difluoro-4" -ethyl-p-terphenyl 4,2 "-difluoro- 4 "-propyl-p-terphenyl 4,2" -difluoro-4 "-butyl-p-terphenyl 4,2" -difluoro-4 "-pentyl-p-terphenyl 4-chloro-2" -fluoro- 4 "-ethyl p-terphenyl 4-chloro-2 "-fluoro-4" -propyl-p-terphenyl 4-chloro-2 "-fluoro-4" -butyl-p-terphenyl 4-chloro-2 "-fluoro-4 "-Pentyl-p-terphenyl 4-trifluoromethyl-2" -fluoro-4 "-ethyl-p-terphenyl 4-trifluoromethyl-2" -fluoro-4 "-propyl-p-terphenyl 4- Trifluoromethyl-2 "-fluoro-4" -butyl-p-terphenyl 4-trifluoromethyl-2 "-fluoro-4" -pentyl-p-terphenyl 4-trifluoromethoxy-2 "-fluoro-4 "-Ethyl-p-terphenyl 4-trifluoromethoxy-2" -fluoro-4 "-propyl-p-terphenyl 4-trifluoromethoxy-2" -f Oro-4 "
-Butyl-p-terphenyl 4-trifluoromethoxy-2 "-fluoro-4" -pentyl-p-terphenyl 4-difluoromethoxy-2 "-fluoro-4" -ethyl-p-terphenyl 4-difluoromethoxy -2 "-fluoro-4" -propyl-p-terphenyl 4-difluoromethoxy-2 "-fluoro-4" -butyl-p-terphenyl 4-difluoromethoxy-2 "-fluoro-4" -pentyl-p -Terphenyl 4- (2,2,2-trifluoroethoxy) -2 "-fluoro-4" -ethyl-p-terphenyl 4- (2,2,2-trifluoroethoxy) -2 "-fluoro- 4 "-propyl-p-terphenyl 4- (2,2,2-trifluoroethoxy) -2" -fluoro-4 "-butyl-p-terphenyl 4- (2 , 2-trifluoroethoxy) -2 "- fluoro-4 '- pentyl -p- terphenyl (Example 2) 3,4,5,2' - tetrafluoro -
Synthesis of 4 "-(3-butenyl) -p-terphenyl 30 g of 3,4,5,2" -tetrafluoro-4 "-bromo-p-terphenyl obtained in (1-a) and 1.5
g of dichloro [1,2-bis (diphenylphosphino)]
[Ethane] nickel (II) was dissolved in 150 ml of THF.
A THF solution of a Grignard reagent prepared from 1-bromo-3-butene was added dropwise thereto at room temperature under a nitrogen atmosphere. Add a small amount of water and dilute hydrochloric acid, extract with toluene,
After washing with water and then with a saturated saline solution, it was dehydrated and dried with anhydrous sodium sulfate. The crude product obtained by distilling off the solvent was purified by silica gel column chromatography (hexane), and further recrystallized from ethanol to give 3,4,4.
5,2 "-tetrafluoro-4"-(3-butenyl)-
16 g of white crystals of p-terphenyl were obtained.

Similarly, the following compounds can be obtained. 3,4,5,2 "-tetrafluoro-4"-(trans-3-pentenyl) -p-terphenyl 3,4,2 "-trifluoro-4"-(3-butenyl)
-P-terphenyl 3,4,2 "-trifluoro-4"-(trans-3-
Pentenyl) -p-terphenyl 4,2 "-difluoro-4"-(3-butenyl) -p-
Terphenyl 4,2 "-difluoro-4"-(trans-3-pentenyl) -p-terphenyl 3,5,2 "-trifluoro-4-chloro-4"-(3
-Butenyl) -p-terphenyl 3,5,2 "-trifluoro-4-chloro-4"-(trans-3-pentenyl) -p-terphenyl 3,2 "-difluoro-4-chloro-4" -(3-butenyl) -p-terphenyl 3,2 "-difluoro-4-chloro-4"-(trans-3-pentenyl) -p-terphenyl 3,5,2 "-trifluoro-4-tri Fluoromethoxy-4 "-(3-butenyl) -p-terphenyl 3,5,2" -trifluoro-4-trifluoromethoxy-4 "-(trans-3-pentenyl) -p-terphenyl 3,2 "-Difluoro-4-trifluoromethoxy-
4 "-(3-butenyl) -p-terphenyl 3,2" -difluoro-4-trifluoromethoxy-
4 "-(trans-3-pentenyl) -p-terphenyl 3,5,2" -trifluoro-4-trifluoromethyl-4 "-(3-butenyl) -p-terphenyl 3,5,2" -Trifluoro-4-trifluoromethyl-4 "-(trans-3-pentenyl) -p-terphenyl 3,2" -difluoro-4-trifluoromethyl-4 "
-(3-butenyl) -p-terphenyl 3,2 "-difluoro-4-trifluoromethyl-4"
-(Trans-3-pentenyl) -p-terphenyl 3,5,2 "-trifluoro-4-difluoromethoxy-4"-(3-butenyl) -p-terphenyl 3,5,2 "-trifluoro -4-Difluoromethoxy-4 "-(trans-3-pentenyl) -p-terphenyl 3,2" -difluoro-4-difluoromethoxy-4 "
-(3-butenyl) -p-terphenyl 3,2 "-difluoro-4-difluoromethoxy-4"
-(Trans-3-pentenyl) -p-terphenyl 3,5,2 "-trifluoro-4- (2,2,2-trifluoromethoxy) -4"-(3-butenyl) -p-terphenyl 3,5,2 "-trifluoro-4- (2,2,2-trifluoromethoxy) -4"-(trans-3-pentenyl) -p-terphenyl 3,2 "-difluoro-4- (2 , 2,2-trifluoromethoxy) -4 "-(3-butenyl) -p-terphenyl 3,2" -difluoro-4- (2,2,2-trifluoromethoxy) -4 "-(trans- 3-pentenyl)-
p-Terphenyl (Example 3) Preparation of liquid crystal composition Liquid crystal composition (M) having a wide temperature range and low viscosity, and particularly suitable as a host liquid crystal for STN display and active matrix driving.

[0057]

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Was prepared. The dielectric anisotropy (Δε) of this composition at 20 ° C., the threshold voltage (Vth) of a TN cell having a cell thickness of 6.0 μm prepared using the composition, and the refractive index anisotropy (Δn) at that time are as follows. It was as follows.

Threshold voltage (Vth): 2.14 V Dielectric anisotropy (Δε): 4.8 Refractive index anisotropy (Δn): 0.090 Next, 70% of the host liquid crystal (M) is used in the present invention. (No.1)

[0060]

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A liquid crystal composition (M-1) consisting of 30% was prepared. The physical properties and electro-optical properties of this composition were as follows. Threshold voltage (Vth): 1.53 V Dielectric anisotropy (Δε): 7.9 Refractive index anisotropy (Δn): 0.122 Thus, by mixing the compound of (No. 1),
The dielectric anisotropy of the composition was increased, and as a result, the threshold voltage could be significantly reduced. In addition, the refractive index anisotropy is greatly increased, and the cell thickness can be further reduced. Further, this composition did not cause precipitation of crystals or phase separation even when left at -20 ° C for 1 week. (Comparative Example) In Example 3, a compound represented by the general formula (II) (A) was used instead of the compound (No. 1).

[0062]

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Was added to (M) in the same amount (30%) to prepare a liquid crystal composition (MA). The characteristic values of this composition were as follows. Threshold voltage (Vth): 1.90 V Dielectric anisotropy (Δε): 7.7 Refractive index anisotropy (Δn): 0.133 Thus, regarding the effect of increasing the refractive index anisotropy, (N
Although superior to the compound of o.1), the effects of increasing the dielectric anisotropy and reducing the threshold voltage were not as high as (M-1). Furthermore, when left at −20 ° C. for one week, precipitation of crystals was observed, and the compatibility was inferior to the compound of (No. 1).

[0064]

According to the present invention, general formula (I) is provided.
The fluoroterphenyl derivative of can be easily produced industrially as shown in Examples, and is a colorless light,
Extremely stable chemically to heat, water, etc. Excellent compatibility with conventional liquid crystal compositions. Moreover, the refractive index anisotropy is extremely large and the dielectric anisotropy is also large. Therefore, it is useful as a constituent material of a liquid crystal display composition requiring a wide temperature range, excellent high-speed response, and low-voltage driving.

Claims (6)

[Claims] 1. A compound of the general formula (I) (Wherein, R represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 3 to 10 carbon atoms, and Z represents a fluorine atom, a chlorine atom, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group or A fluoroterphenyl derivative represented by a 2,2,2-trifluoroethoxy group, and X ¹ and X ² each independently represent a hydrogen atom or a fluorine atom. 2. The fluoroterphenyl derivative according to claim 1, wherein in formula (I), Z is a fluorine atom or a trifluoromethoxy group. 3. The method according to claim 1, wherein, in the general formula (I), R represents a linear alkyl group having 1 to 7 carbon atoms or a linear alkenyl group having 4 to 7 carbon atoms. Fluoroterphenyl derivatives. 4. The fluoroterphenyl derivative according to claim 1, wherein in formula (I), at least one of X ¹ and X ² represents a fluorine atom. 5. The fluoroterphenyl derivative according to claim 4, wherein in formula (I), X ¹ and X ² both represent a fluorine atom. 6. A liquid crystal composition containing the compound represented by the general formula (I) according to claim 1.