JP2009149630A - Fluorine-containing liquid crystal compound, liquid crystal composition comprising the same, and liquid crystal electrooptical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal compound having a low rotational viscosity (γ1), and a wide liquid crystal temperature range, to provide a liquid crystal composition using the compound, and to provide a liquid crystal electrooptical device using the composition. <P>SOLUTION: The fluorine-containing liquid crystal compound is represented by following formula (1): CH<SB>2</SB>=CH-(Cy)<SB>m</SB>-CF<SB>2</SB>CF<SB>2</SB>-Cy-(A)<SB>n</SB>-R (1) äwherein, symbols in formula (1) represent each following meaning; R is a hydrogen atom or a 1C-10C monovalent aliphatic hydrocarbon group, with the proviso that one or more hydrogen atoms in the aliphatic hydrocarbon group may be substituted with a halogen atom, and an oxygen atom may be inserted into at least either of the bond between carbon-carbon atoms in the aliphatic hydrocarbon group and the bond terminal of the aliphatic hydrocarbon group; and when n is 1, and A is a 1,4-phenylene group in which one or more hydrogen atoms in the group may be substituted with a fluorine atom, R is a hydrogen atom, a 1-10C monovalent aliphatic hydrocarbon group, a halogen atom, or a cyano group; A is a trans-1,4-cyclohexylene group, or a 1,4-phenylene group in which one or more hydrogen atoms in the group may be substituted with a fluorine atom; Cy is a trans-1,4-cyclohexylene group; m is 1 or 2; and n is 0 or 1, with the proviso that m+n means 1 or 2}. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluorine-containing compound having liquid crystallinity, a liquid crystal composition containing the same, and a liquid crystal electro-optical element.

  Liquid crystal electro-optical elements include portable devices such as mobile phones and PDAs, display devices for office automation equipment such as copiers and personal computer monitors, display devices for home appliances such as liquid crystal televisions, watches, calculators, measuring instruments, and automobiles. It is used for applications such as instruments and cameras, and various performances such as a wide operating temperature range, a low operating voltage, high-speed response, and chemical stability are required.

  A material exhibiting a liquid crystal phase is used for such a liquid crystal electro-optical element, but at present, not all of these performances are satisfied by a single compound, and one or more performances are excellent. A plurality of liquid crystal compounds and non-liquid crystal compounds are mixed to satisfy the required performance as a liquid crystal composition.

  Among various performances required for compounds used in liquid crystal materials in the field of liquid crystal electro-optic elements, it has excellent compatibility with other liquid crystal compounds or non-liquid crystal compounds, is chemically stable, and When used in a liquid crystal electro-optical element, it is an important problem to provide a compound having excellent high-speed response in a wide temperature range and capable of being driven at a low voltage.

In recent years, in order to realize a higher-definition moving image display, it is a particularly important issue to provide a liquid crystal material that is particularly excellent in high-speed response. In order to increase the response speed, it is necessary to physically reduce the rotational viscosity (γ1) or increase the elastic constant, but if the elastic constant (K) is increased, the threshold voltage increases. Lowering the viscosity (γ1) is an effective means.
However, a liquid crystal compound having a low rotational viscosity generally has a low liquid crystal clearing point (Tc), and the blending of such a liquid crystal compound has a concern of lowering the liquid crystal temperature range of the liquid crystal material. Therefore, the rotational viscosity (γ1) is low. There is also a need for a liquid crystal compound having a high liquid crystal clearing point (Tc) and a wide liquid crystal temperature range.

As the literature described liquid crystal compound having a CF ₂ CF ₂ linking group, for example, US Pat.

JP 2000-192041 A JP 05-331084 A

However, Patent Document 1 and Patent Document 2 do not show specific examples of liquid crystal compounds having a CF ₂ CF ₂ linking group and a terminal vinyl group, and the rotational viscosity, liquid crystal temperature range, compatibility, etc. are considered. Not.
Note that “the liquid crystal clearing point (Tc) is high” and “the liquid crystal temperature range is wide” are not synonymous. For example, if the upper limit temperature (Tc) of the liquid crystal phase is high and the lower limit temperature of the liquid crystal phase is high, the liquid crystal temperature range is narrowed.

Therefore, an object of the present invention is to provide a liquid crystal compound having a low rotational viscosity (γ1) and a wide liquid crystal temperature range.
Another object of the present invention is to provide a liquid crystal composition that is excellent in responsiveness, has a wide operating temperature range, and can provide a highly reliable liquid crystal electro-optic element.
Another object of the present invention is to provide a liquid crystal electro-optical element that has excellent responsiveness, a wide operating temperature range, and high reliability.

  As a result of intensive studies to solve the above problems, the present inventors have found that the fluorine-containing liquid crystal compound represented by the following formula (1) has a low rotational viscosity (γ1) and a wide liquid crystal temperature range, It has been found useful as a material, and the present invention has been completed.

That is, the present invention provides a fluorine-containing liquid crystal compound represented by the following formula (1).
_{CH 2 = CH- (Cy) m} -CF 2 CF 2 -Cy- (A) n -R (1)
However, the symbol in Formula (1) shows the following meanings.
A: a trans-1,4-cyclohexylene group, or a 1,4-phenylene group in which one or more hydrogen atoms in the group may be substituted with a fluorine atom.
Cy: trans-1,4-cyclohexylene group.
m: 1 or 2.
n: 0 or 1.
However, m + n means 1 or 2.
R: When n is 0 or n is 1 and A is a trans-1,4-cyclohexylene group, it is a hydrogen atom or a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms (provided that One or more hydrogen atoms in the aliphatic hydrocarbon group may be substituted with a halogen atom, and among the carbon-carbon atoms in the aliphatic hydrocarbon group and the bonding terminal of the aliphatic hydrocarbon group An oxygen atom may be inserted into at least one), n is 1, and A is a 1,4-phenylene group in which one or more hydrogen atoms in the group may be substituted with a fluorine atom Is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, a halogen atom or a cyano group.

  The fluorine-containing liquid crystal compound is preferably a fluorine atom when R in the formula (1) is a linear alkyl group having 1 to 5 carbon atoms or when R is a halogen atom.

  In the fluorine-containing liquid crystal compound, m in the formula (1) is preferably 1 and n is preferably 0.

  The present invention also provides a liquid crystal composition containing 1% by mass or more of the fluorine-containing liquid crystal compound represented by the formula (1) and 60% by mass or more of another liquid crystal compound.

  The liquid crystal composition preferably contains 1 to 30% by mass of the fluorine-containing liquid crystal compound and 60% by mass or more of the other liquid crystal compound.

  The present invention also provides a liquid crystal electro-optical element in which the liquid crystal composition is sandwiched between substrates with electrodes.

The fluorine-containing liquid crystal compound of the present invention has a low rotational viscosity (γ1) necessary for high-speed response. Moreover, it has a wide liquid crystal temperature range. Furthermore, it is excellent in compatibility with other liquid crystal compounds or non-liquid crystal compounds and is chemically stable.
Further, by using the liquid crystal composition of the present invention, a liquid crystal electro-optical element having excellent responsiveness, a wide operating temperature range, and high reliability can be obtained.
In addition, the liquid crystal electro-optical element of the present invention has excellent responsiveness, a wide operating temperature range, and high reliability.

The present invention will be described in more detail below.
In this specification, the fluorine-containing liquid crystal compound represented by the formula (1) is referred to as the compound (1), and the compounds represented by other formulas are also described in the same manner.

The compound (1) of the present invention has a structure in which two trans-1,4-cyclohexylene groups are bonded by a CF ₂ CF ₂ linking group and a vinyl group directly connected to the trans-1,4-cyclohexylene group at the terminal. It is a compound having liquid crystal properties.

_{CH 2 = CH- (Cy) m} -CF 2 CF 2 -Cy- (A) n -R (1)

In the formula (1), R is a hydrogen atom or a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms. However, one or more hydrogen atoms in the aliphatic hydrocarbon group may be substituted with a halogen atom, and between carbon-carbon atoms in the aliphatic hydrocarbon group and the bonding terminal of the aliphatic hydrocarbon group Of these, at least one of them may have an etheric oxygen atom inserted therein. When n is 1 and A is a 1,4-phenylene group in which one or more hydrogen atoms in the group may be substituted with a fluorine atom, R is a hydrogen atom, having 1 to 10 carbon atoms. A monovalent aliphatic hydrocarbon group, a halogen atom or a cyano group;
In the aliphatic hydrocarbon group, substitution with a halogen atom and insertion of an etheric oxygen atom may be performed simultaneously on the same aliphatic hydrocarbon group.

  As the halogen atom in R, a fluorine atom and a chlorine atom are preferable, and a fluorine atom is more preferable.

Examples of the monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms in R include an alkyl group, an alkenyl group, and an alkynyl group. The monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferably linear.
In addition, examples of the group in which one or more hydrogen atoms in these groups are substituted with a halogen atom include a fluoroalkyl group and a chloroalkyl group.
Further, examples of the group in which an etheric oxygen atom is inserted between carbon-carbon atoms in these groups include an alkoxyalkyl group, an alkoxy group in which an etheric oxygen atom is inserted at the bond terminal of the group, a fluoroalkoxy group, and the like. Can be mentioned.

  As R, a halogen atom and a C1-C10 alkyl group are preferable, and a fluorine atom and a linear C1-C5 alkyl group are more preferable.

In the formula (1), A represents a trans-1,4-cyclohexylene group or a 1,4-phenylene group in which one or more hydrogen atoms in the group may be substituted with a fluorine atom.
The positions of the 1st and 4th positions of the cyclic group are the 4th position closer to R in the formula (1).

The 1,4-phenylene group in which one or more hydrogen atoms in the group in A may be substituted with a fluorine atom is preferably a 1,4-phenylene group substituted with one or two fluorine atoms.
Examples of the 1,4-phenylene group in which one or two hydrogen atoms in the phenylene group are substituted by fluorine atoms include, for example, 2-fluoro-1,4-phenylene group, 3-fluoro-1, Examples include 4-phenylene group, 2,3-difluoro-1,4-phenylene group, 3,5-difluoro-1,4-phenylene group, 2,6-difluoro-1,4-phenylene group. Among these, a 3,5-difluoro-1,4-phenylene group is more preferable.

  A is preferably a trans-1,4-cyclohexylene group and a 1,4-phenylene group in which one or two hydrogen atoms in the group may be substituted with a fluorine atom.

In the formula (1), m is 1 or 2, and n is 0 or 1. However, m + n is 1 or 2. It is preferable that m is 1 and n is 0 because rotational viscosity becomes low.
Further, when n is 0, it means that Cy and R at both ends of (A) _n in formula (1) are directly bonded.

Specific examples of the compound (1) include those represented by the following formula.
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-CH 3
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-C 2 H 5
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-C 3 H 7
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-C 5 H 10
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Ph-CH 3
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Ph-C 2 H 5
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Ph-C 3 H 7
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Ph-C 5 H 10
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Ph-F
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Ph (3F) -F
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Ph (2F, 3F) -F
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Ph (3F, 5F) -F
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Cy-CH 3
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Cy-C 2 H 5
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Cy-C 3 H 7
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Cy-C 5 H 10
_{CH 2 = CH-Cy-Cy} -CF 2 CF 2 -Cy-CH 3
_{CH 2 = CH-Cy-Cy} -CF 2 CF 2 -Cy-C 2 H 5
_{CH 2 = CH-Cy-Cy} -CF 2 CF 2 -Cy-C 3 H 7
_{CH 2 = CH-Cy-Cy} -CF 2 CF 2 -Cy-C 5 H 10

However, the symbols in the above formulas have the following meanings.
Cy: trans-1,4-cyclohexylene group Ph: 1,4-phenylene group Ph (3F): 3-fluoro-1,4-phenylene group Ph (2F, 3F): 2,3-difluoro-1,4 -Phenylene group Ph (3F, 5F): 3,5-difluoro-1,4-phenylene group

  The compound (1) of the present invention can be synthesized, for example, by a so-called wittig reaction in which a compound (2) of the following formula is reacted with methyltriphenylphosphonium halide in the presence of a base in a solution.

OHC- (Cy) _m -CF ₂ CF ₂ -Cy- (A) _n -R (2)
^{_{↓ CH 3 P + Ph 3 X}} - base _{CH 2 = CH- (Cy) m} -CF 2 CF 2 -Cy- (A) n -R (1)

  However, the symbols in formula (1) and formula (2) have the same meaning as described above.

Among the compounds represented by the formula (2), for example, R = C ₃ H ₇ , m = 1, n = 0 compound (2A) can be synthesized by the following route (J. Fluorine Chem., 112, (2001), 69-72.). Other bicyclic compounds represented by the formula (2) can be synthesized in the same manner.

  Of the compounds represented by the formula (2), the compound (2B) in which m = 1, n = 1, and R ≠ CN can be synthesized by the following route. That is, after adding an aryl Grignard reagent, an aryl lithium reagent, a cyclohexyl Grignard reagent or a cyclohexyl lithium reagent to the compound (6A), the produced alcohol form (11) is subjected to a dehydration step, a hydrogenation step, and a deprotection step, After conversion to the ketone body (14), the compound (2B) can be synthesized in the same manner as the bicyclic compound.

The symbols in the above reaction formula have the following meanings.
A: The same meaning as A in Formula (1) is shown.
M: MgCl, MgBr, MgI or Li
R: The same meaning as R in Formula (1) is shown. However, the cyano group is excluded.

  The compound (14) in the synthesis route of the compound (2B) can also be synthesized by the following route using a 1,1,2-trifluoro-2- (trans-4-substituted cyclohexyl) ethylene compound as a raw material. That is, the following compound (23) was reacted with hydrogen fluoride-pyridine (HF-Py) and compound (9) in the presence of N-iodosuccinimide (NIS) to synthesize compound (24). The compound (25) is added to and converted into the alcohol form (26), and then subjected to a dehydration step, a hydrogenation step, and a deprotection step to synthesize a compound (14) that is a ketone body. The synthesis method of the raw material compound (23) is described in, for example, Japanese Patent Application Laid-Open No. 2000-080366, and can be described in the present specification with reference to the description of the publication.

  Of the compounds represented by the formula (2), the compound (2C) having m = 1, n = 1, and R = CN can be synthesized, for example, by the route of the following formula. That is, the compound (13A) in which R = Cl is synthesized, a CN group is introduced by a substitution reaction, and then the compound (2C) can be converted.

  Of the compounds represented by the formula (2), the compound (2D) with m = 2 and n = 0 can be synthesized by the route of the following formula. That is, after adding the compound (17) to the compound (9) and converting it to the alcohol (18), it is subjected to a dehydration step, a hydrogenation step, and a deprotection step, and then converted to a ketone body (21). Compound (2D) can be synthesized in the same manner as the bicyclic compound.

The symbols in the above reaction formula have the following meanings.
M: Shows the same meaning as above.
R: The same meaning as R in Formula (1) is shown.

  The synthesis of the fluorine-containing compound in this reaction is preferably carried out in a solvent. Solvents include aromatic hydrocarbon solvents such as benzene, toluene, xylene and ethylbenzene, aliphatic hydrocarbon solvents such as pentane, hexane, heptane and octane; tetrahydrofuran, diethyl ether, dibutyl ether, t-butyl methyl ether, dimethoxy Ether solvents such as ethane; petroleum ethers or a suitable mixed solvent of the above solvents can be used. Among these, ether solvents such as tetrahydrofuran, aromatic hydrocarbon solvents such as toluene, and mixed solvents of ether solvents and aliphatic hydrocarbon solvents are preferable.

  The amount of the solvent is preferably 0.1 to 100 times, more preferably 0.5 to 20 times the amount of 1 mol of the compound (2). For example, when the compound (2) is 1 mmol, the solvent is preferably used in an amount of 0.1 to 100 ml, more preferably 0.5 to 20 ml.

  The reaction temperature is preferably −100 to + 120 ° C., more preferably −30 to + 70 ° C.

  The reaction time is preferably 0.5 to 48 hours, more preferably 0.5 to 8 hours.

  Examples of the base include alkali metal alkoxides such as sodium butoxide, potassium butoxide, sodium ethoxide and sodium methoxide; alkyllithiums such as n-butyllithium and methyllithium; alkali metal hydrides such as sodium hydride And the like. These may be used alone or in combination of two or more. Among these, alkali metal alkoxides and alkyl lithiums are preferable.

  As a usage-amount of a base, 0.9-5 equivalent is preferable with respect to methyltriphenylphosphonium halide, and 1-2 equivalent is more preferable.

Examples of the methyltriphenylphosphonium halide include methyltriphenylphosphonium chloride, methyltriphenylphosphonium bromide, and methyltriphenylphosphonium iodide. These may be used alone or in combination of two or more.
The amount of methyltriphenylphosphonium halide used is preferably 1 to 5 equivalents and more preferably 1 to 2 equivalents of compound (2).

The above-described fluorine-containing liquid crystal compound of the present invention is not usually used alone for a liquid crystal electro-optical element, but is a liquid crystal composition that is a mixture with other liquid crystal compounds, and the liquid crystal composition is a liquid crystal electro-optical device. Used for elements and the like. Since the fluorine-containing liquid crystal compound of the present invention used as a component of the liquid crystal composition has a low rotational viscosity (γ1), the composition of this fluorine-containing liquid crystal compound reduces the rotational viscosity (γ1) of the liquid crystal composition. As a result, the responsiveness of the liquid crystal electro-optical element using the composition can be improved. Moreover, since the fluorine-containing liquid crystal compound of the present invention has a wide liquid crystal temperature range, it can provide a liquid crystal composition that can be used in a wide temperature range.
Furthermore, since the fluorine-containing liquid crystal compound of the present invention is excellent in compatibility with other liquid crystal compounds or non-liquid crystal compounds and is chemically stable, there are restrictions on the types of other liquid crystal compounds used in combination. It can be applied to various liquid crystal compositions depending on the purpose.
In addition, since the liquid crystal clearing point (Tc) of the fluorine-containing liquid crystal compound of the present invention is relatively high, there is little decrease in the liquid crystal clearing point (Tc) of the liquid crystal composition by the combined use of the fluorine-containing liquid crystal compound of the present invention, or The liquid crystal clearing point (Tc) of the liquid crystal composition can be increased by the combined use of the fluorine-containing liquid crystal compound of the present invention.

  Although the use of the fluorine-containing liquid crystal compound of the present invention is not particularly limited, it is suitable for use as a component of a liquid crystal composition for a liquid crystal electro-optical element, particularly for a liquid crystal display element because of having the above-described excellent characteristics. It is particularly useful.

Next, the liquid crystal composition of the present invention will be described.
The liquid crystal composition of the present invention contains 1% by mass or more of the above-described fluorinated liquid crystal compound of the present invention and 60% by mass or more of the other liquid crystal compound. Two or more other liquid crystal compounds may be contained. When the content of the above-mentioned fluorinated liquid crystal compound of the present invention in the liquid crystal composition of the present invention is less than the above range, it is difficult to sufficiently exhibit the characteristics of the fluorinated liquid crystal compound of the present invention.

The liquid crystal composition of the present invention may contain a non-liquid crystal compound in addition to these liquid crystal compounds.
Examples of the non-liquid crystal compound include chiral agents, dyes, stabilizers, and various functional compounds blended in other liquid crystal compositions. Some chiral agents and pigments have liquid crystallinity, and in the present invention, such functional compounds having liquid crystallinity are classified as liquid crystals.

Liquid crystal compositions for liquid crystal electro-optical elements (particularly for liquid crystal display elements) are usually composed of a mixture of various liquid crystal compounds. The liquid crystal composition for this use often contains 5 or more (especially 10 or more) liquid crystal compounds. The content of one kind of liquid crystal compound with respect to all liquid crystal compounds in the liquid crystal composition rarely exceeds 50% by mass, and is usually 30% by mass or less. Therefore, each liquid crystal compound in the liquid crystal composition is often in the range of 1 to 25% by mass. Certain liquid crystal compounds contained in the liquid crystal composition may be less than 1% by mass (usually 0.1% by mass or more). Even such a small amount is contained in the liquid crystal composition. Has technical significance. In addition, the liquid crystal composition for this use often contains a chiral agent, but the content is usually 10% by mass or less, particularly 5% by mass or less, based on the total liquid crystal compounds.
The liquid crystal compound in the present invention is not limited to a compound exhibiting liquid crystallinity at room temperature as a single compound. When the liquid crystal composition is used for a certain application, the liquid crystal composition in the liquid crystal composition at the use temperature is used. Any compound may be used as long as it exhibits properties. For example, the single compound may be a solid at room temperature or a compound exhibiting liquid crystallinity at the above use temperature when dissolved in a liquid crystal composition.

In consideration of the above situation, the liquid crystal composition of the present invention preferably contains 1 to 30% by mass of the above-described fluorine-containing liquid crystal compound of the present invention and 60% by mass or more of the other liquid crystal compound, It is more preferable to contain 1 to 25% by mass of the above-described fluorine-containing liquid crystal compound of the present invention and 70% by mass or more of other liquid crystal compounds. The content of other liquid crystal compounds is preferably 99% by mass or less.
In addition, the total amount of the fluorine-containing liquid crystal compound of the present invention and other liquid crystal compounds is preferably 90% by mass or more, particularly 95% by mass or more based on the liquid crystal composition.
In addition, when the liquid crystal composition of the present invention contains two or more kinds of the above-mentioned fluorine-containing liquid crystal compounds of the present invention, the ratio of the above-mentioned fluorine-containing liquid crystal compounds of the present invention is the ratio of the two or more kinds of liquid crystal compounds of the present invention. Represents the total amount.

The kind of other liquid crystal compound in the liquid crystal composition of the present invention is not limited. A liquid crystal composition can be constituted with the liquid crystal compound of the present invention by selecting any kind of liquid crystal compound according to the purpose. Moreover, functional compounds, such as a chiral agent, can be mix | blended if necessary. Moreover, the liquid crystal compound of the present invention can be blended with an existing liquid crystal composition (for example, a commercially available liquid crystal composition) to obtain the liquid crystal composition of the present invention. Although the manufacturing method of the liquid-crystal composition of this invention is not specifically limited, For example, it can obtain by mixing each component mentioned above with a stirrer etc.
The other liquid crystal compound constituting the liquid crystal composition of the present invention is preferably selected from the following liquid crystal compounds known or known as liquid crystal compounds. However, other liquid crystal compounds in the liquid crystal composition of the present invention are not limited to these.

R ² -A ² -A ³ -R ³
R ² -A ² -C≡C-A ³ -R ^{3
R 2 -A 2 -COO-A 3} -R 3
_{^{R 2 -A 2 -CH 2 CH 2}} -A 3 -R 3
^{R 2 -A 2 -CH = CH-} A 3 -R 3
^{R 2 -A 2 -CF = CF-} A 3 -R 3
_{^{R 2 -A 2 -CF 2 O-}} A 3 -R 3
_{^{R 2 -A 2 -CF 2 CF 2}} -A 3 -R 3
R ² -A ² -A ³ -A ⁴ -R ³
R ² -A ² -A ³ -C≡C-A ⁴ -R ^{3
R 2 -A 2 -A 3 -COO-} A 4 -R 3
_{^{R 2 -A 2 -A 3 -CH 2}} CH 2 -A 4 -R 3
^{R 2 -A 2 -A 3 -CH =} CH-A 4 -R 3
^{R 2 -A 2 -A 3 -CF =} CF-A 4 -R 3
_{^{R 2 -A 2 -A 3 -CF 2}} O-A 4 -R 3
_{^{R 2 -A 2 -A 3 -CF 2}} CF 2 -A 4 -R 3
R ² -A ² -A ³ -A ⁴ -A ⁵ -R ³
R ² -A ² -A ³ -C≡C-A ⁴ -A ⁵ -R ^{3
_{R 2 -A 2 -CH 2 CH 2}} -A 3 -C≡C-A 4 -R 3
R ² —A ² —CH ₂ CH ₂ —A ³ —C≡C—A ⁴ —A ⁵ —R ^{3
R 2 -A 2 -COO-A 3} -A 4 -R 3
^{R 2 -A 2 -COO-A 3} -COO-A 4 -R 3

In the above formula, R ² and R ³ represent an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a halogen atom or a cyano group. R ² and R ³ may be the same or different. A ² , A ³ , A ⁴ and A ⁵ are each independently a trans-1,4-cyclohexylene group, or one or more hydrogen atoms in the group may be substituted with a fluorine atom 1 , 4-phenylene group.

These compounds are exemplary, and the hydrogen atom present in the ring structure or terminal group in the compound may be substituted with a halogen atom, a cyano group, a methyl group, or the like. Further, the ring groups A ^{2 to} A ⁵ may be substituted with a pyrimidine ring or a dioxane ring. Furthermore, the linking group between the Hajime Tamaki and the ring _{group, -CH 2 O -, - CH} = CH -, - N = N -, - CH = N -, - COOCCH 2 -, - OCOCH 2 - or - COCH ₂ - may be one that is changed or the like. These can be selected according to the desired performance.

Next, the liquid crystal electro-optical element of the present invention will be described.
The present invention provides a liquid crystal electro-optical element that is suitably used as a constituent material of a liquid crystal phase.
The liquid crystal electro-optical element of the present invention is a liquid crystal electro-optical element in which the liquid crystal composition of the present invention described above is sandwiched between substrates with electrodes.
The liquid crystal electro-optical element of the present invention is not particularly limited except that the liquid crystal composition of the present invention is used, and the configuration of a normal liquid crystal electro-optical element can be adopted.
As the liquid crystal electro-optical element of the present invention, for example, an electric circuit constituted by sandwiching a liquid crystal phase formed by injecting the liquid crystal composition of the present invention into a liquid crystal cell between two substrates provided with electrodes. A liquid crystal electro-optical element having an optical element part is exemplified. Examples of the liquid crystal electro-optical element include those driven in various modes such as a twisted nematic method, a guest host method, a dynamic scattering method, a phase change method, a DAP method, a dual frequency driving method, and a ferroelectric liquid crystal display method. .

A typical liquid crystal electro-optic element includes a twisted nematic (TN) type liquid crystal display element. In this twisted nematic (TN) type liquid crystal display element, first, an undercoat layer such as SiO ₂ or Al ₂ O ₃ or a color filter layer is formed on a substrate such as plastic or glass as necessary, and then In ₂ O _A film made of _3- SnO ₂ (ITO), SnO ₂ or the like is formed, and an electrode having a required pattern is formed by photolithography. Next, if necessary, an overcoat layer of polyimide, polyamide, SiO ₂ , Al ₂ O ₃ or the like is formed and subjected to orientation treatment. A sealing material is printed on this, it arrange | positions so that an electrode surface may mutually oppose, a periphery is sealed, a sealing material is hardened, and an empty cell is formed.

  Furthermore, the liquid crystal composition of the present invention is injected into the empty cell, and the injection port is sealed with a sealant to form a liquid crystal cell. If necessary, this liquid crystal cell is laminated with a polarizing plate, a color polarizing plate, a light source, a color filter, a transflective plate, a reflecting plate, a light guide plate, an ultraviolet cut filter, etc., printing characters, figures, etc. Thus, a liquid crystal electro-optical element can be obtained.

  The above description describes the basic configuration and manufacturing method of the liquid crystal electro-optical element, and other configurations can be employed. For example, a substrate using a two-layer electrode, a two-layer liquid crystal cell having a two-layer liquid crystal layer, a substrate using a reflective electrode, an active matrix device using an active matrix substrate having an active element such as a TFT or MIM, etc. Various configurations can be employed.

  Furthermore, the liquid crystal composition of the present invention has a mode other than the TN type, that is, a super twist nematic (STN) type liquid crystal electro-optical element having a high twist angle, or a guest-host (GH) type using a polychromatic dye. A liquid crystal electro-optical element, an in-plane switching (IPS) liquid crystal electro-optical element that drives liquid crystal molecules parallel to the substrate by a horizontal electric field, a VA liquid crystal electro-optical element that vertically aligns liquid crystal molecules with respect to the substrate, It can be used in various ways such as a ferroelectric liquid crystal electro-optical element. Further, it can be used not only in a method of electrically writing but also in a method of writing by heat.

  The above-described liquid crystal electro-optical element of the present invention has excellent responsiveness, a wide operating temperature range, and high reliability.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the examples shown below are intended to illustrate the present invention, and the present invention is not limited thereto.
A liquid crystal composition “ZLI-1565” manufactured by Merck was used as the base liquid crystal. “ZLI-1565” is a liquid crystal composition widely known as a standard liquid crystal, and is presumed to be a liquid crystal composition containing six types of known or known liquid crystal compounds represented by the above chemical formula. According to the literature, the physical properties of “ZLI-1565” are as follows.
TC _{→ N} <-40 ° C
_{TN → I} = 85 ℃
Δχ = 6.3 × 10 ⁻⁸ cm ³ g ⁻¹
K ₂₂ = 6.9 × 10 ⁻⁷ dyn

  Example 1 Synthesis of 1- (trans-4-ethenylcyclohexyl) -2- (trans-4-propylcyclohexyl) 1,1,2,2, -tetrafluoroethane (1A)

  13.2 g of methyltriphenylphosphonium bromide was dispersed in 40 ml of tetrahydrofuran (THF) and cooled to -10 ° C. While maintaining the internal temperature, 4.2 g of potassium tert-butoxide was added. After stirring for 1 hour while maintaining the internal temperature, a solution of 9 g of the following compound (2A) in 27 ml of THF was added dropwise. After stirring for 1.5 hours while gradually raising the internal temperature to room temperature, water was added to stop the reaction. After extraction with methyl t-butyl ether and evaporation of the solvent under reduced pressure, hexane was added, and the mixture was vigorously stirred under ice-cooling and filtered. The filtrate was evaporated under reduced pressure, and purified by column chromatography and recrystallization to obtain 3.8 g of the following compound (1A) as a colorless solid.

The ¹⁹ F-NMR and GC-MS data of the obtained compound (1A) are shown.
¹⁹ F-NMR (CDCl ₃ , CFCl ₃ ): δ-116.8 (m, 4F)
GC-MS M + 334, 159, 131, 123, 109, 91, 81, 67, 65

_{OHC-Cy-CF 2 CF 2} -Cy-C 3 H 7 (2A)
↓ CH ₃ P ⁺ Ph ₃ Br ⁻ , t-BuOK
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-C 3 H 7 (1A)

  In the above formula, compound (2A) was synthesized according to the synthesis method described above (see J. Fluorine Chem., 112, (2001), 69-72).

(Example 2 and Comparative Examples 1 and 2) Measurement of liquid crystal temperature range Measurement of the liquid crystal temperature range and identification of the liquid crystal phase of the compound (1A), the following compound (C1) and the following compound (C2) by the following method Went.
A sample was placed on a hot plate of a melting point measuring apparatus equipped with a polarizing microscope, heated at 1 ° C./min, and the phase change was observed.
Using a differential scanning calorimeter (DSC 6220, manufactured by SII Nanotechnology), the temperature was raised at 1 ° C./min to measure the phase change. The results are shown in Table 1.
The “liquid crystal temperature range” is a general expression of the N phase temperature range and the liquid crystal phase temperature range in Table 1.

_{CH 2 = CH-Cy-Cy} -C 3 H 7 (C1)
_{C 3 H 7 -Cy-CF 2} CF 2 -Cy-C 3 H 7 (C2)

  Compound (C1) was synthesized by the following synthesis route.

  The compound (C2) was synthesized by the following synthesis route (see J. Am. Chem. Soc., 123, (2001), 5414-5417).

  In Table 1, C represents a crystalline phase, Sm represents a smectic phase, N represents a nematic phase, and I represents an isotropic phase. In the “phase change” column, for example, “Sm 62 N” indicates a change from a smectic phase to a nematic phase at 62 ° C. as a boundary.

  As apparent from the results shown in Table 1, it was found that the compound (1A) of the present invention has the widest liquid crystal phase temperature range and nematic phase temperature range.

(Example 3 and Comparative Examples 3 and 4) Compatibility observation The amount of the compound (1A) of the present invention as shown in the following table was added to a liquid crystal composition “ZLI-1565” manufactured by Merck & Co., and dissolved, then at 0 ° C. saved. After 72 hours, the state of the composition was visually observed.
The same operation was performed on the compounds (C1) and (C2).
The case where no solid was precipitated was indicated as “◯”, and the case where solid was observed as “x”. The results are shown in the table below.

  As is clear from the results shown in Table 2, it was found that the compound (1A) of the present invention showed much better compatibility than the compound (C2).

Example 4
A liquid crystal composition was prepared by mixing 80 mol% (77% by mass) of a liquid crystal composition “ZLI-1565” manufactured by Merck Co., Ltd. and 20 mol% (23% by mass) of the compound (1A) of the present invention. This liquid crystal composition is referred to as a liquid crystal composition A.

(Comparative Example 5)
Merck's liquid crystal composition “ZLI-1565” 80 mol% (82 mass%) and the compound (C1) 20 mol% (18 mass%) used for the purpose of lowering viscosity in the past were mixed. A liquid crystal composition was prepared. This liquid crystal composition is referred to as a liquid crystal composition B.

(Comparative Example 6)
The liquid crystal composition “ZLI-1565” manufactured by Merck & Co., Inc. was mixed at a ratio of 92.5 mol% (90.7 mass%) and 7.5 mol% (9.3 mass%) of the compound (C2). I adjusted things. This liquid crystal composition is referred to as a liquid crystal composition C.

  With respect to the obtained liquid crystal compositions A to C, the liquid crystal clearing point (hereinafter also referred to as “Tc”) and rotational viscosity (hereinafter also referred to as “γ1”) were measured by the following methods.

Measurement of liquid crystal clearing point (Tc) A sample was placed on a hot plate of a melting point measurement apparatus equipped with a polarizing microscope, heated at 1 ° C./min, phase change was observed, and Tc was determined.

Measurement of Rotational Viscosity (γ1) The measurement was performed in Molecular Crystals and Liquid Crystals and Liquid Crystals, Vol. 259, 37 (1995).
Specifically, each liquid crystal composition was put in a TN cell having a cell gap of 8 μm, and γ1 at −20 ° C., 0 ° C., 20 ° C., 40 ° C., 60 ° C. (in Comparative Example 5 up to 40 ° C.) was measured. Γ1 at 0.85 Tc was calculated from the correlation between temperature and γ1. However, 0.85 Tc is a temperature (K) obtained by multiplying Tc (converted to absolute temperature (K)) of each liquid crystal composition by 0.85.

  The measurement results of the liquid crystal clearing point and rotational viscosity of the liquid crystal compositions A to C are shown in Table 3 below.

  As is apparent from the results shown in Table 3, the liquid crystal composition containing the compound (1A) of the present invention of Example 4 has a low rotational viscosity (γ1), and the compound (C2 of Comparative Example 6). The liquid crystal clearing point (Tc) equivalent to the liquid crystal composition containing

  As described above, it has been clarified that the compound of the present invention has good compatibility and can adjust a composition having both a high liquid crystal clearing point (Tc) and a low rotational viscosity (γ1).

(Example 5) 1- (4- (4-vinylcyclohexyl) -2- (4- (trans-4-propylcyclohexyl) -trans-cyclohexyl) -1,1,2,2-tetrafluoroethane (1B) Of methyltriphenylphosphonium bromide was dispersed in 40 ml of THF and cooled to −10 ° C. 4 g of potassium tert-butoxide was added while maintaining the internal temperature. 11 g of THF 66 ml solution was added dropwise, stirred for 1 hour while maintaining the internal temperature, water was added to stop the reaction, extraction with methyl-t-butyl ether was performed, the solvent was distilled off under reduced pressure, and hexane was added. The mixture was vigorously stirred under ice-cooling and filtered, and the filtrate was distilled off under reduced pressure, and purified by column chromatography and recrystallization to obtain (1B) as a white solid. It was obtained 6g.

¹⁹ F-NMR and GC-MS data of the obtained compound (1B) are shown.
¹⁹ F-NMR (CDCl ₃ , CFCl ₃ ): δ-116.9 (m, 4F)
GC-MS M + 416, 388, 373, 345, 318, 292, 275, 247, 220, 205, 189, 159, 131, 125, 109, 95, 83, 69, 55, 41

_{OHC-Cy-CF 2 CF 2} -Cy-Cy-C 3 H 7 (2B)
↓ CH ₃ P ⁺ Ph ₃ Br ⁻ , t-BuOK
_{CH 2 = CH-Cy-CF} 2 CF 2 -Cy-Cy-C 3 H 7 (1B)

Example 6 Synthesis of 1- (4- (4-vinylcyclohexyl) -trans-cyclohexyl) -2- (trans-4-propylcyclohexyl) -1,1,2,2-tetrafluoroethane (1D)

  6.5 g of methyltriphenylphosphonium bromide was dispersed in 20 ml of THF and cooled to −10 ° C. While maintaining the internal temperature, 2.2 g of potassium tert-butoxide was added. After stirring for 1 minute while maintaining the internal temperature, a solution of 5 g of compound (2D) in 43 ml of THF was added dropwise. After stirring for 30 minutes while gradually raising the internal temperature to room temperature, water was added to stop the reaction. After extraction with methyl-t-butyl ether and evaporation of the solvent under reduced pressure, hexane was added, and the mixture was vigorously stirred under ice-cooling and filtered. The filtrate was distilled off under reduced pressure, and purified by column chromatography and recrystallization to obtain 2 g of (1D) as a white solid.

The 19F-NMR and GC-MS data of the obtained compound (1D) are shown.
¹⁹ F-NMR (CDCl ₃ , CFCl ₃ ): δ −117 (m, 4F)
GC-MS M + 416, 387, 359, 346, 332, 191, 149, 131, 121, 109, 95, 81, 67, 55, 41

_{OHC-Cy-Cy-CF 2} CF 2 -Cy-C 3 H 7 (2D)
↓ CH ₃ P ⁺ Ph ₃ Br ⁻ , t-BuOK
_{CH 2 = CH-Cy-Cy} -CF 2 CF 2 -Cy-C 3 H 7 (1D)

(Example 7)
A liquid crystal composition was prepared by mixing 90 mol% (86% by mass) of a liquid crystal composition “ZLI-1565” manufactured by Merck Co., Ltd. and 10 mol% (14% by mass) of the compound (1B) of the present invention. . This liquid crystal composition is referred to as a liquid crystal composition D.

(Example 8)
A liquid crystal composition was prepared by mixing 90 mol% (86 mass%) of the liquid crystal composition “ZLI-1565” manufactured by Merck Co., Ltd. and 10 mol% (14 mass%) of the compound (1D) of the present invention. . This liquid crystal composition is referred to as a liquid crystal composition E.

＊実施例７の液晶組成物Ｄの回転粘性（γ１）は、−２０℃、０℃、２０℃、３０℃で測定したγ１から外挿した値である。 Table 4 below shows the liquid crystal clearing point (Tc) and rotational viscosity (γ1) of the obtained liquid crystal compositions D and E measured by the same method as described above.

* The rotational viscosity (γ1) of the liquid crystal composition D of Example 7 is a value extrapolated from γ1 measured at −20 ° C., 0 ° C., 20 ° C., and 30 ° C.

Claims (6)

A fluorine-containing liquid crystal compound represented by the following formula (1).
_{CH 2 = CH- (Cy) m} -CF 2 CF 2 -Cy- (A) n -R (1)
However, the symbol in Formula (1) shows the following meanings.
A: a trans-1,4-cyclohexylene group, or a 1,4-phenylene group in which one or more hydrogen atoms in the group may be substituted with a fluorine atom.
Cy: trans-1,4-cyclohexylene group.
m: 1 or 2.
n: 0 or 1.
However, m + n means 1 or 2.
R: When n is 0 or n is 1 and A is a trans-1,4-cyclohexylene group, it is a hydrogen atom or a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms (provided that One or more hydrogen atoms in the aliphatic hydrocarbon group may be substituted with a halogen atom, and among the carbon-carbon atoms in the aliphatic hydrocarbon group and the bonding terminal of the aliphatic hydrocarbon group An oxygen atom may be inserted into at least one), n is 1, and A is a 1,4-phenylene group in which one or more hydrogen atoms in the group may be substituted with a fluorine atom Is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, a halogen atom or a cyano group.   2. The fluorine-containing liquid crystal compound according to claim 1, wherein R in the formula (1) is a linear alkyl group having 1 to 5 carbon atoms or a fluorine atom when R is a halogen atom.   The fluorine-containing liquid crystal compound according to claim 1 or 2, wherein m in the formula (1) is 1 and n is 0.   A liquid crystal composition comprising 1% by mass or more of the fluorine-containing liquid crystal compound according to claim 1 and 60% by mass or more of another liquid crystal compound.   The liquid crystal composition according to claim 4, comprising 1 to 30% by mass of the fluorine-containing liquid crystal compound and 60% by mass or more of the other liquid crystal compound.   A liquid crystal electro-optical element, wherein the liquid crystal composition according to claim 4 is sandwiched between substrates with electrodes.