JP6136589B2 - Compound, liquid crystal composition, and display element - Google Patents

Description

  The present invention relates to a compound having a terphenyl structure, a liquid crystal composition including the compound, and a display element including the liquid crystal composition.

Liquid crystal display elements (LCDs) are widely used from consumer applications to industrial applications such as liquid crystal televisions, mobile phones, computers, watches, calculators, advertisement display boards, printers, various measuring instruments, automotive panels, and electronic notebooks.
As a display method of the liquid crystal display element, there are TN (twisted nematic) type, STN (super twisted nematic) type, vertical alignment (VA) type using TFT (thin film transistor), IPS (in-plane switching) type, etc. is there.

Examples of the liquid crystal composition used in the liquid crystal display element include a liquid crystal composition having a positive dielectric anisotropy (Δε) and a liquid crystal composition having a negative Δε. In a TN type or STN type horizontal alignment type display, a liquid crystal composition having a positive Δε is used, and in a vertical alignment type, a liquid crystal composition having a negative Δε is used. In the IPS type, a liquid crystal composition having a positive or negative Δε is used. The liquid crystal composition is composed of several to several tens of kinds of compounds in order to optimize dielectric anisotropy (Δε), refractive index anisotropy (Δn), etc. for individual display elements.
In general, many compounds used in liquid crystal compositions are structurally formed from a central skeleton (core) and side groups on both sides (two side chains, or one side chain and one polar group). ing.

There are many characteristics required for liquid crystal devices, but response time is the most important characteristic among them. In a current device using a nematic liquid crystal, the response time is about several milliseconds (milliseconds), and the limit is considered to be about 1 millisecond. Therefore, panel manufacturers are looking for nematic liquid crystal materials that are as fast as possible.
On the other hand, a ferroelectric liquid crystal (FLC) device using a smectic liquid crystal is capable of a high-speed response in principle and can realize a high-speed response of about 0.1 msec. However, materials that have been mainly used as FLC materials so far are generally esters having a phenyl benzoate structure or phenyl pyrimidine compounds, which are difficult to use in TFT devices.

JP-A-11-116512

  A terphenyl compound has been proposed as a compound capable of realizing a smectic liquid crystal (Patent Document 1). However, in order to realize an FLC device that can be used in a wide temperature range, the upper limit temperature at which the smectic C phase (SmC phase) exists is increased, the temperature range of the SmC phase is increased, the inclination angle of the SmC phase ( There is a demand for a liquid crystal compound capable of increasing the tilt angle.

  This invention is made | formed in view of the said situation, The compound which can raise the upper limit temperature in which a SmC phase exists, can expand the temperature range of a SmC phase, or can enlarge the inclination angle of a SmC phase, The said compound is included. An object is to provide a liquid crystal composition and a display element including the liquid crystal composition.

  As a result of intensive studies by the present inventors, it was found that a liquid crystal compound having excellent characteristics can be obtained by introducing a bulky substituent at the terminal of a conventional terphenyl compound, and the present invention was completed.

A first aspect of the present invention is represented by the following general formula (i-1), general formula (i-2) and general formula (i-3) among the compounds represented by the following general formula (i). It is a compound . However, m of the said general formula (i-1) represents the integer of 2-10.

[Wherein, R and R ′ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 9 carbon atoms, and A1, A2 and A3 each independently represent a 1,4-phenylene group. Or 2,3-difluoro-1,4-phenylene group, m represents an integer of 1 to 10, Y represents 1,4-cyclohexylene group, 1,4-phenylene group, 1,4-bicyclooctylene Represents a group or a dialkylsilylene group. ]

The second aspect of the present invention is a liquid crystal composition using the compound of the first aspect.
The third aspect of the present invention is a display device using the liquid crystal composition of the second aspect.

  According to the compound of the present invention, the upper limit temperature at which the SmC phase of the liquid crystal composition containing the compound can exist is increased, the temperature range of the SmC phase of the liquid crystal composition is widened, or the liquid crystal composition The tilt angle can be increased. Therefore, by using the liquid crystal composition containing the compound according to the present invention for a display element, a display element that can be used in a wider temperature range and / or has excellent display characteristics can be obtained.

It is a chart which shows the result of differential scanning calorimetry of a compound (C1). It is a chart which shows the result of differential scanning calorimetry of a compound (C2). It is a chart which shows the result of differential scanning calorimetry of a compound (C3). It is a chart which shows the result of differential scanning calorimetry of a compound (C4). It is a chart which shows the result of differential scanning calorimetry of a compound (C5). It is a chart which shows the result of differential scanning calorimetry of a compound (C6). It is a chart which shows the result of differential scanning calorimetry of a compound (C7). It is a chart which shows the result of differential scanning calorimetry of a compound (C8). It is a chart which shows the result of differential scanning calorimetry of a compound (C11). It is a chart which shows the result of differential scanning calorimetry of a compound (C12).

  Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments, but the present invention is not limited to such embodiments.

<Method for evaluating compounds>
The upper limit temperature of the SmC phase and the temperature range of the SmC phase of the compound according to the present invention and the liquid crystal using the same are the phase series obtained by observing the liquid crystal phase with a differential scanning calorimetry and a polarization microscope equipped with a temperature variable device ( Based on Phase sequence results.

When the upper limit temperature of the SmC phase of the liquid crystal comprising only the compound according to the present invention is higher than the upper limit temperature of the SmC phase of the standard liquid crystal (liquid crystal comprising only the compound of the comparative example (REF1, REF2 or REF3)) Was evaluated as a compound that easily increases the upper limit temperature of the SmC phase of the liquid crystal (having a first increase effect).
The upper limit temperature of the SmC phase expressed by the liquid crystal composition obtained by adding 50 parts by weight of the compound of the present invention to 50 parts by weight of the standard liquid crystal composed of REF2, and the upper limit temperature of the SmC phase expressed by the standard liquid crystal In comparison, when the upper limit temperature of the liquid crystal composition is higher than the upper limit temperature of the standard liquid crystal, the compound of the present invention has an effect of increasing the upper limit temperature of the SmC phase of the liquid crystal composition (second increase). It is effective).

  Further, the temperature range of the SmC phase expressed by the liquid crystal composition obtained by adding 50 parts by weight of the compound of the present invention to 50 parts by weight of the standard liquid crystal composed of REF2 is the temperature of the SmC phase expressed by the standard liquid crystal. When wider than the width, the compound of the present invention was evaluated as having an effect of expanding the temperature width of the SmC phase of the liquid crystal composition. The temperature range of the SmC phase is defined by the upper limit temperature of the SmC phase (the lower limit temperature at which the nematic phase (N phase) or smectic A phase (SmA phase) begins to develop) and the lower limit temperature of the SmC phase (solid phase or other smectic phase). Is the temperature difference).

  When the liquid crystal composed only of the compound according to the present invention expresses the INC phase series, it was evaluated that there was an effect of expanding the tilt angle of the SmC phase. In order to increase the tilt angle of the SmC phase of the liquid crystal, the phase sequence of the liquid crystal is the I phase (isotropic phase) -N phase-SmC phase (INC phase sequence) from the high temperature side. This is because a compound that expresses the INC phase series is preferable to increase the tilt angle of the SmC phase because it is more preferable than -N phase-SmA phase-SmC phase (INAC phase series).

"Compound"
The first aspect of the present invention is a compound represented by the following general formula (i).

In general formula (i), R and R ′ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 9 carbon atoms.
R is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a linear alkyl group having 1 to 10 carbon atoms, and a linear chain having 1 to 8 carbon atoms. The alkyl group is more preferable, and a linear alkyl group having 3 to 7 carbon atoms is particularly preferable.
R ′ is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom or a linear alkyl group having 1 to 8 carbon atoms, An atom or a linear alkyl group having 1 to 5 carbon atoms is more preferable.
When R or R ′ is an alkoxy group, the group is preferably a linear methoxy group, ethoxy group, propoxy group, butoxy group or pentyloxy group.

In general formula (i), A1, A2 and A3 are each independently 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group or 2,3-difluoro. Represents a -1,4-phenylene group.
At least one of A1, A2 and A3 may be a 2-fluoro-1,4-phenylene group, a 3-fluoro-1,4-phenylene group or a 2,3-difluoro-1,4-phenylene group A 2,3-difluoro-1,4-phenylene group is more preferable. More preferably, any one of A1, A2 and A3 is a 2,3-difluoro-1,4-phenylene group, and the remaining two are 1,4-phenylene groups.

  In general formula (i), m represents an integer of 1 to 10.

When A3 is a 2,3-difluoro-1,4-phenylene group and A1 and A2 are 1,4-phenylene groups, m is preferably 1, 3 or 5, or 3 or 5 is more preferable, and 3 is still more preferable.
When m is 3 or 5, the upper limit temperature of the SmC phase of the liquid crystal composition containing the compound represented by the general formula (i) is increased, the temperature range of the SmC phase is expanded, and the inclination angle of the SmC phase is further expanded. (INC phase series is easily expressed). When m is 3, the first ascending effect is easily achieved.

When A2 is a 2,3-difluoro-1,4-phenylene group and A1 and A3 are 1,4-phenylene groups, m is preferably 4 or 5, and preferably 5. Is more preferable.
When m is 4, it is easy to expand the temperature range of the SmC phase and expand the tilt angle (increased INC phase series).
When m is 5, the upper limit temperature of the SmC phase of the liquid crystal composition containing only the compound represented by the general formula (i) and the compound represented by the general formula (i) is increased, and the temperature of the SmC phase is increased. It is easy to enlarge the width and enlarge the tilt angle (increased INC phase series).

When A1 is a 2,3-difluoro-1,4-phenylene group and A2 and A3 are 1,4-phenylene groups, m is preferably 1, 3, or 5.
When m is 1, 3 or 5, it is easy to increase the upper limit temperature of the SmC phase of the liquid crystal composed only of the compound represented by the general formula (i).

In general formula (i), Y represents any group of a 1,4-cyclohexylene group, a 1,4-phenylene group, a 1,4-bicyclooctylene group, or a dialkylsilylene group. By Y being the structurally bulky group shown here, it becomes easier to improve at least one of the upper limit temperature of SmC, the temperature range of the SmC phase, and the inclination angle of the SmC phase as compared with the conventional compound. .
Any one or more of hydrogen atoms bonded to the 1,4-cyclohexylene group, 1,4-phenylene group, 1,4-bicyclooctylene group and dialkylsilylene group may be substituted with a fluorine atom. Absent. The first alkyl group and the second alkyl group of the dialkylsilylene group are preferably each independently a linear or branched alkyl group having 1 to 4 carbon atoms, and a straight chain having 1 to 4 carbon atoms. It is more preferably a chain alkyl group.
Y is preferably 1,4-cyclohexylene group, 1,4-phenylene group or 1,4-bicyclooctylene group, and is 1,4-cyclohexylene group or 1,4-phenylene group. Are more preferable, and a 1,4-cyclohexylene group is still more preferable.

  As a preferable compound represented by the said general formula (i), the compound represented by the following general formula (i-0) is mentioned, for example.

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 9 carbon atoms, and A1, A2, and A3 are those represented by A1, A2, and A3 in the general formula (i), respectively. The same group as description is represented, m represents the integer of 1-10, n represents the integer of 0-10. ]

  n is preferably 0 to 3, more preferably 0 to 2, and even more preferably 0 or 1 from the viewpoint of expanding the inclination angle of the SmC phase (expressing the INC phase series).

  As a preferable compound represented by the said general formula (i-0), the compound represented by the following general formula (i-1) is mentioned, for example.

[In formula, R represents a hydrogen atom, a C1-C10 alkyl group, or a C1-C9 alkoxy group, m represents the integer of 1-10, n represents the integer of 0-10. ]
The description of R, m and n is the same as the description of R, m and n in the general formula (i-0).

  As a preferable combination of m and n in the general formula (i-1), (m, n) = (5,0), (5,1), (4,2), (3,3), (2,4 ), (1, 5). Among these combinations, when (m, n) = (3, 3) or (1, 5), the upper limit temperature of the SmC phase can be further increased (the first increasing effect is further exhibited). ) And the effect of expanding the temperature range of the SmC phase can be easily obtained. Further, when (m, n) = (5,0), (5,1), (3,3), the second effect of increasing the upper limit temperature of the SmC phase and the expansion of the temperature range of the SmC phase. The effect and the effect of expanding the tilt angle of the SmC phase can be easily obtained.

  As a preferable compound represented by the said general formula (i-1), the compound represented by the following general formula (i-1-1) is mentioned, for example.

[Wherein, m represents an integer of 1 to 10, and n represents an integer of 0 to 10. ]
The explanation of m and n is the same as the explanation of R, m and n in the general formula (i-1).

  As a preferable compound represented by the said general formula (i-0), the compound represented by the following general formula (i-2) is mentioned, for example.

[In formula, R represents a hydrogen atom, a C1-C10 alkyl group, or a C1-C9 alkoxy group, m represents the integer of 1-10, n represents the integer of 0-10. ]
The description of R, m and n is the same as the description of R, m and n in the general formula (i-0).

  As a preferable combination of m and n in the general formula (i-2), (m, n) = (5,0), (5,1), (4,2), (3,3), (2,4 ), (1, 5). Among these combinations, when (m, n) = (5, 1), the first increase effect and the second increase effect of the upper limit temperature of the SmC phase, the expansion effect of the temperature range of the SmC phase, and The effect of increasing the tilt angle of the SmC phase can be easily obtained. Further, when (m, n) = (4, 2), the effect of expanding the temperature width of the SmC phase and the effect of expanding the tilt angle of the SmC phase can be easily obtained. Further, when (m, n) = (5, 0), the first effect of increasing the upper limit temperature of the SmC phase and the effect of expanding the tilt angle of the SmC phase can be easily obtained.

  As a preferable compound represented by the said general formula (i-2), the compound represented by the following general formula (i-2-1) is mentioned, for example.

[Wherein, m represents an integer of 1 to 10, and n represents an integer of 0 to 10. ]
The description of m and n is the same as the description of m and n in the general formula (i-2).

  As a preferable compound represented by the said general formula (i-0), the compound represented by the following general formula (i-3) is mentioned, for example.

[In formula, R represents a hydrogen atom, a C1-C10 alkyl group, or a C1-C9 alkoxy group, m represents the integer of 1-10, n represents the integer of 0-10. ]
The description of R, m and n is the same as the description of R, m and n in the general formula (i-0).

  As a preferable combination of m and n in the general formula (i-3), (m, n) = (5,0), (5,1), (4,2), (3,3), (2,4 ), (1, 5). Among these combinations, when (m, n) = (5,1), (3,3) or (1,5), the first effect of increasing the upper limit temperature of the SmC phase can be easily obtained. When (m, n) = (3, 3), the first increase effect can be further enhanced.

  As a preferable compound represented by the said general formula (i-3), the compound represented by the following general formula (i-3-1) is mentioned, for example.

[Wherein, m represents an integer of 1 to 10, and n represents an integer of 0 to 10. ]
The description of m and n is the same as the description of m and n in the general formula (i-3).

<Liquid crystal composition>
The liquid crystal composition according to the second aspect of the present invention may be a liquid phase composition composed only of the compound represented by the general formula (i) or the compound represented by the general formula (i). And a liquid phase composition containing other compounds. The liquid crystal composition of the present invention is preferably a ferroelectric liquid crystal composition.
When the liquid crystal composition of the present invention is a ferroelectric liquid crystal composition, the liquid crystal composition preferably contains an optically active compound. The optically active compound that can be contained in the liquid crystal composition of the present invention is not particularly limited, and a compound having a known asymmetric atom, a compound having axial asymmetry, or a compound having surface asymmetry can be used. A compound having an asymmetric carbon or a compound having a carbon-carbon bond as an axial asymmetry is preferably used, and a compound having an asymmetric carbon atom is more preferable.

In an optically active compound having an asymmetric carbon, the asymmetric carbon may be introduced into a part of a chain structure or a part of a cyclic structure, and a fluorine atom or a methyl group may be present on the asymmetric carbon. Alternatively, a compound having a CF ₃ group introduced therein or a compound having an oxirane ring structure having an asymmetric carbon is preferable.
Specifically, the optically active compound is represented by the general formula (III)

(In the formula, R ³¹ and R ³² each independently represent a linear or branched alkyl group having 1 to 18 carbon atoms, and one or two non-adjacent —CH in the alkyl group. _{The 2-} group is replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CH═CH— or —C≡C—. The hydrogen atom in the alkyl group may be replaced with a fluorine atom or a CN group, and A ³ , B ³ and C ³ are each independently a 1,4-phenylene group, pyrazine-2,5 -Diyl group, pyridazine-3,6-diyl group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, trans-1,4-cyclohexylene group, 1,3,4-thiadiazole- 2,5-diyl group, 1,3-dioxane-2,5-diyl group, 1,3-dithiane 2,5-diyl group, 1,3-thiazole-2,4-diyl, 1,3-thiazole-2,5-diyl, thiophene-2,4-diyl group, thiophene-2,5-diyl group, piperazine -1,4-diyl group, piperazine-2,5-diyl group or naphthalene-2,6-diyl group, provided that the hydrogen atom in the 1,4-phenylene group and naphthalene-2,5-diyl group May be substituted by a fluorine atom, a CF ₃ group, an OCF ₃ group, a CN group, a CH ₃ group, or an OCH ₃ group, and the hydrogen atom in the trans-1,4-cyclohexylene group is a CN group or Optionally substituted with a CH ₃ group, a ³ , b ³ , and c ³ each independently represent 0 or 1, L ³¹ and L ³² each independently represent a single bond, —O—, —CO— _{, -CH 2 O -, - OCH} 2 -, - CF 2 O-, —OCF ₂ —, —CO—O—, —O—CO—, —O—CO—O—, —CH ₂ CH ₂ —, —CH═CH— or —C≡C—, L ³³ is Formula (III-1),

(Wherein d ³ represents an integer of 0 or more and 8 or less, and X represents —O—, —CO—O—, or —O—CO—). ³¹ represents the general formula (III-4) or the general formula (III-5),

(However, Z ³² represents a fluorine atom, a methyl group or a CF ₃ group, R ³³ and R ³⁴ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, * Represents an asymmetric carbon). ) Is preferred. The a ³ + b ³ + c ³ is preferably 2 or 3.

Among the compounds represented by the general formula (III), in particular, Z ³¹ has a structure of the general formula (III-4) and Z ³² is a fluorine atom, or Z ³¹ is the general formula (III-5). More preferred is a compound having the following structure, and R ³³ and R ³⁴ are hydrogen atoms.
Among the compounds represented by the general formula (III), Z ³¹ has the structure of the general formula (III-4) and Z ³² is a fluorine atom, and the following general formula (III-b)

Wherein R ³⁷ and R ³⁸ each independently represent a linear or branched alkyl group having 1 to 18 carbon atoms, and one or two non-adjacent —CH in the alkyl group _{The 2-} group is replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —CH═CH— or —C≡C—. The hydrogen atom in the alkyl group may be replaced with a fluorine atom or a CN group, and L ³⁴ is a group represented by the general formula (III-b-1), or the general formula (III-b-2),

(Wherein g ³ and h ³ each independently represents an integer of 0 or more and 7 or less). Or a compound represented by the following general formula (III-c)

(In the formula, R ³⁹ and R ⁴⁰ each independently represent a linear or branched alkyl group having 1 to 18 carbon atoms, provided that at least one of the alkyl groups is a branched alkyl group. And one or two non-adjacent —CH ₂ — groups in the alkyl group are —O—, —CO—, —CO—O—, —O—CO—, —O—CO—O—. , -CH = CH- or -C≡C-, one or more hydrogen atoms in the alkyl group may be replaced by a fluorine atom or a CN group, and X ³¹ and X ³² are Each independently represents a hydrogen atom or a fluorine atom, d ³ represents an integer of 0 or 1, and L ³⁵ represents a general formula (III-c-1), a general formula (III-c-2), or a general formula ( III-c-3),

(Wherein j ³ , k ³ , and m ³ each independently represents an integer of 0 or more and 7 or less). ).

Among these compounds, in the case of the compound represented by the general formula (III-b), R ³⁷ and R ³⁸ are more preferably a linear or branched alkyl group, and particularly preferably a linear alkyl group. On the other hand, in the case of the compound represented by the general formula (III-c), R ³⁹ is more preferably a linear or branched alkyl group, alkoxy group, alkenyl group, alkenyloxy group, and R ⁴⁰ is linear or A branched alkyl group is preferable, and a linear alkyl group is particularly preferable.
Among the compounds represented by the general formula (III), the compound having the following structure is preferred as a compound in which Z ³¹ has the structure of the general formula (III-5) and R ³³ and R ³⁴ are hydrogen atoms.

Wherein R ³³¹ is an alkyl group having 4 to 14 carbon atoms or an alkoxy group, R ³³² is an alkyl group having 1 to 8 carbon atoms, R ³³³ is an alkyl group having 4 to 14 carbon atoms, L ³³¹ and L ³³² are Each independently represents a carbonyl group or a methylene group.)
Specific examples of particularly preferable compounds as the general formula (III) are shown below.

(In the formula, R _aa is a linear or branched alkyl group or alkoxy group having 1 to 18 carbon atoms, R _bb is a linear or branched alkyl group having 1 to 18 carbon atoms, and M _aa is a carbon number. 1 to 3 methylene groups, and M _bb represents a methylene group having 1 to 2 carbon atoms.)

  The liquid crystal composition of the present invention contains a compound represented by the general formula (i). 5-80 mass% is preferable and, as for content of the compound represented by general formula (i) with respect to the gross mass of the liquid-crystal composition of this invention, 10-60 mass% is more preferable. The liquid crystal composition of the present invention preferably contains two or more compounds represented by the general formula (i).

  When the liquid crystal composition of the present invention is a ferroelectric liquid crystal composition, it is preferable to use a chiral compound represented by the general formula (III) in addition to the compound represented by the general formula (i). The content of the compound represented by the general formula (III) with respect to the total mass of the ferroelectric liquid crystal composition is preferably 2 to 50% by mass, and more preferably 5 to 30% by mass. Moreover, when content of general formula (III) exceeds 10 mass%, 2 or more types of compounds represented by general formula (III) are used, and content of a single component does not exceed 10 mass% By doing so, it is possible to suppress undesirable crystallization and disorder of the phase sequence.

For the purpose of removing impurities or the like from the liquid crystal composition, or for the purpose of further increasing the specific resistance value of the liquid crystal composition, purification treatment with silica, alumina or the like may be performed. The specific resistance value is preferably 10 ¹² Ω · cm or more, more preferably 10 ¹³ Ω · cm or more. Furthermore, dopants such as chiral compounds, dyes, and ion scavengers can be added to the liquid crystal composition according to the purpose.

  In addition, antioxidants, UV absorbers, non-reactive oligomers and inorganic fillers, organic fillers, polymerization inhibitors, antifoaming agents, leveling agents, plasticizers, silane coupling agents, etc. are added as necessary. You may do it.

  Furthermore, as a component of the ferroelectric liquid crystal composition, a liquid crystal compound other than the liquid crystal compound represented by the general formula (i) can be used in combination as necessary. The compound that can be used in combination is not particularly limited, but in order to stabilize the ferroelectric liquid crystal phase, it is preferable to use a liquid crystal compound exhibiting an SmC phase or a chiral SmC phase. (In this specification, the name of the liquid crystal phase includes the corresponding chiral liquid crystal phase unless otherwise specified.) In addition, the phase sequence of the ferroelectric liquid crystal phase or the temperature range of each liquid crystal phase is defined. In order to adjust, it is preferable to select a liquid crystal compound as appropriate. Specifically, when it is desired to develop the N phase or to expand the temperature range of the nematic phase, it is preferable to use a compound exhibiting the N phase together, and to develop the SmA phase or the temperature range of the SmA phase. When it is desired to expand the range, it is preferable to use a compound exhibiting an SmA phase, or, when a SmA phase is unnecessary, such as a Half-V material, a compound not exhibiting an SmA phase may be used in combination. preferable. Specific examples preferable as a compound to be used in combination for stabilizing the ferroelectric liquid crystal phase are given below.

Wherein R ⁶⁶¹ and R ⁶⁶² are each independently an alkyl group having 4 to 14 carbon atoms, R ⁶⁶³ and R ⁶⁶⁴ are each independently an alkyl group or alkoxy group having 4 to 14 carbon atoms, and R ⁶⁶⁵ is an alkyl group having 4 to 4 carbon atoms. 14 alkyl groups, L ⁶⁶¹ and L ⁶⁶² are each independently a single bond, —O—, —COO— or —OCO—, L ⁶⁶³ is a single bond, —O—, —COO—, —OCO— or — CH ₂ —CH ₂ —, X ⁶⁶¹ , X ⁶⁶² , X ⁶⁶³ , X ⁶⁶⁴ , X ⁶⁶⁵ , and X ⁶⁶⁶ each independently represent a hydrogen atom or a fluorine atom.)
In order to obtain a display element with good contrast, it is necessary to adjust the tilt angle according to the display method. In order to increase the tilt angle, it is preferable to select a compound so as to increase the upper limit temperature of the SmC phase or to narrow the temperature range of the SmA phase, and in order to decrease the tilt angle, the upper limit of the SmC phase. It is preferable to use a compound that lowers the temperature or widens the temperature range of the SmA phase.

  In order to stabilize the layer structure of the Sm phase, the liquid crystal composition of the present invention preferably contains a phenylbenzoate derivative or a biphenylbenzoate derivative. Since these phenylbenzoate derivatives or biphenylbenzoate derivatives increase the viscosity of the composition, it is possible to stabilize the layer structure of the Sm phase and to suppress alignment disorder. Further, the effect of lowering the melting point can be obtained by the addition of the phenylbenzoate derivative. However, the use of the phenylbenzoate derivative increases the viscosity and slows the response speed. Therefore, it is desirable to use the phenylbenzoate derivative within a range in which a desired response speed can be obtained.

  The compounds represented by the general formula (i) may be used alone or in combination of a plurality of compounds having different alkyl chain lengths, alkyl chain structures, bond structure, ring structures, and ring numbers. In order to improve the stability of the liquid crystal temperature, it is preferable to use two or more compounds having different structures.

    The chiral compound contained in the liquid crystal composition of the present invention may be a single compound having a structure represented by the general formula (III), or a chiral structure, an alkyl chain length, an alkyl chain structure, A plurality of different structures, ring structures, and ring numbers may be used in combination. In order to suppress the helical structure in the liquid crystal phase generated based on the chiral effect and obtain a good alignment state, it is preferable to use a combination of a plurality of chiral compounds having different directions of twisting to be generated. At this time, by selecting a combination of chiral compounds so that the directions of spontaneous polarization are aligned, or by selecting a combination of a compound that generates a sufficiently large spontaneous polarization and a compound that induces a twisted structure but has a small spontaneous polarization value, Spontaneous polarization values are preferred because they are not canceled. In order to suppress the generation of a helical structure that occurs in the liquid crystal phase based on the chiral effect, it is also preferable to introduce a plurality of chiral structures having different twist directions to be introduced into the same compound. At this time, by selecting a combination of chiral structures so that the directions of spontaneous polarization are aligned, or by selecting a combination of a structure that generates a sufficiently large spontaneous polarization and a structure that induces a twisted structure but has a small spontaneous polarization value, Spontaneous polarization values are preferred because they are not canceled.

  A liquid crystal display element can be produced by placing the liquid crystal composition of the present invention in a liquid crystal cell. For the two substrates of the liquid crystal cell, a transparent material having flexibility such as glass and plastic can be used. One substrate may be an opaque material such as silicon. A transparent substrate having a transparent electrode layer can be obtained, for example, by sputtering indium tin oxide (ITO) on a transparent substrate such as a glass plate.

  A liquid crystal display element using a ferroelectric liquid crystal composition can display a color without using a color filter by using a field sequential driving method, but a display method using a color filter is used. May be. The color filter can be prepared by, for example, a pigment dispersion method, a printing method, an electrodeposition method, or a dyeing method. A method for producing a color filter by a pigment dispersion method will be described as an example. A curable coloring composition for a color filter is applied on the transparent substrate, subjected to patterning treatment, and cured by heating or light irradiation. By performing this process for each of the three colors red, green, and blue, a pixel portion for a color filter can be created. In addition, a pixel electrode provided with an active element such as a TFT, a thin film diode, or a metal insulator metal specific resistance element may be provided on the substrate.

  The said board | substrate is made to oppose so that a transparent electrode layer may become an inner side. In that case, you may adjust the space | interval of a board | substrate through a spacer. In this case, it is preferable to adjust the thickness of the obtained cell to be 1 to 100 μm. The cell thickness is more preferably 1 to 10 μm, still more preferably 1 to 4 μm. When a polarizing plate is used, it is preferable to adjust the product of the refractive index anisotropy Δn of the liquid crystal and the cell thickness d so that the contrast is maximized. In view of manufacturing the display element, it is preferable that the cell thickness is thick. In that case, it is necessary to use a liquid crystal having a small Δn. In that case, cyclohexyl, a compound of general formula (i) or general formula (III) having a 1,3,4-thiadiazole-2,5-diyl structure, or general formula (i) or general formula ( It is desirable to use a compound other than III) that has cyclohexyl or 1,3,4-thiadiazole-2,5-diyl structure. One or two cyclohexyl structures are preferably present in one molecule, and one 1,3,4-thiadiazole-2,5-diyl is preferably present in one molecule. In addition, when there are two polarizing plates, the polarizing axis of each polarizing plate can be adjusted so that the viewing angle and contrast are good. Furthermore, a retardation film for widening the viewing angle can also be used. Examples of the spacer include glass particles, plastic particles, alumina particles, and a photoresist material. Thereafter, a sealant such as an epoxy thermosetting composition is screen-printed on the substrates with a liquid crystal inlet provided, the substrates are bonded together, and heated to thermally cure the sealant.

  As a method for sandwiching a ferroelectric liquid crystal composition stabilized with a polymer between two substrates, a normal vacuum injection method, an ODF method, or the like can be used. At this time, the liquid crystal composition is preferably in a uniform isotropic state or in a (chiral) N phase. In the Sm phase, handling during device fabrication becomes difficult.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

<< Synthesis 1 >>
Synthesis of 4- (2,3-difluoro- (4- (4-pentylphenyl)) phenyl) phenol

<Synthesis 1-1>
Synthesis of 2,3-difluoro-4'-pentylbiphenyl

  148.3 g 4-pentylphenylboric acid, 102 g 1-bromo-2,3-difluorobenzene, 5.56 g tetrakistriphenylphosphine palladium (0) complex and 270 g hydrogen carbonate in a nitrogen-substituted 3 L four-necked flask Sodium and 750 ml of N, N-dimethylacetamide were added and stirred at 100 degrees for 8 hours. The completion of the reaction was confirmed by gas chromatography (GC), and the system was cooled to room temperature. 1 L of water was added to the reaction system and stirred, and 1 L of heptane was added and stirred vigorously. The organic layer was separated and then extracted twice with 1 L of heptane. The obtained heptane solution was washed twice with 300 ml of water, and then the solvent was distilled off. Purification was performed using 250 g of silica gel using heptane as a solvent, and 100 g of the target product was obtained as a colorless transparent liquid. . Yield 72.8%. GC purity 97.7%. M + 260.

<Synthesis 1-2>
Synthesis of 2, 3-difluoro-4-iodo-4'-pentylbiphenyl

  30.75 g of 2,3-difluoro-4′-pentylbiphenyl was added to a nitrogen-substituted 1 L four-necked flask, and this was dissolved in 100 ml of THF and cooled to −78 degrees. To the system, 100 ml of 1.3M sec-butyllithium was added dropwise over 30 minutes. After 5 hours, a solution of 35.6 g of iodine dissolved in 100 ml of THF was added dropwise over 30 minutes. Thereafter, the temperature of the system was raised to room temperature over 8 hours. 500 ml heptane was added to the system and this solution was washed with 500 ml saturated aqueous sodium sulfite. The solvent was distilled off, and purification was performed using 50 g of silica gel using heptane as a solvent. As a result, 43 g of the intended product was obtained as a pale yellow liquid. Yield 94.3%. GC purity 85.98%. M + 386.

<Synthesis 1-3>
Synthesis of 4- (2,3-difluoro- (4- (4-pentylphenyl)) phenyl) phenol

  Nitrogen-substituted 2 L four-necked flask with 60.8 g of 4-hydroxyphenylboric acid, 172 g of 2,3-difluoro-4-iodo-4'-pentylbiphenyl, 261.5 g of 40% aqueous potassium carbonate, 44.38 g of tetrakis The triphenylphosphine palladium (0) complex was dissolved in 500 ml of N, N-dimethylacetamide and stirred at 110 degrees for 6 hours. After confirming the completion of the reaction by GC, the reaction mixture was cooled to room temperature, and 100 ml of 18% hydrochloric acid was added thereto. Furthermore, 200 ml of ethyl acetate was added and stirred, and the organic layer was separated. Subsequently, extraction was performed twice using 200 ml of ethyl acetate. The organic layers were combined and washed with 200 ml of water and then with 200 ml of saturated brine. After the solvent was distilled off, purification was performed using 200 g of silica gel using a mixed solvent of ethyl acetate: heptane (1: 5) as the solvent, followed by recrystallization using ethanol and acetone. As a white solid 123.5 g of the target product was obtained. Yield 78.8%. GC purity 99.5%. M + 352.

<< Synthesis 2 >>
Synthesis of 4- (4- (2,3-difluoro-4-pentylphenyl) phenyl) phenol

<Synthesis 2-1>
Synthesis of butyltriphenylphosphonium bromide

  280 g of butane bromide and 696 g of triphenylphosphine were dissolved in 500 ml of xylene in a nitrogen-substituted 2 L four-necked flask, which was heated to a temperature at which xylene was refluxed and stirred for 6 hours. The system was cooled to room temperature, and the precipitated white crystals were filtered out and washed with xylene. As a result of drying, 797 g of the desired product was obtained as a white solid. Yield 97.7%.

<Synthesis 2-2>
Synthesis of 1,2-difluoro-3- (1-pentenyl) benzene

  797 g of butyltriphenylphosphonium bromide was suspended in 1 L of THF in a nitrogen-substituted 3 L four-necked flask and cooled to −10 degrees, and 224 g of potassium t-butoxide was slowly added thereto. After 1 hour, the system was brought to 0 degree and 248 g of 2,3-difluorobenzaldehyde was added slowly and left overnight with stirring. 50 ml of water was added to the system, the solvent was distilled off, and 2 L of heptane was added to extract the target product. The obtained heptane solution was washed with a 40% aqueous methanol solution, the solvent was distilled off, and purification was performed using 1000 g of silica gel using heptane as a solvent. As a result, 343 g of the desired product was obtained as a pale yellow liquid. Yield 93.6%. GC purity 87%. M + 182.

<Synthesis 2-3>
Synthesis of 1,2-difluoro-3-pentylbenzene

  In a 2 L autoclave, 343 g of 1,2-difluoro-3- (1-pentenyl) benzene was dissolved in 1 L of THF, 10 g of 5% palladium carbon was added thereto, the system was purged with nitrogen, and then 0.2 MPa. The mixture was stirred for 4 hours in a hydrogen atmosphere. After confirming the completion of the reaction by GC, palladium carbon was filtered off and the solvent was distilled off. Purification was performed using 300 g of silica gel using heptane as a solvent, and 345 g of the target product was obtained as a colorless liquid. Yield 89.6%. GC purity 90%. M + 184.

<Synthesis 2-4>
Synthesis of 2,3-difluoro-4-pentylphenylboric acid

  In a 2 L four-necked flask purged with nitrogen, 143 g of 1,2-difluoro-3-pentylbenzene was dissolved in 500 ml of THF and cooled to -78 degrees. To this, 486 ml of 1.6 M butyllithium hexane solution was added over 2 hours. After 1 hour, 81 g of trimethyl borate was added dropwise over 1 hour. The system temperature was then raised to room temperature over 1 hour. 500 ml of 10% hydrochloric acid was added and stirred for 2 hours. 500 ml of heptane was added to the system and stirred, and the organic layer was separated. Further, extraction with 300 ml of heptane was performed, and the organic layer was combined and washed with 300 ml of saturated saline. The solvent was distilled off to obtain 152.1 g of the desired product as a pale yellow solid. Yield 95.4%.

<Synthesis 2-5>
Synthesis of 4- (4- (2,3-difluoro-4-pentylphenyl) phenyl) phenol

  In a nitrogen-substituted 2 L four-necked flask, 152.1 g of 2,3-difluoro-4-pentylphenylboric acid, 156.6 g of 4- (4-bromophenyl) phenol, 40% aqueous potassium carbonate 434 g, 47.27 g of tetrakis The triphenylphosphine palladium (0) complex was dissolved in 500 ml of N, N-dimethylacetamide and stirred at 110 degrees for 6 hours. After confirming the completion of the reaction by GC, the reaction mixture was cooled to room temperature, and 400 ml of 18% hydrochloric acid was added thereto. Furthermore, 200 ml of ethyl acetate was added and stirred, and the organic layer was separated. Subsequently, extraction was performed 3 times using 200 ml of ethyl acetate. The organic layers were combined and washed with 200 ml of water and then with 200 ml of saturated brine. After the solvent was distilled off, purification was performed using 300 g of silica gel using a mixed solvent of ethyl acetate: heptane (1: 5) as the solvent, followed by recrystallization using ethanol and acetone. As a white solid, 199 g The desired product was obtained. Yield 89.9%. GC purity 99.3%. M + 352.

<< Synthesis 3 >>
Synthesis of 3- (4-propylcyclohexyl) propyl methanesulfonate

<Synthesis 3-1>
Synthesis of ethyl 4-propylcyclohexanecarboxylate

  In a 1 L flask, 120 g of 4-propylcyclohexanecarboxylic acid is dissolved in 250 ml of ethanol, and 0.5 ml of concentrated sulfuric acid is added thereto. After heating at reflux for 2 hours, 200 ml of the solvent is distilled off. The solution is dropped into ice water, and toluene is added to separate the solution. The organic layer is washed with water, then with 10% aqueous sodium hydrogen carbonate solution, and then with saturated brine. The solvent was distilled off to obtain 136 g of the desired product as a pale yellow liquid. Yield 97%. M + 198.

<Synthesis 3-2>
Synthesis of 1- (4-propylcyclohexyl) methanol

  In a 2 L four-necked flask purged with nitrogen, 21.4 g of lithium aluminum hydride is suspended in 1 L of THF. The system was cooled to 0 ° C., and a solution of 136 g of ethyl 4-propylcyclohexanecarboxylate dissolved in 200 ml of THF was added dropwise over 1 hour. The reaction solution was stirred for 3 hours, and after confirming the completion of the reaction by GC, 200 g of 18% hydrochloric acid was slowly added dropwise. After liquid separation, toluene was added to the aqueous layer, extraction was performed twice, and the combined organic layer was washed with water. The solvent was distilled off to obtain 100 g of the desired product as a pale yellow liquid. Yield 99%. GC purity 91.5%. M + 156.

<Synthesis 3-3>
Synthesis of 1- (bromomethyl) -4-propylcyclohexane

  A 5-L four-necked flask was charged with 100 g of 1- (4-propylcyclohexyl) methanol and 6.53 g of red phosphorus and heated to 80 degrees. To this was added 66.3 g of bromine, and the system was stirred at 120 ° C. for 3 hours. After confirming the completion of the reaction by GC, the system was cooled to room temperature. The solid was filtered through silica gel and washed out with 1 L of hexane. The obtained filtrate was washed with water and then with saturated brine. The solvent was distilled off to obtain 118 g of the desired product as a transparent liquid. Yield 97%. GC purity 84%. M + 218.

<Synthesis 3-4>
Synthesis of 2- (4-propylcyclohexyl) acetaldehyde

  15.5 g of magnesium was placed in a 1 L four-necked flask purged with nitrogen, and a solution prepared by dissolving 118 g of 1- (1-bromomethyl) -4-propylcyclohexane in 250 ml of THF was added dropwise thereto. Thereafter, the system was cooled to −5 ° C., and 78 g of N, N-dimethylformamide was added dropwise over 30 minutes. After stirring for 1 hour, 250 ml of 18% hydrochloric acid was added dropwise. After separation, 300 ml of hexane was added to the aqueous layer, and the mixture was extracted three times. The organic layer was washed with water, then washed with a 10% aqueous sodium hydrogen carbonate solution, and further washed with saturated saline. The solvent was distilled off to obtain 86 g of the desired product as a transparent liquid. Yield 98%. GC purity 87%. M + 168.

<Synthesis 3-5>
Synthesis of 1- (3-methoxy-2-propenyl) -4-propylcyclohexane

  206.3 g of methoxymethyltriphenylphosphonium chloride was suspended in 500 ml of THF in a nitrogen-substituted 2 L four-necked flask and cooled to −5 degrees. To this, 67.2 g of potassium t-butoxide was added little by little. After 1 hour, 86 g of 2- (4-propylcyclohexyl) acetaldehyde was slowly added and stirred for 4 hours. After confirming the reaction by GC, 100 ml of water was added to the system. After the solvent was distilled off, hexane was added to form a hexane solution, which was then washed with water. When purification was performed using 100 g of silica gel, 89 g of the desired product was obtained as a colorless liquid. Yield 82%. GC purity 80%. M + 196.

<Synthesis 3-6>
Synthesis of 3- (4-propylcyclohexyl) propanal

  89 g of 1- (3-methoxy-2-propenyl) -4-propylcyclohexane is dissolved in 350 ml of THF in a nitrogen-substituted 1 L four-necked flask, and 350 g of 12% hydrochloric acid is added thereto. The system was heated to reflux for 5 hours. The completion of the reaction was confirmed by GC and cooled to room temperature. Toluene was added for liquid separation, and the organic layer was washed with water. The solvent was distilled off to obtain 75 g of the desired product as a colorless liquid. Yield 99%. GC purity 87.2%. M + 182.

<Synthesis 3-7>
Synthesis of 3- (4-propylcyclohexyl) -1-propanol

  7.41 g of lithium aluminum hydride was suspended in 500 ml of THF in a nitrogen-substituted 2 L four-necked flask, and the system was cooled to 5 degrees. A solution prepared by dissolving 75 g of 3- (4-propylcyclohexyl) propanal in 100 ml of THF was slowly added dropwise. After confirming the completion of the reaction by GC, 20 ml of water was added, followed by 500 ml of 18% hydrochloric acid. Toluene was added for liquid separation, and extraction from the aqueous layer was further performed twice using toluene. The organic layers were combined and washed 3 times with saturated brine. After anhydrous magnesium sulfate was added and dried, the solvent was distilled off to obtain 68 g of the desired product as a yellow liquid. Yield 91%. GC purity 89%. M + 184.

<Synthesis 3-8>
Synthesis of 3- (4-propylcyclohexyl) propyl methanesulfonate

  In a 1 L four-necked flask, 68 g of 3- (4-propylcyclohexyl) -1-propanol was dissolved in 500 ml of dichloromethane, and 41.5 g of pyridine was added and cooled to 0 degrees. 44.1 g of methanesulfonic acid chloride was slowly added dropwise and stirred for 6 hours. The system was returned to room temperature and 300 ml of water was added. After separation, the organic layer was washed with saturated brine. The solvent was distilled off and recrystallized from methanol to obtain 70 g of the desired product as white crystals. Yield 76%. GC purity 94%. M + 262.

<< Synthesis 4 >>
Synthesis of 5- (4-methylcyclohexyl) pentyl methanesulfonate

<Synthesis 4-1>
Synthesis of 1- (4-methylcyclohexyl) methanol

  38.5 g of lithium aluminum hydride was suspended in 400 ml of THF in a 2 L four-necked flask purged with nitrogen and cooled to 0 ° C. A solution of 110 g of 4-methylcyclohexanecarboxylic acid dissolved in 400 ml of THF was slowly added dropwise and stirred for 6 hours. After confirming the completion of the reaction by GC, 30 ml of water was added, and then 500 g of 18% hydrochloric acid was added. After separation, the aqueous layer was extracted twice with dichloromethane, washed with the previous organic layer, and then with saturated brine. The solvent was distilled off to obtain 100 g of the desired product as a yellow liquid. Yield 100%. GC purity 99%. M + 128.

<Synthesis 4-2>
Synthesis of 1- (bromomethyl) -4-methylcyclohexane

  99 g of 1- (4-methylcyclohexyl) methanol and 86 g of triethylamine were dissolved in 500 ml of THF in a nitrogen-substituted 2 L four-necked flask. 97 g of mesyl chloride was added dropwise at room temperature and stirred for 2 hours. The reaction solution was cooled, the precipitate was filtered off, 84 g of lithium bromide was added to the filtrate, and the mixture was stirred at 60 ° C. for 6 hours. After confirming the reaction by GC, the solvent was distilled off and distillation was carried out to obtain 85 g of the objective product as a colorless and transparent liquid. Yield 58%. GC purity 98%. M + 190.

<Synthesis 4-3>
Synthesis of 2- (4-methylcyclohexyl) acetaldehyde

  A 1L four-necked flask purged with nitrogen was charged with 12.7 g of magnesium, and a solution of 83.88 g of 1- (1-bromomethyl) -4-methylcyclohexane dissolved in 200 ml of THF was added dropwise to prepare a Grignard reagent. Thereafter, 64 g of N, N-dimethylformamide which was cooled to −5 ° C. and dried was added dropwise over 30 minutes. Thereafter, 200 ml of 18% hydrochloric acid was added dropwise, and 300 ml of hexane was further added for liquid separation. The aqueous layer was extracted twice with 300 ml of hexane, combined with the previous organic layer, washed with water and then with saturated brine. The solution was dried using anhydrous sodium sulfate, the solvent was distilled off and then distilled to obtain 57 g of the objective product as a colorless transparent liquid. Yield 92%. GC purity 94%. M + 140.

<Synthesis 4-4>
Synthesis of 1-methyl-4- (3-methoxy-2-propenyl) cyclohexane

  134.4 g of methoxymethyltriphenylphosphonium chloride was suspended in 500 ml of THF in a nitrogen-substituted 2 L four-necked flask and cooled to 0 ° C. To this, 43.7 g of potassium t-butoxide was added little by little. After 1 hour, 42.14 g of 2- (4-methylcyclohexyl) acetaldehyde was slowly added and stirred for 4 hours. After confirming the reaction by GC, 100 ml of water was added to the system. After the solvent was distilled off, hexane was added to form a hexane solution, which was then washed with water. The solution was dried using anhydrous sodium sulfate, the solvent was distilled off and then distilled to obtain 35 g of the objective product as a colorless transparent liquid. Yield 69%. GC purity 94%. M + 168.

<Synthesis 4-5>
Synthesis of 3- (4-methylcyclohexyl) propanal

  A 1-L four-necked flask substituted with nitrogen was charged with 35 g of 1-methyl-4- (3-methoxy-2-propenyl) cyclohexane, 176 ml of 12% hydrochloric acid and 120 ml of THF, and stirred at reflux temperature for 5 hours. The system was cooled to room temperature and separated, and the organic layer was washed with water and the solvent was distilled off to obtain 32 g of the desired product as a colorless and transparent liquid. Yield 100%. GC purity 95%. M + 154.

<Synthesis 4-6>
Synthesis of ethyl 5- (4-methylcyclohexyl) -2-pentenoate

  98 g of ethoxycarbonylmethyl (triphenyl) phosphonium bromide was suspended in 300 ml of THF in a 1 L four-necked flask purged with nitrogen and cooled to 0 degrees. To this, 26 g of potassium t-butoxide was added little by little. After 1 hour, 3- (4-methylcyclohexyl) propanal 32 (0.2077) g was slowly added and stirred for 4 hours. After confirming the reaction by GC, 100 ml of water was added to the system. After the solvent was distilled off, hexane was added to form a hexane solution, which was then washed with water. The solution was dried using anhydrous sodium sulfate, and the solvent was distilled off to obtain 33 g of the desired product as a colorless transparent liquid. Yield 71%. GC purity 95%. M + 224.

<Synthesis 4-7>
Synthesis of ethyl 5- (4-methylcyclohexyl) pentanoate

  In a 1 L autoclave, 33 g of ethyl 5- (4-methylcyclohexyl) -2-pentenoate was dissolved in 300 ml of ethyl acetate, and 3.4 g of 5 wt% palladium / carbon was added thereto. The system was purged with nitrogen and then replaced with hydrogen, the hydrogen pressure was set to 0.4 MPa, and the system was heated to 40 degrees. The mixture was stirred overnight as it was, the system was cooled to room temperature, filtered, and the solvent was distilled off to obtain 32 g of the desired product as a colorless and transparent liquid. Yield 96%. GC purity 97%. M + 226.

<Synthesis 4-8>
Synthesis of 5- (4-methylcyclohexyl) pentanol

  7.4 g of lithium aluminum hydride was suspended in 250 ml of THF in a 2 L four-necked flask purged with nitrogen and cooled to 5 degrees. A solution of 32 g of ethyl 5- (4-methylcyclohexyl) pentanoate dissolved in 100 ml of THF was slowly added dropwise and stirred for 6 hours. After confirming the completion of the reaction by GC, 20 ml of water was added, and then 200 ml of 18% hydrochloric acid was added. After the separation, the aqueous layer was extracted twice with toluene, washed with water together with the previous organic layer, further washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was distilled off to obtain 25 g of the desired product as a pale yellow liquid. Yield 96%. GC purity 99%. M + 184.

<Synthesis 4-9>
Synthesis of 5- (4-methylcyclohexyl) pentyl methanesulfonate

  25 g (0.297) of 5- (4-methylcyclohexyl) pentanol was dissolved in 200 ml of dichloromethane in a nitrogen-substituted 1 L four-necked flask, and 32 g of triethylamine was added and cooled to 0 ° C. 37 g of methanesulfonic acid chloride was slowly added dropwise and stirred for 6 hours. The system was returned to room temperature and 300 ml of water was added. After separation, the organic layer was washed with saturated brine. The solvent was distilled off, and purification was performed using 100 g of silica gel using a mixed solvent of ethyl acetate: heptane (1:10) as the solvent, followed by recrystallization using methanol. As a result, 24 g of the desired product was obtained as a white solid. Got. Yield 67%. GC purity 95.5%. M + 262.

<< Synthesis 5-1 >>
Synthesis of 1,2-difluoro-3- (4-pentylphenyl) -6- (4- (3- (4-propylcyclohexyl) propoxy) phenyl) benzene

In a 500 ml four-necked flask purged with nitrogen, 5.01 g of 4- (2,3-difluoro- (4- (4-pentylphenyl)) phenyl) phenol and 4.19 g of 3- (4-propylcyclohexyl) propyl methanesulfonate And 2.79 g of potassium carbonate were suspended in 60 ml of N, N-dimethylformamide and heated to 100 degrees. After stirring for 6 hours, the system was cooled to room temperature and 1 L of toluene was added. The reaction solution was transferred to a separatory funnel, washed with water, then washed with 12% hydrochloric acid, further washed with a saturated aqueous sodium hydrogen carbonate solution and then with brine. The solvent was distilled off, and the resulting solid was purified using 50 g of silica gel using a toluene: heptane (1: 5) mixed solvent as the solvent, and then recrystallized using ethanol to obtain a white solid. As a result, 5.7 g of the target product was obtained. Yield 77%. GC purity 99.6%. M + 518.
NMR: δ = 0.93 (m, 10H), 1.19 (m, 4H), 1.40 (m, 8H), 1.72 (m, 2H), 1.80 (m, 6H), 2.69 (t, 2H), 4.02 (t, 2H), 7.02 (d, 2H), 7.25 (d, 2H), 7.30 (d, 2H), 7.54 (m, 4H).
Cr 97 SmC 137 SmA 146 N 209 Iso

<< Synthesis 5-2 >>
Synthesis of 1,2-difluoro-3- (4-pentylphenyl) -6- (4- (5- (4-methylcyclohexyl) pentyloxy) phenyl) benzene

In a nitrogen-substituted 500 ml four-necked flask, 4.32 g of 4- (2,3-difluoro- (4- (4-pentylphenyl)) phenyl) phenol and 3.61 g of 5- (4-methylcyclohexyl) pentyl methanesulfonate And 1.94 g of potassium carbonate were suspended in 60 ml of N, N-dimethylformamide and heated to 100 degrees. After stirring for 6 hours, the system was cooled to room temperature and 1 L of toluene was added. The reaction solution was transferred to a separatory funnel, washed with water, then washed with 12% hydrochloric acid, further washed with a saturated aqueous sodium hydrogen carbonate solution and then with brine. The solvent was distilled off, and the resulting solid was purified using 50 g of silica gel using a toluene: heptane (1: 5) mixed solvent as the solvent, and then recrystallized using ethanol to obtain a white solid. As a result, 3.2 g of the target product was obtained. Yield 52%. GC purity 99.3%. M + 518.
NMR: δ = 0.89 (m, 10H), 1.25 (m, 4H), 1.41 (m, 8H), 1.70 (m, 6H), 1.84 (m, 2H), 2.69 (t, 2H), 4.04 (t, 2H), 7.02 (d, 2H), 7.25 (d, 2H), 7.31 (d, 2H), 7.54 (m, 4H).
Cr 87 SmC 116 N 171.5 Iso

<< Synthesis 5-3 >>
Synthesis of 1- (2,3-difluoro-4-pentylphenyl) -4- (4- (3- (4-propylcyclohexyl) propoxy) phenyl) benzene

In a nitrogen-substituted 500 ml four-necked flask, 23.38 g of 4- (4- (2,3-difluoro-4-pentylphenyl) phenyl) phenol and 20.24 g of 3- (4-propylcyclohexyl) propyl methanesulfonate and 10.58 g potassium carbonate was suspended in 100 ml N, N-dimethylformamide and heated to 100 degrees. After stirring for 6 hours, the system was cooled to room temperature and 1 L of toluene was added. The reaction solution was transferred to a separatory funnel, washed with water, then washed with 12% hydrochloric acid, further washed with a saturated aqueous sodium hydrogen carbonate solution and then with brine. The solvent was distilled off, and the resulting solid was purified using 200 g of silica gel using a toluene: heptane (1: 5) mixed solvent as a solvent, and then recrystallized using ethanol to obtain a white solid. As a result, 23.8 g of the target product was obtained. Yield 70%. GC purity 99.2%. M + 518.
NMR: δ = 0.90 (m, 10H), 1.16 (m, 4H), 1.38 (m, 8H), 1.65 (m, 2H), 1.76 (m, 6H), 2.69 (t, 2H), 3.98 (t, 2H), 6.98 (m, 3H), 7.13 (m, 1H), 7.59 (m, 6H).
Cr 118 SmC 161 SmA 210 N 222 Iso

<< Synthesis 5-4 >>
Synthesis of 1- (2,3-difluoro-4-pentylphenyl) -4- (4- (5- (4-methylcyclohexyl) pentyloxy) phenyl) benzene

In a nitrogen-substituted 500 ml four-necked flask, 9.24 g of 4- (4- (2,3-difluoro-4-pentylphenyl) phenyl) phenol and 7.58 g of 3- (4-propylcyclohexyl) propyl methanesulfonate and 7.2 g potassium carbonate was suspended in 100 ml N, N-dimethylformamide and heated to 100 degrees. After stirring for 6 hours, the system was cooled to room temperature and 1 L of toluene was added. The reaction solution was transferred to a separatory funnel, washed with water, then washed with 12% hydrochloric acid, further washed with a saturated aqueous sodium hydrogen carbonate solution and then with brine. The solvent was distilled off, and the resulting solid was purified using 200 g of silica gel using a toluene: heptane (1: 5) mixed solvent as a solvent, and then recrystallized using ethanol to obtain a white solid. As a result, 8.4 g of the target product was obtained. Yield 59%. GC purity 99.8%. M + 518.
NMR: δ = 0.87 (m, 10H), 1.25 (m, 4H), 1.37 (m, 8H), 1.66 (m, 6H), 1.85 (m, 2H), 2.69 (t, 2H), 4.00 (t, 2H), 6.98 (m, 3H), 7.15 (m, 1H), 7.62 (m, 6H).
Cr 75 X 108 SmC 158 SmA 176 N 186 Iso

<Differential scanning calorimetry (1)>
When the differential scanning calorimetry of the obtained liquid crystal compound and the compounds (C1) to (C4) represented by the formulas (C1) to (C4) was performed, the charts shown in FIGS. 1 to 4 were obtained. .

<< Synthesis 6 >>
Synthesis of 2,3-difluoro-4- (4- (4-pentylphenyl) phenyl) phenol

<Synthesis 6-1>
Synthesis of 2,3-difluoro-4-methoxyphenylboric acid

  In a 1 L four-necked flask purged with nitrogen, 102 g of 1,2-difluoro-3-methoxybenzene was dissolved in 300 ml of THF and cooled to -78 degrees. To this, 326 ml of 2.4 M butyllithium hexane solution was added over 1 hour. After 1 hour, 133 g of trimethyl borate dissolved in 130 ml of THF was added dropwise over 1 hour. After 1 hour, the temperature of the system was adjusted to −30 ° C., 160 ml of 36% hydrochloric acid was added, and the mixture was stirred for 2 hours. To the system, 500 ml of ethyl acetate and 200 ml of water were added and stirred, and the organic layer was separated. Furthermore, extraction was performed using 200 ml of ethyl acetate, and the organic layer was combined and washed with 100 ml of saturated brine. After the solution was dried with magnesium sulfate, the solvent was distilled off to obtain 133 g of the desired product as a white solid. Yield 100%.

<Synthesis 6-2>
Synthesis of 2,3-difluoro-1-methoxy-4- (4- (4-pentylphenyl) phenyl) benzene

  Into a nitrogen-substituted 2 L four-necked flask, 133 g of 2,3-difluoro-4-methoxyphenylboric acid, 186.3 g of 1-bromo-4- (4-pentylphenyl) benzene, 622 g of 30% aqueous potassium carbonate solution, N , N-dimethylacetamide 250 ml and toluene 450 ml were mixed. To this, 5.9 g of tetrakistriphenylphosphine palladium (0) complex was added, and the system was brought to reflux temperature and stirred for 20 hours. After confirming the completion of the reaction by GC, the reaction mixture was cooled to room temperature, and 500 ml of 18% hydrochloric acid was added thereto. An additional 500 ml of toluene was added and stirred to separate the organic layer. Subsequently, extraction was performed twice using 200 ml of toluene. The organic layers were combined and washed with 200 ml of water and then with 200 ml of saturated brine. After the solvent was distilled off, purification was performed using 300 g of silica gel using a mixed solvent of ethyl acetate: heptane (1: 5) as the solvent, followed by recrystallization using ethanol and acetone. As a white solid, 178 g The desired product was obtained. Yield 49.2%. GC purity 99.5%. M + 366.

<Synthesis 6-3>
Synthesis of 2,3-difluoro-4- (4- (4-pentylphenyl) phenyl) phenol

  In a 2 L four-necked flask, 128 g of 2,3-difluoro-1-methoxy-4- (4- (4-pentylphenyl) phenyl) benzene was dissolved in 4 L of dichloromethane and cooled to 0 degrees. A solution prepared by dissolving 100 g of boron tribromide in 250 ml of dichloromethane was added dropwise thereto over 1 hour, followed by stirring for 72 hours. 100 ml of water was added to the system and stirred, and the organic layer and the aqueous layer were separated. The organic layer was washed with water, then with a saturated aqueous sodium hydrogen carbonate solution, and further with saturated brine. After the solvent was distilled off, purification was carried out using 300 g of silica gel using a mixed solvent of ethyl acetate: toluene (1:10) as the solvent, followed by recrystallization using heptane. I got a thing. Yield 94.9%. GC purity 97%. M + 352.

<< Synthesis 7 >>
Synthesis of 5-cyclohexylpentyl methanesulfonate

<Synthesis 7-1>
Synthesis of ethoxycarbonylpropyl (triphenyl) phosphonium bromide

  In a nitrogen-substituted 5 L four-necked flask, 136 g of ethyl 4-bromobutanoate and 238 g of triphenylphosphine were dissolved in 1,000 ml of xylene, which was heated to a temperature at which xylene was refluxed and stirred for 4 hours. The system was cooled to room temperature, and the precipitated white crystals were filtered out and dissolved in 300 ml of dichloromethane, and the precipitated crystals were poured into 1 L of hexane and filtered. The crystals were washed with xylene to obtain 301 g of the desired product as a white solid. Yield 97%.

<Synthesis 7-2>
Synthesis of ethyl 5-cyclohexyl-4-butenoate

  301 g of ethoxycarbonylpropyl (triphenyl) phosphonium bromide was suspended in 500 ml of THF in a 2 L four-necked flask purged with nitrogen, and cooled to 0 degrees. To this, 64 g of potassium t-butoxide was added little by little. After 2 hours, a solution of 57 g of cyclohexyl formaldehyde dissolved in 70 ml of THF was added dropwise over 1 hour and stirred overnight. After confirming the reaction by GC, 200 ml of water was added to the system. The organic layer and the aqueous layer were separated, and hexane was added to the aqueous layer for extraction three times. The organic layer was combined, washed with saturated brine three times, and then dried with calcium chloride. Distillation was performed to obtain 74 g of the desired product as a yellow liquid. Yield 69%. GC purity 88%. M + 210.

<Synthesis 7-3>
Synthesis of 5-cyclohexyl-4-penten-1-ol

  16.3 g of lithium aluminum hydride is suspended in 700 ml of THF in a nitrogen-substituted 2 L four-necked flask. The system was cooled to 5 degrees and a solution of 74 g of ethyl 5-cyclohexyl-4-butenoate dissolved in 100 ml of THF was added dropwise over 1 hour. The reaction solution was stirred for 3 hours, and after confirming that the reaction was completed by GC, 60 ml of water was slowly added dropwise. Filtration was performed, and the filtrate was dried over sodium sulfate and distilled. 45 g of the desired product was obtained as a pale yellow liquid. Yield 76%. GC purity 95%. M + 168.

<Synthesis 7-4>
Synthesis of 5-cyclohexylpentan-1-ol

  In a 2 L autoclave, 42 g of 5-cyclohexyl-4-penten-1-ol was dissolved in 300 ml of ethyl acetate, and 5 g of 5 wt% palladium / carbon was added thereto. The system was purged with nitrogen and then replaced with hydrogen, the hydrogen pressure was set to 0.4 MPa, and the system was heated to 40 degrees. The mixture was stirred as it was overnight, the system was cooled to room temperature, filtered, and the solvent was distilled off to obtain 42 g of the objective product as a colorless and transparent liquid. Yield 99%. GC purity 97%. M + 170.

<Synthesis 7-5>
Synthesis of 5-cyclohexylpentyl methanesulfonate

  In a 1 L four-necked flask purged with nitrogen, 36.3 g of 5-cyclohexylpentan-1-ol was dissolved in 200 ml of dichloromethane, and 25.1 g of triethylamine was added, followed by cooling to 0 ° C. 29.0 g of methanesulfonic acid chloride was slowly added dropwise and stirred for 6 hours. The system was returned to room temperature and 300 ml of water was added. After separation, the organic layer was washed with saturated brine. The solvent was distilled off, and purification was performed using 100 g of silica gel using a mixed solvent of dichloromethane: heptane (3: 7) as the solvent, followed by recrystallization using methanol. As a result, 20 g of the target product was obtained as a white liquid. Obtained. Yield 37%. GC purity 95%. M + 248.

<< Synthesis 8-1 >>
Synthesis of 2,3-difluoro-1- (4- (4-pentylphenyl) phenyl) -4- (3- (4-propylcyclohexyl) propoxy) benzene

In a nitrogen-substituted 1 L four-necked flask, 19 g of 2,3-difluoro-4- (4- (4-pentylphenyl) phenyl) phenol and 16.3 g of 3- (4-propylcyclohexyl) propyl methanesulfonate and 11.2 g Of potassium carbonate was suspended in 350 ml of N, N-dimethylacetamide and heated to 100 degrees. After stirring for 6 hours, the system was cooled to room temperature and 1 L of toluene was added. The reaction solution was transferred to a separatory funnel, washed with water, then washed with 12% hydrochloric acid, further washed with a saturated aqueous sodium hydrogen carbonate solution and then with brine. The solvent was distilled off, and the resulting solid was purified using 50 g of silica gel using a toluene: heptane (1: 5) mixed solvent as the solvent, and then recrystallized using ethanol to obtain a white solid. As a result, 20.5 g of the desired product was obtained. Yield 73%. GC purity 99.9%. M + 518.
NMR: δ = 0.88 (m, 10H), 1.16 (m, 4H), 1.37 (m, 8H), 1.66 (m, 2H), 1.76 (m, 4H), 1.85 (m, 2H), 2.65 (t, 2H), 4.05 (t, 2H), 6.79 (m, 1H), 7.12 (m, 1H), 7.25 (m, 2H), 7.56 (m, 4H), 7.64 (m, 2H).
Cr1 77 Cr2 105 SmC 159 N 214 Iso

<< Synthesis 8-2 >>
Synthesis of 2,3-difluoro-1- (4- (4-pentylphenyl) phenyl) -4- (5- (4-methylcyclohexyl) pentyloxy) benzene

In a nitrogen-substituted 500 ml four-necked flask, 8.9 g of 2,3-difluoro-4- (4- (4-pentylphenyl) phenyl) phenol and 7.4 g of 5- (4-methylcyclohexyl) pentyl methanesulfonate and 5.8 g g potassium carbonate was suspended in 120 ml N, N-dimethylacetamide and heated to 80 degrees. After stirring for 6 hours, the system was cooled to room temperature and 1 L of toluene was added. The reaction solution was transferred to a separatory funnel, washed with water, then washed with 12% hydrochloric acid, further washed with a saturated aqueous sodium hydrogen carbonate solution and then with brine. The solvent was distilled off, and the resulting solid was purified using 50 g of silica gel using a toluene: heptane (1: 5) mixed solvent as the solvent, and then recrystallized using ethanol to obtain a white solid. As a result, 8 g of the desired product was obtained. Yield 61%. GC purity 99.5%. M + 518.
NMR: δ = 0.89 (m, 10H), 1.1-1.45 (m, 12H), 1.66 (m, 6H), 1.84 (m, 2H), 2.65 (t, 2H), 4.08 (t, 2H), 6.81 ( t, 1H), 7.13 (m, 1H), 7.26 (m, 2H), 7.56 (m, 4H), 7.58 (d, 2H).
Cr 94 SmC 138 N 178.5 Iso

<< Synthesis 8-3 >>
Synthesis of 2,3-difluoro-1- (4- (4-pentylphenyl) phenyl) -4- (5-cyclohexylpentyloxy) benzene

A nitrogen-substituted 500 ml four-necked flask was charged with 19.3 g 2,3-difluoro-4- (4- (4-pentylphenyl) phenyl) phenol, 16.3 g 5-cyclohexylpentyl methanesulfonate and 7.6 g potassium carbonate. It was suspended in 265 ml of N, N-dimethylacetamide and heated to 85 degrees. After stirring for 6 hours, the system was cooled to room temperature and 1 L of toluene was added. The reaction solution was transferred to a separatory funnel, washed with water, then washed with 12% hydrochloric acid, further washed with a saturated aqueous sodium hydrogen carbonate solution and then with brine. The solvent was distilled off, and the resulting solid was purified using 50 g of silica gel using a toluene: heptane (1: 5) mixed solvent as the solvent, and then recrystallized using ethanol to obtain a white solid. As a result, 15 g of the desired product was obtained. Yield 53%. GC purity 99.5%. M + 504.
NMR: δ = 0.91 (m, 5H), 1.21 (m, 6H), 1.36 (m, 6H), 1.46 (m, 2H), 1.68 (m, 7H), 1.86 (m, 2H), 2.65 (t, 2H), 4.07 (t, 2H), 6.80 (t, 1H), 7.13 (m, 1H), 7.26 (m, 2H), 7.56 (m, 4H), 7.58 (d, 2H).
Cr 100 SmC 136 N 152 Iso

<< Synthesis 8-4 >>
Synthesis of 1,2-difluoro-3- (4-pentylphenyl) -6- (4- (5-cyclohexylpentyloxy) phenyl) benzene

In a 500 ml four-necked flask purged with nitrogen, 6.8 g of 4- (2,3-difluoro- (4- (4-pentylphenyl)) phenyl) phenol, 5.3 g of 5-cyclohexylpentyl methanesulfonate and 3.0 g of carbonic acid Potassium was suspended in 80 ml of N, N-dimethylacetamide and heated to 100 degrees. After stirring for 6 hours, the system was cooled to room temperature and 1 L of toluene was added. The reaction solution was transferred to a separatory funnel, washed with water, then washed with 12% hydrochloric acid, further washed with a saturated aqueous sodium hydrogen carbonate solution and then with brine. The solvent was distilled off, and the resulting solid was purified using 50 g of silica gel using a toluene: heptane (1: 5) mixed solvent as the solvent, and then recrystallized using ethanol to obtain a white solid. As a result, 8 g of the desired product was obtained. Yield 79%. GC purity 99.0%. M + 504.
NMR: δ = 0.94 (m, 5H), 1.24 (m, 6H), 1.39 (m, 8H), 1.72 (m, 7H), 1.84 (m, 2H), 2.69 (t, 2H), 4.04 (t, 2H), 7.02 (d, 2H), 7.25 (d, 2H), 7.30 (m, 2H), 7.54 (m, 4H).
Cr 92 SmC 102 N 139 Iso

<< Synthesis 9 >>
Synthesis of 2,3-difluoro-1- (4- (4-pentylphenyl) phenyl) -4- (5-cyclohexylmethyloxy) benzene

Synthesis was performed in the same manner as the compounds represented by the formulas (C5) to (C7) shown above, and 20.5 g of the target product was obtained as a white solid. GC purity 98.8%. M + 504.
NMR: δ = 0.90 (m, 8H), 1.09 (m, 2H), 1.21-1.37 (m, 13H), 1.66 (m, 2H), 1.82 (m, 3H), 1.93 (m, 2H), 2.65 ( t, 2H), 3.86 (d, 2H), 6.79 (m, 1H), 7.11 (m, 1H), 7.25 (m, 2H), 7.55 (m, 4H), 7.64 (d, 2H).
Cr 105 SmC 174 SmA 207 N 244 Iso

<< Synthesis 10 >>
Synthesis of 1,2-difluoro-3- (4-pentylphenyl) -6- (4- (5-cyclohexylbutyloxy) phenyl) benzene

Synthesis was performed in the same manner as the compounds represented by the formulas (C1), (C2), and (C8), and 7.3 g of the target product was obtained as a white solid. GC purity 99.5%. M + 504.
NMR: δ = 0.87 (m, 10H), 1.10 (m, 1H), 1.27 (m, 5H), 1.37 (m, 4H), 1.50 (m, 2H), 1.70 (m, 2H), 1.75 (m, 6H), 2.66 (t, 2H), 4.01 (d, 2H), 6.99 (d, 2H), 7.25 (m, 4H), 7.51 (m, 4H).
Cr 74 SmC 80 N 136 Iso

<Differential scanning calorimetry (2)>
Differential scanning calorimetry of the obtained liquid crystal compound, the compounds (C5) to (C8), (C11) and (C12) represented by the formulas (C5) to (C8), (C11) and (C12). As a result, charts shown in FIGS. 5 to 10 were obtained.

<< Physical property evaluation >>
In order to evaluate the physical properties of each synthesized compound, the comparative compounds (REF1 to REF3) were prepared.

<< Physical property evaluation of compounds C5 to C7, C10 to C11 >>
Similarly to compounds C5 to C7 and C11, compound C10 shown in the following table was synthesized. The purity of each compound shown in the following table was determined by gas chromatography (GC purity). The upper limit temperature of the phase sequence of each compound was determined by differential scanning calorimetry and observation of the liquid crystal phase with a polarizing microscope equipped with a temperature variable device.

A compound (REF1) of a comparative example similar to the terphenyl structure of compounds C5 to C7 and compounds C10 to C11 was synthesized, and the upper limit temperature (phase transition temperature) of the phase series was measured. The upper limit temperature of the SmC phase of the compound of the comparative example (REF1) was 144 ° C.
When the upper limit temperature of the SmC phase of each of the compounds C5 to C7 and C10 to C11 is higher based on the upper limit temperature of the compound (REF1), the compound of the present invention has an effect of increasing the upper limit temperature of the SmC phase. Evaluated that there was. In Table 1, the compound having the effect of increasing the maximum temperature of the SmC phase (first increasing effect) is indicated by “◯”.
Furthermore, when 50 parts by weight of the compound of the present invention is added to 50 parts by weight of the standard compound (REF2), when the temperature rises from the upper limit temperature (95 ° C.) of the SmC phase at which the compound (REF2) is expressed, the present invention It was evaluated that this compound has an effect of increasing the maximum temperature of the SmC phase. In Table 1, the compounds having the effect of increasing the maximum temperature of the SmC phase (second increasing effect) are indicated by “◎”.
In addition, the temperature range of the SmC phase that is expressed when 50 parts by weight of the compound of the present invention is added to 50 parts by weight of the compound (REF2) is the temperature range of the SmC phase that is expressed by the compound (REF2) (46.5 ° C.). If it is wider, it was evaluated that there was an effect of expanding the temperature width of the SmC phase. In Table 1, the compound having the effect of expanding the temperature range of the SmC phase is indicated by “◯”.
In order to increase the tilt angle of the SmC phase, the phase sequence of the liquid crystal is the I phase-N phase-SmC phase (INC phase sequence) from the high temperature side, the I phase-N phase-SmA phase-SmC phase. More preferable than (INAC phase series). For this reason, when it was a compound which expresses an INC phase series, it evaluated that it was a compound which has the expansion effect of the inclination angle of a SmC phase.

<< Evaluation of physical properties of compounds C1 to C2, C8, C12, C14 >>
Compound C14 shown in the following table was synthesized in the same manner as compounds C1 to C2, C8, and C12. The purity of each compound obtained at the synthesis scale (weight) shown in the following table was determined by gas chromatography (GC purity). The upper limit temperature of the phase sequence of each compound was determined by differential scanning calorimetry and observation of the liquid crystal phase with a polarizing microscope equipped with a temperature variable device.

A comparative compound (REF2) similar to the terphenyl structure of compounds C1-C2, C8, C12 and C14 was synthesized, and the upper limit temperature (phase transition temperature) of the phase series was measured. The upper limit temperature of the SmC phase of the compound of the comparative example (REF2) was 95 ° C.
When the upper limit temperature of the SmC phase of each of the compounds C1 to C2, C8, C12, and C14 is higher with respect to the upper limit temperature of the compound (REF2), the compound has an effect of increasing the upper limit temperature of SmC. evaluated. In Table 2, the compound having the effect of increasing the maximum temperature of the SmC phase (first increasing effect) is indicated by “◯”.
Furthermore, when 50 parts by weight of the compound of the present invention is added to 50 parts by weight of the standard compound (REF2), when the temperature rises from the upper limit temperature (95 ° C.) of the SmC phase at which the compound (REF2) is expressed, the present invention It was evaluated that this compound has an effect of increasing the maximum temperature of the SmC phase. In Table 2, the compound having the effect of increasing the maximum temperature of the SmC phase (second increasing effect) is indicated by “◎”.
In addition, the temperature range of the SmC phase that appears when 50 parts by weight of the compound of the present invention is added to 50 parts by weight of the standard compound (REF2) is equal to the temperature range of the SmC phase that the compound (REF2) expresses (46.5). In the case of wider than (° C.), it was evaluated that there was an effect of expanding the temperature width of the SmC phase. In Table 2, the compound having the effect of expanding the temperature range of the SmC phase is indicated by “◯”.
In order to increase the tilt angle of the SmC phase, the phase sequence of the liquid crystal is the I phase-N phase-SmC phase (INC phase sequence) from the high temperature side, the I phase-N phase-SmA phase-SmC phase. More preferable than (INAC phase series). For this reason, when it was a compound which expresses an INC phase series, it evaluated that it was a compound which has the expansion effect of the inclination angle of a SmC phase.

<< Physical property evaluation of compounds C3 to C4, C18 >>
Similarly to compounds C3 to C4, compound C18 shown in the following table was synthesized. The purity of each compound obtained at the synthesis scale (weight) shown in the following table was determined by gas chromatography (GC purity). The upper limit temperature of the phase sequence of each compound was determined by differential scanning calorimetry and observation of the liquid crystal phase with a polarizing microscope equipped with a temperature variable device.

A comparative compound (REF3) similar to the terphenyl structure of compounds C3, C4 and C18 was synthesized, and the upper limit temperature (phase transition temperature) of the phase series was measured. The upper limit temperature of the SmC phase of the compound of the comparative example (REF3) was 155.5 ° C.
When the upper limit temperature of the SmC phase of each of the compounds C3 to C4 and C18 was higher with reference to the upper limit temperature of this compound (REF3), the compound was evaluated as having an effect of increasing the upper limit temperature of the SmC phase. In Table 3, the compounds having the effect of increasing the maximum temperature of the SmC phase (first increasing effect) are indicated by “◯”.
In order to increase the tilt angle of the SmC phase, the phase sequence of the liquid crystal is the I phase-N phase-SmC phase (INC phase sequence) from the high temperature side, the I phase-N phase-SmA phase-SmC phase. More preferable than (INAC phase series). For this reason, when it was a compound which expresses an INC phase series, it evaluated that it was a compound which has the expansion effect of the inclination angle of a SmC phase.

  From the above results, the compound of the present invention has a bulky group represented by Y in the general formula (i) in addition to the terphenyl structure of the compound of the comparative example, thereby increasing the maximum temperature of the SmC phase. It is understood that it is easy to increase. In the compound of the present invention, the length of the linking group connecting the terphenyl structure and the bulky group is made longer than that of the methylene group, so that the effect of increasing the temperature range of the SmC phase and / or the increase of the tilt angle of the SmC phase. It turns out that an effect becomes easy to be acquired.

<< Liquid crystal composition >>
When each compound was mixed in the ratio shown in Table 4 to prepare a liquid crystal composition, a ferroelectric liquid crystal composition in which each transition temperature of the phase sequence showed the following values was obtained.
Crystal-SmC * phase transition temperature: room temperature or less SmC * phase-N * phase transition temperature: 97.8 ° C
N * phase-I phase transition temperature: 141.8 ° C.

  When the liquid crystal display element was produced by injecting the ferroelectric liquid crystal composition into a glass cell, a liquid crystal display element having excellent display characteristics was obtained.

  The configurations and combinations thereof in the embodiments described above are examples, and the addition, omission, replacement, and other modifications of the configurations can be made without departing from the spirit of the present invention. Further, the present invention is not limited by each embodiment, and is limited only by the scope of the claims.

  The compound according to the present invention is widely applicable in the field of liquid crystal displays.

Claims (7)

Compound represented by the following general formula (i-1).
[Wherein, R represents a hydrogen atom, an alkyl group or an alkoxy group having 1 to 9 carbon atoms having 1 to 10 carbon atoms, m represents an integer of 2 to 10, n represents an integer of 0. ] Compound represented by the following general formula (i-2).
[In formula, R represents a hydrogen atom, a C1-C10 alkyl group, or a C1-C9 alkoxy group, m represents the integer of 1-10, n represents the integer of 0-10. ] Compound represented by the following general formula (i-3).
[In formula, R represents a hydrogen atom, a C1-C10 alkyl group, or a C1-C9 alkoxy group, m represents the integer of 1-10, n represents the integer of 0-10. ] The compound according to claim 1, wherein m represents an integer of 3 to 10. The liquid crystal composition containing the compound as described in any one of Claims 1-4 . 6. The liquid crystal composition according to claim 5 , which is ferroelectric. Display element using the liquid crystal composition according to claim 5 or 6.