JP6085912B2 - Compound, liquid crystal composition, and liquid crystal display device - Google Patents

Description

  The present invention relates to a compound, a liquid crystal composition, and a liquid crystal display element.

  Liquid crystal display elements are used in various measuring instruments, automobile panels, word processors, electronic notebooks, printers, computers, televisions, watches, advertisement display boards, as well as watches and calculators. Typical liquid crystal display methods include TN (twisted nematic) type, STN (super twisted nematic) type, vertical alignment type using TFT (thin film transistor), and IPS (in-plane switching) type. Etc. The liquid crystal composition used in these liquid crystal display elements is stable against external factors such as moisture, air, heat, light, etc., and exhibits a liquid crystal phase in the widest possible temperature range centering on room temperature, and has low viscosity. It is required to be. Furthermore, the liquid crystal composition is composed of several to several tens of kinds of compounds in order to obtain the optimum dielectric anisotropy (Δε) or refractive index anisotropy (Δn) for each display element. Has been.

Particularly in recent years, a fast response liquid crystal composition has been demanded. Various methods are conceivable for achieving the desired physical properties, but an effective means is to reduce the viscosity of the liquid crystal composition. In order to reduce the viscosity of the liquid crystal composition, it is extremely effective to add a compound having a low viscosity (η).
A conventionally proposed compound having low viscosity is a so-called straight ring structure in which a plurality of ring structures such as a benzene ring and a cyclohexane ring are linked by a single bond (see, for example, Patent Document 1). However, in order to further improve the liquid crystal characteristics, there is a demand for the development of a compound having a lower viscosity than conventional straight ring compounds. Furthermore, the compound is also required to have excellent compatibility with the liquid crystal composition.

US Pat. No. 4,620,938

  The present invention has been made in view of the above circumstances, and has a lower viscosity than conventional straight-ring compounds and excellent compatibility with liquid crystal compositions, and liquid crystal compositions and liquid crystal displays using the compounds It is an object to provide an element.

  In order to solve the above-mentioned problems, the present inventors have studied various kinds of ring linking groups, and found that a compound having a specific linking group and a partial structure (2-fluorophenyloxy structure) can solve the above-mentioned problems. The present invention has been completed. That is, this invention provides the compound represented by following General formula (1).

（式中、Ｒ^１及びＲ^２は各々独立して水素原子、炭素原子数１から１５のアルキル基又は炭素原子数２から１５のアルケニル基を表し、Ｒ^１及びＲ^２中に存在する１個の−ＣＨ_２−又は隣接していない２個以上の−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−又は−ＣＯ−により置き換えられても良く、Ｒ^１及びＲ^２中に存在する１個の水素原子又は２個以上の水素原子はフッ素原子により置き換えられても良く、
ｍは０、１、２又は３を表し、ｎは１、２又は３を表し、
Ａ^１及びＡ^２は各々独立して、
（ａ） トランス−１，４−シクロへキシレン基（この基中に存在する１個の−ＣＨ_２−又は隣接していない２個以上の−ＣＨ_２−は−Ｏ−、−ＮＨ−又は−Ｓ−に置き換えられても良い。）、
（ｂ） １，４−フェニレン基（この基中に存在する１個の−ＣＨ＝又は隣接していない２個以上の−ＣＨ＝は−Ｎ＝に置き換えられても良い。）及び、
（ｃ） １，４−シクロヘキセニレン基、１，４−ビシクロ［２．２．２］オクタン−１，４−ジイル基、ナフタレン−２，６−ジイル基、１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基及びデカヒドロナフタレン−２，６−ジイル基
からなる群より選ばれる基を表し、
上記の基（ａ）、基（ｂ）又は基（ｃ）に含まれる水素原子は各々独立して炭素原子数１〜５のアルキル基、炭素原子数１〜５のアルコキシ基、シアノ基、ハロゲン、トリフルオロメチル基又はトリフルオロメトキシ基で置換されていても良いが、Ａ^１が複数存在する場合は、各Ａ^１は同一でも良く異なっていても良く、Ａ^２が複数存在する場合は、各Ａ^２は同一でも良く異なっていても良く、
Ｚ^１及びＺ^２は各々独立して−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ_２ＣＨ_２−、−ＣＦ_２ＣＦ_２−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−、−Ｃ≡Ｃ−又は単結合を表し、Ｚ^１が複数存在する場合は、各Ｚ^１は同一でも良く異なっていても良く、Ｚ^２が複数存在する場合は、各Ｚ^２は同一でも良く異なっていても良く、
Ｙ^１は水素原子、フッ素原子又は塩素原子を表す。）

(Wherein R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms, ^one existing in R ¹ and R ² ) of -CH ₂ - or nonadjacent two or more -CH ₂ - is -O -, - S -, - COO -, - OCO- or -CO- may be replaced by, ^{R 1} and ^{R 2} One hydrogen atom or two or more hydrogen atoms present therein may be replaced by a fluorine atom,
m represents 0, 1, 2 or 3; n represents 1, 2 or 3;
A ¹ and A ² are each independently
(A) trans-1,4-cyclohexylene group (one —CH ₂ — present in this group or two or more non-adjacent —CH ₂ — represents —O—, —NH—, or — May be replaced by S-).
(B) a 1,4-phenylene group (one —CH═ present in the group or two or more non-adjacent —CH═ may be replaced by —N═);
(C) 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octane-1,4-diyl group, naphthalene-2,6-diyl group, 1,2,3,4- Represents a group selected from the group consisting of a tetrahydronaphthalene-2,6-diyl group and a decahydronaphthalene-2,6-diyl group;
The hydrogen atoms contained in the group (a), group (b) or group (c) are each independently an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a cyano group, a halogen atom. , May be substituted with a trifluoromethyl group or a trifluoromethoxy group, but when a plurality of A ¹ are present, each A ¹ may be the same or different, and when a plurality of A ² are present, Each A ² may be the same or different,
Z ¹ and Z ² are each independently —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO—, —CH ₂ CH ₂ —, —CF _{2. CF 2 -, - CH = CH} -, - CF = CF -, - C≡C- or a single bond, ^{if Z 1} there are a plurality, each ^{Z 1} may be different may be the same, Z ^{2 If} there are multiple, each Z ² may be different may be the same,
Y ¹ represents a hydrogen atom, a fluorine atom or a chlorine atom. )

  The present invention also provides a liquid crystal composition containing one or more compounds represented by the general formula (1). Furthermore, the present invention provides a liquid crystal display device using the liquid crystal composition.

Since the compound of the present invention has a lower viscosity than a conventional straight ring compound, when used as a material for a liquid crystal composition, the viscosity of the liquid crystal composition can be lowered as compared with the conventional liquid crystal composition. The driving voltage can be lowered. Moreover, since the compound of this invention is excellent in compatibility with a liquid crystal composition, the liquid crystal composition containing the compound shows a uniform nematic liquid crystal phase.
The liquid crystal composition of the present invention is excellent in storability because precipitation of the contained compound hardly occurs. In addition, since the liquid crystal composition of the present invention has a low viscosity, the liquid crystal display element of the present invention composed of this liquid crystal composition is excellent in high-speed response and can be driven at a low voltage.

Hereinafter, although this invention is demonstrated concretely, this invention is not limited to this.
"Compound"
In general formula (1), R ¹ and R ² each independently represents a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms, and is present in R ¹ and R ² one -CH ₂ that - or nonadjacent two or more -CH ₂ - is -O -, - S -, - COO -, - OCO- or -CO- by may be substituted.

At least one of R ¹ and R ² is preferably an alkyl group or an alkenyl group. The number of carbon atoms of the alkyl group is preferably 10 as the upper limit, preferably 8, 6 is preferable, 5 is preferable, 1 is preferable as the lower limit, and 2 is preferable. Further, -CH ₂ - may be an alkoxy group substituted to the -O-. The alkyl group may be linear or branched, but is preferably linear. Specifically, a methyl group, a methoxy group, an ethyl group, an ethoxy group, an n-propyl group, an n-propoxy group, an n-butyl group, an n-butoxy group, an n-pentyl group, and an n-pentyloxy group. It is preferable. Of these, R ¹ is more preferably a methyl group, an ethyl group or an n-propyl group, and R ² is more preferably a methyl group, an ethyl group, an n-propyl group or an n-butyl group.

The number of carbon atoms of the alkenyl group is preferably 10 as the upper limit, preferably 8, 8, 6 is preferable, and 2 is preferable as the lower limit. Alternatively, an alkenyloxy group in which —CH ₂ — is substituted with —O— may be used. The alkenyl group may be linear or branched, but is preferably linear. Specifically, a vinyl group, 1-propenyl group, 2-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-pentenyl group, 2-pentenyl group, 3-pentenyl group or 4- A pentenyl group is preferred, and a vinyl group, 1-butenyl group, 3-butenyl group, 1-pentenyl group or 3-pentenyl group is more preferred.

^One hydrogen atom or two or more hydrogen atoms present in R ¹ and R ² may be replaced by a fluorine atom.

In general formula (1), m represents 0, 1, 2, or 3, and is preferably 1, 2, or 3, more preferably 1 or 2.
In the general formula (1), n represents 1, 2 or 3, preferably 1 or 2, and more preferably 1.
In general formula (1), m + n is preferably 1 to 4, more preferably 2 to 4, and still more preferably 2 or 3.

In general formula (1), A ¹ and A ² are each independently
(A) trans-1,4-cyclohexylene group,
(B) a 1,4-phenylene group and
(C) 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octane-1,4-diyl group, naphthalene-2,6-diyl group, 1,2,3,4- It represents a group selected from the group consisting of a tetrahydronaphthalene-2,6-diyl group and a decahydronaphthalene-2,6-diyl group.

A ¹ and A ² are preferably each independently the group (a) or the group (b). A ¹ is more preferably the group (a). When A ¹ is the group (a), the viscosity of the compound can be further reduced.

It said group (a) 1 one -CH present in ₂ - or nonadjacent two or more _-CH 2 - may, -O -, - NH- or -S- to be replaced.
One —CH═ present in the group (b) or two or more non-adjacent —CH═ may be replaced by —N═.

  The hydrogen atoms contained in the group (a), group (b) or group (c) are each independently an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a cyano group, a halogen atom. , May be substituted with a trifluoromethyl group or a trifluoromethoxy group.

The number of carbon atoms of the alkyl group is preferably 1 to 5, more preferably 1 to 4, and still more preferably 1 to 3. The alkyl group may be linear or branched, but is preferably linear. Suitable alkyl groups include the alkyl groups exemplified for R ¹ above.

  The number of carbon atoms of the alkoxy group is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2. The alkoxy group may be linear or branched, but is preferably linear. Specifically, methoxy group, ethoxy group, n-propyloxy group, n-butyloxy group, n-pentyloxy group, 1-propen-1-yloxy group, allyloxy group, 1-buten-1-yloxy group, etc. Can be mentioned. Of these, a methoxy group, an ethoxy group, a propoxy group or an n-butoxy group is preferable, and a methoxy group or an ethoxy group is more preferable.

In the general formula (1), when a plurality of A ¹ are present, each A ¹ may be the same or different. In the general formula (1), when a plurality of A ² are present, each A ² may be the same or different.

In the general formula (1), Z ¹ and Z ² are each independently —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO—, —CH. ₂ CH ₂ —, —CF ₂ CF ₂ —, —CH═CH—, —CF═CF—, —C≡C— or a single bond. Among these, Z ¹ and Z ² may each independently be —CF ₂ O—, —OCF ₂ —, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ — or a single bond. _{preferably, -CH 2 CH 2 -, -} CH 2 O -, - OCH 2 - or more preferably a single bond, -OCH ₂ - is more preferably or a single bond, is a single bond, especially preferable.
In the general formula (1), when a plurality of Z ¹ are present, each Z ¹ may be the same or different. In the general formula (1), when a plurality of Z ² are present, each Z ² may be the same or different.

In General Formula (1), Y ¹ represents a hydrogen atom, a fluorine atom or a chlorine atom, and is preferably a fluorine atom.
Note that —O—O—, —O—S—, and —S—S— are not preferable as the structure in the compound represented by the general formula (1) because they are unstable.

  The compound of the present invention is preferably a compound represented by the following general formula (1-1).

In General Formula (1-1), R ¹ , R ² , A ¹ , Z ¹ , A ² , Z ² , n, and Y ¹ are the same as those in General Formula (1).
In the general formula (1-1), ^{A 3} represents any of the following structures (a-1) of (a-5).

［前記構造（ａ−１）中、シクロヘキサン環の１つ又は２つ以上のＣＨ_２基は酸素原子で置換されていてもよく、前記構造（ａ−２）〜（ａ−５）中ベンゼン環の１つ又は２つ以上のＣＨ基は窒素原子で置換されていてもよく、また、前記構造（ａ−１）〜（ａ−５）中の１つ又は２つ以上の水素原子はＣｌ、ＣＦ_３又はＯＣＦ_３で置換されていてもよい。］

[In the structure (a-1), one or more CH ₂ groups of the cyclohexane ring may be substituted with an oxygen atom, and the benzene ring in the structures (a-2) to (a-5) One or two or more CH groups of the above may be substituted with a nitrogen atom, and one or two or more hydrogen atoms in the structures (a-1) to (a-5) are Cl, It may be substituted with CF ₃ or OCF ₃ . ]

A ³ is preferably a trans-1,4-cyclohexylene group or a 1,4-phenylene group, and more preferably a trans-1,4-cyclohexylene group. When A ³ is a trans-1,4-cyclohexylene group, the viscosity of the compound can be further reduced.
In general formula (1-1), the plurality of Z ¹ may be the same or different. Z ¹ bonded to A ³ is preferably a single bond. When the Z ¹ is a single bond, the rigidity of the compound of the present invention is improved, and the viscosity can be further reduced.

In general formula (1-1), m ′ represents 0, 1 or 2, and is preferably 0 or 1. When m ′ is 0 or 1, the compatibility of the compound of the present invention is improved, and the above-described storage stability can be further improved.
In general formula (1-1), m ′ + n is preferably 1 to 3, and more preferably 1 or 2.

  The compound of the present invention is preferably a compound represented by the following general formula (1-2).

In general formula (1-2), R ¹ , R ² , A ¹ , Z ¹ , A ² , Z ² , and Y ¹ are the same as those in general formula (1). M ′ and A ³ are the same as those in the general formula (1-1).
In the general formula (1-2), A ⁴ is any one of the structures (a-1) to (a-5), and among these, a trans-1,4-cyclohexylene group or 1,4- A phenylene group is preferred. When A ⁴ is any one of these groups, moderate rigidity and freedom are imparted to the compound of the present invention, and the aforementioned viscosity can be further reduced.

In the general formula (1-2), a plurality of Z ¹ may be the same or may be different. Z ¹ bonded to A ³ is preferably a single bond. When the Z ¹ is a single bond, the rigidity of the compound of the present invention is improved, and the viscosity can be further reduced.
In the general formula (1-2), to the plurality of Z ² may be the same or may be different. Z ² bonded to A ⁴ is preferably a single bond. When the Z ² is a single bond, the rigidity of the compound of the present invention is improved, and the aforementioned viscosity can be further reduced.

In general formula (1-2), n ′ represents 0, 1 or 2, and is preferably 0 or 1. When n ′ is 0 or 1, the compatibility of the compound of the present invention is improved, and the above-described storage stability can be further improved.
In general formula (1-2), m ′ + n ′ is preferably 0 to 2, and more preferably 1 or 2.

  The compound of the present invention is more preferably a compound represented by the following general formula (1-3).

Each symbol in the general formula (1-3) is the same as the symbol in the general formula (1-2). By bonding A ⁴ and R ² without the above-described Z ² (by Z ² being a single bond), the above-described viscosity can be further reduced and the above-described compatibility can be further improved.

  The compound of the present invention is more preferably a compound represented by the following general formula (1-4).

Each symbol in the general formula (1-4) is the same as the symbol in the general formula (1-2). However, m ″ is 0 or 1. The plurality of A ³ may be the same or different.
If A ³ is plural, (by the Z ¹ and Z ² is a single bond) by the plurality of A ³ is attached without using the Z ^1, it improves the rigidity of the compounds of the present invention, The aforementioned viscosity can be further reduced, and the aforementioned compatibility can be further improved.

<Liquid crystal composition>
The liquid crystal composition of the present invention contains one or more of the compounds according to the present invention described above.
The liquid crystal composition of the present invention preferably contains a conventionally known liquid crystal material in addition to the compound.

<Liquid crystal material>
There are various liquid crystal materials such as nematic, smectic, discotic, cholesteric, etc., and conventionally known biphenyl, terphenyl, phenylcyclohexane, phenylbicyclohexane, biphenylylcyclohexane, benzoic acid phenyl ester, cyclohexanecarboxylic acid phenyl ester, biphenyl. Carboxylic acid phenyl ester, cyclohexyl benzoic acid phenyl ester, cyclohexyl benzoic acid cyclohexyl ester, phenylpyrimidine, biphenylylpyrimidine, 2,5-diphenylpyrimidine, phenyldioxane, biphenylyldioxane, diphenylacetylene (also known as tolan), 1-phenyl-2 -Cyclohexylethane, 1-phenyl-2-biphenylylethane, 1-cyclohexyl-2-biphenylylethane , Cyanophenyl ester, cyanobiphenyl ester, alkyl cyano biphenyl, alkyl cyano terphenyl, azoxy benzene, etc. as the skeleton, alkyl group, alkoxy group, halogen atom (fluorine, chlorine, bromine etc.), cyano group, ether group, Examples thereof include a low-molecular liquid crystal compound which may have a substituent such as an ester group or an aryl group, a cholesterol derivative, a triphenylene derivative, a lyotropic liquid crystal, or a liquid crystal polymer such as aromatic polyester or aromatic polyamide. As the liquid crystal material, either a positive or negative dielectric anisotropy can be used, and a liquid crystal compound having a positive dielectric anisotropy and a negative liquid crystal compound can be used in combination.

  When a liquid crystal material is sandwiched between two substrates to align the liquid crystal substantially parallel to the substrate and apply an electric field substantially parallel to the substrate to use it as an optical element or display element (for a horizontal alignment type liquid crystal cell). Case), the liquid crystal material preferably has a positive dielectric anisotropy. As a thing with positive dielectric anisotropy, it is preferable to contain the compound represented, for example by the following general formula (III'a), general formula (III'b), or general formula (III'c).

(Wherein R ⁵ represents an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, or a hydrogen atom, and the alkyl group or alkenyl group is unsubstituted or has one substituent. Or may have two or more fluorine atoms, chlorine atoms, methyl groups or trifluoromethyl groups, and one or more methylene groups present in the alkyl group or alkenyl group are substituted with —CO—. And may be substituted with —S—, —O—, —OCOO—, —OCO— or —COO— as those in which oxygen atoms are not directly bonded to each other,
C ¹ , C ² and C ³ are each independently
(Ca) trans-1,4-cyclohexylene group (one methylene group present in this group or two or more methylene groups not adjacent to each other are replaced by -O- or -S-) )
(Cb) 1,4-phenylene group (one —CH═ present in this group or two or more —CH═ not adjacent to each other may be replaced by a nitrogen atom); and
(Cc) 1,4-cyclohexenylene group, 1,4-bicyclo (2.2.2) octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, 1,2 , 3,4-tetrahydronaphthalene-2,6-diyl group and decahydronaphthalene-2,6-diyl group, the groups (Ca) and (Cb) above. Alternatively, the group (Cc) may be substituted with a cyano group, a fluorine atom or a chlorine atom,
K ¹ , K ² and K ³ are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —OCF ₂ —, —CF _2. O—, —OCO—, —COO—, —CH═CH— or —C≡C—
X ¹ , X ³ , X ⁴ , X ⁵ and X ⁶ each independently represent a hydrogen atom or a fluorine atom,
p and q each independently represent 0, 1 or 2, but the sum of p and q is 2 or less,
X ² has the same meaning as hydrogen atom, fluorine atom, chlorine atom, cyano group, trifluoromethyl group, fluoromethoxy group, difluoromethoxy group, trifluoromethoxy group, 2,2,2-trifluoroethyl group or R ^5. Represents. )

In general formula (III′a), general formula (III′b), and general formula (III′c), R ⁵ represents a linear alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms. It is more preferable that it represents a linear alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and a linear alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 6 carbon atoms. It is particularly preferable to represent a group, and an alkenyl group more preferably represents a structure of formulas (a) to (e).

(The structural formula shall be connected to the ring at the right end.)

K ¹ , K ² and K ³ represent —COO—, —OCO—, —CH ₂ CH ₂ —, —CH═CH—, —C≡C—, — (CH ₂ ) ₄ — or a single bond. Is more preferable, —CH ₂ CH ₂ —, —C≡C— or a single bond is more preferable, —CH ₂ CH ₂ — or a single bond is particularly preferable, and K ¹ , K ² or K ³ is When two or more are present, at least one is preferably a single bond.
p and q preferably represent 0 or 1.
C ¹ , C ² and C ³ are each independently a trans-1,4-cyclohexylene group, 1,4-phenylene group, 3-fluoro-1,4-phenylene group or 3,5-difluoro-1, It preferably represents a 4-phenylene group, more preferably represents a trans-1,4-cyclohexylene group or a 1,4-phenylene group, and particularly preferably represents a trans-1,4-cyclohexylene group. .
X ² preferably represents a fluorine atom, a cyano group, a trifluoromethyl group, a fluoromethoxy group, a difluoromethoxy group or a trifluoromethoxy group, and particularly preferably represents a fluorine atom.

  In the liquid crystal composition, the general formula (II ′) having a small absolute value of Δε

Wherein R ³ and R ⁴ each independently represents an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms or a hydrogen atom, and the alkyl group or alkenyl group is unsubstituted. One or two or more methylenes present in the alkyl group or alkenyl group which may have one or two or more fluorine atoms, chlorine atoms, methyl groups or trifluoromethyl groups as substituents The group may be substituted with -CO-, and may be substituted with -S-, -O-, -OCOO-, -OCO- or -COO-, as oxygen atoms are not directly bonded to each other. well,
B ¹ , B ² and B ³ are each independently (B-a) trans-1,4-cyclohexylene group (one methylene group present in this group or two or more methylenes not adjacent to each other). The group may be replaced by -O- or -S-),
(Bb) 1,4-phenylene group (one —CH═ present in this group or two or more —CH═ which are not adjacent to each other may be replaced by a nitrogen atom), and (B -C) 1,4-cyclohexenylene group, 1,4-bicyclo (2.2.2) octylene group, piperidine-1,4-diyl group, naphthalene-2,6-diyl group, decahydronaphthalene-2 , 6-diyl group and 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, a group selected from the group consisting of the group (Ba), group (Bb) or group (Bc) may each be substituted with a cyano group, a fluorine atom or a chlorine atom,
o represents 0, 1 or 2;
L ¹ and L ² are each independently a single bond, —COO—, —OCO—, —CH ₂ CH ₂ —, —CH═CH—, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH _2. O— or —C≡C— is represented, and when there are a plurality of L ² and B ³ , they may be the same or different. It is preferable to contain the compound represented by this.

In general formula (II ′), R ³ and R ⁴ preferably represent an unsubstituted linear alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms, and unsubstituted linear carbon. More preferably, it represents an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and represents an unsubstituted linear alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 6 carbon atoms. Particularly preferred are alkenyl groups, and the structures represented by the above formulas (a) to (e) are more preferred. R ³ and R ⁴ may be the same or different, but it is more preferable that R ³ and R ⁴ in the same molecule are different.
L ¹ and L ² preferably represent —COO—, —OCO—, —CH ₂ CH ₂ —, —CH═CH—, —C≡C—, — (CH ₂ ) ₄ — or a single bond, _{-CH 2 CH 2 -, - CH} = CH -, - C≡C- or more preferably represents a single bond, _-CH 2 CH ₂ -, especially preferably represents an or a single bond, is ^{L 1} and ^{L 2} When there are a plurality of them, at least one preferably represents a single bond.
o preferably represents 0 or 1.
B ¹ , B ² and B ³ are each independently a trans-1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4- It preferably represents a phenylene group or a 3,5-difluoro-1,4-phenylene group, more preferably represents a trans-1,4-cyclohexylene group or a 1,4-phenylene group, and B ¹ , B ² and At least one of B ³ preferably represents a trans-1,4-cyclohexylene group.

In general formula (II ′), R ³ and R ⁴ preferably represent an unsubstituted (unsubstituted) linear alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms. It is more preferable to represent a linear alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and an unsubstituted linear alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 6 carbon atoms. In particular, the alkenyl group is more preferably a structure represented by the above formulas (a) to (e). R ³ and R ⁴ may be the same or different, but it is more preferable that R ³ and R ⁴ in the same molecule are different.
L ¹ and L ² preferably represent —COO—, —OCO—, —CH ₂ CH ₂ —, —CH═CH—, —C≡C—, — (CH ₂ ) ₄ — or a single bond, _{-CH 2 CH 2 -, - CH} = CH -, - C≡C- or more preferably represents a single bond, _-CH 2 CH ₂ -, especially preferably represents an or a single bond, is ^{L 1} and ^{L 2} When there are a plurality of them, at least one preferably represents a single bond.
o preferably represents 0 or 1.
B ¹ , B ² and B ³ are each independently a trans-1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4- It preferably represents a phenylene group or a 3,5-difluoro-1,4-phenylene group, more preferably represents a trans-1,4-cyclohexylene group or a 1,4-phenylene group, and B ¹ , B ² and At least one of B ³ preferably represents a trans-1,4-cyclohexylene group.

  When the liquid crystal composition is applied to a vertical alignment type liquid crystal cell, it is preferable to use a liquid crystal having negative dielectric anisotropy. In this case, the compound according to the present invention can be used, for example, by containing it in a dicyanobenzene liquid crystal, a pyridazine liquid crystal, a Schiff base liquid crystal, an azoxy liquid crystal, a naphthalene liquid crystal, a biphenyl liquid crystal, or a phenylcyclohexane liquid crystal. .

  As a compound that is preferably contained in a liquid crystal composition having negative dielectric anisotropy, a compound represented by the following general formula (II) can be exemplified.

<Compound represented by formula (II)>
The liquid crystal composition according to the present invention may contain at least one compound selected from compounds represented by the following general formula (II). The compound represented by the general formula (II) may contain only one type, but preferably contains two or more types.

In general formula (II), R ²¹ and R ²² are independently of each other an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or a carbon atom. The alkenyloxy group of number 2-8 is represented. R ²¹ and R ²² are independently of each other an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy having 2 to 5 carbon atoms. Group is preferable, and an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms is more preferable independently of each other. R ²¹ and R ²² may each be a branched chain group or a linear group, but are preferably a linear group.

In the general formula (II), Z ²¹ and Z ²² are each independently a single bond, —CH ₂ CH ₂ —, —CH═CH—, —CF═CF—, —CH ₂ O—, —OCH ₂ —. _{, -CF 2 O -, - OCF} 2 -, - COO- or an -OCO-. When there are a plurality of Z ²¹ and Z ²² , they may be the same or different. In the liquid crystal composition, Z ²¹ and Z ²² are independently of each other a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, preferably -COO- or -OCO- a single _{bond, -CH 2 CH 2 -, -} CH 2 O- or -OCH ₂ - is more preferable.

In the general formula (II), A ²¹ and A ²² each independently represent any group in the divalent cyclic hydrocarbon group A. When A ²¹ and A ²² are 1,4-phenylene groups, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. Further, when there are a plurality of A ²¹ and A ²² , they may be the same or different. A ²¹ and A ²² are each independently an unsubstituted 1,4-phenylene group, a 1,4-phenylene group or a 1,4-cyclohexylene group substituted with one or more fluorine atoms. An unsubstituted 1,4-phenylene group or a 1,4-cyclohexylene group is more preferable. In the liquid crystal composition of the present invention, when importance is attached to lowering the viscosity, A ²¹ and A ²² are more preferably 1,4-cyclohexylene groups in the general formula (II).

In the general formula ^{(II), a 21} and ^{a 22} represent 0 to ^3, a 21 ^{+ a 22} represents 1 to 3.

EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples.
The phase transition temperature was measured using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (DSC).
“%” In the compositions of the following examples and comparative examples means “mass%”.
T _n−i represents a transition temperature between a nematic phase and an isotropic phase.
The following abbreviations are used in compound descriptions.
THF: Tetrahydrofuran DMF: N, N-dimethylformamide DIAD: Diisopropyl azodicarboxylate TPP: Triphenylphosphine PTSA: p-toluenesulfonic acid Me: Methyl group, Pr: n-propyl group, Bu: n-butyl group

Example 1
Preparation of (4-methylphenyl)-[2,6-difluoro-4- (trans-4-propylcyclohexyl) phenyloxy] methane

(1-1) Under a nitrogen atmosphere, a solution in which 75.85 g of 3,5-difluorobromobenzene was dissolved in 150 mL of THF was added to a solution in which 10.03 g of magnesium was suspended in 50 mL of THF, and then slowly refluxed. Stir at 40 ° C. for 1 hour. After allowing to cool to room temperature, a solution prepared by dissolving 60.62 g of 4-propylcyclohexanone in 120 mL of THF was added at a rate such that the internal temperature did not exceed 35 ° C., and the mixture was stirred at room temperature for 2 hours. 10% hydrochloric acid was added until the system became acidic, and the organic layer was separated. The aqueous layer was extracted with toluene, combined with the previous organic layer, and washed with saturated brine. Sodium sulfate was added and dried, and the solvent was distilled off under reduced pressure to obtain 132 g of crude 1- (1-hydroxy-4-propylcyclohexyl) -3,5-difluorobenzene.

(1-2) 132 g of crude 1- (1-hydroxy-4-propylcyclohexyl) -3,5-difluorobenzene obtained in (1-1) and p-toluenesulfonic acid monohydrate under a nitrogen atmosphere 2.99 g was dissolved in 250 mL of toluene, and stirred for 2 hours while removing water produced under reflux. After allowing to cool to room temperature, the organic layer was washed with a saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried by adding sodium sulfate, and the solvent was distilled off under reduced pressure. Subsequently, the total amount obtained was dissolved in 280 mL of ethyl acetate, 7.1 g of 5% palladium / carbon was added, and the mixture was stirred at 5 MPa in a hydrogen atmosphere for 6 hours. After filtering off the palladium catalyst, the solvent was distilled off under reduced pressure and the residue was purified by silica gel column chromatography. Subsequently, the total amount obtained and 3.39 g of tertiary butoxy potassium were dissolved in 350 mL of DMF and stirred at room temperature for 4 hours. Water and hexane were added for liquid separation, and the organic layer was separated. The aqueous layer was extracted with hexane, and the organic layers were combined and washed with saturated brine. Sodium sulfate is added for drying, the solvent is distilled off, and distillation under reduced pressure (206 Pa, bp = 110 to 112 ° C.) is performed to give 1- (trans-4-propylcyclohexyl) -3,5-difluorobenzene. 58.05 g was obtained.

(1-3) 1- (trans-4-propylcyclohexyl) -3,5-difluorobenzene (40 g) obtained in (1-2) was dissolved in THF (200 mL) under a nitrogen atmosphere, and −40 ° C. Cooled to. Subsequently, a 1.6 mol / L butyllithium hexane solution (120 mL) was added at a rate such that the internal temperature did not become −35 ° C. or higher, and the mixture was stirred at −40 ° C. for 1 hour. Subsequently, trimethylboric acid (20.9 g) was added at a rate such that the internal temperature did not become −35 ° C. or higher, and the temperature was slowly raised to room temperature while continuing stirring. 10% Hydrochloric acid (200 mL) was added to separate the organic layer, and the aqueous layer was extracted with THF (100 mL). The organic layers were combined and washed with saturated brine (200 mL). 15% hydrogen peroxide solution (49 g) was added to the organic layer at a rate such that the internal temperature did not exceed 35 ° C., and the mixture was stirred at 35 ° C. for 16 hours. The reaction mixture was ice-cooled, 10% aqueous sodium sulfite solution (300 mL) was added at a rate such that the internal temperature did not exceed 35 ° C., and the mixture was stirred for 30 min. Toluene (150 mL) was added for liquid separation, and toluene (100 mL) was added to the aqueous layer for extraction. The organic layers were combined and washed with 10% aqueous sodium sulfite (300 mL) and saturated brine (300 mL). Sodium was added and dried. The solvent was distilled off under reduced pressure, the residue was purified by silica gel column chromatography, and further recrystallized from hexane to obtain 2,6-difluoro-4- (trans-4-propylcyclohexyl) phenol (32 g) as a white solid. .

(1-4) Under a nitrogen atmosphere, 2,6-difluoro-4- (trans-4-propylcyclohexyl) phenol (7 g), 4-methylbenzyl alcohol (3.4 g) obtained in (1-3) and Triphenylphosphine (8.3 g) was dissolved in THF (30 mL) and cooled to −10 ° C. DIAD (6.1 g) was added at a rate such that the internal temperature did not exceed 15 ° C., and the mixture was further stirred at room temperature for 2 hours. Water (1 mL) was added and stirred for 10 minutes, and the reaction mixture was concentrated under reduced pressure. Hexane (80 mL), toluene (20 mL) and 70% aqueous tertiary butyl hydroperoxide (1 g) were added, and the mixture was stirred at room temperature for 1 hour. The precipitate was removed by filtration, and the solvent was distilled off under reduced pressure. Subsequently, the residue is purified by silica gel column chromatography and recrystallized from ethanol to obtain (4-methylphenyl)-[2,6-difluoro-4- (trans-4-propylcyclohexyl) phenyloxy] methane as a white solid. As a result, 7.1 g was obtained.
MS m / z: 358 [M ⁺ ]
Phase transition temperature (° C.) Cr 43 (N 40.4) Iso
¹ HNMR (CDCl ₃ , TMS internal standard) δ (ppm) = 7.33 (2H, d, J = 8.0 Hz), 7.16 (2H, d, J = 8.0 Hz), 6.71 (2H , D, J = 9.2 Hz), 5.06 (2H, s), 2.41-2.35 (1H, m), 2.34 (3H, s), 1.87-1.83 (4H) , M), 1.39-1.17 (7H, m), 1.07-0.93 (2H, m), 0.90 (3H, t, J = 7.2 Hz)

(Example 2)
Preparation of (4-methylphenyl)-[2,6-difluoro-4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) phenyloxy] methane

(4-Methylphenyl)-[2,6-difluoro-4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) phenyloxy] methane was obtained in the same manner as in the production method described in Example 1. .
MS m / z: 440 [M ⁺ ]
Phase transition temperature (° C.): Cr 76.8 N 215.2 Iso
¹ HNMR (CDCl ₃ , TMS internal standard) δ (ppm) = 7.33 (2H, d, J = 8.0 Hz), 7.16 (2H, d, J = 8.0 Hz), 6.71 (2H , D, J = 9.2 Hz), 5.06 (2H, s), 2.41-2.35 (1H, m), 2.34 (3H, s), 1.89-1.71 (8H) , M), 1.33-1.28 (4H, m), 1.16-0.94 (9H, m), 0.89-0.83 (5H, m)

(Example 3)
Preparation of (trans-4-ethylcyclohexyl)-[2,6-difluoro-4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) phenyloxy] methane

(Trans-4-ethylcyclohexyl)-[2,6-difluoro-4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) phenyloxy] methane was prepared in the same manner as in the production method described in Example 1. Obtained.
MS m / z: 460 [M ⁺ ]
Phase transition temperature (° C.): Cr 145 SmA 148 N 226 Iso
¹ HNMR (CDCl ₃ , TMS internal standard) δ (ppm) = 6.70 (2H, d, J = 9.5 Hz), 3.87 (2H, d, J = 6.4 Hz), 2.38-2 .31 (1H, m), 1.93-1.66 (13H, m), 1.34-0.93 (19H, m), 0.90-0.81 (9H, m)

Example 4
Preparation of [4- (4-methylphenyl) phenyl]-[4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) -2,6-difluorophenyloxy] methane

(4-1) 4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] -2,6-difluorophenol (10 g), 4-bromobenzyl bromide (7) obtained as an intermediate of Example 3 0.4 g) and anhydrous potassium carbonate (8.2 g) were suspended in DMF (70 mL) and stirred at 60 ° C. for 3 hours. After allowing to cool to room temperature, water (200 mL) and toluene (200 mL) were added for liquid separation, and toluene (100 mL) was added to the aqueous layer for extraction. The organic layers were combined, washed twice with saturated brine (200 mL), dried over anhydrous sodium sulfate, and then the solvent was distilled off under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain (4-bromophenyl)-[4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) -2,6-difluorophenyloxy] methane. (14.7 g) was obtained.

(4-2) (4-Bromophenyl)-[4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) -2,6-, obtained in (4-1) under a dry nitrogen atmosphere Difluorophenyloxy] methane (14.7 g) was dissolved in THF (150 mL) and cooled to -65 ° C. A 1.6 mol / L butyl lithium / hexane solution (22 mL) was added at such a rate that the internal temperature did not become −50 ° C. or higher, and the mixture was further stirred at −65 ° C. for 1 hour. After adding trimethyl borate (3.9 g) at such a rate that the internal temperature did not become −50 ° C. or higher, the temperature was slowly raised to room temperature. The mixture was ice-cooled, 10% hydrochloric acid (100 mL) was slowly added, and toluene (150 mL) was added to separate the layers. Toluene (50 mL) was added to the aqueous layer for extraction, and the organic layers were combined and washed with water (150 mL) and saturated brine (150 mL). Anhydrous sodium sulfate is added and dried, and the solvent is distilled off under reduced pressure to give crude 4- [4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) -2,6-difluorophenyloxymethyl] phenylboric acid. (13.5 g) was obtained.

(4-3) Crude 4- [4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) -2,6-difluorophenyloxymethyl obtained in (4-2) under a dry nitrogen atmosphere Phenylboric acid (13.5 g), 4-methylbromobenzene (4.9 g), anhydrous potassium carbonate (5.9 g) and tetrakistriphenylphosphine palladium (0) (0.33 g) were dissolved in THF (150 mL). And stirred at 65 ° C. for 5 hours. After allowing to cool to room temperature, water (300 mL) and toluene (300 mL) were added to separate the layers. Toluene (150 mL) was added to the aqueous layer for extraction, and the organic layers were combined, washed with water (300 mL) and saturated brine (300 mL), and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, the residue was purified by silica gel column chromatography, and recrystallized from a mixed solvent of acetone and ethanol, whereby [4- (4-methylphenyl) phenyl]-[4- (trans-4 -(Trans-4-propylcyclohexyl) cyclohexyl) -2,6-difluorophenyloxy] methane (10.0 g) was obtained.
MS m / z: 530 [M ⁺ ]
¹ HNMR (CDCl ₃ , TMS internal standard) δ (ppm) = 7.42-7.35 (8H, m), 7.33 (2H, d, J = 8.0 Hz), 7.16 (2H, d , J = 8.0 Hz), 6.71 (2H, d, J = 9.2 Hz), 5.05 (2H, s), 2.41-2.33 (1H, m), 2.34 (3H) , S), 1.89-1.71 (8H, m), 1.33-1.28 (4H, m), 1.16-0.94 (9H, m), 0.89-0.83 (5H, m)

(Example 5)
Preparation of (4-methylphenyl)-[4- (4- (4-butenyl) phenyl) -2,6-difluorophenyloxy] methane

(5-1) Under a dry nitrogen atmosphere, 4-bromobenzyl bromide (15 g) is dissolved in THF (75 mL), and 0.8 mol / L allylmagnesium chloride / THF solution (85 mL at a rate that the internal temperature does not become 30 ° C. or higher). ) And stirred at room temperature for an additional hour. The mixture was ice-cooled, 10% hydrochloric acid (150 mL) was added, and hexane (150 mL) was added to separate the layers. Hexane (100 mL) was added to the aqueous layer for extraction, and the organic layers were combined and washed with water (150 mL) and saturated brine (150 mL). Anhydrous sodium sulfate was added for drying, the solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography to obtain 4- (4-butenyl) bromobenzene (12.3 g).

(5-2) 4- (4-butenyl) bromobenzene obtained in (5-1) with metallic magnesium (1.6 g) suspended in THF (5 mL) under a dry nitrogen atmosphere and vigorously stirred. (12.3 g) in THF (120 mL) was added at a rate such that the reaction was gently refluxed. After further stirring for 1 hour at 50 ° C., the mixture was ice-cooled, and trimethyl borate (7.2 g) was added at such a rate that the internal temperature did not become 10 ° C. or higher. After further stirring at room temperature for 1 hour, 10% hydrochloric acid (50 mL) and toluene (100 mL) were added to separate the layers. Toluene (50 mL) was added to the aqueous layer for extraction, and the organic layers were combined and washed twice with saturated brine (100 mL). Anhydrous sodium sulfate was added and dried, and the solvent was distilled off under reduced pressure to obtain crude 4- (4-butenyl) phenylboric acid (8.9 g).

(5-3) 4-Bromo-2,6-difluorophenol (10 g), 4-methylbenzyl bromide (8.8 g) and anhydrous potassium carbonate (10 g) were suspended in DMF (100 mL) at 65 ° C. Stir for 3 hours. After allowing to cool to room temperature, water (200 mL) and hexane (100 mL) were added for liquid separation, and hexane (100 mL) was added to the aqueous layer for extraction. The organic layers were combined, washed twice with saturated brine (100 mL), dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography to obtain (4-methylphenyl)-(4-bromo-2,6, -difluorophenyloxy) methane (14.4 g). .

(5-4) (4-Methylphenyl)-(4-bromo-2,6, -difluorophenyloxy) methane (14.4 g) obtained in (5-4) under a dry nitrogen atmosphere (5) -2) crude 4- (4-butenyl) phenylboric acid (8.9 g), anhydrous potassium carbonate (12.7 g) and tetrakistriphenylphosphine palladium (0) (0.53 g) were added to THF (150 mL). And stirred at 60 ° C. for 5 hours. After allowing to cool to room temperature, hexane (150 mL) and water (300 mL) were added for liquid separation, and hexane (75 mL) was added to the aqueous layer for extraction. The organic layers were combined, washed twice with saturated brine (300 mL), dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography and recrystallized from ethanol, whereby (4-methylphenyl)-[4- (4- (4-butenyl) phenyl) -2,6 -Difluorophenyloxy] methane (8.9 g) was obtained.
MS m / z: 364 [M ⁺ ]
¹ HNMR (CDCl ₃ , TMS internal standard) δ (ppm) = 7.42-7.33 (4H, m), 7.20-7.10 (6H, m), 5.86-5.79 (1H M), 5.16 (2H, s), 5.05-5.02 (2H, m), 2.56 (2H, d, J = 6.9 Hz), 2.32-2.28 (5H). , M)

(Example 6)
Preparation of liquid crystal composition-1
Host liquid crystal composition (H) having the following composition

Was prepared. Here, the physical property values of (H) are as follows.
Nematic phase upper limit temperature (T _n−i ): 117.2 ° C.
Dielectric anisotropy (Δε): 4.38
Refractive index anisotropy (Δn): 0.0899
Viscosity (η ₂₀ ): 20.3 mPa · s
A liquid crystal comprising 80% of the base liquid crystal (H) and 20% of (4-methylphenyl)-[2,6-difluoro-4- (trans-4-propylcyclohexyl) phenyloxy] methane obtained in Example 1 A composition (MA) was prepared. The physical properties of this composition are as follows.
T _n−i : 103.6 ° C.
Δε: 3.57
Δn: 0.0953
η ₂₀ : 18.3 mPa · s

The prepared liquid crystal composition (MA) maintained a uniform nematic liquid crystal state for one month or more at room temperature. As an effect of adding (4-methylphenyl)-[2,6-difluoro-4- (trans-4-propylcyclohexyl) phenyloxy] methane, the decrease in T _n-i is relatively small (extrapolated T _n-i = 49.2 ° C), Δε is hardly changed (extrapolation Δε = 0.34), and the viscosity is greatly reduced (extrapolation η ₂₀ = 10.1 mPa · s). It can be seen that the liquid crystal composition can be reduced in viscosity.

(Example 7)
Preparation of liquid crystal composition-2
Base liquid crystal (H) 80% and (4-methylphenyl)-[2,6-difluoro-4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) phenyloxy] methane obtained in Example 2 A liquid crystal composition (MB) comprising 20% was prepared. The physical properties of this composition are as follows.
T _n-i : 138.7 ° C
Δε: 3.68
Δn: 0.0984
η ₂₀ : 24.3 mPa · s

The prepared liquid crystal composition (MB) maintained a uniform nematic liquid crystal state for one month or more at room temperature. As an effect of (4-methylphenyl)-[2,6-difluoro-4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) phenyloxy] methane addition, T _n-i can be made extremely high. (Extrapolation T _n−i = 224.7 ° C.), Δε is hardly changed (extrapolation Δε = 0.89), and viscosity is not relatively increased (extrapolation η ₂₀ = 40.4 mPa · s). It can be seen that by adding this compound, it is possible to provide a liquid crystal composition having a relatively low viscosity while having a high T _n-i .

(Example 8)
Preparation of liquid crystal composition-3
80% of base liquid crystal (H) and (trans-4-ethylcyclohexyl)-[2,6-difluoro-4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) phenyloxy obtained in Example 3 A liquid crystal composition (M-C) composed of 20% methane was prepared. The physical properties of this composition are as follows.
T _n−i : 141.0 ° C.
Δε: 3.74
Δn: 0.0903
η ₂₀ : 26.1 mPa · s

The prepared liquid crystal composition (MC) maintained a uniform nematic liquid crystal state for one month or more at room temperature. As an effect of (trans-4-ethylcyclohexyl)-[2,6-difluoro-4- (trans-4- (trans-4-propylcyclohexyl) cyclohexyl) phenyloxy] methane addition, T _n-i is extremely increased. (Extrapolation T _n−i = 236.2 ° C.), Δε is hardly changed (extrapolation Δε = 1.19), and viscosity is not relatively increased (extrapolation η ₂₀ = 49.2 mPa · s). It can be seen that by adding this compound, it is possible to provide a liquid crystal composition having a relatively low viscosity while having a high T _n-i .

(Comparative Example 1)
Preparation of 4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] toluene

4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] toluene was obtained by a method similar to the method described in Example 1.
MS m / z: 298 [M ⁺ ]
Phase transition temperature (° C.): Cr 108 SmA 109 N 179 Iso
¹ HNMR (CDCl ₃ , TMS internal standard) δ (ppm) = 7.18-7.15 (4H, m), 2.42-2.35 (1H, m), 2.31 (3H, s), 1.89-1.71 (8H, m), 1.33-1.28 (4H, m), 1.16-0.94 (9H, m), 0.89-0.83 (5H, m )

(Comparative Example 2)
Preparation of liquid crystal composition-4
A liquid crystal composition (MD) comprising 80% of the base liquid crystal (H) and 20% of 4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] toluene obtained in Comparative Example 1 was prepared. The physical properties of this composition are as follows.
T _n-i : 126.4 ° C
Δε: 3.50
Δn: 0.0925
η ₂₀ : 22.9 mPa · s

When the prepared liquid crystal composition (MD) was stored at room temperature for 1 week, crystals were precipitated. Extrapolated values of physical properties of 4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] toluene are T _n−i = 163.2 ° C., Δε = −0.03, Δn = 0.103 And η ₂₀ = 33.3 mPa · s. Comparing the extrapolated value of (4-methylphenyl)-[2,6-difluoro-4- (trans-4-propylcyclohexyl) phenyloxy] methane, which is the present compound having a similar structure, the present compound is more It can be seen that the viscosity is low. Moreover, although the liquid crystal composition shown in Comparative Example 2 caused precipitation during storage at room temperature, all of the compounds of the present application showed a uniform nematic liquid crystal phase. From the above, it can be seen that the liquid crystal composition to which the present compound is added has a low viscosity and exhibits a uniform nematic liquid crystal phase. In addition, since it has a lower viscosity than the conventional liquid crystal composition, it is clear that the liquid crystal composition of the present invention has a faster response and a lower driving voltage than the conventional liquid crystal composition.

Claims (6)

General formula (1)

(Wherein, R ¹ represents an alkenyl group of an alkyl group or a carbon atom number of 2 to 15 15 carbon atom number 1, R ² is alkyl or 2 to 15 carbon atoms of from 1 to 15 carbon atoms an alkenyl group, ^{R 1} and ^{R 2} in present in one -CH ₂ - or nonadjacent two or more -CH ₂ - is -O -, - S -, - COO -, - OCO- Or may be replaced by —CO—, and one hydrogen atom or two or more hydrogen atoms present in R ¹ may be replaced by a fluorine atom;
m represents 0, 1, 2 or 3; n represents 1, 2 or 3;
A ¹ and A ² are each independently
(A) trans-1,4-cyclohexylene group (one —CH ₂ — present in this group or two or more non-adjacent —CH ₂ — represents —O—, —NH—, or — May be replaced by S-).
(B) a 1,4-phenylene group (one —CH═ present in the group or two or more non-adjacent —CH═ may be replaced by —N═);
(C) 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octane-1,4-diyl group, naphthalene-2,6-diyl group, 1,2,3,4- Represents a group selected from the group consisting of a tetrahydronaphthalene-2,6-diyl group and a decahydronaphthalene-2,6-diyl group;
The hydrogen atoms contained in the group (a), group (b) or group (c) are each independently an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a cyano group, a halogen atom. , May be substituted with a trifluoromethyl group or a trifluoromethoxy group, but when a plurality of A ¹ are present, each A ¹ may be the same or different, and when a plurality of A ² are present, Each A ² may be the same or different,
Z ¹ and Z ² are each independently —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO—, —CH ₂ CH ₂ —, —CF _{2. CF 2 -, - CH = CH} -, - CF = CF -, - C≡C- or a single bond, ^{if Z 1} there are a plurality, each ^{Z 1} may be different may be the same, Z ^{2 If} there are multiple, each Z ² may be different may be the same,
Y ¹ represents a fluorine atom. ) A compound represented by The compound according to claim 1, wherein m + n is 1 to 4 in the general formula (1). In the general formula (1), Z ¹ and Z ² each independently represent —CF ₂ O—, —OCF ₂ —, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ — or a single bond Item 3. The compound according to Item 1 or 2. In the general formula (1), A ¹ and A ² are each independently (a) 1,4-cyclohexylene group (one —CH ₂ — present in this group or two or more non-adjacent ones). —CH ₂ — may be replaced by —O—.
(B) 1,4-phenylene group (the hydrogen atom present in this group may be substituted with a methyl group, a methoxy group or a fluorine atom)
The compound according to any one of claims 1 to 3, which is a group selected from the group consisting of: A liquid crystal composition containing one or more compounds according to any one of claims 1 to 4. A liquid crystal display device using the liquid crystal composition according to claim 5.