JP6179373B2 - Liquid crystal medium, optical element, and liquid crystal compound - Google Patents

Description

  The present invention relates to a liquid crystal compound, a liquid crystal composition, an optical element using the liquid crystal composition, etc. useful as a material for an optical element, for example.

  Liquid crystal display elements using a liquid crystal composition are widely used for displays such as watches, calculators, mobile phones, personal computers, and televisions. These liquid crystal display elements utilize the refractive index anisotropy and dielectric anisotropy of liquid crystal compounds. As an operation mode in the liquid crystal display element, TN (twisted nematic), STN (super twisted nematic), BTN (Bistable twisted nematic), ECB (electrically controlled birefringence), OCB, which mainly displays using one or more polarizing plates, are used. (Optically compensated bend), IPS (in-plane switching), VA (vertical alignment), etc. are known. Furthermore, in recent years, modes in which an electric field is applied in an optically isotropic liquid crystal phase to develop electric birefringence have been studied (Patent Documents 1 to 15 and Non-Patent Documents 1 to 3).

Furthermore, wavelength tunable filters, wavefront control elements, liquid crystal lenses, aberration correction elements, aperture control elements, optical head devices, etc. using electric birefringence in the blue phase, which is one of the optically isotropic liquid crystal phases, have been proposed. (Patent Documents 10 to 12).
The classification based on the element driving method is PM (passive matrix) and AM (active matrix). PM (passive matrix) is classified into static and multiplex, and AM is classified into TFT (thin film transistor), MIM (metal insulator metal), etc., depending on the type of switching element.
A composition having chlorobenzene and an ester group is disclosed in Patent Document 15. However, the compound disclosed in Patent Document 15 has a small driving voltage reduction effect, and the driving voltage of a composition containing them is high.

JP 2003-327966 A International Publication No. 2005/90520 JP 2005-336477 A JP 2006-89622 A JP 2006-299084 A JP 2006-506477 A JP 2006-506515 A International Publication No. 2006/063662 JP 2006-225655 A JP-A-2005-157109 International Publication No. 2005/80529 JP 2006-127707 A International Publication No. 1998/023561 International Publication No. 2010/058861 JP 2009-144135 A

Nature Materials, 1, 64, (2002) Adv. Mater., 17, 96, (2005) Journal of the SID, 14, 551, (2006)

  Under the above circumstances, there is a demand for a liquid crystal medium that exhibits stability against heat, light, etc., a wide liquid crystal phase temperature range, extremely large dielectric anisotropy, and exhibits an optically isotropic liquid crystal phase. Also, various optical elements that can be used in a wide temperature range, have a short response time, a large contrast ratio, and a low driving voltage are required.

  The present invention includes, for example, the following liquid crystal compounds, liquid crystal media (liquid crystal compositions, polymer / liquid crystal composite materials, etc.), mixtures of polymerization monomers and liquid crystal compositions, optical devices containing liquid crystal media, and liquid crystal compounds. Etc.

  The present invention provides the following compound, liquid crystal medium (liquid crystal composition or polymer / liquid crystal composite), an optical element containing the liquid crystal medium, and the like.

式（１）中、Ｒ^１は水素または炭素数１〜２０のアルキルであり、当該アルキル中の少なくとも１つの−ＣＨ_２−は、−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられてもよく、当該アルキル中および当該アルキル中の−ＣＨ_２−が−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられた基中の少なくとも１つの水素はハロゲンまたは炭素数１〜３のアルキルで置き換えられてもよく；
Ｌ^１１、Ｌ^１２、Ｌ^１３、Ｌ^１４、Ｌ^１５、Ｌ^１６およびＬ^１７はそれぞれ独立して水素またはフッ素であり；
Ｘ^１はハロゲン、−ＣＦ_３、−ＯＣＦ_３、−Ｃ≡Ｎ、または−Ｎ＝Ｃ＝Ｓであり、
ｎ１１は０または１である。 [1] A liquid crystal composition containing an achiral component T containing at least one compound 1 represented by the formula (1) and a chiral agent and exhibiting an optically isotropic liquid crystal phase.

In the formula (1), R ¹ is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is —O—, —S—, —COO—, —OCO—, —CH═CH—, —CF═CF—, or —C≡C— may be substituted, and —CH ₂ — in the alkyl and the alkyl may be —O—, —S—, —COO—, — At least one hydrogen in the group replaced by OCO-, -CH = CH-, -CF = CF- or -C≡C- may be replaced by halogen or alkyl having 1 to 3 carbon atoms;
L ¹¹ , L ¹² , L ¹³ , L ¹⁴ , L ¹⁵ , L ¹⁶ and L ¹⁷ are each independently hydrogen or fluorine;
X ¹ is halogen, —CF ₃ , —OCF ₃ , —C≡N, or —N═C═S;
n11 is 0 or 1.

[2] The liquid crystal composition according to [1], wherein in formula (1), n11 is 0.

[3] The liquid crystal composition according to [1], wherein in formula (1), L ¹¹ is hydrogen and L ¹² , L ¹³ , L ¹⁶ and L ¹⁷ are fluorine.

上記式中、Ｒ^１ａは炭素数１〜１０のアルキルであり、；
Ｘ^１ａはフッ素、塩素、−Ｃ≡Ｎ、−ＣＦ_３または−ＯＣＦ_３である。 [4] The liquid crystal composition according to [1], wherein the compound represented by formula (1) is a compound represented by formulas (1-1) to (1-2).

In the above formula, R ^1a is alkyl having 1 to 10 carbons;
X ^1a is fluorine, chlorine, —C≡N, —CF ₃ or —OCF ₃ .

式（３）中、Ｒ^３は水素または炭素数１〜２０のアルキルであり、当該アルキル中の少なくとも１つの−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられてもよく、当該アルキル中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられもよく、当該アルキル中の少なくとも１つの水素はフッ素または塩素で置き換えられてもよく、ただし、当該アルキルにおいて−Ｏ−と−ＣＨ＝ＣＨ−および−ＣＯ−と−ＣＨ＝ＣＨ−が隣接することはなく；
Ｚ^３１、Ｚ^３２およびＺ^３３はそれぞれ独立して、単結合または炭素数１〜４のアルキレンであり、当該アルキレン中の少なくとも１つの−ＣＨ_２−は、−Ｏ−、−ＣＯＯ−または−ＣＦ_２Ｏ−で置き換えられてもよく；
Ｌ^３１、Ｌ^３２、Ｌ^３３，Ｌ^３４およびＬ^３５はそれぞれ独立して、水素またはフッ素であり；
Ｘ^３は水素、ハロゲン、−ＳＦ_５または炭素数１〜１０のアルキルであり、X^３中の少なくとも１つの−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられてもよく、X^３中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられもよく、X^３中の少なくとも１つの水素はフッ素または塩素で置き換えられてもよく、ただし、Ｘ^３において−Ｏ−と−ＣＨ＝ＣＨ−とが隣接することはなく、−ＣＯ−と−ＣＨ＝ＣＨ−とが隣接することはない。

式（７）中、Ｒ^７は炭素数１〜２０のアルキルであり、該アルキル中の少なくとも１つの−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられてもよく、該アルキル中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられもよく、該アルキル中の少なくとも１つの水素はフッ素または塩素で置き換えられてもよく、ただし、該アルキルにおいて−Ｏ−と−ＣＨ＝ＣＨ−および−ＣＯ−と−ＣＨ＝ＣＨ−が隣接することはなく；
Ｌ^７１、Ｌ^７２、Ｌ^７３、Ｌ^７４、Ｌ^７５、Ｌ^７６、Ｌ^７７およびＬ^７８はそれぞれ独立して、水素またはフッ素であり；
Ｚ^７１、Ｚ^７２およびＺ^７３はそれぞれ独立して、単結合、−ＣＯＯ−または−ＣＦ_２Ｏ−であるが、少なくとも一つは−ＣＯＯ−または−ＣＦ_２Ｏ−であり；
ｎ７１およびｎ７２はそれぞれ独立して０または１であり、かつｎ７１≧ｎ７２であり、；
Ｘ^７は水素、ハロゲン、−ＳＦ_５または炭素数１〜１０のアルキルであり、当該アルキレン中の少なくとも１つの−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられてもよく、当該アルキレン中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられもよく、当該アルキレン中の少なくとも１つの水素はフッ素または塩素で置き換えられてもよく、ただし、当該アルキレンにおいて−Ｏ−と−ＣＨ＝ＣＨ−とが隣接することはなく、−ＣＯ−と−ＣＨ＝ＣＨ−とが隣接することはない。 [5] Any one of [1] to [4], further including at least one compound selected from the group consisting of the compound 3 represented by the following formula (3) and the compound 7 represented by the formula (7) The liquid crystal composition according to item.

In the formula (3), R ³ is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, and at least one in the alkyl Hydrogen may be replaced by fluorine or chlorine provided that -O- and -CH = CH- and -CO- and -CH = CH- are not adjacent in the alkyl;
Z ³¹ , Z ³² and Z ³³ are each independently a single bond or alkylene having 1 to 4 carbon atoms, and at least one —CH ₂ — in the alkylene is —O—, —COO— or —CF May be replaced by ₂ O-;
L ³¹ , L ³² , L ³³ , L ³⁴ and L ³⁵ are each independently hydrogen or fluorine;
X ³ is hydrogen, halogen, —SF ₅ or alkyl having 1 to 10 carbons, and at least one —CH ₂ — in X ³ is replaced with —O—, —S—, —COO— or —OCO—. is well also, at least one _-CH 2 -CH in X ³ ₂ - is -CH = CH -, - CF = CF- or -C≡C- may be replaced by at least one in X ³ Hydrogen may be replaced by fluorine or chlorine, provided that —O— and —CH═CH— are not adjacent to each other in X ³ , and —CO— and —CH═CH— are not adjacent to each other. .

In the formula (7), R ⁷ is alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, wherein at least one hydrogen in the alkyl is May be replaced by fluorine or chlorine provided that -O- and -CH = CH- and -CO- and -CH = CH- are not adjacent in the alkyl;
L ⁷¹ , L ⁷² , L ⁷³ , L ⁷⁴ , L ⁷⁵ , L ⁷⁶ , L ⁷⁷ and L ⁷⁸ are each independently hydrogen or fluorine;
Z ^71, Z ⁷² and Z ⁷³ are each independently a single bond, —COO— or —CF ₂ O—, but at least one is —COO— or —CF ₂ O—;
n71 and n72 are each independently 0 or 1, and n71 ≧ n72;
X ⁷ is hydrogen, halogen, —SF ₅ or alkyl having 1 to 10 carbons, and at least one —CH ₂ — in the alkylene is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkylene may be replaced by —CH═CH—, —CF═CF— or —C≡C—, and at least one in the alkylene. Hydrogen may be replaced by fluorine or chlorine, provided that —O— and —CH═CH— are not adjacent to each other in the alkylene, and —CO— and —CH═CH— are not adjacent to each other. .

上記式中、Ｒ^３Ａはそれぞれ独立して、炭素数１〜１２のアルキル、炭素数１〜１２のアルコキシ、炭素数２〜１２のアルケニルまたは少なくとも１つの水素がフッ素で置き換えられてもよい炭素数２〜１２のアルケニルであり；
Ｌ^３１、Ｌ^３２、Ｌ^３３，Ｌ^３４およびＬ^３５はそれぞれ独立して水素またはフッ素であり；
Ｘ^３Ａはフッ素、塩素、−ＣＦ_３または−ＯＣＦ_３である。 [6] The liquid crystal composition according to [5], wherein compound 3 is one or more selected from the group of compounds represented by formula (3-2) and formula (3-3).

In the above formula, each R ^3A independently represents an alkyl having 1 to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl having 2 to 12 carbons or at least one hydrogen in which at least one hydrogen may be replaced by fluorine. 2 to 12 alkenyl;
L ³¹ , L ³² , L ³³ , L ³⁴ and L ³⁵ are each independently hydrogen or fluorine;
X ^3A is fluorine, chlorine, —CF ₃ or —OCF ₃ .

上記式中、Ｒ^７Ａは水素、炭素数１〜１２のアルキル、炭素数１〜１１のアルコキシ、炭素数２〜１２のアルケニル、または少なくとも１つの水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
Ｌ^７２、Ｌ^７４、Ｌ^７５、Ｌ^７６、Ｌ^７７およびＬ^７８はそれぞれ独立して、水素またはフッ素であり；
式（７−１）〜（７−３）および（７−６）〜（７−８）において、Ｚ^７１およびＺ^７２はそれぞれ独立して、単結合、−ＣＯＯ−または−ＣＦ_２Ｏ−であるが、少なくとも一つは−ＣＯＯ−または−ＣＦ_２Ｏ−であり、式（７−４）および（７−５）においては、Ｚ^７１はそれぞれ独立して、−ＣＯＯ−または−ＣＦ_２Ｏ−であり、
Ｘ^７Ａは、フッ素、塩素、−ＣＦ_３または−ＯＣＦ_３である。 [7] The liquid crystal composition according to [5], wherein the compound 7 is one or more selected from the group of compounds represented by formulas (7-1) to (7-8).

In the above formula, R ^7A is hydrogen, alkyl having 1 to 12 carbons, alkoxy having 1 to 11 carbons, alkenyl having 2 to 12 carbons, or 2 to 12 carbons in which at least one hydrogen is replaced by fluorine. Is alkenyl;
L ⁷² , L ⁷⁴ , L ⁷⁵ , L ⁷⁶ , L ⁷⁷ and L ⁷⁸ are each independently hydrogen or fluorine;
In formulas (7-1) to (7-3) and (7-6) to (7-8), Z ⁷¹ and Z ⁷² are each independently a single bond, —COO— or —CF ₂ O—. And at least one is —COO— or —CF ₂ O—, and in formulas (7-4) and (7-5), Z ⁷¹ independently represents —COO— or —CF ₂ O. −
X ^7A is fluorine, chlorine, —CF ₃ or —OCF ₃ .

（上記式中、Ｒ^７Ａは、炭素数１〜１２のアルキル、炭素数１〜１１のアルコキシ、炭素数２〜１２のアルケニル、または少なくとも１つの水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
Ｘ^７Ａは、フッ素、塩素、−ＣＦ_３または−ＯＣＦ_３である。） [8] Compound 7 is represented by formulas (7-2-2-E), (7-2-5-E), (7-2-2F), (7-2-5-F) and (7 The liquid crystal composition according to [7], which is one or more selected from the group of compounds represented by -2-6-F).

(In the above formula, R ^7A is an alkyl having 1 to 12 carbons, an alkoxy having 1 to 11 carbons, an alkenyl having 2 to 12 carbons, or a carbon having 2 to 12 carbons in which at least one hydrogen is replaced with fluorine. Is alkenyl;
X ^7A is fluorine, chlorine, —CF ₃ or —OCF ₃ . )

[9] The total weight of the achiral component T is 3 to 20% by weight of Compound 1, the total of Compound 3 is 20 to 67% by weight, and the total of Compound 7 is 30% by weight. The liquid crystal composition according to [5], which is contained by 77% by weight.

式（４）中、Ｒ^４は、炭素数１〜１２のアルキル、炭素数１〜１２のアルコキシ、炭素数２〜１２のアルケニル、または少なくとも１つの水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
環Ｂはそれぞれ独立して、１，４−シクロへキシレン、１，４−フェニレン、２−フルオロ−１，４−フェニレン、３−フルオロ−１，４−フェニレン、３，５−ジフルオロ−１，４−フェニレン、３，５−ジクロロ−１，４−フェニレンまたはピリミジン−２，５−ジイルであり；
Ｚ^４１はそれぞれ独立して、単結合、エチレン、−ＣＯＯ−、−ＯＣＯ−、−ＣＦ_２Ｏ−または−ＯＣＦ_２−であり；
Ｌ^４８およびＬ^４９はそれぞれ独立して、水素またはフッ素であり；
Ｘ^４はフッ素、塩素、−ＣＦ_３または−ＯＣＦ_３であり；
ｎ４１は、１、２、３または４であり、ただしｎ４１が３または４である場合、少なくとも１つのＺ^４１は−ＣＦ_２Ｏ−または−ＯＣＦ_２−であり、ｎ４１が３の場合は、環Ｂのすべてがフッ素で置換された１，４−フェニレンであることはない。

式（２）中、Ｒ^２は水素または炭素数１〜２０のアルキルであり、当該アルキル中の少なくとも１つの−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられてもよく、当該アルキル中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられもよく、当該アルキル中、アルキル中の少なくとも１つの−ＣＨ_２−が−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられた基中、またはアルキル中の少なくとも１つの−ＣＨ_２−が−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられた基中の少なくとも１つの−ＣＨ_２−ＣＨ_２−が−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−で置き換えられた基中の少なくとも１つの水素はフッ素または塩素で置き換えられてもよく、ただし、Ｒ^２において−Ｏ−と−ＣＨ＝ＣＨ−および−ＣＯ−と−ＣＨ＝ＣＨ−が隣接することはなく；
環Ａ^２１、環Ａ^２２、環Ａ^２３、環Ａ^２４および環Ａ^２５はそれぞれ独立して、１，４−シクロへキシレン、１，３−ジオキサン−２，５−ジイル、１，４−フェニレン、１つまたは２つの水素がフッ素で置き換えられた１，４−フェニレン、２つの水素がそれぞれフッ素と塩素で置き換えられた１，４−フェニレン、ピリジン−２，５−ジイル、ピリミジン−２，５−ジイルであり；
Ｚ^２１、Ｚ^２２、Ｚ^２３、Ｚ^２４、Ｚ^２５およびＺ^２６はそれぞれ独立して、単結合または炭素数１〜４のアルキレンであり、当該アルキレン中の少なくとも１つの−ＣＨ_２−は、−Ｏ−、−ＣＯＯ−または−ＣＦ_２Ｏ−で置き換えられてもよく；
Ｌ^２１、Ｌ^２２およびＬ^２３はそれぞれ独立して、水素またはフッ素であり；
Ｘ^２はフッ素、塩素、−ＣＦ_３、−ＣＨＦ_２、−ＣＨ_２Ｆ、、−ＯＣＦ_３、−ＯＣＨＦ_２、−ＯＣＨ_２Ｆ、−ＯＣＦ_２ＣＦＨＣＦ_３または−ＣＨ＝ＣＨＣＦ_３であり；
ｎ２１、ｎ２２、ｎ２３、ｎ２４およびｎ２５はそれぞれ独立して、０または１であり、２≦ｎ２１＋ｎ２２＋ｎ２３＋ｎ２４＋ｎ２５≦３である。 [10] The [1] to [9], wherein the achiral component T further includes at least one compound selected from the group of the compound 4 represented by the formula (4) and the compound 2 represented by (2). ] The liquid crystal composition as described in any one of.

In the formula (4), R ⁴ is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or 2 to 12 carbons in which at least one hydrogen is replaced with fluorine. Alkenyl of
Each ring B is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 3,5-difluoro-1, 4-phenylene, 3,5-dichloro-1,4-phenylene or pyrimidine-2,5-diyl;
Each Z ⁴¹ is independently a single bond, ethylene, —COO—, —OCO—, —CF ₂ O— or —OCF ₂ —;
L ⁴⁸ and L ⁴⁹ are each independently hydrogen or fluorine;
X ⁴ is fluorine, chlorine, —CF ₃ or —OCF ₃ ;
n41 is 1, 2, 3 or 4, provided that when n41 is 3 or 4, at least one Z ⁴¹ is —CF ₂ O— or —OCF ₂ —, and when n41 is 3, Not all of B is 1,4-phenylene substituted with fluorine.

In the formula (2), R ² is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, In a group in which at least one —CH ₂ — is replaced by —O—, —S—, —COO— or —OCO—, or at least one —CH ₂ — in alkyl is —O—, —S—, At least one hydrogen in the group in which at least one —CH ₂ —CH ₂ — in the group replaced with —COO— or —OCO— is replaced with —CH═CH— or —C≡C— is fluorine or Replace with chlorine May be, however, -O- and -CH = CH- and -CO- and -CH = CH- not be adjacent in ^{R 2;}
Ring A ²¹ , Ring A ²² , Ring A ²³ , Ring A ²⁴ and Ring A ²⁵ are each independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene. 1,4-phenylene in which one or two hydrogens are replaced with fluorine, 1,4-phenylene in which two hydrogens are replaced with fluorine and chlorine, respectively, pyridine-2,5-diyl, pyrimidine-2,5 -Diyl;
Z ²¹ , Z ²² , Z ²³ , Z ²⁴ , Z ²⁵ and Z ²⁶ are each independently a single bond or alkylene having 1 to 4 carbon atoms, and at least one —CH ₂ — in the alkylene is — O -, - COO- or may be replaced by _-CF 2 O-;
L ²¹ , L ²² and L ²³ are each independently hydrogen or fluorine;
X ² is fluorine, chlorine, —CF ₃ , —CHF ₂ , —CH ₂ F, —OCF ₃ , —OCHF ₂ , —OCH ₂ F, —OCF ₂ CFHCF ₃ or —CH═CHCF ₃ ;
n21, n22, n23, n24 and n25 are each independently 0 or 1, and 2 ≦ n21 + n22 + n23 + n24 + n25 ≦ 3.

（上記式中、Ｒ^４Ａはそれぞれ独立して、炭素数１〜１２のアルキル、炭素数１〜１２のアルコキシ、炭素数２〜１２のアルケニルまたは少なくとも１つの水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
Ｘ^４Ａはフッ素、塩素、−ＣＦ_３または−ＯＣＦ_３であり；
Ｌ^４０〜Ｌ^４９はそれぞれ独立して水素またはフッ素である。

上記式中、Ｒ^２Ａは炭素数１〜１２のアルキル、炭素数１〜１２のアルコキシ、炭素数２〜１２のアルケニル、または、少なくとも１つの水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
（Ｆ）はそれぞれ独立して、水素またはフッ素であり；
Ｘ^２Ａは、フッ素、塩素、−ＣＦ_３または−ＯＣＦ_３である。 [11] Compound 4 is one or more selected from the group of compounds represented by formulas (4-1) to (4-9), and compound 2 is represented by formula (2-1-1-2), (2-1-2-1), (2-1-3-1), (2-1-3-2), (2-1-4-2) and (2-1-4-3) The liquid crystal composition according to [10], which is one or more selected from the group of compounds represented.

(In the above formula, each R ^4A independently represents an alkyl having 1 to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl having 2 to 12 carbons or at least one hydrogen in which at least one hydrogen is replaced by fluorine. -12 alkenyl;
X ^4A is fluorine, chlorine, —CF ₃ or —OCF ₃ ;
L ^{40 to} L ⁴⁹ are each independently hydrogen or fluorine.

In the above formula, R ^2A is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12 carbons in which at least one hydrogen is replaced by fluorine. Is;
(F) is each independently hydrogen or fluorine;
X ^2A is fluorine, chlorine, —CF ₃ or —OCF ₃ .

（上記式中、Ｒ^Ｋはそれぞれ独立して、水素、ハロゲン、−Ｃ≡Ｎ、−Ｎ＝Ｃ＝Ｏ、−Ｎ＝Ｃ＝Ｓまたは炭素数１〜２０のアルキルであり、当該アルキル中の少なくとも１つの−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられてもよく、当該アルキル中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられもよく、当該アルキル中の少なくとも１つの水素はフッ素または塩素で置き換えられてもよく；
Ａはそれぞれ独立して、芳香族性の６〜８員環、非芳香族性の３〜８員環、または、炭素数９以上の縮合環であり、これらの環の少なくとも１つの水素はハロゲン、炭素数１〜３のアルキルまたはハロアルキルで置き換えられてもよく、環の−ＣＨ_２−は−Ｏ−、−Ｓ−または−ＮＨ−で置き換えられてもよく、−ＣＨ＝は−Ｎ＝で置き換えられてもよく；
Ｂはそれぞれ独立して、水素、ハロゲン、炭素数１〜３のアルキル、炭素数１〜３のハロアルキル、芳香族性の６〜８員環、非芳香族性の３〜８員環、または、炭素数９以上の縮合環であり、これらの環の少なくとも１つの水素がハロゲン、炭素数１〜３のアルキルまたはハロアルキルで置き換えられてもよく、当該アルキル中の−ＣＨ_２−は−Ｏ−、−Ｓ−または−ＮＨ−で置き換えられてもよく、−ＣＨ＝は−Ｎ＝で置き換えられてもよく；
Ｚはそれぞれ独立して、単結合、炭素数１〜８のアルキレンであり、当該アルキレン中の少なくとも１つの−ＣＨ_２−は、−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＳＯ−、−ＯＣＳ−、−Ｎ＝Ｎ−、−ＣＨ＝Ｎ−または−Ｎ＝ＣＨ−で置き換えられてもよく、当該アルキレン中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられてもよく、当該アルキレン中の少なくとも１つの水素はハロゲンで置き換えられてもよく；
Ｘはそれぞれ独立して、単結合、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、または−ＣＨ_２ＣＨ_２−であり；
ｍＫはそれぞれ独立して、１〜４の整数である。） [12] The liquid crystal composition according to any one of [1] to [11], wherein the chiral agent is at least one compound selected from the group of compounds represented by formulas (K1) to (K6). object.

(In the formula, ^{R K} is independently hydrogen, halogen, -C≡N, alkyl of -N = C = O, -N = C = S or a C 1-20, in the alkyl At least one —CH ₂ — may be replaced by —O—, —S—, —COO— or —OCO—, and at least one —CH ₂ —CH ₂ — in the alkyl is —CH═CH—. , -CF = CF- or -C≡C-, and at least one hydrogen in the alkyl may be replaced by fluorine or chlorine;
Each A is independently an aromatic 6-8 membered ring, a non-aromatic 3-8 membered ring, or a condensed ring having 9 or more carbon atoms, and at least one hydrogen of these rings is a halogen atom , C 1 -C 3 alkyl or haloalkyl may be substituted, ring —CH ₂ — may be substituted with —O—, —S— or —NH—, and —CH═ is —N═. May be replaced;
Each B is independently hydrogen, halogen, alkyl having 1 to 3 carbon atoms, haloalkyl having 1 to 3 carbon atoms, aromatic 6 to 8 membered ring, non-aromatic 3 to 8 membered ring, or A condensed ring having 9 or more carbon atoms, and at least one hydrogen of these rings may be replaced by halogen, alkyl having 1 to 3 carbon atoms or haloalkyl, and —CH ₂ — in the alkyl is —O—, -S- or -NH- may be substituted and -CH = may be replaced by -N =;
Z is each independently a single bond or alkylene having 1 to 8 carbon atoms, and at least one —CH ₂ — in the alkylene is —O—, —S—, —COO—, —OCO—, — CSO—, —OCS—, —N═N—, —CH═N— or —N═CH— may be substituted, and at least one —CH ₂ —CH ₂ — in the alkylene is —CH═CH. -, -CF = CF- or -C≡C- may be substituted, and at least one hydrogen in the alkylene may be replaced by halogen;
Each X is independently a single bond, —COO—, —OCO—, —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, or —CH ₂ CH ₂ —;
mK is each independently an integer of 1 to 4. )

[13] In any one of [1] to [12], a chiral nematic phase is exhibited at any temperature of −20 ° C. to 70 ° C., and the helical pitch is 700 nm or less in at least a part of this temperature range. The liquid crystal composition described.

[14] A mixture comprising the liquid crystal composition according to any one of [1] to [13] and a polymerizable monomer.

[15] A polymer / liquid crystal composite material obtained by polymerizing the mixture according to [14] and used for an element driven in an optically isotropic liquid crystal phase.

[16] An optical element comprising an electrode disposed on one or both substrates, a liquid crystal medium disposed between the substrates, and an electric field applying means for applying an electric field to the liquid crystal medium via the electrodes, , [1] to [13] The liquid crystal composition according to any one of [1] to [13], or the polymer / liquid crystal composite material according to [15].

[17] Use of the liquid crystal composition according to any one of [1] to [13] or the polymer / liquid crystal composite material according to [15] for an optical element.

上記式中、Ｒ^１ａは炭素数１〜１０のアルキルであり、；
Ｘ^１ａはフッ素、塩素、−Ｃ≡Ｎ、−ＣＦ_３または−ＯＣＦ_３である。 [18] Compounds represented by formula (1-1) and formula (1-2).

In the above formula, R ^1a is alkyl having 1 to 10 carbons;
X ^1a is fluorine, chlorine, —C≡N, —CF ₃ or —OCF ₃ .

In this specification, the “liquid crystal compound” represents a compound having a mesogen, and is not limited to a compound that exhibits a liquid crystal phase. Specifically, it is a generic term for a compound that exhibits a liquid crystal phase such as a nematic phase or a smectic phase, and a compound that does not have a liquid crystal phase but is useful as a component of a liquid crystal composition.
“Liquid crystal medium” is a general term for a liquid crystal composition and a polymer / liquid crystal composite.
An “achiral component” is an achiral mesogenic compound that does not include an optically active compound and a compound having a polymerizable functional group. Accordingly, the “achiral component” does not include a chiral agent, a monomer, a polymerization initiator, an antioxidant, an ultraviolet absorber, a curing agent, a stabilizer, and the like.
The “chiral agent” is an optically active compound and is a component used to be added to give a desired twisted molecular arrangement to the liquid crystal composition.
“Liquid crystal display element” is a general term for liquid crystal display panels and liquid crystal display modules.
“Optical element” refers to various elements that perform functions such as light modulation and optical switching by utilizing the electro-optic effect. For example, display elements (liquid crystal display elements), optical communication systems, optical information processing, and the like. And light modulation elements used in various sensor systems. The Kerr effect is known for light modulation using a change in refractive index caused by voltage application to an optically isotropic liquid crystal medium. The Kerr effect is a phenomenon in which the electric birefringence value Δn (E) is proportional to the square of the electric field E, and Δn (E) = KλE ² holds for a material exhibiting the Kerr effect (K: Kerr coefficient (Kerr constant), λ: wavelength)). Here, the electric birefringence value is a refractive index anisotropy value induced when an electric field is applied to the isotropic medium.

“Liquid crystal compound”, “liquid crystal composition”, and “liquid crystal display element” may be abbreviated as “compound”, “composition”, and “element”, respectively.
For example, the upper limit temperature of the liquid crystal phase is a phase transition temperature of the liquid crystal phase-isotropic phase, and may simply be abbreviated as the clearing point or the upper limit temperature. The lower limit temperature of the liquid crystal phase may be simply abbreviated as the lower limit temperature. The compound represented by Formula (1) may be abbreviated as Compound 1. This abbreviation may also apply to compounds represented by formula (2) and the like. In formulas (2) to (5), symbols such as A ¹ , B, and C surrounded by hexagons correspond to ring A ¹ , ring B, and ring C, respectively. The amount of the compound expressed as a percentage is a weight percentage (% by weight) based on the total weight of the composition. A plurality of the same symbols such as rings A ¹ , Y ¹ , and B are described in the same formula or different formulas, but these may be the same or different.

In the present specification, specific examples of “alkyl” include —CH ₃ , —C ₂ H ₅ , —C ₃ H ₇ , —C ₄ H ₉ , —C ₅ H ₁₁ , —C ₆ H ₁₃ , —C _{7. H 15, -C 8 H 17,} -C 9 H 19, -C 10 H 21, -C 11 H 23, -C 12 H 25, -C 13 H 27, -C 14 H 29, and _{-C 15} H ₃₁ .

In the present specification, specific examples of “alkoxy” include —OCH ₃ , —OC ₂ H ₅ , —OC ₃ H ₇ , —OC ₄ H ₉ , —OC ₅ H ₁₁ , —OC ₆ H ₁₃ and —OC _{7. H 15, -OC 8 H 17,} -OC 9 H 19, -OC 10 H 21, -OC 11 H 23, -OC 12 H 25, -OC 13 H 27, and include _-OC 14 _{H 29.}

In the present specification, specific examples of “alkoxyalkyl” include —CH ₂ OCH ₃ , —CH ₂ OC ₂ H ₅ , —CH ₂ OC ₃ H ₇ , — (CH ₂ ) ₂ —OCH ₃ , — (CH _2). ) ₂ -OC ₂ H ₅ ,-(CH ₂ ) ₂ -OC ₃ H ₇ ,-(CH ₂ ) ₃ -OCH ₃ ,-(CH ₂ ) ₄ -OCH ₃ , and-(CH ₂ ) ₅ -OCH ₃ Is mentioned.

In the present specification, specific examples of “alkenyl” include —CH═CH ₂ , —CH═CHCH ₃ , —CH ₂ CH═CH ₂ , —CH═CHC ₂ H ₅ , —CH ₂ CH═CHCH ₃ , — _{(CH 2) 2 -CH = CH} 2, -CH = CHC 3 H 7, -CH 2 CH = CHC 2 H 5, - (CH 2) 2 -CH = CHCH 3, and _{- (CH} 2) 3 -CH = CH _2.

In the present specification, specific examples of “alkenyloxy” include —OCH ₂ CH═CH ₂ , —OCH ₂ CH═CHCH ₃ , and —OCH ₂ CH═CHC ₂ H ₅ .

In the present specification, specific examples of “alkynyl” include —C≡CH, —C≡CCH ₃ , —CH ₂ C≡CH, —C≡CC ₂ H ₅ , —CH ₂ C≡CCH ₃ , — (CH ₂ ) ₂ —C≡CH, —C≡CC ₃ H ₇ , —CH ₂ C≡CC ₂ H ₅ , — (CH ₂ ) ₂ —C≡CCH ₃ , and —C≡C (CH ₂ ) ₅ It is done.

  In the present specification, specific examples of “halogen” include fluorine, chlorine, bromine, and iodine.

Preferred compounds of the present invention exhibit liquid crystallinity, have a relatively high clearing point, a wide nematic phase temperature range, and a large dielectric anisotropy.
Preferred liquid crystal compositions and polymer / liquid crystal composite materials of the present invention exhibit stability against heat, light, etc., high maximum temperature and low minimum temperature of optically isotropic liquid crystal phase, and large dielectric anisotropy Have sex. In addition, the polymer / liquid crystal composite material according to a preferred embodiment of the present invention has a high upper limit temperature and a lower lower limit temperature of an optically isotropic liquid crystal phase, and is driven by an optically isotropic liquid crystal phase. Has a low driving voltage.
In addition, the optical element driven by the optically isotropic liquid crystal phase according to the preferred embodiment of the present invention can be used in a wide temperature range, can be driven at a low voltage, and can achieve a high-speed electro-optical response. And has a large contrast ratio.

The comb-shaped electrode substrate used in the Example is shown. The optical system used in the Example is shown.

  The liquid crystal composition having an optically isotropic liquid crystal phase of the present invention contains an achiral component T and a chiral agent, and the achiral component T contains the compound represented by the formula (1) as a first component. . The first aspect of the liquid crystal composition of the present invention is a composition containing a first component and other components not particularly indicated in the present specification. First, the compound represented by Formula (1) is demonstrated. In addition to the above components, the liquid crystal composition of the present invention may further contain a solvent, a monomer, a polymerization initiator, a curing agent, a stabilizer (an antioxidant, an ultraviolet absorber, etc.) and the like.

1-1 Compound 1
In the formula (1), R ¹ is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is —O—, —S—, —COO—, —OCO—, —CH═CH—, —CF═CF—, or —C≡C— may be substituted, and —CH ₂ — in the alkyl and the alkyl may be —O—, —S—, —COO—, — At least one hydrogen in the group replaced by OCO-, -CH = CH-, -CF = CF- or -C≡C- may be replaced by halogen or alkyl having 1 to 3 carbon atoms.
For example, as an example of a group in which at least one —CH ₂ — in CH ₃ (CH ₂ ) ₃ — is replaced by —O—, —S— or —CH═CH—, CH ₃ (CH ₂ ) ₂ O—, _{CH 3 -O- (CH 2) 2} -, CH 3 -O-CH 2 -O-, CH 3 (CH 2) 2 S-, CH 3 -S- (CH 2) 2 -, CH 3 -S- _{CH 2 -S-, CH 2 = CH-} (CH 2) 3 -, CH 3 -CH = CH- (CH 2) 2 -, CH 3 -CH = CH-CH 2 O-, CH 3 CH 2 C≡ C- etc. are mentioned. For example, in a group in which at least one —CH ₂ — in CH ₃ (CH ₂ ) ₃ — or CH ₃ (CH ₂ ) ₃ — is replaced by —O—, —C≡C— or —CH═CH—. Examples of groups in which at least one hydrogen has been replaced by halogen include ClCH ₂ (CH ₂ ) ₃ —, CF ₂ ═CH— (CH ₂ ) ₃ —, CH ₂ F (CH ₂ ) ₂ O—, CH ₂ FCH. ₂ C≡C— and the like.

The preferred configuration of —CH═CH— in R ¹ depends on the position of the double bond. _{-CH = CHCH 3, -CH = CHC} 2 H 5, -CH = CHC 3 H 7, -CH = CHC 4 H 9, -C 2 H 4 CH = CHCH 3, and _{-C 2 H} 4 CH = CHC 2 In alkenyl having a double bond at odd positions such as H ₅ , the trans configuration is preferable. -CH ₂ CH ₌ CHCH _3, cis configuration in the alkenyl having an even position to the double bond, such as _{-CH 2 CH = CHC 2 H 5} , and _-CH 2 CH = _CHC 3 _{H 7} are preferred. An alkenyl compound having a preferred configuration has a high maximum temperature or a wide temperature range of the liquid crystal phase. Mol. Cryst. Liq. Cryst., 1985, 131, 109 and Mol. Cryst. Liq. Cryst., 1985, 131, 327 have detailed descriptions. The position of the alkenyl group is preferably a position that does not form a conjugate with the benzene ring.

The alkyl in R ¹ may be linear or branched, and specific examples of alkyl are —CH ₃ , —C ₂ H ₅ , —C ₃ H ₇ , —C ₄ H ₉ , —C ₅ H _{11. , -C 6 H 13, -C 7} H 15, -C 8 H 17, -C 9 H 19, -C 10 H 21, -C 11 H 23, -C 12 H 25, -C 13 H 27, - C ₁₄ H _29, and _-C are 15 _{H 31.}

The alkoxy in R ¹ may be linear or branched, and specific examples of alkoxy include —OCH ₃ , —OC ₂ H ₅ , —OC ₃ H ₇ , —OC ₄ H ₉ , —OC ₅ H _11. , _-OC 6 _{H 13} and _{-OC 7 H 15, -OC 8 H} 17, -OC 9 H 19, -OC 10 H 21, -OC 11 H 23, -OC 12 H 25, -OC 13 H 27, and it is -OC ₁₄ H _29.

The alkoxyalkyl in R ¹ may be linear or branched, and specific examples of alkoxyalkyl include —CH ₂ OCH ₃ , —CH ₂ OC ₂ H ₅ , —CH ₂ OC ₃ H ₇ , — (CH _{2) 2 -OCH 3, - (} CH 2) 2 -OC 2 H 5, - (CH 2) 2 -OC 3 H 7, - (CH 2) 3 -OCH 3, - (CH 2) 4 -OCH 3 , and _- a _(CH 2) 5 -OCH _3.

The alkenyl in R ¹ may be linear or branched, and specific examples of alkenyl include —CH ₂ CH═CH ₂ , —CH ₂ CH═CHCH ₃ , — (CH ₂ ) ₂ —CH═CH _{2. , -CH 2 CH = CHC 2 H} 5, - (CH 2) 2 -CH = CHCH 3, and _- a _{(CH 2) 3 -CH = CH} 2.

The alkenyloxy in R ¹ may be linear or branched, and specific examples of alkenyloxy include —OCH ₂ CH═CH ₂ , —OCH ₂ CH═CHCH ₃ , and —OCH ₂ CH═CHC ₂ H. ₅ .

The alkynyl in R ¹ may be linear or branched, and specific examples of alkynyl include —C≡CH, —C≡CCH ₃ , —CH ₂ C≡CH, —C≡CC ₂ H ₅ , —CH. ₂ C≡CCH ₃ , — (CH ₂ ) ₂ —C≡CH, —C≡CC ₃ H ₇ , —CH ₂ C≡CC ₂ H ₅ , — (CH ₂ ) ₂ —C≡CCH ₃ , and —C ≡C (CH ₂ ) ₅

（上記式中、Ｒ^１ａは水素または炭素数１〜２０のアルキルである。） R ¹ is preferably a structure represented by the formulas (CHN-1) to (CHN-6). More preferred is (CHN-1) or (CHN-2).

(In the above formula, R ^1a is hydrogen or alkyl having 1 to 20 carbon atoms.)

In the formula (1), L ¹¹ , L ¹² , L ¹³ , L ¹⁴ , L ¹⁵ , L ¹⁶ and L ¹⁷ are each independently hydrogen or fluorine, but the compound in which L ¹¹ is hydrogen is a phase at low temperature. Those having good solubility and having L ¹¹ of fluorine have a large dielectric anisotropy. Preferred L ¹¹ is hydrogen. A compound in which all of L ^{12 to} L ¹⁶ are hydrogen has a high clearing point and good compatibility at low temperatures. A compound in which only one of L ^{12 to} L ¹⁶ is fluorine has a large dielectric anisotropy. L ¹² , L ¹³ , if present, L ¹⁴ , L ¹⁶ and L ¹⁷ are fluorine, and L ¹¹ and, if present, a compound wherein L ¹⁵ is hydrogen, have a good balance between the dielectric constant and compatibility. is there.

In formula (1), X ¹ is halogen, —CF ₃ , —OCF ₃ , —C≡N, or —N═C═S.

Preferred examples of X ¹ are fluorine, —C≡N, —CF ₃ .
More preferred examples of X ¹ are fluorine and —CF ₃ .

（上記式中、Ｒ^１ａは炭素数１〜１０のアルキルであり、；
Ｘ^１ａはフッ素、塩素、−Ｃ≡Ｎ、−ＣＦ_３または−ＯＣＦ_３である。） The compound 1 is preferably a compound represented by the formulas (1-1) to (1-2).

(Wherein R ^1a is alkyl having 1 to 10 carbons;
X ^1a is fluorine, chlorine, —C≡N, —CF ₃ or —OCF ₃ . )

1-2 Properties of Compound 1 Compound 1 is physically and chemically extremely stable under conditions in which the device is normally used. A compound having n11 = 1 has a relatively large dielectric anisotropy and a large refractive index. It has anisotropy, high clearing point, and relatively good compatibility with other compounds. A composition containing this compound is stable under conditions in which the device is normally used. Therefore, when the compound 1 with n11 = 1 is used in the liquid crystal composition, the temperature range of the liquid crystal phase can be widened, and can be used as a display element in a wide temperature range.
Since the compound 1 having n11 = 0 has a large dielectric anisotropy and a relatively large refractive index anisotropy, the compound 1 is a liquid crystal composition driven by an optically isotropic liquid crystal phase. It is useful as a component for lowering the drive voltage.
Compound 1 has an excellent feature that the clearing point can be increased only by using a small amount, or the driving voltage is lowered, and the temperature range on the low temperature side is widened.

1-3 Synthesis of Compound 1 Compound 1 can be synthesized by appropriately combining methods in known organic synthetic chemistry. There are a plurality of methods for synthesizing Compound 1, which can be appropriately synthesized from commercially available reagents.
In addition, when synthesizing Compound 1, the methods for introducing the desired terminal group, ring and linking group into the starting material are as follows: Organic Syntheses, John Wiley & Sons, Inc., Organic Reactions, John Wiley & Sons, Inc), Comprehensive Organic Synthesis (Pergamon Press), New Experimental Chemistry Course (Maruzen).

  An example of a scheme for synthesizing compound 1 is shown below, but the synthesis of compound 1 is not limited to this scheme.

1-3-1. Synthesis of Compound (102) Halogen compounds (101) and (102) are commercially available or can be prepared by general organic chemical synthesis methods. The compound (103) can be derived by preparing a Grignard reagent by allowing a metal such as magnesium to act on the halogen compound (102) and further performing a cross-coupling reaction with the halogen compound (101) under a palladium catalyst.
1-3-2 Synthesis of Compound (104) After using Compound (103) as a lithium reagent using butyllithium or the like, iodine is allowed to act to obtain an iodine compound. Next, the obtained iodine compound is subjected to a Suzuki coupling reaction with 3-fluoro-5-chloro-phenylboronic acid in the presence of a base such as potassium carbonate and a palladium catalyst, whereby the compound (104) can be obtained.

1-3-3 Synthesis of Compound (106) After using Compound (104) as a lithium reagent using butyllithium or the like, iodine is allowed to act to obtain an iodine compound. Next, the resulting iodine compound is subjected to a Suzuki coupling reaction with the corresponding phenylboronic acid (105) in the presence of a base such as potassium carbonate and a palladium catalyst, whereby the compound (106) can be obtained.

1-3-4 Synthesis of Compound (1) After using Compound (106) as a lithium reagent using butyllithium or the like, carbon dioxide gas is allowed to act to obtain carboxylic acid derivative (107). The resulting carboxylic acid derivative (107) is subjected to an esterification reaction using dicyclohexylcarbodiimide (DCC) and dimethylaminopyridine (DMAP) to obtain compound (1).

2-1 Liquid Crystal Composition The liquid crystal composition of the present invention is a composition containing the compound 1 represented by the formula (1) and expressing an optically isotropic liquid crystal phase. Further, the optically isotropic liquid crystal composition contains a chiral agent in addition to the achiral component T containing the compound 1, and may further contain an antioxidant, an ultraviolet absorber, a stabilizer and the like.

The achiral component T includes a case where the compound 1 is composed of one compound and a case where the compound 1 contains two or more compounds represented by the formula (1). Furthermore, the achiral component includes one or more compounds selected from the group consisting of compounds 3 to 7 as necessary. The achiral component T preferably includes compounds 2, 3, 5 and 7 in addition to compound 1, particularly preferably includes compounds 3 and 7, and further includes compounds 4 and 6 depending on the properties required. Can do. Compounds 1 and 3-7 are liquid crystal compounds.
Since Compound 1 has a relatively high clearing point, a large dielectric anisotropy, and a relatively good compatibility at low temperatures, the achiral component T using Compound 1 also has a wide liquid crystal phase temperature range or a large dielectric constant difference. Develops anisotropy. Therefore, an optically isotropic liquid crystal composition using the achiral component T is also useful as a composition used for an optical element.
The total amount of compound 1 is preferably 1-30% by weight, more preferably 3-20% by weight, even more preferably 5-15% by weight, based on the total weight of the achiral component T. It is particularly preferable to do this.
In order to develop a large dielectric anisotropy, it is preferable to further add a compound selected from the group represented by compounds 3 and 7. Since this composition exhibits a very large dielectric anisotropy, it is an extremely effective composition for lowering the voltage of an optical element.

式中、Ｒ^２は水素または炭素数１〜２０のアルキルであり、当該アルキル中の少なくとも１つの−ＣＨ_２−は、−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられてもよく、当該アルキル中および当該アルキル中の−ＣＨ_２−が−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられた基中の少なくとも１つの水素はハロゲンまたは炭素数１〜３のアルキルで置き換えられてもよく；環Ａ^２１、環Ａ^２２、環Ａ^２３、環Ａ^２４、および環Ａ^２５は独立して、１，４−シクロへキシレン、１，３−ジオキサン−２，５−ジイル、１，４−フェニレン、１つまたは２つの水素がフッ素で置き換えられた１，４−フェニレン、２つの水素がそれぞれフッ素と塩素で置き換えられた１，４−フェニレン、ピリジン−２，５−ジイル、ピリミジン−２，５−ジイルであり；Ｚ^２１、Ｚ^２２、Ｚ^２３、Ｚ^２４、Ｚ^２５、およびＺ^２６は独立して、単結合または−ＣＦ_２Ｏ−であり、；Ｌ^２１、Ｌ^２２およびＬ^２３は独立して、水素またはフッ素であり；Ｘ^２はフッ素、塩素、−ＣＦ_３、または−ＯＣＦ_３であり；ｎ２１、ｎ２２、ｎ２３、ｎ２４、およびｎ２５は独立して、０または１であり、２≦ｎ２１＋ｎ２２＋ｎ２３＋ｎ２４＋ｎ２５≦３である。 2-2-1 Compound 2
In addition to compound 1, the achiral component of the present invention may further contain one or more compounds 2 represented by formula (2). That is, the present invention includes a case where the achiral component T is composed of one compound as the compound 2 and a case where the compound 2 includes a plurality of compounds represented by the formula (2).

In the formula, R ² is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is —O—, —S—, —COO—, —OCO—, —CH═. CH—, —CF═CF— or —C≡C— may be substituted, and —CH ₂ — in the alkyl and in the alkyl may be —O—, —S—, —COO—, —OCO—, At least one hydrogen in the group replaced by —CH═CH—, —CF═CF— or —C≡C— may be replaced by halogen or alkyl having 1 to 3 carbon atoms; ring A ²¹ , ring A ²² , ring A ²³ , ring A ²⁴ , and ring A ²⁵ are independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, one or two. 1,4-phenyle in which two hydrogens are replaced by fluorine Two hydrogen is replaced by, respectively fluorine and chlorine 1,4-phenylene, pyridine-2,5-diyl, ^{pyrimidine-2,5-diyl; Z 21, Z 22, Z} 23, Z 24, Z ²⁵ and Z ²⁶ are independently a single bond or —CF ₂ O—; L ²¹ , L ²² and L ²³ are independently hydrogen or fluorine; X ² is fluorine, chlorine, —CF ₃ , or —OCF ₃ ; n21, n22, n23, n24, and n25 are independently 0 or 1, and 2 ≦ n21 + n22 + n23 + n24 + n25 ≦ 3.

R ² in formula (2) is an alkyl having 1 to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl having 2 to 12 carbons, or a carbon having 2 to 12 carbons in which at least one hydrogen is replaced with fluorine. Are preferred.

From the viewpoint of stability of the compound and large dielectric anisotropy, ring A ²¹ , ring A ²² , ring A ²³ , ring A ²⁴ and ring A ²⁵ in formula (2) are 1,4-phenylene, one Alternatively, 1,4-phenylene in which two hydrogens are replaced by fluorine is preferable.

Z ²¹ , Z ²² , Z ²³ , Z ²⁴ , Z ²⁵ and Z ²⁶ in the formula (2) are all preferably a single bond or at least one is —CF ₂ O—, and other liquid crystal compounds When importance is attached to the compatibility, at least one of them is preferably —CF ₂ O—.
In formula (2), it is particularly preferable that n24 = 1 and that Z ²⁵ is —CF ₂ O—.

X ² in the formula (2) is fluorine, chlorine, —CF ₃ , —CHF ₂ , —CH ₂ F, —OCF ₃ , —OCHF ₂ , —OCH ₂ F, —OCF ₂ CFHCF ₃ or —CH═CHCF _3. And preferably fluorine, chlorine, —CF ₃ and —OCF ₃ .
In formula (2), the compound of n21 + n22 + n23 + n24 + n25 = 2 has a high clearing point, and the compound of n21 + n22 + n23 + n24 + n25 = 1 has a low melting point.
When R ^2A in formula (2) is alkenyl, the preferred configuration conforms to the preferred configuration of —CH═CH— in R ¹ of formula (1).
Since the bonding groups Z ^{21 to} Z ²⁶ in the formula (2) are a single bond or —CF ₂ O—, they are chemically relatively stable and relatively hardly deteriorated. Further, when the bonding group is a single bond, the viscosity is small. Further, when the bonding group is —CF ₂ O—, the dielectric anisotropy is large.
When the right terminal group X ² in the formula (2) is fluorine, chlorine or —OCF ₃ , the compatibility with other liquid crystal compounds at low temperature is excellent, and when it is —CF ₃ , the driving voltage lowering effect Is big.

（式中、Ｒ^２Ａは、炭素数１〜１２のアルキル、炭素数１〜１２のアルコキシ、炭素数２〜１２のアルケニル、または少なくとも１以上の水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
Ｚ^２１、Ｚ^２２、Ｚ^２３、Ｚ^２４、Ｚ^２５、およびＺ^２６はそれぞれ独立して、単結合または−ＣＦ_２Ｏ−であり；
式（２−１）中のｎ２２、ｎ２３、ｎ２４およびｎ２５は独立して、０または１であり、ｎ２２＋ｎ２３＋ｎ２４＋ｎ２５は１〜２の整数である。
Ｘ^２Ａはフッ素、塩素、−ＣＦ_３および−ＯＣＦ_３であり；
（Ｆ）はそれぞれ独立して水素またはフッ素を表す。） In Compound 2, it is preferable to use the compound of Formula (2-1).

(In the formula, R ^2A is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or C 2-12 having at least one hydrogen substituted with fluorine. Is alkenyl;
Z ²¹ , Z ²² , Z ²³ , Z ²⁴ , Z ²⁵ , and Z ²⁶ are each independently a single bond or —CF ₂ O—;
In formula (2-1), n22, n23, n24 and n25 are each independently 0 or 1, and n22 + n23 + n24 + n25 is an integer of 1 to 2.
X ^2A is fluorine, chlorine, —CF ₃ and —OCF ₃ ;
(F) each independently represents hydrogen or fluorine. )

In R ^{2A in} formula (2) and formula (2-1) and alkenyl in Z ^{21 to} Z ²⁶ , the preferred configuration of —CH═CH— is —CH═CH— in R ¹ of formula (1). According to the preferred configuration of

Z ²¹ , Z ²² , Z ²³ , Z ²⁴ , Z ^25, and Z ²⁶ are each independently a single bond or —CF ₂ O—, and when compatibility with other liquid crystal compounds is important, Z ^At least one of ²¹ , Z ²² , Z ²³ , Z ²⁴ , Z ²⁵ and Z ²⁶ is preferably —CF ₂ O—.
In formula (2-1), it is particularly preferable that n24 = 1 and that Z ²⁵ is —CF ₂ O—.

（式中、Ｒ^２Ａ，Ｚ^２１〜Ｚ^２６、Ｘ^２Ａおよび（Ｆ）の定義は式（２−１）と同じである） In compound 2, it is more preferable to use compounds represented by formulas (2-1-1) to (2-1-5).

(In the formula, the definitions of R ^2A , Z ^{21 to} Z ²⁶ , X ^2A and (F) are the same as those in formula (2-1)).

（上記式中、Ｒ^２Ａ、（Ｆ）、およびＸ^２Ａの定義は式（２−１）と同じである） In the case of using the compounds of formulas (2-1-1) to (2-1-5) as the compound 2, the following formulas (2-1-1-1) to (2-1-1-3), ( (2-1-2-1) to (2-1-2-3), (2-1-3-1) to (2-1-3-3), (2-1-4-1) to (2-1) 2-1-4-3) or a compound represented by (2-1-5-1) to (2-1-5-3) is preferably used, and the compound represented by the formula (2-1-1-1) , (2-1-1-2), formulas (2-1-2-1), (2-1-2-2), formulas (2-1-3-1), (2-1-3- It is more preferable to use a compound represented by 2), (2-1-4-2), (2-1-4-3) or (2-1-5-3).

(In the above formula, the definitions of R ^2A , (F), and X ^2A are the same as those in formula (2-1)).

  Among these compounds, compound 2 is represented by the formula (2-1-1-2), (2-1-2-1), (2-1-3-1), (2-1-3-2) , (2-1-4-2) or (2-1-4-3) is preferred.

Compound 2 has good compatibility, large dielectric anisotropy and large refractive index anisotropy.
The total amount of Compound 2 is preferably 0.5% to 70% by weight, more preferably 5% to 60% by weight, more preferably 10% to 50% by weight based on the total weight of the achiral component T. % Content is particularly preferable.

2-2-2 Properties of Compound 2 Compound 2 has a chlorobenzene ring. Compound 2 is extremely physically and chemically stable under the conditions under which the device is normally used, and has good compatibility with other liquid crystal compounds. Furthermore, it is difficult to develop a smectic phase. A composition containing this compound is stable under conditions in which the device is normally used.

  A compound having the desired physical properties can be obtained by appropriately selecting the type of ring structure, terminal group, bonding group and the like in formula (2).

2-3-1 Compound 3
The achiral component of the present invention may further contain at least one compound 3 represented by the formula (3) in addition to the compound 1. That is, the present invention includes a case where the achiral component T is composed of one compound as the compound 3 and a case where the compound 3 includes a plurality of compounds represented by the formula (3). For example, the liquid crystal composition of the present invention may contain one or more selected from the group consisting of compounds 4 to 7 in addition to compound 1 and compound 3.

In formula (3), R ³ is as described above, but the preferred configuration of —CH═CH— of alkenyl in R ³ is the preferred configuration of —CH═CH— in R ¹ of formula (1). Follow.

In formula (3), Z ³¹ , Z ³² and Z ³³ are each independently a single bond, —COO— or —CF ₂ O—, but at least one is —CF ₂ O—. Preferred examples of Z ³¹ , Z ³² and Z ³³ are a single bond or —CF ₂ O—.

In formula (3), L ³¹ , L ³² , L ³³ , L ³⁴ and L ³⁵ are independently hydrogen or fluorine. When Z ³² is —COO— or —CF ₂ O—, L ³² , L ³⁴ and L ³⁵ are preferably fluorine, and when Z ³³ is —COO— or —CF ₂ O— L ³³ , L ³⁴ and L ³⁵ are preferably fluorine.

As specific examples of alkyl in which one or more hydrogens in X ³ of formula (3) are replaced by halogen, —CH ₂ F, —CHF ₂ , —CF ₃ , — (CH ₂ ) ₂ —F, —CF ₂ CH ₂ F, —CF ₂ CHF ₂ , —CH ₂ CF ₃ , —CF ₂ CF ₃ , — (CH ₂ ) ₃ —F, — (CF ₂ ) ₃ —F, —CF ₂ CHFCF ₃ , —CHFCF _{2 CF 3, - (CH 2)} 4 -F, - (CF 2) 4 -F, - (CH 2) 5 -F, and - _{(CF 2)} 5 -F and the like.
Specific examples of alkoxy in which one or more hydrogens are replaced by halogen include —OCH ₂ F, —OCHF ₂ , —OCF ₃ , —O— (CH ₂ ) ₂ —F, —OCF ₂ CH ₂ F, — _{OCF 2 CHF 2, -OCH 2 CF} 3, -O- (CH 2) 3 -F, -O- (CF 2) 3 -F, -OCF 2 CHFCF 3, -OCHFCF 2 CF 3, -O (CH 2 ) ₄ -F, -O- (CF ₂ ) ₄ -F, -O- (CH ₂ ) ₅ -F, and -O- (CF ₂ ) ₅ -F.
Specific examples of alkenyl in which one or more hydrogen is replaced by _{halogen, -CH = CHF, -CH = CF} 2, -CF = CHF, -CH = CHCH 2 F, -CH = CHCF 3, - (CH _{2) 2 -CH = CF 2,} -CH 2 CH = CHCF 3, is -CH = CHCF _3, and -CH = CHCF ₂ CF ₃ and the like.

In formula (3), X ³ is preferably fluorine, chlorine, —CF ₃ , —CHF ₂ , —OCF ₃ or —OCHF _{2, and} more preferably fluorine, chlorine, —CF ₃ or —OCF ₃ .

（式中、Ｒ^３Ａはそれぞれ独立して、炭素数１〜１２のアルキル、炭素数１〜１２のアルコキシ、炭素数２〜１２のアルケニルまたは少なくとも１つの水素がフッ素で置き換えられてもよい炭素数２〜１２のアルケニルであり；
Ｌ^３１〜Ｌ^３５はそれぞれ独立して水素またはフッ素であり；
Ｘ^３Ａはフッ素、塩素、−ＣＦ_３、または−ＯＣＦ_３である。）

（上記式中、Ｒ^３Ａは独立して、炭素数１〜１２のアルキル、炭素数１〜１２のアルコキシ、炭素数２〜１２のアルケニルまたは少なくとも１以上の水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
Ｘ^３Ａはフッ素、塩素、−ＣＦ_３または−ＯＣＦ_３である。） In compound 3, it is preferable to use compounds represented by formulas (3-1) to (3-3), and it is more preferable to use compounds represented by formulas (3-2) and (3-3). . In the compound represented by the formula (3-2), it is more preferable to use a compound represented by the formula (3-2A) to (3-2H), and the formula (3-2A) to (3-2D). It is particularly preferable to use a compound represented by formula (3-2A) and (3-2C), and it is most preferable to use a compound represented by formula (3-2A). In the compound represented by the formula (3-3), it is more preferable to use compounds represented by the formulas (3-3A) to (3-3D), and the formulas (3-3A) and (3-3C) It is particularly preferable to use a compound represented by formula (3-3A), and it is most preferable to use a compound represented by formula (3-3A).

(Wherein R ^3A each independently represents alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons or at least one hydrogen in which at least one hydrogen may be replaced by fluorine) 2 to 12 alkenyl;
L ^{31 to} L ³⁵ are each independently hydrogen or fluorine;
X ^3A is fluorine, chlorine, —CF ₃ , or —OCF ₃ . )

(In the above formula, R ^3A is independently an alkyl having 1 to 12 carbon atoms, an alkoxy having 1 to 12 carbon atoms, an alkenyl having 2 to 12 carbon atoms, or a carbon number having at least one hydrogen atom replaced with fluorine. -12 alkenyl;
X ^3A is fluorine, chlorine, —CF ₃ or —OCF ₃ . )

Compound 3 has a relatively high clearing point, and has a large dielectric anisotropy and a large refractive index anisotropy.
The total amount of Compound 3 is preferably 0.5% to 70% by weight, more preferably 5% to 60% by weight, more preferably 10% to 50% by weight based on the total weight of the achiral component T. % Content is particularly preferred.

2-3-2 Properties of Compound 3 Compound 3 has four benzene rings and at least one —CF ₂ O— linking group. Compound 3 is extremely physically and chemically stable under the conditions under which the device is normally used, and has good compatibility with other liquid crystal compounds. A composition containing this compound is stable under conditions in which the device is normally used.

By appropriately selecting the left terminal group R ³ in formula (3), the groups on the benzene ring (L ^{31 to} L ³⁵ and X ³ ), or the linking groups Z ^{31 to} Z ³³ , the clearing point and the refractive index anisotropic It is possible to arbitrarily adjust physical properties such as property and dielectric anisotropy. The effect of the type of the left terminal group R ³ , groups on the benzene ring (L ^{31 to} L ³⁵ and X ³ ), or the linking groups Z ^{31 to} Z ^{33 on} the physical properties of the compound (3) will be described below.

When R ³ in formula (3) is alkenyl, the preferred configuration of —CH═CH— in alkenyl conforms to the preferred configuration of —CH═CH— in R ¹ of formula (1).

When the bonding groups Z ³¹ , Z ³² and Z ³³ in the formula (3) are single bonds or —CF ₂ O—, the viscosity is small. When Z ³¹ , Z ³² and Z ³³ are —CF ₂ O—, the dielectric anisotropy is large. When Z ³¹ , Z ³² and Z ³³ in the formula (3) are a single bond or —CF ₂ O—, they are chemically relatively stable and relatively difficult to deteriorate.

Equation (3) is the right terminal group ^{X 3} in fluorine, _{chlorine, -SF 5, -CF 3, -CHF} 2, -CH 2 F, -OCF 3, dielectric constant when it is -OCHF ₂ or -OCH ₂ F Large anisotropy. When X ³ is fluorine, —OCF ₃ , or —CF ₃ , it is chemically stable.

In Formula (3), when the number of fluorines in L ^{31 to} L ³⁵ is large, the dielectric anisotropy is large. When L ³¹ is hydrogen, the compatibility with other liquid crystals is excellent. When both L ³⁴ and L ³⁵ are fluorine, the dielectric anisotropy is particularly large.

  As described above, a compound having desired physical properties can be obtained by appropriately selecting the type of terminal group, bonding group, and the like.

2-4-1 Compound 4
The achiral component of the present invention may further contain at least one compound 4 represented by the formula (4) in addition to the compound 1. That is, the present invention includes a case where the achiral component T is composed of one compound as the compound 4 and a case where the compound 4 includes a plurality of compounds represented by the formula (4). In addition, for example, the liquid crystal composition of the present invention may contain one or more selected from the group consisting of compounds 2, 3 and 5-7 in addition to compound 1 and compound 4.

R ⁴ in Formula (4) is an alkyl having 1 to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl having 2 to 12 carbons, or a carbon having 2 to 12 carbons in which at least one hydrogen is replaced with fluorine. Of alkenyl. Desirable R ⁴ in formula (4) is alkyl having 1 to 12 carbons for increasing the stability to ultraviolet light or for the stability to heat. R ⁴ in formula (4) is preferably an alkenyl having 2 to 12 carbons from the viewpoint of decreasing the viscosity, and an alkyl having 1 to 12 carbons from the viewpoint of increasing the stability to ultraviolet light or the stability to heat. Is preferred.

Preferred alkyl for R ⁴ in formula (4) is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl, and more preferred alkyl is ethyl, propyl, butyl, pentyl for decreasing the viscosity. Or heptyl.

Preferred alkoxy for R ⁴ in formula (4) is methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, or heptyloxy, and more preferred alkoxy is methoxy or ethoxy for decreasing the viscosity.

Preferred alkenyl for R ⁴ in the formula (4) is vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl. 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, or 5-hexenyl, and more preferred alkenyl is vinyl, 1-propenyl, 3-butenyl, or 3-pentenyl for decreasing the viscosity. is there.
The preferred configuration of —CH═CH— in alkenyl at R ⁴ in formula (4) is in accordance with the preferred configuration of —CH═CH— in R ¹ of formula (1). In order to reduce the viscosity, trans is preferable in alkenyl such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl, 3-pentenyl and 3-hexenyl. Cis is preferable in alkenyl such as 2-butenyl, 2-pentenyl and 2-hexenyl. In these alkenyl, linear alkenyl is preferable to branched chain.

Preferable examples of alkenyl in which at least one hydrogen is replaced by fluorine in R ⁴ in the formula (4) include 2,2-difluorovinyl, 3,3-difluoro-2-propenyl, 4,4-difluoro- 3-butenyl, 5,5-difluoro-4-pentenyl, and 6,6-difluoro-5-hexenyl are used to reduce the viscosity of the liquid crystal composition. 2,2-difluorovinyl, and 4 , 4-difluoro-3-butenyl is preferred.

The alkyl in R ⁴ in formula (4) does not include cyclic alkyl. Alkoxy does not include cyclic alkoxy. Alkenyl does not include cyclic alkenyl. Alkenyl in which at least one hydrogen is replaced with fluorine does not include cyclic alkenyl in which at least one hydrogen is replaced with fluorine.
N41 in formula (4) is 1, 2, 3 or 4, provided that when n41 is 3 or 4, at least one Z ⁴¹ is —CF ₂ O— or —OCF ₂ —, and n41 is In the case of 3, all of the rings B are not 1,4-phenylene substituted with fluorine.

  Ring B in formula (4) is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 3,5 -Difluoro-1,4-phenylene, 3,5-dichloro-1,4-phenylene, or pyrimidine-2,5-diyl, and when n41 is 2 or more, at least two of the rings B are the same It may or may not be. Ring B in formula (4) is 1,4-phenylene, 3-fluoro-1,4-phenylene or 3,5-difluoro-1,4-phenylene for increasing the optical anisotropy, and lowers the viscosity. Therefore, 1,4-cyclohexylene is preferred.

Z ⁴¹ in formula (4) is independently a single bond, ethylene, —COO—, —OCO—, —CF ₂ O— or —OCF ₂ —, provided that when n41 is 3 or 4, One Z ⁴¹ is —CF ₂ O—. When n41 is 2 or more, each Z ⁴¹ may be the same or different. Z ⁴¹ in formula (4) is preferably a single bond for decreasing the viscosity. Z ⁴¹ in formula (4) is preferably —CF ₂ O— in order to increase the dielectric anisotropy and to improve the compatibility.

L ⁴⁸ and L ⁴⁹ in the formula (4) are independently hydrogen or fluorine. In order to increase the dielectric anisotropy, both L ⁴⁸ and L ⁴⁹ are preferably fluorine, and in order to increase the clearing point, L ⁴⁸ And L ⁴⁹ is preferably hydrogen.

X ⁴ in the formula (4) is fluorine, chlorine, —CF ₃ or —OCF ₃ . In order to increase the dielectric anisotropy, —CF ₃ is preferable, fluorine and —OCF ₃ are preferable to improve the compatibility, and chlorine is preferable to increase the refractive index anisotropy.

In compound 4, it is preferable to use compounds represented by formulas (4-1) to (4-10).

In the above formulas (4-1) to (4-10), R ^4A is independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or at least one Hydrogen is alkenyl having 2 to 12 carbon atoms replaced by fluorine, X ^4A is fluorine, chlorine, —CF ₃ , —OCF ₃ , and L ^{40 to} L ⁴⁹ are independently hydrogen or fluorine.
(4-1) to (4-4) have a high clearing point and excellent compatibility as a 5-ring. (4-5) to (4-7) have a high clearing point, Δn is large, and (4-8) to (4-10) are excellent in compatibility. In L ^{40 to} L ⁴⁹ , the greater the number of fluorines, the greater the dielectric anisotropy.
Compound 4 is suitable for the preparation of a composition having a large dielectric anisotropy or good compatibility at low temperatures. The total amount of compound 4 is preferably 5 to 40% by weight, more preferably 5 to 30% by weight, even more preferably 5 to 20% by weight, based on the total weight of the achiral component T. It is particularly preferable to do this.

（式（５）中、Ｒ^５は水素または炭素数１〜２０のアルキルであり、当該アルキル中の少なくとも１つの−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられてもよく、当該アルキル中の少なくとも１つの−ＣＨ_２−ＣＨ_２−は−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられもよく、当該アルキル中の少なくとも１つの水素はフッ素または塩素で置き換えられてもよく、ただし、Ｒ^５において−Ｏ−と−ＣＨ＝ＣＨ−および−ＣＯ−と−ＣＨ＝ＣＨ−が隣接することはなく；
（Ｆ）はそれぞれ独立して、水素またはフッ素であり；
Ｘ^５は水素、ハロゲン、−ＳＦ_５または炭素数１〜１０のアルキルであり、当該アルキル中の少なくとも１つの−ＣＨ_２−は−Ｏ−、−Ｓ−、−ＣＯＯ−または−ＯＣＯ−で置き換えられてもよく、当該アルキル中および当該アルキル中の−ＣＨ_２−が−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられた基中の少なくとも１つの−ＣＨ_２−ＣＨ_２−が−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられもよく、当該アルキル中、当該アルキル中の−ＣＨ_２−が−Ｏ−、−Ｓ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられた基中および当該アルキル中の少なくとも１つの−ＣＨ_２−ＣＨ_２−が−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−または−Ｃ≡Ｃ−で置き換えられた基中の少なくとも１つの水素はフッ素または塩素で置き換えられてもよく、ただし、Ｘ^５において−Ｏ−と−ＣＨ＝ＣＨ−とが隣接することはなく、−ＣＯ−と−ＣＨ＝ＣＨ−とが隣接することはない。） 2-5-1 Compound 5
In addition to compound 1, the achiral component of the present invention may further contain at least one compound 5 represented by formula (5). That is, the present invention includes a case where the achiral component T is composed of one compound as the compound 5 and a case where the compound 5 includes a plurality of compounds represented by the formula (5). In addition, for example, the liquid crystal composition of the present invention may contain one or more selected from the group consisting of compounds 2 to 4, 6 and 7 in addition to compound 1 and compound 5.

(In the formula (5), R ⁵ is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, and at least one in the alkyl. Two hydrogens may be replaced by fluorine or chlorine provided that in R ⁵ -O- and -CH = CH- and -CO- and -CH = CH- are not adjacent;
(F) is each independently hydrogen or fluorine;
X ⁵ is hydrogen, halogen, —SF ₅ or alkyl having 1 to 10 carbons, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And —CH ₂ — in the alkyl and in the alkyl may be —O—, —S—, —COO—, —OCO—, —CH═CH—, —CF═CF— or —C≡C. - in _-CH 2 of at least one of the replaced group -CH ₂ - is -CH = CH -, - CF = CF- or -C≡C- may be replaced by, in said alkyl, in the alkyl At least in a group in which —CH ₂ — is replaced by —O—, —S—, —COO—, —OCO—, —CH═CH—, —CF═CF— or —C≡C— and in the alkyl One —CH ₂ —CH ₂ — is —CH═C At least one hydrogen in the group replaced with H—, —CF═CF— or —C≡C— may be replaced with fluorine or chlorine, provided that in X ⁵ —O— and —CH═CH— Are not adjacent to each other, and —CO— and —CH═CH— are not adjacent to each other. )

In R ⁵ in formula (5), the preferred configuration of —CH═CH— in alkenyl conforms to the preferred configuration of —CH═CH— in R ¹ of formula (1).

Specific examples of alkyl in which at least one hydrogen is replaced by fluorine in R ⁵ and X ⁵ in formula (5) are —CHF ₂ , —CF ₃ , —CF ₂ CH ₂ F, —CF ₂ CHF. _{2, -CH 2 CF 3, -CF} 2 CF 3, - (CH 2) 3 -F, - (CF 2) 3 -F, -CF 2 CHFCF 3, and a -CHFCF ₂ CF _3.

Specific examples of alkoxy in which at least one hydrogen is replaced with fluorine in R ⁵ and X ⁵ in formula (5) are —OCHF ₂ , —OCF ₃ , —OCF ₂ CH ₂ F, —OCF ₂ CHF. _2, -OCH ₂ CF _3, is _{-O- (CF 2) 3 -F,} -OCF 2 CHFCF 3, and -OCHFCF ₂ CF _3.

In ^{R 5} and ^{X 5} in Formula (5), specific examples of alkenyl in which at least one hydrogen is replaced by _{fluorine, -CH = CF 2, -CF =} CHF, -CH = CHCH 2 F, - _{CH = CHCF 3, - (CH} 2) 2 -CH = CF 2, -CH 2 CH = CHCF 3, and a -CH = CHCF ₂ CF _3.

Specific examples of X ⁵ in the formula (5) include fluorine, chlorine, —CF ₃ , —CHF ₂ , —OCF ₃ and —OCHF ₂ , and fluorine, chlorine, —CF ₃ and —OCF ₃ are preferable. When X ⁵ in the formula (5) is chlorine or fluorine, the melting point of the compound 5 is relatively low, and the compatibility with other liquid crystal compounds is particularly excellent. When X ⁵ in Formula (5) is —CF ₃ , —CHF ₂ , —OCF ₃ and —OCHF ₂ , Compound 5 exhibits a relatively large dielectric anisotropy.
When X ⁵ in formula (5) is fluorine, chlorine, —SF ₅ , —CF ₃ , —OCF ₃ , or —CH═CH—CF ₃ , the dielectric anisotropy of compound 5 is relatively large, When X ⁵ is fluorine, —CF ₃ , or —OCF ₃ , it is relatively chemically stable.

（式中、Ｒ^５Ａは、炭素数１〜１２のアルキル、炭素数１〜１２のアルコキシ、炭素数２〜１２のアルケニルまたは少なくとも１つの水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
（Ｆ）はそれぞれ独立して、水素またはフッ素であり；
Ｘ^５Ａは、フッ素、塩素、−ＣＦ_３または−ＯＣＦ_３である。） In compound 5, it is preferable to use compounds represented by formulas (5-1) to (5-4), and compounds represented by (5-1) to (5-3) are more preferable. Among these compounds, the formulas (5-1-1), (5-1-2), (5-2-1) to (5-2-4), (5-3-1) or (5- The compound represented by 3-2) is particularly preferable, and the compound represented by the formula (5-2-1), (5-2-2) or (5-3-2) is most preferable.

Wherein R ^5A is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons or alkenyl having 2 to 12 carbons in which at least one hydrogen is replaced by fluorine. Yes;
(F) is each independently hydrogen or fluorine;
X ^5A is fluorine, chlorine, —CF ₃ or —OCF ₃ . )

Compound 5 is suitable for preparing a composition having a large dielectric anisotropy.
In order to increase the clearing point, it is preferable that the total amount of Compound 5 is about 1.0% by weight or more based on the total weight of the achiral component T. In order to lower the minimum temperature of the liquid crystal phase, it is preferable to contain 1 to 50% by weight of Compound 5 in total with respect to the total weight of the achiral component T. Furthermore, it is preferable to contain 1 to 25 weight% of the compound 5 with respect to the total weight of the achiral component T, and it is more preferable to contain 1 to 15 weight%.

2-5-2 Properties of Compound 5 Compound 5 has a dioxane ring and three benzene rings. Compound 5 is physically and chemically very stable under the conditions under which the device is normally used, and has a relatively good compatibility with other liquid crystal compounds despite its high clearing point. The composition containing compound 5 is stable under conditions in which the device is normally used. Therefore, the composition containing the compound 5 can expand the temperature range of the optically isotropic liquid crystal phase and can be used as a display element in a wide temperature range. Compound 5 is useful as a component for lowering the driving voltage of a composition driven in an optically isotropic liquid crystal phase. When a blue phase is expressed in the composition of a preferred embodiment including the chiral agent and the compound 5, a uniform blue phase without coexistence with the N * phase or the isotropic phase is obtained. Thus, the composition of the preferable aspect containing the compound 5 tends to express a uniform blue phase. When compound 5 is used, the clearing point of the liquid crystal composition tends to increase.

2-5-3 Synthesis of Compound 5 Next, synthesis of the compound (5) will be described. Compound (5) can be synthesized by appropriately combining known methods in organic synthetic chemistry. Methods for introducing the desired end groups, rings and linking groups into the starting materials are as follows: Organic Syntheses (John Wiley & Sons, Inc), Organic Reactions (Organic Reactions, John Wiley & Sons, Inc), Complement. It is described in Shibu Organic Synthesis (Pergamon Press), New Experimental Chemistry Course (Maruzen).

  For example, the compound of the formula (5) of the present application can be synthesized even if the method of Japanese Patent No. 2959526 (JP 2959526B) is applied mutatis mutandis.

2-6-1 Compound 6
In addition to compound 1, the achiral component of the present invention may further contain at least one compound 6 represented by formula (6). That is, the present invention includes a case where the achiral component T includes a single compound as the compound 6 and a case where the compound 6 includes a plurality of compounds represented by the formula (6). For example, the liquid crystal composition of the present invention may contain one or more selected from the group consisting of compounds 2 to 5 and 7 in addition to compound 1 and compound 6. Compound 6 is a compound having a small absolute value of dielectric anisotropy and close to neutrality.

In formula (6), r is 1, 2 or 3.
A compound in which r is 1 in the formula (6) mainly has an effect of adjusting viscosity or refractive index anisotropy, and a compound in which r is 2 or 3 in the formula (6) has a high clearing point. This has the effect of expanding the temperature range of the optically isotropic liquid crystal phase or adjusting the refractive index anisotropy value.

  When the content of the compound represented by formula (6) is increased, the driving voltage of the liquid crystal composition is increased and the viscosity is lowered. Therefore, as long as the required value of the viscosity of the liquid crystal composition is satisfied, it is contained from the viewpoint of driving voltage. Smaller amounts are desirable. The content of the compound 6 of the achiral component T is preferably 0% to 40% by weight, more preferably 1% to 40% by weight, more preferably 1% by weight with respect to the total weight of the achiral component T. It is particularly preferable to contain from 20% to 20% by weight.

R ^6A and R ^{6B in} formula (6) are each independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or at least one hydrogen being fluorine. Substituted alkenyl having 2 to 12 carbon atoms. In order to reduce the viscosity of Compound 6, R ^6A and R ^{6B in} Formula (6) are preferably alkenyl having 2 to 12 carbon atoms. In order to increase the stability to ultraviolet light or to increase the stability to heat, R ^6A and R ^{6B in} formula (6) are preferably alkyl having 1 to 12 carbon atoms.

In R ^6A and R ^6B in formula (6), alkyl is preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl. In order to reduce the viscosity, ethyl, propyl, butyl, Pentyl or heptyl is preferred.

In R ^6A and R ^6B in formula (6), alkoxy is preferably methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, or heptyloxy, and methoxy or ethoxy is preferable for decreasing the viscosity.

In R ^6A and R ^6B in formula (6), the preferred configuration of —CH═CH— in alkenyl conforms to the preferred configuration of —CH═CH— in R ¹ of formula (1).

In R ^6A and R ^6B in formula (6), alkenyl in which at least one hydrogen is replaced by fluorine is 2,2-difluorovinyl, 3,3-difluoro-2-propenyl, 4,4-difluoro-3 -Butenyl, 5,5-difluoro-4-pentenyl, and 6,6-difluoro-5-hexenyl are preferred. In order to reduce the viscosity of the composition containing compound 6, R ^6A and R ^6B are preferably 2,2-difluorovinyl and 4,4-difluoro-3-butenyl.

  Ring C and Ring D in formula (6) are independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or When 2,5-difluoro-1,4-phenylene and r is 2 or more, at least two of the rings C may be the same or different. In order to increase the optical anisotropy of compound 6, ring C and ring D are preferably 1,4-phenylene or 3-fluoro-1,4-phenylene. In order to reduce the viscosity of Compound 6, Ring C and Ring D are 1,4-cyclohexylene.

Z ⁶¹ in formula (6) is each independently a single bond, ethylene, or —COO— or —OCO—, and when r is 2 or more, at least two of the Z ⁶¹ are the same, May be different. Desirable Z ⁶¹ is a single bond for decreasing the viscosity.

これらの化合物の中でも、（６−１）〜（６−３）で表される化合物は比較的粘度が低く、（６−４）〜（６−８）で表される化合物は透明点が比較的高く、(６−９)〜(６−１３)で表される化合物は比較的透明点が高い。 In compound 6, it is preferable to use compounds represented by formulas (6-1) to (6-13).

Among these compounds, the compounds represented by (6-1) to (6-3) have a relatively low viscosity, and the compounds represented by (6-4) to (6-8) have a clear point comparison. The compounds represented by (6-9) to (6-13) have a relatively high clearing point.

  Compound 6 is used for decreasing the viscosity or increasing the clearing point as necessary. However, since the drive voltage is increased, when importance is attached to the drive voltage, it is preferably not used or used in a small amount. The total amount of compound 6 is preferably 0% to 30% by weight, more preferably 0% to 20% by weight, and particularly preferably 0% to 10% by weight.

2-7-1 Compound 7
In addition to compound 1, the achiral component of the present invention may further contain at least one compound 7 represented by formula (7). That is, the present invention includes a case where the achiral component T includes one compound as the compound 7 and a case where the compound 7 includes a plurality of compounds represented by the formula (7). For example, the liquid crystal composition of the present invention may contain one or more selected from the group consisting of compounds 2 to 6 in addition to compound 1 and compound 7.

In R ⁷ and X ⁷ in formula (7), the preferred configuration of —CH═CH— in alkenyl conforms to the preferred configuration of —CH═CH— in R ¹ of formula (1).

Specific examples of alkyl in which at least one hydrogen is replaced with fluorine at X ⁷ in formula (7) are —CHF ₂ , —CF ₃ , —CF ₂ CH ₂ F, —CF ₂ CHF ₂ , — _{CH 2 CF 3, -CF 2 CF} 3, - (CH 2) 3 -F, - (CF 2) 3 -F, -CF 2 CHFCF 3, and a -CHFCF ₂ CF _3.

Specific examples of alkoxy in which at least one hydrogen is replaced by fluorine in X ⁷ in formula (7) are —OCHF ₂ , —OCF ₃ , —OCF ₂ CH ₂ F, —OCF ₂ CHF ₂ , — OCH ₂ CF _3, is _{-O- (CF 2) 3 -F,} -OCF 2 CHFCF 3, and -OCHFCF ₂ CF _3.

In ^{X 7} in formula (7), specific examples of alkenyl in which at least one hydrogen is replaced by _{fluorine, -CH = CF 2, -CF =} CHF, -CH = CHCH 2 F, -CH = CHCF _{3, - (CH 2) 2} -CH = CF 2, -CH 2 CH = CHCF 3, and a -CH = CHCF ₂ CF _3.

In formula (7), preferred specific examples of X ⁷ include fluorine, chlorine, —CF ₃ , —CHF ₂ , —OCF ₃ and —OCHF ₂ , and fluorine, chlorine, —CF ₃ and —OCF ₃ are Further preferred.
When X ^{7 in the} formula (7) is chlorine or fluorine, the melting point of the compound 7 is relatively low, and the compatibility with other liquid crystal compounds is particularly excellent. When Formula (7) X ⁷ is —CF ₃ , —SF _5, —CHF ₂ , —OCF ₃ and —OCHF ₂ , Compound 7 exhibits a relatively large dielectric anisotropy.
When X ⁷ is fluorine, —CF ₃ , or —OCF ₃ , it is chemically stable.

（式中、Ｒ^７Ａは、炭素数１〜１２のアルキル、炭素数１〜１１のアルコキシ、炭素数２〜１２のアルケニル、または少なくとも１つの水素がフッ素で置き換えられた炭素数２〜１２のアルケニルであり；
Ｘ^７Ａは、フッ素、塩素、−ＣＦ_３または−ＯＣＦ_３である。） In the compound 7, it is preferable to use the compounds represented by the formulas (7-1) to (7-8), and the formulas (7-1-1), (7-1-2), (7-2-1) ) To (7-2-7), (7-3-1) to (7-3-4), (7-4-1), (7-5-1) or (7-5-2) It is more preferable to use a compound represented by formula (7-2-1) to (7-2-7), and it is more preferable to use a compound represented by formula (7-2-2E), The compound represented by 7-2-5-E), (7-2-2F), (7-2-5-F) or (7-2-6-F) is particularly preferable.

(Wherein R ^7A is alkyl having 1 to 12 carbons, alkoxy having 1 to 11 carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12 carbons in which at least one hydrogen is replaced by fluorine) Is;
X ^7A is fluorine, chlorine, —CF ₃ or —OCF ₃ . )

  Compound 7 is suitable for preparing a composition having a large dielectric anisotropy, and can reduce the driving voltage in the device of the present invention. It is preferable to contain 5 to 80% by weight of Compound 7 in total with respect to the total weight of the achiral component T, more preferably 20 to 75% by weight, and more preferably 30 to 70% by weight. It is particularly preferable to do this.

2-7-2 Properties of Compound 7 Compound 7 has a dioxane ring and 2 to 4 benzene rings, and has at least one —CF ₂ O— or —COO— linking group. Compound 7 is physically and chemically very stable under the conditions in which the device is normally used, and has relatively good compatibility with other liquid crystal compounds despite its high clearing point. The composition containing Compound 7 is relatively stable under conditions in which the device is normally used. Therefore, the temperature range of the optically isotropic liquid crystal phase in the composition containing the compound 7 can be expanded, and can be used as a display element in a wide temperature range. Further, the compound 7 is useful as a component for lowering the driving voltage of a composition driven with an optically isotropic liquid crystal phase. In addition, when a blue phase is expressed in a composition containing compound 7 and a chiral agent, a uniform blue phase that does not coexist with the N * phase or the isotropic phase tends to be obtained. That is, the compound 7 is a compound that easily develops a uniform blue phase. In addition, it exhibits extremely large dielectric anisotropy.

2-7-3 Synthesis of Compound 7 Compound 7 can be synthesized by appropriately combining techniques in organic synthetic chemistry. Methods for introducing the desired end groups, rings and linking groups into the starting materials are as follows: Organic Syntheses (John Wiley & Sons, Inc), Organic Reactions (Organic Reactions, John Wiley & Sons, Inc), Complement. It is described in Shibu Organic Synthesis (Pergamon Press), New Experimental Chemistry Course (Maruzen).

3 Optically Isotropic Liquid Crystal Composition The liquid crystal composition of the present invention includes an embodiment of a composition containing an achiral component T and a chiral agent and exhibiting an optically isotropic liquid crystal phase (optical isotropic). Liquid crystal composition).

3-1 Achiral component T
The achiral component T contained in the optically isotropic liquid crystal composition of the present invention includes compound 1, and optionally includes one or more selected from the group consisting of compounds 2 to 7. The achiral component T preferably includes compounds 2, 3, 5 and 7 in addition to compound 1, particularly preferably includes compounds 3 and 7, and further includes compounds 4 and 6 depending on the properties required. Can do.
Since Compound 1 has a relatively high clearing point, a relatively large dielectric anisotropy, and a relatively good compatibility at low temperature, a liquid crystal composition that exhibits optical isotropy using Compound 1 is also high. Since it exhibits a clearing point, a wide liquid crystal phase temperature range, or a large dielectric anisotropy, it is useful as a composition used in an optical element. The optically isotropic liquid crystal composition containing the compound 1 simultaneously exhibits a high clearing point and a low driving voltage.
Furthermore, in order to develop a large dielectric anisotropy, it is preferable to further add compounds represented by compounds 3 and 7. Since this composition exhibits a very large dielectric anisotropy, it is an extremely effective composition for lowering the voltage of an optical element.

これらの化合物の中でも、液晶組成物に添加されるキラル剤としては、式（Ｋ４）に含まれる式（Ｋ４−１）〜式（Ｋ４−６）、式（Ｋ５）に含まれる式（Ｋ５−１）〜式（Ｋ５−３）および式（Ｋ６）に含まれる式（Ｋ６−１）〜式（Ｋ６−６）が好ましく、式（Ｋ４−５）、式（Ｋ５−１）〜式（Ｋ５−３）および式（Ｋ６−５）〜式（Ｋ６−６）がさらに好ましい。

（式中、Ｒ^Ｋは独立して、炭素数３〜１０のアルキルまたは炭素数３〜１０のアルコキシであり、アルキル中またはアルコキシ中の少なくとも１以上の−ＣＨ_２−ＣＨ_２−は、−ＣＨ＝ＣＨ−で置き換えられてもよい。）。 3-2 Chiral Agent The chiral agent contained in the optically isotropic liquid crystal composition of the present invention is an optically active compound, and is preferably composed of a compound selected from compounds having no radical polymerizable group.
As the chiral agent used in the liquid crystal composition of the present invention, a compound having a large twisting power is preferable. A compound having a large torsional force can reduce the amount of addition necessary for obtaining a desired pitch, and therefore, an increase in driving voltage can be suppressed, which is practically advantageous. Specifically, compounds represented by formulas (K1) to (K6) are preferable. In formulas (K4) to (K6), the binaphthyl group and the octahydronaphthyl group are optically active sites, and the chirality of the chiral agent does not matter.

Among these compounds, the chiral agent added to the liquid crystal composition includes the formula (K4-1) to the formula (K4-6) included in the formula (K4) and the formula (K5−5) included in the formula (K5). 1) to formula (K5-3) and formula (K6) to formula (K6-6) included in formula (K6) are preferable, and formula (K4-5), formula (K5-1) to formula (K5) are preferable. -3) and formulas (K6-5) to (K6-6) are more preferable.

(Wherein, R ^K is independently alkyl having 3 to 10 carbons or alkoxy having 3 to 10 carbons, and at least one or more —CH ₂ —CH ₂ — in alkyl or alkoxy is —CH = CH- may be substituted).

  One compound or a plurality of compounds may be used as the chiral agent contained in the liquid crystal composition.

  In order to facilitate the development of an optically isotropic liquid crystal phase, the chiral agent is preferably contained in an amount of 1 to 40% by weight, based on the total weight of the liquid crystal composition of the present invention, and 3 to 25% by weight. It is more preferable to contain, and it is especially preferable to contain 3 to 15 weight%.

3-3 Optically isotropic liquid crystal phase In the present specification, the liquid crystal composition is optically isotropic, because the liquid crystal molecular alignment is isotropic macroscopically, and so on. Although it shows anisotropy, it means that there is a liquid crystal order microscopically. “Pitch based on the order of liquid crystal in the liquid crystal composition (hereinafter, sometimes simply referred to as“ pitch ”)” is preferably 700 nm or less, more preferably 500 nm or less, and 350 nm or less. Most preferably.

In this specification, the term “non-liquid crystal isotropic phase” is a generally defined isotropic phase, that is, a disordered phase, and even if a region where the local order parameter is not zero is generated, the cause is fluctuating. Isotropic phase that is due to. For example, an isotropic phase appearing on the high temperature side of the nematic phase corresponds to a non-liquid crystal isotropic phase in this specification. The same definition shall apply to the chiral liquid crystal in this specification.
In this specification, the “optically isotropic liquid crystal phase” means a phase that expresses an optically isotropic liquid crystal phase instead of fluctuations, and a phase that expresses a platelet structure (a blue phase in a narrow sense). Is an example.
In this specification, unless otherwise specified, a nematic phase means a nematic phase in a narrow sense that does not include a chiral nematic phase.

  In the optically isotropic liquid crystal composition of the present invention, although it is an optically isotropic liquid crystal phase, a platelet structure typical of a blue phase may not be observed under a polarizing microscope. Therefore, in this specification, a phase that develops a platelet structure is referred to as a blue phase, and an optically isotropic liquid crystal phase including the blue phase is referred to as an optically isotropic liquid crystal phase. That is, the blue phase is included in the optically isotropic liquid crystal phase.

  In general, the blue phase is classified into three types of a blue phase I, a blue phase II, and a blue phase III, and these three types of blue phases are all optically active and isotropic. In the blue phase I or blue phase II, two or more types of diffracted light caused by Bragg reflection from different lattice planes are observed. The blue phase is generally observed between the non-liquid crystal isotropic phase and the chiral nematic phase.

  The state in which the optically isotropic liquid crystal phase does not show diffracted light of two or more colors means that the platelet structure observed in the blue phase I and the blue phase II is not observed and is generally monochromatic. To do. In an optically isotropic liquid crystal phase that does not show diffracted light of two or more colors, it is not necessary until the color brightness is uniform in the plane.

An optically isotropic liquid crystal phase that does not show diffracted light of two or more colors has an advantage that the reflected light intensity due to Bragg reflection is suppressed or shifted to a lower wavelength side.
In addition, in a liquid crystal medium that reflects visible light, color may be a problem when used as a display element. However, in a liquid crystal that does not exhibit diffracted light of two or more colors, the reflection wavelength is shifted by a low wavelength. Therefore, the reflection of visible light can be eliminated at a pitch longer than the narrowly defined blue phase (phase that expresses the platelet structure).

  In the liquid crystal composition of the present invention containing the achiral component T and the chiral agent, the chiral agent is preferably added at a concentration such that the pitch is 700 nm or less. In addition, the composition which expresses a nematic phase contains the compound 1 and another component as needed.

  The optically isotropic liquid crystal composition of the present invention can also be obtained by adding a chiral agent to a composition having a chiral nematic phase and not having an optically isotropic liquid crystal phase. In addition, the composition which has a chiral nematic phase and does not have an optically isotropic liquid crystal contains the compound 1, an optically active compound, and another component as needed. At this time, in order not to develop an optically isotropic liquid crystal phase, a chiral agent is preferably added at a concentration such that the pitch is 700 nm or more. Here, the compounds (K1) to (K5), which are compounds having a large torsional force, can be used, and more preferably, the compounds of the formulas (K2-1) to (K2-8) and (K4−) are used. The compounds represented by 1) to (K4-6), formulas (K5-1) to (K5-3), or formulas (K6-1) to (K6-6) are used.

  The temperature range in which the liquid crystal composition of the preferred embodiment of the present invention exhibits an optically isotropic liquid crystal phase is a nematic phase or a liquid crystal composition having a wide coexistence temperature range of a chiral nematic phase and an isotropic phase. It can be widened by adding an optically isotropic liquid crystal phase. For example, a liquid crystal compound having a high clearing point and a liquid crystal compound having a low clearing point are mixed to prepare a liquid crystal composition having a wide coexistence temperature range of a nematic phase and an isotropic phase over a wide temperature range, and a chiral agent is added thereto. Thus, a composition that exhibits an optically isotropic liquid crystal phase in a wide temperature range can be prepared.

  As the liquid crystal composition having a wide coexistence temperature range of the nematic phase or the chiral nematic phase and the isotropic phase, the difference between the upper limit temperature and the lower limit temperature at which the chiral nematic phase and the non-liquid crystal isotropic phase coexist is 3 to 150 ° C. A liquid crystal composition is preferable, and a liquid crystal composition having a difference of 5 to 150 ° C. is more preferable. Further, a liquid crystal composition having a difference between the upper limit temperature and the lower limit temperature at which the nematic phase and the non-liquid crystal isotropic phase coexist is 3 to 150 ° C.

When an electric field is applied to the liquid crystal medium of the present invention in an optically isotropic liquid crystal phase, electric birefringence occurs, but the Kerr effect is not necessarily required.
Since the electrical birefringence in the optically isotropic liquid crystal phase increases as the pitch increases, the type and content of the chiral agent can be adjusted as long as other optical properties (transmittance, diffraction wavelength, etc.) are satisfied. Thus, the electrical birefringence can be increased by setting the pitch longer.

3-4 Other components The liquid crystal composition of the present invention is a solvent, monomer, polymer substance, polymerization initiator, antioxidant, ultraviolet absorber, as long as it does not significantly affect the properties of the composition. A curing agent, a stabilizer, a dichroic dye, a photochromic compound, and the like may be included.
Examples of the dichroic dye used in the liquid crystal composition of the present invention include merocyanine series, styryl series, azo series, azomethine series, azoxy series, quinophthalone series, anthraquinone series, and tetrazine series.

4 Optically Isotropic Polymer / Liquid Crystal Composite Material 4-1 Polymer / Liquid Crystal Composite Material The polymer / liquid crystal composite material of the present invention is a composite material containing a liquid crystal composition and a polymer, and is optically Is isotropic, and can be used for an optical element driven in an optically isotropic liquid crystal phase. The liquid crystal composition contained in the polymer / liquid crystal composite material of the present invention is the liquid crystal composition of the present invention.

  In the present specification, the “polymer / liquid crystal composite material” is not particularly limited as long as it is a composite material including both a liquid crystal composition and a polymer compound. A state where the polymer is phase-separated from the liquid crystal composition without being dissolved in a solvent or the like may be used.

  The optically isotropic polymer / liquid crystal composite material according to a preferred embodiment of the present invention can exhibit an optically isotropic liquid crystal phase in a wide temperature range. Further, the polymer / liquid crystal composite material according to a preferred embodiment of the present invention has an extremely fast response speed. Moreover, the polymer / liquid crystal composite material according to a preferred embodiment of the present invention can be suitably used for an optical element such as a display element based on these effects.

4-2 Polymer Compound The composite material of the present invention can be produced by mixing an optically isotropic liquid crystal composition and a polymer obtained by polymerization in advance, but becomes a polymer material. It is preferably produced by mixing a low molecular weight monomer, macromonomer, oligomer or the like (hereinafter collectively referred to as “monomer etc.”) and the liquid crystal composition CLC, and then performing a polymerization reaction in the mixture. In the present specification, a mixture containing a monomer or the like and a liquid crystal composition is referred to as a “polymerizable monomer / liquid crystal mixture”. The “polymerizable monomer / liquid crystal mixture” includes a polymerization initiator, a curing agent, a catalyst, a stabilizer, a dichroic dye, or a photochromic compound, which will be described later, as necessary, as long as the effects of the present invention are not impaired. But you can. For example, the polymerizable monomer / liquid crystal mixture of the present invention may contain 0.1 to 20 parts by weight of a polymerization initiator with respect to 100 parts by weight of the polymerizable monomer, if necessary. The “polymerizable monomer / liquid crystal mixture” must be a liquid crystal medium when polymerized in the blue phase, but is not necessarily a liquid crystal medium when polymerized in the isotropic phase.

  The polymerization temperature is preferably a temperature at which the polymer / liquid crystal composite material exhibits high transparency and isotropic properties. More preferably, the polymerization is terminated at a temperature at which the mixture of the monomer and the liquid crystal material develops an isotropic phase or a blue phase, and at the isotropic phase or the optically isotropic liquid crystal phase. That is, after polymerization, the polymer / liquid crystal composite material is preferably set to a temperature that does not substantially scatter light on the longer wavelength side than visible light and develops an optically isotropic state.

For example, low molecular weight monomers, macromonomers, and oligomers can be used as the polymer raw materials constituting the composite material of the present invention. In this specification, the high molecular weight raw material monomers are low molecular weight monomers, macromonomers. , Used to include oligomers and the like. In addition, it is preferable that the obtained polymer has a three-dimensional crosslinked structure. Therefore, it is preferable to use a polyfunctional monomer having two or more polymerizable functional groups as a raw material monomer for the polymer. The polymerizable functional group is not particularly limited, and an acrylic group, a methacryl group, a glycidyl group, an epoxy group, an oxetanyl group, a vinyl group, and the like can be raised, but an acrylic group and a methacryl group are preferable from the viewpoint of polymerization rate. When a monomer having two or more polymerizable functional groups in the polymer raw material monomer is contained in an amount of 10% by weight or more, high transparency and isotropy are easily exhibited in the composite material of the present invention. This is preferable.
In order to obtain a suitable composite material, the polymer preferably has a mesogen moiety, and a raw material monomer having a mesogen moiety can be used as a part or all of the polymer as a polymer raw material monomer.

4-2-1 Monofunctional / bifunctional monomer / trifunctional monomer having mesogen moiety The monofunctional or bifunctional monomer having a mesogen moiety is not particularly limited in terms of structure, but for example, the following formula (M1) Alternatively, a compound represented by the formula (M2) can be given. R ^a -Y- (A ^M -Z ^M ) _m1 -A ^M -Y-R ^b (M1)
_{^{R b -Y- (A M -Z M}} ) m1 -A M -Y-R b (M2)

In formula (M1), R ^a is hydrogen, halogen, —C≡N, —N═C═O, —N═C═S, or alkyl having 1 to 20 carbons, and in these alkyls, at least 1 Two —CH ₂ — may be replaced by —O—, —S—, —CO—, —COO—, or —OCO—, and at least one —CH ₂ —CH ₂ — in the alkyl is — CH═CH—, —CF═CF—, or —C≡C— may be substituted, and in these alkyl groups, at least one —CH ₂ — in the alkyl is —O—, —S—, -COO-, or during replaced group by -OCO-, or at least one _-CH 2 -CH ₂ in the alkyl - at least in groups are replaced by -CH = CH- or -C≡C- One hydrogen is halogen or -C≡N It may be replaced come. R ^b is each independently a polymerizable group of formula (M3-1) to formula (M3-7).

Preferred R ^a is hydrogen, halogen, —C≡N, —CF ₃ , —CF ₂ H, —CFH ₂ , —OCF ₃ , —OCF ₂ H, alkyl having 1 to 20 carbons, or alkyl having 1 to 19 carbons. Alkoxy, alkenyl having 2 to 21 carbons, and alkynyl having 2 to 21 carbons. Particularly preferred R ^a is —C≡N, alkyl having 1 to 20 carbons and alkoxy having 1 to 19 carbons.

In formula (M2), R ^b is each independently a polymerizable group of formulas (M3-1) to (M3-7).

Here, R ^d in formulas (M3-1) to (M3-7) is each independently hydrogen, halogen, or alkyl having 1 to 5 carbons, and in these alkyls, at least one hydrogen is replaced with halogen. May be. Preferred R ^d is hydrogen, halogen and methyl. Particularly preferred R ^d is hydrogen, fluorine and methyl.
In addition, the formula (M3-2), formula (M3-3), formula (M3-4), and formula (M3-7) are preferably polymerized by radical polymerization. The formula (M3-1), formula (M3-5), and formula (M3-6) are preferably polymerized by cationic polymerization. In either case, polymerization starts when a small amount of radical or cationic active species is generated in the reaction system. A polymerization initiator can be used for the purpose of accelerating the generation of active species. For example, light or heat can be used to generate the active species.

In formulas (M1) and (M2), A ^M is each independently an aromatic or non-aromatic 5-membered ring, 6-membered ring, or condensed ring having 9 or more carbon atoms. CH ₂ — may be —O—, —S—, —NH—, or —NCH ₃ —, and —CH═ in the ring may be replaced with —N═, the hydrogen atom on the ring is halogen, and carbon number It may be replaced with 1 to 5 alkyl or halogenated alkyl. Specific examples of preferred ^{A M} are 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, naphthalene-2,6-diyl, tetrahydronaphthalene-2,6-diyl, fluorene -2, 7-diyl, or bicyclo [2.2.2] octane-1,4-diyl, in which at least one —CH ₂ — may be replaced by —O— and at least one —CH = May be replaced by -N =, and in these rings, at least one hydrogen may be replaced by halogen, alkyl having 1 to 5 carbon atoms or alkyl halide having 1 to 5 carbon atoms.
In consideration of the stability of the compound, —CH ₂ —O—CH ₂ —O— in which oxygen and oxygen are not adjacent to each other than —CH ₂ —O—O—CH ₂ — in which oxygen and oxygen are adjacent to each other Is preferred. The same applies to sulfur.

Among these, particularly preferred ^{A M,} 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4 -Phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 2-methyl-1,4-phenylene, 2-trifluoromethyl-1,4-phenylene, 2 , 3-bis (trifluoromethyl) -1,4-phenylene, naphthalene-2,6-diyl, tetrahydronaphthalene-2,6-diyl, fluorene-2,7-diyl, 9-methylfluorene-2,7- Diyl, 1,3-dioxane-2,5-diyl, pyridine-2,5-diyl, and pyrimidine-2,5-diyl. The steric configuration of 1,4-cyclohexylene and 1,3-dioxane-2,5-diyl is preferably trans rather than cis.
Since 2-fluoro-1,4-phenylene is structurally identical to 3-fluoro-1,4-phenylene, the latter was not exemplified. This rule also applies to the relationship between 2,5-difluoro-1,4-phenylene and 3,6-difluoro-1,4-phenylene.

In formulas (M1) and (M2), each Y is independently a single bond or alkylene having 1 to 20 carbon atoms, and in these alkylenes, at least one —CH ₂ — is —O— or —S—. At least one —CH ₂ —CH ₂ — in the alkyl may be replaced with —CH═CH—, —C≡C—, —COO—, or —OCO—. Preferred Y is a single bond, — (CH ₂ ) _m2 —, —O (CH ₂ ) _m2 —, and — (CH ₂ ) _m2 O— (wherein m2 is an integer of 1 to 20). . Particularly preferred Y is a single bond, — (CH ₂ ) _m2 —, —O (CH ₂ ) _m2 —, and — (CH ₂ ) _m2 O— (wherein m2 is an integer of 1 to 10). is there. In consideration of the stability of the compound, —Y—R ^a and —Y—R ^b are in their groups —O—O—, —O—S—, —S—O—, or —S—S. It is preferable not to have −.

In formulas (M1) and (M2), Z ^M is each independently a single bond, — (CH ₂ ) _m3 —, —O (CH ₂ ) _m3 —, — (CH ₂ ) _m3 O—, —O ( CH ₂ ) _{m 3} O—, —CH═CH—, —C≡C—, —COO—, —OCO—, — (CF ₂ ) ₂ —, — (CH ₂ ) ₂ —COO—, —OCO— (CH ₂ ) ₂ —, —CH═CH—COO—, —OCO—CH═CH—, —C≡C—COO—, —OCO—C≡C—, —CH═CH— (CH ₂ ) ₂ —, — (CH ₂ ) ₂ —CH═CH—, —CF═CF—, —C≡C—CH═CH—, —CH═CH—C≡C—, —OCF ₂ — (CH ₂ ) ₂ —, — ( _{CH 2) 2 -CF 2 O -} , - is or _-CF 2 O-(in the formula, m3 is an integer of 1~20) - OCF _2.

Preferred Z ^M is a single bond, — (CH ₂ ) _{m 3} —, —O (CH ₂ ) _{m 3} —, — (CH ₂ ) _{m 3} O—, —CH═CH—, —C≡C—, —COO—, — _{OCO -, - (CH 2)} 2 -COO -, - OCO- (CH 2) 2 -, - CH = CH-COO -, - OCO-CH = CH -, - OCF 2 -, and _-CF 2 O- It is.

In formulas (M1) and (M2), m1 is an integer of 1 to 6. Preferred m1 is an integer of 1 to 3. When m1 is 1, it is a bicyclic compound having two rings such as a 6-membered ring. When m1 is 2 or 3, they are tricyclic and tetracyclic compounds, respectively. For example, when m1 is 1, two A ^M may be may be the same or different. For example, when m1 is 2, three A ^M (or two Z ^M ) may be the same or different. The same applies when m1 is 3-6. The same applies to R ^a , R ^b , R ^d , Z ^M , A ^M and Y.

The compound (M1) represented by the formula (M1) and the compound (M2) represented by the formula (M2) contain isotopes such as ² H (deuterium) and ¹³ C in an amount larger than the natural abundance. However, since it has the same characteristics, it can be preferably used.

More preferred examples of the compound (M1) and the compound (M2) are the compounds (M1-1) represented by the formulas (M1-1) to (M1-41) and the formulas (M2-1) to (M2-27). To (M1-41) and compounds (M2-1) to (M2-27). In these compounds, the definitions of R ^a , R ^b , R ^d , Z ^M , A ^M , Y and p are the same as those in formula (M1) and formula (M2) described in the embodiments of the present invention.

The following partial structures of the compounds (M1-1) to (M1-41) and (M2-1) to (M2-27) will be described. The partial structure (a1) represents 1,4-phenylene in which at least one hydrogen is replaced by fluorine. The partial structure (a2) represents 1,4-phenylene in which at least one hydrogen may be replaced by fluorine. The partial structure (a3) represents 1,4-phenylene in which at least one hydrogen may be replaced with either fluorine or methyl. The partial structure (a4) represents fluorene in which the hydrogen at the 9-position may be replaced with methyl.

  A monomer having no mesogen moiety and a polymerizable compound other than the monomers (M1) and (M2) having a mesogen moiety can be used as necessary.

For the purpose of optimizing the optical isotropy of the polymer / liquid crystal composite material of the present invention, a monomer having a mesogenic moiety and having three or more polymerizable functional groups may be used. As a monomer having a mesogenic moiety and having three or more polymerizable functional groups, known compounds can be preferably used. For example, (M4-1) to (M4-3), and more specific examples include: Examples thereof include compounds described in JP-A No. 2000-327632 (JP 2000-327632A), JP-A No. 2004-182949 (JP 2004-182949A), JP-A No. 2004-59772 (JP 2004-59772A). However, in (M4-1) to (M4-3), R ^b , Z ^M , Y, and (F) have the same definition as described above.

4-2-2 Monomer having a polymerizable functional group not having a mesogen moiety As a monomer having a polymerizable functional group not having a mesogen moiety, for example, a linear or branched acrylate having 1 to 30 carbon atoms or carbon Examples of the monomer having 1 to 30 linear or branched diacrylates and three or more polymerizable functional groups include glycerol propoxylate (1PO / OH) triacrylate, pentaerythritol propoxylate triacrylate, penta Erythritol triacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, trimethylolpropane triacrylate, di (trimethylolpropane) tetraacrylate, pentaerythritol Tetraacrylate, di (pentaerythritol) pentaacrylate, di (pentaerythritol) hexaacrylate, there may be mentioned trimethylolpropane triacrylate, but is not limited thereto.

4-2-3 Polymerization initiator The polymerization reaction in the production of the polymer constituting the composite material of the present invention is not particularly limited. For example, photoradical polymerization, thermal radical polymerization, photocationic polymerization and the like are performed.

  Examples of radical photopolymerization initiators that can be used in radical photopolymerization include DAROCUR 1173 and 4265 (both trade names, BASF Japan Ltd.), Irgacure 184, 369, 500, 651, and 784. 819, 907, 1300, 1700, 1800, 1850, and 2959 (all are trade names, BASF Japan Ltd.).

  Examples of preferred initiators for thermal radical polymerization that can be used in thermal radical polymerization are benzoyl peroxide, diisopropyl peroxydicarbonate, t-butylperoxy-2-ethylhexanoate, t-butylperoxypivalate , T-butylperoxydiisobutyrate, lauroyl peroxide, dimethyl 2,2′-azobisisobutyrate (MAIB), di-t-butyl peroxide (DTBPO), azobisisobutyronitrile (AIBN), azobiscyclohexanecarbox Nitrile (ACN).

  Examples of the cationic photopolymerization initiator that can be used in the cationic photopolymerization are diaryliodonium salts (hereinafter referred to as “DAS”) and triarylsulfonium salts (hereinafter referred to as “TAS”).

  Examples of DAS are diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluorophosphonate, diphenyliodonium hexafluoroarsenate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium trifluoroacetate, diphenyliodonium-p-toluenesulfonate, diphenyliodoniumtetra (pentafluoro Phenyl) borate, 4-methoxyphenylphenyliodonium tetrafluoroborate, 4-methoxyphenylphenyliodonium hexafluorophosphonate, 4-methoxyphenylphenyliodonium hexafluoroarsenate, 4-methoxyphenylphenyliodonium trifluoromethanesulfonate, 4-methoxyphenyl E sulfonyl iodonium trifluoroacetate, and 4-methoxyphenyl-phenyl iodonium -p- toluenesulfonate.

  DAS can be made highly sensitive by adding a photosensitizer such as thioxanthone, phenothiazine, chlorothioxanthone, xanthone, anthracene, diphenylanthracene, and rubrene.

  Examples of TAS are triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluorophosphonate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoroacetate, triphenylsulfonium-p-toluenesulfonate , Triphenylsulfonium tetra (pentafluorophenyl) borate, 4-methoxyphenyldiphenylsulfonium tetrafluoroborate, 4-methoxyphenyldiphenylsulfonium hexafluorophosphonate, 4-methoxyphenyldiphenylsulfonium hexafluoroarsenate, 4-methoxyphenyldiphenylsulfonium trifluoride Lomethanesulfonate 4-methoxyphenyl diphenyl sulfonium trifluoroacetate, and 4-methoxyphenyl diphenyl sulfonium -p- toluenesulfonate.

  Examples of specific trade names of the photocationic polymerization initiator include Cyracure UVI-6990, Cyracure UVI-6974, Cyracure UVI-6922 (trade names, UCC Corporation, respectively), Adekaoptomer SP-150, SP-152, SP-170, SP-172 (each trade name, ADEKA Co., Ltd.), Rhodorsil Photoinitiator 2074 (trade name, Rhodia Japan Co., Ltd.), Irgacure (IRGACURE) 250 (trade name, BASF Japan Co., Ltd.) ), And UV-9380C (trade name, GE Toshiba Silicone Co., Ltd.).

4-2-4 Curing Agent In the production of the polymer constituting the composite material of the present invention, in addition to the monomer and the polymerization initiator, one or more other suitable components, for example, a curing agent Catalysts, stabilizers and the like may be added.

  As the curing agent, conventionally known latent curing agents that are usually used as curing agents for epoxy resins can be used. Examples of the latent epoxy resin curing agent include amine curing agents, novolak resin curing agents, imidazole curing agents, and acid anhydride curing agents. Examples of amine curing agents include aliphatic polyamines such as diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylaminopropylamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norbornenediamine, 1,2-diaminocyclohexane, alicyclic polyamines such as laromine, aromatics such as diaminodiphenylmethane, diaminodiphenylethane, metaphenylenediamine It is a polyamine.

  Examples of novolak resin-based curing agents are phenol novolac resins and bisphenol novolac resins. Examples of imidazole curing agents are 2-methylimidazole, 2-ethylhexylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate.

  Examples of acid anhydride curing agents are tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylcyclohexene tetracarboxylic dianhydride, phthalic anhydride, trimellitic anhydride Pyromellitic anhydride, benzophenone tetracarboxylic dianhydride.

  Moreover, you may further use the hardening accelerator for accelerating the hardening reaction of the polymeric compound which has a glycidyl group, an epoxy group, and an oxetanyl group, and a hardening | curing agent. Examples of curing accelerators are tertiary amines such as benzyldimethylamine, tris (dimethylaminomethyl) phenol, dimethylcyclohexylamine, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazole Such as imidazoles such as triphenylphosphine, quaternary phosphonium salts such as tetraphenylphosphonium bromide, dia, such as 1,8-diazabicyclo [5.4.0] undecene-7, and organic acid salts thereof. Quaternary ammonium salts such as zabicycloalkenes, tetraethylammonium bromide and tetrabutylammonium bromide, and boron compounds such as boron trifluoride and triphenylborate. These curing accelerators can be used alone or in combination.

  Also, for example, a stabilizer is preferably added to prevent undesired polymerization during storage. All compounds known to those skilled in the art can be used as stabilizers. Representative examples of the stabilizer include 4-ethoxyphenol, hydroquinone, butylated hydroxytoluene (BHT) and the like.

4-3 Composition of Polymer / Liquid Crystal Composite Material The content of the liquid crystal composition in the polymer / liquid crystal composite material of the present invention is within a range in which the composite material can express an optically isotropic liquid crystal phase. It is preferable that the content is as high as possible. This is because the electric birefringence value of the composite material of the present invention increases as the content of the liquid crystal composition is higher.

  In the polymer / liquid crystal composite material of the present invention, the content of the liquid crystal composition is preferably 60 to 99% by weight, more preferably 60% to 98% by weight, and 80% to 97% by weight with respect to the composite material. Weight percent is particularly preferred. In the polymer / liquid crystal composite material of the present invention, the polymer content is preferably 1% by weight to 40% by weight, more preferably 2% by weight to 40% by weight, more preferably 3% by weight with respect to the composite material. % To 20% by weight is particularly preferred.

5 Optical Device The optical device of the present invention comprises a liquid crystal composition or a polymer / liquid crystal composite material (hereinafter, the liquid crystal composition of the present invention and the polymer / liquid crystal composite material may be collectively referred to as a liquid crystal medium). The optical element is driven by an optically isotropic liquid crystal phase.
When no electric field is applied, the liquid crystal medium is optically isotropic, but when an electric field is applied, the liquid crystal medium exhibits optical anisotropy, and light modulation by the electric field becomes possible.
As an example of the structure of the liquid crystal display element, as shown in FIG. 1, there can be mentioned a structure in which electrodes of a comb-shaped electrode substrate are alternately arranged with electrodes 1 extending from the left side and electrodes 2 extending from the right side. When there is a potential difference between the electrode 1 and the electrode 2, on the comb-shaped electrode substrate as shown in FIG. 1, when attention is paid to one electrode, the electric fields in two directions, the upper direction and the lower direction on the drawing, Can provide a state that exists.
The liquid crystal composition of the present invention can be used for an optical element. Since the liquid crystal composition of the present invention exhibits a low driving voltage and a short response time, the optical element according to a preferred embodiment of the present invention can be driven at a low voltage and can respond at high speed.

（上記式中、Ｒ^１ａは炭素数１〜１０のアルキルであり、；
Ｘ^１ａはフッ素、塩素、−Ｃ≡Ｎ、−ＣＦ_３または−ＯＣＦ_３である。）
式（１−１）で表される化合物は、高い透明点と大きな誘電率異方性値、大きな屈折率異方性値を有し、式（１−２）で表される化合物は、比較的高い透明点、大きな誘電率異方性値、比較的良好な低温での相溶性を有する、したがって、これらの化合物は、低い駆動電圧、あるいは広い液晶相温度範囲を有する液晶組成物の成分として有用である。 6 Compound The liquid crystal compound of the present invention is a compound represented by the formulas (1-1) and (1-2)).

Compounds represented by formula (1-1) and formula (1-2).

(Wherein R ^1a is alkyl having 1 to 10 carbons;
X ^1a is fluorine, chlorine, —C≡N, —CF ₃ or —OCF ₃ . )
The compound represented by the formula (1-1) has a high clearing point, a large dielectric anisotropy value, and a large refractive index anisotropy value. The compound represented by the formula (1-2) is a comparative example. High clearing point, large dielectric anisotropy value, and relatively good compatibility at low temperatures. Therefore, these compounds are used as components of liquid crystal compositions having a low driving voltage or a wide liquid crystal phase temperature range. Useful.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited by these Examples. Unless otherwise specified, “%” means “% by weight”.
Moreover, the obtained compound was identified by the nuclear magnetic resonance spectrum obtained by < ¹ > H-NMR analysis, the gas chromatogram obtained by gas chromatography (GC) analysis, etc. The analysis method was as follows.

1) Analysis method 1-1) ¹ H-NMR analysis DRX-500 (trade name, Bruker BioSpin Co., Ltd.) was used as a measurement apparatus. The measurement was carried out by dissolving the sample produced in Examples and the like in a deuterated solvent in which a sample such as CDCl ₃ is soluble, and at room temperature under conditions of 500 MHz and 24 times of integration. In the description of the obtained nuclear magnetic resonance spectrum, s is a singlet, d is a doublet, t is a triplet, q is a quartet, and m is a multiplet. Tetramethylsilane (TMS) was used as a reference material for the zero point of the chemical shift δ value.

1-2) GC analysis As a measuring apparatus, a GC-14B gas chromatograph manufactured by Shimadzu Corporation was used. As the column, a capillary column CBP1-M25-025 (length 25 m, inner diameter 0.22 mm, film thickness 0.25 μm) manufactured by Shimadzu Corporation; dimethylpolysiloxane; nonpolar) was used as the stationary liquid phase. Helium was used as the carrier gas, and the flow rate was adjusted to 1 ml / min. The temperature of the sample vaporizing chamber was set to 300 ° C., and the temperature of the detector (FID) portion was set to 300 ° C.

The sample was dissolved in toluene to prepare a 1% by weight solution, and 1 μl of the resulting solution was injected into the sample vaporization chamber.
As a recorder, a C-R6A type Chromatopac manufactured by Shimadzu Corporation or an equivalent thereof was used. The obtained gas chromatogram shows the peak retention time and peak area value corresponding to the component compounds.

  As a sample dilution solvent, for example, chloroform or hexane may be used. In addition, as columns, Agilent Technologies Inc. capillary column DB-1 (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm), Agilent Technologies Inc. HP-1 (length 30 m, inner diameter 0) .32 mm, film thickness 0.25 μm), Rtx-1 from Restek Corporation (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm), BP-1 from SGE International Pty. Ltd (length 30 m, inner diameter) 0.32 mm, film thickness of 0.25 μm) or the like may be used.

  The area ratio of peaks in the gas chromatogram corresponds to the ratio of component compounds. In general, the weight% of the component compound of the analysis sample is not completely the same as the area% of each peak of the analysis sample. However, when the above-described column is used in the present invention, the correction factor is substantially 1. Therefore, the weight% of the component compound in the analysis sample substantially corresponds to the area% of each peak in the analysis sample. This is because there is no significant difference in the correction coefficients of the component liquid crystal compounds. In order to obtain the composition ratio of the liquid crystal compound in the liquid crystal composition more accurately by the gas chromatogram, an internal standard method based on the gas chromatogram is used. The liquid crystal compound component (test component) weighed in a certain amount accurately and the reference liquid crystal compound (reference material) are simultaneously measured by gas chromatography, and the area ratio between the peak of the obtained test component and the peak of the reference material Is calculated in advance. When correction is performed using the relative intensity of the peak area of each component with respect to the reference substance, the composition ratio of the liquid crystal compound in the liquid crystal composition can be determined more accurately from gas chromatography analysis.

1-3) Samples for measuring physical property values of liquid crystal compounds, etc. Samples for measuring physical property values of liquid crystal compounds include two types: a case where the compound itself is used as a sample, and a case where a compound is mixed with a mother liquid crystal to form a sample. .

  In the latter case using a sample in which a compound is mixed with mother liquid crystals, the measurement is performed by the following method. First, 15% by weight of the obtained liquid crystal compound and 85% by weight of the mother liquid crystal are mixed to prepare a sample. Then, an extrapolated value is calculated from the measured value of the obtained sample according to the extrapolation method based on the following calculation formula. This extrapolated value is taken as the physical property value of this compound.

<Extrapolated value> = (100 × <Measured value of sample> − <Weight% of mother liquid crystal> × <Measured value of mother liquid crystal>) / <Weight% of liquid crystal compound>

  Even if the ratio between the liquid crystal compound and the mother liquid crystal is this ratio (15% by weight: 85% by weight), when the smectic phase or crystal is precipitated at 25 ° C., the ratio between the liquid crystal compound and the mother liquid crystal is 10 Weight%: 90% by weight, 5% by weight: 95% by weight, 1% by weight: 99% by weight In order of the physical properties of the sample with a composition in which the smectic phase or crystals no longer precipitate at 25 ° C. An extrapolated value is determined according to the above formula and is used as a physical property value of the liquid crystal compound.

There are various types of mother liquid crystals used for measurement. For example, the composition (% by weight) of the mother liquid crystals A is as follows.

1-4) Measuring method of physical property value of liquid crystal compound, etc. The physical property value was measured by the method described later. Many of these measurement methods are the methods described in the Standard of Electric Industries Association of Japan EIAJ / ED-2521A or a modified method thereof. Moreover, TFT was not attached to the TN element used for the measurement.

  Among the measured values, when the liquid crystal compound itself was used as a sample, the obtained value was described as experimental data. When a mixture of a liquid crystal compound and mother liquid crystals was used as a sample, values obtained by extrapolation were described as experimental data.

1-4-1) Phase structure and phase transition temperature (° C.):
Measurement was carried out by the methods (1) and (2) below.
(1) A compound is placed on a hot plate (Mettler FP-52 type hot stage) equipped with a polarizing microscope, and the phase state and its change are observed with a polarizing microscope while heating at a rate of 3 ° C./min. , Identified the type of liquid crystal phase.
(2) Using a scanning calorimeter DSC-7 system or Diamond DSC system manufactured by PerkinElmer Inc., the temperature is raised and lowered at a rate of 3 ° C./min, and the start point of the endothermic peak or exothermic peak accompanying the phase change of the sample The phase transition temperature was determined by onset.

Hereinafter, the crystal is expressed as K, and when the crystal can be distinguished, it is expressed as K ₁ or K ₂ , respectively. Further, the smectic phase is represented as Sm, the nematic phase is represented as N, and the chiral nematic phase is represented as N ^* . The liquid (isotropic) was designated as I. When the smectic phase can be distinguished from the smectic B phase or the smectic A phase, it is expressed as SmB or SmA, respectively. BP represents a blue phase or an optically isotropic liquid crystal phase. The coexistence state of two phases may be expressed in the form of (N ^* + I) and (N ^* + BP). Specifically, (N ^* + I) represents a phase in which a non-liquid crystal isotropic phase and a chiral nematic phase coexist, and (N ^* + BP) represents a BP phase or an optically isotropic liquid crystal phase. Represents a phase in which a chiral nematic phase coexists. Un represents an unidentified phase that is not optically isotropic. As a notation of the phase transition temperature, for example, “K 50.0 N 100.0 I” means that the phase transition temperature (KN) from the crystal to the nematic phase is 50.0 ° C., and the phase from the nematic phase to the liquid The transition temperature (NI) is 100.0 ° C. The same applies to other notations.

1-5) Maximum temperature of nematic phase (T _NI ; ° C.)
Place a sample (mixture of liquid crystal compound and mother liquid crystal) on a hot plate (Mettler FP-52 hot stage) of a melting point measurement apparatus equipped with a polarizing microscope, and heat the polarizing microscope while heating at a rate of 1 ° C./min. Observed. The temperature at which a part of the sample changed from a nematic phase to an isotropic liquid was defined as the upper limit temperature of the nematic phase. Hereinafter, the upper limit temperature of the nematic phase may be simply abbreviated as “upper limit temperature”.

1-6) Low temperature compatibility The mother liquid crystal and the liquid crystal compound are mixed so that the liquid crystal compound is in an amount of 20% by weight, 15% by weight, 10% by weight, 5% by weight, 3% by weight, and 1% by weight. The prepared sample is prepared, and the sample is put in a glass bottle. The glass bottle was stored in a freezer at −10 ° C. or −20 ° C. for a certain period, and then it was observed whether a crystal or smectic phase was precipitated.

1-7) Viscosity (bulk viscosity; η; measured at 20 ° C .; mPa · s)
A mixture of the liquid crystal compound and the mother liquid crystal was measured using an E-type viscometer.

1-8) Refractive index anisotropy (Δn)
The measurement was performed at 25 ° C. using an Abbe refractometer using light having a wavelength of 589 nm and a polarizing plate attached to the eyepiece. After rubbing the surface of the main prism in one direction, a sample (mixture of liquid crystal compound and mother liquid crystal) was dropped onto the main prism. The refractive index (n‖) was measured when the direction of polarized light was parallel to the direction of rubbing. The refractive index (n⊥) was measured when the direction of polarized light was perpendicular to the direction of rubbing. The value of refractive index anisotropy (Δn) was calculated from the equation: Δn = n∥−n⊥.

1-9) Dielectric anisotropy (Δε; measured at 25 ° C.)
A sample (mixture of a liquid crystal compound and a mother liquid crystal) was put in a liquid crystal cell in which the distance (gap) between the two glass substrates was about 9 μm and the twist angle was 80 degrees. 20 volts was applied to the cell, and the dielectric constant (ε 率) in the major axis direction of the liquid crystal molecules was measured. 0.5 V was applied, and the dielectric constant (ε⊥) in the minor axis direction of the liquid crystal molecules was measured. The value of dielectric anisotropy was calculated from the equation: Δε = ε∥−ε⊥.

1-10) Pitch (P; measured at 25 ° C .; nm)
The pitch length was measured using selective reflection (Liquid Crystal Manual 196 pages 2000, Maruzen). For the selective reflection wavelength λ, the relational expression <n> p / λ = 1 holds. Here, <n> represents an average refractive index and is given by the following equation. <n> = {(n _{|| ^{2 + n ⊥ 2) / 2}} } 1/2. The selective reflection wavelength was measured with a microspectrophotometer (JEOL Ltd., trade name MSV-350). The pitch was obtained by dividing the obtained reflection wavelength by the average refractive index. The pitch of cholesteric liquid crystals having a reflection wavelength in the longer wavelength region than visible light is proportional to the reciprocal of the concentration of the optically active compound in the region where the optically active compound concentration is low. The length was measured at several points and determined by a linear extrapolation method. The “optically active compound” corresponds to the chiral agent in the present invention.

  In the present invention, the characteristic value of the liquid crystal composition can be measured according to the following method. Many of them are the method described in the Standard of Electric Industries Association of Japan EIAJ ED-2521A or a modified method thereof. No TFT was attached to the TN device used for measurement.

1-11) Maximum temperature of nematic phase (NI; ° C.)
A sample was placed on a hot plate of a melting point measurement apparatus equipped with a polarizing microscope and heated at a rate of 1 ° C./min. The temperature was measured when a part of the sample changed from a nematic phase to an isotropic liquid. The upper limit temperature of the nematic phase may be abbreviated as “upper limit temperature”.

1-12) of a nematic phase lower limit temperature (T _C; ° C.)
A sample having a nematic phase was stored in a freezer at 0 ° C., −10 ° C., −20 ° C., −30 ° C., and −40 ° C. for 10 days, and then the liquid crystal phase was observed. For example, when the sample remains in a nematic phase at −20 ° C. and changes to a crystal (or smectic phase) at −30 ° C., T _C is described as ≦ −20 ° C. The lower limit temperature of the nematic phase may be abbreviated as “lower limit temperature”.

1-13) Transition temperature of optically isotropic liquid crystal phase Place the sample on the hot plate of the melting point measurement apparatus equipped with a polarizing microscope, and in the crossed Nicol state, first the temperature until the sample becomes the non-liquid crystal isotropic phase After raising the temperature, the temperature was lowered at a rate of 1 ° C./min, and a completely chiral nematic phase or an optically isotropic liquid crystal phase appeared. The temperature at which the phase transition in the temperature lowering process was measured, then the temperature was increased at a rate of 1 ° C./min, and the temperature at which the phase transition in the temperature rising process was measured. In the present invention, unless otherwise specified, the phase transition temperature in the temperature raising process is defined as the phase transition temperature. In the optically isotropic liquid crystal phase, when it was difficult to distinguish the phase transition temperature in the dark field under crossed Nicols, the phase transition temperature was measured by shifting the polarizing plate by 1 to 10 ° from the crossed Nicols state.

1-14) Viscosity (Rotational viscosity; γ1; measured at 25 ° C .; mPa · s)
(1) Sample with positive dielectric anisotropy: Measurement was performed according to the method described in M. Imai et al., Molecular Crystals and Liquid Crystals, Vol. 259, 37 (1995). A sample was put in a TN device having a twist angle of 0 ° and a distance (cell gap) between two glass substrates of 5 μm. The voltage was applied to the TN device stepwise in the range of 16 to 19.5 volts every 0.5 volts. After no application for 0.2 seconds, the application was repeated under the condition of only one rectangular wave (rectangular pulse; 0.2 seconds) and no application (2 seconds). The peak current and peak time of the transient current generated by this application were measured. The value of rotational viscosity was obtained from these measured values and the calculation formula (8) on page 40 of the paper by M. Imai et al. The value of dielectric anisotropy necessary for this calculation was obtained by the following dielectric anisotropy measurement method using the element used for the measurement of the rotational viscosity.

(2) Sample with negative dielectric anisotropy: Measurement was performed according to the method described in M. Imai et al., Molecular Crystals and Liquid Crystals, Vol. 259, 37 (1995). A sample was put in a VA device having a distance (cell gap) between two glass substrates of 20 μm. This element was applied stepwise in increments of 1 volt in the range of 30 to 50 volts. After no application for 0.2 seconds, the application was repeated under the condition of only one rectangular wave (rectangular pulse; 0.2 seconds) and no application (2 seconds). The peak current and peak time of the transient current generated by this application were measured. The value of rotational viscosity was obtained from these measured values and the paper by M. Imai et al., Formula (8) on page 40. As the dielectric anisotropy necessary for this calculation, a value measured by the following dielectric anisotropy was used.

1-15) Refractive index anisotropy (Δn; measured at 25 ° C.)
The measurement was performed with an Abbe refractometer using light having a wavelength of 589 nm and a polarizing plate attached to the eyepiece. After rubbing the surface of the main prism in one direction, the sample was dropped on the main prism. The refractive index (n‖) was measured when the direction of polarized light was parallel to the direction of rubbing. The refractive index (n⊥) was measured when the direction of polarized light was perpendicular to the direction of rubbing. The value of refractive index anisotropy was calculated from the equation: Δn = n∥−n⊥. When the sample was a composition, the refractive index anisotropy was measured by this method.

1-16) Dielectric anisotropy (Δε; measured at 25 ° C.):
(1) Composition having positive dielectric anisotropy: A sample was put in a liquid crystal cell in which the distance (gap) between two glass substrates was about 9 μm and the twist angle was 80 degrees. 20 volts was applied to the cell, and the dielectric constant (ε 率) in the major axis direction of the liquid crystal molecules was measured. 0.5 V was applied, and the dielectric constant (ε⊥) in the minor axis direction of the liquid crystal molecules was measured. The value of dielectric anisotropy was calculated from the equation: Δε = ε∥−ε⊥.

(2) Composition having a negative dielectric anisotropy: A sample was placed in a liquid crystal cell treated in homeotropic alignment, and a dielectric constant (ε‖) was measured by applying 0.5 volts. A sample was put in a liquid crystal cell treated to homogeneous alignment, and a dielectric constant (ε⊥) was measured by applying 0.5 volts. The value of dielectric anisotropy was calculated from the equation: Δε = ε∥−ε⊥.

1-17) Threshold voltage (Vth; measured at 25 ° C .; V)
1) A composition having a positive dielectric anisotropy: a normally white mode (normally white mode) in which a distance (gap) between two glass substrates is (0.5 / Δn) μm and a twist angle is 80 degrees. A sample was put in a liquid crystal display element in white mode). Δn is a value of refractive index anisotropy measured by the above method. A rectangular wave having a frequency of 32 Hz was applied to this element. The voltage of the rectangular wave was increased and the value of the voltage when the transmittance of light passing through the element reached 90% was measured.

2) Composition having a negative dielectric anisotropy: For a normally black mode liquid crystal display element in which the distance (gap) between two glass substrates is about 9 μm and is processed in a homeotropic alignment. A sample was placed. A rectangular wave having a frequency of 32 Hz was applied to this element. The voltage of the rectangular wave was raised, and the value of the voltage when the transmittance of light passing through the element reached 10% was measured.

1-18) Voltage holding ratio (VHR; measured at 25 ° C .;%)
The TN device used for the measurement has a polyimide alignment film, and the distance (cell gap) between the two glass substrates is 6 μm. This element was sealed with an adhesive polymerized by ultraviolet rays after putting a sample. The TN device was charged by applying a pulse voltage (60 microseconds at 5 V). The decaying voltage was measured for 16.7 milliseconds with a high-speed voltmeter, and the area A between the voltage curve and the horizontal axis in a unit cycle was determined. The area B is an area when it is not attenuated. The voltage holding ratio is a percentage of the area A with respect to the area B.

1-19) Spiral pitch (measured at 20 ° C .; μm)
Kano's wedge cell method was used to measure the helical pitch. A sample was injected into a Kano wedge-shaped cell, and the distance (a; unit: μm) between disclination lines observed from the cell was measured. The helical pitch (P) was calculated from the formula P = 2 · a · tan θ. θ is the angle between the two glass plates in the wedge-shaped cell.

Alternatively, the pitch length was measured using selective reflection (Liquid Crystal Manual 196, 2000, Maruzen). For the selective reflection wavelength λ, the relational expression <n> p / λ = 1 holds. Here, <n> represents an average refractive index and is given by the following equation. <n> = {(n ² + n ² ) / 2} ^1/2 . The selective reflection wavelength was measured with a microspectrophotometer (JEOL Ltd., trade name MSV-350). The pitch was obtained by dividing the obtained reflection wavelength by the average refractive index.
The pitch of a cholesteric liquid crystal having a reflection wavelength in the longer wavelength region than visible light is proportional to the reciprocal of the concentration of the chiral agent in a region where the chiral agent concentration is low, so the pitch length of a liquid crystal having a selective reflection wavelength in the visible light region is increased. Several points were measured and obtained by linear extrapolation.

  The ratio (percentage) of the component or the liquid crystal compound is a weight percentage (% by weight) based on the total weight of the liquid crystal compound. The composition is prepared by measuring the weight of components such as a liquid crystal compound and then mixing them. Therefore, it is easy to calculate the weight percentage of the component.

[Example 1]
Synthesis Examples and characteristics of the compounds represented by the formula (1-2) of the present application are described in Synthesis Examples 1 to 4 below.

式（１−２）において、Ｒ^１ａがＣ_４Ｈ_９、およびＸ^１ａが−ＣＦ_３である、上記式（１−２−Ｓ１）で表される化合物（化合物（１−２−Ｓ１））を以下のとおりに合成した。

[Synthesis Example 1] Synthesis of Compound (1-2-S1)

In the formula (1-2), a compound represented by the above formula (1-2-S1) wherein R ^1a is C ₄ H ₉ and X ^1a is —CF ₃ (compound (1-2-S1)) Was synthesized as follows.

(First Step) Synthesis of Compound (S107) Under a nitrogen atmosphere, a solution of compound (S106) (15.0 g, 38.2 mmol) in THF (150 mL) was cooled to −40 ° C., and an n-butyllithium / n-hexane solution was obtained. (1.57 mol / L, 29.0 mL) was added dropwise and stirred at the same temperature for 1 hour. Further, dry ice (2.01 g, 45.8 mmoL) was added little by little at the same temperature, and the mixture was stirred for 1 hour while gradually returning to room temperature. The reaction solution was poured into 2N-HCl water, and after confirming that the solution was acidic with litmus paper, it was extracted twice with diethyl ether (200 mL), washed three times with water, and then the organic phase was concentrated under reduced pressure. N-Heptane was added to the residue, and the mixture was heated and stirred at 40 ° C. for 5 minutes, then slowly cooled to −20 ° C., and the solid was filtered. The filter crystals were taken out and dried under reduced pressure to obtain a carboxylic acid derivative (S107) (15.8 g, 36.1 mmoL).

(Second Stage) Synthesis of Compound (1-2-S1) Under a nitrogen atmosphere, a solution of phenol derivative (S108) (2.72 g, 13.7 mmol) in dichloromethane (120 mL) was cooled to 0 ° C., and N, N′— Dichlorohexylcarbodiimide (2.96 g, 14.4 mmol), 4-dimethylaminopyridine (0.168 g, 1.37 mmol), and carboxylic acid derivative (S107) (6.00 g, 13.7 mmol) were added and stirred at room temperature for 8 hours. The reaction mixture was poured into water, dichloromethane (120 mL) was added, the mixture was washed twice with layered water and three times with water, and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (developing solvent: toluene / n-heptane = 1/2 (volume)) and further purified by recrystallization filtration (solvent: toluene / n-heptane = 1/4 (volume)). (1-2-S1) (4.14 g, 6.70 mmoL) was obtained. The melting point (° C.) of this compound was C 123.6 I.
¹ H-NMR (CDCl ₃ , ppm): δ 0.944-0.974 (3H, t), 1.36-1.43 (2H, m), 1.61-1.67 (2H, m), 2.65-2.68 (2H, t), 7.00- 7.04 (2H, dd), 7.02-7.05 (1H, dd), 7.07-7.09 (1H, dd), 7.12-7.14 (2H, d), 7.33-7.37 (2H, dd), 7.53 (1H, dd)
¹⁹ F-NMR (CDCl ₃ , ppm): δ -109.23- -109.25 (2F, d), -111.92- -111.94 (1F, d), -118.64- -118.68 (1F, dd), -132.74- 132.81 ( 2F, dd), -163.07- -163.08 (1F, tt)
Next, the four compounds described as the mother liquid crystal A described above were mixed to prepare a mother liquid crystal A having a nematic phase. The physical properties of the mother liquid crystal A were as follows.
Maximum temperature (T _NI ) = 71.7 ° C .; dielectric anisotropy (Δε) = 11.0; refractive index anisotropy (Δn) = 0.137.

A liquid crystal composition AS1 composed of the base liquid crystal A (95% by weight) and the compound (1-2-S1) (5% by weight) obtained in Synthesis Example 1 was prepared. The physical property value of the obtained liquid crystal composition AS1 was measured, and the extrapolated value of the physical property of the compound (1-2-S1) was calculated by extrapolating the measured value. The values were as follows:
Maximum temperature (T _NI ) = 55 ° C .; dielectric anisotropy (Δε) = 75.4; refractive index anisotropy (Δn) = 0.170.
From these results, it was found that the compound (1-2-S1) was a compound having a large refractive index anisotropy (Δn) and a dielectric anisotropy (Δε).

式（１−２）において、Ｒ^１ａがＣ_４Ｈ_９、およびＸ^１ａが−Ｆである、上記式（１−２−Ｓ２）で表される化合物（化合物（１−２−Ｓ２））を合成例１の方法に準じて合成した。相転移点（℃）は、Ｃ １１８．１（Ｎ １０４．７） Ｉであった。 [Synthesis Example 2] Synthesis of Compound (1-2-S2)

In the formula (1-2), a compound represented by the above formula (1-2-S2) (compound (1-2-S2)) in which R ^1a is C ₄ H ₉ and X ^1a is —F. Synthesis was performed according to the method of Synthesis Example 1. The phase transition point (° C.) was C 118.1 (N 104.7) I.

A liquid crystal composition AS1 composed of the base liquid crystal A (95% by weight) and the compound (1-2-S2) (5% by weight) obtained in Synthesis Example 2 was prepared. The physical property value of the obtained liquid crystal composition AS1 was measured, and the extrapolated value of the physical property of the compound (1-2-S2) was calculated by extrapolating the measured value. The values were as follows:
Maximum temperature (T _NI ) = 49.7 ° C .; dielectric anisotropy (Δε) = 63.9; refractive index anisotropy (Δn) = 0.177.
From these results, it was found that the compound (1-2-S2) was a compound having a large refractive index anisotropy (Δn) and a dielectric anisotropy (Δε).

式（１−２）において、Ｒ^１ａがＣ_５Ｈ_１１、およびＸ^１ａが−ＣＦ_３である、上記式（１−２−Ｓ３）で表される化合物（化合物（１−２−Ｓ３））を合成例１の方法に準じて合成した。相転移点（℃）は、Ｃ １１４．９ Ｉであった。 [Synthesis Example 3] Synthesis of Compound (1-2-S3)

In the formula (1-2), a compound represented by the above formula (1-2-S3), wherein R ^1a is C ₅ H ₁₁ and X ^1a is —CF ₃ (compound (1-2-S3)). Was synthesized according to the method of Synthesis Example 1. The phase transition point (° C.) was C 114.9 I.

A liquid crystal composition AS1 composed of the base liquid crystal A (95% by weight) and the compound (1-2-S3) (5% by weight) obtained in Synthesis Example 3 was prepared. The physical property value of the obtained liquid crystal composition AS1 was measured, and the extrapolated value of the physical property of the compound (1-2-S3) was calculated by extrapolating the measured value. The values were as follows:
Maximum temperature (T _NI ) = 55.7 ° C .; dielectric anisotropy (Δε) = 78.1; refractive index anisotropy (Δn) = 0.177.
From these results, it was found that the compound (1-2-S3) was a compound having a large refractive index anisotropy (Δn) and a dielectric anisotropy (Δε).

式（１−２）において、Ｒ^１ａがＣ_６Ｈ_１３−、およびＸ^１ａが−ＣＦ_３である、上記式（１−２−Ｓ４）で表される化合物（化合物（１−２−Ｓ４））を合成例１の方法に準じて合成した。相転移点（℃）は、Ｃ １１７．８ Ｉであった。 [Synthesis Example 4] Synthesis of Compound (1-2-S4)

In the formula (1-2), a compound represented by the above formula (1-2-S4) wherein R ^1a is C ₆ H ₁₃ — and X ^1a is —CF ₃ (compound (1-2-S4)) ) Was synthesized according to the method of Synthesis Example 1. The phase transition point (° C.) was C 117.8 I.

A liquid crystal composition AS1 composed of the base liquid crystal A (95% by weight) and the compound (1-2-S4) (5% by weight) obtained in Synthesis Example 3 was prepared. The physical property value of the obtained liquid crystal composition AS1 was measured, and the extrapolated value of the physical property of the compound (1-2-S4) was calculated by extrapolating the measured value. The values were as follows:
Maximum temperature (T _NI ) = 53.7 ° C .; dielectric anisotropy (Δε) = 73.9; refractive index anisotropy (Δn) = 0.157.
From these results, it was found that the compound (1-2-S4) is a compound having a large refractive index anisotropy (Δn) and a dielectric anisotropy (Δε).

表１の続き

表１の続き

表１の続き

[Example 2] Preparation of nematic liquid crystal composition (NLC) As shown in Table 1, nematic liquid crystal composition NLC containing compounds (1-2-S1) to (1-2-S4) synthesized in Example 1 was used. -A, NLC-B, NLC-C, NLC-D, NLC-E and NLC-F were prepared. In addition, NLC-R was prepared as a reference for NLC-A and NLC-B.

Continuation of Table 1

Continuation of Table 1

Continuation of Table 1

Table 2 shows the phase transition point of each nematic liquid crystal composition.

[Example 3] Preparation of chiral liquid crystal composition (CLC) Next, each nematic liquid crystal composition shown in Table 1 was mixed with chiral agents BN-H4, BN-H5 and CD1 shown below to obtain a chiral liquid crystal composition. The products CLC-A, CLC-B, CLC-C, CLC-D, CLC-E, CLC-F and CLC-R were prepared. The composition of the chiral liquid crystal composition was as follows, and the phase transition points were as shown in Table 3.
CLC-A
NLC-A 94.7% by weight
BN-H4 2.65% by weight
BN-H5 2.65% by weight
CLC-B
NLC-B 94.7% by weight
BN-H4 2.65% by weight
BN-H5 2.65% by weight
CLC-C
NLC-C 95.2 wt%
CD1 4.8% by weight
CLC-D
NLC-C 95.5 wt%
CD1 4.5% by weight
CLC-E
NLC-C 95.5 wt%
CD1 4.5% by weight
CLC-F
NLC-C 95.5 wt%
CD1 4.5% by weight
CLC-R
NLC-C 95.2 wt%
BN-H4 2.65% by weight
BN-H5 2.65% by weight

ＢＮ−Ｈ５

ＣＤ１

BN-H4

BN-H5

CD1

[Example 4] Preparation of liquid crystal composition (MLC) as a mixture with a polymerizable monomer Each chiral liquid crystal composition (CLC) prepared in Example 3 was heated and mixed in a isotropic phase with a mixture of a polymerizable monomer. As a result, liquid crystal compositions MLC-A, MLC-B, MLC-C, MLC-D, MLC-E, MLC-F and MLC-R were prepared. The compositions of these liquid crystal compositions are shown below, and the phase transition temperatures are shown in Table 4.
MLC-A
CLC-A 88.8% by weight
n-Hexadecyl acrylate 6.0% by weight
LCA-12 4.8% by weight
DMPA 0.4 wt%
MLC-B
CLC-B 88.8 wt%
n-Hexadecyl acrylate 6.0% by weight
LCA-12 4.8% by weight
DMPA 0.4 wt%
MLC-C
CLC-C 88.8% by weight
n-Hexadecyl acrylate 6.0% by weight
LCA-12 4.8% by weight
DMPA 0.4 wt%
MLC-D
CLC-D 88.8 wt%
n-Hexadecyl acrylate 6.0% by weight
LCA-12 4.8% by weight
DMPA 0.4 wt%
MLC-E
CLC-E 88.2% by weight
n-Hexadecyl acrylate 6.0% by weight
LCA-12 4.8% by weight
DMPA 0.8 wt%
MLC-F
CLC-F 88.8 wt%
n-Hexadecyl acrylate 6.0% by weight
LCTA-6 4.8% by weight
DMPA 0.4 wt%
MLC-R
CLC-R 88.8 wt%
n-Hexadecyl acrylate 6.0% by weight
LCA-12 4.8% by weight
DMPA 0.4 wt%

  The above LCA-6, LCA-12 and DMPA are respectively 1,4-di (4- (6- (acryloyloxy) hexyloxy) benzoyloxy) -2-methylbenzene (LCA-6), 1,4- Di (4- (6- (acryloyloxy) dodecyloxy) benzoyloxy) -2-methylbenzene (LCA-12), 2,2′-dimethoxyphenylacetophenone, DMPA is a photopolymerization initiator. LCTA-6 showed the chemical structure below.

ＬＣＡ−１２

ＬＣＴＡ−６

LCA-6

LCA-12

LCTA-6

[Example 5] Cell in which preparation of polymer / liquid crystal composite material is held The liquid crystal composition (MLC), which is a mixture of a chiral liquid crystal composition (CLC) and a polymerizable monomer, is not subjected to alignment treatment. It was sandwiched between a comb-shaped electrode substrate and a counter glass substrate (non-electrode provided) and heated to a blue phase. In this state, ultraviolet light (ultraviolet light intensity: 23 mWcm-2 (365 nm)) is irradiated for 1 minute to conduct a polymerization reaction, and polymer / liquid crystal composite materials PSBP-A, PSBP-B, PSBP-C, PSBP-D. , PSBP-E, PSBP-F and PSBP-R were sandwiched (cell thickness 7-9 μm). The polymerization temperature was as shown in Table 5.

  The polymer / liquid crystal composite material (PSBP) thus obtained maintained an optically isotropic liquid crystal phase even when cooled to room temperature.

Example 6 Optical System Using Cell The cell sandwiched with the polymer / liquid crystal composite material obtained in Example 5 was set in the optical system shown in FIG. Specifically, a white light source of a polarization microscope (Nikon Eclipse LV100POL) is used as the light source, the incident angle to the cell is perpendicular to the cell surface, and the line direction of the comb-shaped electrode is Polarizer and Analyzer polarizer A cell in which the polymer / liquid crystal composite material obtained in Example 5 was held so as to be 45 ° with respect to each other was set (FIG. 2).
Using this optical system, the relationship between the applied voltage and the transmittance of the polymer / liquid crystal composite material obtained in Example 5 at room temperature was examined. Table 5 shows the physical property values of the polymer / liquid crystal composite material (PSBP) sandwiched between the cells. Note that the response time data are those when applying and removing the saturation voltage.

CLC-A and CLC-B are compositions obtained by adding the compound of formula (1) to CLC-R.
PSBP-A had a saturation voltage (Vmax) of 40.4 V and a contrast ratio of 968.4. The drive voltage was lowered and the contrast was improved as compared with PSBP-R serving as a reference. PSBP-B has a saturation voltage (Vmax) of 45.2 V and a contrast ratio of 1211. The drive voltage is equivalent to that of PSBP-R serving as a reference, but the contrast is remarkably improved. It was found that the compound of the formula (1) is an effective compound for lowering the driving voltage and improving the contrast.

  As is clear from the above examples and comparative examples, the optical element of the present invention is superior to the prior art because of low driving voltage or high contrast.

  Examples of the utilization method of the present invention include an optical element such as a display element using a polymer / liquid crystal composite.

1 Electrode 2 Electrode 3 Light source 4 Polarizer (Polarizer)
5 Comb electrode cell 6 Analyzer (polarizer) (Analyzer)
7 Photodetector

Claims (18)

A liquid crystal composition containing an achiral component T containing at least one compound 1 represented by the formula (1) and a chiral agent and exhibiting an optically isotropic liquid crystal phase.

In the formula (1), R ¹ is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is —O—, —S—, —COO—, —OCO—, —CH═CH—, —CF═CF—, or —C≡C— may be substituted, and —CH ₂ — in the alkyl and the alkyl may be —O—, —S—, —COO—, — At least one hydrogen in the group replaced by OCO-, -CH = CH-, -CF = CF- or -C≡C- may be replaced by halogen or alkyl having 1 to 3 carbon atoms;
L ¹¹ , L ¹² , L ¹³ , L ¹⁴ , L ¹⁵ , L ¹⁶ and L ¹⁷ are each independently hydrogen or fluorine;
X ¹ is halogen, —CF ₃ , —OCF ₃ , —C≡N, or —N═C═S;
n11 is 0 or 1.   The liquid crystal composition according to claim 1, wherein n11 is 0 in the formula (1). The liquid crystal composition according to claim 1, wherein in formula (1), L ¹¹ is hydrogen, and L ¹² , L ¹³ , L ¹⁶ and L ¹⁷ are fluorine. The liquid crystal composition according to claim 1, wherein the compound represented by formula (1) is a compound represented by formula (1-1) or (1-2).

In the above formula, R ^1a is alkyl having 1 to 10 carbons;
X ^1a is fluorine, chlorine, —C≡N, —CF ₃ or —OCF ₃ . The liquid crystal according to any one of claims 1 to 4, further comprising at least one compound selected from the group consisting of the compound 3 represented by the following formula (3) and the compound 7 represented by the formula (7). Composition.

In the formula (3), R ³ is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, and at least one in the alkyl Hydrogen may be replaced by fluorine or chlorine provided that -O- and -CH = CH- and -CO- and -CH = CH- are not adjacent in the alkyl;
Z ³¹ , Z ³² and Z ³³ are each independently a single bond or alkylene having 1 to 4 carbon atoms, and at least one —CH ₂ — in the alkylene is —O—, —COO— or —CF May be replaced by ₂ O-;
L ³¹ , L ³² , L ³³ , L ³⁴ and L ³⁵ are each independently hydrogen or fluorine;
X ³ is hydrogen, halogen, —SF ₅ or alkyl having 1 to 10 carbons, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, and at least one in the alkyl Hydrogen may be replaced by fluorine or chlorine, provided that —O— and —CH═CH— are not adjacent to each other in the alkyl, and —CO— and —CH═CH— are not adjacent to each other. .

In the formula (7), R ⁷ is alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, wherein at least one hydrogen in the alkyl is May be replaced by fluorine or chlorine provided that -O- and -CH = CH- and -CO- and -CH = CH- are not adjacent in the alkyl;
L ⁷¹ , L ⁷² , L ⁷³ , L ⁷⁴ , L ⁷⁵ , L ⁷⁶ , L ⁷⁷ and L ⁷⁸ are each independently hydrogen or fluorine;
Z ^71, Z ⁷² and Z ⁷³ are each independently a single bond, —COO— or —CF ₂ O—, but at least one is —COO— or —CF ₂ O—;
n71 and n72 are each independently 0 or 1, and n71 ≧ n72;
X ⁷ is hydrogen, halogen, —SF ₅ or alkyl having 1 to 10 carbons, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, and at least one in the alkyl Hydrogen may be replaced by fluorine or chlorine, provided that —O— and —CH═CH— are not adjacent to each other in the alkyl, and —CO— and —CH═CH— are not adjacent to each other. . The liquid crystal composition according to claim 5, wherein the compound 3 is one or more selected from the group of compounds represented by formula (3-2) and formula (3-3).

In the above formula, each R ^3A independently represents an alkyl having 1 to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl having 2 to 12 carbons or at least one hydrogen in which at least one hydrogen may be replaced by fluorine. 2 to 12 alkenyl;
L ³¹ , L ³² , L ³³ , L ³⁴ and L ³⁵ are each independently hydrogen or fluorine;
X ^3A is fluorine, chlorine, —CF ₃ or —OCF ₃ . The liquid crystal composition according to claim 5, wherein the compound 7 is one or more selected from the group of compounds represented by formulas (7-1) to (7-8).

In the above formula, R ^7A is hydrogen, alkyl having 1 to 12 carbons, alkoxy having 1 to 11 carbons, alkenyl having 2 to 12 carbons, or 2 to 12 carbons in which at least one hydrogen is replaced by fluorine. Is alkenyl;
L ⁷² , L ⁷⁴ , L ⁷⁵ , L ⁷⁶ , L ⁷⁷ and L ⁷⁸ are each independently hydrogen or fluorine;
In formulas (7-1) to (7-3) and (7-6) to (7-8), Z ⁷¹ and Z ⁷² are each independently a single bond, —COO— or —CF ₂ O—. And at least one is —COO— or —CF ₂ O—, and in formulas (7-4) and (7-5), Z ⁷¹ independently represents —COO— or —CF ₂ O. −
X ^7A is fluorine, chlorine, —CF ₃ or —OCF ₃ . Compound 7 has the formulas (7-2-2-E), (7-2-5-E), (7-2-2-F), (7-2-5-F) and (7-2-5). The liquid crystal composition according to claim 7, which is one or more selected from the group of compounds represented by 6-F).

(In the above formula, R ^7A is an alkyl having 1 to 12 carbons, an alkoxy having 1 to 11 carbons, an alkenyl having 2 to 12 carbons, or a carbon having 2 to 12 carbons in which at least one hydrogen is replaced with fluorine. Is alkenyl;
X ^7A is fluorine, chlorine, —CF ₃ or —OCF ₃ . )   3% to 20% by weight of Compound 1 in total with respect to the total weight of the achiral component T, 20% to 67% by weight of Compound 3, and 30% to 77% by weight of Compound 7 in total The liquid crystal composition according to claim 5, which is contained. The achiral component T further includes at least one compound selected from the group of compound 4 represented by formula (4) and compound 2 represented by (2). The liquid crystal composition described in 1.

In the formula (4), R ⁴ is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or 2 to 12 carbons in which at least one hydrogen is replaced with fluorine. Alkenyl of
Each ring B is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 3,5-difluoro-1, 4-phenylene, 3,5-dichloro-1,4-phenylene or pyrimidine-2,5-diyl;
Each Z ⁴¹ is independently a single bond, ethylene, —COO—, —OCO—, —CF ₂ O— or —OCF ₂ —;
L ⁴⁸ and L ⁴⁹ are each independently hydrogen or fluorine;
X ⁴ is fluorine, chlorine, —CF ₃ or —OCF ₃ ;
n41 is 1, 2, 3 or 4, provided that when n41 is 3 or 4, at least one Z ⁴¹ is —CF ₂ O— or —OCF ₂ —, and when n41 is 3, Not all of B is 1,4-phenylene substituted with fluorine.

In the formula (2), R ² is hydrogen or alkyl having 1 to 20 carbon atoms, and at least one —CH ₂ — in the alkyl is replaced by —O—, —S—, —COO— or —OCO—. And at least one —CH ₂ —CH ₂ — in the alkyl may be replaced by —CH═CH—, —CF═CF— or —C≡C—, In a group in which at least one —CH ₂ — is replaced by —O—, —S—, —COO— or —OCO—, or at least one —CH ₂ — in alkyl is —O—, —S—, At least one hydrogen in the group in which at least one —CH ₂ —CH ₂ — in the group replaced with —COO— or —OCO— is replaced with —CH═CH— or —C≡C— is fluorine or Replace with chlorine May be, however, -O- and -CH = CH- and -CO- and -CH = CH- not be adjacent in ^{R 2;}
Ring A ²¹ , Ring A ²² , Ring A ²³ , Ring A ²⁴ and Ring A ²⁵ are each independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene. 1,4-phenylene in which one or two hydrogens are replaced with fluorine, 1,4-phenylene in which two hydrogens are replaced with fluorine and chlorine, respectively, pyridine-2,5-diyl, pyrimidine-2,5 -Diyl;
Z ²¹ , Z ²² , Z ²³ , Z ²⁴ , Z ²⁵ and Z ²⁶ are each independently a single bond or alkylene having 1 to 4 carbon atoms, and at least one —CH ₂ — in the alkylene is — O -, - COO- or may be replaced by _-CF 2 O-;
L ²¹ , L ²² and L ²³ are each independently hydrogen or fluorine;
X ² is fluorine, chlorine, —CF ₃ , —CHF ₂ , —CH ₂ F , —OCF ₃ , —OCHF ₂ , —OCH ₂ F, —OCF ₂ CFHCF ₃ or —CH═CHCF ₃ ;
n21, n22, n23, n24 and n25 are each independently 0 or 1, and 2 ≦ n21 + n22 + n23 + n24 + n25 ≦ 3. The achiral component T is one or more compounds 4 selected from the group of compounds represented by formulas (4-1) to (4-9), and formulas (2-1-1-2), (2-1 2-1), (2-1-3-1), (2-1-3-2), (2-1-4-2) and (2-1-4-3) The liquid crystal composition according to claim 1 , further comprising one or more compounds 2 selected from the group consisting of:

(In the above formula, each R ^4A independently represents an alkyl having 1 to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl having 2 to 12 carbons or at least one hydrogen in which at least one hydrogen is replaced by fluorine. -12 alkenyl;
X ^4A is fluorine, chlorine, —CF ₃ or —OCF ₃ ;
L ^{40 to} L ⁴⁹ are each independently hydrogen or fluorine.

In the above formula, R ^2A is alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons, or alkenyl having 2 to 12 carbons in which at least one hydrogen is replaced by fluorine. Is;
(F) is each independently hydrogen or fluorine;
X ^2A is fluorine, chlorine, —CF ₃ or —OCF ₃ . The liquid crystal composition according to any one of claims 1 to 11, wherein the chiral agent is at least one compound selected from the group of compounds represented by formulas (K1) to (K6).

(In the formula, ^{R K} is independently hydrogen, halogen, -C≡N, alkyl of -N = C = O, -N = C = S or a C 1-20, in the alkyl At least one —CH ₂ — may be replaced by —O—, —S—, —COO— or —OCO—, and at least one —CH ₂ —CH ₂ — in the alkyl is —CH═CH—. , -CF = CF- or -C≡C-, and at least one hydrogen in the alkyl may be replaced by fluorine or chlorine;
Each A is independently an aromatic 6-8 membered ring, a non-aromatic 3-8 membered ring, or a condensed ring having 9 or more carbon atoms, and at least one hydrogen of these rings is a halogen atom , C 1 -C 3 alkyl or haloalkyl may be substituted, ring —CH ₂ — may be substituted with —O—, —S— or —NH—, and —CH═ is —N═. May be replaced;
Each B is independently hydrogen, halogen, alkyl having 1 to 3 carbon atoms, haloalkyl having 1 to 3 carbon atoms, aromatic 6 to 8 membered ring, non-aromatic 3 to 8 membered ring, or A condensed ring having 9 or more carbon atoms, and at least one hydrogen of these rings may be replaced by halogen, alkyl having 1 to 3 carbon atoms or haloalkyl, and —CH ₂ — in the alkyl is —O—, -S- or -NH- may be substituted and -CH = may be replaced by -N =;
Z is each independently a single bond or alkylene having 1 to 8 carbon atoms, and at least one —CH ₂ — in the alkylene is —O—, —S—, —COO—, —OCO—, — CSO—, —OCS—, —N═N—, —CH═N— or —N═CH— may be substituted, and at least one —CH ₂ —CH ₂ — in the alkylene is —CH═CH. -, -CF = CF- or -C≡C- may be substituted, and at least one hydrogen in the alkylene may be replaced by halogen;
Each X is independently a single bond, —COO—, —OCO—, —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, or —CH ₂ CH ₂ —;
mK is each independently an integer of 1 to 4. )   The liquid crystal composition according to any one of claims 1 to 12, which exhibits a chiral nematic phase at any temperature of -20 ° C to 70 ° C, and has a helical pitch of 700 nm or less in at least a part of this temperature range. .   A mixture comprising the liquid crystal composition according to claim 1 and a polymerizable monomer.   A polymer / liquid crystal composite material obtained by polymerizing the mixture according to claim 14 and used for an element driven in an optically isotropic liquid crystal phase.   An optical element comprising an electrode disposed on one or both substrates, a liquid crystal medium disposed between the substrates, and an electric field applying means for applying an electric field to the liquid crystal medium via the electrodes, wherein the liquid crystal medium is claimed in claim The optical element which is a liquid crystal composition as described in any one of 1-13, or the polymer / liquid crystal composite material of Claim 15.   Use of the liquid crystal composition according to any one of claims 1 to 13 or the polymer / liquid crystal composite material according to claim 15 for an optical element. A compound represented by formula (1-1) or formula (1-2).

In the above formula, R ^1a is alkyl having 1 to 10 carbons;
X ^1a is fluorine, chlorine, —C≡N, —CF ₃ or —OCF ₃ .

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