JP2017039814A - Dichroic dye, liquid crystal composition, and liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new azo-based dichroic dye having a high order parameter (S value) and an absorption maximum wavelength in a long wavelength region, and a liquid crystal composition and a liquid crystal element containing the dye.SOLUTION: (1) The dichroic dye is represented by formula (I) below. In formula (I), Arand Arrepresent an aromatic ring; Xand Xrepresent an oxygen atom or -NR-; Rand Rrepresent an alkyl group or the like; Land Lrepresent a direct bond or a divalent connecting group; Ato Arepresent a 1,4-phenylene group or (E)-cyclohexane-1,4-diyl group which may have a substituent; Band Brepresent a connecting group having 4 or more atoms in a connected serial moiety; nto nrepresent an integer of 1 or more; mand mrepresent 0 or 1; and mrepresents an integer of 0 or more.SELECTED DRAWING: None

Description

  The present invention relates to a novel dichroic dye used for liquid crystal display and the like, a liquid crystal composition containing the dye, and a liquid crystal element.

  Many types of liquid crystal display elements have been proposed. For example, a guest-host type liquid crystal element is a cell in which a liquid crystal composition in which a dichroic dye is dissolved in a liquid crystal is sealed in a cell, and an electric field is applied to the cell. It is a liquid crystal element of a system that displays by changing the orientation of the cell and changing the light absorption state of the cell. This guest-host system is expected as a reflective liquid crystal element that uses a backlight and consumes less power.

Here, the dichroic dye constituting the liquid crystal composition together with the liquid crystal has an appropriate light absorption characteristic, a high dichroic order parameter value (hereinafter sometimes referred to as S value), a high solubility in the host liquid crystal, and Properties such as durability are required.
Anthraquinone dyes and azo dyes are known as dichroic dyes used in liquid crystal elements. In general, anthraquinone-based dyes are capable of obtaining various colors from yellow to cyan depending on their molecular structure, and are said to have excellent light resistance, but have the disadvantage of a small extinction coefficient and sharp absorption spectrum. There is. In contrast, azo dyes generally have a high dichroic ratio and a large extinction coefficient. Furthermore, since the absorption spectrum is broad, the number of dyes to be mixed can be reduced compared to anthraquinone dyes in applications where a desired black liquid crystal composition is formed by mixing with other dichroic dyes, In addition, there is an advantage that high contrast can be achieved even if the addition amount is small.

  Patent Documents 1 and 2 disclose azo dichroic dyes having a maximum absorption wavelength in the range of 390 nm to 600 nm. As azo dyes, the dichroic dye group having the highest order parameter (S value) and the dichroic dye group are disclosed. A liquid crystal composition containing a dye and a liquid crystal element excellent in contrast are described.

JP 2009-007485 JP JP 2009-007486 JP

Although the dichroic dye described in Patent Document 1 has a very good S value, as a further improvement, the solubility is further increased, the risk of precipitation from the host liquid crystal due to environmental changes is reduced, and the display capability due to an increase in viscosity There is a demand for a material that has a low decrease in the number.
An object of the present invention is to provide a novel azo-based dichroic dye having solubility that can withstand practical use while maintaining an order parameter (S value) with a high dichroic ratio. Another object of the present invention is to provide a guest-host type liquid crystal composition and a liquid crystal element including the same, which can realize display with high contrast by using a novel azo dichroic dye. .

As a result of intensive studies to solve the above problems, the present inventors have found that the mobility between the 6-membered ring structure and the 6-membered ring structure at the end of the azo dichroic dye represented by the following structural formula (I) is as follows. It was found that a dichroic dye having an order parameter (S value) with a high dichroic ratio can be realized by introducing a linear structure having a large. The present invention has been accomplished based on these findings.
That is, the gist of the present invention is as follows.
(1) A dichroic dye represented by the following formula (I).

[In the formula (I),
Ar ¹ and Ar ² each independently represent an aromatic ring which may have a substituent,
X ¹ and X ² each independently represent an oxygen atom or —NR ⁵ — (R ⁵ is a hydrogen atom or an alkyl group which may have a substituent);
R ¹ and R ² each independently represents a hydrogen atom or an optionally substituted alkyl group, alkenyl group, alkynyl group, or alkoxy group,
L ¹ and L ² represent a direct bond or a divalent linking group,
A ^{1 to} A ⁴ each independently represents a 1,4-phenylene group or (E) -cyclohexane-1,4-diyl group which may have a substituent,
B ¹ and B ² each represent a linking group having 4 or more atoms connected in series,
n ^{1 to} n ⁵ are integers of 1 or more, and when n ^{1 to} n ⁵ are integers of 2 or more, A ¹ , A ³ , A ⁴ , Ar ¹ and Ar ² present in one molecule are May be the same or different,
m ¹ and m ³ are 0 or 1, and m ² is an integer of 0 or more. ]
(2) The dichroic dye of (1), wherein m ¹ = m ² = m ³ = 1, n ² = 1, and L ¹ and L ² are a divalent linking group containing no cyclic structure and an azo bond .
(3) m ¹ = m ² = m ³ = 0, L ¹ is a group in which A ¹ and Ar ¹ are directly bonded or connected, and the series part to be connected is 2 atoms, L ² is a cyclic structure and an azo bond The dichroic dye of (1), which is a divalent linking group containing no
(4) The B ¹ and B ^{2 each} having an alkylene group, an alkenylene group, an alkynylene group, an ester group, an ether group or a carbonyl group, Color pigment.
(5) The dichroic dye as described in any one of (1) to (4) above, wherein the number of atoms in the series part of B ² represented by the formula (I) is an even number.
(6) The dichroic dye according to any one of (1) to (5), which has any one of the following formulas (II) and (III) as a partial structure.

[In the formula (II),
X ⁴ represents an oxygen atom or —NR ¹⁰ — (R ¹⁰ is a hydrogen atom or a monovalent substituent);
R ⁸ represents a hydrogen atom or an alkyl group which may have a substituent,
B ⁴ represents a divalent linking group having 4 or more atoms in the series portion,
R ⁶ represents an alkyl group or an alkoxy group,
n ¹¹ and n ¹² each independently represents 0 or 1,
A ⁸ and A ⁹ are each independently a 1,4-phenylene group which may have a substituent, or (E) -cyclohexane-1,4-diyl group which may have a substituent. Show.
In formula (III),
X ⁵ represents an oxygen atom or —NR ¹¹ — (R ¹¹ represents a hydrogen atom or a monovalent substituent);
R ⁷ represents a hydrogen atom or an alkyl group which may have a substituent,
B ⁵ represents a divalent linking group having 4 or more atoms in the series portion,
R ⁹ represents an alkyl group or an alkoxy group,
n ¹³ and n ¹⁴ each independently represent 0 or 1,
A ¹⁰ and A ¹¹ each independently represents a 1,4-phenylene group which may have a substituent, or (E) -cyclohexane-1,4-diyl group which may have a substituent. Show. ]
(7) A liquid crystal composition comprising the dichroic dye according to any one of (1) to (6).
(8) A liquid crystal element having a liquid crystal phase containing the liquid crystal composition according to (7).

  Since the azo dichroic dye of the present invention has an order parameter (S value) with a high dichroic ratio, it includes a guest-host type liquid crystal composition necessary for realizing a display with a very high contrast and the same. A liquid crystal element can be provided.

It is a schematic sectional drawing in the voltage application state of the phase transition mode guest host type | mold liquid crystal display element which shows an example of the liquid crystal element produced using the azo type dichroic dye of this invention. FIG. 2 is a schematic cross-sectional view of a phase transition mode guest-host type liquid crystal display element showing an example of a liquid crystal element produced using the azo-based dichroic dye of the present invention in a state where no voltage is applied.

  The dichroic dye of the present invention is represented by the formula (I).

(I) [in the formula (I)
Ar ¹ and Ar ² each independently represent an aromatic ring which may have a substituent,
X ¹ and X ² each independently represent an oxygen atom or —NR ⁵ — (R ⁵ is a hydrogen atom or an alkyl group which may have a substituent);
R ¹ and R ² each independently represents a hydrogen atom or an optionally substituted alkyl group, alkenyl group, alkynyl group, or alkoxy group,
L ¹ and L ² represent a direct bond or a divalent linking group,
A ^{1 to} A ⁴ each independently represents a 1,4-phenylene group or (E) -cyclohexane-1,4-diyl group which may have a substituent,
B ¹ and B ² each represent a linking group having 4 or more atoms connected in series,
n ^{1 to} n ⁵ are integers of 1 or more, and when n ^{1 to} n ⁵ are integers of 2 or more, A ¹ , A ³ , A ⁴ , Ar ¹ and Ar ² present in one molecule are May be the same or different,
m ¹ and m ³ are 0 or 1, and m ² is an integer of 0 or more. ]
1. Ar ¹ and Ar ^{2 In the} structural formula (I), Ar ¹ and Ar ² each independently represent an aromatic ring which may have a substituent.

The aromatic ring is not particularly limited as long as it does not impair the effects of the present invention. The aromatic ring is a 5- or 6-membered monocyclic ring or a condensed ring formed by condensation of 2 to 4 hydrogen atoms. Specific examples include a phenylene group, a tolylene group, a xylylene group, a naphthylene group, a quinoline group, a thienylene group, a pyridylene group, a thienothiazole group, and the like. Among these, a 1,4-phenylene group or a 1,4-naphthylene group is preferable because an order parameter (S value) having a high dichroic ratio can be obtained. In particular, when m1 = m2 = m3 = 0, Ar ¹ is preferably a 1,4-phenylene group.

Ar ¹ and Ar ² may have an electron-donating substituent such as an alkoxy group or an alkyl group; or a cyano group, a nitro group, an alkylsulfonyl group, a halogenated alkyl group, or a halogen atom. And an electron-withdrawing substituent such as an alkoxycarbonyl group.
Examples of the alkoxy group as a substituent that Ar ¹ and Ar ² may have include, for example, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, and a tert-butoxy group. Examples thereof include an alkoxy group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, especially 1 to 3 carbon atoms.

Examples of the alkyl group as a substituent that Ar ¹ and Ar ² may have include, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, especially 1 to 3 carbon atoms
Of the alkyl group.
Among electron-donating substituents such as an alkoxy group and an alkyl group which are substituents which Ar ¹ and Ar ² may have, a methyl group or a methoxy group is particularly preferable from the viewpoint of solubility in the host liquid crystal.

Examples of the alkylsulfonyl group as a substituent that Ar ¹ and Ar ² may have include, for example, a methylsulfonyl group, an ethylsulfonyl group, an isopropylsulfonyl group, an n-butylsulfonyl group, an isobutylsulfonyl group, and a sec-butylsulfonyl group. And an alkylsulfonyl group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, especially 1 to 3 carbon atoms, such as a tert-butylsulfonyl group.

Examples of the halogenated alkyl group that is a substituent that Ar ¹ and Ar ² may have include, for example, a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, and the like. 10, preferably a lower fluoroalkyl group having 1 to 4 carbon atoms, especially 1 to 3 carbon atoms.
Examples of the halogen atom which is a substituent that Ar ¹ and Ar ² may have include fluorine, chlorine, bromine and iodine, preferably fluorine, chlorine and bromine.

As the alkoxycarbonyl group that may be substituted by Ar ¹ and Ar ² , a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, an isopropoxycarbonyl group, an n-butoxycarbonyl group, an isobutoxycarbonyl group, 1 to 10 carbon atoms, preferably 1 to 1 carbon atoms such as sec-butoxycarbonyl group and tert-butoxycarbonyl group
4 and especially an alkoxycarbonyl group having 1 to 3 carbon atoms.

As an electron-withdrawing substituent such as a cyano group, a nitro group, an alkylsulfonyl group, a halogenated alkyl group, a halogen atom, and an alkoxycarbonyl group, which are substituents that Ar ¹ and Ar ² may have, these Among these, a cyano group, a trifluoromethyl group, a fluorine atom, and a chlorine atom are particularly preferable from the viewpoint of solubility in the host liquid crystal.

2. X ¹ and X ^{2 In the} formula (I), X ¹ and X ² are each independently an oxygen atom or —NR ⁵ —. Indicates. R ⁵ represents a hydrogen atom or an alkyl group. Examples of the alkyl group of R ⁵ include linear or branched carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group and tert-butyl group. To 10 alkyl groups. Of these, an alkyl group having 1 to 4 carbon atoms and more preferably 1 to 3 carbon atoms is preferable from the viewpoint of solubility.

3. L ¹ and L ^{2 In the} formula (I), L ¹ and L ^{2 each} represent a direct bond or a divalent linking group, but preferably each independently contains a cyclic structure and an azo bond and is a divalent linkage. Indicates a group.
Although it does not specifically limit as a bivalent coupling group which does not contain a cyclic structure and an azo bond, For example, a methylene group, ethylene group, propylene group, isopropylene group, butylene group, isobutylene group, sec-butylene Group, tert-butylene group, hexylene group, octylene group or the like linear or branched alkylene group having 1 to 10 carbon atoms; vinylene group, propenylene group, isopropenylene group, butenylene group, isobutenylene group, sec-butenylene group Group, tert-butenylene group, hexenylene group, octenylene group, etc., linear or branched alkenylene group having 2 to 10 carbon atoms; ethynylene group, propynylene group, isopropynylene group, butynylene group, isobutynylene group, sec-butynylene group , Tert-butynylene group, hexynylene group, octini A straight-chain or branched alkynylene group having 2 to 10 carbon atoms such as an ethylene group; methyleneoxycarbonyl group, ethyleneoxycarbonyl group, propyleneoxycarbonyl group, isopropyleneoxycarbonyl group, tert-butyleneoxycarbonyl group, acetyleneoxy Examples thereof include an ester group having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms such as a group; an ether group; a carbonyl group;

In the structure of the present invention, in order to obtain a higher dichroic ratio order parameter (S value), it is preferable to increase the linearity of the molecule. For that purpose, it is preferable that the number of bonds of the parts having a six-membered ring structure, that is, the series part connecting A ¹ and A ² , A ³ and A ⁴ is sufficiently long. In this case, the term “sufficiently long” means 5 atoms or more, more preferably 7 atoms or more. Moreover, it is also preferable that the portions having a six-membered ring structure are connected by an even number of atoms. In this respect, if a structure in the formula of the present invention (I), ^{A 1} and ^{L 1} and ^X 1 between ^B 1, ^{A 2} and Ar ¹ between ^{A 2,} Ar ² and ^{A 3} For X ² and L ² between and B ² between A ³ and A ⁴ , the number of atoms on the main chain is preferably an even number. Among these, regarding L ¹ and X ¹ , X ² and L ² having two structures between six-membered ring structures, since X ¹ and X ² are oxygen atoms or —NR ⁵ —, the number of atoms on the main chain Will be 1. Therefore, the number of atoms on the main chain of L ¹ and L ² is preferably an odd number.

As specific structures, L ¹ (between A ² and X ¹ ) and L ² (between A ³ and X ² ) are each independently a —CH ₂ — group, —CH ₂ CH ₂ CH _{A 2} -group, a —CH ₂ —C≡C— group, or a —CH (CH ₃ ) — group is particularly preferred.
In particular, when m ¹ = m ² = m ³ = 0, since X ¹ does not exist, L ¹ has an even number of atoms on the main chain, -O-CH _2- , -OC (= O) -, -CH = CH-, -OC (= O)-, -C tri-C- group and the like are preferable.

4). A ¹ , A ² , A ³ and A ^{4 In the} formula (I), A ¹ , A ² , A ³ and A ⁴ are each independently 1,4-phenylene which may have a substituent. (E) -cyclohexane-1,4-diyl group which may have a group or a substituent. As the substituent that A ¹ , A ² , A ³ , and A ⁴ may have,
It is the same as the substituent which Ar < ¹ >, Ar < ² > may have.

5). n ¹ , n ² , n ³ , n ⁴ , n ⁵ , m ¹ , m ² and m ^{3 In} formula (I), n ¹ , n ² , n ³ , n ⁴ and n ⁵ are each independently When an integer of 1 or more and n ¹ , n ² , n ³ , n ⁴ and n ⁵ are 2 or more, 2 or more are present in one molecule of the dichroic dye having the structure represented by the formula (I) A ¹ , Ar ¹ , Ar ² , A ³ , A ⁴ may be the same or different.

M ¹ and m ³ represent 0 or 1. m ² is an integer of 0 or more. When m ² is 2 or more, two or more A ² present in one molecule of the dichroic dye having the structure represented by the formula (I) may be the same or different.
Among these, preferable combinations are m ¹ = m ² = m ³ = 1 or m ¹ = m ² = m ³ = 0.

From the viewpoint of solubility in the host liquid crystal, the total number of n ¹ and m ² , n ⁴ and n ⁵ is 2 respectively.
It is preferable that it is -8, and it is more preferable that it is 3-6.
N ³ is preferably 1 to 5, and more preferably 1 to 4, from the viewpoint of solubility in the host liquid crystal.
Preferred n ² is n ² = 1 when m ¹ = m ² = m ³ = 1.

6). About B ¹ and B ^{2 In the} formula (I), B ¹ and B ² each represent a linking group in which the series part connecting A ¹ and A ² , A ³ and A ⁴ is 4 atoms or more.
Between the 6-membered ring structure and the 6-membered ring structure at the end of the azo dichroic dye having the structure represented by the formula (I) (between A ¹ and A ² and between A ³ and A ⁴ ) A dichroic dye having an order parameter (S value) with a high dichroic ratio can be realized by introducing a linear structure having a large mobility in which the series part connecting them is 4 atoms or more. The reason for having a high dichroic ratio order parameter is that the structure is relatively fixed between A ¹ and A ² , between A ³ and A ⁴ , that is, a six-membered ring structure having a planar shape. By introducing a chain structure with high mobility between the 6-membered ring structures, the 6-membered ring structure at the end is more aligned with the long axis of the host liquid crystal than in the case of a structure connected by only 6-membered rings. This is thought to be because it became easier to arrange in parallel.

B ¹ and B ² are in a range that does not impair the effects of the present invention, and are not particularly limited as long as the series part connecting A ¹ and A ² , A ³ and A ⁴ is 4 atoms or more, but an alkylene group , Alkenylene group, alkynylene group, ester group, ether group or carbonyl group is preferred from the viewpoint of high S value. In particular, B ² is preferably these groups. B ¹
May be a combination of the above groups.

Specifically, examples of the alkylene group include linear or branched alkylene groups having 4 to 10 carbon atoms such as a butylene group, a pentylene group, a hexylene group, a heptylene group, and an octylene group.
Specific examples of the alkenylene group include linear or branched alkenylene groups having 4 to 10 carbon atoms such as a butenylene group, a pentenylene group, a hexenylene group, a heptenylene group, and an octenylene group.

Specific examples of the alkynylene group include linear or branched alkynylene groups having 4 to 10 carbon atoms such as a butynylene group, a pentynylene group, a hexylene group, a heptynylene group, and an octynylene group.
Specific examples of the ester group include 4 carbon atoms such as ethoxycarbonyl group, propyloxycarbonyl group, sec-, iso-, tert-butoxycarbonyl group, pentyloxycarbonyl group, and the like.
-20, preferably 4-10 groups having an ether bond.

Moreover, as what combined these, C4-C10 linear or branched form, such as a 1, 2- dioxyethylene group, a 1, 3- dioxypropylene group, and a 1, 4- dioxybutylene group. An alkylenedioxy group; a linear or branched alkylene carbonate group having 4 to 10 carbon atoms such as ethylene carbonate and butylene carbonate;
As B ¹ and B ² , those in which the number of bonds in the series part connecting A ¹ and A ² , A ³ and A ⁴ is an even number are more preferable for increasing the S value. Specifically, —CH ₂ CH ₂ CH ₂ CH ₂ — group, —OCH ₂ CH ₂ O— group, —CH ₂ CH ₂ —C≡C— group (example in which the series part is 4 atoms), —OCH ₂ CH ₂ CH ₂ CH ₂ O -Group, -C≡C-CH ₂ CH ₂ CH ₂ CH ₂ -group, -C≡C-CH ₂ CH ₂ CH ₂ O- group (example in which the series part is 6 atoms), and -OCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O-group (example in which the series portion is 8 atoms) and the like. In addition, when the number of bonds in the series part connecting A ¹ and A ² , A ³ and A ⁴ is 5 or more, more preferably 7 or more, even if an odd number is used, the linearity is high as viewed from the whole molecule. Similar effects can be expected. The upper limit is not particularly limited, but is preferably 20 or less because of difficulty in synthesis.

7). About R ¹ and R ^{2 In the} formula (I), R ¹ and R ² are each independently a hydrogen atom, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent. , An alkynyl group which may have a substituent, and an alkoxy group which may have a substituent. Examples of the alkyl group include a straight chain having 1 to 10 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a hexyl group, and an octyl group. A branched one is preferable, among which a linear one is more preferable, and a linear alkyl group having 3 to 8 carbon atoms is particularly preferable from the viewpoint of increasing the solubility. Alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, hexyloxy, octyloxy, etc. 10 to 10 linear or branched ones are preferable, among which linear ones are more preferable, and linear alkoxy groups having 3 to 8 carbon atoms are particularly preferable from the viewpoint of increasing the solubility. Specific examples of the alkenylene group include linear or branched alkenylene groups having 4 to 10 carbon atoms such as a butenylene group, a pentenylene group, a hexenylene group, a heptenylene group, and an octenylene group. Specific examples of the alkynylene group include linear or branched alkynylene groups having 4 to 10 carbon atoms such as a butynylene group, a pentynylene group, a hexylene group, a heptynylene group, and an octynylene group.

  Alkyl group which may have substituent, alkenyl group which may have substituent, alkynyl group which may have substituent, substituent of alkoxy group which may have substituent Is not particularly limited, but includes electron-donating substituents such as alkoxy groups and alkyl groups; or electron-withdrawing substituents such as cyano groups, nitro groups, halogenated alkyl groups, halogen atoms, and alkoxycarbonyl groups. The number of carbon atoms including the substituent is preferably in the above-mentioned range for each group.

8). Formula (II) and Formula (III)
Among the structures represented by the formula (I) of the present invention, particularly preferably, the right side of the azo bond after repeating the repeating unit containing Ar ² in the formula (I) n ³ −1 times is represented by the following formula: (II) or having a partial structure represented by formula (III).

[In the formula (II),
X ⁴ represents an oxygen atom or —NR ¹⁰ — (R ¹⁰ is a hydrogen atom or a monovalent substituent);
R ⁸ represents a hydrogen atom or an alkyl group which may have a substituent,
B ⁴ represents a divalent linking group having 4 or more atoms in the series portion,
R ⁶ represents an alkyl group or an alkoxy group,
n ¹¹ and n ¹² each independently represents 0 or 1,
A ⁸ and A ⁹ each independently represents a 1,4-phenylene group which may have a substituent, or (E) -cyclohexane-1,4-diyl group which may have a substituent. Show.
In formula (III),
X ⁵ represents an oxygen atom or —NR ¹¹ — (R ¹¹ represents a hydrogen atom or a monovalent substituent);
R ⁷ represents a hydrogen atom or an alkyl group which may have a substituent,
B ⁵ represents a divalent linking group having 4 or more atoms in the series portion,
R ⁹ represents an alkyl group or an alkoxy group,
n ¹³ and n ¹⁴ each independently represent 0 or 1,
A ¹⁰ and A ¹¹ each independently represents a 1,4-phenylene group which may have a substituent, or (E) -cyclohexane-1,4-diyl group which may have a substituent. Show. ]

9. X ⁴ and X ^{5 In the} structural formula (II), X ⁴ represents an oxygen atom or a —NR ¹⁰ — group. X ⁵ in the structural formula (III) represents an oxygen atom or a —NR ¹¹ — group Indicates. R ¹⁰ and R ¹¹ each independently represent a hydrogen atom or an alkyl group which may have a substituent.
The alkyl group of R ¹⁰ and R ¹¹ is linear or branched such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, hexyl group, octyl group, etc. -Like alkyl groups. Among these, from the viewpoint of increasing the solubility, linear or branched ones having 1 to 10 carbon atoms are preferable, among which linear ones are more preferable, and linear alkyl having 3 to 8 carbon atoms. The group is particularly preferred.

10. About B ⁴ and B ^{5 In} formula (II) and formula (III), B ⁴ and B ⁵ each independently have 4 or more atoms in series connecting the 1,4-phenylene groups at both ends. A divalent linking group is shown. Examples of the divalent linking group has the same meaning as those exemplified by B ¹ of formula (I), and preferred groups are also the same meanings.

11. About R ⁶ and R ^{7 In the} formula (II) and the formula (III), R ⁶ and R ⁷ each independently represents an alkyl group or an alkoxy group.
Examples of the alkyl group include a straight chain having 1 to 10 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a hexyl group, and an octyl group. A branched one is preferable, among which a linear one is more preferable, and a linear alkyl group having 3 to 8 carbon atoms is particularly preferable for improving solubility. Alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, hexyloxy, octyloxy, etc. 10 to 10 linear or branched ones are preferable, among which linear ones are more preferable, and linear alkoxy groups having 3 to 8 carbon atoms are particularly preferable because of high solubility.

12 Regarding A ⁸ , A ⁹ , A ¹⁰ and A ^{11 In the} formulas (II) and (III), A ⁸ , A ⁹ , A ¹⁰ and A ¹¹ may each independently have a substituent. 1,4-phenylene group or (E) -cyclohexane-1,4-diyl group which may have a substituent is shown. The substituents that A ⁸ , A ⁹ , A ¹⁰ and A ¹¹ may have are each independently, for example, an electron-donating substituent such as an alkoxy group or an alkyl group; or a cyano group, a nitro group or an alkyl group. Examples thereof include electron-withdrawing substituents such as a sulfonyl group, a halogenated alkyl group, a halogen atom, and an alkoxycarbonyl group. Specifically, these are the same as those described for Ar ¹ , and preferred groups are also the same.

13. R ⁸ and R ⁹ for R ⁸ and R ⁹ each independently represent a hydrogen atom or a monovalent substituent. The monovalent substituent is not particularly limited as long as the effects of the present invention are not impaired. For example, an electron-donating substituent such as an alkoxy group or an alkyl group; or a cyano group, a nitro group, an alkylsulfonyl group, Examples thereof include electron-withdrawing substituents such as halogenated alkyl groups, halogen atoms, and alkoxycarbonyl groups.
Preferable examples of these substituents are the same as those mentioned for the substituent that Ar ¹ may have, and preferable groups are also the same.

14 n ¹¹ , n ¹² , n ¹³ and n ^{14 In} formula (II) and formula (III), n ¹¹ , n ¹² , n ¹³ and n ¹⁴ each independently represent 0 or 1. From the viewpoint of the order parameter (S value) of contrast,
Further, from the viewpoint of enhancing the solubility in the host liquid crystal, it is preferable that either n ¹¹ or n ¹² , or any of n ¹³ or n ¹⁴ is at least 1.

15. Molecular Weight The dichroic dye of the present invention represented by the formula (I) described above usually has a molecular weight of 4000 or less, preferably 3000 or less, from the viewpoint of solubility in the host liquid crystal and response speed. The lower limit is not particularly ^{limited, m 1 = m 2 = m} 3 = 1 if 660 or ^{more, m 1 = m 2 = m} 3 = 0 If more than 500 are preferred.

16. Specific Examples Specific examples of the dichroic dye represented by the formula (I) are illustrated below, but the present invention is not limited to these unless it exceeds the gist.

17. Synthesis Method Hereinafter, a method for synthesizing the dichroic dye represented by the formula (I) of the present invention will be described with some examples. For example, in the case of a structure of m ¹ = m ³ = 1 and n ² = 1, intermediates (V), (VI) and (VII
) Can be synthesized by azo coupling reaction. In the case of m ¹ = m ² = m ³ = 0, intermediate (VIII) and intermediate (IX) can be obtained by mixing and reacting at a desired molar ratio. An example of this reaction is shown in the chemical formula below. Regarding the structure of formula (I), the case where n ² is 2 or more is shown as the most easily synthesized method. These reaction conditions are not particularly limited, and a known method may be used. For example, JP-A-58-38
The method described in Japanese Patent No. 756 can be applied.

Each intermediate (V) to intermediate (IX) can also be synthesized by a known method, for example, by the method described in JP-A-58-38756. Intermediate (VII) and intermediate (IX) can be synthesized, for example, by the method described in the examples. In addition, A ¹ to A ⁴ , Ar ¹ , Ar ² , X ¹ , X ² , L ¹ , L ² , R ¹ , R ² , n ¹ to n ⁵ used for the intermediates (V) to (IX)
, M ¹ to m ³ have the same meanings as shown in formula (I).

18. Liquid Crystal Composition One or two or more of the dichroic dyes of the present invention are added to pages 154 to 192 of the “Liquid Crystal Device Handbook” (Nikkan Kogyo Shimbun, published in 1989) edited by the Japan Society for the Promotion of Science, 142nd Committee. Known methods for various host liquid crystal compounds such as biphenyl, phenylcyclohexane, phenylpyrimidine, cyclohexylcyclohexane and the like which show nematic or smectic phases described in pages 715 to 722, or host liquid crystal compositions containing these compounds The liquid crystal composition can be easily prepared by mixing in step (b).

Examples of such a liquid crystal compound include compounds described in JP-A-3-14892. The type of the preferred host liquid crystal varies depending on the driving method. For example, in the case of an active matrix system, a fluorine-based liquid crystal is preferable.
The content ratio of the dichroic dye of the present invention in the liquid crystal composition is not particularly limited, but is usually 0.05 to 10% by weight including the case where two or more kinds are contained. It is preferably 1 to 5% by weight.

19. Host liquid crystal As a host liquid crystal material used in the guest-host type liquid crystal composition of the present invention, the following formula (X) to
Np type liquid crystal compounds and Nn type liquid crystal compounds represented by the formula (XIV) can be given.

In formulas (X) to (XIX), E represents a cyclohexane ring, a benzene ring, a dioxane ring, or a pyrimidine ring, and q represents an integer of 1 to 3. Z represents a single bond, —CO—O— group, —CH ₂ CH ₂ — group, —CH═CH— group, or —C≡C— group. D ¹ and D ³ each independently represent a hydrogen atom or a halogen atom such as a fluorine atom or a chlorine atom, and D ² represents a halogen atom such as a fluorine atom or a chlorine atom, or a halogen atom such as a fluorine atom or a chlorine atom. A C1-C7 alkyl group as a substituent, also an alkenyl group, an alkoxy group, a substituted alkyl group, a substituted alkenyl group, a cyclohexyl group having a substituted alkoxy group as a substituent, or a substituted alkyl group thereof, substituted The phenyl group which has an alkenyl group and a substituted alkoxy group as a substituent is shown. D ⁷ and D ⁸ each independently represent a cyano group or a halogen atom such as a fluorine atom or a chlorine atom. D ¹¹ and D ^{13 each} represent a cyano group. D ⁴ , D ⁵ , D ⁶ , D ⁹ , D ¹⁰ , D ¹² , and D ¹⁴ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 1 to 10 carbon atoms. Or an alkoxyalkyl group having 2 to 10 carbon atoms.
The host liquid crystal material used for the guest-host type liquid crystal composition of the present invention preferably has the following characteristics.

(NI point)
The nematic phase-isotropic liquid phase transition temperature (NI point) is 60 ° C. or higher, preferably 80 ° C. or higher, and 130 ° C. or lower, preferably 110 ° C. or lower. When used in combination with the dye of formula (I) of the present invention, the operating temperature range can be widened by setting the NI point to the above range. Moreover, the response performance improves by not exceeding an upper limit.

(Dielectric anisotropy Δε)
The absolute value of Δε is 2 or more, preferably 3 or more, and 20 or less, preferably 10 or less. When used in combination with the dye of the formula (I) of the present invention, the drive voltage can be lowered by setting Δε within the above range. On the other hand, if it is within the above upper limit range, the viscosity of the host liquid crystal does not increase, and high response performance can be expected.

Further, the liquid crystal compound may contain additives such as an optically active substance such as cholesteryl nonanoate, an ultraviolet absorber, and an antioxidant.
Further, the dichroic dye composition of the present invention has a particularly good dichroic ratio in combination with a host material containing a fluorine compound.
The dichroic dye of the present invention or a liquid crystal composition containing the same preferably has a high order parameter (S value) of 0.80 or more, more preferably 0.84 or more, and most preferably 0.86 or more. The liquid crystal composition of the present invention can be suitably used as various electro-optical devices such as display elements for computers, watches, calculators, etc., electro-optical shutters, electro-optical apertures, optical communication optical path switching switches, optical modulators and the like. it can.

The order parameter (S value) of the contrast of the dye can be obtained from the following formula described in “Liquid Crystal Device Handbook” edited by the 142th Committee of the Japan Society for the Promotion of Science based on spectroscopic measurement.
S = (A // − A⊥) / (2A⊥ + A //)
Here, “A //” and “A⊥” are the absorbance of the dye with respect to light polarized parallel and perpendicular to the alignment direction of the liquid crystal, respectively, and the S value is theoretically in the range of 0 to 1. The closer the value is to 1, the more the contrast as a guest-host type liquid crystal element is improved.

20. Liquid Crystal Element By sandwiching a liquid crystal layer containing the liquid crystal composition containing the dichroic dye of the present invention between two substrates with electrodes, at least one of which is transparent, Shoichi Matsumoto and Ryo Tsunoda “ Latest Technology of Liquid Crystals ”(Industry Research Committee, published in 1983), p. L. Heilmeier-type guest hosts described in Fergason, SID85Digest, 68 (1985), “Liquid Crystal Device Handbook” (Nikkan Kogyo Shimbun, 1989) pages 315-329, etc. A guest host effect such as a transfer guest host was used. As described above, various modes of the liquid crystal element can be used in the present invention. However, in the phase transition mode obtained by adding an optically active substance to the nematic liquid crystal composition, a polarizing plate is not used. Since the contrast is high and the display is bright, it is particularly preferable as a reflective liquid crystal display element.

  As an example of the liquid crystal element of the present invention, FIGS. 1 and 2 are schematic cross-sectional views of an active drive type phase change mode guest-host type liquid crystal display element. FIG. 1 shows a voltage application state of the liquid crystal display element, and FIG. 2 shows a voltage non-application state. In the figure, 1 is incident light, 3 is a transparent glass plate, 4 is a transparent electrode, 5 is an alignment film, 6 is a liquid crystal compound molecule, 7 is a dichroic dye molecule, 9 is a reflective layer, and 10 is reflected light.

  When no voltage is applied (FIG. 2), the liquid crystal compound molecule 6 exhibits a cholesteric phase, and the dichroic dye molecule 7 also exhibits a cholesteric structure together with the liquid crystal compound molecule 6. Therefore, even if the incident light 1 is natural light, the polarizing plate Is absorbed by the dichroic dye molecule 7 without using. When a voltage is applied (FIG. 1), the liquid crystal compound molecules 6 and the dichroic dye molecules 7 are aligned in the direction of the electric field, so that light is transmitted and reflected by the reflective layer 9. Thus, in a liquid crystal element, light transmission and absorption can be controlled by the presence or absence of an electric field.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to an Example, unless the summary is exceeded.

  [Intermediate Synthesis 1 (Synthesis of Intermediate M01 Used in Comparative Example 2)]

Intermediate M01 was synthesized by the method described in JP-A-2009-7486.
[Intermediate Synthesis 2 (Synthesis of Intermediate M04 Used in Comparative Example 5)]

Intermediate M04 was synthesized by the method described in JP-A-2009-7485.
[Intermediate Synthesis 3 (Synthesis of Intermediate M05 used in Comparative Example 5)]

Intermediate M05 was synthesized by the method described in JP-A-2009-7485.
[Intermediate Synthesis 4 (Synthesis of Intermediate M20 used in Example 2 and Example 4 and Intermediate M16-19 leading to M20)]

<Synthesis of Intermediate M16>
Intermediate M07 (Kanto Kagaku, 7.5 g 30.6 mmol) and 1,4-dibromobutane (19.8 g, 91.8 mmol, 3MR) were diluted in acetone (60 ml, 30.6 mmol) and potassium carbonate (8.5 g, 61.2 mmol, 2MR) ) Was added and heated to reflux for 18 hours. The reaction solution was cooled to room temperature, and the filtrate obtained by filtration was concentrated, methanol (150 ml) was added, and the mixture was vigorously stirred under ice cooling. The precipitated solid was filtered to obtain Intermediate M16 (9.62 g, yield 82%) as a white solid.

It was confirmed that the following peak was obtained by ¹ H-NMR (400 MHz, CDCl ₃ ) to obtain the intermediate M16. : 7.12-7.16 (m, 2H), 6.82-6.86 (m, 2H), 4.00 (t, J = 6.0Hz, 2H), 3.51 (t, J = 6.8Hz, 2H), 2.39-2.47 (m, 1H ), 2.05-2.12 (m, 2H), 1.87-1.98 (m, 6
H), 1.21-1.48 (m, 13H), 1.00-1.11 (m, 2H), 0.92 (t, J = 7.0Hz, 3H)

<Synthesis of Intermediate M17>
Intermediate M09 (Tokyo Kasei, 15.0 g, 70.0 mmol) was diluted in ethanol (300 ml, 20VR), and 98% sulfuric acid (0.5 ml) was added and reacted under reflux for 16 hours. The reaction solution was cooled to room temperature, ethanol was distilled off, and the precipitated solid was washed with hexane (50 ml) and ethyl acetate (10 ml) to obtain intermediate M10 (14.3 g, yield 85%) as a white solid. I got it.

It was confirmed by ¹ H-NMR (400 MHz, CDCl ₃ ) that the following peak was obtained to obtain Intermediate M10. : 8.10-8.11 (m, 2H), 7.62-7.64 (m, 2H), 7.54-7.56 (m, 2H), 6.95-6.97 (m, 2H), 4.40-4.45 (m, 2H), 1.44 (t, J = 7.2Hz, 3H).
This intermediate M10 (3.49 g, 14.4 mmol) and intermediate M16 (5.50 g, 14.4 mmol) were diluted in N, N-dimethylformamide (50 ml, 14VR), and potassium carbonate (3.98 g, 28.8 mmol, 2MR) was diluted. Add 60
The mixture was heated to 0 ° C. and reacted for 1 hour. After cooling to room temperature, water (50 ml) was added, and the precipitated solid was filtered and washed with methanol (50 ml) to obtain intermediate M17 (8.01 g, LCarea 97%) as a white solid.

<Synthesis of Intermediate M18>
LiAlH ₄ (1.09 g, 28.8 mmol, 2MR) was suspended in dehydrated THF (Kanto Chemicals, 405 VR) ml), and dehydrated THF (40 ml, 5 VR) of intermediate M17 (7.82 g, 14.4 mmol) was cooled with ice. ) The suspension solution was added dropwise little by little. The reaction was warmed to room temperature, reacted for another 1 hour, and then slowly added dropwise to ice-cooled 1N aqueous hydrochloric acid (160 ml). This solution was returned to room temperature, extracted with chloroform (200 ml), the organic layer was dried over magnesium sulfate, and the solvent was distilled off. Intermediate M18 (5.74 g, 80% yield) was obtained as a white solid.

<Synthesis of Intermediate M19>
Intermediate M18 (5.7 g, 11.4 mmol) was diluted in chloroform (60 ml, 10VR), and triphenylphosphine (4.49 g, 17.1 mmol) and carbon tetrabromide (5.31 g, 6.0 mmol) were added to react for 12 hours. did. Methanol (120 ml) was added dropwise to the reaction solution, and the precipitated solid was filtered to obtain Intermediate M19 (5.78 g, yield 90%) as a pale yellowish white solid.

<Synthesis of Intermediate M20>
Intermediate M19 (5.7 g, 10.3 mmol) was diluted in N, N-dimethylformamide (57 ml, 10VR), potassium carbonate (1.71 g, 12.4 mmol, 1.2 MR) was added and reacted at 60 ° C. for 1 hour. It was. The reaction solution was cooled to room temperature, water (100 ml) was slowly added dropwise, and the precipitated solid was filtered and methanol (20 ml)
The crystals were washed with Intermediate M20 (5.60 g, LCaraea 92%, yield 87%) was obtained as white crystals.

[Intermediate Synthesis 5 (Intermediates M08 and 11-13 leading to Intermediates M14 and M14 used in Examples 1 and 3)
Synthesis)]

<Synthesis of Intermediate M08>
Intermediate M08 was obtained in the same manner as in the synthesis of Intermediate M16 except that 1,6-dibromohexane was used in place of 1,4-dibromobutane.
<Synthesis of Intermediate M11>
Intermediate M11 was obtained in the same manner as in the synthesis of Intermediate M17 except that Intermediate M08 was diluted with N, N-dimethylformamide instead of Intermediate M16.

<Synthesis of Intermediate M12>
Intermediate M12 was obtained in the same manner as the synthesis of intermediate M18, except that a dehydrated THF suspension of intermediate M11 was added dropwise little by little instead of intermediate M17.
<Synthesis of Intermediate M13>
Intermediate M13 was obtained in the same manner as in the synthesis of Intermediate M19 except that Intermediate M12 was used instead of Intermediate M18.

<Synthesis of Intermediate M14>
Intermediate M14 was obtained in the same manner as in the synthesis of Intermediate M20 except that Intermediate M13 was used instead of Intermediate M19.
[Intermediate Synthesis 6 (Synthesis of Intermediate M22 used in Example 3)]

Intermediate M22 was synthesized by the method described in JP 2010-155924 A.
[Intermediate Synthesis 7 (Synthesis of Intermediate M23 used in Example 4)]

Intermediate M23 was synthesized by the method described in JP 2010-155924 A.
[Intermediate Synthesis 8 (Synthesis of Intermediate M24 to Intermediate M25 and M25 Used in Example 5)]

Intermediate M24 was synthesized by the method described in JP-A-2009-007485. Intermediate M25 was synthesized from intermediate M24 by the method described in JP-A-2009-007486.
[Intermediate Synthesis 9 (Synthesis of Intermediate M26 used in Example 6 and Intermediate M27 used in Example 5)]

<Synthesis of Intermediate M27>
Intermediate M34 was obtained in the same manner as in the synthesis of intermediate M16 except that intermediate M33 (manufactured by Synthon Chamical) was used instead of intermediate M07.
Intermediate M35 was obtained in the same manner as intermediate M17 except that intermediate M34 was diluted with N, N-dimethylformamide instead of intermediate M16.

Intermediate M36 was obtained in the same manner as intermediate M18 except that a dehydrated THF suspension of intermediate M35 was added dropwise little by little instead of intermediate M17.
Intermediate M26 was obtained in the same manner as in the synthesis of Intermediate M19 except that Intermediate M36 was used instead of Intermediate M18.
Intermediate M27 was obtained in the same manner as in the synthesis of intermediate M20 except that intermediate M26 was used instead of intermediate M19.

   [Intermediate Synthesis 10 (Synthesis of Intermediate M28 used in Example 6)]

<Synthesis of Intermediate M28>
Intermediate M28 was synthesized from intermediate M24 by the method described in JP-A-2009-007486.
<Synthesis of the implementation compound>
[Example 1]

Example Compound 1 was synthesized by using the intermediate M31 (manufactured by Pyram) and the intermediate M14 by the method described in JP-A-2009-007486.
In Example Compound 1, R ¹ is a pentyl group, n ¹ = 2 and A ¹ is a 1,4-phenylene group (E
) -Cyclohexane-1,4-diyl groups, m ¹ = 1 and B ¹ is —OCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O—, m ² = 2 and A ² is 1, 4-phenylene group, L ¹ is a methylene group having an odd number of atoms ¹ on the main chain, m ³ = 1, X ¹ is —NH—, n ² = 1 and Ar ¹ is 1,4-naphthylene A methylene group wherein n ³ = 3, Ar ² is 1,4-phenylene group and 1,4-naphthylene group, X ² is —NH—, and L ² is an odd number of atoms on the main chain N ⁴ = 2 and A ³ is 1,4-phenylene group, B2 is —OCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O— group, n ⁵ = 2 and A ⁴ is 1,4-phenylene group And (E) -cyclohexane-1,4-diyl group one by one, R ² is a pentyl group, and is a structure included in formula (I).
[Example 2]

Example Compound 2 was synthesized using Intermediate M31 and Intermediate M20 by the method described in JP-A-2009-007486.
In Example Compound 2, R ¹ is a pentyl group, n ¹ = 2 and A ¹ is a 1,4-phenylene group (E
) -Cyclohexane-1,4-diyl group, m ¹ = 1, B ¹ is —OCH ₂ CH ₂ CH ₂ CH ₂ O— group, m ² = 2 and A ² is 1,4-phenylene group , L ¹ is a methylene group of 1 with an odd number of atoms on the main chain, m ³ = 1, X ¹ is —NH—, n ² = 1 and Ar ¹ is a 1,4-naphthylene group, n ³ = 3, Ar ² is a 1,4-phenylene group and a 1,4-naphthylene group, X ² is —NH—, L ² is a methylene group having an odd number of atoms on the main chain, and n ⁴ = 2 and A ³ is 1,4-phenylene group, B2 is —OCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O— group, n ⁵ = 2 and A ⁴ is 1,4-phenylene group and (E) - cyclohexane over 1,4-diyl group one by one, R ² is pentyl group, a structure included in the formula (I).
The compounds of Examples 1 and 2 are dichroic dyes corresponding to formula (I).
[Example 3]

Intermediate M22 (630 mg, 1 mmol) was diluted with dimethylformamide: N-methyl-2-pyrrolidone = 17: 8 (63 ml, 100 VR), cooled in an ice bath, 35% aqueous hydrochloric acid (0.28 ml, 3MR), Saturated aqueous solution of sodium nitrite (70mg, 1.05mmol, 1.05MR) was added slowly and slowly, keeping the temperature below 5 ° C.
A diazonium salt solution was used. In a separate container, intermediate M14 (653 mg, 1 mmol), THF (63 ml, 100 VR)
Was cooled in an ice bath, and the above-mentioned diazonium salt solution was slowly added dropwise at 5 ° C. or lower. After reacting for 30 minutes, the temperature was raised to room temperature, and sodium acetate (3.0 g) and water (50 ml) were added dropwise to filter the precipitated solid. The resulting residue was purified with a silica gel column (adsorption method, Kanto Science N60 neutral, 200 ml, chloroform 100%), the distillate was concentrated, and chloroform (100 ml) and ethyl acetate (200 ml) were added. Washing and filtration gave Example Compound 3 (370 mg, 30% yield) as a black solid. In Example Compound 3, R ¹ is a pentyl group, n ¹ = 2 and A ¹ is ^one 1,4-phenylene group and one (E) -cyclohexane-1,4-diyl group, m ¹ = 0, m ² = 0, L ¹ is a direct bond, m ³ = 0, n ² = 1, Ar ¹ is a 1,4-phenylene group, n ³ = 3, Ar ² is a 1,4-naphthylene group, and X ² is —NH—, L ² is a methylene group having an odd number of atoms on the main chain, n ⁴ = 2; A ³ is a 1,4-phenylene group; and B 2 is —OCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O— group, n ⁵ = 2 and A ⁴ is 1,4-phenylene group and (E) -cyclohexane-1,4-diyl group one by one, R ² is pentyl group, It is a structure included in I).
[Example 4]

Example compound 4 was synthesized in the same manner as in Example 3, except that intermediate M23 was used instead of intermediate M22, and intermediate M20 was used instead of intermediate M14. In Example Compound 4, R ¹ is a pentyl group,
n ¹ = 2 and A ¹ is ^one 1,4-phenylene group and one (E) -cyclohexane-1,4-diyl group, m ¹ = 0, m ² = 0, L ¹ is a direct bond, m 1 ³ = 0, n ² = 1, Ar ¹ is 1,4-phenylene group, n ³ = 2 and Ar ² is 1,4-naphthylene group, X ² is —NH—, L ²
Is a methylene group having an odd number of atoms 1 on the main chain, n ⁴ = 2; A ³ is a 1,4-phenylene group; B2 is an —OCH ₂ CH ₂ CH ₂ CH ₂ O— group; n ⁵ = 2 ^{a 4} is a 1,4-phenylene group (E) - cyclohexane over 1,4-diyl group one by one, R ² is pentyl group, a structure included in the formula (I).
[Example 5]

Example compound 5 was synthesized in the same manner as in Example 3, except that intermediate M25 was used instead of intermediate M22, and intermediate M27 was used instead of intermediate M14. In Example Compound 5, R ¹ is a pentyl group, n
¹ = 2, A ¹ is ^one 1,4-phenylene group and one (E) -cyclohexane-1,4-diyl group, m ¹ = 0, m ² = 0, L ¹ is a direct bond, m ³ = 0, n ² = 1, Ar ¹ is 1,4-phenylene group, n ³ = 2 and Ar ² is 1,4-naphthylene group, X ² is —NH—, L ² is the number of atoms on the main chain Is a methylene group of 1 which is an odd number, n ⁴ = 2 and A ³ is a 1,4-phenylene group, B 2 is a —OCH ₂ CH ₂ CH ₂ CH ₂ O— group, n ⁵ = 2 and A ⁴ is 1 , 4-phenylene group and (E) -cyclohexane-1,4-diyl group one by one, R ² is a heptyl group, and is a structure included in the formula (I).
[Example 6]

Intermediate M28 (0.150 g, 0.258 mmol) and intermediate M26 (0.152 g, 0.258 mmol) were dissolved in N, N-dimethylformamide (5 mL), potassium carbonate (0.071 g, 0.516 mmol) was added, and 60 The mixture was stirred at ° C for 2 hours. The reaction solution was returned to room temperature, water (10 mL) was added, the aqueous layer was extracted with chloroform, and the organic layer was washed with a saturated aqueous sodium chloride solution. The organic layer was dried over anhydrous sodium sulfate, the filtrate after filtration was concentrated, and the resulting residue was purified by column chromatography (N60 silica gel neutral, chloroform: 200 mL, manufactured by Kanto Kagaku Co., Ltd.). The solvent was gradually distilled off with an evaporator. The precipitated solid was collected by filtration, and Example compound 6 (25 mg, yield)
9%). In Example Compound 6, R ¹ is a pentyl group, n ¹ = 2 and A ¹ is ^one 1,4-phenylene group and one (E) -cyclohexane-1,4-diyl group, m ¹ = 0, m ² = 0, L ¹ is a direct bond, m ³ = 0, n ² = 1, Ar ¹ is a 1,4-phenylene group, n ³ = 2 and A
r ² is a 1,4-naphthylene group and a 1,4-phenylene group, X ² is an oxygen atom, L ² is a methylene group having an odd number of atoms on the main chain, and n ⁴ = 2 and A ³ is 1,4-phenylene group, B2 is —OCH ₂ CH ₂ CH ₂ CH ₂ O— group, n ⁵ = 2 and A ⁴ is 1,4-phenylene group and (E) -cyclohexane-1,4-diyl One group at a time, R ² is a heptyl group, and is a structure included in formula (I).
[Comparative Example 1]

Comparative compound 1 was synthesized by the method described in JP-A-2009-007486.
[Comparative Example 2]

Comparative Example Compound 2 was synthesized from Intermediate M01 and Intermediate M31 by the method described in JP-A-2009-007486.
[Comparative Example 3]

Comparative compound 3 was synthesized by the method described in JP 2010-155924 A.
[Comparative Example 4]

Comparative compound 4 was synthesized by the method described in JP-A-2009-007485.
[Comparative Example 5]

Comparative Example Compound 5 was synthesized from Intermediate M04 and Intermediate M05 by the method described in JP-A-2009-007486.

[Evaluation of λmax and order parameter (S value) of dichroic dye]
<Evaluation of Example Compounds 1, 2, 6 and Comparative Examples 1, 2, 5>
The obtained dichroic dyes “Example Compounds 1, 2, 6” and “Comparative Example Compounds 1, 2, 5” are Nn-type liquid crystal mixtures containing a fluorine-based compound as a main component and having an NI point of 90 ° C. A guest-host liquid crystal composition was prepared by dissolving 0.1% by weight in each of those having Δε of −4.2. The glass substrate with a transparent electrode coated, cured, and rubbed with a polyimide resin was opposed to this, and sealed in a cell with a gap of 50 μm configured so that the liquid crystal was aligned in parallel. The absorbance (A //) for linearly polarized light parallel to the orientation direction of the colored cell and the absorbance (A⊥) for polarized light perpendicular to the orientation direction were measured, and the order parameter (S value) at the absorption peak (λmax) was determined. It calculated | required from the following formula.
S = (A // − A⊥) / (2A⊥ + A //)

<Evaluation of Example Compounds 3, 4, 5 and Comparative Example Compounds 3, 4>
The obtained dichroic dyes “Example compounds 3, 4, 5” and “Comparative example compounds 3, 4” are Nn-type liquid crystal mixtures containing a fluorine-based compound as a main component, the NI point is 90 ° C., and Δε is − Each solution was dissolved in 4.2 at a concentration of 0.5% by weight to prepare a guest-host liquid crystal composition. This is a glass substrate with a transparent electrode that is coated, cured, and rubbed with a polyimide resin.
The liquid crystal was sealed in a cell having a gap of 12 μm configured to have vertical alignment. A function generator 33120A (Agilent) is used to amplify a rectangular wave 1Kz5V with a bipolar power supply (Kikusui Electronics), and the absorbance (A20V) when an amplitude of 20V is applied and the absorbance (A0V) when no voltage is applied are measured. The order parameter (S value) at the absorption peak (λmax) was determined from the following equation.
S = (A20V-A0V) / (2A0V + A20V)
The results are shown in Table 1.

From Table 1, the compounds of the examples in which a mobile linear structure was introduced between the 6-membered ring structure and the 6-membered ring structure at both ends or one end of the side chain part of the azo dichroic dye were 6-membered. It turns out that the value of S value can be improved rather than the comparative example compound which linked the ring structure directly.
As a general rule in this field, increasing the 6-membered ring structure in which the side chain is in series increases the S-value but decreases the solubility. However, the S value is improved in series of 6-membered ring structures up to 3 groups as is clear from the comparison of Comparative Examples 1 and 2, and in Comparative Example 2, both the S value and the solubility are higher than those of Comparative Example 1. It is falling. However, in Examples 1 and 2, by introducing the B1 and B2 portions, the S value can be improved from 0.86 in Comparative Example 2 to 0.89 and 0.88, respectively, and in Example 2, the solubility is also improved. Yes.
In addition, the comparison between Comparative Example 3 and Example 3, and the comparison between Comparative Example 4 and Example 5 (I think that Example 3 is easier to use a new product), the main skeleton that determines the color is common. However, it can be seen that the number of 6-membered ring structures has increased by two or two, and the solubility should decrease, but the solubility is rather improved, and the S value is further improved. Further, in the comparison between Comparative Example 5 and Example 6, the total number of 6-membered ring structures in the side chain portion is the same, but the S value and the solubility are improved due to the introduction of the B1 and B2 portions. Recognize.
Thus, it can be seen that the present invention is an epoch-making one that contributes to the improvement of the S value, which had hit the peak in the conventional method.

1; Incident light
3; Transparent glass substrate
4; Transparent electrode
5: Alignment film
6; Liquid crystal compound molecules
7; Dichroic dye molecule
9; reflective layer
10; Reflected light

Claims (8)

(1) A dichroic dye represented by the following formula (I).

[In the formula (I),
Ar ¹ and Ar ² each independently represent an aromatic ring which may have a substituent,
X ¹ and X ² each independently represent an oxygen atom or —NR ⁵ — (R ⁵ is a hydrogen atom or an alkyl group which may have a substituent);
R ¹ and R ² each independently represents a hydrogen atom or an alkyl group, an alkenyl group, an alkynyl group or an alkoxy group, which may have a substituent,
L ¹ and L ² represent a direct bond or a divalent linking group,
A ^{1 to} A ⁴ each independently represents a 1,4-phenylene group or (E) -cyclohexane-1,4-diyl group which may have a substituent,
B ¹ and B ² each represent a linking group having 4 or more atoms connected in series,
n ^{1 to} n ⁵ are integers of 1 or more, and when n ^{1 to} n ⁵ are integers of 2 or more, A ¹ , A ³ , A ⁴ , Ar ¹ and Ar ² present in one molecule are May be the same or different,
m ¹ and m ³ are 0 or 1, and m ² is an integer of 0 or more. ] ^{2. The} dichroic dye according to claim 1, wherein m ¹ = m ² = m ³ = 1 and n ² = 1, and L ¹ and L ² are a divalent linking group not containing a cyclic structure and an azo bond. m ¹ = m ² = m ³ = 0, L ¹ is a group in which A ¹ and Ar ¹ are directly bonded or connected to each other, and L ² does not contain a cyclic structure and an azo bond. The dichroic dye according to claim 1, which is a divalent linking group. The dichroic dye according to any one of claims 1 to 3, wherein the B ¹ and B ² have an alkylene group, an alkenylene group, an alkynylene group, an ester group, an ether group, or a carbonyl group. 5. The dichroic dye according to claim 1, wherein the number of atoms of the B ² series part represented by the structural formula (I) is an even number. The dichroic dye according to any one of claims 1 to 5, which has any one of the following formulas (II) and (III) as a partial structure.

[In the formula (II),
X ⁴ represents an oxygen atom or —NR ¹⁰ — (R ¹⁰ is a hydrogen atom or a monovalent substituent);
R ⁸ represents a hydrogen atom or an alkyl group which may have a substituent,
B ⁴ represents a divalent linking group having 4 or more atoms in the series portion,
R ⁶ represents an alkyl group or an alkoxy group,
n ¹¹ and n ¹² each independently represents 0 or 1,
A ⁸ and A ⁹ each independently represents a 1,4-phenylene group which may have a substituent, or (E) -cyclohexane-1,4-diyl group which may have a substituent. Show.
In formula (III),
X ⁵ represents an oxygen atom, or —NR ¹¹ — (R ¹¹ represents a hydrogen atom or a monovalent substituent),
R ⁷ represents a hydrogen atom or an alkyl group which may have a substituent,
B ⁵ represents a divalent linking group having 4 or more atoms in the series portion,
R ⁹ represents an alkyl group or an alkoxy group,
n ¹³ and n ¹⁴ each independently represent 0 or 1,
A ¹⁰ and A ¹¹ each independently represents a 1,4-phenylene group which may have a substituent, or (E) -cyclohexane-1,4-diyl group which may have a substituent. Show. ]   A liquid crystal composition comprising the dichroic dye according to any one of claims 1 to 6.   A liquid crystal element comprising a liquid crystal phase containing the liquid crystal composition according to claim 7.

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