JP2022185493A - Dichroic dye composition, liquid crystal element, retardation plate, and polarizer - Google Patents

Abstract

To provide a novel dichroic dye composition useful for various optical elements, and an optical element using the same.SOLUTION: A dichroic dye composition comprises a squarylium pigment containing a heteroatom and a liquid crystal compound transmitting visible light.SELECTED DRAWING: None

Description

The present invention relates to a dichroic dye composition, a liquid crystal element, a retardation plate, a polarizer, and the like.

In liquid crystal display devices, polarizers are used to control optical rotation and birefringence in display, and in recent years, organic dyes have been studied as dichroic substances used in polarizers. For example, a polarizer using a guest-host type liquid crystal composition containing a host liquid crystal material and a guest dichroic dye has been proposed (Patent Documents 1 and 2).

Japanese Patent No. 5923941 Japanese Patent No. 6343866

However, Patent Documents 1 and 2 do not disclose the use of squarylium dyes as dichroic dyes.
An object of the present invention is to provide novel dichroic dye compositions useful for various optical elements such as polarizers, liquid crystal elements, retardation plates, polarizers and the like using the same.

The present invention relates to the following dichroic dye composition.
[1] A dichroic dye composition containing a squarylium dye containing a heteroatom and a liquid crystal compound that transmits visible light.

INDUSTRIAL APPLICABILITY According to the present invention, a novel dichroic dye composition useful for various optical elements such as liquid crystal elements, retardation plates and polarizers, and liquid crystal elements, retardation plates and polarizers using the same can be provided. .

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
In this specification, the compound represented by formula (A1) is referred to as compound (A1). The same applies to compounds represented by other formulas. The NIR dye composed of compound (A1) is also called NIR dye (A1), and the same applies to other dyes. Further, for example, the group represented by formula (1a) is also referred to as group (1a), and the groups represented by other formulas are the same.
In the present specification, the numerical range "to" includes upper and lower limits.

In this specification, unless otherwise specified, the alkyl group may be linear, branched, cyclic, or a combination of these structures.
Unless otherwise specified, the halogen atom includes fluorine, chlorine, bromine, iodine and the like, with fluorine being preferred.
In the present specification, unless otherwise specified, an aryl group refers to a group bonded via a carbon atom that constitutes an aromatic ring of an aromatic compound, such as a benzene ring, naphthalene ring, biphenyl, and the like. A heteroaryl group refers to a group bonded via a carbon atom or a heteroatom constituting an aromatic ring of an aromatic compound having a heteroatom, such as a furan ring, a thiophene ring, a pyrrole ring, and the like.

As used herein, a squarylium compound refers to a compound having a squarylium skeleton represented by the following formula (S1) that can have a resonance structure represented by the following formula (S2) in the structural formula. As used herein, the squarylium skeleton is represented by either formula (S1) or formula (S2).

<Dichroic dye composition>
The dichroic dye composition of the present invention (hereinafter also referred to as "the composition of the present invention") contains a heteroatom-containing squarylium dye and a liquid crystal compound that transmits visible light.
In the present invention, the squarylium dye functions as a dichroic dye. A dichroic dye means a dye having a property that the absorbance in the long axis direction and the absorbance in the short axis direction of the molecule are different. By including a dichroic dye in the composition of the present invention, the resulting optical element can function as a polarizer.
The squarylium dye is also a near-infrared absorbing dye that transmits visible light and has a maximum absorption wavelength in the wavelength region of 700 nm or longer. Since the dichroic dye is a near-infrared absorbing dye, an optical element capable of absorbing polarized light in the near-infrared and infrared regions can be obtained.

<Squarylium dye>
The squarylium dyes included in the compositions of the present invention contain heteroatoms. This increases the absorption coefficient and the visible light transmittance. Heteroatoms are distinguished from oxygen atoms in the squarylium skeleton. That is, the squarylium dye in the present invention contains a heteroatom in the structure other than the squarylium skeleton.
Heteroatoms include nitrogen, sulfur and oxygen atoms.

The squarylium dye is preferably a compound represented by the following formula (X).

The symbols in formula (X) are as follows.
Ar is an aromatic monocyclic, condensed or linked ring having 5 to 14 carbon atoms.
The carbon atoms constituting R ¹ and R ² , or at least one of R ¹ and R ² and Ar may be linked together to form a 3- to 10-membered heterocyclic ring together with the nitrogen atom.

When R ¹ and R ² do not form a heterocyclic ring, each of R ¹ and R ² may independently have a hydrogen atom or a substituent, an unsaturated bond between carbon atoms, a heteroatom or It represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a ring structure.
The monovalent hydrocarbon group may be branched, linear, or cyclic, but linear is preferred from the viewpoint that the squarylium dye is likely to be linear, ie, dichroic.
The monovalent hydrocarbon group preferably has 1 to 8 carbon atoms.

When R ¹ and R ² form a heterocyclic ring, each of R ¹ and R ² may independently have a substituent and contain an unsaturated bond between carbon atoms, a hetero atom or a ring structure. It represents a good divalent hydrocarbon group having 1 to 20 carbon atoms.

Substituents for R ¹ and R ² include halogen atom, hydroxyl group, carboxy group, sulfo group, cyano group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide groups, and alkoxy groups having 1 to 19 carbon atoms.
In addition, when R ¹ and R ² have a substituent, the number of carbon atoms of the substituent is included in the number of carbon atoms of R ¹ and R ² .

Substituents for R ¹ and R ² further include cyclic alkyl groups and aryl groups. The aryl group is preferably a phenyl group optionally having 1 to 5 substituents or a naphthyl group optionally having 1 to 7 substituents. Substituents which may substitute the hydrogen atoms of the phenyl group and naphthyl group include an alkyl group having 1 to 12 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon atoms, an alkoxy group, or an alkyl An amino group (wherein the alkyl group has 1 to 12 carbon atoms) can be mentioned. Phenyl and naphthyl groups are preferably unsubstituted or substituted with 1 to 3 hydrogen atoms, and preferred substituents include methyl, t-butyl, dimethylamino and methoxy groups.

The heteroatom for R ¹ and R ² is preferably an oxygen atom or a nitrogen atom.

When R ¹ and R ² contain an alicyclic ring or aromatic ring in the main chain or side chain, the alicyclic ring preferably has 3 to 10 carbon atoms. The number of carbon atoms in the aromatic ring is preferably 4-14.

From the viewpoint of improving the reliability of optical elements, the substituents for R ¹ and R ² are preferably polymerizable groups.

When R ¹ and R ² are linked together to form a heterocyclic ring together with a nitrogen atom, the number of members of the heterocyclic ring is 4 to 6 from the viewpoint that the squarylium dye is likely to be linear, that is, from the viewpoint that dichroism is likely to be exhibited. is preferred.
In such a heterocyclic ring, one of the hydrogen atoms bonded to the carbon atom farthest from the nitrogen atom may have an unsaturated bond or heteroatom between carbon atoms having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, and further Preferably, it may be substituted with 3 to 8 alkyl groups.
In such a heterocyclic ring, the carbon atom farthest from the nitrogen atom is replaced with a nitrogen atom, and the hydrogen atom bonded to the nitrogen atom may have an unsaturated bond or a heteroatom between carbon atoms. to 12, preferably 1 to 8, more preferably 3 to 8 alkyl groups may be substituted.
The alkyl group may be branched, straight-chain, or cyclic, but a straight-chain is preferable from the viewpoint that the squarylium dye readily exhibits dichroism. Also, some or all of the hydrogen atoms in the heterocyclic ring may be substituted with halogen atoms, in which case some or all of the hydrogen atoms bonded to carbon atoms not adjacent to the nitrogen atom are substituted with halogen atoms. preferably.

When at least one of R ¹ and R ² and the carbon atoms constituting Ar are linked to each other to form a heterocyclic ring together with the nitrogen atom, the heterocyclic ring preferably has 5 to 7 members. In such a heterocyclic ring, one of the hydrogen atoms bonded to the carbon atoms adjacent to the nitrogen atom may have an unsaturated bond or a heteroatom between the carbon atoms having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, and further preferably substituted with an alkyl group of 3 to 8, and some or all of the remaining hydrogen atoms are substituted with an alkyl group of 1 to 4 carbon atoms which may have an unsaturated bond or heteroatom between carbon atoms may be The alkyl group may be branched, straight-chain, or cyclic, but a straight-chain is preferable from the viewpoint that the squarylium dye readily exhibits dichroism. Also, some or all of the hydrogen atoms in the heterocyclic ring may be substituted with halogen atoms, in which case some or all of the hydrogen atoms bonded to carbon atoms not adjacent to the nitrogen atom are substituted with halogen atoms. preferably.

The two R ^1s may be different on the left and right sides of the squarylium skeleton, but it is preferable that the right and left sides are the same from the viewpoint of ease of production. The same applies to R ² and Ar. Moreover, the same applies to symbols after this. That is, the two symbols in the chemical formula may be different on the left and right sides of the squarylium skeleton, but from the viewpoint of ease of production, it is preferable that the left and right sides are the same.

Ar may have one or more substituents. Here, the substituent is a halogen atom, a hydroxyl group, or a substituent from the viewpoint that dichroism is easily expressed when the ratio of the molecular length in the short axis direction to the long axis direction (aspect ratio) of the squarylium dye is large. It is preferably selected from monovalent organic groups R ^Ar having 1 to 9 carbon atoms which may have The number of carbon atoms in R ^Ar and the number of carbon atoms in the substituent of R ^Ar are not included in the number of carbon atoms in Ar.
A halogen atom includes a chlorine atom, a fluorine atom, an iodine atom, and a bromine atom.
The monovalent organic group R ^Ar includes alkyl groups, alkoxy groups, acyloxy groups, araryl groups, amino groups, alkenyl groups, alkynyl groups, imino groups, cyano groups, carbonyl groups, aryl groups, heteroaryl groups and the like.
R ^Ar may have a substituent. The number of carbon atoms in the substituent is included in the number of carbon atoms in R ^Ar .

As the squarylium dye, compounds represented by any one of the following formulas (I) to (VI) are preferable. The squarylium dye may contain one or more compounds.

<Squarylium dye (I)>

However, the symbols in the above formula are as follows.

R ¹¹ and R ²¹ are each independently a hydrogen atom, an optionally substituted alkyl group or an alkoxy group having 1 to 20 carbon atoms which may contain an unsaturated bond or a hetero atom between carbon atoms; an acyloxy group having 1 to 19 carbon atoms, an aryl group having 6 to 11 carbon atoms, or an araryl group having 7 to 18 carbon atoms, optionally having a substituent and having an oxygen atom between the carbon atoms indicates The alkyl group is preferably linear from the viewpoint that the squarylium dye easily exhibits dichroism.

R ³¹ and R ⁵¹ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 8 carbon atoms, an acyloxy group having 1 to 8 carbon atoms, an aryl group having 6 to 9 carbon atoms, an araryl group having 7 to 9 carbon atoms which may have a substituent and which may have an oxygen atom between the carbon atoms, —NR ^31a R ^31b (R ^31a and R ^31b are each independently a hydrogen atom, Alkyl group having 1 to 4 carbon atoms, -C(=O)-R ^31c (R ^31c may have a hydrogen atom, a halogen atom, a hydroxyl group, a substituent, an unsaturated bond between carbon atoms, an oxygen atom , a hydrocarbon group having 1 to 8 carbon atoms which may contain a saturated or unsaturated ring structure), —NHR ^31d , or —SO ₂ —R ^31d (R ^31d has one or more hydrogen atoms each substituted with a halogen atom , a hydroxyl group, a carboxy group, a sulfo group, or a cyano group, and may contain an unsaturated bond between carbon atoms, an oxygen atom, a saturated or unsaturated ring structure, and a hydrocarbon group having 1 to 8 carbon atoms. ), or a group represented by formula (S) below (R ^31e and R ^31f independently represent a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 3 carbon atoms. k is 2 or 3.).

R ⁴¹ and R ⁶¹ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl or alkoxy group having 1 to 8 carbon atoms, an acyloxy group having 1 to 8 carbon atoms, an aryl group having 6 to 9 carbon atoms, Alternatively, it represents an araryl group having 7 to 9 carbon atoms which may have a substituent and which may have an oxygen atom between carbon atoms.

R ¹¹ and R ²¹ , R ¹¹ and R ⁴¹ , and R ²¹ and R ⁶¹ are each linked together with a nitrogen atom to form a 4- to 6-membered heterocyclic ring A1, a 5- to 7-membered heterocyclic ring B1, and A 5- to 7-membered heterocyclic ring C1 may be formed.

R ¹¹ and R ²¹ when heterocyclic ring A1 is formed represent an alkylene group having 3 to 5 carbon atoms or an alkyleneoxy group having 2 to 4 carbon atoms as the divalent group —Q ¹ — to which they are bonded. . Here, in the heterocyclic ring composed of a nitrogen atom and Q1, ^one of the hydrogen atoms bonded to the carbon atom farthest from the nitrogen atom may have an unsaturated bond or heteroatom between carbon atoms. It may be substituted with 1 to 12, preferably 1 to 8, more preferably 3 to 8 alkyl groups. The alkyl group is preferably linear from the viewpoint that the squarylium dye easily exhibits dichroism. Also, some or all of the hydrogen atoms in the heterocyclic ring may be substituted with halogen atoms, in which case some or all of the hydrogen atoms bonded to carbon atoms not adjacent to the nitrogen atom are substituted with halogen atoms. preferably.

R ¹¹ and R ⁴¹ when the heterocycle B1 is formed, and R ²¹ and R ⁶¹ when the heterocycle C1 is formed are the divalent groups —X ¹ —Y ¹ — and — As X ² -Y ² - (X ¹ and X ² are on the nitrogen-bonding side), X ¹ and X ² are groups represented by the following formula (1x) or (2x), and Y ¹ and Y ² are each A group represented by any one of the following formulas (1y) to (5y). When each of X ¹ and X ² is a group represented by the following formula (2x), each of Y ¹ and Y ² may be a single bond, in which case an oxygen atom may be present between the carbon atoms. .

In formula (1x), four Zs are each independently a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group, or -Nx ³⁸ x ³⁹ (x ³⁸ and x ³⁹ are each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms). x ³¹ to x ³⁶ each independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 10 carbon atoms, and x ³⁷ represents an alkyl group having 1 to 6 carbon atoms or an represents an aryl group.
R ^31a , R ^31b , R ^31c , x ³¹ to x ³⁷ , R ¹¹ when not forming a heterocyclic ring, R ²¹ , R ⁴¹ and R ⁶¹ are combined with any other of these to form 5 A membered ring or a 6-membered ring may be formed. x ³¹ and x ³⁶ and x ³¹ and x ³⁷ may be directly combined.

Substituents for R ¹¹ and R ²¹ include halogen atoms, hydroxyl groups, carboxy groups, sulfo groups, cyano groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N-substituted carbamoyl groups, An imide group and an alkoxy group having 1 to 19 carbon atoms can be mentioned.

Substituents for R ¹¹ and R ²¹ further include cyclic alkyl groups and aryl groups. The aryl group is preferably a phenyl group optionally having 1 to 5 substituents or a naphthyl group optionally having 1 to 7 substituents. Substituents which may substitute the hydrogen atoms of the phenyl group and naphthyl group include an alkyl group having 1 to 12 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon atoms, an alkoxy group, or an alkyl An amino group (wherein the alkyl group has 1 to 12 carbon atoms) can be mentioned. Phenyl and naphthyl groups are preferably unsubstituted or substituted with 1 to 3 hydrogen atoms, and preferred substituents include methyl, t-butyl, dimethylamino and methoxy groups.

When R ¹¹ and R ²¹ contain an alicyclic ring or aromatic ring in the main chain or side chain, the alicyclic ring preferably has 3 to 10 carbon atoms. The number of carbon atoms in the aromatic ring is preferably 4-14.

The substituents for R ¹¹ and R ²¹ are preferably polymerizable groups from the viewpoint of improving the reliability of optical elements.

Examples of compound (I) include compounds represented by any one of formulas (I-1) to (I-4).

The symbols in formulas (I-1) to (I-4) are the same as those defined in formula (I), and preferred embodiments are also the same unless otherwise specified.

In compound (I-1), X ¹ is preferably group (2x), and Y ¹ is preferably a single bond or group (1y). That is, as -Y ¹ -X ¹ -, -C(x ³¹ )(x ³² )-C(x ³³ )(x ³⁴ )- or -C(x ³⁵ )(x ³⁶ )-C(x ³¹ )(x ³² )-C(x ³³ )(x ³⁴ )- is preferred. In this case, x ³¹ , x ³² , x ³⁵ and x ³⁶ are each independently preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group. Each of x ³³ and x ³⁴ is independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 3 to 8 carbon atoms. One of x ³³ and x ³⁴ is a hydrogen atom, and the other is a linear chain having 3 to 8 carbon atoms, since dichroism is likely to occur when one linear alkyl group is bonded to the carbon atom adjacent to the nitrogen atom. Alkyl groups are particularly preferred.

As -Y ¹ -X ¹ -, specifically, divalent organic groups represented by the following formulas (11-1) to (11-4) and (12-1) to (12-3) are mentioned.
—C(CH ₃ ) ₂ —CH(CH ₃ )— (11-1)
—C(CH ₃ ) ₂ —CH ₂ — (11-2)
-C(CH ₃ ) ₂ -CH(nC _k H _2k+1 )- (11-3) (k = 2 to 6)
-C(CH ₃ ) ₂ -C(CH ₃ )(nC _k H _2k+1 )- (11-4) (k=3-6)
—C(CH ₃ ) ₂ —CH ₂ —CH ₂ — (12-1)
—C(CH ₃ ) ₂ —CH ₂ —CH(CH ₃ )— (12-2)
—C(CH ₃ ) ₂ —CH(CH ₃ )—CH ₂ — (12-3)

In compound (I-1), R ¹¹ is more preferably independently a methyl group from the viewpoint of improving the dichroic ratio.

In compound (I-4), R ⁵¹ is preferably a hydrogen atom or a hydroxyl group.

<Squarylium dye (II)>

However, the symbols in the above formula are as follows.
Each ring Z2 is independently a 5- or 6-membered ring having 0 to 3 heteroatoms in the ring, and the hydrogen atoms of ring Z2 may be substituted.
R ¹² and R ²² each independently contain a hydrogen atom, or an unsaturated bond between carbon atoms, a hetero atom, a saturated or unsaturated ring structure, and the number of carbon atoms that may have a substituent It represents a 1-20 monovalent hydrocarbon group.
R ³² and R ⁴² each independently represent a hydrogen atom, a halogen atom, or an optionally substituted alkyl or alkoxy group having 1 to 8 carbon atoms which may contain a heteroatom between carbon atoms; show.
The carbon atoms or heteroatoms constituting R ¹² and R ²² , R ¹² and R ⁴² , and R ²² and ring Z2 are linked together with a nitrogen atom to form a 4- to 6-membered heterocyclic ring A2 and a 5- to 5-membered heterocyclic ring A2. A 7-membered heterocyclic ring B2 and a 5- to 7-membered heterocyclic ring C2 may be formed, in which case the hydrogen atoms of the heterocyclic ring A2, the heterocyclic ring B2 and the heterocyclic ring C2 may be substituted.

Substituents for R ¹² and R ²² include halogen atoms, hydroxyl groups, carboxy groups, sulfo groups, cyano groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N-substituted carbamoyl groups, An imide group and an alkoxy group having 1 to 19 carbon atoms can be mentioned.

Substituents for R ¹² and R ²² further include cyclic alkyl or aryl groups. The aryl group is preferably a phenyl group optionally having 1 to 5 substituents or a naphthyl group optionally having 1 to 7 substituents. Substituents which may substitute the hydrogen atoms of the phenyl group and naphthyl group include an alkyl group having 1 to 12 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon atoms, an alkoxy group, or an alkyl An amino group (wherein the alkyl group has 1 to 12 carbon atoms) can be mentioned. Phenyl and naphthyl groups are preferably unsubstituted or substituted with 1 to 3 hydrogen atoms, and preferred substituents include methyl, t-butyl, dimethylamino and methoxy groups.

When R ¹² and R ²² contain an alicyclic or aromatic ring in the main chain or side chain, the alicyclic ring preferably has 3 to 10 carbon atoms. The number of carbon atoms in the aromatic ring is preferably 4-14.

The substituents for R ¹² and R ²² are preferably polymerizable groups from the viewpoint of improving the reliability of optical elements.

Examples of compound (II) include compounds represented by any one of formulas (II-1) to (II-3). From the viewpoint of durability, compounds represented by formula (II-1), formula Compounds represented by (II-3) are particularly preferred.

In formulas (II-1) and (II-2), each of R ¹² and R ²² may independently have a hydrogen atom or a substituent, and an unsaturated bond or heteroatom between carbon atoms. It represents an alkyl group having 1 to 20 carbon atoms which may be present. R ³² , R ⁴² , R ⁵² and R ⁶² each independently represent a hydrogen atom, a halogen atom, or an optionally substituted alkyl group having 1 to 8 carbon atoms. A halogen atom is mentioned as a substituent in an alkyl group.

In formula (II-3), R ¹² is a hydrogen atom or an optionally substituted alkyl group having 1 to 20 carbon atoms, optionally having an unsaturated bond or heteroatom between carbon atoms. indicates R ^92a to R ^92d are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 or more carbon atoms which may have a substituent and may have an unsaturated bond or heteroatom between carbon atoms and -CR ^92a R ^92b -CR ^92c R ^92d - has 20 or less carbon atoms. R ³² , R ⁷² and R ⁸² each independently represent a hydrogen atom, a halogen atom, or an optionally substituted alkyl group having 1 to 8 carbon atoms. A halogen atom is mentioned as a substituent in an alkyl group.

From the viewpoint of orientation, R ¹² and R ²² in compound (II-1) and compound (II-2) may independently have a substituent, and an unsaturated bond between carbon atoms or a heteroatom A linear alkyl group having 1 to 20 carbon atoms which may have is preferable, and a linear alkyl group having 1 to 3 carbon atoms is more preferable. Also, the carbon atoms constituting R ¹² and R ²² are preferably linked to form a heterocyclic ring, and the heterocyclic ring is particularly preferably a 4- to 6-membered ring.

From the viewpoint of orientation, R ¹² in compound (II-3) is preferably a straight-chain alkyl group having 1 to 8 carbon atoms, more preferably a straight-chain alkyl group having 1 to 4 carbon atoms, and is preferably a methyl group or an ethyl group. Especially preferred.

From the viewpoint of orientation, R ³² and R ⁴² are each preferably a hydrogen atom or a halogen atom, and particularly preferably a hydrogen atom.

R ⁷² and R ⁸² are each preferably a hydrogen atom, a halogen atom, or an optionally halogen-substituted alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom, a halogen atom, or a methyl group.

R ^92a is more preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 18 carbon atoms which may be substituted with a halogen atom and optionally have an unsaturated bond or heteroatom between carbon atoms. When one straight-chain alkyl group is bonded to the carbon atom adjacent to the nitrogen atom, dichroism is likely to occur, so R ^92a is a straight-chain alkyl group having 1 to 18 carbon atoms which may be substituted with a halogen atom. is particularly preferred.
R ^92b to R ^92d are each preferably a hydrogen atom, a halogen atom, or an optionally halogen-substituted alkyl group having 1 to 5 carbon atoms.
—CR ^92a R ^92b —CR ^92c R ^92d — includes divalent organic groups represented by the following groups (13-1) to (13-9).
—CH(CH ₃ )—C(CH ₃ ) ₂ — (13-1)
—C(CH ₃ ) ₂ —CH(CH ₃ )— (13-2)
—C(CH ₃ ) ₂ —CH ₂ — (13-3)
—C(CH ₃ ) ₂ —CH(C ₂ H ₅ )— (13-4)
—CH(CH ₃ )—C(CH ₃ )(CH ₂ —CH(CH ₃ ) ₂ )— (13-5)
—CH(CH ₂ CH(CH ₃ ) ₂ )—C(CH ₃ ) ₂ — (13-6)
—CH(C _n H _2n+1 )—C(CH ₃ ) ₂ − (13-7) (n=1 to 12)
—CH(C _n H _2n+1 )—CH ₂ − (13-8) (n=1 to 12)
—C(CH ₃ )(C _n H _2n+1 ) —C(CH ₃ ) ₂ − (13-9) (n=1 to 12)

More specific examples of compound (II-1) include the compounds shown in the table below. In addition, in the compounds shown in the following tables, the symbols on the left and right sides of the squarylium skeleton have the same meaning.

More specific examples of compound (II-3) include the compounds shown in the table below. In addition, in the compounds shown in the following tables, the symbols on the left and right sides of the squarylium skeleton have the same meaning.

Compounds (I) to (II) can be produced by known methods. Compound (I) can be produced by the methods described in US Pat. Compound (II) can be produced by the method described in International Publication No. 2017/135359.

<Squarylium dye (III)>

However, the symbols in the above formula are as follows.
R ¹³ and R ²³ each independently may have a substituent and may contain an unsaturated bond between carbon atoms, a hetero atom, an alicyclic ring or an aromatic ring having 1 to 20 carbon atoms. is an alkyl group.

R ¹³ may be combined with R ²³ , R ³³ , X ³¹ , X ³² or X ³³ to form a ring.
R ²³ may be linked with R ¹³ , R ³³ , X ³¹ , X ³² or X ³³ to form a ring.
The ring is preferably an alicyclic or aromatic ring having 3 to 6 members. Moreover, the ring may have a substituent.

Substituents for R ¹³ and R ²³ include halogen atoms, hydroxyl groups, carboxy groups, sulfo groups, cyano groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N-substituted carbamoyl groups, An imide group and an alkoxy group having 1 to 19 carbon atoms can be mentioned.

Substituents for R ¹³ and R ²³ further include cyclic alkyl groups and aryl groups. The aryl group is preferably a phenyl group optionally having 1 to 5 substituents or a naphthyl group optionally having 1 to 7 substituents. Substituents which may substitute the hydrogen atoms of the phenyl group and naphthyl group include an alkyl group having 1 to 12 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon atoms, an alkoxy group, or an alkyl An amino group (wherein the alkyl group has 1 to 12 carbon atoms) can be mentioned. Phenyl and naphthyl groups are preferably unsubstituted or substituted with 1 to 3 hydrogen atoms, and preferred substituents include methyl, t-butyl, dimethylamino and methoxy groups.

When R ¹³ and R ²³ contain an alicyclic or aromatic ring in the main chain or side chain, the alicyclic ring preferably has 3 to 10 carbon atoms. The number of carbon atoms in the aromatic ring is preferably 4-14.

The substituents for R ¹³ and R ²³ are preferably polymerizable groups from the viewpoint of improving the reliability of optical elements.

The carbon number of R ¹³ and R ²³ is 1-20. The number of carbon atoms of R ¹³ and R ²³ is preferably 2 to 20, more preferably 3 to 16, and even more preferably 4 to 12 when linear. The carbon number of R ¹³ and R ²³ is preferably 3 to 20, more preferably 4 to 16, and even more preferably 8 to 10 in the case of a branched chain.
When R ¹³ and R ²³ have a substituent, and when the main chain or side chain contains an alicyclic ring or an aromatic ring, the carbon number of the substituent, the alicyclic ring and the aromatic ring are included in the above number of carbon atoms.

R ¹³ and R ²³ may be the same or different, but are preferably the same from the standpoint of ease of production.

From the viewpoint of orientation, R ¹³ and R ²³ are preferably linear.

More preferably, R ¹³ and R ²³ are groups selected from groups (1b) to (5b) and groups (1c) to (2c).
—CH(C _n H _2n+1 ) ₂ (1b)
-C(C _n H _2n+1 ) ₃ (1c)
—CH ₂ —CH(C _n H _2n+1 ) ₂ (2b)
—CH ₂ —C(C _n H _2n+1 ) ₃ (2c)
—(CH ₂ ) ₂ —CH(C _n H _2n+1 ) ₂ (3b)
—(CH ₂ ) ₃ —CH(C _n H _2n+1 ) ₂ (4b)
—(CH ₂ ) _m —CH ₃ (5b)

However, in formulas (1b) to (4b) and formulas (1c) to (2c), n is an integer of 1 to 10, preferably 2 to 8, more preferably 2 to 4. However, the number of carbon atoms in groups (1b) to (4b) and groups (1c) to (2c) should be within the range of 1-20. Two C _n H 2n+1 in formulas (1b) to (4b) and three C _n H _{2n +1} in formulas (1c) to (2c) may each be linear or branched, They may be the same or different. In formula (5b), m is an integer of 0 to 19, preferably 1 to 19, more preferably 2 to 15, and even more preferably 3 to 11. Furthermore, groups (1b) to (5b) and groups (1c) to (2c) may have an oxygen atom between carbon atoms.

Further, when R ¹³ and R ²³ are linked to each other to form a heterocyclic ring together with a nitrogen atom, the divalent group -Q ³ - to which R ¹³ and R ²³ are linked is an alkylene group having 3 to 5 carbon atoms or a carbon represents an alkyleneoxy group of numbers 2 to 4; Here, in the heterocyclic ring composed of a nitrogen atom and ^Q3 , one of the hydrogen atoms bonded to the carbon atom farthest from the nitrogen atom may have an unsaturated bond or heteroatom between carbon atoms. It may be substituted with 1 to 12, preferably 1 to 8, more preferably 3 to 8 alkyl groups. The alkyl group is preferably linear from the viewpoint that the squarylium dye easily exhibits dichroism. Also, some or all of the hydrogen atoms in the heterocyclic ring may be substituted with halogen atoms, in which case some or all of the hydrogen atoms bonded to carbon atoms not adjacent to the nitrogen atom are substituted with halogen atoms. preferably.

R ³³ is an organic group R ^33A not essentially having an unsaturated bond or an organic group R ^33B essentially having an unsaturated bond.
The organic group R ^33A which does not necessarily have an unsaturated bond is a hydrogen atom, a halogen atom, a hydroxyl group, or an alkyl group which may have a substituent and which may contain an unsaturated bond or an oxygen atom between carbon-carbon atoms. , an alkoxy group, an aryl group or an araryl group.
The organic group R ^33B essentially having an unsaturated bond is an optionally substituted alkenyl group having 2 or more carbon atoms, an optionally substituted alkynyl group having 2 or more carbon atoms, and a substituted imino group having 1 or more carbon atoms, cyano group, organic group having 1 or more carbon atoms and optionally having a carbonyl structure and optionally having a substituent, aryl group having 6 to 9 carbon atoms and optionally having a substituent , or an optionally substituted heteroaryl group having 3 to 9 carbon atoms.
R ³³ may be linked with X ³¹ , X ³² or X ³³ to form a ring. As the ring, a ring having 5 to 7 members is preferable. Moreover, the ring may have a substituent.

Examples of substituents for R ^33A include halogen atoms, hydroxyl groups, carboxy groups, sulfo groups, cyano groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N-substituted carbamoyl groups, imide groups, An alkoxy group having 1 to 8 carbon atoms can be mentioned. When R ^33A is an aryl group or an araryl group, the substituent is a hydrogen atom bonded to an aromatic ring or a group that substitutes a hydrogen atom of an alkyl group thereof, and includes an aryl group in addition to the above substituents.

When R ^33A is an alkyl group or an alkoxy group, it preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms. When R ^33A is an aryl group, it preferably has 6 to 9 carbon atoms. When R ^33A is an araryl group, it preferably has 7 to 9 carbon atoms.
When R ^33A has a substituent, the carbon number of the substituent is included in the carbon number of R ^33A .

From the viewpoint of photostability, R ^33A is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, particularly preferably a hydrogen atom.

Substituents for the organic group R ^33B essentially having an unsaturated bond include a halogen atom, a hydroxyl group, a carbonyl structure-containing monovalent organic group, a phosphate group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide group, thiol group, sulfide group, alkoxy group having 1 to 8 carbon atoms, alkyl group having 1 to 8 carbon atoms, aryl group having 6 to 8 carbon atoms , a heteroaryl group having 3 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, a silyl group, and a halogenated alkyl group having 1 to 8 carbon atoms.
When R ^33B has a substituent, the carbon number of the substituent is included in the carbon number of R ^33B .

When R ^33B is an alkenyl group, it has 2 or more carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, still more preferably 2 to 4 carbon atoms.
As the alkenyl group, a group represented by the following formula (3-1) is preferable.

R ^3a , R ^3b , and R ^3c each independently represent a hydrogen atom, a halogen atom, a formyl group, a carboxy group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, an alkoxycarbonyl group, or a carbamoyl group. , N-substituted carbamoyl group, imide group, sulfide group, alkoxy group having 1 to 7 carbon atoms, alkyl group having 1 to 7 carbon atoms, aralkyl group having 6 to 7 carbon atoms, number of carbon atoms which may have a substituent 6 to 7 aryl group, optionally substituted heteroaryl group having 3 to 7 carbon atoms, alkenyl group optionally having 2 to 7 carbon atoms, optionally having substituent(s) Alkynyl groups having 2 to 7 carbon atoms, triorganosilyl groups having 3 to 7 carbon atoms (trimethylsilyl group, triphenylsilyl group, t-butyldiphenylsilyl group, etc.), trialkoxysilyl groups having 3 to 7 carbon atoms (trimethoxy silyl group, dimethoxyethoxysilyl group, etc.), or a halogenated alkyl group having 1 to 7 carbon atoms. R ^3b may combine with R ^3a or R ^3c to form a 3- to 6-membered ring which may contain a heteroatom, in which case the ring may have a substituent.

Examples of substituents in the ring formed by connecting an aryl group, a heteroaryl group, an alkenyl group, an alkynyl group, and ^R3b with ^R3a or ^R3c include a halogen atom, a formyl group, a carboxy group, a sulfo group, an amino group, N -substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, alkoxy group having 1 to 6 carbon atoms, alkyl group having 1 to 6 carbon atoms, 3 to 6 carbon atoms triorganosilyl group (trimethylsilyl group, etc.), C 3-6 trialkoxysilyl group (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or C 1-6 halogenated alkyl group.

Group (3-1) preferably includes the following structures.

When R ^33B is an alkynyl group, it has 2 or more carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, still more preferably 2 to 4 carbon atoms.
As the alkynyl group, a group represented by the following formula (3-2) is preferable.

R ^3d is hydrogen atom, halogen atom, formyl group, carboxy group, sulfo group, cyano group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, an alkoxy group having 1 to 7 carbon atoms, an alkyl group having 1 to 7 carbon atoms, an aralkyl group having 6 to 7 carbon atoms, an aryl group having 6 to 7 carbon atoms which may have a substituent, a substituent a heteroaryl group having 3 to 7 carbon atoms which may be substituted, an alkenyl group having 2 to 7 carbon atoms which may have a substituent, an alkynyl group having 2 to 7 carbon atoms which may have a substituent, a carbon number triorganosilyl groups of 3 to 7 (trimethylsilyl group, etc.), trialkoxysilyl groups of 3 to 7 carbon atoms (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or halogenated alkyl groups of 1 to 7 carbon atoms. .

Substituents in the aryl group, heteroaryl group, alkenyl group and alkynyl group include halogen atoms, formyl groups, carboxy groups, sulfo groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N -substituted carbamoyl group, imide group, sulfide group, alkoxy group having 1 to 5 carbon atoms, triorganosilyl group having 3 to 5 carbon atoms (trimethylsilyl group, etc.), trialkoxysilyl group having 3 to 5 carbon atoms (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or a halogenated alkyl group having 1 to 5 carbon atoms.

Group (3-2) preferably includes the following structures.

When R ^33B is an imino group, it has 1 or more carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms.
As the imino group, a group represented by the following formula (3-3) is preferable.

R ^3e and R ^3f each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a formyl group, a carboxy group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, alkoxy group having 1 to 8 carbon atoms, alkyl group having 1 to 8 carbon atoms, aralkyl group having 6 to 8 carbon atoms, optionally substituted 6 carbon atoms ~8 aryl group, optionally substituted C3-10 heteroaryl group, optionally substituted C2-8 alkenyl group, optionally substituted carbon alkynyl group having 2 to 8 carbon atoms, triorganosilyl group having 3 to 8 carbon atoms (trimethylsilyl group, etc.), trialkoxysilyl group having 3 to 8 carbon atoms (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or carbon It is a halogenated alkyl group of number 1-8. R ^3e and R ^3f may combine to form a 3- to 6-membered ring which may contain a heteroatom, in which case the ring may have a substituent.

Aryl group, heteroaryl group, alkenyl group, alkynyl group, and substituents in the ring formed by combining R ^3e and R ^3f include halogen atom, formyl group, carboxy group, sulfo group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, alkoxy group having 1 to 6 carbon atoms, alkyl group having 1 to 6 carbon atoms, triorgano having 3 to 6 carbon atoms A silyl group (trimethylsilyl group, etc.), a C3-6 trialkoxysilyl group (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or a C1-6 halogenated alkyl group can be mentioned.

Group (3-3) preferably includes the following structures.

When R ^33B is a cyano group, it is a group represented by the following formula (3-4).

When R ^33B is an organic group containing a carbonyl structure and having 1 or more carbon atoms and optionally having a substituent, the number of carbon atoms is 1 or more, preferably 1 to 8, more preferably 1 to 6, More preferably 1-4.
As such an organic group, a group represented by the following formula (3-5) is preferable.

R ^3g is a hydrogen atom, a hydroxyl group, a cyano group, an amino group, an N-substituted amino group, an alkoxycarbonyl group, a sulfide group, an alkoxy group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or 6 to 8 carbon atoms; aralkyl group, optionally substituted C6-8 aryl group, optionally substituted C3-8 heteroaryl group, optionally substituted C2 ~8 alkenyl groups, optionally substituted alkynyl groups having 2 to 8 carbon atoms, triorganosilyl groups having 3 to 8 carbon atoms (such as trimethylsilyl groups), trialkoxysilyl groups having 3 to 8 carbon atoms ( trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or a halogenated alkyl group having 1 to 8 carbon atoms.

Substituents in the aryl group, heteroaryl group, alkenyl group and alkynyl group include halogen atoms, formyl groups, carboxy groups, sulfo groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N -substituted carbamoyl group, imido group, sulfide group, alkoxy group having 1 to 6 carbon atoms, alkyl group having 1 to 6 carbon atoms, triorganosilyl group having 3 to 6 carbon atoms (trimethylsilyl group, etc.), 3 to 6 carbon atoms and a trialkoxysilyl group (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or a halogenated alkyl group having 1 to 6 carbon atoms.

Group (3-5) preferably includes the following structures.

When R ^33B is an aryl group, it has 6-9 carbon atoms.

As the aryl group, a group represented by the following formula (3-6) is preferable.

R ^3h , R ³ⁱ , R ^3j , R ^3k and R ^3l are each independently hydrogen atom, halogen atom, hydroxyl group, formyl group, carboxy group, sulfo group, cyano group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, alkoxy group having 1 to 3 carbon atoms, alkyl group having 1 to 3 carbon atoms, optionally substituted 2 carbon atoms to 3 alkenyl groups, optionally substituted alkynyl groups having 2 to 3 carbon atoms, trimethylsilyl groups, trimethoxysilyl groups, or halogenated alkyl groups having 1 to 3 carbon atoms.
R ^3h and R ³ⁱ , R ³ⁱ and R ^3j , R ^3j and R ^3k , R ^3k and R ^3l may be linked together to form a 3- to 6-membered ring which may contain a heteroatom.

Substituents for alkenyl and alkynyl groups include halogen atoms, formyl groups, carboxy groups, sulfo groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N-substituted carbamoyl groups, and imide groups. , a sulfide group, a methoxy group, a methyl group, or a halogenated methyl group.

Group (3-6) preferably includes the following structures.

When R ^33B is a heteroaryl group, it has 3-9 carbon atoms.

As the heteroaryl group, a group represented by any one of the following formulas (3-7) to (3-9) is preferable.

X ^3a , X ^3b , X ^3c , X ^3d and X ^3e are each independently N or CR ^3m and at least one is N; R ^3m is a hydrogen atom, a halogen atom, a hydroxyl group, a formyl group, a carboxy group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, an N-substituted carbamoyl group, an imide group; , a sulfide group, an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms, a phenyl group, a heteroaryl group having 3 to 6 carbon atoms which may have a substituent, optionally having a substituent C 2-6 alkenyl groups, optionally substituted C 2-6 alkynyl groups, C 3-6 triorganosilyl groups (such as trimethylsilyl groups), C 3-6 tri It is an alkoxysilyl group (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.) or a halogenated alkyl group having 1 to 6 carbon atoms.
When X ^3a , X ^3b , X ^3c , X ^3d and X ^3e are CR ^3m , adjacent X ^3a to X ^3e are 3- to 6-membered rings Ar ³⁰ and Ar ³¹ which may be linked to each other and may contain a heteroatom. , Ar ³² , Ar ³³ , in which case the ring may have a substituent.
Substituents in the heteroaryl group, alkenyl group, alkynyl group, ring Ar ³⁰ , Ar ³¹ , Ar ³² and Ar ³³ include halogen atom, formyl group, carboxy group, sulfo group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, trimethylsilyl group, alkoxy group having 1 to 4 carbon atoms, alkyl group having 1 to 4 carbon atoms, or halogen having 1 to 4 carbon atoms alkyl group.

Group (3-7) preferably includes the following structures.

X ^3f , X ^3g and X ^3h are each independently N or CR ³ⁿ . Y ^3a is S, O or NR ^3o .
R ³ⁿ and R ^3o each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a formyl group, a carboxy group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, alkoxy group having 1 to 6 carbon atoms, alkyl group having 1 to 6 carbon atoms, phenyl group, optionally substituted heteroaryl group having 3 to 6 carbon atoms , an alkenyl group having 2 to 6 carbon atoms which may have a substituent group, an alkynyl group having 2 to 6 carbon atoms which may have a substituent group, a triorganosilyl group having 3 to 6 carbon atoms (trimethylsilyl group, etc.) , a trialkoxysilyl group having 3 to 6 carbon atoms (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or a halogenated alkyl group having 1 to 6 carbon atoms.
When X ^3f , X ^3g and X ^3h are CR ³ⁿ and Y ^3a is NR ^3o , adjacent X ^3f , X ^3g , X ^3h and Y ^3a may be linked to each other and may contain a heteroatom. 6 rings Ar ³⁴ , Ar ³⁵ and Ar ³⁶ may be formed, in which case the rings may have a substituent.
Substituents in the heteroaryl group, alkenyl group, alkynyl group, ring Ar ³⁴ , Ar ³⁵ and Ar ³⁶ include halogen atom, formyl group, carboxy group, sulfo group, amino group, N-substituted amino group, nitro group and alkoxy group. carbonyl group, carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, trimethylsilyl group, alkoxy group having 1 to 4 carbon atoms, alkyl group having 1 to 4 carbon atoms, or halogenated alkyl group having 1 to 4 carbon atoms are mentioned.

Group (3-8) preferably includes the following structures.

X ³ⁱ , X ^3j and X ^3k are each independently N or CR ^3p . Y ^3b is S, O or NR ^3q . R ^3p and R ^3q each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a formyl group, a carboxy group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, alkoxy group having 1 to 6 carbon atoms, alkyl group having 1 to 6 carbon atoms, phenyl group, optionally substituted heteroaryl group having 3 to 6 carbon atoms , an alkenyl group having 2 to 6 carbon atoms which may have a substituent group, an alkynyl group having 2 to 6 carbon atoms which may have a substituent group, a triorganosilyl group having 3 to 6 carbon atoms (trimethylsilyl group, etc.) , a trialkoxysilyl group having 3 to 6 carbon atoms (trimethoxysilyl group, dimethoxyethoxysilyl group, etc.), or a halogenated alkyl group having 1 to 6 carbon atoms.
When X ³ⁱ , X ^3j , and X ^3k are CR ^3p and Y ^3b is NR ^3q , adjacent X ³ⁱ , X ^3j , X ^3k , and Y ^3b may be linked to each other and may contain a heteroatom. 6 rings Ar ³⁷ , Ar ³⁸ and Ar ³⁹ may be formed, in which case the rings may have a substituent.
Substituents in the aryl group, heteroaryl group, alkenyl group, alkynyl group, ring Ar ³⁷ , Ar ³⁸ and Ar ³⁹ include halogen atom, formyl group, carboxy group, sulfo group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide group, sulfide group, trimethylsilyl group, alkoxy group having 1 to 4 carbon atoms, alkyl group having 1 to 4 carbon atoms, or halogen having 1 to 4 carbon atoms alkyl group.

Group (3-9) preferably includes the following structures.

In formula (III), X ³¹ is CR ⁴³ or N. X ³² is S, NR ⁵³ , or O; ^X33 is S, ^NR63 , or O;

R ⁴³ is a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carbonyl structure-containing monovalent organic group, a phosphate group, a silyl group, a thiol group, a sulfide group, an amide structure-containing monovalent organic group, a sulfone amide group, urea group, urethane structure-containing monovalent organic group, optionally substituted C1-C9 alkyl group, optionally substituted C2-C9 alkenyl group, substituent an alkynyl group having 2 to 9 carbon atoms which may have a substituent, an aryl group having 6 to 9 carbon atoms which may have a substituent, a heteroaryl group having 3 to 9 carbon atoms which may have a substituent, an optionally substituted alkoxy group having 1 to 9 carbon atoms, an optionally substituted acyloxy group having 2 to 9 carbon atoms, or —N(R ^43g ) ₂ (R ^43g is a hydrogen atom or It is an optionally substituted alkyl group having 1 to 4 carbon atoms.).

When R ⁴³ is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an acyloxy group, or -N(R ^43g ) ₂ , R ⁴³ and any one of R ¹³ to R ³³ They may be linked to form a 3- to 6-membered ring. Moreover, the said ring may have a substituent.

Examples of substituents for R ⁴³ include a halogen atom, a hydroxyl group, a monovalent organic group containing a carbonyl structure, a phosphoric acid group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, N-substituted carbamoyl group, imido group, thiol group, sulfide group, alkoxy group having 1 to 8 carbon atoms, alkyl group having 1 to 8 carbon atoms, aryl group having 6 to 8 carbon atoms, heteroaryl group having 3 to 8 carbon atoms groups, alkenyl groups having 2 to 8 carbon atoms, alkynyl groups having 2 to 8 carbon atoms, silyl groups, and halogenated alkyl groups having 1 to 8 carbon atoms.
When R ⁴³ has a substituent, the carbon number of the substituent is included in the carbon number of R ⁴³ .

A fluorine atom is preferred as the halogen atom for R ⁴³ .

The carbonyl structure-containing monovalent organic group for R ⁴³ is preferably -C(=O)-R ^43a . R ^43a is a hydrogen atom, an optionally substituted C 1-8 alkyl group, or an optionally substituted C 1-8 alkoxy group, methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, isopropyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, methoxy group, ethoxy group, propoxy group, butoxy group, hexyloxy group, octyloxy group, isopropoxy group , isobutoxy group and 2-ethylhexyloxy group are preferred.

The silyl group for R ⁴³ is preferably —Si(R ^43b ) ₃ . R ^43b is a hydrogen atom or an optionally substituted alkyl group having 1 to 3 carbon atoms, preferably a methyl group, an ethyl group, a propyl group or an isopropyl group. The three R ^43b may be the same or different.

-SR ^43c is preferred as the sulfide group for R ⁴³ . R ^43c is a hydrogen atom or an optionally substituted alkyl group having 1 to 9 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, octyl, isopropyl, t-butyl The 2-ethylhexyl group is preferred.

As the amide structure-containing monovalent organic group for R ⁴³ , -C(=O)-NH-R ^43d is preferable. R ^43d is a hydrogen atom or an optionally substituted alkyl group having 1 to 8 carbon atoms, such as methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, isopropyl group, t-butyl The 2-ethylhexyl group is preferred.

The sulfonamide group for R ⁴³ is preferably —SO ₂ —N(R ^43e ) ₂ . R ^43e is a hydrogen atom or an optionally substituted alkyl group having 1 to 4 carbon atoms, preferably a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group or a t-butyl group. Two R ^43e may be the same or different.

The urethane structure-containing monovalent organic group for R ⁴³ is preferably -NH-C(=O) ^{OR 43f} . R ^43f is a hydrogen atom or an optionally substituted alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, octyl, isopropyl, t-butyl The 2-ethylhexyl group is preferred.

The alkyl group having 1 to 9 carbon atoms for R ⁴³ is preferably a methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, isopropyl group, isobutyl group, t-butyl group or 2-ethylhexyl group. .

The alkenyl group having 2 to 9 carbon atoms in R ⁴³ includes vinyl group, 1-propenyl group, isobutenyl group, styryl group, 2-fluorovinyl group, 2,2-difluorovinyl group, 3,3,3-trifluoro A propenyl group is preferred.

The alkynyl group having 2 to 9 carbon atoms for R ⁴³ is preferably an acetylenyl group, 1-propynyl group, trimethylsilylethynyl group, triethylsilylethynyl group, triisopropylsilylethynyl group, or t-butyldimethylsilylethynyl group.

The aryl group having 6 to 9 carbon atoms for R ⁴³ includes a phenyl group, 4-methoxyphenyl group, 3,4,5-trifluorophenyl group, 4-trifluoromethylphenyl group, 2,5-dimethylphenyl group, A 3-nitrophenyl group is preferred.

The heteroaryl group having 3 to 9 carbon atoms for R ⁴³ includes a pyridyl group, a pyrimidyl group, a quinolyl group, a furyl group, a thienyl group, an oxazolyl group, an imidazolyl group, a thiazolyl group, a benzoxazolyl group, a benzimidazolyl group, and a benzthiazolyl group. groups are preferred.

The alkoxy group having 1 to 9 carbon atoms for R ⁴³ is preferably methoxy, ethoxy, propoxy, butoxy, hexyloxy, octyloxy, isopropoxy, isobutoxy and 2-ethylhexyloxy.

The acyloxy group having 2 to 9 carbon atoms in R ⁴³ is preferably an acetoxy group, a propionyloxy group, a butyryloxy group, an isobutyryloxy group and a benzoyloxy group.

Two R ^43g in —N(R ^43g ) ₂ in R ⁴³ may be the same or different. Also, two R ^43g may be linked together to form a ring. —N(R ^43g ) ₂ is preferably a dimethylamino group, a diethylamino group, an ethylisopropylamino group, or a morpholino group.

X ³² is S, NR ⁵³ , or O;
R ⁵³ is a hydrogen atom, a monovalent organic group containing a carbonyl structure, a sulfo group, or an optionally substituted alkyl group having 1 to 9 carbon atoms, and is a hydrogen atom, a methyl group, an ethyl group, an isobutyl group, a 2 -ethylhexyl group, benzyl group, t-butoxycarbonyl group, benzyloxycarbonyl group, 9-fluorenylmethyloxycarbonyl group, allyloxycarbonyl group, 2,2,2-triethoxycarbonyl group, 2-nitrobenzenesulfonyl group preferable.
Substituents include the same substituents as those for R ⁴³ .

When R ⁵³ is an optionally substituted alkyl group having 1 to 9 carbon atoms, R ⁵³ may be linked to any one of R ¹³ to R ³³ to form a 3- to 6-membered ring.

^X33 is S, ^NR63 , or O;
R ⁶³ is a hydrogen atom, a monovalent organic group containing a carbonyl structure, a sulfo group, or an optionally substituted alkyl group having 1 to 9 carbon atoms, and is a hydrogen atom, a methyl group, an ethyl group, an isobutyl group, a 2 -ethylhexyl group, benzyl group, t-butoxycarbonyl group, benzyloxycarbonyl group, 9-fluorenylmethyloxycarbonyl group, allyloxycarbonyl group, 2,2,2-triethoxycarbonyl group, 2-nitrobenzenesulfonyl group preferable.
Substituents include the same substituents as those for R ⁴³ .

When R ⁶³ is an alkyl group, R ⁶³ may be linked with R ⁴³ to form a 3-6 membered ring.

In Formula (III), X ³¹ , X ³² and X ³³ include the following combinations.

From the viewpoint of ease of synthesis, preferred combinations are (X ³¹ , X ³² , X ³³ ) = (CR ⁴³ , S, S), (CR ⁴³ , S, O), (CR ⁴³ , O, S), ( CR ⁴³ , O, O), (CR ⁴³ , NR ⁵³ , S), (CR ⁴³ , NR ⁵³ , O), and a more preferred combination is (X ³¹ , X ³² , X ³³ )=(CR ⁴³ , S, S), ( ^CR43 , S, O), ( ^CR43 , ^NR53 , S), ( ^CR43 , ^NR53 , O).

As the squarylium compound represented by formula (III), the squarylium compound represented by formula (III-1) below and the squarylium compound represented by formula (III-2) below are selected from the standpoint of increasing molecular linearity in addition to ease of synthesis. A squarylium compound represented by is preferred.

R ¹³ , R ²³ , R ^33A , R ^33B and R ⁴³ are respectively the same as R ¹³ , R ²³ , R ^33A , R ^33B and R ⁴³ in Formula (III) including preferred embodiments.

More specific examples of compound (III-1) include the compounds shown in the table below. In addition, in the compounds shown in the following tables, the symbols on the left and right sides of the squarylium skeleton have the same meaning.

More specific examples of compound (III-2) include the compounds shown in the table below. In addition, in the compounds shown in the following tables, the symbols on the left and right sides of the squarylium skeleton have the same meaning.

The squarylium compound (III) can be synthesized by a known production method or a production method described below.

Squarylium compound (III-1) can be produced, for example, by the method described in WO2019/230570.

Scheme (FB) shows a method for obtaining a squarylium compound (III-B) in which R ³³ in the squarylium compound (III) is R ^33B .

Step A (step (A)) is a reaction for converting a carboxylic acid into a dialkylamine, and the details are shown in the scheme below.
HetAr in the following scheme means heteroaryl. Moreover, azide is preferably diphenylphosphoryl azide. _N alkylation is preferably an SN2 reaction using an alkyl halide and a base or a reductive amination reaction using an aldehyde and a reducing agent.

Step B (step (B)) is a reaction for converting halogen to various substituents, and includes cross-coupling reaction, Heck reaction, formylation, and Wittig reaction, Knevenagel reaction, Henry reaction, alkyl A nucleophilic addition reaction of a metal reactant or the like can be used, but is not limited thereto.

The starting material (a2-1) of scheme (FB) can be obtained, for example, from a known compound by the synthesis method described below.

A method for synthesizing a compound, wherein X ³¹ , X ³² and R in the starting material (a2-1) are as follows:
Compound (a2-1-1): (X ³¹ , X ³² , R)=(—CH, S, —CH ₂ CH ₃ )
Compound (a2-1-2): (X ³¹ , X ³² , R) = (-CH, S, H)
Compound (a2-1-3): (X ³¹ , X ³² , R)=(—CH, O, —CH ₂ CH ₃ )
Compound (a2-1-4): (X ³¹ , X ³² , R) = (-CH, O, H)

A method for synthesizing a compound, wherein X ³¹ , X ³² , (X ³³ ) and R in the starting material (a2-1) are as follows:
Compound (a2-1-5): (X ³¹ , X ³² , R)=(—CH, —NH, —CH ₂ CH ₃ )
Compound (a2-1-6): (X ³¹ , X ³² , R)=(—CH, —NH, H)
Compound (a2-1-7): (X ³¹ , X ³² , X ³³ , R)=(—CH, —NH, —NH, —CH ₂ CH ₃ )
Compound (a2-1-8): (X ³¹ , X ³² , X ³³ , R)=(—CH, —NH, —NH, H)

A method for synthesizing a compound, wherein X ³¹ , X ³² and R in the starting material (a2-1) are as follows:
Compound (a2-1-9): (X ³¹ , X ³² , R)=(N, O, —CH ₂ CH ₃ )
Compound (a2-1-10): (X ³¹ , X ³² , R)=(N, O, H)

A method for synthesizing a compound, wherein X ³¹ , X ³² and R in the starting material (a2-1) are as follows:
Compound (a2-1-11): (X ³¹ , X ³² , R)=(N, —NH, —CH ₂ CH ₃ )
Compound (a2-1-12): (X ³¹ , X ³² , R)=(N, —NH, H)

A method for synthesizing a compound, wherein X ³¹ , X ³² and R in the starting material (a2-1) are as follows:
Compound (a2-1-13): (X ³¹ , X ³² , R)=(N, S, —CH ₂ CH ₃ )
Compound (a2-1-14): (X ³¹ , X ³² , R) = (N, S, H)

<Squarylium dye (IV)>

However, the symbols in the above formula are as follows.
R ¹⁴ and R ²⁴ each independently may have a substituent and may contain an unsaturated bond between carbon atoms, a hetero atom, an alicyclic ring or an aromatic ring and has 1 to 20 carbon atoms. is an alkyl group.

R ¹⁴ may be combined with R ²⁴ , R ⁵⁴ or R ⁷⁴ to form a ring.
R ²⁴ may be combined with R ¹⁴ , R ⁵⁴ or R ⁷⁴ to form a ring.
The ring is preferably an alicyclic or aromatic ring having 3 to 6 members. Moreover, the ring may have a substituent.

The carbon number of R ¹⁴ and R ²⁴ is 1-20. The number of carbon atoms of R ¹⁴ and R ²⁴ is preferably 2 to 12, more preferably 3 to 10, and even more preferably 4 to 8 when linear. The carbon number of R ¹⁴ and R ²⁴ is preferably 3 to 12, more preferably 4 to 8, in the case of a branched chain.

Substituents for R ¹⁴ and R ²⁴ include the same substituents for R ¹³ and R ²³ in squarylium dye (III).

When R ¹⁴ and R ²⁴ contain an alicyclic or aromatic ring in the main chain or side chain, the alicyclic ring preferably has 3 to 10 carbon atoms. The number of carbon atoms in the aromatic ring is preferably 4-14.

When R ¹⁴ and R ²⁴ have a substituent, and when the main chain or side chain contains an alicyclic ring or an aromatic ring, the number of carbon atoms of the substituent, alicyclic ring and aromatic ring is included in the number of carbon atoms.

R ¹⁴ and R ²⁴ may be the same or different, but are preferably the same from the standpoint of ease of production.

From the viewpoint of orientation, R ¹⁴ and R ²⁴ are preferably linear.

More preferably, R ¹⁴ and R ²⁴ are groups selected from groups (1b) to (5b) and groups (1c) to (2c) for R ¹³ and R ²³ in the above squarylium dye (III).

Further, when R ¹⁴ and R ²⁴ are linked to each other to form a heterocyclic ring together with a nitrogen atom, the divalent group —Q ⁴ — to which R ¹⁴ and R ²⁴ are attached is the above-mentioned squarylium dye (III). Groups similar to the divalent group -Q ³ - are preferred.

R ³⁴ is an organic group R ^34A not essentially having an unsaturated bond or an organic group R ^34B essentially having an unsaturated bond.
The organic group R ^34A which does not necessarily have an unsaturated bond is a hydrogen atom, a halogen atom, a hydroxyl group, or an alkyl group which may have a substituent and which may contain an unsaturated bond or an oxygen atom between carbon-carbon atoms. , an alkoxy group, an aryl group or an araryl group.
The organic group R ^34B essentially having an unsaturated bond is an optionally substituted alkenyl group having 2 or more carbon atoms, an optionally substituted alkynyl group having 2 or more carbon atoms, and a substituted imino group having 1 or more carbon atoms, cyano group, organic group having 1 or more carbon atoms and optionally having a carbonyl structure and optionally having a substituent, aryl group having 6 to 9 carbon atoms and optionally having a substituent , or an optionally substituted heteroaryl group having 3 to 9 carbon atoms.

Examples of the substituent for R ^34A include the same substituents for R ^33A in the above-described squarylium dye (III).

When R ^34A is an alkyl group or an alkoxy group, the number of carbon atoms is preferably 1-8, more preferably 1-6, even more preferably 1-3. When R ^34A is an aryl group, it preferably has 6 to 9 carbon atoms. When R ^34A is an araryl group, it preferably has 7 to 9 carbon atoms.
When R ^34A has a substituent, the carbon number of the substituent is included in the carbon number of R ^34A .

R ^34A is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, particularly preferably a hydrogen atom, from the viewpoint of photostability.

Examples of the substituent for the organic group R ^34B essentially having an unsaturated bond include the same substituents for R ^33B in the above-mentioned squarylium dye (III).
When R ^34B has a substituent, the carbon number of the substituent is included in the carbon number of R ^34B .

When R ^34B is an alkenyl group, it has 2 or more carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, still more preferably 2 to 4 carbon atoms.
As the alkenyl group, a group represented by the above formula (3-1) is preferred, like R ^33B in the above squarylium dye (III).

When R ^34B is an alkynyl group, it has 2 or more carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, still more preferably 2 to 4 carbon atoms.
The alkynyl group is preferably a group represented by the above formula (3-2), like R ^33B in the above squarylium dye (III).

When R ^34B is an imino group, it has 1 or more carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms.
The imino group is preferably a group represented by the above formula (3-3), like R ^33B in the above squarylium dye (III).

When R ^34B is a cyano group, it is a group represented by the above formula (3-4), like R ^33B in the above squarylium dye (III).

When R ^34B is an organic group containing a carbonyl structure and having 1 or more carbon atoms and optionally having a substituent, the number of carbon atoms is 1 or more, preferably 1 to 8, more preferably 1 to 6, More preferably 1-4.
Such an organic group is preferably a group represented by the above formula (3-5), like R ^33B in the above squarylium dye (III).

When R ^34B is an aryl group, it has 6-9 carbon atoms.
The aryl group is preferably a group represented by the above formula (3-6), like R ^33B in the above squarylium dye (III).

When R ^34B is a heteroaryl group, it has 3 to 9 carbon atoms.
The heteroaryl group is preferably a group represented by any one of the above formulas (3-7) to (3-9), like R ^33B in the above squarylium dye (III).

R ⁴⁴ , R ⁵⁴ , R ⁶⁴ and R ⁷⁴ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, or a monovalent organic group having 1 to 9 carbon atoms.

A halogen atom includes a chlorine atom, a fluorine atom, an iodine atom, and a bromine atom.
Examples of monovalent organic groups include alkyl groups, alkoxy groups, acyloxy groups, araryl groups, amino groups, alkenyl groups, alkynyl groups, imino groups, cyano groups, carbonyl groups, aryl groups and heteroaryl groups.

In formula (IV), X ⁴¹ is CR ⁴³ or N. X ⁴² is S, NR ⁵³ , or O; X ⁴³ is S, NR ⁶³ , or O; R ⁴³ , R ⁵³ and R ⁶³ are the same as R ⁴³ , R ⁵³ and R ⁶³ in the above squarylium dye (III) including definitions and preferred embodiments.

More specific examples of compound (IV) include the compounds shown in the table below. In addition, in the compounds shown in the following tables, the symbols on the left and right sides of the squarylium skeleton have the same meaning.

Compound (IV) is a cup of 4-aminobenzeneboronic acid in which R ¹⁴ and R ²⁴ are bonded to the amino group, and a condensed heterocyclic compound in which a halogen atom is bonded to the carbon atom between X ⁴¹ and X ⁴² . It can be produced by linking by ring reaction and then reacting with squaric acid.

<Squarylium dye (V)>

However, the symbols in the above formula are as follows.
R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an optionally substituted alkyl group having 1 to 9 carbon atoms, an optionally substituted It is an aryl group having 4 to 9 carbon atoms or an araryl group having 5 to 9 carbon atoms which may have a substituent.

In R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ , the alkyl group, aryl group or araryl group may have a substituent.
Alkyl, aryl or araryl groups may also contain unsaturated bonds, oxygen atoms, ester bonds, amide bonds or thioamide bonds between carbon-carbon atoms.
Furthermore, the alkyl group, aryl group, or araryl group may have an oxygen atom, an ester bond, an amide bond, or a thioamide bond at the terminal bound to the thiophene ring.

Substituents for R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ include halogen atom, hydroxyl group, carboxy group, sulfo group, cyano group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, Examples include N-substituted carbamoyl groups, imide groups, and alkoxy groups having 1 to 8 carbon atoms. When R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ are an aryl group or an araryl group, the substituent is a hydrogen atom bonded to an aromatic ring or a group that substitutes a hydrogen atom of an alkyl group possessed by these, and the above substituent contains an aryl group in addition to

When R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ are alkyl groups, the number of carbon atoms is 1-8, preferably 1-4, more preferably 1-2.
When R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ are aryl groups, they have 4 to 9 carbon atoms, preferably 4 to 6 carbon atoms.
When R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ are araryl groups, they have 5 to 9 carbon atoms, preferably 5 to 7 carbon atoms.

When R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ have a substituent, the number of carbon atoms mentioned above includes the number of carbon atoms of the substituent.

R ³⁵ and R ⁴⁵ , R ⁴⁵ and R ⁵⁵ , and R ⁵⁵ and R ⁶⁵ may be linked to each other to form a monocyclic ring or a polycyclic ring in which 2 to 4 rings are condensed, in which case A hydrogen atom bonded to the ring may be substituted with a substituent.

The ring formed by connecting R ³⁵ and R ⁴⁵ and R ⁵⁵ and R ⁶⁵ may be an alicyclic ring or an aromatic ring, and may be a hydrocarbon ring or a heterocyclic ring. . An aromatic ring is preferred. A monocyclic ring includes a benzene ring, and a polycyclic ring includes a naphthalene ring, anthracene ring, phenanthrene ring, tetracene ring, chrysene ring and the like.

When R ⁴⁵ and R ⁵⁵ are linked, the dye (V) includes a structure in which a ring is formed between two thiophene rings and at least three rings are condensed.

A hydrogen atom bonded to a ring formed by connecting R ³⁵ and R ⁴⁵ , R ⁴⁵ and R ⁵⁵ , and R ⁵⁵ and R ⁶⁵ may be substituted with a substituent.
Substituents in these connecting rings include the same substituents as those in R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ , and optionally substituted phenyl groups.

R ¹⁵ and R ²⁵ are each independently an alkyl group having 1 to 20 carbon atoms or an araryl group having 4 to 20 carbon atoms.

R ¹⁵ and R ²⁵ may have substituents and may contain unsaturated bonds or heteroatoms between carbon atoms.
Substituents for R ¹⁵ and R ²⁵ include halogen atom, hydroxyl group, carboxy group, sulfo group, cyano group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group, N-substituted carbamoyl group, imide groups, and alkoxy groups having 1 to 19 carbon atoms.
In addition, when R ¹ and R ² have a substituent, the number of carbon atoms of the substituent is included in the number of carbon atoms of R ¹ and R ² .

Substituents for R ¹⁵ and R ²⁵ further include cyclic alkyl or aryl groups. The aryl group is preferably a phenyl group optionally having 1 to 5 substituents or a naphthyl group optionally having 1 to 7 substituents. Substituents which may substitute the hydrogen atoms of the phenyl group and naphthyl group include an alkyl group having 1 to 12 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon atoms, an alkoxy group, or an alkyl An amino group (wherein the alkyl group has 1 to 12 carbon atoms) can be mentioned. Phenyl and naphthyl groups are preferably unsubstituted or substituted with 1 to 3 hydrogen atoms, and preferred substituents include methyl, t-butyl, dimethylamino and methoxy groups.

When R ¹⁵ and R ²⁵ contain an alicyclic ring or an aromatic ring in the main chain or side chain, the alicyclic ring preferably has 3 to 10 carbon atoms. The number of carbon atoms in the aromatic ring is preferably 4-14.

The substituents for R ¹⁵ and R ²⁵ are preferably polymerizable groups from the viewpoint of improving the reliability of optical elements.

When R ¹⁵ and R ²⁵ are alkyl groups, the number of carbon atoms is 1-20, preferably 1-12, more preferably 1-10. R ¹⁵ and R ²⁵ are linear, branched or cyclic carbon atoms having 3 to 20 carbon atoms which may contain a heteroatom between carbon atoms, from the viewpoint of improving the visible light transmittance and the dichroic ratio. is preferred. The number of carbon atoms in the alkyl group is more preferably 3 to 12 when linear, more preferably 3 to 10 when branched, and more preferably 5 to 10 when cyclic. When R ¹⁵ and R ²⁵ have a substituent, the above carbon number includes the carbon number of the substituent.

R ¹⁵ and R ²⁵ are more preferably groups selected from groups (1a) to (15a), and particularly preferably group (3a).

R ¹⁵ and R ²⁵ may be linked to each other to form a 4- to 10-membered heterocyclic ring together with the nitrogen atom. is particularly preferably 4 to 6. In such a heterocyclic ring, one of the hydrogen atoms bonded to the carbon atom farthest from the nitrogen atom may have an unsaturated bond or heteroatom between carbon atoms having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, and further Preferably, it may be substituted with 3 to 8 alkyl groups. The alkyl group may be branched, straight-chain, or cyclic, but a straight-chain is preferable from the viewpoint that the squarylium dye readily exhibits dichroism. Also, some or all of the hydrogen atoms in the heterocyclic ring may be substituted with halogen atoms, in which case some or all of the hydrogen atoms bonded to carbon atoms not adjacent to the nitrogen atom are substituted with halogen atoms. preferably.

When the divalent group to which R ¹⁵ and R ²⁵ are bonded is represented by -Q ⁵ -, specific examples of -Q ⁵ - include the following groups (11) to (15).

—(CH ₂ ) ₄ — (11)
—(CH ₂ ) ₅ — (12)
—C(CH ₃ ) ₂ (CH ₂ ) ₂ C(CH ₃ ) ₂ — (13)
—C(CH ₃ ) ₂ (CH ₂ ) ₃ C(CH ₃ ) ₂ — (14)
—CH ₂ —CH(nC ₈ H ₁₇ )—(CH ₂ ) ₂ — (15)

As the squarylium compound (V), for example, a compound represented by the following formula (V-1) or a compound represented by the following formula (V-2) is preferable. The squarylium compound (V-1) is a squarylium compound (V) in which R ⁴⁵ and R ⁵⁵ are linked to form a cyclopentadithiophene ring. The squarylium compound (V-2) is a compound containing a structure in which R ⁴⁵ and R ⁵⁵ are not linked but two thiophene rings are linked in the squarylium compound (V).

The definitions of R ¹⁵ , R ²⁵ , R ³⁵ and R ⁶⁵ are the same as the definitions of R ¹⁵ , R ²⁵ , R ³⁵ and R ⁶⁵ in formula (V), including preferred embodiments.
The definitions of R ^45b and R ^55b are the same as those of R ⁴⁵ and R ⁵⁵ in Formula (V), including preferred embodiments, except that they are not linked to form a ring.

R ^45a and R ^55a are linear chains having 1 to 9 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon atoms, from the viewpoint of visible light transmittance, light resistance, and dichroic ratio improvement. Linear, branched or cyclic alkyl groups are preferred. The number of carbon atoms in the alkyl group is 1 to 9 when linear, preferably 3 to 9 when branched, and more preferably 5 to 9 when cyclic. R ^45a and R ^55a are more preferably, for example, a methyl group and a group selected from the groups (1a) to (13a) shown as specific examples of R ¹⁵ and R ²⁵ above, and are preferably a methyl group, a group (1a), or , group (3a) or group (9a) are particularly preferred.

R ^45a and R ^55a are preferably a phenyl group optionally having a substituent or a cyclic alkyl group having 5 to 9 carbon atoms from the viewpoint of heat resistance, light resistance and control of NIR absorption wavelength. Substituents for the phenyl group include an alkyl group having 1 to 3 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon atoms, an alkoxy group, or an alkylamino group (wherein the alkyl group has 1 to 3 carbon atoms). 3), and particularly preferred are a methyl group, a dimethylamino group, a methoxy group, and the like. The phenyl group is preferably unsubstituted or substituted with 1 to 3 hydrogen atoms.

Specific examples of the phenyl group which may have a substituent include groups (P1) to (P6).

More specific examples of compound (V-1) include the compounds shown in the table below. In addition, in the compounds shown in the following tables, the symbols on the left and right sides of the squarylium skeleton have the same meaning.

As the compound (V-1), among these, the compound (V-1-59) and the like are preferable from the viewpoint of improving the dichroic ratio.

Compound (V-2) more specifically includes the compounds shown in the table below. In addition, in the compounds shown in the following tables, the symbols on the left and right sides of the squarylium skeleton have the same meaning.

As the compound (V-2), among these, the compound (V-2-36) and the like are preferable from the viewpoint of improving the dichroic ratio.

Compound (V) can be produced by a known method, for example, by the method described in International Publication No. 2019/230660.

<Squarylium dye (VI)>

However, the symbols in the above formula are as follows.

R ¹⁶ and R ²⁶ each independently may have a substituent and may contain an unsaturated bond between carbon atoms, a hetero atom, an alicyclic ring or an aromatic ring and has 1 to 20 carbon atoms. is an alkyl group.

Substituents for R ¹⁶ and R ²⁶ include halogen atoms, hydroxyl groups, carboxy groups, sulfo groups, cyano groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N-substituted carbamoyl groups, An imide group and an alkoxy group having 1 to 19 carbon atoms can be mentioned.

Substituents for R ¹⁶ and R ²⁶ further include cyclic alkyl groups or aryl groups. As the aryl group, a phenyl group which may have a substituent or a naphthyl group which may have a substituent is preferable. Substituents which may substitute the hydrogen atoms of the phenyl group and naphthyl group include an alkyl group having 1 to 9 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon atoms, an alkoxy group, or an alkyl An amino group (wherein the alkyl group has 1 to 9 carbon atoms) can be mentioned. Phenyl and naphthyl groups are preferably unsubstituted or substituted with 1 to 3 hydrogen atoms, and preferred substituents include methyl, t-butyl, dimethylamino and methoxy groups.

The substituents for R ¹⁶ and R ²⁶ are preferably polymerizable groups from the viewpoint of improving the reliability of optical elements.

When R ¹⁶ and R ²⁶ contain an alicyclic or aromatic ring in the main chain or side chain, it is preferable in terms of heat resistance and control of NIR absorption wavelength. When R ¹⁶ and R ²⁶ do not have an alicyclic ring or an aromatic ring in the main chain or side chain, it is preferable from the viewpoint of light resistance, ease of production, and improvement in dichroic ratio. The number of carbon atoms in the alicyclic ring is preferably 3-10. The number of carbon atoms in the aromatic ring is preferably 4-14.

The carbon number of R ¹⁶ and R ²⁶ is 1-20. The carbon number of R ¹⁶ and R ²⁶ is preferably 2 to 20, more preferably 3 to 16, and even more preferably 4 to 12 when linear. The carbon number of R ¹⁶ and R ²⁶ is preferably 3 to 20, more preferably 4 to 16, and even more preferably 4 to 8 when branched.

When R ¹⁶ and R ²⁶ have a substituent, and when the main chain or side chain contains an alicyclic ring or an aromatic ring, the number of carbon atoms of the substituent, alicyclic ring and aromatic ring is included in the number of carbon atoms.

R ¹⁶ and R ²⁶ may be the same or different, but are preferably the same from the standpoint of ease of production. From the viewpoint of the degree of orientation, R ¹⁶ and R ²⁶ are preferably linear rather than branched, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 2 carbon atoms.

When R ¹⁶ and R ²⁶ are branched, the number of branches is not particularly limited. The number of branches is preferably 1-5, more preferably 1-3. From the viewpoints of both solubility in liquid crystals and solvents and ease of production, the branching position is preferably the β-position. In addition, one carbon atom may be branched into two or three.

R ¹⁶ and R ²⁶ are more preferably groups selected from, for example, groups (1b) to (5b), (1c), and (2c) described as more preferred embodiments of R ¹³ and R ²³ in the squarylium dye (III). .
—CH(C _n H _2n+1 ) ₂ (1b)
-C(C _n H _2n+1 ) ₃ (1c)
—CH ₂ —CH(C _n H _2n+1 ) ₂ (2b)
—CH ₂ —C(C _n H _2n+1 ) ₃ (2c)
—(CH ₂ ) ₂ —CH(C _n H _2n+1 ) ₂ (3b)
—(CH ₂ ) ₃ —CH(C _n H _2n+1 ) ₂ (4b)
—(CH ₂ ) _m —CH ₃ (5b)

However, in formulas (1b) to (4b), (1c) and (2c), n is an integer of 1 to 10, preferably 2 to 8, more preferably 2 to 4. However, the number of carbon atoms in groups (1b) to (4b) and groups (1c) to (2c) should be within the range of 1-20. Two C _n H 2n+1 in formulas (1b) to (4b), (1c), and (2c) and three C _n H _{2n +1} in formulas (1c) to (2c) may each be a straight chain. They may be branched and may be the same or different. In formula (5b), m is an integer of 0 to 19, preferably 1 to 19, more preferably 2 to 15, and even more preferably 3 to 11. In addition, groups (1b)-(5b), (1c), (2c) may have heteroatoms between carbon-carbon atoms.

R ³⁶ is a monovalent organic group having 9 or less carbon atoms containing an atom having a lone pair of electrons. The bonding of the group with the lone pair to the carbon atom closest to the squarylium skeleton increases the electron density of the unsaturated carbocycle, and the atom with the lone pair in the formation of the dye (reaction with squaric acid) becomes necessary. From this point of view, the atom having a lone pair of electrons in R ³⁶ is preferably directly bonded to the carbon atom of the unsaturated carbocyclic ring to which R ³⁶ is bonded.
Preferably, the atom with the lone pair of electrons is N, S or O.

R ³⁶ is preferably NH—Y ^36a —R ^36a , SH, or OH.
In NH-Y ^36a -R ^36a , Y ^36a is a single bond or a divalent organic group having 0 to 3 carbon atoms, preferably -CO-, -COO-, -CONH- or -SO ₂ -.
R ³⁶ is preferably NH--R ^36a , NH--CO--R ^36a , NH--COO--R ^36a , NH--CONH--R ^36a , NH--SO ₂ --R ^36a , SH or OH.

In NH-Y ^36a -R ^36a , R ^36a may have a substituent, may contain an unsaturated bond between carbon atoms, an oxygen atom, an alicyclic ring or an aromatic ring, and may have 1 to 9 carbon atoms. is an alkyl group. The upper limit of the total carbon number of Y ^36a and R ^36a is 9.

The number of carbon atoms in R ^36a is preferably 1 to 9, more preferably 1 to 4, and particularly preferably 1 to 2 when it is linear, and preferably 3 to 9 when it is branched, and 3 to 4 is particularly preferred.

Substituents for R ^36a include the same groups as the substituents for R ¹⁶ and R ²⁶ .
When R ^36a has a substituent and when the main chain or side chain contains an alicyclic ring or an aromatic ring, the number of carbon atoms in the substituent, the alicyclic ring and the aromatic ring are included in the above number of carbon atoms.

From the viewpoint of improving the dichroic ratio, R ^36a is preferably linear.

R ^36a is more preferably a group selected from groups (11b) to (15b), (11c) and (12c).
—CH(C _n H _2n+1 ) ₂ (11b)
-C(C _l H _2l+1 ) ₃ (11c)
—CH ₂ —CH(C _n H _2n+1 ) ₂ (12b)
—CH ₂ —C(C _l H _2l+1 ) ₃ (12c)
—(CH ₂ ) ₂ —CH(C _n H _2n+1 ) ₂ (13b)
—(CH ₂ ) ₃ —CH(C _n H _2n+1 ) ₂ (14b)
—(CH ₂ ) _m —CH ₃ (15b)

However, in formulas (11b) to (14b), n is an integer of 1 to 3, preferably 2 to 3. In formulas (11c) and (12c), l is an integer of 1-2. Two C _n H _2n+1 or three C _l H _2l+1 in formulas (11b)-(14b), (11c), (12c) may be linear or branched and may be identical. may be different. In formula (15b), m is an integer of 0 to 8, preferably 0 to 8, more preferably 0 to 3, and even more preferably 0 to 1. Furthermore, groups (11b)-(15b), (11c) and (12c) may have an oxygen atom between carbon atoms.

R ⁴⁶ is a hydrogen atom or an alkyl group having 1 to 9 carbon atoms.

The number of carbon atoms in the alkyl group is preferably 1-8, more preferably 1-4.
The alkyl group may be linear or branched, but is preferably linear from the viewpoint of improving the dichroic ratio.

When R ⁴⁶ is an alkyl group having 1 to 9 carbon atoms, a group selected from groups (11b) to (15b), (11c) and (12c) described as preferred embodiments for R ^36a is more preferred.

From the viewpoint of steric hindrance, R ⁴⁶ is preferably a hydrogen atom.

R ⁵⁶ is a hydrogen atom or an alkyl group having 1 to 9 carbon atoms.
From the viewpoint of steric hindrance, R ⁵⁶ is preferably a hydrogen atom.

R ¹⁶ and R ²⁶ , R ¹⁶ and R ⁴⁶ , R ³⁶ and R ⁴⁶ may be linked together to form a ring.
As the ring, R ¹⁶ and R ²⁶ , R ¹⁶ and R ⁴⁶ are preferably 3- to 6-membered alicyclic rings, and R ³⁶ and R ⁴⁶ are preferably 3- to 6-membered alicyclic or aromatic rings. Moreover, the ring may have a substituent. Substituents include the same groups as the substituents for R ¹⁶ and R ²⁶ .

X ⁶¹ is C=O, C ₌ S, or SO2.

As the squarylium compound (VI), a squarylium compound represented by the following formula (VI-1) is preferable.

R ¹⁶ to R ⁴⁶ are the same as R ¹⁶ to R ⁴⁶ in formula (VI) including preferred embodiments.

The squarylium compound (VI) includes the following squarylium compound (VI-11) in which R ³⁶ is NH—CO—R ^36a , and the following squarylium compound (VI-12) in which R ³⁶ is NH—SO ₂ —R ^36a . , the squarylium compound (VI-13) below, wherein R ³⁶ is NH-CONH-R ^36a , the squarylium compound (VI-14) below, wherein R ³⁶ is NH-COO-R ^36a , R ³⁶ is OH, The following squarylium compound (VI-15) is preferred.

As the squarylium compounds (VI-11) to (VI-15), more specifically, R ¹⁶ , R ²⁶ , R ^36a , and R ⁴⁶ are compounds shown in the following table (in the table, the squarylium compounds (VI-11) to (VI-15) are also shown together.). In the table, R ¹⁶ , R ²⁶ , R ^36a and R ⁴⁶ represent the symbols of the formulas when they are the groups having the formulas. In all the compounds shown in the table, R ¹⁶ , R ²⁶ , R ^36a and R ⁴⁶ are all the same on the left and right sides of the formula.

<Method for producing compound (VI)>
The method for producing the squarylium compound (VI) will be described using the method for producing the squarylium compound (VI-11), but the method for producing the squarylium compound (VI) is not limited thereto.
Scheme (F-A11) shows a method for obtaining squarylium compound (VI-11).

_{( 1} ) _{Compound ( pA11} -2) is obtained.
(2) A compound (pA11-3) is obtained by a nitration reaction.
(3) A compound (pA11-4) is obtained by deprotecting the amino group.
(4) N alkylation (S _N 2 reaction using alkyl halide and base, or reductive amination reaction using aldehyde and reducing agent) to give compound (pA11-5).
(5) Reduction of the nitro group gives compound (pA11-6).
(6) Compound (pA11-7) is obtained by reacting compound (pA11-6) with an alkanoyl chloride (R ^36a -C(=O)-Cl).
(7) A compound (pA11-8) is obtained by deprotecting the methoxy group.
(8) Compound (VI-11) is obtained by reacting compound (pA11-8) with squaric acid.

The squarylium compound (VI-12) can be produced by changing the alkanoyl chloride (R ^36a -C(=O)-Cl) in step (6) above to R ^36a SO ₂ Cl.
The squarylium compound (VI-13) can be produced by reacting R ^36a NH ₂ after reacting carbonyldiimidazole in step (6) above.
The squarylium compound (VI-14) can be produced by changing the alkanoyl chloride (R ^36a -C(=O)-Cl) in step (6) above to R ^36a OC(=O)-Cl.

The content of the squarylium dye in the dichroic dye composition of the present invention is preferably 0.1 mmol or more, more preferably 0.3 mmol or more, relative to 100 parts by mass of the liquid crystal compound, from the viewpoint of obtaining sufficient absorbance. In addition, from the viewpoint of developing a stable liquid crystal phase over a wide temperature range, it is preferably 10 mmol or less, more preferably 5 mmol or less per 100 parts by mass of the liquid crystal compound. Two or more kinds of dyes may be used in combination, and in such a case, the total content should be within the above range.

<Liquid crystal compound>
The dichroic dye composition of the present invention contains, in addition to the above dyes, a liquid crystal compound that transmits visible light.

Examples of types of liquid crystal compounds include non-polymerizable liquid crystal compounds exhibiting a nematic phase, polymerizable liquid crystal compounds exhibiting a nematic phase, and polymerizable liquid crystal compounds exhibiting a smectic phase. The liquid crystal compound may be synthesized by a known manufacturing method, or a commercially available product may be used.

The content of the liquid crystal compound in the dichroic dye composition of the present invention is preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass from the viewpoint of expressing a stable liquid crystal phase over a wide temperature range. % or more, and preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and particularly preferably 99% by mass or less from the viewpoint of sufficient absorbance.

<Other ingredients>
A compound that does not exhibit liquid crystallinity is added to the dichroic dye composition of the present invention for the purpose of changing the physical properties of the host liquid crystal to a desired range (for example, adjusting the temperature range of the liquid crystal phase to a desired range). You may Further, compounds such as chiral compounds, ultraviolet absorbers, antioxidants and polymerization initiators may be contained. Examples of such additives include chiral agents for TN and STN described on pages 199 to 202 of "Liquid Crystal Device Handbook" (edited by the Japan Society for the Promotion of Science, 142nd Committee, Nikkan Kogyo Shimbun, 1989). be done.
The dichroic dye composition of the present invention may contain an optically active compound, such as cholesteryl nonanoate, which may or may not exhibit a liquid crystal phase, and may contain various additives such as ultraviolet absorbers and antioxidants. It may contain an agent.

Further, when the liquid crystal compound is a non-polymerizable liquid crystal compound exhibiting a nematic phase, the dichroic dye composition of the present invention may contain a liquid crystalline curable compound having a polymerizable functional group or a non-liquid crystalline compound having a polymerizable functional group. A curable compound may be added. From the viewpoint of producing a polymer dispersed liquid crystal device (PDLC) having a high-quality transmission-scattering operation mode, in the dichroic dye composition, the non-liquid crystal content is higher than the content of the liquid crystalline curable compound. Preferably, the content of the liquid curable compound is large, and the total amount of the liquid crystalline curable compound and the non-liquid crystalline curable compound is 8% by mass or more and less than 20% by mass of the total.

In addition, the PDLC shows a scattering state when no voltage is applied, but also includes an element that shows a transmission state when no voltage is applied. Elements that exhibit a transmissive state when no voltage is applied include a structure composed of a curable compound having the same orientation as the liquid crystal molecules in the composition, and the liquid crystal molecules take the same alignment axis as the structure. Transmittance is secured by taking the orientation as follows. In the present invention, the curable compound includes both those having liquid crystallinity and those having no liquid crystallinity, and the content of the curable compound is 5% by mass or more and less than 20% by mass of the entire composition. is preferred.

<Refractive index anisotropic film, light absorption anisotropic film>
Since the squarylium dye, which is a dichroic dye in the present invention, transmits visible light and absorbs near-infrared light, the film formed from the dichroic dye composition of the present invention has refractive index anisotropy and light absorption. It has both properties of anisotropy. Therefore, it functions as a retardation film in the visible light region and as a polarizing film in the near-infrared region. A retardation film is used to convert linearly polarized light into circularly polarized light or elliptically polarized light, or conversely, to convert circularly polarized light or elliptically polarized light into linearly polarized light.
Also, the polarizing film decomposes incident unpolarized light into two orthogonal polarization components, one polarization component. It is used to transmit one polarization component and absorb the other polarization component. The axial direction of the polarized component to be transmitted is called the transmission axis, and the axial direction of the polarized component to be absorbed is called the absorption axis.

<Optical element>
The dichroic dye composition of the present invention having both liquid crystallinity and dichroism is useful as a material for various optical elements such as retardation plates, polarizers and liquid crystal elements. Since the dichroic dye in the present invention has the property of absorbing near-infrared light, it is possible to prepare a visible light retardation film that absorbs near-infrared light and a near-infrared light absorbing polarizing film that transmits visible light. is.
Each optical element will be described below.

<Phase difference plate, polarizer>
The present invention also relates to a retardation plate having a substrate and the refractive index anisotropic film of the present invention on the substrate or between the pair of substrates.
The present invention also relates to a polarizer comprising a substrate and the light absorption anisotropic film of the present invention on the substrate or between the pair of substrates.
As the substrate, a substrate generally made of glass or plastic can be used. Examples of plastic substrates include acrylic resins, polycarbonate resins, and epoxy resins. As for the substrate, for example, those described in "Liquid Crystal Device Handbook" (edited by the Japan Society for the Promotion of Science, 142nd Committee, Nikkan Kogyo Shimbun, 1989), pp. 218-231 can be used.

It is preferable to form an alignment-treated layer (orientation film) on the surface of the substrate in contact with the refractive index anisotropic film or the light absorption anisotropic film. The alignment treatment includes, for example, a method of applying a quaternary ammonium salt for orientation, a method of applying polyimide and orientation by rubbing, a method of obliquely evaporating SiOx for orientation, and further, using photoisomerization. and an orientation method by light irradiation. As for the alignment film, for example, those described in "Liquid Crystal Device Handbook" (edited by Japan Society for the Promotion of Science, 142nd Committee, Nikkan Kogyo Shimbun, 1989), pp. 240-256 are used.

When a refractive index anisotropic film or a light absorption anisotropic film is formed between a pair of substrates, for example, the pair of substrates are opposed to each other with a spacing of 1 to 50 μm via a spacer or the like, and the film is formed between the substrates. and a method of injecting the dichroic dye composition of the present invention into the space, and if necessary, irradiating light of a predetermined wavelength to perform photopolymerization. As the spacer, for example, those described in "Liquid Crystal Device Handbook" (edited by the Japan Society for the Promotion of Science, 142nd Committee, Nikkan Kogyo Shimbun, 1989), pp. 257-262 can be used.

<Liquid crystal element>
The present invention also relates to a liquid crystal element comprising a pair of electrode substrates and a liquid crystalline layer formed between the electrode substrates. The liquid crystalline layer is formed from the dichroic dye composition of the present invention. The electrode layer formed on the substrate is preferably a transparent electrode layer, and can be formed of, for example, indium oxide, indium tin oxide (ITO), tin oxide, or the like. As for the transparent electrode, for example, those described in "Liquid Crystal Device Handbook" (edited by the Japan Society for the Promotion of Science, 142nd Committee, Nikkan Kogyo Shimbun, 1989), pp. 232-239 are used.
The liquid crystal element of the present invention also functions as a retardation plate in the visible light region, and also functions as a polarizer in the near-infrared region.

The optical element of the present invention can be mounted on various devices described below.

<Imaging device>
An imaging device of the present invention includes, for example, a solid-state imaging device, an imaging lens, and the optical element of the present invention. As a result, a good image with high color reproducibility can be obtained.

<Light wave ranging device>
A light wave distance measuring device of the present invention includes, for example, a laser diode, a scanning unit such as a beam splitter or a MEMS mirror, a photodiode, and the optical element of the present invention. As a result, it is possible to suppress return optical noise to the laser diode and stray light in the light wave rangefinder, improve detection accuracy, and reduce erroneous detection.

<Solar control member>
The solar radiation control member of the present invention includes, for example, the optical element of the present invention. Thereby, transmission and absorption of near-infrared light can be switched without impairing the transmittance of visible light.

<Virtual reality device>
The virtual reality apparatus of the present invention includes, for example, a display unit such as an LCD, OLED, or μLED, a lens unit, an optical element of the present invention between the display unit and the lens unit, and a near-infrared illuminator capable of photographing the user's eyes. and a camera equipped with
The lens unit can include a retardation plate and a reflective polarizer, and the retardation plate of the present invention can be used as the retardation plate.
As an optical element between the display unit and the lens unit, the retardation plate and polarizer of the present invention can be used.
With the above configuration, it is possible to suppress stray near-infrared light in the virtual reality apparatus, improve eye tracking accuracy, and reduce erroneous detection.

EXAMPLES Next, the present invention will be described in more detail with reference to examples.

The dyes used in each example are as follows.
Compounds 1-4: Synthesized based on WO2017/135359.
Compound 5: Pyrrolidone and TMS-Cl are reacted to give N-TMS-pyrrolidone, LDA is reacted with n-octane iodide, water is added to give 5-octylpyrrolidone, and reduction with LiAlH ₄ is performed. , the corresponding amine (3-octylpyrrolidine) was synthesized, and others were synthesized based on WO2017/135359.
Compounds 6-7: Synthesized based on WO2017/135359.
Compound 8: Synthesized based on WO2019/230570.

Compound 9: Synthesized according to the reaction route shown below.

<Step 1>
Lithium diisopropylamide (THF/hexane solution, 1.08 M, 200 mL, 216 mmol) was placed in a nitrogen-substituted 1 L four-necked flask, cooled to −−78° C., and diluted with THF (200 mL). Dibromothiophene (50.11 g, 207 mmol) was added via dropping funnel over 10 minutes and then stirred for 30 minutes. After raising the temperature to 0° C. and stirring for 10 minutes, DMF (19.2 mL, 248 mmol) was added and the mixture was stirred at 30° C. for 2.5 hours. After completion of the reaction, the mixture was cooled to 0° C. and saturated aqueous ammonium chloride (200 mL) was added. The extract was extracted with ethyl acetate, washed with saturated brine, dried over magnesium sulfate and concentrated under reduced pressure to give a crude intermediate a1-1 (60.8 g). The crude product was used for the next reaction.
¹ H NMR (CDCl ₃ , 300 MHz) δ 9.95 (1 H, s), 7.76 (1 H, s).

<Step 2>
Potassium carbonate (42.86 g, 310 mmol), the crude product of intermediate a1-1 (60.82 g), DMF (200 mL), ethyl mercaptoacetate (25 mL, 229 mmol), and 18-crown-6-ether (2.742 g, 10.4 mmol) was added, and the mixture was heated and stirred at 60° C. overnight. After cooling to room temperature, solids were removed by filtration, water was added and extracted with ethyl acetate, washed with saturated brine, dried over magnesium sulfate, concentrated under reduced pressure, washed with hexane, and intermediate a1-2 (42.6 g, 2 step 71% yield).
¹ H NMR (CDCl ₃ , 300 MHz) δ 8.01 (1 H, s), 7.47 (1 H, s), 4.39 (2 H, q, J = 7.1 Hz), 1.40 (3 H, t, J=7.2 Hz).

<Step 3>
Intermediate a1-2 (29.31 g, 100.6 mmol), potassium vinyltrifluoroborate (15.52 g, 110.1 mmol), palladium chloride (II) (374.6 mg, 2 .007 mmol), triphenylphosphine (1.571 g, 5.990 mmol), cesium carbonate (97.72 g, 299.9 mmol), and THF/water (9/1) (200 mL) were added, and the mixture was heated and stirred at 85°C for 3 days. did. After completion of the reaction, water was added and the mixture was extracted with dichloromethane, washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure to obtain a crude intermediate a1-3 (27.09 g). The crude product was used in the next reaction as is.
¹ H NMR (CDCl ₃ , 300 MHz) δ 8.00 (1 H, s), 7.47 (1 H, s), 6.83 (1 H, dd, J = 17.7, 11.0 Hz), 5.73 ( 1H, d, J = 17.6 Hz), 5.48 (1 H, d, J = 10.9 Hz), 4.40 (2H, q, J = 7.1 Hz), 1.41 (3H, t, J = 7.1 Hz).

<Step 4>
A nitrogen-substituted eggplant flask (300 mL) was charged with the above crude product, lithium hydroxide monohydrate (4.617 g, 110.0 mmol), tetrabutylammonium iodide (1.848 g, 5.003 mmol), and water (33 mL). , methanol (20 mL) and THF (67 mL) were added, and the mixture was heated and stirred at 80° C. for 3 hours. After completion of the reaction, hexane was added and the mixture was extracted with water and then acidified with 6N hydrochloric acid. The extract was extracted with ethyl acetate, dried over magnesium sulfate, concentrated under reduced pressure, and washed with dichloromethane to obtain intermediate a1-4 (18.69 g, 88% yield over two steps).
¹ H NMR (DMSO-d ₆ , 300 MHz) δ 8.04 (1 H, s), 7.72 (1 H, s), 6.91 (1 H, dd, J=17.6, 11.1 Hz), 5. 69 (1H,d,J=17.8Hz), 5.47 (1H,d,J=11.1Hz).

<Step 5>
Intermediate a1-4 (7.489 g, 35.61 mmol), diphenylphosphoryl azide (11.3 mL, 52.0 mmol), triethylamine (7.3 mL, 52 mmol), THF ( 140 mL) was added, and the mixture was heated under reflux at 80° C. for 2.5 hours. After allowing to cool to room temperature, silica gel (500 cm ³ ) was added, filtered, concentrated under reduced pressure, and subjected to silica gel column chromatography (hexane:ethyl acetate=95:5) to obtain intermediate a1-5 (6.938 g, 94% yield). got
¹ H NMR (CDCl ₃ , 300 MHz) δ 8.04 (1 H, s), 7.55 (1 H, s), 6.83 (1 H, dd, J = 17.8, 11.1 Hz), 5.73 ( 1H, d, J = 17.6 Hz), 5.51 (1 H, d, J = 11.1 Hz).

<Step 6>
Intermediate a1-5 (724.4 mg, 3.495 mmol), THF (8.0 mL), and water (8.0 mL) were added to a nitrogen-substituted microwave test tube, and subjected to microwave irradiation at 150 ° C. for 5 minutes. It was heated and stirred. This was carried out in 7 batches, and a total of 4.926 g of intermediate a1-5 was used for the reaction. After completion of the reaction, the 7 batches were combined, extracted with ethyl acetate, concentrated, and subjected to silica gel column chromatography (hexane:ethyl acetate=80:20) to obtain intermediate a1-6 (2.223 g, 52% yield). .
¹ H NMR (CDCl ₃ , 300 MHz) δ 7.02 (1 H, s), 6.76 (1 H, dd, J = 17.7, 11.0 Hz), 6.43 (1 H, s), 5.53 ( 1H, d, J = 17.6 Hz), 5.35 (1 H, d, J = 10.9 Hz), 3.91 (2H, brs).

<Step 7>
Intermediate a1-6 (3.008 g, 16.59 mmol), 2-ethylhexanal (9.297 g, 72.51 mmol), sodium triacetoxyborohydride (15.38 g, 72.58 mmol) and 1,2-dichloroethane (82.5 mL) were added, and the mixture was stirred at room temperature for 7.5 hours. After adding saturated aqueous sodium bicarbonate, the mixture was extracted with dichloromethane, dried over magnesium sulfate, concentrated, and purified by silica gel column chromatography (hexane 100%) to obtain intermediate a2-7 (369.1 mg, 6% yield). .
¹ H NMR (CDCl ₃ , 400 MHz) δ 6.91 (1 H, s), 6.76 (1 H, dd, J = 17.6, 11.0 Hz), 6.05 (1 H, s), 5.57 ( 1H, d, J = 17.6Hz), 5.33 (1H, d, J = 11.0Hz), 3.14 (4H, d, J = 9.8Hz), 1.88-1.77 (2H , m), 1.44-1.21 (16H, m), 0.93-0.85 (12H, m).

<Step 8>
Intermediate a2-7 (249.9 mg, 0.6160 mmol), 3,4-dihydroxy-3-cyclobutene-1,2-dione (37.8 mg, 0.331 mmol), orthogyl Trimethyl acid (0.33 mL, 3.0 mmol) and 1-propanol (30 mL) were added, and the mixture was heated under reflux at 80° C. for 2 hours. After completion of the reaction, the solvent was removed and the compound (9) (39.7 mg, 14% yield) was obtained by silica gel chromatography (hexane:ethyl acetate=80:20).
¹ H NMR (CDCl ₃ , 300 MHz) δ 8.59 (2H, dd, J = 17.6, 11.1 Hz), 6.09 (2H, s), 5.73 (2H, d, J = 17.3 Hz ), 5.72 (2H, d, J = 11.4 Hz), 3.33 (8H, d, J = 7.3 Hz), 2.00-1.87 (4H, m), 1.45-1 .21 (32 H, m), 0.99-0.85 (24 H, m).

Compound 10: Synthesized according to the reaction route shown below.

<Steps 1 and 2>
Intermediate a1-2 was obtained by the same steps as Steps 1 and 2 of the method for producing compound (9).

<Step 3>
Intermediate a1-2 (83.66 g, 272.9 mmol), THF (175 mL), ethanol (175 mL), sodium hydroxide aqueous solution (1.0 M, 430 mL, 430 mmol) was added to a nitrogen-substituted eggplant flask (2 L), The mixture was heated and stirred at 40° C. for 1 hour. After completion of the reaction, hydrochloric acid (1.0 M, 450 mL) was added at 0° C. for acidification, and the organic solvent was removed under reduced pressure, followed by filtration using a hydrophilic membrane filter. The filtrate was washed with water and then water:methanol (=1:1) mixed solvent, the solvent was removed by toluene azeotrope, and dried in vacuo to give intermediate a4-3 (79.4 g, >99% yield). got
¹ H NMR (DMSO-d ₆ , 300 MHz) δ 13.51 (1 H, brs), 8.23 (1 H, s), 8.08 (1 H, s).

<Step 4>
Intermediate a4-3 (26.53 g, 100.8 mmol), toluene (200 mL), triethylamine (21.0 mL, 151 mmol), diphenylphosphoryl azide (30.62 g, 111.3 mmol) were placed in a nitrogen-substituted eggplant flask (300 mL). was added, and the mixture was heated and stirred at 60°C for 30 minutes. After completion of the reaction, a saturated aqueous sodium bicarbonate solution and ethyl acetate were added at 0°C to separate the layers. The resulting organic layer was washed with a saturated aqueous sodium bicarbonate solution, water and saturated brine, dried over sodium sulfate, concentrated, and washed with hexane. After that, it was vacuum-dried to obtain intermediate a4-4 (25.24 g, 96% yield).
¹ H NMR (CDCl ₃ , 400 MHz) δ 8.05 (1 H, s), 7.55 (1 H, s).

<Step 5>
Intermediate a4-4 (12.01 g, 46.19 mmol), t-butyl alcohol (100 mL) and toluene (100 mL) were added to a nitrogen-substituted eggplant flask (500 mL), and the mixture was heated and stirred at 80° C. for 15 hours. After completion of the reaction, it was concentrated, dissolved in dichloromethane, filtered through silica gel, the solvent was distilled off, and the intermediate a4-5 (12.21 g, 79% yield) was obtained by vacuum drying.
¹ H NMR (DMSO-d ₆ , 300 MHz) δ 10.80 (1 H, s), 7.50 (1 H, s), 6.92 (1 H, s), 1.49 (9 H, s).

<Steps 6-7>
Intermediate a4-5 (12.20 g, 36.49 mmol), sodium iodide (11.00 g, 73.40 mmol) and acetonitrile (370 mL) were added to a nitrogen-substituted eggplant flask (1 L) and chlorotrimethylsilane ( 7.776 g, 71.58 mmol) was added. After stirring with heating for 16.5 hours, saturated aqueous sodium bicarbonate solution and ethyl acetate were added at room temperature to separate the layers, and the organic layer was washed with saturated aqueous sodium bicarbonate solution, water and saturated brine. 2-Ethylhexanal (7.021 g, 54.76 mmol) and sodium sulfate were added to the resulting organic layer and allowed to stand for 15 minutes, filtered, and the solvent was distilled off. The obtained was transferred to a 4-necked flask (1 L), methanol (270 mL), acetic acid (37 mL) and 2-ethylhexanal (14.05 g, 109.6 mmol) were added, stirred at -10°C under a nitrogen atmosphere, A solution of 2-picoline borane (7.900 g, 71.65 mmol) in methanol (100 mL) was added dropwise over 10 minutes. After stirring for 19 hours, a saturated aqueous sodium bicarbonate solution, hexane and ethyl acetate were added to separate the layers, and the resulting organic layer was washed with a saturated aqueous sodium bicarbonate solution, water and saturated brine, dried over sodium sulfate and concentrated to obtain a crude product. Obtained. After removal of starting aldehyde by NH ₂ silica gel filtration, intermediate a4-7 (12.01 g, 72% yield) was obtained by silica gel column chromatography (hexane 100%).
¹ H NMR (CDCl ₃ , 300 MHz) δ 6.98 (1 H, s), 6.14 (1 H, s), 3.13 (4 H, d, J=7.5 Hz), 1.91-1.75 ( 2H, m), 1.45-1.21 (16H, m), 1.00-0.82 (12H, m).

<Step 8>
Intermediate a4-7 (1.994 g, 4.349 mmol), methyl acrylate (560.4 mg, 6.509 mmol), triethylamine (1.300 g, 12.84 mmol), acetic acid were placed in a two-neck flask (50 mL) purged with nitrogen. Palladium (II) (49.9 mg, 0.222 mmol), triorthotolylphosphine (132.8 mg, 0.4363 mmol) and DMF (25.0 mL) were added, and the mixture was heated and stirred at 85°C for 3 hours. After completion of the reaction, a saturated aqueous ammonium chloride solution was added at 0°C, extracted with hexane/ethyl acetate, washed with water and saturated brine, dried over magnesium sulfate, concentrated, and subjected to silica gel column chromatography (hexane:ethyl acetate = 20:20). 1) yielded intermediate a9-8 (461.9 mg, 23% yield).
¹ H NMR (CDCl ₃ , 300 MHz) δ 7.71 (1 H, d, J=16.1 Hz), 7.24 (1 H, s), 6.23 (1 H, d, J=15.8 Hz),6. 04 (1H, s), 3.82 (3H, s), 3.15 (4H, d, J=7.3Hz), 1.47-1.21 (16H, m), 0.96-0. 83 (12H, m).

<Step 9>
Intermediate a9-8 (461.9 mg, 0.996 mmol), 3,4-dihydroxy-3-cyclobutene-1,2-dione (172.2 mg, 1.509 mmol), orthogyl Trimethyl acid (1.279 g, 12.05 mmol) and 1-propanol (50 mL) were added, and the mixture was heated and stirred at 80° C. for 1.5 hours. After completion of the reaction, the mixture was concentrated to about half volume, hexane, ethyl acetate and saturated aqueous sodium bicarbonate were added to separate the layers, and the resulting organic layer was washed with water, dried over sodium sulfate, concentrated, and washed with hexane. The obtained solid was purified by silica gel column chromatography (dichloromethane:ethyl acetate=30:1) to obtain compound (10) (345.5 mg, 69% yield).
¹ H NMR (CDCl ₃ , 300 MHz) δ 9.57 (2H, d, J = 14.3 Hz), 6.32 (2H, d, J = 16.1 Hz), 6.13 (2H, s), 3. 94 (6H, s), 3.35 (8H, d, J=7.1Hz), 2.00-1.87 (4H, m), 1.48-1.23 (32H, m), 1. 01-0.85 (24H, m).

Compound 11: Synthesized based on WO2019/230660.

Compound 12: Synthesized according to the reaction route shown below.

(Step 1): Compound (1x) (3-amino-2-methoxypyridine manufactured by Tokyo Kasei) (2.5 g) was dissolved in dichloromethane (60 ml), diisopropylethylamine (2.8 g) and acetic anhydride (2.25 g). ) was added and stirred at room temperature for 3 hours. The product was purified by silica gel column chromatography method to give compound (2x) (yield 94%).
(Step 2): Trifluoroacetic anhydride (7.5 ml) was added to compound (2x) (2.5 g) at 0°C and stirred for 30 minutes. A mixed solution of fluoroacetic acid (12 g) was added dropwise at 0°C. After stirring for 12 hours at room temperature, 2.4 g of a solid of compound (3x) emerged upon neutralization with aqueous sodium hydroxide (yield 76%).
(Step 3): Compound (3x) (1.9 g) was dissolved in methanol (50 ml), 1M hydrochloric acid (18 ml) was added and stirred at 60°C for 12 hours. After removing the methanol, it was neutralized and 1.47 g of solid compound (4x) was filtered off (yield 96%).
(Step 4): Compound (4x) (5.1 g) was dissolved in dichloromethane (80 ml), 2-ethylhexylaldehyde (42 ml) (20 eq), triacetoxyborohydride (25 g) (4 eq), acetic acid (0 .2 ml) was added and stirred at room temperature for 4 hours. After adding alkali to pH 7, the mixture was separated with dichloromethane/water, and the concentrated organic layer was purified by silica gel chromatography to obtain compound (5x) (5.9 g) (yield 78%).
(Step 5): Compound (5x) (5.9 g) was dissolved in methanol, palladium carbon (3 g) was added, and the mixture was stirred under hydrogen atmosphere for 5 hours. Water was added, palladium was removed by celite filtration, and after methanol was removed, liquid separation was performed with ethyl acetate/water to obtain the target compound (6) (3.7 g) (yield 71%).
(Step 6): Compound (6x) (3.7 g) was dissolved in dichloromethane (50 ml) and diisopropylethylamine (2.36 g) was added. The solution was cooled to 0° C. and isobutyl chloroformate (2.7 g) was added and stirred at room temperature for 12 hours. After completion of the reaction, the mixture was separated with dichloromethane/water, and the organic layer was concentrated and purified by column chromatography to obtain the target compound (7x) (yield 88%).
(Step 7): Compound (7x) (5.8 g) was dissolved in 150 ml of acetonitrile, and 3 equivalents each of TMS-Cl (5.4 g) and sodium iodide (7.5 g) were added. After reacting at 80° C. for 3 hours, it was concentrated and purified by column chromatography to give the target compound (8x) (2 g) (yield 35%).
(Step 8): Compound (8x) and 0.6 equivalents of 3,4-dihydroxy-3-cyclobutene-1,2-dione were added and reacted in 1-butanol at 110°C for 16 hours. After completion of the reaction, all the solvent was removed, the product was purified by a column, and extracted with an acetic acid/methanol solution to obtain squarylium compound (12) in a yield of 35%.

Compounds 13-15: Synthesized based on WO2017/135359.
In compounds 13 to 15, indolines were synthesized according to the following method.
In compound 13, 2,3,3-trimethylindolenine is reacted with an excess amount of sodium borohydride in an acetic acid solvent, and further reacted with isobutyraldehyde to give N-isobutyl-2,3,3-trimethylindoline. Synthesized.
In compound 14, indolenine was synthesized by reacting isobutyronitrile and isobutylmagnesium, and further reacting phenylhydrazine. N-propyl-2-isobutyl-3,3-dimethylindoline was synthesized by reacting this indolenine with an excess amount of sodium borohydride in an acetic acid solvent and further reacting it with propionaldehyde.
In compound 15, indolenine was synthesized by reacting 2,3-dimethylindole with ethylmagnesium bromide and then with methallyl chloride. N-ethyl-3-isobutyl-2,3-dimethylindoline was synthesized by reacting this indolenine with an excess amount of sodium borohydride in an acetic acid solvent, and further reacting it with acetaldehyde.

Compound 16: Synthesized based on the method described in Dyes and Pigments 73 (2007) 344-352.

As the liquid crystal compound, the following non-polymerizable nematic liquid crystal compound (ZLI-1132 manufactured by LCC Co., Ltd.) was used.

<Production and Evaluation of Dichroic Dye Composition>
(Example 1)
The dichroic dye composition of Example 1 having a squarylium dye content of 0.19% by mass (0.34 mmol relative to 100 parts by mass of the liquid crystal compound) was obtained by mixing the squarylium dye of compound 1 below with the above liquid crystal compound. Obtained.
The resulting dichroic dye composition was injected into a horizontally aligned cell manufactured by EHC Co., Ltd. in which a gap of 5 μm was maintained, and irradiated with polarized light parallel to and perpendicular to the rubbing direction. The dichroic ratio was measured by measuring (A|| and A⊥) with a visible absorption spectrometer (manufactured by Shimadzu Corporation).

(Example 2)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 2 was used as the squarylium dye and the content of the squarylium dye was 0.24% by mass (0.30 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 3)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 3 was used as the squarylium dye and the content of the squarylium dye was 0.21% by mass (0.34 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 4)
The dichroic ratio was measured in the same manner as in Example 1 except that the following compound 4 was used as the squarylium dye and the content of the squarylium dye was 0.10% by mass (0.22 mmol relative to 100 parts by mass of the liquid crystal compound).

(Example 5)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 5 was used as the squarylium dye and the content of the squarylium dye was 0.18% by mass (0.27 mmol relative to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 6)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 6 was used as the squarylium dye and the content of the squarylium dye was 0.16% by mass (0.33 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 7)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 7 was used as the squarylium dye and the content of the squarylium dye was 0.16% by mass (0.33 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 8)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 8 was used as the squarylium dye and the content of the squarylium dye was 0.25% by mass (0.30 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 9)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 9 was used as the squarylium dye and the content of the squarylium dye was 0.20% by mass (0.22 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 10)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 10 was used as the squarylium dye and the content of the squarylium dye was 0.50% by mass (0.50 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 11)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 11 was used as the squarylium dye and the content of the squarylium dye was 0.31% by mass (0.33 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 12)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 12 was used as the squarylium dye and the content of the squarylium dye was 0.20% by mass (0.20 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 13)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 13 was used as the squarylium dye and the content of the squarylium dye was 0.16% by mass (0.27 mmol with respect to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 14)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 14 was used as the squarylium dye and the content of the squarylium dye was 0.17% by mass (0.26 mmol relative to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 15)
A dichroic dye composition was prepared in the same manner as in Example 1 except that the following compound 15 was used as the squarylium dye and the content of the squarylium dye was 0.19% by mass (0.30 mmol relative to 100 parts by mass of the liquid crystal compound). and measured the dichroic ratio.

(Example 16)
In the same manner as in Example 1, except that the following compound 16 was used as a cyanine dye instead of the squarylium dye, and the content of the cyanine dye was 0.25% by mass (0.32 mmol with respect to 100 parts by mass of the liquid crystal compound). A dye composition was prepared and the dichroic ratio was measured.

The dichroic ratio of each of the above dichroic dye compositions is shown in the table below.
Examples 1 to 15 are working examples, and example 16 is a comparative example.

From the above results, all the dichroic dye compositions of Examples exhibited excellent dichroism.

The dichroic dye composition of the present invention is useful as a material for optical elements such as liquid crystal elements, polarizers and retardation plates. Moreover, since the dichroic dye composition of the present invention has near-infrared absorbing power, it is particularly useful for sensors of near-infrared light and infrared light.

Claims (13)

A dichroic dye composition comprising a squarylium dye containing a heteroatom and a liquid crystal compound that transmits visible light. The dichroic dye composition according to claim 1, wherein the squarylium dye is a compound represented by the following formula (X).

[The symbols in the formula (X) are as follows.
Ar is an aromatic monocyclic, condensed or linked ring having 5 to 14 carbon atoms.
Each of R ¹ and R ² is independently a hydrogen atom or one having 1 to 20 carbon atoms which may have a substituent and may contain an unsaturated bond, hetero atom or ring structure between carbon atoms. indicates a valent hydrocarbon group.
The carbon atoms constituting R ¹ and R ² , or at least one of R ¹ and R ² and Ar may be linked together to form a 3- to 10-membered heterocyclic ring together with the nitrogen atom. ] The dichroic dye composition according to claim 1 or 2, wherein the squarylium dye is a compound represented by the following formula (I).

[The symbols in the above formula are as follows.
R ¹¹ and R ²¹ are each independently a hydrogen atom, an optionally substituted alkyl group or an alkoxy group having 1 to 20 carbon atoms which may contain an unsaturated bond or a hetero atom between carbon atoms; an acyloxy group having 1 to 19 carbon atoms, an aryl group having 6 to 11 carbon atoms, or an araryl group having 7 to 18 carbon atoms, optionally having a substituent and having an oxygen atom between the carbon atoms indicates
R ³¹ and R ⁵¹ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 8 carbon atoms, an acyloxy group having 1 to 8 carbon atoms, an aryl group having 6 to 9 carbon atoms, an araryl group having 7 to 9 carbon atoms which may have a substituent and which may have an oxygen atom between the carbon atoms, —NR ^31a R ^31b (R ^31a and R ^31b are each independently a hydrogen atom, Alkyl group having 1 to 4 carbon atoms, -C(=O)-R ^31c (R ^31c may have a hydrogen atom, a halogen atom, a hydroxyl group, a substituent, an unsaturated bond between carbon atoms, an oxygen atom , a hydrocarbon group having 1 to 8 carbon atoms which may contain a saturated or unsaturated ring structure), —NHR ^31d , or —SO ₂ —R ^31d (R ^31d has one or more hydrogen atoms each substituted with a halogen atom , a hydroxyl group, a carboxy group, a sulfo group, or a cyano group, and may contain an unsaturated bond between carbon atoms, an oxygen atom, a saturated or unsaturated ring structure, and a hydrocarbon group having 1 to 8 carbon atoms. ), or a group represented by formula (S) below (R ^31e and R ^31f independently represent a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 3 carbon atoms. k is 2 or 3.).

R ⁴¹ and R ⁶¹ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl or alkoxy group having 1 to 8 carbon atoms, an acyloxy group having 1 to 8 carbon atoms, an aryl group having 6 to 9 carbon atoms, Alternatively, it represents an araryl group having 7 to 9 carbon atoms which may have a substituent and which may have an oxygen atom between carbon atoms.
R ¹¹ and R ²¹ , R ¹¹ and R ⁴¹ , and R ²¹ and R ⁶¹ are each linked together with a nitrogen atom to form a 4- to 6-membered heterocyclic ring A1, a 5- to 7-membered heterocyclic ring B1, and A 5- to 7-membered heterocyclic ring C1 may be formed. ] The dichroic dye composition according to claim 1 or 2, wherein the squarylium dye is a compound represented by the following formula (II).

[The symbols in the above formula are as follows.
Each ring Z2 is independently a 5- or 6-membered ring having 0 to 3 heteroatoms in the ring, and the hydrogen atoms of ring Z2 may be substituted.
R ¹² and R ²² each independently contain a hydrogen atom, or an unsaturated bond between carbon atoms, a hetero atom, a saturated or unsaturated ring structure, and the number of carbon atoms that may have a substituent It represents a 1-20 monovalent hydrocarbon group.
R ³² and R ⁴² each independently represent a hydrogen atom, a halogen atom, or an optionally substituted alkyl or alkoxy group having 1 to 8 carbon atoms which may contain a heteroatom between carbon atoms; show.
The carbon atoms or heteroatoms constituting R ¹² and R ²² , R ¹² and R ⁴² , and R ²² and ring Z2 are linked together with a nitrogen atom to form a 4- to 6-membered heterocyclic ring A2 and a 5- to 5-membered heterocyclic ring A2. 7 heterocycle B2 and 5- to 7-membered heterocycle C2 may be formed. ] The dichroic dye composition according to claim 1 or 2, wherein the squarylium dye is a compound represented by the following formula (III).

[The symbols in the above formula are as follows.
each of R ¹³ and R ²³ independently may have a substituent and may contain an unsaturated bond between carbon atoms, a hetero atom, an alicyclic ring or an aromatic ring, and an alkyl group having 1 to 20 carbon atoms; is.
R ³³ is an organic group R ^33A not essentially having an unsaturated bond or an organic group R ^33B essentially having an unsaturated bond.
^X31 is ^CR43 or N;
X ³² is S, NR ⁵³ , or O;
^X33 is S, ^NR63 , or O;
R ⁴³ is a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carbonyl structure-containing monovalent organic group, a phosphate group, a silyl group, a thiol group, a sulfide group, an amide structure-containing monovalent organic group, a sulfone amide group, urea group, urethane structure-containing monovalent organic group, optionally substituted C1-C9 alkyl group, optionally substituted C2-C9 alkenyl group, substituent an alkynyl group having 2 to 9 carbon atoms which may have a substituent, an aryl group having 6 to 9 carbon atoms which may have a substituent, a heteroaryl group having 3 to 9 carbon atoms which may have a substituent, an optionally substituted alkoxy group having 1 to 9 carbon atoms, an optionally substituted acyloxy group having 2 to 9 carbon atoms, or —N(R ^43g ) ₂ (R ^43g is a hydrogen atom or It is an optionally substituted alkyl group having 1 to 4 carbon atoms.).
R ⁵³ and R ⁶³ are each independently a hydrogen atom, a monovalent organic group containing a carbonyl structure, a sulfo group, or an optionally substituted alkyl group having 1 to 9 carbon atoms.
R ¹³ may be combined with R ²³ , R ³³ , X ³¹ , X ³² or X ³³ to form a 3-6 membered ring.
R ²³ may be combined with R ¹³ , R ³³ , X ³¹ , X ³² or X ³³ to form a 3-6 membered ring.
R ³³ may be combined with X ³¹ , X ³² or X ³³ to form a 5- to 7-membered ring. ] The dichroic dye composition according to claim 1 or 2, wherein the squarylium dye is a compound represented by the following formula (IV).

[The symbols in the above formula are as follows.
R ¹⁴ and R ²⁴ each independently may have a substituent and may contain an unsaturated bond between carbon atoms, a hetero atom, an alicyclic ring or an aromatic ring and has 1 to 20 carbon atoms. is an alkyl group.
R ³⁴ is an organic group R ^34A not essentially having an unsaturated bond or an organic group R ^34B essentially having an unsaturated bond.
^X41 is ^CR43 or N;
X ⁴² is S, NR ⁵³ , or O;
X ⁴³ is S, NR ⁶³ , or O;
R ⁴³ is a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carbonyl structure-containing monovalent organic group, a phosphate group, a silyl group, a thiol group, a sulfide group, an amide structure-containing monovalent organic group, a sulfone amide group, urea group, urethane structure-containing monovalent organic group, optionally substituted C1-C9 alkyl group, optionally substituted C2-C9 alkenyl group, substituent an alkynyl group having 2 to 9 carbon atoms which may have a substituent, an aryl group having 6 to 9 carbon atoms which may have a substituent, a heteroaryl group having 3 to 9 carbon atoms which may have a substituent, an optionally substituted alkoxy group having 1 to 9 carbon atoms, an optionally substituted acyloxy group having 2 to 9 carbon atoms, or —N(R ^43g ) ₂ (R ^43g is a hydrogen atom or It is an optionally substituted alkyl group having 1 to 4 carbon atoms.).
R ⁴⁴ , R ⁵⁴ , R ⁶⁴ and R ⁷⁴ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, or a monovalent organic group having 1 to 9 carbon atoms.
R ¹⁴ may be combined with R ²⁴ , R ⁵⁴ or R ⁷⁴ to form a 3-6 membered ring.
R ²⁴ may be combined with R ¹⁴ , R ⁵⁴ or R ⁷⁴ to form a 3-6 membered ring. ] The dichroic dye composition according to claim 1 or 2, wherein the squarylium dye is a compound represented by the following formula (V).

[The symbols in the above formula are as follows.
R ¹⁵ and R ²⁵ each independently may have a substituent, an unsaturated bond between carbon atoms, an alkyl group having 1 to 20 carbon atoms which may contain a hetero atom, or an alkyl group having 4 to 4 carbon atoms 20 araryl groups.
R ³⁵ , R ⁴⁵ , R ⁵⁵ and R ⁶⁵ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an optionally substituted alkyl group having 1 to 9 carbon atoms, an optionally substituted It is an aryl group having 4 to 9 carbon atoms or an araryl group having 5 to 9 carbon atoms which may have a substituent.
R ³⁵ and R ⁴⁵ , R ⁴⁵ and R ⁵⁵ , and R ⁵⁵ and R ⁶⁵ may be linked to each other to form a monocyclic ring or a polycyclic ring in which 2 to 4 rings are condensed.
R ¹⁵ and R ²⁵ may be linked together to form a 4- to 10-membered heterocyclic ring with the nitrogen atom. ] The dichroic dye composition according to claim 1 or 2, wherein the squarylium dye is a compound represented by the following formula (VI).

[The symbols in the above formula are as follows.
R ¹⁶ and R ²⁶ each independently may have a substituent and may contain an unsaturated bond between carbon atoms, a hetero atom, an alicyclic ring or an aromatic ring and has 1 to 20 carbon atoms. is an alkyl group.
R ³⁶ is a monovalent organic group having 9 or less carbon atoms containing an atom having a lone pair of electrons.
R ⁴⁶ is a hydrogen atom or an alkyl group having 1 to 9 carbon atoms.
R ⁵⁶ is a hydrogen atom or an alkyl group having 1 to 9 carbon atoms.
X ⁶¹ is C=O, C ₌ S, or SO2.
R ¹⁶ and R ²⁶ , R ¹⁶ and R ⁴⁶ , R ³⁶ and R ⁴⁶ may be linked together to form a 3- to 6-membered ring. ] The dichroic dye composition according to any one of claims 1 to 8, wherein the content of the liquid crystal compound is 50% by mass or more. A liquid crystal element comprising a pair of electrode substrates and a liquid crystalline layer formed between the pair of electrode substrates,
A liquid crystal device, wherein the liquid crystalline layer is formed from the dichroic dye composition according to any one of claims 1 to 9. A retardation plate comprising a substrate and a refractive index anisotropic film formed on at least one principal surface side of said substrate, or a pair of substrates and a refractive index anisotropic film formed between said pair of substrates a retardation plate comprising a film,
A retardation plate, wherein the refractive index anisotropic film is formed from the dichroic dye composition according to any one of claims 1 to 9. A polarizer comprising a substrate and an anisotropic light absorption film formed on at least one main surface side of said substrate, or a pair of substrates and an anisotropic light absorption film formed between said pair of substrates A polarizer comprising
A polarizer, wherein the light absorption anisotropic film is formed from the dichroic dye composition according to any one of claims 1 to 9. An imaging device, a light wave ranging device, a virtual reality device, or a solar radiation control member comprising an optical element formed from the dichroic dye composition according to any one of claims 1 to 9.