Novel squarylium compound, near infrared absorbing dye and thin film

Abstract

To provide a compound that exhibits absorption in the near-infrared light region and has high thermal resistance.SOLUTION: A squarylium compound represented by the following general formula (1): in the formula, L1 and L2 represent a single bond, an alkenylene group, a divalent aromatic hydrocarbon group, or a divalent aromatic heterocyclic group; R1 and R2 represent an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, aromatic hydrocarbon group, or aromatic heterocyclic group; Ar1 and Ar2 represent a hydrogen atom, amino group, aromatic hydrocarbon group, or aromatic heterocyclic group; and m and n each represent an integer of 1 or 2.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a novel squarylium compound, a near-infrared absorbing dye containing the compound, and a thin film.

Background Art

[0002] In recent years, for dye compounds, although the needs for fastness, particularly light resistance and weather resistance, and the demand for dyes rather than pigments (functions in films and molecular dispersion states) have been increasing, the molecular design for adjusting various physical properties has reached a deadlock. For this reason, the search for dye compounds based on novel skeletons has been underway.

[0003] A near-infrared absorbing dye is a dye having absorption in the near-infrared region (700 to 2000 nm) with a longer wavelength than visible light, and exhibits strong light absorption based on the charge transfer of organic dyes and metal complexes. Since near-infrared light has high biopermeability and is abundant in sunlight, various developments using near-infrared light have been carried out, and photoelectric conversion elements such as organic thin-film solar cells and dye-sensitized solar cells, NeuralDensity (ND) filters, the security field, agricultural films, dimming filters (heat shielding / semiconductor sensors), and photodynamic therapy, etc., are expected to be applied in a wide range of fields.

[0004] As near-infrared absorbing materials, there are inorganic materials and organic materials. As inorganic materials, rare earth metals such as ytterbium and copper phosphate crystallized glass are known. However, since inorganic materials do not have sufficient light absorbability in the near-infrared region, a large amount of material is required. On the other hand, since organic materials have sufficient light absorbability in the near-infrared region, the development as near-infrared absorbing materials has been vigorously promoted.

[0005] Although organic dyes with phthalocyanine or rhodamine as the parent nucleus have been synthesized as organic near-infrared absorbing materials, the types and number of such dyes are limited. Furthermore, most of these dyes also absorb visible light (Patent Document 1), so there are few organic dyes suitable for applications requiring transparency, such as near-infrared absorbing films.

[0006] In addition, near-infrared absorbing dyes can be dissolved or dispersed in a solvent and used as a solution or dispersion. When a dye solution is applied to form a film, the solubility of the dye is necessary, and when forming a film, the molecular structure plays a major role. Therefore, there is a need to develop a near-infrared absorbing dye that absorbs near-infrared light and has relatively little absorption in the visible light region, has solubility suitable for a coating film when used in solution, has high heat resistance, and is easy to handle. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-116717 [Patent Document 2] International Publication No. 2017 / 104283 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a compound that has absorption in the near-infrared region and high heat resistance, and to provide a near-infrared absorbing dye and a thin film using the compound. [Means for solving the problem]

[0009] To solve the above problems, the inventors of the present invention focused on the dithienopyrrole skeleton and conducted intensive studies in the development of novel near-infrared absorbing dyes. As a result, it has been found that a squarylium compound having a dithienopyrrole skeleton is useful as a near-infrared absorbing dye that solves the above problems. That is, the present invention has the following gist.

[0010] [1] A squarylium compound represented by the following general formula (1):

[0011] [Chemical formula]

[0012] In the formula, L 1 and L 2 each independently represents a single bond, a linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent, a divalent aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or a divalent aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, R 1 and R 2 each independently represents a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent, a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent, a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, Ar 1 and Ar 2 each independently represents a hydrogen atom, An amino group having 6 to 36 carbon atoms which may have a substituent, An aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or An aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, m and n each independently represent an integer of 1 or 2.

[0013] [2] In the general formula (1), Ar 1 and Ar 2 each independently represent a hydrogen atom or a group represented by the following general formula (2): The squarylium compound according to [1],

[0014] [Chemical formula]

[0015] In the formula, R 3 and R 4 each independently represent A linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, A cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, An aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or An aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, R 3 and R 4 may be bonded to each other to form a ring, Z 1 represents an oxygen atom or a sulfur atom, x and y each independently represent an integer of 0 or 1.

[0016] [3] In the general formula (1), R 1 and R 2are each independently an optionally substituted linear or branched alkyl group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 36 carbon atoms, or an optionally substituted aromatic heterocyclic group having 5 to 36 ring atoms.

[0017] [4] A near-infrared absorbing dye comprising the squarylium compound according to any one of [1] to [3].

[0018] [5] A thin film comprising the squarylium compound according to any one of [1] to [3]. [Effects of the Invention]

[0019] The squarylium compound according to the present invention can provide a near-infrared absorbing dye having absorption characteristics mainly in the near-infrared region and high heat resistance. Furthermore, thin films prepared using the squarylium compound can be applied to organic electronic devices such as solar cells having excellent photoelectric conversion performance. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is an ultraviolet-visible-near infrared absorption spectrum of the compound (A-1) obtained in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described in detail. The following description is an example of an embodiment of the present invention, and the present invention is not limited to these details. The novel compound having a squarylium skeleton of the present invention can be used in near-infrared absorbing dyes and thin films containing the compound, and organic electronic devices such as photoelectric conversion elements containing them.

[0022] <Squarylium compounds> The squarylium compound according to the present invention is a compound represented by the general formula (1). Hereinafter, the squarylium compound according to the present invention will be specifically described.

[0023] In general formula (1), L 1 and L 2 each independently represents a single bond, a linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent, a divalent aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or a divalent aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent. Note that, for L 1 and L 2 being a single bond means that in general formula (1), the squarylium skeleton and the dithienopyrrole skeleton are directly bonded.

[0024] L 1 and L 2 Specific examples of the "linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent" represented by L

[0025] L 1 and L 2Specific examples of the "divalent aromatic hydrocarbon group having 6 to 36 carbon atoms" in the "divalent aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by the formula (1) include divalent aromatic hydrocarbon groups (arylene groups) obtained by removing one hydrogen atom from aromatic hydrocarbon groups such as phenyl, biphenylyl, terphenylyl, naphthyl, anthryl, phenanthryl, fluorenyl, indenyl, pyrenyl, perylenyl, fluoranthenyl, and triphenylenyl groups. In the present invention, the "aromatic hydrocarbon group" includes a "condensed polycyclic aromatic group."

[0026] L 1 and L 2 Specific examples of the "divalent aromatic heterocyclic group having 5 to 36 ring atoms" in the "divalent aromatic heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the following formula (1) include a pyridyl group, a pyrimidinyl group, a triazinyl group, a thienyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, an acridinyl group, a phenanthrolinyl group, a benzofurafyl group, a Examples of such a heterocyclic group include a divalent aromatic heterocyclic group obtained by removing one hydrogen atom from a monovalent aromatic heterocyclic group such as an indolyl group, a benzothienyl group, an oxazolyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a dithienopyrrolyl group, an iminostilbenyl group, and a carbolinyl group.

[0027] L 1 and L 2Examples of the "substituent" in the "optionally substituted linear or branched alkenylene group having 2 to 20 carbon atoms," "optionally substituted divalent aromatic hydrocarbon group having 6 to 36 carbon atoms," or "optionally substituted divalent aromatic heterocyclic group having 5 to 36 ring atoms" represented by the above formula (I) specifically include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; a cyano group; a hydroxyl group; a nitro group; a nitroso group; a carboxyl group; a phosphate group; a carboxylic acid ester group such as a methyl ester group or an ethyl ester group; a methyl group, an ethyl ... linear or branched alkyl groups having 1 to 19 carbon atoms, such as a vinyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group, a 2-ethylhexyl group, a heptyl group, an octyl group, an isooctyl group, a nonyl group, or a decyl group; linear or branched alkenyl groups having 2 to 18 carbon atoms, such as a vinyl group, a 1-propenyl group, an allyl group, a 1-butenyl group, a 2-butenyl group, a 1-pentenyl group, a 1-hexenyl group, an isopropenyl group, or an isobutenyl group; a methoxy group, Alkoxy groups having 1 to 20 carbon atoms, such as ethoxy, propoxy, t-butoxy, pentyloxy, and hexyloxy; aromatic hydrocarbon groups having 6 to 19 carbon atoms, such as phenyl, naphthyl, anthryl, phenanthryl, and pyrenyl; pyridyl, pyrimidinyl, triazinyl, thienyl, furyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, quinolyl, isoquinolyl, naphthyridinyl, acridinyl, phenanthrolinyl, benzofuranyl, benzothienyl, oxazolyl, and isoquinolyl groups. Aromatic heterocyclic groups having 5 to 19 ring atoms, such as an indolyl group, a carbazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a dithienopyrrolyl group, an iminostilbenyl group, and a carbolinyl group; amino groups having 0 to 20 carbon atoms, such as an unsubstituted amino group (-NH2), a monosubstituted amino group such as an ethylamino group, an acetylamino group, or a phenylamino group, or a disubstituted amino group such as a diethylamino group, a diphenylamino group, or an acetylphenylamino group;Thio groups with 0 to 20 carbon atoms such as unsubstituted thio group (thiol group: -SH), methylthio group, ethylthio group, propylthio group, hexa-5-en-3-thio group, phenylthio group, biphenylthio group; monosubstituted amide groups (-C(=O)NHR such as unsubstituted amide group (-C(=O)NH2), ethylamide group, acetylamide group, phenylamide group; a1 ), or disubstituted amide groups (-C(=O)NR a1 R a2 ) such as diethylamide group, dihexylamide group, diphenylamide group, etc., which are amide groups with 0 to 20 carbon atoms (wherein R a1 and R a2 represent a linear or branched alkyl group with 1 to 20 carbon atoms or an aromatic hydrocarbon group with 6 to 20 carbon atoms); and the like can be mentioned. Note that these "substituents" may contain only one, or may contain a plurality. When a plurality are contained, they may be the same as or different from each other. Also, these "substituents" may further have the substituents exemplified above.

[0028] In general formula (1), R 1 and R 2 each independently represent a linear or branched alkyl group with 1 to 20 carbon atoms which may have a substituent, a linear or branched alkenyl group with 2 to 20 carbon atoms which may have a substituent, a linear or branched alkynyl group with 2 to 20 carbon atoms which may have a substituent, a cycloalkyl group with 3 to 10 carbon atoms which may have a substituent, an aromatic hydrocarbon group with 6 to 36 carbon atoms which may have a substituent, or an aromatic heterocyclic group with 5 to 36 ring-forming atoms which may have a substituent.

[0029] R 1 and R 2Specific examples of the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group (Hex), a 2-ethylhexyl group (2-EtHex), a heptyl group, an octyl group, an isooctyl group, a nonyl group, and a decyl group, etc.

[0030] R 1 and R 2 Specific examples of the "linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by include a vinyl group, a 1-propenyl group, an allyl group, a 1-butenyl group, a 2-butenyl group, a 1-pentenyl group, a 1-hexenyl group, an isopropenyl group, an isobutenyl group, and a linear or branched alkenyl group having 2 to 20 carbon atoms in which a plurality of these alkenyl groups are bonded, etc.

[0031] R 1 and R 2 Specific examples of the "linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent" represented by include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 1-methyl-2-propynyl group, a 1-pentynyl group, a 2-pentynyl group, a 1-methyl-n-butynyl group, a 2-methyl-n-butynyl group, a 3-methyl-n-butynyl group, and a 1-hexynyl group, etc.

[0032] R 1 and R 2Specific examples of the "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented by include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group, etc.

[0033] R 1 and R 2 Specific examples of the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by include a phenyl group, a biphenylyl group, a terphenylyl group, a naphthyl group, an anthryl group, a phenanthryl group, a fluorenyl group, an indenyl group, a pyrenyl group, a perylenyl group, a fluoranthenyl group, and a triphenylenyl group, etc.

[0034] R 1 and R 2 Specific examples of the "aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent" represented by include a pyridyl group, a pyrimidinyl group, a triazinyl group, a thienyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, an acridinyl group, a phenanthrolinyl group, a benzofuranyl group, a benzothienyl group, an oxazolyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a dithienopyrrolyl group, an iminostilbenyl group, and a carbolinyl group, etc.

[0035] R 1 and R 2The "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent", "linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent", "linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent", "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent", "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent", or "aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent" represented by , the "substituent" therein is the above L 1 and L 2 The same as the "substituent" in the "linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent" represented by and the like can be mentioned.

[0036] In general formula (1), Ar 1 and Ar 2 each independently represents a hydrogen atom, an amino group having 6 to 36 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent.

[0037] Ar 1 and Ar 2 Specific examples of the "amino group having 6 to 36 carbon atoms" in the "amino group having 6 to 36 carbon atoms which may have a substituent" represented by include, as a monosubstituted amino group, an ethylamino group, an acetylamino group, a phenylamino group, etc., and as a disubstituted amino group, a diethylamino group, a dipropylamino group, a dibutylamino group, a diphenylamino group, an acetylphenylamino group, a di(2-ethylhexyl)amino group, etc.

[0038] Ar 1 and Ar 2 Specific examples of the "aromatic hydrocarbon group having 6 to 36 carbon atoms" in the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by are the above R 1 and R 2Examples of the "aryl group having 6 to 36 carbon atoms which may have a substituent" represented by are the same as the "aryl group having 6 to 36 carbon atoms".

[0039] Ar 1 and Ar 2 Examples of the "aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent" represented by are the same as the "aromatic heterocyclic group having 5 to 36 ring-forming atoms" in the above R 1 and R 2 Examples of the "aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent" represented by are the same as the "aromatic heterocyclic group having 5 to 36 ring-forming atoms".

[0040] Ar 1 and Ar 2 Examples of the "substituent" in the "amino group having 6 to 36 carbon atoms which may have a substituent", "aryl group having 6 to 36 carbon atoms which may have a substituent", or "aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent" represented by are the same as the "substituent" in the "linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent" represented by the above L 1 and L 2 Examples of the "substituent" in the "linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent" represented by are the same as the "substituent".

[0041] In general formula (1), m and n each independently represent an integer of 1 or 2. That is, when m is 1, n is 1 or 2, and when n is 1, m is 1 or 2. In the present invention, for convenience of compound synthesis, it is preferable that m and n are the same.

[0042] In the present invention, L 1 and L 2 are preferably a single bond, a divalent aryl group having 6 to 36 carbon atoms which may have a substituent, or a divalent aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, and more preferably a single bond or a divalent aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent. Also, L1 and L 2 When is a group having a substituent, the "substituent" is preferably a hydroxyl group, a linear or branched alkyl group having 1 to 19 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 19 carbon atoms.

[0043] In the present invention, R 1 and R 2 is preferably a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an aromatic heterocyclic group having 5 to 36 ring atoms which may have a substituent. 1 and R 2 is a group having a substituent, the "substituent" is preferably a linear or branched alkyl group having 1 to 19 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 19 carbon atoms, an amino group having 0 to 20 carbon atoms, or an amide group having 0 to 20 carbon atoms.

[0044] The compound represented by general formula (1) is preferably symmetrical with respect to the squarylium skeleton. In this specification, "symmetrical" means that the compound has the same structure on both sides of the squarylium skeleton. That is, in general formula (1), L 1 and L 2 , R 1 and R 2 , m and n, and Ar 1 and Ar 2 However, when applying the compound to various applications, the compound according to the present invention may become asymmetric by modifying one of the structures on the left and right of the squarylium skeleton, but even in such cases, the compound according to the present invention can be suitably used.

[0045] In the present invention, Ar 1 and Ar2 is preferably, independently of each other, a hydrogen atom or a group represented by the general formula (2).

[0046] In the general formula (2), R 3 and R 4 each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent.

[0047] R 3 and R 4 Specific examples of the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by R 1 and R 2 are the same as those of the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by R

[0048] R 3 and R 4 Specific examples of the "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent" represented by R

[0049] R 3 and R 4 Specific examples of the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by R 1 and R 2Examples of the "aryl group having 6 to 36 carbon atoms which may have a substituent" represented by are the same as the "aryl group having 6 to 36 carbon atoms".

[0050] R 3 and R 4 Examples of the "aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent" represented by and and and as the "aromatic heterocyclic group having 5 to 36 ring-forming atoms" are the same as the R 1 and R 2 Examples of the "aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent" represented by are the same as the "aromatic heterocyclic group having 5 to 36 ring-forming atoms".

[0051] R 3 and R 4 Examples of the "substituent" in the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent", "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent", "aryl group having 6 to 36 carbon atoms which may have a substituent", or "aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent" represented by are the same as the "substituent" in the "linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent" etc. represented by and and and . 1 and L 2

[0052] R 3 and R 4 may be bonded to each other to form a ring. Specifically, R 3 and R 4 may be bonded to each other to form a ring by a single bond, a vinylene bond (—CH═CH—), or a bond through an oxygen atom, a sulfur atom, a selenium atom, or a nitrogen atom.

[0053] In the present invention, R 3 and R 4 ​is preferably a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent. Also, R 3 and R 4 When they are groups having a substituent, the "substituent" is preferably a linear or branched alkyl group having 1 to 19 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 19 carbon atoms, an amino group having 0 to 20 carbon atoms, or an amide group having 0 to 20 carbon atoms.

[0054] In General Formula (2), Z 1 represents an oxygen atom or a sulfur atom. Also, in General Formula (2), x and y each independently represent an integer of 0 or 1. That is, when x is 0, y is 0 or 1, and when x is 1, y is 0 or 1. In the present invention, it is preferable that x is 0 and y is 0, x is 0 and y is 1, or x is 1 and y is 0.

[0055] Specific examples of the squarylium compound represented by the above General Formula (1) are shown below, but the present invention is not limited to these compounds. Also, in the following exemplified compounds, hydrogen atoms, carbon atoms, etc. are partially omitted in the description. Further, the following exemplified compounds show an example of the possible isomers, and the squarylium compound according to the present invention shall include all other isomers. Also, the squarylium compound according to the present invention may be a mixture of two or more isomers. In the following exemplified compounds, the 2-ethylhexyl group is represented as R b1 and the n-hexyl group (-C6H 13 ) may be represented as R b2 .

[0056]

Chemical formula

[0057]

Chem.

[0058]

Chem.

[0059]

Chem.

[0060]

Chem.

[0061]

Chem.

[0062]

Chem.

[0063]

Chem.

[0064]

Chem.

[0065]

Chem.

[0066]

Chem.

[0067]

Chem.

[0068]

change

[0069]

change

[0070]

change

[0071]

change

[0072]

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[0073]

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[0074]

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[0075]

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[0076]

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[0077]

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[0078] [Chemistry]

[0079] [Chemistry]

[0080] [Chemistry]

[0081] [Chemistry]

[0082] [Chemistry]

[0083] [Chemistry]

[0084] [Chemistry]

[0085] The compound of the present invention represented by the general formula (1) can be synthesized by a known method. As an example, the synthesis method of compound (A-1) will be described. First, after brominating the following compound (1a) (4-(2-ethylhexyl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole) to obtain a brominated compound, a coupling reaction with an amine compound represented by the following compound (2a) is carried out to obtain the following compound (3a). Then, compound (A-1) can be synthesized by reacting compound (3a) with squaric acid. Note that compound (1a) can be synthesized by a known method.

[0086] [Chemistry]

[0087] The compound represented by the general formula (1) can be purified by column chromatography, recrystallization with a solvent, and reprecipitation, washing, etc. Also, the identification of the compound can be carried out by nuclear magnetic resonance analysis (NMR) and mass spectrometry.

[0088] In the compound represented by the general formula (1), the cation exists in a delocalized manner as follows.

[0089]

Chemical formula

[0090] <Near-infrared absorbing dye> Since the squarylium compound represented by the general formula (1) has absorption in the near-infrared light region and high heat resistance, it can be used as a near-infrared absorbing dye. That is, the near-infrared absorbing dye according to the present invention contains the squarylium compound represented by the general formula (1). As the near-infrared absorbing dye, the compound represented by the general formula (1) and a known near-infrared absorbing material can also be used in combination. Further, it can also be used for various applications as a near-infrared absorbing dye composition containing the compound represented by the general formula (1), a solvent, an additive, etc. Furthermore, the near-infrared absorbing dye can also be used as a near-infrared absorbing ink by dissolving or dispersing it in a solvent.

[0091] <Near-infrared absorbing material> The compound represented by the general formula (1) can be used as a near-infrared absorbing material for organic electrodevices, etc. Also, a near-infrared absorbing material composition obtained by dissolving or dispersing the compound in various media (the media may be a liquid such as an organic solvent or a solid such as a polymer material) can also be used for various applications. Further, a film may be formed from the compound or the composition, and the film may be used for the above applications.

[0092] The compound represented by the general formula (1) has solubility suitable for solution processes. In particular, it is also conceivable to use a composition containing the compound in a solution process to manufacture an organic electronic device. In this specification, the "solution process" refers to a process of easily producing a film, an element, etc. by applying a composition in the form of a solution, a dispersion, an emulsion, etc. in which a compound is dissolved or dispersed in an organic solvent or the like.

[0093] Note that the solubility of the compound can be evaluated by adding the compound to an organic solvent, stirring or applying it to an ultrasonic cleaner at room temperature (25 ± 5°C) for about 1 or 2 minutes, and then visually measuring the solubility (or saturated solubility). In the manufacturing process of elements or the like using a solution process, sufficient solubility is required, so it is preferable that the solubility is high.

[0094] <Thin film> A thin film can be produced using the near-infrared absorbing dye composition containing the squarylium compound represented by the general formula (1). That is, the thin film according to the present invention is a thin film using the compound represented by the general formula (1) and contains the compound.

[0095] When producing a thin film by applying a near-infrared absorbing dye composition in a solution process, the composition may contain additives, binder polymers, etc. It is also possible to dissolve or disperse only the above-mentioned compound or the above-mentioned compound and a binder polymer in a solvent to obtain a coating solution. Specific examples of the binder polymer include poly-N-vinylcarbazole, polyarylate, polystyrene, polyester, polysiloxane, polymethyl acrylate, polymethyl methacrylate, polyether, polycarbonate, polyamide, polyimide, polyamideimide, polyparaxylylene, polyethylene, polyethylene ether, polypropylene ether, polyphenylene oxide, polyethersulfone, polyaniline and its derivatives, polythiophene and its derivatives, polyphenylene vinylene and its derivatives, polyphenylene ethynylene and its derivatives, polyfluorene and its derivatives, and polythienylene vinylene and its derivatives, etc., organic or inorganic polymer compounds.

[0096] As methods for forming a thin film, generally, vapor phase methods such as resistance heating evaporation, electron beam evaporation, sputtering, and molecular layer deposition, which are vacuum processes; solution methods such as spin coating, drop casting, dip coating, and spraying; relief printing methods such as flexographic printing and resin letterpress printing, lithographic printing methods such as offset printing, dry offset printing, pad printing, gravure printing methods such as gravure printing, screen printing methods such as silk screen printing, stencil printing methods such as mimeograph printing and lithographic printing, printing methods such as inkjet printing and microcontact printing; and methods combining a plurality of these techniques, etc. can be mentioned.

[0097] The solvents used in film formation include aromatic organic solvents such as benzene, toluene, xylene, mesitylene, tetralin (1,2,3,4 - tetrahydronaphthalene), monochlorobenzene, o - dichlorobenzene, m - dichlorobenzene, p - dichlorobenzene, and nitrobenzene; halogenated alkyl organic solvents such as dichloromethane, chloroform, 1,2 - dichloroethane, 1,1,2 - trichloroethane, and dichloromethane; nitrile solvents such as benzonitrile and acetonitrile; ether solvents such as diethyl ether, tetrahydrofuran (THF), dioxane, diisopropyl ether, cyclopentyl methyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol monomethyl ether (PGME); ester solvents such as ethyl acetate, n - butyl acetate, and propylene glycol monomethyl ether acetate (PGMEA); alcohol solvents such as methanol, isopropanol, n - butanol, propylene glycol, 1,3 - butanediol, 1,4 - butanediol, 2,3 - butanediol, cyclohexanol, and 2 - n - butoxyethanol; ketones such as acetone and cyclohexanone; amides such as N,N - dimethylformamide (DMF) and N - methylpyrrolidone (NMP); dimethyl sulfoxide (DMSO); chloroform (trichloromethane), etc., but are not limited thereto. Further, the above solvents may be used alone or in a mixture of two or more, and the solvent to be used can be selected according to the structure of the compound.

[0098] The film thickness of the thin film varies depending on its use, but is usually preferably 1 nm to 50 μm, more preferably 5 nm to 20 μm, and even more preferably 10 nm to 10 μm.

[0099] <Organic Electronics Device> An organic electronic device can be fabricated using the compound represented by the general formula (1). Examples of the organic electronic device include photoelectric conversion elements such as solar cells and optical sensors, thin film transistors, and organic EL elements. Hereinafter, as an embodiment of the organic electronic device according to the present invention, attention is paid to a photoelectric conversion element that is particularly expected to be developed for near-infrared applications, and a photoelectric conversion element using the compound according to the present invention as a near-infrared absorption material will be described.

[0100] Although detailed description is omitted in this specification, near-infrared light with a wavelength exceeding 700 nm has high permeability to biological tissues. Therefore, it can also be used for observing in-vivo tissues, and can be applied in various modes according to the purpose in pathological elucidation and diagnosis in the medical field, such as near-infrared fluorescence probes.

[0101] [Photoelectric conversion element] A photoelectric conversion element is an element in which a photoelectric conversion section is disposed between a pair of opposing electrodes. Since the compound of the present invention represented by the general formula (1) has near-infrared absorption characteristics, it is expected to be used as a photoelectric conversion element and can be considered for use in the photoelectric conversion section of the photoelectric conversion element. The photoelectric conversion element can be used as an imaging element such as a solar cell, a near-infrared optical sensor, or a near-infrared image sensor.

[0102] Specifically, the compound represented by the general formula (1) can be used as a constituent material of the photoelectric conversion part of a photoelectric conversion element. The photoelectric conversion part often consists of a photoelectric conversion layer and one or more thin film layers other than the photoelectric conversion layer selected from the group consisting of an electron transport layer, a hole transport layer, an electron blocking layer, a hole blocking layer, and an interlayer contact improvement layer, etc. Since the compound of the present invention is useful as a light absorption material, a photoelectric conversion material, a charge transport material, etc., it can be considered for use in the thin film layers other than the above-mentioned photoelectric conversion layer, but it is preferably used as a thin film layer of the photoelectric conversion layer. In particular, when the compound of the present invention is used as a light absorption material, a photoelectric conversion material, etc. in an organic thin film solar cell, it can be expected to efficiently collect solar energy and utilize it for photoelectric conversion. The photoelectric conversion layer may be composed only of the compound represented by the general formula (1), or may be composed of the compound represented by the general formula (1) in addition to known light absorption materials and other additives, etc. Note that the photoelectric conversion layer may contain a plurality of the compounds represented by the general formula (1).

[0103] The material that can be used as the electrode of the photoelectric conversion element is not particularly limited as long as it has a certain degree of conductivity. However, it is preferably selected in consideration of the adhesion, electron affinity, ionization potential, and stability, etc. with the adjacent photoelectric conversion layer and other layers.

[0104] Specific examples of the conductive material used for the electrode include conductive transparent oxide semiconductors such as tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), and indium-tin composite oxide; metals such as gold, silver, platinum, chromium, aluminum, iron, cobalt, nickel, and tungsten; inorganic conductive substances such as copper iodide and copper sulfide; conductive polymers such as polythiophene, polypyrrole, and polyaniline; and carbon, etc. These materials may be used by mixing a plurality of them as necessary.

[0105] Among the electrodes, the conductive support, which is a transparent electrode film used for at least one side where light is incident, needs to have translucency that allows light contributing to photoelectric conversion to pass through. Also, since the conductive support is a member having the function of extracting current from the photoelectric conversion layer, it is preferably a conductive substrate. Examples of the material of the conductive support include ITO and FTO (fluorine-doped tin oxide).

[0106] Generally, an organic semiconductor film is used for the photoelectric conversion layer. The organic semiconductor film may be one layer or a plurality of layers. When it is one layer, a p-type organic semiconductor layer, an n-type organic semiconductor layer, or a mixed layer thereof is used. On the other hand, when it is a plurality of layers, it is about 2 to 10 layers, and has a structure in which any of a p-type organic semiconductor layer, an n-type organic semiconductor layer, or a mixed film layer thereof is laminated, and a buffer layer may be inserted between the layers. The compound of the present invention can be considered to be used as a p-type semiconductor material or an n-type semiconductor material.

[0107] <Near-infrared cut filter> Near-infrared absorbing materials are also used in near-infrared cut filters that utilize their property of selectively absorbing light in a specific wavelength range, plant growth regulating films, and the like. Since the compound of the present invention and the composition containing the compound have high near-infrared absorption ability and excellent heat resistance, they can be considered to be used as materials constituting near-infrared cut filters and the like. Specific applications of near-infrared cut filters include color filters used in semiconductors, electronic devices, various sensors, liquid crystal display devices, or imaging devices.

[0108] [Color filter] When the compound of the present invention represented by the general formula (1) is used as a near-infrared absorbing dye in a color filter, a method of forming two layers of a color filter layer and a near-infrared cut filter layer on a substrate, or a method of forming one layer having both the functions of a color filter and a near-infrared cut filter can be used. In the case of a single-layer configuration, a thin-film filter can be produced by using the layer as an optical filter layer.

[0109] When the optical filter layer has a single-layer structure, the colorant for the color filter includes a near-infrared absorbing dye composition containing at least one compound represented by the general formula (1), and other components generally used in the production of color filters. Examples of other components include dyes or pigments such as dyes, resin components, organic solvents, and additives such as photopolymerization initiators. Also, these components may be selected as appropriate, and other components may be added as necessary.

[0110] A general color filter can be obtained, for example, in the case of a method using a photolithography process, by applying a liquid prepared by mixing a dye or pigment such as a dye or pigment with a resin component and a solvent onto a substrate such as glass or resin, photopolymerizing it using a photomask, creating a colored pattern of a dye-resin composite film that is soluble / insoluble in the solvent, and heating it after washing. Also, in the electrodeposition method and the printing method, a colored pattern is created using a mixture of a dye and a resin or other components.

[0111] Examples of dyes or pigments in the colorant for the color filter include red pigments such as C.I. Pigment Red 177, 209, 242, 254, 255, 264, 269, C.I. Pigment Orange 38, 43, 71; other red lake pigments; yellow pigments such as C.I. Pigment Yellow 138, 139, 150; red dyes such as C.I. Acid Red 88, C.I. Basic Violet 10; basic dyes such as C.I. Basic Blue 3, 7, 9, 54, 65, 75, 77, 99, 129; acid dyes such as C.I. Acid Blue 9, 74; disperse dyes such as Disperse Blue 3, 7, 377; spiron dyes; cyanine-based, indigo-based, phthalocyanine-based, anthraquinone-based, methine-based, triarylmethane-based, indanthrene-based, oxazine-based, dioxazine-based, azo-based, xanthene-based; and other blue lake pigments, but are not particularly limited.

[0112] In the manufacturing process of a color filter and a colorant for a color filter, it is necessary to dissolve or disperse the compound of the present invention represented by the general formula (1) well in an organic solvent containing a resin or the like. Therefore, it is preferable that the compound has high solubility and dispersibility in the organic solvent. Although not particularly limited, specifically, the same solvent as that used in the film formation can be used as the organic solvent.

[0113] As the resin component in the colorant for a color filter, known resins can be used as long as they have the properties required in the manufacturing process and use of the resulting color filter resin film. Examples of the resin component include acrylic resin, polyolefin resin, styrene resin, polyimide resin, polyurethane resin, polyester resin, epoxy resin, vinyl ether resin, phenol (novolak) resin, other transparent resins, photocurable resins, or thermosetting resins. The monomer or oligomer components constituting these resins can be appropriately combined and used. In addition, a copolymer obtained by combining the monomers constituting these resins can also be used. In the case of a liquid colorant, the content of the resin component in the colorant for a color filter is preferably 5 to 95% by mass, more preferably 10 to 50% by mass, based on the mass of the colorant.

[0114] Also, additives such as surfactants, dispersants, defoamers, and leveling agents can be added according to the application. The amount of these additives used is preferably an appropriate amount, which preferably does not reduce the solubility or improve it more than necessary, and also does not affect the effects of other similar additives used in the manufacture of products such as color filters. The additives can be added at any timing in the process of preparing the colorant.

[0115] Examples of other additives other than the above additives in the colorant for color filters of the present invention include components necessary for polymerization and curing of resins, such as photopolymerization initiators and crosslinking agents, and surfactants and dispersants necessary for stabilizing the properties of components in the liquid colorant for color filters. Any of these can be known ones for manufacturing color filters and are not particularly limited. The total amount of additives used in the total solid content of the colorant for color filters is preferably 5 to 60% by mass, more preferably 10 to 40% by mass, based on the mass of the colorant.

Examples

[0116] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples. The identification of the compounds obtained in the examples was 1 performed using 1H-NMR (manufactured by JEOL Ltd., product name: JNM-ECZ400S / L1 type). In addition, for the obtained compounds, measurement of ultraviolet-visible-near-infrared (UV-VIS-NIR) absorption spectra was performed using LAMBDA750-UV / VIS / NIR-SPECTROMETAR (product name, manufactured by PerkinElmer Japan Co., Ltd.), and thermal analysis was performed using Thermoplus EVO2-TG-DTA8122 Smartloader (product name, manufactured by Rigaku Corporation).

[0117] [Example 1] 〈Synthesis of Compound (A-1)〉 To a reaction vessel were added 3,3'-dibromo-2,2'-bithiophene (2.0 g, 6.17 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), sodium t-butoxide (1.3 g, 13.6 mmol, manufactured by Kanto Chemical Co., Inc.), and dehydrated toluene (100 mL), and degassing and argon substitution were performed. To the above reaction vessel, under an argon stream, tris(dibenzylideneacetone)dipalladium(0) (283 mg, 0.309 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) and 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (769 mg, 1.23 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and finally 2-ethylhexylamine (1.00 mL, 6.17 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 103 °C for 6 hours and 5 minutes to carry out the reaction. After cooling to room temperature, the reaction solution was filtered through Celite, and the solvent in the filtrate was distilled off under reduced pressure. Purification was performed by silica gel column chromatography (SiO2 / hexane:ethyl acetate (20:1)) to obtain the following compound (3) as a yellow oily compound (yield: 1.97 g, yield: 100%).

[0118] 〈NMR analysis results〉 1 1H-NMR (400 MHz, CDCl3): δ (ppm) = 0.86 - 0.92 (m, 6H), 1.28 - 1.33 (m, 8H), 1.95 (m, 1H), 4.06 (d, 2H), 6.99 (d, 2H), 7.12 (d, 2H)

[0119] Under an argon stream, the following compound (3) (100.0 mg, 0.343 mmol) and 3 mL of tetrahydrofuran were added to a reaction vessel, and while stirring under ice cooling, N-bromosuccinimide (61.1 mg, 0.343 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to conduct the reaction. After stopping the reaction, extraction was performed with ethyl acetate, followed by washing three times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out, and toluene was added without completely distilling off the solvent. Subsequently, sodium t-butoxide (49.5 mg, 0.515 mmol, manufactured by Kanto Chemical Co., Inc.) was added, and degassing and argon substitution were performed. Under an argon stream, tris(dibenzylideneacetone)dipalladium(0) (15.7 mg, 0.017 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), and tri-t-butylphosphine (33 mass% xylene solution) (42.1 mg, 0.069 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were added, and finally di(4-methylphenyl)amine (67.7 mg, 0.343 mmol) was added, and the reaction was conducted by stirring at 92 °C for 4 hours and 55 minutes. After cooling to room temperature, the reaction solution was filtered through celite, and the solvent in the filtrate was distilled off under reduced pressure. Purification was performed by silica gel column chromatography (SiO2 / hexane:toluene (8:1)) to obtain a fluorescent yellow-green oily compound (4) (yield: 64.1 mg, yield: 38%).

[0120] Under an argon stream, compound (4) (64 mg, 0.131 mmol), squaric acid (7.5 mg, 0.066 mmol, manufactured by Sigma-Aldrich Co. LLC), and 6 mL of n-butanol:toluene (1:1) were added to a reaction vessel, and heating and stirring were performed at 95 - 97 °C for 4 hours and 45 minutes. After cooling to room temperature, the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (70 °C) were performed to obtain the following compound (A-1) (blue-violet solid, yield: 27.2 mg).

[0121] 〈NMR analysis results〉 11H-NMR (400 MHz, CDCl3): δ (ppm) = 0.83 - 0.88 (m, 12H), 1.23 - 1.43 (m, 16H), 2.36 (m, 12H), 1.90 (m, 2H), 3.89 (d, 4H), 6.21 (s, 2H), 7.16 (d, 16H), 7.74 (s, 2H)

[0122] [Chemical formula]

[0123] 〈Absorption spectrum measurement〉 A dimethyl sulfoxide solution (concentration 1.0×10 -5 mol / L) of the obtained compound (A-1) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was carried out. The obtained absorption spectrum is shown in Figure 1. Also, the absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) values determined based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0124] 〈Thermal analysis〉 The decomposition temperature (5% weight loss temperature) of the obtained compound (A-1) was measured. The measurement results are shown in Table 2.

[0125] [Example 2] 〈Synthesis of compound (A-3)〉 The above compound (3) (668.5 mg, 2.29 mmol) and 10.0 mL of tetrahydrofuran were added to a reaction vessel, and while stirring under an argon stream and ice-cooling, N-bromosuccinimide (408.2 mg, 2.29 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to conduct the reaction. After stopping the reaction, extraction was performed with ethyl acetate, followed by washing three times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:toluene (20:1)). To the obtained fraction, 5.0 mL of dehydrated toluene and sodium t-butoxide (130.8 mg, 1.36 mmol, manufactured by Kanto Chemical Co., Inc.) were added, and vacuum degassing and argon substitution were performed. Under an argon stream, tris(dibenzylideneacetone)dipalladium(0) (207.7 mg, 0.227 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), and tri-t-butylphosphine (33 mass% xylene solution) (1.0 mL, 0.567 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were added, and finally, di(4-methoxyphenyl)amine (260.0 mg, 1.13 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added. After stirring at 88 °C for 1 hour and 30 minutes, it was cooled to room temperature, and the reaction solution was filtered through Celite. After distilling off the solvent in the filtrate under reduced pressure, purification was performed by silica gel column chromatography (SiO2 / hexane:ethyl acetate (10:1)) to obtain the following compound (5) (yield: 334.4 mg, yield: 28%).

[0126] 〈NMR analysis results〉 1 1H-NMR (400 MHz, CDCl3): δ (ppm) = 0.82 - 0.89 (m, 6H), 1.20 - 1.35 (m, 8H), 1.88 (m, 1H), 3.79 (s, 6H), 3.95 (m, 2H), 6.61 (s, 1H), 6.81 (d, 4H), 6.94 (d, 1H), 7.03 (d, 1H), 7.10 (d, 4H)

[0127] Under an argon stream, the above compound (5) (344.4 mg, 0.645 mmol), squaric acid (35.0 mg, 0.307 mmol, manufactured by Sigma - Aldrich Co., LLC), and 16 mL of n - butanol:toluene (1:1) were added to the reaction vessel, and the mixture was heated and stirred at 99 °C for 1 hour and 10 minutes. After the raw materials disappeared, the mixture was cooled to room temperature, and the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75 °C) were carried out to obtain the following compound (A - 3) (reddish - purple solid, yield: 232.3 mg, yield rate: 68%).

[0128]

Chemical formula

[0129] 〈NMR analysis results〉 1 H - NMR (400 MHz, THF - d8): δ (ppm) = 0.82 - 0.88 (m, 12H), 1.20 - 1.36 (m, 16H), 1.88 (m, 2H), 3.75 (s, 12H), 4.02 (d, 4H), 6.20 (s, 2H), 6.87 (d, 8H), 7.23 (d, 8H), 7.71 (s, 2H)

[0130] 〈Absorption spectrum measurement〉 A dimethyl sulfoxide solution (concentration 2.3×10 -5 mol / L) of the obtained compound (A - 3) was prepared, and ultraviolet - visible - near - infrared absorption spectrum measurement was carried out. The absorption maximum wavelength (nm) and molar extinction coefficient (M -1 cm -1 ) values obtained based on the results of the ultraviolet - visible - near - infrared absorption spectrum measurement are shown in Table 1.

[0131] 〈Thermal analysis〉 The decomposition temperature (5% weight loss temperature) of the obtained compound (A - 3) was measured. The measurement results are shown in Table 2.

[0132] 〈Solubility evaluation〉 The obtained compound (A-3) was weighed into a transparent sample tube, and chloroform was added to prepare a 5 mass% solution. The prepared solution was sonicated for 1 minute at room temperature (25 ± 2 °C) in an ultrasonic cleaner, and then the solubility evaluation was carried out by visually checking for the presence of undissolved residue. The results are shown in Table 3. The criteria for judgment are as follows. Completely dissolved: ○ Remaining turbidity: △ Not dissolved: ×

[0133] [Example 3] 〈Synthesis of Compound (A-10)〉 The above compound (3) (326.1 mg, 1.12 mmol) and 6.0 mL of tetrahydrofuran were added to a reaction vessel, and while stirring under an argon stream and ice cooling, N-bromosuccinimide (199.1 mg, 1.12 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to carry out the reaction. After stopping the reaction, extraction was carried out with ethyl acetate, followed by washing 3 times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:toluene (15:1)). 5 mL of dehydrated toluene and sodium t-butoxide (39.0 mg, 0.41 mmol, manufactured by Kanto Chemical Co., Inc.) were added to the obtained fraction, and vacuum degassing and argon substitution were carried out. Under an argon stream, tris(dibenzylideneacetone)dipalladium(0) (12.3 mg, 0.014 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), and tri-t-butylphosphine (33 mass% xylene solution) (50.8 mg, 0.083 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were added, and finally di-2-ethylhexylamine (100 mg, 0.27 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added. After stirring at 88 °C for 3 hours and 30 minutes, it was cooled to room temperature, and the reaction solution was filtered through celite. After distilling off the solvent in the filtrate under reduced pressure, purification by silica gel column chromatography (SiO2 / hexane:toluene (15:1)) was carried out to obtain the following compound (6) (yield: 42.0 mg, yield: 7%).

[0134] Under an argon stream, the above compound (6) (40.0 mg, 0.075 mmol), squaric acid (4.3 mg, 0.038 mmol, manufactured by Sigma-Aldrich Co., LLC), and 6 mL of n-butanol:toluene (1:1) were added to a reaction vessel, and the mixture was heated and stirred at 99 °C for 2 hours and 15 minutes. After the raw materials disappeared, the mixture was cooled to room temperature, and the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75 °C) were performed to obtain the following compound (A-10) (black-purple solid, yield: 17.6 mg, yield rate: 41%). The structure of compound (A-10) was confirmed by NMR.

[0135] [Chemical formula]

[0136] 〈Measurement of absorption spectrum〉 A dimethyl sulfoxide solution (concentration 1.0×10 -5 mol / L) of the obtained compound (A-10) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) values obtained based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0137] 〈Thermal analysis〉 The decomposition temperature (5% weight loss temperature) of the obtained compound (A-10) was measured. The measurement results are shown in Table 2.

[0138] [Example 4] 〈Synthesis of compound (A-17)〉 To the reaction vessel, the above compound (3) (500.0 mg, 1.72 mmol) and 15.0 mL of tetrahydrofuran were added. While stirring under an argon stream and in ice-cooling, N-bromosuccinimide (305.3 mg, 1.72 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the reaction was carried out. After stopping the reaction using 30 mL of water, extraction was performed with 20 mL of ethyl acetate, followed by washing three times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:chloroform (20:1)) to obtain a fraction containing the monobromo compound. To a 50 mL corvette, the obtained monobromo compound, 5 mL of dehydrated toluene, and sodium t-butoxide (38.9 mg, 0.405 mmol, manufactured by Kanto Chemical Co., Inc.) were added, and vacuum degassing and argon substitution were performed. Under an argon stream, tris(dibenzylideneacetone)dipalladium(0) (12.4 mg, 0.014 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), and tri-t-butylphosphine (33 mass% xylene solution) (33.1 mg, 0.054 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were added, and finally carbazole (45.1 mg, 0.270 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added. After stirring at 92 °C for 1 hour and 50 minutes, it was cooled to room temperature, and the reaction solution was filtered through celite. After distilling off the solvent in the filtrate under reduced pressure, purification by silica gel column chromatography (SiO2 / hexane:toluene (15:1)) was performed to obtain the following compound (7) (yield: 81.1 mg, yield: 35%).

[0139] 〈1H-NMR analysis results〉 〈 1 1H-NMR (400 MHz, CDCl3): δ (ppm) = 0.85 - 0.94 (m, 6H), 1.27 - 1.38 (m, 8H), 1.95 (m, 1H), 4.12 (d, 2H), 7.05 (d, 1H), 7.19 (s, 1H), 7.21 (d, 1H), 7.32 (t, 2H), 7.44 (t, 2H), 7.50 (d, 2H), 8.11 (d, 2H)

[0140] Under an argon stream, the above compound (7) (45.0 mg, 0.10 mmol), squaric acid (5.6 mg, 0.050 mmol, manufactured by Sigma-Aldrich Co., LLC), and 6 mL of n-butanol:toluene (1:1) were added to a reaction vessel, and the mixture was heated and stirred at 99 °C for 3 hours. After the raw materials disappeared, the mixture was cooled to room temperature, and the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75 °C) were performed to obtain the following compound (A-17) (black solid, yield: 17.9 mg, yield: 37%). The structure of compound (A-17) was confirmed by NMR.

[0141] [Chemical formula]

[0142] 〈Measurement of absorption spectrum〉 A dimethyl sulfoxide solution (concentration 1.0×10 -5 mol / L) of the obtained compound (A-17) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) values obtained based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0143] 〈Thermal analysis〉 The decomposition temperature (5% weight loss temperature) of the obtained compound (A-17) was measured. The measurement results are shown in Table 2.

[0144] [Example 5] 〈Synthesis of compound (A-19)〉 The above compound (3) (148.8 mg, 0.51 mmol) and 4.0 mL of tetrahydrofuran were added to a reaction vessel, and while stirring under an argon stream and ice-cooling, N-bromosuccinimide (90.9 mg, 0.51 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to conduct the reaction. After the reaction was stopped, extraction was performed with ethyl acetate, followed by washing three times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:chloroform (15:1)). To the obtained fraction, 5 mL of dehydrated toluene and sodium t-butoxide (23.4 mg, 0.24 mmol, manufactured by Kanto Chemical Co., Inc.) were added, and vacuum degassing and argon substitution were performed. Under an argon stream, tris(dibenzylideneacetone)dipalladium(0) (7.4 mg, 0.008 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), and tri-t-butylphosphine (33 mass% xylene solution) (19.9 mg, 0.032 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were added, and finally, iminostilbene (31.3 mg, 0.16 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added. After stirring at 97 °C for 1 hour and 55 minutes, it was cooled to room temperature, and the reaction solution was filtered through celite. After distilling off the solvent in the filtrate under reduced pressure, purification by silica gel column chromatography (SiO2 / hexane:toluene (15:1)) was performed to obtain the following compound (8) (yield: 45.8 mg, yield: 21%).

[0145] Under an argon stream, the above compound (8) (30.0 mg, 0.062 mmol), squaric acid (2.4 mg, 0.021 mmol, manufactured by Sigma-Aldrich Co. LLC), and 6 mL of n-butanol:toluene (1:1) were added to a reaction vessel, and heated and stirred at 99 °C for 3 hours. After the raw materials disappeared, it was cooled to room temperature, and the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75 °C) were performed to obtain the following compound (A-19) (black solid, yield: 4.3 mg, yield: 7%). The structure of compound (A-19) was confirmed by NMR.

[0146] [Chemical formula]

[0147] 〈Absorption spectrum measurement〉 An N-methylpyrrolidone solution (concentration: 1.0×10 -5 mol / L) of the obtained compound (A-19) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) obtained based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0148] [Example 6] 〈Synthesis of compound (A-21)〉 To a reaction vessel were added the above compound (3) (298.8 mg, 1.03 mmol) and 4.0 mL of tetrahydrofuran. While stirring under an argon stream and ice-cooling, N-bromosuccinimide (182.4 mg, 1.03 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the reaction was carried out. After stopping the reaction with water, extraction was performed with ethyl acetate, followed by washing three times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:toluene (20:1)) to obtain a fraction containing the monobromo product. To a 50 mL corvette were added the obtained monobromo product, 5 mL of dimethylformamide, and 2 M aqueous potassium carbonate solution (2.0 mL), and vacuum degassing and argon substitution were performed. Under an argon stream, tetrakis(triphenylphosphine)palladium(0) (15.6 mg, 0.014 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and finally dimethoxytriphenylamine tetramethyldioxaborane (139.8 mg, 0.324 mmol) was added. After stirring at 79 °C for 1 hour and 20 minutes, it was cooled to room temperature, and the reaction was stopped with water. After extraction with ethyl acetate, washing three times with water and once with brine, and drying using magnesium sulfate, filtration and distillation under reduced pressure were carried out, followed by purification by silica gel column chromatography (SiO2 / hexane:ethyl acetate (8:1)) to obtain the following compound (9) (yield: 177.8 mg, yield: 29%).

[0149] 〈NMR Analysis Results〉 1 1H-NMR (400 MHz, CDCl3): δ (ppm) = 0.86 - 0.92 (m, 6H), 1.24 - 1.29 (m, 8H), 1.95 (m, 1H), 3.80 (s, 6H), 4.05 (m, 2H), 6.84 (d, 4H), 6.94 (d, 2H), 7.00 (s, 1H), 7.09 (m, 6H), 7.44 (d, 2H)

[0150] Under an argon stream, the above compound (9) (177.8 mg, 0.30 mmol), squaric acid (17.0 mg, 0.15 mmol, manufactured by Sigma-Aldrich Co., LLC), and 6 mL of n-butanol:toluene (1:1) were added to a reaction vessel, and the mixture was heated and stirred at 97 °C for 2 hours and 35 minutes. After the disappearance of the raw materials, the mixture was cooled to room temperature, and the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75 °C) were performed to obtain the following compound (A-21) (reddish-purple solid, yield: 138.0 mg, yield: 73%). The structure of compound (A-21) was confirmed by NMR.

[0151]

Chemical Structure

[0152] 〈Absorption Spectrum Measurement〉 A dimethyl sulfoxide solution (concentration 2.0×10 -6 mol / L) of the obtained compound (A-21) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) values determined based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0153] 〈Thermal Analysis〉 The decomposition temperature (5% weight loss temperature) of the obtained compound (A-21) was measured. The measurement results are shown in Table 2.

[0154] 〈Solubility Evaluation〉 The solubility evaluation was carried out in the same manner as in Example 2, except that compound (A-21) was used instead of compound (A-3). The results are shown in Table 3.

[0155] [Example 7] 〈Synthesis of Compound (A-29)〉 To a reaction vessel were added the above compound (3) (200 mg, 0.69 mmol) and 3.0 mL of tetrahydrofuran, and while stirring under an argon stream and in ice-cooling, N-bromosuccinimide (116.0 mg, 0.65 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added. After stopping the reaction with water, extraction was performed with ethyl acetate, followed by washing 3 times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:toluene (20:1)) to obtain a fraction containing the monobromo product. To a 50 mL corvette were added the obtained monobromo product, 5 mL of dehydrated toluene, and sodium t-butoxide (27.2 mg, 0.28 mmol, manufactured by Kanto Chemical Co., Inc.), and vacuum degassing and argon substitution were performed. Under an argon stream, tris(dibenzylideneacetone)dipalladium(0) (8.7 mg, 0.010 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), and tri-t-butylphosphine (33 mass% xylene solution, manufactured by Fujifilm Wako Pure Chemical Corporation) (23.2 mg, 0.038 mmol) were added, and the mixture was stirred at 84 °C for 4 hours and 30 minutes. After cooling to room temperature, the reaction solution was filtered through celite. After distilling off the solvent in the filtrate under reduced pressure, purification by silica gel column chromatography (SiO2 / hexane:toluene (15:1)) was performed to obtain the following compound (10) (yield: 40.0 mg, yield: 20%).

[0156] 〈NMR Analysis Results〉 1 1H-NMR (400 MHz, CDCl3): δ (ppm) = 0.88 - 0.93 (m, 12H), 1.30 - 1.36 (m, 16H), 1.97 (m, 2H), 4.06 (d, 4H), 6.97 (d, 2H), 7.06 (s, 2H), 7.12 (d, 2H)

[0157] Under an argon stream, the following compound (10) (40.0 mg, 0.11 mmol), squaric acid (6.3 mg, 0.056 mmol, manufactured by Sigma-Aldrich Co., LLC), and 6 mL of n-butanol:toluene (1:1) were added to a reaction vessel, and the mixture was heated and stirred at 99 °C for 3 hours. After the raw materials disappeared, the mixture was cooled to room temperature, and the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75 °C) were performed to obtain the following compound (A-29) (black-purple solid, yield: 7.1 mg, yield rate: 16%).

[0158] [Chemical formula]

[0159] 〈NMR analysis results〉 1 1H-NMR (400 MHz, THF-d8): δ (ppm) = 0.80 - 1.00 (m, 24H), 1.21 - 1.48 (m, 32H), 2.01 (m, 4H), 4.16 (d, 8H), 7.03 (d, 2H), 7.11 (s, 2H), 7.23 (s, 2H), 7.34 (s, 2H), 7.91 (d, 2H)

[0160] 〈Absorption spectrum measurement〉 A dimethyl sulfoxide solution (concentration 1.2×10 -5 mol / L) of the obtained compound (A-29) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The values of the absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) obtained based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0161] [Example 8] 〈Synthesis of compound (A-53)〉 Referring to Example 1, the following compound (11) was obtained by performing the reaction in the same manner using aniline (manufactured by Kishida Chemical Co., Ltd.) instead of 2-ethylhexylamine. Subsequently, referring to Example 4, the following compound (12) was obtained by performing the same reaction.

[0162] The above compound (12) (110 mg, 0.263 mmol) and 10 mL of tetrahydrofuran were added to a reaction vessel, and while stirring under an argon stream and ice cooling, N-bromosuccinimide (46.9 mg, 0.263 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to conduct the reaction. After stopping the reaction with water, extraction was performed with ethyl acetate, followed by washing three times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:toluene (8:1)) to obtain a fraction containing the monobromo compound. To a 50 mL corvette, the obtained monobromo compound, 6 mL of dimethylformamide, and 2 mL of a 2M aqueous potassium carbonate solution were added, and vacuum degassing and argon substitution were performed. Under an argon stream, tetrakis(triphenylphosphine)palladium(0) (15.2 mg, 0.013 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and finally 1-(tert-butoxycarbonyl)-2-pyrroleboronic acid (55.6 mg, 0.263 mmol) was added. After stirring at 81 °C for 5 hours and 50 minutes, an aqueous potassium hydroxide solution was added. After stopping the reaction, filtration through celite was performed, and the filtrate was extracted with ethyl acetate, followed by washing three times with water and once with brine, and drying using magnesium sulfate. Filtration and distillation under reduced pressure were carried out, and purification by silica gel column chromatography (SiO2 / hexane:ethyl acetate (5:1)) was performed to obtain the following compound (13) (yield: 81.8 mg, yield: 64%).

[0163] [Chemical Structure]

[0164] 〈NMR Analysis Results〉 1 1H-NMR (400 MHz, CDCl3): δ (ppm) = 6.31 (m, 1H), 6.50 (m, 1H), 6.85 (m, 1H), 7.18 (s, 1H), 7.33 (m, 4H), 7.45 (t, 2H), 7.54 (m, 4H), 7.64 (d, 2H), 8.11 (d, 2H), 8.36 (s, 1H)

[0165] Under an argon stream, the above compound (13) (81.8 mg, 0.168 mmol), squaric acid (9.6 mg, 0.084 mmol, manufactured by Sigma-Aldrich Co., LLC), and 6 mL of n-butanol:toluene (1:1) were added to the reaction vessel, and the mixture was heated and stirred at 99 °C for 1 hour and 30 minutes. After the disappearance of the raw materials, the mixture was cooled to room temperature, and the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75 °C) were performed to obtain the following compound (A-53) (brown solid, yield: 75.5 mg, yield: 85%).

[0166] [Chemical formula]

[0167] 〈NMR analysis results〉 1 1H-NMR (400 MHz, DMSO-d8): δ (ppm) = 7.01 (d, 2H), 7.32 (m, 4H), 7.40 - 7.49 (m, 6H), 7.51 (d, 2H), 7.58 (d, 4H), 7.65 (m, 4H), 7.71 (s, 2H), 7.77 (d, 4H), 8.21 (d, 4H), 8.44 (s, 2H)

[0168] 〈Absorption spectrum measurement〉 A dimethyl sulfoxide solution (concentration 0.5×10 -5 mol / L) of the obtained compound (A-53) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) values determined based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0169] 〈Thermal analysis〉 The decomposition temperature (5% weight loss temperature) of the obtained compound (A-53) was measured. The measurement results are shown in Table 2.

[0170] [Example 9] 〈Synthesis of compound (A-57)〉 The above compound (3) (458 mg, 1.57 mmol) and 8.0 mL of tetrahydrofuran were added to a reaction vessel, and N-bromosuccinimide (279 mg, 1.57 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added while stirring under an argon stream and ice-cooling. After stopping the reaction with water, the mixture was extracted with ethyl acetate, washed three times with water and once with brine, and dried over magnesium sulfate. Filtration and evaporation under reduced pressure were performed to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:toluene (20:1)) to obtain a fraction containing the monobromo compound. To a 50 mL corvette were added the obtained monobromo compound, 10 mL of dimethylformamide, and 2.0 mL of a 2M aqueous potassium carbonate solution, followed by vacuum degassing and argon replacement. Under an argon stream, tetrakis(triphenylphosphine)palladium(0) (91 mg, 0.078 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and finally triphenylamine-4-boronic acid (453 mg, 1.57 mmol) was added. After stirring at 82 °C for 3 hours, the mixture was cooled to room temperature and the reaction was stopped with water. After extraction with ethyl acetate, it was washed three times with water and once with brine, and dried over magnesium sulfate. Filtration and evaporation under reduced pressure were performed, and purification by silica gel column chromatography (SiO2 / hexane:toluene (5:1)) was carried out to obtain the following compound (14) (yield: 674 mg, yield: 81%).

[0171] 〈NMR analysis results〉 1 1H-NMR (600 MHz, THF-d8): δ (ppm) = 0.85 - 0.92 (m, 6H), 1.26 - 1.39 (m, 8H), 1.94 (m, 1H), 4.15 (d, 2H), 6.99 (d, 2H), 7.03 (d, 2H), 7.05 (d, 1H), 7.07 - 7.08 (m, 4H), 7.16 (d, 1H), 7.22 - 7.25 (m, 4H), 7.34 (s, 1H), 7.53 (d, 2H)

[0172] Under an argon atmosphere, compound (14) (270 mg, 0.51 mmol), squaric acid (29 mg, 0.25 mmol, Sigma-Aldrich Co. LLC), and 15 mL of n-butanol:toluene (1:2) were added to a reaction vessel and stirred at 99°C for 2 hours and 15 minutes. After the raw materials had disappeared, the mixture was cooled to room temperature and the solvent was evaporated under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75°C) were performed to obtain the following compound (A-57) (purple solid, yield: 233 mg, 81%). The structure of compound (A-57) was confirmed by NMR.

[0173] [ka]

[0174] <Absorption spectrum measurement> The obtained compound (A-57) was dissolved in dimethyl sulfoxide (concentration 1.0 × 10 -5 The maximum absorption wavelength (nm) and molar extinction coefficient (M -1 cm -1 ) values are shown in Table 1.

[0175] <Thermal analysis> The decomposition temperature (5% weight loss temperature) of the obtained compound (A-57) was measured, and the measurement results are shown in Table 2.

[0176] [Example 10] Synthesis of Compound (A-58) The above compound (3) (708 mg, 2.43 mmol) and 10.0 mL of tetrahydrofuran were added to a reaction vessel, and N-bromosuccinimide (432 mg, 2.43 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added while stirring under an argon stream and ice cooling. After the reaction was stopped, it was extracted with ethyl acetate, washed three times with water and once with brine, and dried using magnesium sulfate. Filtration and evaporation under reduced pressure were performed to obtain a yellowish-brown oily crude product. The obtained crude product was purified by silica gel column chromatography (SiO2 / hexane:toluene (20:1)). 25 mL of dehydrated toluene and sodium t-butoxide (304 mg, 3.16 mmol, manufactured by Kanto Chemical Co., Inc.) were added to the obtained fraction, and vacuum degassing and argon substitution were performed. Under an argon stream, tris(dibenzylideneacetone)dipalladium(0) (111 mg, 0.12 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), and tri-t-butylphosphine (33 mass% xylene solution) (0.4 mL, 0.496 mmol, manufactured by Fujifilm Wako Pure Chemical Corporation) were added, and finally bis(4-dimethylaminophenyl)amine (621 mg, 2.43 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added. After stirring at 98 °C for 1 hour and 10 minutes, it was cooled to room temperature, and the reaction solution was filtered through Celite. After evaporating the solvent in the filtrate under reduced pressure, purification by silica gel column chromatography (SiO2 / hexane:ethyl acetate (4:1)) was performed to obtain the following compound (15) (yield: 422 mg, yield: 32%).

[0177] 〈NMR analysis results〉 1 1H-NMR (600 MHz, THF-d8): δ (ppm) = 0.82 - 0.90 (m, 6H), 1.18 - 1.34 (m, 8H), 1.93 (s, 1H), 2.87 (d, 12H), 4.00 (d, 2H), 6.54 (s, 1H), 6.63 (d, 4H), 6.99 (q, 6H)

[0178] Under an argon stream, the above compound (15) (420 mg, 0.771 mmol), squaric acid (44 mg, 0.385 mmol, manufactured by Sigma-Aldrich Co., LLC), and 20 mL of n-butanol:toluene (3:2) were added to the reaction vessel, and the mixture was heated and stirred at 99 °C for 3 hours. After the raw materials disappeared, the mixture was cooled to room temperature, and the solvent was distilled off under reduced pressure. After ultrasonic cleaning with methanol, filtration and vacuum drying (75 °C) were performed to obtain the following compound (A-58) (black solid, yield: 168 mg, yield: 47%).

[0179] [Chemical formula]

[0180] 〈NMR analysis results〉 1 1H-NMR (400 MHz, CDCl3): δ (ppm) = 0.84 - 0.86 (m, 12H), 1.25 (m, 16H), 1.88 (d, 2H), 2.96 (s, 24H), 3.85 (d, 4H), 5.95 (s, 2H), 6.66 - 6.68 (d, 8H), 7.16 - 7.18 (d, 8H), 7.61 (s, 2H)

[0181] 〈Measurement of absorption spectrum〉 A dimethyl sulfoxide solution (concentration 4.8×10 -6 mol / L) of the obtained compound (A-58) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The absorption maximum wavelength (nm) and molar extinction coefficient (M -1 cm -1 ) values obtained based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0182] 〈Thermal analysis〉 The decomposition temperature (5% weight loss temperature) of the obtained compound (A-58) was measured. The measurement results are shown in Table 2.

[0183] 〈Solubility evaluation〉 Solubility evaluation was performed in the same manner as in Example 2, except that compound (A-58) was used instead of compound (A-3). The results are shown in Table 3.

[0184] [Comparative Example 1] 〈Measurement of Absorption Spectrum〉 As a comparative compound, the following compound (B-1) described in Patent Document 2 was synthesized, and a dimethyl sulfoxide solution (concentration: 1.4×10 -5 mol / L) of the compound was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) obtained based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0185] [Chemical formula]

[0186] [Comparative Example 2] 〈Measurement of Absorption Spectrum〉 As a comparative compound (compound (B-2)), a commercially available near-infrared absorbing dye (trade name: IR813 / p-Toluenesulfonate, manufactured by Tokyo Chemical Industry Co., Ltd.) was prepared. A dimethyl sulfoxide solution (concentration: 1.0×10 -5 mol / L) of the compound (B-2) was prepared, and ultraviolet-visible-near-infrared absorption spectrum measurement was performed. The absorption maximum wavelength (nm) and molar absorption coefficient (M -1 cm -1 ) obtained based on the results of the ultraviolet-visible-near-infrared absorption spectrum measurement are shown in Table 1.

[0187] 〈Thermal Analysis〉 The decomposition temperature (5% weight loss temperature) of the compound (B-2) was measured. The measurement results are shown in Table 2.

[0188]

Table 1

[0189] As shown in Table 1, the compounds according to the present invention obtained in Examples 1 to 10 have a higher molar extinction coefficient in the near-infrared region with a longer wavelength compared to the compounds according to the Comparative Examples, and it is clear that they can efficiently absorb near-infrared light. Thus, by using the compounds according to the present invention that can efficiently absorb near-infrared light, for example, in the production of photoelectric conversion elements, etc., it is expected to produce elements that exhibit high conversion efficiency at low concentrations, and cost reduction becomes possible. Also, as shown in FIG. 1, it was found that the compounds according to the present invention have relatively little absorption in the visible light region.

[0190]

Table 2

[0191] As shown in Table 2, the compounds according to the present invention have high thermal durability compared to the compound (B-2) according to the Comparative Example. According to the compounds according to the present invention having such high heat resistance, improvement in the durability of photoelectric conversion elements and near-infrared absorption thin films can be expected. Note that the heat resistance evaluation of color filters is generally performed by observing the presence or absence of a hue change at a temperature of 200 °C or higher. Since all of the compounds according to the present invention have a decomposition temperature of 250 °C or higher, they can be expected to be suitably used as constituent materials for color filters.

[0192]

Table 3

[0193] As shown in Table 3, since the compounds according to the present invention have good solubility in organic solvents, their use as coating solutions in which the compounds are dissolved or dispersed in solvents can also be expected.

Industrial Applicability

[0194] The compound of the present invention has absorption in the near-infrared region and has high heat resistance. As a near-infrared absorbing dye, it is expected to be applied in the field of photoelectric conversion elements such as solar cells and near-infrared light sensors, and further in a wide range of fields such as NeuralDensity (ND) filters, the security field, agricultural films, dimming filters (heat shielding / semiconductor sensors), and photodynamic therapy, etc.

Claims

1. A squarylium compound represented by the following general formula (1): 【Chemical Formula 1】 where L １ and L ２ are each independently A single bond, A linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent, A divalent aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or A divalent aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, R １ and R ２ are each independently A linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, A linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent, A linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent, A cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, Aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or Aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, Ar １ and Ar ２ are each independently A hydrogen atom, An amino group having 6 to 36 carbon atoms which may have a substituent, Aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or Aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, m and n each independently represent an integer of 1 or 2.

2. In the general formula (1), Ar １ and Ar ２ each independently represents a hydrogen atom or a group represented by the following general formula (2). The squarylium compound according to claim 1: 【Chemical 2】 wherein, R ３ and R ４ are each independently A linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, A cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, Aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or Aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent, R ３ and R ４ may be joined to each other to form a ring, Z １ represents an oxygen atom or a sulfur atom, x and y each independently represent an integer of 0 or 1.

3. In the general formula (1), R １ and R ２ are each independently a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an aromatic heterocyclic group having 5 to 36 ring-forming atoms which may have a substituent. The squarylium compound according to claim 1.

4. A near-infrared absorbing dye containing the squarylium compound according to any one of Claims 1 to 3.

5. A thin film containing the squarylium compound according to any one of Claims 1 to 3.

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