JP2018168335A - Squarylium compound - Google Patents

Abstract

To provide a squarylium compound that shows a sharp absorption peak in the red to near-infrared regions.SOLUTION: A squarylium compound is represented by the formula (1). [In formula (1), Rand Rare coupled to each other, R, R, Rand Rindependently represent a hydrogen atom, an organic group or a polar functional group, ring A and ring B independently represent an optionally substituted, 6 membered or more, nonaromatic hydrocarbon ring, or an optionally substituted, 6 membered or more, nonheteroaromatic ring].SELECTED DRAWING: Figure 1

Description

  The present invention relates to a squarylium compound, a resin composition containing the compound, and an optical filter or sensor containing the resin composition.

  The squarylium compound is useful as a dye having an absorption range in the red to near infrared region, and various types of squarylium compounds have been known so far. For example, Patent Documents 1 and 2 disclose a squarylium compound having a structure in which a benzene ring is bonded to both sides of a squarylium skeleton, and Patent Documents 3 and 4 have a heterocyclic ring bonded to both sides of a squarylium skeleton via a carbon atom. A squarylium compound having the structure is disclosed. Patent Document 5 discloses a squarylium compound having a structure in which benzene rings (indoline rings) are bonded to both sides of a squarylium skeleton and these benzene rings are connected via an organic linking group. Patent Document 6 discloses a squarylium compound having a structure in which a heterocycle is bonded to both sides of a squarylium skeleton via a carbon atom, and the carbon atom and the carbon atom constituting the heterocycle form a hydrocarbon ring. Yes.

JP 2012-8532 A JP2015-86378A JP 2008-308602 A JP 2014-148567 A Japanese Patent Laying-Open No. 2015-176046 Japanese Patent Laid-Open No. 2006-74649

  A squarylium compound is expected to be used for a cut filter, a near-infrared absorbing film, a security ink, and the like for a near-infrared light by utilizing a characteristic having an absorption region in a red to near-infrared region. When the squarylium compound is applied to such a use, it is desirable that the squarylium compound has a sharp absorption peak as much as possible so that light in a desired wavelength range can be selectively absorbed. However, in the squarylium compound, a shoulder peak is likely to be recognized on the short wavelength side of the absorption peak exhibiting maximum absorption in the red to near-infrared region. In Patent Document 6, in order to reduce such a shoulder peak, a squarylium skeleton is included. A squarylium compound having a molecular design so that a heterocycle is bonded via a carbon atom, and the carbon atom and the carbon atom constituting the heterocycle form a hydrocarbon ring is disclosed. According to the squarylium compound disclosed in Patent Document 6, a relatively sharp absorption peak is exhibited in the red to near-infrared region, but a squarylium compound exhibiting a sharper absorption peak is preferable.

  This invention is made | formed in view of the said situation, The objective is to provide the squarylium compound which shows a sharp absorption peak in red-a near infrared region.

［式（１）中、
Ｒ¹とＲ⁴は互いに連結しており、
Ｒ²、Ｒ³、Ｒ⁵およびＲ⁶はそれぞれ独立して、水素原子、有機基または極性官能基を表し、
環Ａおよび環Ｂはそれぞれ独立して、置換基を有していてもよい６員以上の非芳香族炭化水素環または置換基を有していてもよい６員以上の非芳香族複素環を表す。］
［２］ 前記Ｒ¹は下記式（２）で表される基を表し、前記Ｒ⁴は下記式（３）で表される基を表す［１］に記載のスクアリリウム化合物。
−ＮＨ−Ｒ⁷ （２）
−ＮＨ−Ｒ⁸ （３）
［式（２）および式（３）において、Ｒ⁷とＲ⁸は互いに連結している。］
［３］ 下記式（５）で表される［１］または［２］に記載のスクアリリウム化合物。

［式（５）中、Ｒ²、Ｒ³、Ｒ⁵、Ｒ⁶、環Ａおよび環Ｂは上記と同じ意味を表し、Ｘ¹およびＸ²はそれぞれ独立して、カルボニル基またはスルホニル基を表し、Ｙは有機連結基を表す。］
［４］ 前記Ｘ¹およびＸ²はカルボニル基を表し、前記Ｙは、置換基を有していてもよいアルキレン基、置換基を有していてもよいアリーレン基、置換基を有していてもよいヘテロアリーレン基、またはこれらの基が単結合、−Ｏ−、−ＣＯ−、−Ｓ−または−ＮＨ−で結合した連結基を表す［３］に記載のスクアリリウム化合物。
［５］ 前記Ｒ²、Ｒ³、Ｒ⁵およびＲ⁶はそれぞれ独立して、水素原子、アルキル基、アリール基、アラルキル基、アミノ基または水酸基を表す［１］〜［４］のいずれかに記載のスクアリリウム化合物。
［６］ クロロホルム中で測定される波長４５０ｎｍ〜１１００ｎｍの範囲における吸収スペクトルが、最大吸収ピークの極大波長λmaxにおける吸光度を１としたときに、前記極大波長λmaxよりも短波長側の吸光度０．５における傾きが３．２５×１０^-2ｎｍ^-1以上であることを特徴とするスクアリリウム化合物。
［７］ ［１］〜［６］のいずれかに記載のスクアリリウム化合物と樹脂成分とを含むことを特徴とする樹脂組成物。
［８］ ［７］に記載の樹脂組成物を含むことを特徴とする光学フィルター。
［９］ ［８］に記載の光学フィルターを備えることを特徴とするセンサー。 The present invention includes the following inventions.
[1] A squarylium compound represented by the following formula (1).

[In Formula (1),
R ¹ and R ⁴ are connected to each other,
R ² , R ³ , R ⁵ and R ⁶ each independently represents a hydrogen atom, an organic group or a polar functional group,
Ring A and Ring B are each independently a 6-membered or more non-aromatic hydrocarbon ring which may have a substituent or a 6-membered or more non-aromatic heterocyclic ring which may have a substituent. Represent. ]
[2] The squarylium compound according to [1], wherein R ¹ represents a group represented by the following formula (2), and R ⁴ represents a group represented by the following formula (3).
—NH—R ⁷ (2)
—NH—R ⁸ (3)
[In Formula (2) and Formula (3), R ⁷ and R ⁸ are linked to each other. ]
[3] The squarylium compound according to [1] or [2] represented by the following formula (5).

[In Formula (5), R ² , R ³ , R ⁵ , R ⁶ , Ring A and Ring B represent the same meaning as described above, and X ¹ and X ² each independently represent a carbonyl group or a sulfonyl group. , Y represents an organic linking group. ]
[4] The X ¹ and X ² represent a carbonyl group, and the Y has an alkylene group which may have a substituent, an arylene group which may have a substituent, and a substituent. The squarylium compound according to [3], which may represent a heteroarylene group or a linking group in which these groups are bonded by a single bond, -O-, -CO-, -S-, or -NH-.
[5] R ² , R ³ , R ⁵ and R ⁶ are each independently any one of [1] to [4], each representing a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an amino group or a hydroxyl group. The squarylium compound described.
[6] When the absorption spectrum in the wavelength range of 450 nm to 1100 nm measured in chloroform has an absorbance at the maximum wavelength λmax of the maximum absorption peak as 1, the absorbance 0.5 on the shorter wavelength side than the maximum wavelength λmax is 0.5. A squarylium compound having a slope of 3.25 × 10 ⁻² nm ⁻¹ or more.
[7] A resin composition comprising the squarylium compound according to any one of [1] to [6] and a resin component.
[8] An optical filter comprising the resin composition according to [7].
[9] A sensor comprising the optical filter according to [8].

  The squarylium compound of the present invention exhibits a sharp absorption peak in the red to near infrared region. Therefore, according to the squarylium compound of the present invention, more selective light absorption is possible.

The absorption spectrum of the squarylium compound examined in the Example is represented.

  A squarylium compound having an absorption peak in the red to near-infrared region while exhibiting high light transmittance in a wide range in the visible light region is known. Therefore, application of the squarylium compound to various uses such as a near-infrared cut filter, a near-infrared absorbing film, and a security ink has been studied using such light absorption characteristics. The squarylium compound of the present invention is capable of more selectively cutting (absorbing) light in the red to near infrared region when applied to such applications. In addition to showing a sharp absorption peak in the infrared region, it is possible to show a higher light transmittance on the visible light region side (short wavelength side).

The squarylium compound of the present invention is preferably represented by the following formula (1) when viewed from a structural aspect. In the following formula (1), R ¹ and R ⁴ are connected to each other, R ² , R ³ , R ⁵ and R ⁶ each independently represent a hydrogen atom, an organic group or a polar functional group, and ring A And ring B each independently represents a 6-membered or more non-aromatic hydrocarbon ring which may have a substituent or a 6-membered or more non-aromatic heterocyclic ring which may have a substituent.

  In the squarylium compound represented by the above formula (1), when the absorption spectrum is measured, the inclination of the inclined portion on the short wavelength side of the maximum absorption peak becomes steep, and the boundary between the transmission wavelength range and the absorption wavelength range is obtained. It can be formed sharply. Therefore, it becomes possible to selectively cut light in a wavelength region corresponding to the maximum absorption peak. In addition, on the short wavelength side of the maximum absorption peak, high light transmittance is exhibited.

  In the squarylium compound, there may be a compound having a resonance relationship. Examples of the compound having a resonance relationship with the squarylium compound of the formula (1) include compounds represented by the following formulas (1a) and (1b). The squarylium compound of the present invention includes all these compounds having a resonance relationship. Specifically, the squarylium compound of the formula (1) includes a resonance relationship represented by the following formulas (1a) and (1b). Are included.

In the formula (1), groups bonded to one side and the other side of the squarylium skeleton may be the same as or different from each other. That is, R ¹ , R ² , R ³ and ring A may be the same as or different from R ⁴ , R ⁵ , R ⁶ and ring B, respectively. In the case where the groups bonded to one side and the other side of the squarylium skeleton are the same, the durability of the squarylium compound against heat and light can be expected. When the groups bonded to one side and the other side of the squarylium skeleton are different from each other, the association and aggregation of the molecules of the squarylium compound are suppressed, and an improvement in solubility in solvents and resins can be expected.

Examples of the organic group represented by R ² , R ³ , R ⁵ and R ^{6 in} the formula (1) include an alkyl group, an alkoxy group, an alkylthio group, an alkoxycarbonyl group, an alkylsulfonyl group, an alkylsulfinyl group, an aryl group, and an aralkyl group. , Aryloxy group, arylthio group, aryloxycarbonyl group, arylsulfonyl group, arylsulfinyl group, heteroaryl group, amino group, amide group, sulfonamide group, carboxy group (carboxylic acid group), cyano group and the like. Examples of the polar functional group of R ² , R ³ , R ⁵ and R ^{6 in} the formula (1) include a halogeno group, a hydroxyl group, a nitro group, and a sulfo group (sulfonic acid group).

  Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group. A linear or branched alkyl group such as a group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group; cyclopropyl group, cyclobutyl group, cyclopentyl group, Examples thereof include alicyclic alkyl groups such as cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, and cyclodecyl group. The alkyl group preferably has 1 to 20 carbon atoms. Specifically, if it is a linear or branched alkyl group, it preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 4 to 10 carbon atoms are preferred and 5 to 8 carbon atoms are more preferred if they are alicyclic alkyl groups. The alkyl group may have a substituent, and examples of the substituent of the alkyl group include an aryl group, a heteroaryl group, a halogeno group, a hydroxyl group, a carboxy group, an alkoxy group, a cyano group, a nitro group, an amino group, A sulfo group etc. are mentioned. Examples of the alkyl group having a halogeno group include a monohalogenoalkyl group, a dihalogenoalkyl group, an alkyl group having a trihalomethyl unit, and a perhalogenoalkyl group. As the halogeno group, a fluorine atom, a chlorine atom and a bromine atom are preferable, and a fluorine atom is particularly preferable.

  Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group, and a dodecyloxy group. A tridecyloxy group, a tetradecyloxy group, a pentadecyloxy group, a hexadecyloxy group, a heptadecyloxy group, an octadecyloxy group, a nonadecyloxy group, an icosyloxy group, and the like. 1-20 are preferable, as for carbon number of an alkoxy group, More preferably, it is 1-10, More preferably, it is 1-5. The alkyl group in the alkoxy group may be linear or branched.

  Examples of the alkylthio group include methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, hexylthio group, heptylthio group, octylthio group, nonylthio group, decylthio group, undecylthio group, dodecylthio group, tridecylthio group, tetradecylthio group Group, pentadecylthio group, hexadecylthio group, heptadecylthio group, octadecylthio group, nonadecylthio group, icosylthio group and the like. 1-20 are preferable, as for carbon number of an alkylthio group, More preferably, it is 1-10, More preferably, it is 1-5. The alkyl group in the alkylthio group may be linear or branched.

  Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, a butoxycarbonyl group, a pentyloxycarbonyl group, a hexyloxycarbonyl group, a heptyloxycarbonyl group, an octyloxycarbonyl group, a decyloxycarbonyl group, In addition to unsubstituted alkoxycarbonyl groups such as octadecyloxycarbonyl group, substituted alkoxycarbonyl groups such as trifluoromethyloxycarbonyl group can be mentioned. Here, examples of the substituent include a halogeno group. 2-20 are preferable, as for carbon number of an alkoxycarbonyl group, More preferably, it is 2-10, More preferably, it is 2-5. The alkyl group in the alkoxycarbonyl group may be linear or branched.

  Examples of the alkylsulfonyl group include a methylsulfonyl group, an ethylsulfonyl group, a propylsulfonyl group, an isopropylsulfonyl group, a butylsulfonyl group, a hexylsulfonyl group, a cyclohexylsulfonyl group, a 2-ethylhexylsulfonyl group, an octylsulfonyl group, and a methoxymethylsulfonyl. And a substituted or unsubstituted alkylsulfonyl group such as a group, a cyanomethylsulfonyl group, and a trifluoromethylsulfonyl group. 1-20 are preferable, as for carbon number of an alkylsulfonyl group, More preferably, it is 1-10, More preferably, it is 1-5. The alkyl group in the alkylsulfonyl group may be linear or branched.

  Examples of the alkylsulfinyl group include a methylsulfinyl group, an ethylsulfinyl group, a propylsulfinyl group, an isopropylsulfinyl group, a butylsulfinyl group, a hexylsulfinyl group, a cyclohexylsulfinyl group, a 2-ethylhexylsulfinyl group, an octylsulfinyl group, and a methoxymethylsulfinyl group. And substituted or unsubstituted alkylsulfinyl groups such as a group, a cyanomethylsulfinyl group, and a trifluoromethylsulfinyl group. 1-20 are preferable, as for carbon number of an alkylsulfinyl group, More preferably, it is 1-10, More preferably, it is 1-5. The alkyl group in the alkylsulfinyl group may be linear or branched.

  Examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, an indenyl group, an azulenyl group, a fluorenyl group, a terphenyl group, a quarterphenyl group, a pentarenyl group, a heptaenyl group, and a biphenylenyl group. Group, indacenyl group, acenaphthylenyl group, phenalenyl group and the like. 6-25 are preferable and, as for carbon number of an aryl group, More preferably, it is 6-15. The aryl group may have a substituent, and examples of the substituent of the aryl group include an alkyl group, an alkoxy group, a heteroaryl group, a halogeno group, a halogenoalkyl group, a hydroxyl group, a cyano group, a nitro group, and an amino group. , Thiocyanate group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfo group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group and the like. The aryl group may be condensed with a heteroaryl group.

  Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a phenylbutyl group, and a phenylpentyl group. The aralkyl group may have a substituent, and examples of the substituent that the aralkyl group has include an alkyl group, an alkoxy group, a halogeno group, a halogenoalkyl group, a cyano group, a nitro group, a thiocyanate group, an acyl group, and an alkoxycarbonyl group. Group, aryloxycarbonyl group, carbamoyl group, sulfo group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group and the like. 7-25 are preferable and, as for carbon number of an aralkyl group, 7-15 are more preferable.

  Examples of the aryloxy group include phenyloxy group, biphenyloxy group, naphthyloxy group, anthryloxy group, phenanthryloxy group, pyrenyloxy group, indenyloxy group, azulenyloxy group, fluorenyloxy group, Examples include a phenyloxy group, a quarterphenyloxy group, a pentarenyloxy group, a heptaenyloxy group, a biphenylenyloxy group, an indacenyloxy group, an acenaphthylenyloxy group, and a phenalenyloxy group. 6-25 are preferable and, as for carbon number of an aryloxy group, More preferably, it is 6-15.

  Examples of the arylthio group include phenylthio, biphenylthio, naphthylthio, anthrylthio, phenanthrylthio, pyrenylthio, indenylthio, azulenylthio, fluorenylthio, terphenylthio, quarterphenylthio, pentaleni Examples include a ruthio group, a heptaenylthio group, a biphenylenylthio group, an indacenylthio group, an acenaphthylenylthio group, and a phenalenylthio group. 6-25 are preferable and, as for carbon number of an arylthio group, More preferably, it is 6-15.

  Examples of the aryloxycarbonyl group include phenoxycarbonyl group, 4-dimethylaminophenyloxycarbonyl group, 4-diethylaminophenyloxycarbonyl group, 2-chlorophenyloxycarbonyl group, 2-methylphenyloxycarbonyl group, 2-methoxyphenyl. Oxycarbonyl group, 2-butoxyphenyloxycarbonyl group, 3-chlorophenyloxycarbonyl group, 3-trifluoromethylphenyloxycarbonyl group, 3-cyanophenyloxycarbonyl group, 3-nitrophenyloxycarbonyl group, 4-fluorophenyloxy A substituted or unsubstituted phenyloxycarbonyl group such as a carbonyl group, 4-cyanophenyloxycarbonyl group, 4-methoxyphenyloxycarbonyl group, etc .; 1-naphthyloxy Carbonyl group, 2-substituted or unsubstituted naphthyl oxycarbonyl group such as a naphthyloxycarbonyl group and the like. 7-25 are preferable and, as for carbon number of an aryloxycarbonyl group, More preferably, it is 7-15.

  Examples of the arylsulfonyl group include a phenylsulfonyl group, a 1-naphthylsulfonyl group, a 2-naphthylsulfonyl group, a 2-chlorophenylsulfonyl group, a 2-methylphenylsulfonyl group, a 2-methoxyphenylsulfonyl group, and 2-butoxyphenylsulfonyl. Group, 2-fluorophenylsulfonyl group, 3-methylphenylsulfonyl group, 3-chlorophenylsulfonyl group, 3-trifluoromethylphenylsulfonyl group, 3-cyanophenylsulfonyl group, 3-nitrophenylsulfonyl group, 3-fluorophenylsulfonyl Group, 4-methylphenylsulfonyl group, 4-fluorophenylsulfonyl group, 4-cyanophenylsulfonyl group, 4-methoxyphenylsulfonyl group, 4-dimethylaminophenylsulfonyl group, etc. Other unsubstituted phenylsulfonyl group; 1-naphthylsulfonyl group, 2-naphthylsulfonyl, substituted or unsubstituted naphthylsulfonyl group such as and the like. 6-25 are preferable and, as for carbon number of an arylsulfonyl group, 6-15 are more preferable.

  Examples of the arylsulfinyl group include a phenylsulfinyl group, a 2-chlorophenylsulfinyl group, a 2-methylphenylsulfinyl group, a 2-methoxyphenylsulfinyl group, a 2-butoxyphenylsulfinyl group, a 2-fluorophenylsulfinyl group, and 3-methyl. Phenylsulfinyl group, 3-chlorophenylsulfinyl group, 3-trifluoromethylphenylsulfinyl group, 3-cyanophenylsulfinyl group, 3-nitrophenylsulfinyl group, 4-methylphenylsulfinyl group, 4-fluorophenylsulfinyl group, 4-cyano Substituted or unsubstituted phenylsulfinyl group such as phenylsulfinyl group, 4-methoxyphenylsulfinyl group, 4-dimethylaminophenylsulfinyl group; 1-naphthyls Finiru group, 2-naphthylsulfinyl substituted or unsubstituted naphthylsulfinyl group such as and the like. 6-25 are preferable and, as for carbon number of an aryl sulfinyl group, 6-15 are more preferable.

  Examples of the heteroaryl group include thienyl group, thiopyranyl group, isothiochromenyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyralidinyl group, pyrimidinyl group, pyridazinyl group, thiazolyl group, isothiazolyl group, furanyl group, A pyranyl group etc. are mentioned. 2-20 are preferable and, as for carbon number of a heteroaryl group, 3-15 are more preferable. The heteroaryl group may have a substituent, and examples of the substituent that the heteroaryl group has include an alkyl group, an alkoxy group, an aryl group, a halogeno group, a halogenoalkyl group, a hydroxyl group, a cyano group, an amino group, and a nitro group. , Thiocyanate group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfo group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group and the like. The heteroaryl group may be condensed with an aryl group.

The amino group is represented by the formula: —NR ^a1 R ^a2 , and R ^a1 and R ^a2 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, or a heteroaryl group. Some are listed. Specific examples of the alkyl group, aryl group, aralkyl group, and heteroaryl group include the substituents exemplified above. Examples of the alkenyl group and alkynyl group include a part of the carbon-carbon single bond of the alkyl group exemplified above. Are substituted by a double bond or a triple bond, and in these substituents, a part of the hydrogen atoms may be substituted by a halogen atom. R ^a1 and R ^a2 may be linked to each other to form a ring.

Examples of the amide group include those represented by the formula: —NHCOR ^a3 , wherein R ^a3 is an alkyl group, an aryl group, an aralkyl group, or a heteroaryl group. Specific examples of the alkyl group, aryl group, aralkyl group, and heteroaryl group include the substituents exemplified above, and a part of hydrogen atoms may be substituted with a halogen atom.

Examples of the sulfonamide group include those represented by the formula: —NHSO ₂ R ^a4 , wherein R ^a4 is an alkyl group, an aryl group, an aralkyl group, or a heteroaryl group. Specific examples of the alkyl group, aryl group, aralkyl group, and heteroaryl group include the substituents exemplified above, and a part of hydrogen atoms may be substituted with a halogen atom.

  Examples of the halogeno group include a fluoro group, a chloro group, a bromo group, and an iodo group.

In the squarylium compound of the formula (1), R ¹ and R ⁴ are connected to each other to form a ring structure including a squarylium skeleton and benzene rings bonded to both sides thereof. By forming such a ring structure, the durability of the squarylium compound is increased. Examples of the group formed by connecting R ¹ and R ⁴ to each other include an alkylene group, an arylene group, a heteroarylene group, —O—, —CO—, —S—, —SO ₂ —, —NH—, and Examples thereof include a linking group obtained by combining these groups. The alkylene group may be linear or branched. The alkylene group preferably has 6 or more carbon atoms, more preferably 7 or more carbon atoms, preferably 16 or less, more preferably 12 or less, and still more preferably 10 or less. The number of ring members of the arylene group and the heteroarylene group is preferably 4 or more, more preferably 5 or more, and preferably 10 or less, more preferably 8 or less. An alkylene group, an arylene group, and a heteroarylene group have a part of hydrogen atom, for example, an alkyl group (except for an alkylene group), an alkoxy group, an aryl group, a heteroaryl group, a halogeno group, a hydroxyl group, a cyano group, and a nitro group. , Amino groups, thiocyanate groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, carbamoyl groups, sulfo groups, alkylsulfinyl groups, arylsulfinyl groups, alkylsulfonyl groups, arylsulfonyl groups, sulfamoyl groups, etc. The details of these substituents are often referred to the above description.

In the formula (1), R ¹ is preferably a group represented by the following formula (2), and R ⁴ is preferably a group represented by the following formula (3).
—NH—R ⁷ (2)
—NH—R ⁸ (3)

In the above formulas (2) and (3), R ^{7 in} formula (2) and R ^{8 in} formula (3) are connected to each other. In this case, an amino group (a group containing —NH—) is bonded to the R ¹ and R ⁴ positions of the benzene ring of the formula (1), whereby the hydrogen of the amino group is hydrogen bonded to the oxygen atom of the squarylium skeleton. Therefore, the squarylium compound is likely to have a stable planar structure.

Examples of the linking group formed by linking R ⁷ and R ⁸ to each other include an alkylene group, an arylene group, a heteroarylene group, —O—, —CO—, —S—, —SO ₂ —, —NH—, And a linking group obtained by combining these groups. Details of the squarylium compound in which R ⁷ and R ⁸ are linked to each other will be described below.

R ² , R ³ , R ⁵ and R ^{6 in} formula (1) are each independently preferably a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an amino group or a hydroxyl group. Details of these groups are as follows: Reference is made to the above description. Such a squarylium compound is relatively easy to produce, and by appropriately selecting the substituents R ² , R ³ , R ⁵ and R ⁶ , the maximum absorption wavelength can be controlled to a desired wavelength range, Solubility can be increased. Among these, from the viewpoint of stability and ease of production of the squarylium compound, R ² , R ³ , R ⁵ and R ⁶ are preferably each independently a hydrogen atom or an alkyl group. In this case, the alkyl group is preferably linear or branched, and the carbon number thereof is preferably 1 to 6, more preferably 1 to 4, and still more preferably 1 to 3.

  Ring A and ring B in the formula (1) are 6-membered or more non-aromatic hydrocarbon rings or 6-membered or more non-aromatic heterocycles, and these hydrocarbon rings or heterocycles have a substituent. May be. The squarylium compound of the present invention is composed of a non-aromatic hydrocarbon ring or a non-aromatic heterocyclic ring in which ring A and ring B are 6 or more members, and therefore, compared with a hydrocarbon ring or a heterocyclic ring having a smaller number of ring members. The inclination of the inclined part on the short wavelength side of the maximum absorption peak of the absorption spectrum becomes steep.

  The non-aromatic hydrocarbon ring of the ring A and the ring B in the formula (1) is not particularly limited as long as it is a hydrocarbon ring having 6 or more ring members and having no aromaticity, and examples thereof include cyclohexane and cycloheptane. Cycloalkanes; cycloalkenes such as cyclohexene, cyclohexadiene (for example, 1,3-cyclohexadiene), cycloheptene, cycloheptadiene, and the like. 6-12 are preferable, as for the number of ring members of a non-aromatic hydrocarbon ring, 6-10 are more preferable, and 6-8 are more preferable.

  The non-aromatic heterocycle of the ring A and the ring B of the formula (1) is not particularly limited as long as it is a heterocycle having 6 or more ring members and no aromaticity. Examples include a ring in which one or more carbon atoms constituting the ring are replaced with at least one atom selected from N (nitrogen atom), S (sulfur atom), and O (oxygen atom). Examples of the non-aromatic heterocycle include imidazoline ring, piperidine ring, tetrahydropyran ring, tetrahydrothiopyran ring, morpholine ring, hexamethyleneimine ring, hexamethylene oxide ring, hexamethylene sulfide ring, heptamethyleneimine ring and the like. It is done. 6-12 are preferable, as for the number of ring members of a non-aromatic heterocyclic ring, 6-10 are more preferable, and 6-8 are more preferable.

  Ring A and ring B may have a substituent, and examples of such a substituent include the organic groups and polar functional groups described above. Two or more substituents may be bonded to ring A or ring B. Among them, the substituent that the ring A and the ring B may have is preferably an alkyl group, an alkoxy group, an aryl group, a halogeno group, a halogenoalkyl group, or a hydroxyl group, and more preferably an alkyl group, an alkoxy group, or an aryl group. . In this case, the alkyl group, alkoxy group, and halogenoalkyl group preferably have 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms, still more preferably 1 to 3 carbon atoms, and the aryl group has 6 to 12 carbon atoms. Preferably, 6 to 10 is more preferable. Ring A and ring B may not have a substituent.

  Ring A and ring B are preferably heterocycles, and are heterocycles in which a nitrogen atom is bonded to the carbon atom at the para position of the bond position of the squarylium skeleton of the benzene ring to which ring A or ring B is bonded (condensed). It is more preferable. If ring A and ring B are formed of such a heterocyclic ring, the maximum absorption peak of the squarylium compound is shifted to the long wavelength side (for example, around 690 nm or more), and the light transmittance in the red region is increased. Thus, the color of the transmitted light can be brought close to the actual one. Moreover, the effect that manufacture of a squarylium compound becomes easy is also acquired. As a squarylium compound having such ring A and ring B, for example, a compound represented by the following formula (4) is shown.

In the formula (4), R ^{1 to} R ⁶ are as described above. R ¹⁰ represents a hydrogen atom or a substituent bonded to the carbon atom constituting the ring A, R ¹² represents a hydrogen atom or a substituent bonded to the carbon atom constituting the ring B, and ma and mb are 1 or more. Represents an integer. A plurality of R ¹⁰ may be the being the same or different, a plurality of R ¹² may be the same or different from each other.

R ⁹ and R ¹¹ are each independently preferably a hydrogen atom, an alkyl group, an aryl group, or a halogenoalkyl group, and more preferably a hydrogen atom or an alkyl group. 1-8 are preferable, as for carbon number of the alkyl group in this case, 1-5 are more preferable, and 1-3 are more preferable.

R ¹⁰ and R ¹² are each independently preferably a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a halogeno group, a halogenoalkyl group, or a group or atom selected from the group consisting of a hydroxyl group, More preferably, it is a group or atom selected from the group consisting of an alkyl group, an alkoxy group, and an aryl group, and more preferably a group or atom selected from the group consisting of a hydrogen atom, an alkyl group, and an alkoxy group. . 1-8 are preferable, as for carbon number of the alkyl group and alkoxy group in this case, 1-5 are more preferable, and 1-3 are more preferable.

  ma and mb are preferably integers of 1 to 7, more preferably 1 to 5, and even more preferably 1 to 3.

The squarylium compound of the present invention has a structure in which R ¹ and R ⁴ are linked to each other in the above formula (1), and among them, a compound represented by the following formula (5) is preferably shown. Such a squarylium compound is easy to manufacture and has excellent stability.

In the above formula (5), R ² , R ³ , R ⁵ , R ⁶ , ring A and ring B are as described above. X ¹ and X ² each independently represent a carbonyl group or a sulfonyl group. Y represents an organic linking group, preferably an alkylene group which may have a substituent, an arylene group which may have a substituent, a heteroarylene group which may have a substituent, or these Represents a linking group in which these groups are bonded by a single bond, -O-, -CO-, -S- or -NH-. The alkylene group may be linear or branched. The alkylene group preferably has 6 or more carbon atoms, more preferably 7 or more carbon atoms, preferably 16 or less, more preferably 14 or less, and still more preferably 12 or less. The number of ring members of the arylene group and the heteroarylene group is preferably 4 or more, more preferably 5 or more, and preferably 10 or less, more preferably 8 or less. Thus, the durability of the squarylium compound is significantly improved by connecting the benzene rings on both sides of the squarylium skeleton via the linking group.

  Examples of the substituent that the linking group Y may have include an alkyl group (excluding an alkylene group), an alkoxy group, an aryl group, a heteroaryl group, a halogeno group, a hydroxyl group, a cyano group, a nitro group, an amino group, Examples include thiocyanate group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfo group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, among others, alkyl group, aryl It is preferably at least one selected from the group consisting of a group, a halogeno group, and a hydroxyl group.

  From the viewpoint of ease of production of the squarylium compound, the linking group Y is preferably an alkylene group which may have a substituent. In addition, the linking group Y in which a plurality of arylene groups which may have a substituent are bonded with a single bond, —O—, —CO—, —S— or —NH— is also preferable. With such a linking group Y, for example, when the di (sulfone) amide compound represented by the formula (7-3) described below is reacted with squaric acid, the squaric acid is bonded to both ends of the di (sulfone) amide compound. A squarylium compound represented by the formula (5) can be easily produced by bonding with a benzene ring to form a ring structure.

X ¹ and X ^{2 in} the formula (5) are preferably carbonyl groups from the viewpoint of ease of production of the squarylium compound.

In the squarylium compound represented by the formula (5), the ring A and the ring B are preferably nitrogen-containing heterocycles, and a compound represented by the following formula (6) is preferably shown. In the following formula (6), the above description is referred to for R ² , R ³ , R ⁵ , R ⁶ , R ^{9 to} R ¹² , X ¹ , X ² , Y, ma and mb.

Preferable examples of the squarylium compound represented by the formula (6) include compounds represented by the following formula (6-1) and the formula (6-2). In the following formulas (6-1) and (6-2), R ² , R ³ , R ⁵ , R ⁶ , R ^{9 to} R ¹² , ma and mb are referred to the above description, and n is 6 to 16 Represents an integer.

The squarylium compound of the present invention preferably has the following characteristics from the aspect of the absorption spectrum. That is, the squarylium compound of the present invention has an absorption spectrum in the wavelength range of 450 nm to 1100 nm measured in chloroform, where the absorbance at the maximum wavelength λmax of the maximum absorption peak is 1, and the shorter wavelength side than the maximum wavelength λmax. It is preferable that the slope at an absorbance of 0.5 is 0.325 × 10 ⁻² nm ⁻¹ or more. Such a squarylium compound forms a sharp boundary between the transmission wavelength region and the absorption wavelength region because the inclination of the inclined portion on the short wavelength side of the maximum absorption peak becomes steep when the absorption spectrum is measured. be able to. Therefore, it is possible to selectively cut light in the wavelength range corresponding to the maximum absorption peak. For example, while selectively cutting light in the near infrared region, light in the visible light region on the shorter wavelength side than that. Can be transmitted at a high transmittance including red light, and the color of the transmitted light can be brought close to the actual one.

  The absorption spectrum is obtained by measuring the absorbance at a measurement pitch of 1 nm in the wavelength range of 450 nm to 1100 nm. The absorbance value at a wavelength below the measurement pitch (1 nm) is calculated by linear interpolation from the absorbance measurement value at the 1 nm pitch. The concentration of the squarylium compound in chloroform is adjusted so that the maximum absorbance (maximum absorbance at the maximum absorption peak) is 1 ± 0.003 in the wavelength range of 450 nm to 1100 nm. In the present invention, when the absorption spectrum is measured under such conditions, the absorbance at the absorption wavelength λmax of the maximum absorption peak is regarded as 1. The following various absorption spectrum characteristics are also defined based on the absorption spectrum measured under the same conditions.

The slope S _{0.5 at} the absorbance 0.5 on the shorter wavelength side than the maximum wavelength λmax is λ _{0.55 for} the wavelength where the absorbance is 0.55 on the shorter wavelength side than λmax, and the wavelength for the absorbance 0.45 is λ _0.45 . Then, it is obtained by the formula: S _0.5 = (0.55-0.45) / (λ _0.55 -λ _0.45 ). Wavelength lambda _0.55 absorbance becomes 0.55, the wavelength lambda _0.45 absorbance becomes 0.45, determined by linear interpolation from the measured absorbance of 1nm pitch. Note that λ _0.55 means the wavelength closest to λmax where the absorbance is 0.55 on the shorter wavelength side than λmax, and λ _0.45 is the closest to λmax where the absorbance is 0.45 on the shorter wavelength side than λmax. It means near wavelength.

The slope S _0.5 at an absorbance of _0.5 is 3.25 × 10 ⁻² nm ⁻¹ or more, preferably 3.30 × 10 ⁻² nm ⁻¹ or more, more preferably 3.35 × 10 ⁻² nm ^{−. 1} or more. The upper limit of the slope S _0.5 is not particularly limited, but may be, for example, 5.00 × 10 ⁻² nm ⁻¹ or less, or 4.00 × 10 ⁻² nm ⁻¹ or less, or 3.75 × It may be 10 ⁻² nm ⁻¹ or less.

  The maximum absorption peak is preferably such that a shoulder peak is not observed as much as possible on the shorter wavelength side than the absorption maximum λmax. Specifically, it is preferable that the absorption spectrum does not have an absorption maximum in which the absorbance increases by 0.05 or more in the range from the maximum wavelength λmax of the maximum absorption peak to 100 nm on the short wavelength side. That is, in the absorption spectrum measured at a pitch of 1 nm, there is no absorption maximum in the wavelength range from λmax-100 (nm) to λmax (nm), or even when there is an absorption maximum, the longer wavelength side and the shorter wavelength side. It is preferable that the increase in absorbance is less than 0.05. Thereby, the boundary between the transmission wavelength region and the absorption wavelength region can be sharply formed. The increase in absorbance at the shoulder peak is more preferably less than 0.03, more preferably less than 0.01, and particularly preferably no absorption maximum of the shoulder peak.

From the same point of view, the maximum absorption peak has an inclination S _{0.2 at} an absorbance 0.2 on the shorter wavelength side than the maximum wavelength λmax of 1.00 × 10 ⁻² nm ⁻¹ or more and an absorbance of 0.2-0. Preferably, the slope monotonically decreases between 5. The slope S _0.2 is more preferably 1.10 × 10 ⁻² nm ⁻¹ or more, and further preferably 1.15 × 10 ⁻² nm ⁻¹ or more. The slope S _0.2 is expressed by the equation: S _0.2 = (0.22−) where λ _0.22 is the wavelength at which the absorbance is 0.22 on the shorter wavelength side than λmax, and λ _0.18 is the wavelength at which the absorbance is 0.18. 0.18) / (λ _0.22 −λ _0.18 ). Wavelength lambda _0.22 absorbance becomes 0.22, the wavelength lambda _0.18 absorbance becomes 0.18 is obtained by linear interpolation from the measured absorbance of 1nm pitch. Note that λ _0.22 means the wavelength closest to λ max where the absorbance is 0.22 on the shorter wavelength side than λ max, and λ _0.18 is the closest to λ max where the absorbance is 0.18 on the shorter wavelength side than λ max. It means near wavelength.

  The maximum wavelength λmax of the maximum absorption peak is preferably 650 nm or more, more preferably 660 nm or more, further preferably 670 nm or more, more preferably 950 nm or less, more preferably 900 nm or less, further preferably 850 nm or less, and more preferably 800 nm or less. Even more preferred.

  The squarylium compound of the present invention preferably has an average absorbance in the wavelength range of 450 nm to 600 nm of 0.03 or less, more preferably 0.02 or less, and even more preferably 0.01 or less, whereby light in the visible light region. The transmittance can be increased. The average absorbance in the wavelength range of 450 nm to 600 nm is determined by averaging the absorbance values at 151 points measured at a 1 nm pitch in the wavelength range of 450 nm to 600 nm.

The squarylium compound of the present invention can be produced by reacting a compound in which R ¹ of the compound of the following formula (7-1) and R ⁴ of the compound of the following formula (7-2) are linked with squaric acid. . In the following formulas (7-1) and (7-2), R ^{1 to} R ⁶ , ring A and ring B have the same meanings as in the above formula (1), and preferred embodiments thereof have also been described above. Street. The compound of formula (7-1) and the compound of formula (7-2) may be the same.

From the viewpoint of increasing the reactivity with squaric acid, the compound in which R ¹ of the compound of formula (7-1) and R ⁴ of the compound of formula (7-2) are linked is represented by the following formula (7-3). The di (sulfone) amide compound represented is preferable. In the following formula (7-3), R ² , R ³ , R ⁵ , R ⁶ , X ¹ , X ² , Y, ring A and ring B have the same meaning as in the above formula (5), The preferred embodiment is also as described above.

  The reaction between squaric acid and the above compound is preferably carried out in the presence of a solvent. Solvents that can be used include, for example, chlorinated hydrocarbons such as chloroform and methylene chloride; aromatic hydrocarbons such as benzene, toluene, xylene and trimethylbenzene; chlorinated aromatics such as chlorotoluene and dichlorobenzene; tetrahydrofuran (THF), dioxane, cyclopentyl methyl ether, diisopropyl ether, diethyl ether and other ethers; methanol, ethanol, propanol, butanol and other alcohols; and the like. These solvents may use only 1 type and may use 2 or more types together.

  In the reaction with squaric acid, the reaction temperature may be appropriately set. For example, 30 ° C or higher is preferable, 60 ° C or higher is more preferable, 80 ° C or higher is more preferable, 170 ° C or lower is preferable, and 140 ° C or lower is more preferable. . The reaction is preferably performed under reflux. The reaction time is not particularly limited and may be appropriately set according to the progress of the reaction. For example, 0.5 hour or more is preferable, 1 hour or more is more preferable, 48 hours or less is preferable, and 24 hours or less is preferable. More preferred. The atmosphere during the reaction is preferably an inert gas (nitrogen, argon, etc.) atmosphere.

  The production of squarylium compounds can also be referred to the following article: Serguei Miltsov et al., “New Cyanine Dyes: Norindosquarocyanines”, Tetrahedron Letters, Vol. 40, Issue 21, p. 4067-4068 (1999).

  The obtained squarylium compound can be appropriately purified by known purification means such as filtration, silica gel column chromatography, alumina column chromatography, sublimation, recrystallization, and crystallization as necessary. The chemical structure of the squarylium compound can be analyzed by known analysis methods such as mass spectrometry, single crystal X-ray structure analysis, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

  The squarylium compound of the present invention can be mixed with a resin component to form a resin composition. The resin composition of the present invention can be suitably applied to an optical filter, for example, by forming a resin molded body such as a film. Resin moldings also include near-infrared absorbing films and near-infrared absorbing plates that block heat rays for energy saving, solar cell materials that use visible light and near-infrared light, plasma display panels (PDP), and specific wavelengths for CCDs. Application to an absorption filter or the like is also possible.

  The resin composition contains at least the squarylium compound of the present invention and a resin component. The squarylium compound contained in the resin composition may be only one type or two or more types.

  Although the squarylium compound of the present invention can be regarded as a kind of dye, the resin composition of the present invention contains other dye together with the squarylium compound of the present invention as long as the desired performance according to the application is ensured. May be. Examples of the dye that may be contained in the resin composition include a squarylium dye other than the squarylium compound of the present invention, a croconium dye, and copper (for example, Cu (II)) or zinc (for example, Zn) as the central metal ion. (II)) cyclic tetrapyrrole dyes (porphyrins, chlorins, phthalocyanines, cholines, etc.), cyanine dyes, quaterylene dyes, naphthalocyanine dyes, nickel complex dyes, Examples thereof include copper ion dyes, diimmonium dyes, subphthalocyanine dyes, xanthene dyes, azo dyes, and dipyrromethene dyes. These other pigments may be used alone or in combination of two or more. Among them, it is preferable to use the squarylium compound of the present invention in combination with the squarylium compound disclosed in JP-A-2006-74649 (the squarylium compound represented by the following formula (8)), and thereby, in the near infrared region. It becomes easy to form a resin composition having a wide absorption wavelength region and having a high transmittance in a wide range of the visible light region on the shorter wavelength side.

In the above formula (8), R ²¹ and R ²² each independently represent a group represented by the following formula (9). In the following formula (9), the ring P is a 4-9 membered unsaturated carbonization. Represents a hydrogen ring, ring Q represents an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, or a condensed ring containing these ring structures; R ²³ represents a hydrogen atom, an organic group or a polar functional group, R ²⁴ represents an organic group or a polar functional group, and * represents a bonding site with a 4-membered ring (squarylium skeleton) in formula (8). , K is an integer of 0 to 6 and is less than or equal to h (where h is a value obtained by subtracting 3 from the number of members of ring P), and when k is 2 or more, a plurality of R ²⁴ are the same Or different.

For details of the organic group and polar functional group of R ²³ and R ²⁴ , refer to the description of the organic group and polar functional group of R ² , R ³ , R ⁵ and R ⁶ . R ²³ is preferably a hydrogen atom, an alkyl group, an alkoxycarbonyl group or an aryl group, more preferably an alkyl group or an aryl group. In this case, the number of carbon atoms of the alkyl group is preferably 1 to 6 if it is a linear or branched alkyl group, more preferably 1 to 4, and 4 to 7 if it is an alicyclic alkyl group. Preferably, it is 5-6. 6-10 are preferable and, as for carbon number of an aryl group, More preferably, it is 6-8. When R ²³ is an alkyl group or an aryl group, a methyl group, an ethyl group, an isopropyl group, an isobutyl group, a t-butyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group and the like are preferable. R ²⁴ is preferably an alkyl group, an alkoxy group, a halogeno group, an aryl group, an alkoxycarbonyl group (ester group), an amide group, a sulfonamide group, or a hydroxyl group, more preferably an alkyl group or a hydroxyl group. Preferable examples include linear or branched alkyl groups having 1 to 4 carbon atoms. Ring P preferably has no substituent R ²⁴ , that is, k is preferably 0.

  As the structure of the ring P, for example, cyclobutene, cyclopentene, cyclopentadiene, cyclohexene, cyclohexadiene, cycloheptene, cycloheptadiene, cycloheptatriene, cyclooctene, cyclooctadiene, cyclooctatriene, cyclononene, cyclononadiene, cyclononatriene, Examples include cycloalkene structures such as cyclononatetraene. Of these, cycloalkane monoenes such as cyclopentene, cyclohexene, cycloheptene, and cyclooctene are preferable, and cyclohexene, cycloheptene, and cyclooctene are more preferable.

  Examples of the aromatic hydrocarbon ring of ring Q include a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, a fluoranthene ring, a cyclotetradecaheptaene ring, and the like. The aromatic hydrocarbon ring may have only one ring structure or may be a condensation of two or more ring structures. The aromatic heterocyclic ring of ring Q includes one or more atoms selected from N (nitrogen atom), O (oxygen atom) and S (sulfur atom) in the ring structure, and has aromaticity. , Furan ring, thiophene ring, pyrrole ring, pyrazole ring, oxazole ring, thiazole ring, imidazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, purine ring, pteridine ring and the like. The aromatic heterocycle may have only one ring structure, or may be a condensation of two or more ring structures. The condensed ring containing these ring structures of the ring Q has a structure in which an aromatic hydrocarbon ring and an aromatic heterocyclic ring are condensed. For example, an indole ring, an isoindole ring, a benzimidazole ring, a quinoline ring Benzopyran ring, acridine ring, xanthene ring, carbazole ring and the like.

  Ring Q may have a substituent, and examples of the substituent include the organic groups and polar functional groups described above. Among them, an alkyl group (preferably a linear or branched alkyl group having 1 to 4 carbon atoms), an aryl group, an alkoxy group (preferably an alkoxy group having 1 to 4 carbon atoms), an alkylthio group (preferably having a carbon number of 1 to 4). 2 alkylthio groups), heteroaryl groups, amino groups, amide groups, sulfonamido groups, hydroxyl groups, thiol groups, benzothiazole groups, indolinyl groups and the like; halogeno groups (preferably fluoro groups, chloro groups, Bromo group), halogenoalkyl group (preferably a perhalogenoalkyl group having 1 to 3 carbon atoms), cyano group, alkoxycarbonyl group (ester group), carboxy group (carboxylic acid group), carboxylic acid ester group, carboxylic acid amide group Preferred examples include electron-withdrawing groups such as a sulfo group (sulfonic acid group) and a nitro group. Among these, an electron withdrawing group is more preferable, and a halogeno group is particularly preferable. Ring Q may not have a substituent. When the ring Q has a substituent, the number is preferably 1 to 3, more preferably 1 to 2, and still more preferably 1.

  Specific examples of the squarylium compound represented by the formula (8) include squarylium compound 01 to squarylium compound 30 described in Examples of JP-A-2006-74649. Among these, squarylium compound 01, 07 to 11, 13, 15, 17-22, 28, 29 are preferable, squarylium compounds 17-21 are more preferable, and squarylium compounds 17, 18 are particularly preferable. That is, the ring P is preferably a cyclohexene ring or a cyclooctene ring, more preferably a cyclooctene ring, and the ring Q may have a benzene ring or a substituent which may have a substituent. A naphthalene ring is preferred. For details of the squarylium compound represented by the formula (8), refer to the description of JP-A-2006-74649.

  When the squarylium compound of the present invention is used in combination with the squarylium compound of the above formula (8), the content of the squarylium compound of the present invention is 100 mass in total of the squarylium compound of the present invention and the squarylium compound of the above formula (8). % Is preferably 20% by mass or more, more preferably 30% by mass or more, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

  When the resin composition also contains a dye other than the squarylium compound of the present invention and the squarylium compound of the above formula (8), the content of the other dye is 100 parts by weight with respect to 100 parts by weight of the squarylium compound of the present invention. The amount is preferably not more than part by weight, more preferably not more than 60 parts by weight, still more preferably not more than 30 parts by weight, and particularly preferably does not substantially contain other pigments.

  The content of the squarylium compound of the present invention in the resin composition is preferably 0.01% by mass or more in 100% by mass of the solid content of the resin composition from the viewpoint of expressing desired performance. More preferably, it is more preferably 1% by mass or more. Moreover, from the point which improves the moldability, film formability, etc. of the resin composition, the content of the squarylium compound of the present invention in the resin composition is preferably 25% by mass or less in 100% by mass of the solid content of the resin composition. 20 mass% or less is more preferable, and 15 mass% or less is further more preferable. When the resin composition also contains a dye other than the squarylium compound of the present invention, the total content thereof is preferably in the above range.

  A known resin can be used as the resin component contained in the resin composition. As the resin component, those having high transparency and capable of dissolving or dispersing the squarylium compound of the present invention are preferable. When other dyes are used in combination, the resin component is preferably one that can also dissolve or disperse other dyes. By selecting such a resin component, it is possible to achieve both high transmittance in the wavelength range desired to be transmitted and high absorbency in the wavelength range desired to be blocked.

  The resin component is not only a resin that has been completely polymerized, but also a resin raw material (including a precursor of the resin, a raw material of the precursor, a monomer constituting the resin, and the like), and when the resin composition is molded In addition, those which are incorporated into the resin by polymerization reaction or crosslinking reaction can also be used. In the present invention, any resin is included in the resin component. In the latter case, a part of the structure of the squarylium compound is caused by unreacted substances, reactive terminal functional groups, ionic groups, catalysts, acid / basic groups, etc. present in the reaction solution obtained by the polymerization reaction. Or the whole thing may break down. Therefore, when there is such a concern, it is desirable to form a resin composition by blending a squarylium compound into a resin that has been completely polymerized.

  Examples of the resin component include (meth) acrylic resins, (meth) acrylic urethane resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyolefin resins (for example, polyethylene resins and polypropylene resins), cycloolefin resins, Melamine resin, urethane resin, styrene resin, polyvinyl acetate, polyamide resin (for example, nylon), aramid resin, polyimide resin, polyamideimide resin, alkyd resin, phenol resin, epoxy resin, polyester resin (for example, polybutylene terephthalate ( PBT) resin, polyethylene terephthalate (PET) resin, polyarylate resin, etc.), polysulfone resin, butyral resin, polycarbonate resin, polyether resin, ABS resin (acrylonitrile butadiene styrene) Resin), AS resin (acrylonitrile-styrene copolymer), silicone resin, modified silicone resin (for example, (meth) acrylic silicone resin, alkylpolysiloxane resin, silicone urethane resin, silicone polyester resin, silicone acrylic resin, etc.) , Fluorinated resins (for example, fluorinated aromatic polymer, polytetrafluoroethylene (PTFE), perfluoroalkoxy fluororesin (PFA), fluorinated polyaryletherketone (FPEK), fluorinated polyimide (FPI), fluorinated polyamide Acid (FPAA), fluorinated polyether nitrile (FPEN) and the like. Among these, from the viewpoint of excellent transparency and heat resistance, polyimide resin, polyamideimide resin, (meth) acrylic resin, cycloolefin resin, epoxy resin, polyester resin, polyarylate resin, polyamide resin, polycarbonate resin, polysulfone Resins and fluorinated aromatic polymers are preferred.

  A polyimide resin is a polymer containing an imide bond in the repeating unit of the main chain. For example, polycarboxylic acid dianhydride and diamine are subjected to polycondensation to obtain polyamic acid, which is dehydrated and cyclized (imidized). ). As the polyimide resin, it is preferable to use an aromatic polyimide in which aromatic rings are connected by an imide bond. Polyimide resins include, for example, Kapton (registered trademark) manufactured by DuPont, Aurum (registered trademark) manufactured by Mitsui Chemicals, Meldin (registered trademark) manufactured by Saint-Gobain, and TPS (registered trademark) TI3000 series manufactured by Toray Plastic Seiko Co., Ltd. Etc. can be used.

  Polyamideimide resin is a polymer containing an amide bond and an imide bond in the repeating unit of the main chain. As the polyamideimide resin, for example, Torlon (registered trademark) manufactured by Solvay Advanced Polymers, Viromax (registered trademark) manufactured by Toyobo, TPS (registered trademark) TI5000 series manufactured by Toray Plastic Seiko Co., Ltd., and the like can be used.

  The (meth) acrylic resin is a polymer having a repeating unit derived from (meth) acrylic acid or a derivative thereof, for example, a repeating unit derived from a (meth) acrylic acid ester such as a poly (meth) acrylic acid ester resin. The resin which has is used preferably. The (meth) acrylic resin preferably has a ring structure in the main chain, for example, a carbonyl group-containing ring structure such as a lactone ring structure, a glutaric anhydride structure, a glutarimide structure, a maleic anhydride structure, or a maleimide ring structure; oxetane Examples include carbonyl group-free ring structures such as a ring structure, an azetidine ring structure, a tetrahydrofuran ring structure, a pyrrolidine ring structure, a tetrahydropyran ring structure, and a piperidine ring structure. The carbonyl group-containing ring structure includes a structure containing a carbonyl group derivative group such as an imide group. Examples of (meth) acrylic resins having a carbonyl group-containing ring structure include those described in JP-A No. 2004-168882, JP-A No. 2008-179777, International Publication No. 2005/54311, JP-A No. 2007-31537, and the like. Those described can be used.

  The cycloolefin resin is a polymer obtained by polymerizing a cycloolefin as at least a part of the monomer component, and is not particularly limited as long as it has an alicyclic structure in a part of the main chain. Examples of the cycloolefin-based resin include Topas (registered trademark) manufactured by Polyplastics, Appel (registered trademark) manufactured by Mitsui Chemicals, ZEONEX (registered trademark) and ZEONOR (registered trademark) manufactured by Nippon Zeon, and JSR Arton (registered trademark) or the like made by the manufacturer can be used.

  The epoxy resin is a resin that can be cured by crosslinking an epoxy compound (prepolymer) in the presence of a curing agent or a curing catalyst. Examples of the epoxy compound include aromatic epoxy compounds, aliphatic epoxy compounds, alicyclic epoxy compounds, hydrogenated epoxy compounds, and the like, for example, fluorene epoxy (Ogsol (registered trademark) PG-100) manufactured by Osaka Gas Chemical Company. Bisphenol A type epoxy compound (JER (registered trademark) 828EL) manufactured by Mitsubishi Chemical Corporation, hydrogenated bisphenol A type epoxy compound (JER (registered trademark) YX8000), alicyclic liquid epoxy compound (celloxide (registered trademark) manufactured by Daicel Corporation) Trademark) 2021P) and the like can be used.

  The polyester resin is a polymer containing an ester bond in the repeating unit of the main chain, and can be obtained, for example, by polycondensing a polyvalent carboxylic acid (dicarboxylic acid) and a polyalcohol (diol). Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like. For example, TRN series manufactured by Teijin Ltd., Teonex (registered trademark), Rynite manufactured by DuPont. (Registered trademark), Novapex (registered trademark) manufactured by Mitsubishi Chemical Corporation, Nova Duran (registered trademark) manufactured by Mitsubishi Engineering Plastics, Lumirror (registered trademark) manufactured by Toray Industries, Inc., and Toraycon (registered trademark) can be used. .

  A polyarylate resin is a polymer obtained by polycondensation of a dihydric phenol compound and a dibasic acid (for example, an aromatic dicarboxylic acid such as phthalic acid). An aromatic ring and an ester bond are added to the repeating unit of the main chain. And a repeating unit containing As the polyarylate resin, for example, Vectran (registered trademark) manufactured by Kuraray Co., Ltd., U polymer (registered trademark) manufactured by Unitika, Unifiner (registered trademark) or the like can be used.

  The polyamide resin is a polymer containing an amide bond in the repeating unit of the main chain, and can be obtained, for example, by condensation polymerization of diamine and dicarboxylic acid. The polyamide resin may have an aliphatic skeleton in the main chain, and as such an amide resin, for example, nylon can be used. The polyamide resin may have an aromatic skeleton, and an aramid resin is known as such a polyamide resin. The aramid resin is preferably used because it has excellent heat resistance and high mechanical strength. For example, Twaron (registered trademark), Conex (registered trademark) manufactured by Teijin Limited, Kevlar (registered trademark) manufactured by DuPont, Nomex (Registered trademark) or the like can be used.

  The polycarbonate resin is a polymer containing a carbonate group (—O— (C═O) —O—) in the repeating unit of the main chain. Polycarbonate resins include Panlite (registered trademark) manufactured by Teijin Limited, Iupilon (registered trademark) manufactured by Mitsubishi Engineering Plastics, Novalex (registered trademark), Zanta (registered trademark), SD Polycarbonate manufactured by Sumika Stylon Polycarbonate. (Registered trademark) or the like can be used.

The polysulfone resin is a polymer having a repeating unit containing an aromatic ring, a sulfonyl group (—SO ₂ —), and an oxygen atom. As the polysulfone resin, for example, SUMIKAEXCEL (registered trademark) PES3600P and PES4100P manufactured by Sumitomo Chemical Co., Ltd., UDEL (registered trademark) P-1700 manufactured by Solvay Specialty Polymers, Inc., and the like can be used.

  The fluorinated aromatic polymer includes an aromatic ring having one or more fluorine atoms and at least one bond selected from the group consisting of an ether bond, a ketone bond, a sulfone bond, an amide bond, an imide bond, and an ester bond. A polymer having a unit, and among these, a polymer essentially including a repeating unit containing an aromatic ring having one or more fluorine atoms and an ether bond is preferable. As the fluorinated aromatic polymer, for example, those described in JP 2008-181121 A can be used.

  The resin component preferably has high transparency, which makes it easy to suitably apply the resin composition to optical applications. For example, the resin component preferably has a total light transmittance of 75% or more at a thickness of 0.1 mm, more preferably 80% or more, and still more preferably 85% or more. The upper limit of the total light transmittance of the resin component is not particularly limited, and the total light transmittance may be 100% or less, for example, 95% or less. The total light transmittance is measured based on JIS K 7105.

  The resin component preferably has a high glass transition temperature (Tg), whereby the heat resistance of the resin composition and various molded articles obtained therefrom can be increased. For example, the glass transition temperature of the resin component is preferably 110 ° C. or higher, more preferably 120 ° C. or higher, and further preferably 130 ° C. or higher. Although the upper limit of the glass transition temperature of a resin component is not specifically limited, For example, 380 degrees C or less is preferable from the point which ensures the moldability of a resin composition.

  The resin composition may be a thermoplastic resin composition that can be used for molding such as injection molding and extrusion molding, such as spin coating, solvent casting, roll coating, spray coating, bar coating, dip coating. It may be a resin composition that is made into a paint so that it can be applied by a coating method, a screen printing method, a flexographic printing method, an ink jet method or the like.

  When the resin composition is a thermoplastic resin composition, a molded product can be obtained by subjecting the resin composition to injection molding, extrusion molding, vacuum molding, compression molding, blow molding, or the like. In this method, a thermoplastic resin is used as a resin component, a squarylium compound is added to the thermoplastic resin, and a molded product is obtained by heat molding. For example, the squarylium compound may be added to the base resin powder or pellets, heated to about 150 ° C. to 350 ° C., dissolved, and then molded. The shape of the molded product is not particularly limited, but plate shape, sheet shape, granular shape, powder shape, lump shape, particle aggregate shape, spherical shape, elliptical spherical shape, cubic shape, column shape, rod shape, cone shape, cylindrical shape, Examples include a needle shape, a fiber shape, a hollow fiber shape, and a porous shape. Moreover, when kneading | mixing resin, you may add the additive used for normal resin shaping | molding, such as a ultraviolet absorber and a plasticizer.

  When the resin composition is a coated resin composition, a liquid or paste-like resin composition containing a squarylium compound is applied on a substrate (for example, a resin plate, a film, a glass plate, etc.). Further, a sheet-like molded body such as a film having a thickness of 200 μm or less or a plate-like material having a thickness exceeding 200 μm can be formed.

  The resin composition may contain a solvent. For example, when the resin composition is a resin composition formed into a paint, application of the resin composition is facilitated by including the solvent. The resin composition formed into a paint can be obtained, for example, by dissolving the squarylium compound in a solvent containing a resin component or dispersing the squarylium compound in a solvent (dispersion medium) containing a resin component. The solvent may function as a solvent (solvent) for the squarylium compound or may function as a dispersion medium. Examples of the solvent include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; glycol derivatives such as PGMEA (2-acetoxy-1-methoxypropane), ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, and ethylene glycol ethyl ether acetate (Ether compounds, ester compounds, ether ester compounds, etc.); amides such as N, N-dimethylacetamide; esters such as ethyl acetate, propyl acetate, butyl acetate; N-methyl-pyrrolidone (specifically 1 -Pyrrolidones such as methyl-2-pyrrolidone); aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as cyclohexane and heptane; tetrahydrofuran, dioxane, diethyl ether, di Ethers such as Chirueteru; and the like. These solvents may use only 1 type and may use 2 or more types together.

  The content of the solvent is preferably 50% by mass or more, for example, preferably 70% by mass or more, more preferably less than 100% by mass, and more preferably 95% by mass or less, in 100% by mass of the resin composition. By adjusting the content of the solvent within such a range, it becomes easy to obtain a resin composition having a high squarylium compound concentration.

  It should be noted that amides such as N, N-dimethylacetamide and the like may decompose the squarylium compound, so that the amount used is preferably small. Therefore, the content of amides is preferably 60% by mass or less, more preferably 40% by mass or less, further preferably 20% by mass or less, still more preferably 5% by mass or less, and further preferably 0% by mass in 100% by mass of the resin composition. % Is particularly preferred (ie does not include amides).

  The resin composition may contain, for example, a compound (ultraviolet absorber) having an absorption ability in a wavelength range of 350 nm to 400 nm. Due to the presence of these compounds, it is possible to suppress deterioration of the resin composition due to light in the wavelength range of 350 nm to 400 nm. When a compound having an absorption ability in the wavelength range of 350 nm to 400 nm is used in combination, examples of the compound having an absorption ability in the wavelength range of 350 nm to 400 nm include TINUVIN (registered trademark) series manufactured by BASF, Sankyo Chemical Co., Ltd. Zithriser (registered trademark) series, Adeka's Adekastab (registered trademark) series, Sumitomo Chemical's Sumisorb (registered trademark) series, Kyodo Yakuhin Biosorb (registered trademark) series, Sipro Kasei's Seasorb (registered) Trademark) series or the like can be used.

  The resin composition may contain a surface conditioner, thereby suppressing appearance defects such as striations and dents in the resin layer when the resin composition is cured to form a resin layer. can do. The kind of surface conditioning agent is not specifically limited, A siloxane type surfactant, an acetylene glycol type surfactant, a fluorine type surfactant, an acrylic leveling agent, etc. can be used. As the surface conditioner, for example, BYK (registered trademark) series manufactured by Big Chemie, KF series manufactured by Shin-Etsu Chemical Co., Ltd., or the like can be used.

  The resin composition may contain a dispersant, whereby the dispersibility of the oxocarbon compound in the resin composition can be stabilized and reaggregation can be suppressed. The type of the dispersant is not particularly limited. The EFKA series manufactured by Fuka Additives, the BYK (registered trademark) series manufactured by Big Chemie, the Solsperse (registered trademark) series manufactured by Lubrizol Japan, and the Disparon manufactured by Enomoto Kasei Co., Ltd. (Registered trademark) series, Ajinomoto Fine Techno Co., Ltd. Ajisper (registered trademark) series, Shin-Etsu Chemical Co., Ltd. KP series, Kyoeisha Chemical Co., Ltd. polyflow series, DIC Co., Ltd. Megafak (registered trademark) series, Sannopco's Dispar Aid series and the like can be used.

  The resin composition may contain various additives such as a plasticizer, a surfactant, a viscosity modifier, an antifoaming agent, a preservative, a specific resistance modifier, and an adhesion improver, as necessary. .

  The resin composition of the present invention can be preferably used as a resin composition for forming a filter used in various applications such as an optical device application, a display device application, a machine part, and an electric / electronic part. The resin composition of the present invention can be suitably applied to an optical filter such as a near infrared cut filter. Such a filter may be formed from a single or a plurality of resin layers, or may be formed integrally with a support.

  The filter integrated with the support, for example, the resin composition, the surface of the support (or the surface of the other layer in the case of having another layer such as a binder layer between the support and the resin layer). ) By spin coating or solvent casting, and dried or cured. Moreover, you may form a filter by thermocompression-bonding the planar molded body formed from the resin composition with respect to the support body.

  The resin layer formed from the resin composition may be provided only on one side of the support, or may be provided on both sides. The thickness of the resin layer is not particularly limited, but is preferably, for example, 0.5 μm or more, more preferably 1 μm or more, further preferably 2 μm or more, and preferably 1 mm or less, and 500 μm from the viewpoint of securing desired near infrared ray cutting performance. The following is more preferable, and 200 μm or less is more preferable. When the resin layer is formed by applying a resin composition that has been made into a coating on the support, the strength of the filter can be secured by the support, so the thickness of the resin layer should be further reduced. Can do. When the resin layer is formed on the support, the thickness of the resin layer is, for example, preferably 50 μm or less, more preferably 20 μm or less, further preferably 10 μm or less, and particularly preferably 5 μm or less.

  As the support, a transparent substrate such as a resin plate, a resin film, or a glass plate is preferably used. As the resin plate or resin film used for the support, for example, those formed from the resin components described above are preferably used. From the viewpoint of increasing the heat resistance of the optical filter, it is preferable to use a glass substrate as the support, and the optical filter formed in this way can be mounted on an electronic component by, for example, solder reflow. Further, since the glass substrate is not easily cracked or warped even when exposed to a high temperature, it is easy to ensure adhesion with the resin layer. When a glass substrate is used as the support, a binder layer formed of, for example, a silane coupling agent may be provided between the support and the resin layer, thereby improving the adhesion between the resin layer and the glass substrate. Can do. In addition, even if it includes a silane coupling agent as an adhesive improvement agent in the resin composition which forms a resin layer, the adhesiveness of a resin layer and a glass substrate can be improved.

  The thickness of the support (substrate) is, for example, preferably 0.05 mm or more, more preferably 0.1 mm or more from the viewpoint of securing strength, and preferably 0.4 mm or less, and 0.3 mm from the viewpoint of thinning. The following is more preferable.

  In the resin layer formed from the resin composition, a protective layer made of the same or different resin as the resin layer may be laminated as the second resin layer. By providing the protective layer, the durability (decomposition resistance) of the squarylium compound contained in the resin layer can be enhanced. The protective layer may be provided only on one side of the resin layer, or may be provided on both sides. When the resin layer is provided on the support, the protective layer is preferably provided on the surface of the resin layer opposite to the support.

  In the case of forming an optical filter from the resin composition of the present invention, the optical filter is a layer having antireflection and antiglare properties (antireflection film) for reducing the reflection of a fluorescent lamp or the like, and a layer having scratch resistance. In addition, a transparent substrate having other functions may be included.

  The optical filter may have a near-infrared reflective film (for example, a reflective film having a wavelength range of 700 nm to 800 nm) on the resin layer. It is preferable that the near-infrared reflective film is provided on the light incident side with respect to the resin layer. If the optical filter is provided with a near-infrared reflective film, the near-infrared light can be further cut from the transmitted light of the optical filter. Note that the near-infrared reflective film may have an ultraviolet reflection function.

  The near-infrared reflective film or antireflection film (visible light antireflection film) can be composed of a dielectric multilayer film in which high refractive index material layers and low refractive index material layers are alternately laminated. Therefore, when providing such a function to an optical filter, the optical filter preferably has a dielectric multilayer film. As a material constituting the high refractive index material layer, a material having a refractive index of 1.7 or more can be used, and a material having a refractive index range of 1.7 to 2.5 is usually selected. Examples of the material constituting the high refractive index material layer include oxides such as titanium oxide, zinc oxide, zirconium oxide, lanthanum oxide, yttrium oxide, indium oxide, niobium oxide, tantalum oxide, tin oxide, and bismuth oxide; silicon nitride Nitrides such as oxides, mixtures of the nitrides, and those doped with metals such as aluminum and copper and carbon (for example, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO)), etc. It is done. As a material constituting the low refractive index material layer, a material having a refractive index of 1.6 or less can be used, and a material having a refractive index range of 1.2 to 1.6 is usually selected. Examples of the material constituting the low refractive index material layer include silicon dioxide (silica), alumina, lanthanum fluoride, magnesium fluoride, and aluminum hexafluoride sodium.

  The optical filter may also include an aluminum vapor deposition film, a noble metal thin film, a resin film in which metal oxide fine particles containing indium oxide as a main component and containing a small amount of tin oxide are dispersed.

  The thickness of the optical filter is preferably 1 mm or less, for example. Thereby, for example, it is possible to sufficiently meet the demand for downsizing of the image sensor. The thickness of the optical filter is more preferably 500 μm or less, further preferably 300 μm or less, still more preferably 150 μm or less, and preferably 30 μm or more, more preferably 50 μm or more.

  The optical filter can be used as one of constituent members of sensors such as an image sensor (imaging device), an illuminance sensor, and a proximity sensor. For example, an image sensor is used as an electronic component that converts light of a subject into an electrical signal and outputs the signal, and includes a charge coupled device (CCD), a complementary metal-oxide semiconductor (CMOS), and the like. The image sensor can be used for a mobile phone camera, a digital camera, an in-vehicle camera, a surveillance camera, a display element (LED or the like), and the like. The sensor includes one or more of the optical filters described above, and may further include other filters (for example, a visible light cut filter, an infrared cut filter, an ultraviolet cut filter, etc.) or a lens as necessary.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, and is implemented with appropriate modifications within a range that can meet the purpose described above and below. Any of these may be included in the technical scope of the present invention.

(1) Synthesis of compound (1-1) Synthesis of squarylium compound A In a 300 mL four-necked flask, 46 g of dimethylformamide, 13 g of potassium carbonate, 3.92 g of 7-nitro-1,2,3,4-tetrahydroquinoline (0 0.022 mol) and 10 g of iodomethane were charged, and the mixture was allowed to react at 40 ° C. for 4 hours while stirring with a stirring blade under a nitrogen flow (10 mL / min). After completion of the reaction, the resulting reaction solution was added to a beaker containing 300 mL of aqueous potassium hydroxide and 300 mL of ethyl acetate while stirring. The aqueous solution was alkaline. After stirring for a while, the organic phase was extracted with a separatory funnel, and magnesium sulfate (anhydrous) was added to the extracted organic phase for dehydration. After the solid matter (inorganic content) was filtered off from the organic phase, the solvent was distilled off using an evaporator. Thereafter, silica gel column chromatography was appropriately used, and concentration and vacuum drying were performed to obtain 3.02 g of intermediate A1. The yield based on the starting 7-nitro-1,2,3,4-tetrahydroquinoline was 71.4 mol%.

  Next, 1.40 g (0.0073 mol) of the intermediate A1 obtained above and 6.0 g of concentrated hydrochloric acid (hydrochloric acid concentration 36% by weight) were placed in a 30 mL two-necked flask under nitrogen flow (5 mL / min). While stirring using a magnetic stirrer, a solution prepared by dissolving 5.5 g of tin chloride dihydrate in 5.5 g of concentrated hydrochloric acid (hydrochloric acid concentration 36% by weight) was added little by little while paying attention to the heat of reaction. . After the addition, the mixture was stirred at room temperature for about 3 hours. Thereafter, the obtained reaction solution was added to a beaker containing 100 g of pure water and 100 g of ethyl acetate while stirring. Potassium hydroxide solution was added little by little, and after stirring for a while when the pH of the aqueous solution reached about 10, the organic phase was extracted with a separatory funnel, and magnesium sulfate (anhydrous) was added to the extracted organic phase. And dehydrated. After filtering solids (inorganic content) from this organic phase, after concentrating the solvent using an evaporator, using silica gel column chromatography (developing solvent: ethyl acetate) as appropriate, and performing concentration and vacuum drying, 0.8 g of intermediate A2 was obtained. The yield based on the intermediate A1 was 67.7 mol%.

  Next, 0.84 g (0.0052 mol) of intermediate A2 and 80 g of ultra-dehydrated chloroform were placed in a 100 mL three-necked flask and stirred with a magnetic stirrer under nitrogen flow (5 mL / min). .58 g (0.0156 mol) and 0.69 g (0.0026 mol) of dodecanedioyl dichloride were added and reacted at room temperature for 12 hours. After completion of the reaction, the resulting reaction solution was added to ion exchange water and extracted with ethyl acetate. The obtained organic phase was concentrated with an evaporator, and the concentrated solution was purified by silica gel column chromatography (developing solvent: ethyl acetate) to obtain 0.40 g of intermediate A3. The yield based on the intermediate A2 was 47.4%.

  Next, 0.26 g (0.0005 mol) of intermediate A3, 0.057 g (0.0005 mmol) of squaric acid, 5 g of 1-butanol and 5 g of toluene were placed in a 30 mL two-necked flask under nitrogen flow (5 mL / min). ), The mixture was stirred using a magnetic stirrer, and the reaction was carried out for 3 hours under reflux conditions while removing the eluted water using a Dean Stark apparatus. After completion of the reaction, the reaction mixture was cooled to room temperature and the precipitate was filtered off. The precipitate separated by filtration was washed with methanol, only the precipitate was filtered again, and the obtained cake (solid) was purified by column chromatography using alumina (developing solvent: chloroform). The obtained purified product was dried at 60 ° C. for 12 hours using a vacuum dryer to obtain 0.01 g of the target product, squarylium compound A. The yield based on squaric acid was 3.34 mol%.

(1-2) Synthesis of squarylium compounds B and C According to the synthesis example of squarylium compound A, the squarylium compound B shown in Table 1 was synthesized, and according to the method described in JP-A-1-228960, The squarylium compound C shown in Table 1 was synthesized.

(2) Evaluation Using a spectrophotometer (“UV-1800” manufactured by Shimadzu Corporation), the absorbance spectrum of each of the squarylium compounds A to C is measured at a measurement pitch of 1 nm, and the absorbance in a wavelength range of 300 nm to 1100 nm is obtained. It was. Absorbance measurement was performed with the squarylium compound dissolved in chloroform, and a chloroform solution was used as a baseline. Further, the concentration of the squarylium compound in the chloroform solution was adjusted so that the absorbance at the maximum absorption wavelength was 1 ± 0.003. For the absorption spectrum of each squarylium compound thus measured, the maximum wavelength λmax of the maximum absorption peak, the slope S _{0.5 at} an absorbance 0.5 shorter than the maximum wavelength λmax, and the average absorbance in the wavelength range of 450 nm to 600 nm, respectively. Asked. The slope S _0.5 is expressed by the equation: S _0.5 = (0 _...) , Where λ _0.55 is the wavelength at which the absorbance is 0.55 on the shorter wavelength side than λmax, and λ _0.45 is the wavelength at which the absorbance is 0.45. 55−0.45) / (λ _0.55 −λ _0.45 ). The average absorbance in the wavelength range of 450 nm to 600 nm was determined by averaging the absorbance values at 151 points measured at a 1 nm pitch in the wavelength range of 450 nm to 600 nm. The results are shown in Table 2, and the respective absorption spectra of squarylium compound A and squarylium compound C are shown in FIG.

The squarylium compound A had a large slope S _0.5 value at an absorbance 0.5 on the short wavelength side of the maximum absorption peak, and showed a sharper absorption peak than the squarylium compounds B and C. In addition, the average absorbance in the wavelength range of 450 nm to 600 nm was less than 0.01, indicating a high visible light transmittance. The squarylium compound A can sharpen the waveform of the absorption peak in the red to near-infrared region, and can realize more selective light absorption.

  The squarylium compound of the present invention can be used for, for example, electronic parts such as a mobile phone camera, a digital camera, an in-vehicle camera, a surveillance camera, a display element (LED, etc.), security ink, and the like.

Claims (9)

A squarylium compound represented by the following formula (1):

[In Formula (1),
R ¹ and R ⁴ are connected to each other,
R ^2, R ^3, R ⁵ and R ⁶ each independently represent a hydrogen atom, an organic group or a polar functional group,
Ring A and Ring B are each independently a 6-membered or more non-aromatic hydrocarbon ring which may have a substituent or a 6-membered or more non-aromatic heterocyclic ring which may have a substituent. Represent. ] The squarylium compound according to claim 1, wherein R ¹ represents a group represented by the following formula (2), and R ⁴ represents a group represented by the following formula (3).
—NH—R ⁷ (2)
—NH—R ⁸ (3)
[In Formula (2) and Formula (3), R ⁷ and R ⁸ are linked to each other. ] The squarylium compound according to claim 1 or 2 represented by the following formula (5).

[In Formula (5), R ² , R ³ , R ⁵ , R ⁶ , Ring A and Ring B represent the same meaning as described above, and X ¹ and X ² each independently represent a carbonyl group or a sulfonyl group. , Y represents an organic linking group. ] X ¹ and X ² represent a carbonyl group, and Y represents an alkylene group which may have a substituent, an arylene group which may have a substituent, or a hetero which may have a substituent. The squarylium compound according to claim 3, which represents an arylene group or a linking group in which these groups are bonded by a single bond, -O-, -CO-, -S-, or -NH-. The squarylium according to any one of claims 1 to 4, wherein each of R ² , R ³ , R ⁵ and R ⁶ independently represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an amino group or a hydroxyl group. Compound. When the absorption spectrum in the wavelength range of 450 nm to 1100 nm measured in chloroform has an absorbance at the maximum wavelength λmax of the maximum absorption peak as 1, the slope at the absorbance 0.5 on the shorter wavelength side than the maximum wavelength λmax is 3. A squarylium compound characterized by being 25 × 10 ⁻² nm ⁻¹ or more.   A resin composition comprising the squarylium compound according to any one of claims 1 to 6 and a resin component.   An optical filter comprising the resin composition according to claim 7.   A sensor comprising the optical filter according to claim 8.

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