Pyran derivatives, manufacturing methods, and photoelectric conversion elements

Abstract

To provide a compound exhibiting a high external quantum efficiency which is suitable as a photoelectric conversion material for blue light, a method for simply synthesizing the compound and a photoelectric conversion element containing the compound.SOLUTION: There is provided a pyran derivative represented by the formula (1). In the formula, R1 to R6 each independently represent H and an alkyl group having 1 to 4 carbon atoms; X1 and X2 each independently represent H, a halogen atom, a trifluoromethyl group or a cyano group and at least one of which is a cyano group; Ar1 represents an aryl group having 6 to 18 carbon atoms or a heteroaromatic group having 2 to 5 carbon atoms and the aryl group and heteroaromatic group may be substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, a dialkylamino group having 2 to 5 carbon atoms and a diarylamino group having 12 to 18 carbon atoms; Ar2 represents a heteroaromatic group such as a benzofuran group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to pyran derivatives and methods for producing the same. [Background technology]

[0002] Photoelectric conversion elements are used in sensors such as light sensors and image sensors, as well as in photovoltaic devices such as solar cells. Photoelectric conversion elements using organic photoelectric conversion materials are disclosed in Patent Document 1, among others.

[0003] Silicon semiconductor elements are widely used as photoelectric conversion elements, and silicon photodiodes are primarily used as image sensors. Since such silicon photodiodes are sensitive across the entire visible light range, a color filter with RGB colors arranged in a mosaic pattern is placed on top of it, and each pixel is assigned as a light-receiving area for each of the RGB colors to perform color imaging. In this method, the loss of incident light in the color filter results in low light utilization efficiency, which is a concern as it may hinder the improvement of image sensor sensitivity. Therefore, an image sensor in which organic photoelectric conversion films of each RGB color are stacked (hereinafter referred to as a stacked organic image sensor) has been proposed (see, for example, Non-Patent Document 1). Compared to the method using a color filter, this method eliminates light loss due to the color filter and improves light utilization efficiency by several times, making it advantageous for miniaturizing pixels in devices such as cameras, and is expected to be used in high-sensitivity devices.

[0004] For photoelectric conversion films in stacked organic image sensors, high external quantum efficiency is required in the wavelength range corresponding to each color. Specifically, in the case of the B layer (blue light photoelectric conversion film), high external quantum efficiency is required in the blue light region of 400-500 nm.

[0005] Patent documents 1 to 3 describe blue photoelectric conversion elements containing perylene derivatives, coumarin derivatives, dipyromethene derivatives, etc., but none of them are the same as the photoelectric conversion elements containing the pyran derivative of the present invention. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2020 / 195935 [Patent Document 2] International Publication No. 2020 / 196029 [Patent Document 3] International Publication No. 2021 / 029223 [Non-patent literature]

[0007] [Non-Patent Document 1] Japanese Journal of Applied Physics, 2011, Vol. 50, p. 24103 [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a compound that exhibits high external quantum efficiency and is suitable as a photoelectric conversion material for blue light, a method for easily synthesizing the compound, and a photoelectric conversion element containing the compound. [Means for solving the problem]

[0009] As a result of diligent research to solve the above problems, the inventors of this invention have discovered that a photoelectric conversion element containing a novel pyran derivative exhibits high external quantum efficiency in the blue light wavelength range, and have completed the present invention.

[0010] In other words, the present invention is [1] A pyran derivative represented by formula (1).

[0011] [ka]

[0012] In formula (1), R1 ~R 6 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. X 1 and X 2 each independently represents a hydrogen atom, a halogen atom, a trifluoromethyl group or a cyano group, and at least one of them is a cyano group. Ar 1 represents an aryl group having 6 to 18 carbon atoms or a heteroaromatic group having 2 to 5 carbon atoms, and the aryl group and the heteroaromatic group may be substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, a dialkylamino group having 2 to 5 carbon atoms, and a diarylamino group having 12 to 18 carbon atoms. The dialkylamino group and the diarylamino group may form a ring integrally with two alkyl groups or aryl groups containing a nitrogen atom. Further, the dialkylamino group and the diarylamino group may form a ring integrally with two alkyl groups or aryl groups bonded through an oxygen atom or a sulfur atom and containing a nitrogen atom. Ar 2 represents a heteroaromatic group represented by formula (2).

[0013] [Chemical formula]

[0014] (In the formula, E represents an oxygen atom, a sulfur atom or a selenium atom. R 1a ~R 5a each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 18 carbon atoms or a heteroaromatic group having 3 to 12 carbon atoms, and the aryl group and the heteroaromatic group may be substituted with one or more alkyl groups having 1 to 4 carbon atoms or halogen atoms. * represents a bonding site.); [2] X 1 and X 2 are cyano groups, and the pyran derivative according to [1]; [3] R 1a ~R 5aHowever, the pyran derivative according to [1] or [2] is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms; [4] A pyran derivative according to any one of the above [1] to [3], wherein E is an oxygen atom; [5] R 1 ~R 6 A pyran derivative according to any one of the above [1] to [4], wherein is a hydrogen atom; [6] Ar 1 The pyran derivative according to any one of the above [1] to [5], wherein the aryl group having 6 to 18 carbon atoms is substituted with one or more dialkylamino groups having 2 to 5 carbon atoms, and the two alkyl groups of the dialkylamino group may be bonded via an oxygen atom or a sulfur atom and contain a nitrogen atom to form a ring; [7] Formula (3)

[0015] [ka]

[0016] (In the formula, R 1 ~R 5 Each of these independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1 and X 2 Each of these independently represents a hydrogen atom, a halogen atom, a trifluoromethyl group, or a cyano group, and at least one of them is a cyano group. 1represents an aryl group having 6 to 18 carbon atoms or a heteroaromatic group having 2 to 5 carbon atoms, and the aryl group and heteroaromatic group may be substituted with one or more substituents selected from the group consisting of alkyl groups having 1 to 4 carbon atoms, aryl groups having 6 to 10 carbon atoms, dialkylamino groups having 2 to 5 carbon atoms, and diarylamino groups having 12 to 18 carbon atoms. The dialkylamino group and diarylamino group may form a ring containing a nitrogen atom, with two alkyl or aryl groups bonded together via an oxygen or sulfur atom. The pyran compound represented by ) and formula (4)

[0017] [ka]

[0018] [In the formula, Ar 2 is equation (5)

[0019] [ka]

[0020] (In the formula, E represents an oxygen atom, a sulfur atom, or a selenium atom. R 1a ~R 5a Each of these independently represents a hydrogen atom, a halogen atom, a C1-C4 alkyl group, a C6-C18 aryl group, or a C3-C12 heteroaromatic group, and the aryl group and heteroaromatic group may be substituted with one or more C1-C4 alkyl groups or halogen atoms. * represents a bonding site. ) represents a heteroaromatic group indicated by R 6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The method is characterized by reacting with a carbonyl compound represented by formula (1)

[0021] [ka]

[0022] (In the formula, R 1 ~R 6 Ar 1 Ar 2 , X 1 and X 2 The above has the same meaning as above.) Method for producing pyran derivatives as shown; [8] A method for producing the pyran derivative described in [7], characterized by reacting a pyran compound with a carbonyl compound in the presence of an acid; [9] A method for producing the pyran derivative described in [7], characterized by reacting a pyran compound with a carbonyl compound in the presence of a base;

[10] A photoelectric conversion element comprising a pyran derivative as described in any one of the above items [1] to [6];

[11] A photoelectric conversion element comprising a pyran derivative according to any one of the above [1] to [6] in a photoelectric conversion layer;

[12] A photoelectric element according to

[11] , further comprising a fullerene derivative in the photoelectric conversion layer;

[13] Fullerene derivatives are C 60 or C 70 The present invention relates to the photoelectric conversion element described in

[12] above. [Effects of the Invention]

[0023] Since the pyran derivative (1) of the present invention exhibits high external quantum efficiency in the blue light region, it is expected to be applied as an organic electronic material, such as a material for blue light organic photoelectric conversion elements. [Modes for carrying out the invention]

[0024] The present invention will be described in detail below.

[0025] In the present invention, the pyran derivative (1) and the heteroaromatic group (2) R 1 ~R 6 , X 1 , X 2 Ar 1Ar 2 , E and R 1a ~R 5a Let's explain the definition.

[0026] R 1 ~R 6 The C1-C4 alkyl group represented by can be linear, branched, or cyclic alkyl groups. Specifically, examples include methyl, ethyl, propyl, 2-methylpropyl, isopropyl, cyclopropyl, butyl, 2-butyl, tert-butyl, or cyclobutyl groups. A methyl group is preferred because it facilitates the synthesis of pyran derivative (1).

[0027] R 1 ~R 6 As such, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred, in terms of ease of synthesis of the pyran derivative (1).

[0028] X 1 and X 2 Examples of halogen atoms represented by include fluorine, chlorine, bromine, or iodine atoms, with fluorine being preferred because it exhibits excellent light absorption properties in the pyran derivative (1).

[0029] X 1 and X 2 In terms of the excellent light absorption properties of the pyran derivative (1), a fluorine atom, a trifluoromethyl group, or a cyano group is preferred, and a cyano group is even more preferred.

[0030] Ar 1The aryl group having 6 to 18 carbon atoms represented by is not particularly limited, but specifically includes phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, 3,5-terphenylyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenantrenyl group, 2-phenantrenyl group, 3-phenantrenyl group, 4-phenantrenyl group, 9-phenantrenyl group, 1 Examples include -fluorenyl group, 2-fluorenyl group, 3-fluorenyl group, 4-fluorenyl group, 9,9-dimethyl-9H-fluoren-1-yl group, 9,9-dimethyl-9H-fluoren-2-yl group, 9,9-dimethyl-9H-fluoren-3-yl group, 9,9-dimethyl-9H-fluoren-4-yl group, 1-pyrenyl group, 2-pyrenyl group, 9-pyrenyl group, 1-triphenylenyl group, or 2-triphenylenyl group. Phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, 9,9-dimethyl-9H-fluoren-1-yl group, 9,9-dimethyl-9H-fluoren-2-yl group, 9,9-dimethyl-9H-fluoren-3-yl group, or 9,9-dimethyl-9H-fluoren-4-yl group are preferred in terms of ease of synthesis of pyran derivative (1).

[0031] Ar 1 The heteroaromatic group having 2 to 5 carbon atoms represented by is not particularly limited, but specifically, examples include 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-furanyl group, 3-furanyl group, 2-thiophenyl group, 3-thiophenyl group, 1-pyrrolyl group, 2-(1-methyl)pyrrolyl group, 3-(1-methyl)pyrrolyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 1-imidazolyl group, 2-(1-methyl)imidazolyl group, 4-(1-methyl)imidazolyl group, 5-(1-methyl)imidazolyl group, triazolyl group, etc. The 2-furanyl group or the 2-thiophenyl group is preferred because it facilitates the synthesis of pyran derivative (1).

[0032] Ar 1The aryl group having 6 to 18 carbon atoms and the heteroaromatic group having 2 to 5 carbon atoms represented by the formula may be substituted with one or more substituents selected from the group consisting of alkyl groups having 1 to 4 carbon atoms, aryl groups having 6 to 10 carbon atoms, dialkylamino groups having 2 to 5 carbon atoms, and diarylamino groups having 12 to 18 carbon atoms. The alkyl group having 1 to 4 carbon atoms may be linear, branched, or cyclic alkyl groups. Specifically, examples include methyl, ethyl, propyl, 2-methylpropyl, isopropyl, cyclopropyl, butyl, 2-butyl, tert-butyl, and cyclobutyl groups, with the methyl group being preferred because it facilitates the synthesis of pyran derivative (1). The aryl group having 6 to 10 carbon atoms may be phenyl, 1-naphthyl, or 2-naphthyl groups, with the phenyl group being preferred because it facilitates the synthesis of pyran derivative (1). The two alkyl groups in the dialkylamino group having 2 to 5 carbon atoms may be linear or branched. Furthermore, the two alkyl groups may form a ring together, or they may be bonded via an oxygen atom or a sulfur atom to form a ring together. Specifically, examples include dimethylamino group, diethylamino group, 1-pyrrolidinyl group, 1-piperidinyl, 4-morpholinyl group, 4-thiomorpholinyl group, etc., and dimethylamino group, 1-pyrrolidinyl group, 1-piperidinyl group, or 4-morpholinyl group are preferred because they facilitate the synthesis of pyran derivative (1). As for the C12-C18 diarylamino group, the two aryl groups may form a ring together with a nitrogen atom, or they may be bonded via an oxygen atom or a sulfur atom to form a ring together with a nitrogen atom. Specifically, examples include diphenylamino group, 1-naphthyl(phenyl)amino group, 2-naphthyl(phenyl)amino group, or 9-9H-carbazoyl group, 10-10H-phenoxazinyl group, 10-10H-phenothiazinyl group, etc. Diphenylamino group or 9-9H-carbazoyl group are preferred because they facilitate the synthesis of pyran derivative (1).

[0033] Ar 1As for the ease of synthesizing pyran derivative (1), phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, 9,9-dimethyl-9H-fluoren-1-yl group, 9,9-dimethyl-9H-fluoren-2-yl group, 9,9-dimethyl-9H-fluoren-3-yl group, 9,9-dimethyl-9H-fluoren-4-yl group, 2-methylphenyl group, 3-methylphenyl group, 4- Methylphenyl group, 2-(5-methyl)furanyl group, 2-(5-methyl)thiophenyl group, 2-(5-phenyl)furanyl group, 2-(5-phenyl)thiophenyl group, 4-(dimethylamino)phenyl group, 4-(diethylamino)phenyl group, 4-(1-pyrrolidinyl)phenyl group, 4-(1-piperidinyl)phenyl group, 4-(4-morpholinyl)phenyl group, 4-(dimethylamino)-1-naphthyl group, 6-(dimethylamino)2 - Naphthyl group, 4-(diphenylamino)phenyl group, 4-{1-naphthyl(phenyl)amino}phenyl group or 4-(9-9H-carbazoyl)phenyl group are preferred, and 2-(5-phenyl)furanyl group, 2-(5-phenyl)thiophenyl group, 4-(dimethylamino)phenyl group, 4-(diethylamino)phenyl group, 4-(1-pyrrolidinyl)phenyl group, 4-(1-piperidinyl)phenyl group, 4-(4-morpholinyl)phenyl group A nyl group, 4-(dimethylamino)-1-naphthyl group, 6-(dimethylamino)2-naphthyl group, 4-(diphenylamino)phenyl group, 4-{1-naphthyl(phenyl)amino}phenyl group, or 4-(9-9H-carbazoyl)phenyl group is more preferred, and a 2-(5-phenyl)thiophenyl group, 4-(dimethylamino)phenyl group, 4-(1-piperidinyl)phenyl group, or 4-(4-morpholinyl)phenyl group is particularly preferred.

[0034] E represents an oxygen atom, a sulfur atom, or a selenium atom. An oxygen atom or a sulfur atom is preferred, and an oxygen atom is even more preferred, because it facilitates the synthesis of the pyran derivative (1).

[0035] R 1a ~R 5a X is a halogen atom that can be represented as 1 and X 2Similar to the halogen atoms exemplified above, fluorine atoms are preferred because they provide excellent light absorption properties for the pyran derivative (1).

[0036] R 1a ~R 5a The alkyl group with 1 to 4 carbon atoms represented by R 1 ~R 6 Similar alkyl groups having 1 to 4 carbon atoms as exemplified above can be given, and a methyl group is preferred because it facilitates the synthesis of pyran derivative (1).

[0037] R 1a ~R 5a As an aryl group having 6 to 18 carbon atoms, represented by Ar 1 Similar to the aryl groups with 6 to 18 carbon atoms exemplified above, the phenyl group is preferred because it facilitates the synthesis of pyran derivative (1).

[0038] R 1a ~R 5a The heteroaromatic groups with 3 to 12 carbon atoms represented by are not particularly limited, but specifically include 2-furanyl group, 3-furanyl group, 2-thienyl group, 3-thienyl group, 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 2-benzofuranyl group, 3-bensofuranyl group, 2-benzothienyl group, 3-bensofuranyl group, 1- Examples include indolyl group, 2-indolyl group, 3-indolyl group, 1-carbazoyl group, 2-carbazoyl group, 3-carbazoyl group, 4-carbazoyl group, 9-carbazoyl group, dibenzofuran-2-yl group, dibenzofuran-3-yl group, dibenzofuran-4-yl group, dibenzothiophene-2-yl group, dibenzothiophene-3-yl group, or dibenzothiophene-4-yl group. 2-pyridyl group, 3-pyridyl group, or 4-pyridyl group are preferred because they facilitate the synthesis of pyran derivative (1).

[0039] R 1a ~R 5aThe aryl group having 6 to 18 carbon atoms and the heteroaromatic group having 3 to 12 carbon atoms represented by may be substituted with one or more alkyl groups or halogen atoms having 1 to 4 carbon atoms. The alkyl groups having 1 to 4 carbon atoms include R 1 ~R 6 Examples of alkyl groups having 1 to 4 carbon atoms as exemplified above can be given, and the methyl group is preferred because it facilitates the synthesis of pyran derivative (1). The halogen atom is X 1 and X 2 Similar to the halogen atoms exemplified above, fluorine atoms are preferred because they facilitate the synthesis of pyran derivative (1).

[0040] R 1a ~R 5a In terms of ease of synthesis, hydrogen atoms, methyl groups, phenyl groups, 2-pyridyl groups, 3-pyridyl groups, 4-pyridyl groups, 2-methylphenyl groups, 3-methylphenyl groups, 4-methylphenyl groups, 2-fluorophenyl groups, 3-fluorophenyl groups, or 4-fluorophenyl groups are preferred, hydrogen atoms, methyl groups, or phenyl groups are more preferred, and hydrogen atoms are particularly preferred.

[0041] The pyran derivative (1) of the present invention is not particularly limited, and specific examples include compounds having the structures shown in 1-1 to 1-51 below. In this specification, Me and Et represent a methyl group and an ethyl group, respectively.

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045] Of the compounds represented by 1-1 to 1-51, the pyran derivative (1) of the present invention is preferably the compound represented by 1-16, 1-17, 1-18, 1-19, 1-20, 1-21, 1-22, 1-23, 1-24, 1-25, 1-26, 1-27, 1-35, 1-37, 1-39, 1-40, or 1-41, which are easy to synthesize, and more preferably the compound represented by 1-17, 1-18, 1-21, or 1-22.

[0046] The pyran ring of the compound represented by formula (1), and Ar 1 and Ar 2 The two double bonds substituted by each have E and Z isomers, respectively. For convenience, only the E isomer is shown in this specification, but the invention is not limited to the E isomer, and the Z isomer is also included in the pyran derivative (1) of the present invention.

[0047] Next, the method for producing the pyran derivative (1) of the present invention (hereinafter referred to as the "production method of the present invention") will be described.

[0048] The pyran derivative (1) of the present invention can be produced by step 1 shown in the following reaction formula.

[0049] [ka]

[0050] (In the formula, R 1 ~R 5 Each of these independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1 and X 2 Each of these independently represents a hydrogen atom, a halogen atom, a trifluoromethyl group, or a cyano group, and at least one of them is a cyano group. 1The aryl group represents an aryl group having 6 to 18 carbon atoms or a heteroaromatic group having 2 to 5 carbon atoms, and the aryl group and heteroaromatic group may be substituted with one or more substituents selected from the group consisting of alkyl groups having 1 to 4 carbon atoms, aryl groups having 6 to 10 carbon atoms, dialkylamino groups having 2 to 5 carbon atoms, and diarylamino groups having 12 to 18 carbon atoms. The dialkylamino group and diarylamino group may form a ring by having two alkyl or aryl groups bonded together with a nitrogen atom. Alternatively, the dialkylamino group and diarylamino group may form a ring by having two alkyl or aryl groups bonded together with an oxygen or sulfur atom, including a nitrogen atom. Ar 2 is equation (5)

[0051] [ka]

[0052] (In the formula, E represents an oxygen atom, a sulfur atom, or a selenium atom. R 1a ~R 5a Each of these independently represents a hydrogen atom, a halogen atom, a C1-C4 alkyl group, a C6-C18 aryl group, or a C3-C12 heteroaromatic group, and the aryl group and heteroaromatic group may be substituted with one or more C1-C4 alkyl groups or halogen atoms. * represents a bonding site. ) represents a heteroaromatic group indicated by ). Step 1 is a step in which a pyran compound (3) and a carbonyl compound (4) are reacted to produce the pyran derivative (1) of the present invention.

[0053] The substituents in the pyran compound (3) used in step 1 are the same as those of the pyran derivative shown in formula (1).

[0054] Examples of the pyran compound (3) used in step 1 include, for example, compounds with the structures shown in 3-1 to 3-34 below, but the present invention is not limited to these.

[0055] [ka]

[0056] [ka]

[0057] Of the compounds shown in 3-1 to 3-34, compounds 3-16, 3-17, 3-18, 3-19, 3-20, 3-21, 3-22, 3-23, 3-24, 3-25, 3-26, or 3-27 are preferred due to their ease of synthesis, and compounds 3-17, 3-18, 3-21, or 3-22 are even more preferred. The pyran compound (3) can be produced by general methods well known to those skilled in the art, for example, by following the method disclosed in the Journal of the American Chemical Society, 2009, Vol. 131, p. 14043. Alternatively, commercially available products may be used.

[0058] Examples of substituents in the carbonyl compound (4) used in step 1 include those similar to those of the pyran derivative shown in formula (1).

[0059] Examples of carbonyl compounds (4) used in step 1 include, for example, compounds with the structures shown in 4-1 to 4-17 below.

[0060] [ka]

[0061] Of the compounds shown in 4-1 to 4-17, those shown in 4-1, 4-2, 4-5, 4-6, or 4-7 are preferred due to their ease of synthesis, and the compound shown in 4-1 is even more preferred. The carbonyl compound (4) can be produced by general methods well known to those skilled in the art, for example, by following the method disclosed in Chemical Communications, 2017, Vol. 53, p. 7545. Alternatively, commercially available products may be used.

[0062] There are no particular restrictions on the molar ratio of pyran compound (3) and carbonyl compound (4) used in step 1. However, for good yield, the molar ratio of pyran compound (3) to carbonyl compound (4) is preferably in the range of 1:0.1 to 1:10, and for good reaction yield, it is even more preferably in the range of 1:0.5 to 1:2.

[0063] Step 1 can be carried out in a solvent. There are no particular restrictions on the solvent that can be used; any solvent that does not inhibit the reaction is acceptable. Specifically, such solvents include ethers such as diisopropyl ether, dibutyl ether, cyclopentyl methyl ether (CPME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, and dimethoxyethane; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, and tetralin; aliphatic hydrocarbons such as pentane, hexane, heptane, octane, and cyclohexane; carbonate esters such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and 4-fluoroethylene carbonate; ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, and γ-L Examples of solvents include esters such as kutone; amides such as N,N-dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP); ureas such as N,N,N',N'-tetramethylurea (TMU) and N,N'-dimethylpropyleneurea (DMPU); dimethyl sulfoxide (DMSO); alcohols such as methanol, ethanol, isopropyl alcohol, butanol, octanol, benzyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and 2,2,2-trifluoroethanol; and nitriles such as acetonitrile and benzonitrile. These can be mixed in any ratio. There are no particular restrictions on the amount of solvent used. Aliphatic hydrocarbons, alcohols, or nitriles are preferred in terms of the good reaction yield of the pyran derivative (1) of the present invention, and acetonitrile is more preferred.

[0064] Step 1 can be carried out in the presence of an acid to accelerate the reaction. The acid used is not particularly limited, but may be either an inorganic or organic acid. Examples of inorganic acids include hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, and nitric acid, while examples of organic acids include carboxylic acids such as acetic acid, propionic acid, and benzoic acid, and sulfonic acids such as p-toluenesulfonic acid, methanesulfonic acid, and trifluoromethanesulfonic acid. Hydrochloric acid, sulfuric acid, or p-toluenesulfonic acid are preferred in that they yield a good reaction yield of the pyran derivative (1) of the present invention, and p-toluenesulfonic acid is more preferred.

[0065] There are no particular restrictions on the molar equivalent of the acid used in step 1, but it is preferable that the molar ratio of carbonyl compound (4) to acid be in the range of 1:0.01 to 1:100 for good yield, and more preferably in the range of 1:0.1 to 1:10 for good reaction yield.

[0066] Step 1 can be carried out in the presence of a base to accelerate the reaction. The base used is not particularly limited, but can be either an inorganic or organic base. Examples of inorganic bases include metal hydroxides such as sodium hydroxide, potassium hydroxide, and calcium hydroxide; metal carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, and cesium carbonate; metal acetates such as potassium acetate and sodium acetate; metal phosphates such as potassium phosphate and sodium phosphate; metal hydrides such as sodium hydride, potassium hydride, and calcium hydride; and metal alkyl oxides such as sodium methoxide, potassium methoxide, sodium ethoxide, potassium isopropyl oxide, and potassium tert-butoxide. Examples of organic bases include tertiary alkylamines such as trimethylamine, triethylamine, diisopropylethylamine, and tributylamine; cyclic azines such as pyridine, pyrazine, and quinoline; and secondary cyclic amines such as pyrrolidine, piperidine, piperazine, N-methylpiperazine, and morpholine. In terms of the good reaction yield of the pyran derivative (1) of the present invention, organic bases such as triethylamine, piperidine, piperazine, or N-methylpiperazine are preferred, and piperidine or N-methylpiperazine are more preferred.

[0067] There are no particular restrictions on the molar equivalent of the base used in step 1, but it is preferable that the molar ratio of carbonyl compound (4) to base be in the range of 1:0.001 to 1:100 for good yield, and more preferably in the range of 1:0.01 to 1:10 for good reaction yield.

[0068] There are no particular restrictions on the reaction temperature when carrying out step 1. It can usually be carried out at a temperature appropriately selected from the range of -80°C to 200°C. However, it is preferable to carry out the step at a temperature appropriately selected from the range of 0°C to 150°C, and more preferably at a temperature appropriately selected from the range of 10°C to 140°C, in order to obtain a good reaction yield of the pyran derivative (1) of the present invention.

[0069] The pyran derivative (1) of the present invention can be obtained by performing ordinary treatment after the completion of the reaction in Step 1. If necessary, it may be purified by recrystallization, column chromatography, sublimation, preparative HPLC, or the like.

[0070] Furthermore, a photoelectric conversion device (hereinafter referred to as "the photoelectric conversion device of the present invention") including the pyran derivative (1) of the present invention will be described. The photoelectric conversion device of the present invention includes a substrate, a negative electrode layer, a photoelectric conversion layer, and a positive electrode layer. Further, a hole transport layer and / or an electron blocking layer may be provided between the negative electrode layer and the photoelectric conversion layer, and an electron transport layer and / or a hole blocking layer may be provided between the positive electrode layer and the photoelectric conversion layer, if necessary.

[0071] In the photoelectric conversion device of the present invention, the pyran derivative (1) of the present invention may be used in any layer, but it is preferably used in the photoelectric conversion layer.

[0072] The photoelectric conversion layer may contain a fullerene derivative. Examples of the fullerene derivative include

[60] fullerene (C 60 ),

[70] fullerene (C 70 ), phenyl-C 61 -methyl butyrate (

[60] PCBM), phenyl-C 71 -methyl butyrate (

[70] PCBM), phenyl-C 85 -methyl butyrate (

[84] PCBM), etc., and

[60] fullerene (C 60 ) or

[70] fullerene (C 70 ) is preferred.

[0073] When the photoelectric conversion layer contains a fullerene derivative, the mixing ratio of the pyran derivative (1) of the present invention and the fullerene derivative is preferably 1:0.01 or more and 1:100 or less, and more preferably 1:0.1 or more and 1:10 or less.

[0074] The photoelectric conversion element of the present invention may include a hole transport layer between the negative electrode and the photoelectric conversion layer, and an electron transport layer between the positive electrode and the photoelectric conversion layer, for the purpose of improving carrier transportability. The hole transport layer is not particularly limited and has either hole injection or transport, or electron barrier properties, and may be either organic or inorganic. Specifically, examples include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, aminosubstituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers. The electron transport layer is not particularly limited and can have either electron injection or transport, or hole barrier properties. Specifically, examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethanes and anthrone derivatives, or oxadiazole derivatives. Furthermore, to suppress the generation of dark current, an electron blocking layer may be provided between the negative electrode and the photoelectric conversion layer, and a hole blocking layer may be provided between the positive electrode and the photoelectric conversion layer. Examples of electron blocking layers include triarylamines such as 2,7-bis(9-carbazolyl)-9,9-spirobifluorene (Spiro-2CBP) and 3,7-bis[4-(9H-carbazol-9-yl)phenyl]-2,6-diphenylbenzo[1,2-b:4,5-b']difuran (CZBDF). Examples of hole-blocking layers include naphthalenetetracarboxylic acid diimides such as N,N'-di(4-pyridyl)-1,4,5,8-naphthalenetetracarboxylic acid diimide, and tris(8-quinolinolato)aluminum (Alq3). The hole transport layer may also function as an electron-blocking layer, and vice versa.

[0075] There are no particular limitations on the manufacturing method of the photoelectric conversion layer, hole transport layer, electron transport layer, hole blocking layer, and electron blocking layer (hereinafter referred to as "organic layers") of the photoelectric conversion element of the present invention, but film deposition by vacuum deposition is possible. Film deposition by vacuum deposition can be carried out using a general-purpose vacuum deposition apparatus. Considering the manufacturing cycle time and manufacturing cost of organic electroluminescent element fabrication, the vacuum level of the vacuum chamber when forming a film by vacuum deposition is 1 × 10⁻¹⁶, which can be achieved with commonly used diffusion pumps, turbomolecular pumps, cryopumps, etc. -6 Pa or more 1×10 -2 A pressure of Pa or less is preferred. The deposition rate depends on the thickness of the film to be formed, but a rate of 0.005 nm / second to 1.0 nm / second is preferred. Film formation is also possible using general-purpose equipment such as spin coating, inkjet, casting, or dip methods.

[0076] The positive electrode layer and negative electrode layer of the photoelectric conversion element of the present invention are connected to a power source via an electrical conductor such as a wire. Either the positive electrode layer or the negative electrode layer can be in contact with the substrate of the photoelectric conversion element of the present invention. For convenience, the electrode in contact with the substrate is called the lower electrode. In the photoelectric conversion element of the present invention, either the positive electrode layer or the negative electrode layer may be used as the lower electrode.

[0077] In the photoelectric conversion element of the present invention, it is preferable that at least one of the positive electrode layer and negative electrode layer (hereinafter referred to as "electrodes"), which serves as the light-receiving surface, is light-transmitting. As light-transmitting electrodes, general transparent electrode materials can be used, and examples include metal oxides such as indium-tin oxide (ITO), indium-zinc oxide (IZO), tin oxide, aluminum or indium-doped tin oxide, magnesium-indium oxide, or nickel-tungsten oxide, metal nitrides such as gallium nitride, metal selenides such as zinc selenide, or metal sulfides such as zinc sulfide. Metal oxides are preferred in terms of good light transmittance and conductivity, and ITO, IZO, and tin oxide are even more preferred. Furthermore, the electrodes can be modified with plasma-deposited fluorocarbon.

[0078] For the electrode other than the light-receiving surface, in addition to the transparent electrode materials exemplified above, opaque or reflective electrode materials can be used. Examples of such opaque or reflective electrode materials include gold, silver, iridium, molybdenum, palladium, platinum, sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum, aluminum / aluminum oxide (Al2O3) mixture, indium, lithium / aluminum mixture, and rare earth metals.

[0079] There are no particular limitations on the manufacturing method for the electrodes of the photoelectric conversion element of the present invention, but film formation is possible by vacuum deposition, sputtering, electron beam deposition, chemical reaction (sol-gel method, etc.), coating, etc.

[0080] The photoelectric conversion element of the present invention is formed on a substrate. The substrate may be light-transmitting or opaque depending on the intended direction of light reception. Light-transmitting substrates are preferable for receiving light through the substrate, and examples of such substrates include transparent glass, quartz, or plastic. Examples of opaque substrates include silicon and silicon oxide. The substrate may also be a composite structure including multiple material layers.

[0081] The method for manufacturing the photoelectric conversion element of the present invention is not particularly limited, but it can be manufactured by sequentially depositing an electrode layer, an organic layer, and another electrode layer on a substrate. Alternatively, a substrate with an electrode layer already deposited on it may be used, and the organic layer and electrode layer may be deposited sequentially. [Examples]

[0082] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these.

[0083] [ 1 H-NMR measurement] 1 For 1H-NMR measurements, a Bruker ASCEND 400 (400MHz; manufactured by BRUKER) was used.1 ¹H-NMR was performed using deuterated chloroform (CDCl3) as the measurement solvent and tetramethylsilane (TMS) as the internal standard.

[0084] [Thin film fabrication, photoelectric conversion element fabrication, and film thickness measurement] Thin films and photoelectric conversion elements were fabricated using vacuum deposition with an EROLA-500 (ULVAC KIKO, Inc.). The substrates were pre-cleaned with a neutral detergent and pure water, dried, and then cleaned with oxygen plasma. A stylus-type film thickness gauge, DektakXT (BRUKER), was used for film thickness measurement.

[0085] [Absorption Spectrum Measurement] A V-750 spectrophotometer (manufactured by JASCO Corporation) was used for absorption spectrum measurements. Measurements were performed at a scan speed of 400 nm / min. The sample used for measurement was a thin film fabricated on a quartz substrate by vacuum deposition.

[0086] [External quantum efficiency measurement] A solar cell spectroscopic sensitivity analyzer (manufactured by Soma Optical Co., Ltd.) was used to measure the external quantum efficiency. Irradiation light intensity: 50 μW / cm² 2 The measurement was performed using [this method].

[0087] Commercially available reagents were used.

[0088] Synthesis Example 1

[0089] [ka]

[0090] (E)-2-(2-Methyl-6-(4-(thiophen-2-yl)styryl)-4H-pyran-4-ylidene) malononitrile (0.19 g, 0.55 mmol), 2-benzofurancarbaldehyde (0.12 g, 0.83 mmol) and piperidine (0.054 mL, 0.55 mol) were suspended in acetonitrile (50 mL) and stirred at 100 °C for 18 h. The precipitated solid was collected by filtration and washed with acetonitrile, methanol and hexane to obtain 2-(2-((E)-2-(benzofuran-2-yl)vinyl)-6-((E)-4-(thiophen-2-yl)styryl)-4H-pyran-4-ylidene) malononitrile (0.23 g, 89%) as a red solid. 1 1H-NMR (CDCl3): δ 7.67 - 7.61 (m, 3H), 7.61 (d, J = 15.8 Hz, 1H), 7.53 (d, J = 8.2, 0.9 Hz, 1H), 7.47 - 7.32 (m, 7H), 7.28 (ddd, J = 15.8 Hz, 1H), 7.03 (s, 1H), 6.96 (d, J = 15.8 Hz, 1H), 6.74 (d, J = 2.0 Hz, 1H), 6.67 (d, J = 2.0 Hz, 1H), 6.56 (d, J = 15.7 Hz, 1H).

[0091] Synthesis Example - 2

[0092]

Chemical formula

[0093] (E)-2-(2-(4-(dimethylamino)styryl)-6-methyl-4H-pyran-4-ylidene)malononitrile (1.5 g, 4.9 mmol), 2-benzofrancarbaldehyde (1.1 g, 7.4 mmol), and piperidine (0.48 mL, 4.9 mol) were suspended in acetonitrile (100 mL) and stirred at 100 °C for 18 hours. The precipitated solid was filtered and washed with acetonitrile, methanol, and hexane. This solid was suspended in hot acetonitrile, cooled to room temperature, and filtered to obtain a purple solid 2-(2-((E)-2-(benzofuran-2-yl)vinyl)-6-((E)-4-(dimethylamino)styryl)-4H-pyran-4-ylidene)malononitrile (1.6 g, 76%). 1 H-NMR(CDCl3): δ7.61(brd,J=7.8Hz,1H),7.51(dd,J=8.4,0.9Hz,1H),7.48(brd,J=8.7H z,2H),7.46(d,J=15.8Hz,1H),7.39(ddd,J=8.4,7.2,1.3Hz,1H),7.36(d,J=15.8Hz,1H), 7.27(ddd,J=7.8,7.2,0.9Hz,1H),7.00(s,1H),6.93(d,J=15.8Hz,1H),6.72(brd,J=8.7H z,2H),6.69(d,J=2.0Hz,1H),6.59(d,J=2.0Hz,1H),6.53(d,J=15.8Hz,1H),3.08(s,6H).

[0094] Synthesis Example 3

[0095] [ka]

[0096] (E)-2-(2-methyl-6-(4-(piperidine-1-yl)styryl)-4H-pyran-4-ylidene)malononitrile (0.55 g, 1.6 mmol), 2-benzofrancarbaldehyde (0.35 g, 2.4 mmol), and piperidine (0.16 mL, 1.6 mol) were suspended in acetonitrile (100 mL) and stirred at 100 °C for 18 hours. The precipitated solid was filtered and washed with acetonitrile, methanol, and hexane. This solid was dissolved in hot anisole, cooled to room temperature, and filtered to obtain the purple solid 2-(2-((E)-2-(benzofuran-2-yl)vinyl)-6-((E)-4-(piperidine-1-yl)styryl)-4H-pyran-4-ylidene)malononitrile (0.38 g, 50%). 1 H-NMR(CDCl3): δ7.62(brd,J=7.5Hz,1H),7.52(dd,J=8.2,0.9Hz,1H),7.48(brd,J=8.9Hz,2H), 7.46(d,J=15.8Hz,1H),7.39(ddd,J=8.2,7.5,1.3Hz,1H),7.37(d,J=15.7Hz,1H),7.27(ddd,J= 7.5,7.5,0.9Hz,1H),7.00(s,1H),6.95(d,J=15.8Hz,1H),6.92(brd,J=8.9Hz,2H),6.71(d,J=2 .0Hz,1H),6.62(d,J=2.0Hz,1H),6.56(d,J=15.7Hz,1H),3.40-3.30(m,4H),1.76-1.61(m,6H).

[0097] Synthesis Example-4

[0098] [ka]

[0099] (E)-2-(2-methyl-6-(4-morpholinostyryl)-4H-pyran-4-ylidene)malononitrile (0.60 g, 1.7 mmol), 2-benzofrancarbaldehyde (0.38 g, 2.6 mmol), and piperidine (0.17 mL, 1.7 mol) were suspended in acetonitrile (100 mL) and stirred at 100 °C for 18 hours. The precipitated solid was filtered and washed with acetonitrile, methanol, and hexane. This solid was dissolved in hot anisole, cooled to room temperature, and filtered to obtain the red solid 2-(2-((E)-2-(benzofuran-2-yl)vinyl)-6-((E)-4-morpholinostyryl)-4H-pyran-4-ylidene)malononitrile (0.57 g, 69%). 1 H-NMR(CDCl3): δ7.62(brd,J=7.5Hz,1H),7.55-7.50(m,3H),7.47(d,J=15.8Hz,1H),7 .40(ddd,J=7.8,7.5,1.3Hz,1H),7.38(d,J=15.8Hz,1H),7.28(ddd,J=7.8,7.5,0.9Hz, 1H),7.01(s,1H),6.95(d,J=15.8Hz,1H),6.93(brd,J=8.8Hz,2H),6.73(d,J=2.0Hz,1H ),6.65(d,J=2.0Hz,1H),6.61(d,J=15.8Hz,1H),3.91-3.84(m,4H),3.33-3.27(m,4H).

[0100] Evaluation Example 1 A photoelectric conversion element using the pyran derivative of the present invention as a constituent component was fabricated, and its performance was evaluated.

[0101] A glass substrate with transparent ITO electrodes, on which a 2 mm wide ITO film was patterned in stripes, was used as the substrate. This substrate was cleaned with a neutral detergent and pure water, dried, and then cleaned with oxygen plasma. On the cleaned substrate, 3,7-bis[4-(9H-carbazole-9-yl)phenyl]-2,6-diphenylbenzo[1,2-b:4,5-b']difuran (CZBDF, film thickness 30 nm) was used as the hole transport layer, and the pyran derivative (1-18) and

[60] fullerene (C) of the present invention were used as the photoelectric conversion layer. 60A co-evaporated film of ) (thickness 100 nm, co-evaporation ratio 1:1) and an electron transport layer of N,N'-di(4-pyridyl)-1,4,5,8-naphthalenetetracarboxylic acid diimide (thickness 30 nm) were sequentially deposited by vacuum deposition. Subsequently, a metal mask was placed on the substrate perpendicular to the ITO stripe, and aluminum was vacuum deposited as the cathode layer at a deposition rate of 0.3 nm / second. After deposition, this multilayer film was sealed in a nitrogen atmosphere glove box with oxygen and moisture concentrations of 1 ppm or less, and the light-receiving area was 4 mm². 2 A photoelectric conversion element was fabricated. For encapsulation, a glass encapsulation cap and epoxy-type ultraviolet curing resin (manufactured by Nagase ChemteX Corporation) were used.

[0102] Evaluation Comparison Example 1 A photoelectric conversion element was fabricated using the same procedure as in Evaluation Example-1, except that a commercially available 2-tert-butyl-4-(dicyanomethylene)-6-[2-(1,1,7,7-tetramethyljurolidine-9-yl)vinyl]-4H-pyran (DCJTB) was used instead of the pyran derivative (1-18).

[0103] Table 1 shows the measurement results of the external quantum efficiency (when irradiated with light at a wavelength of 450 nm) and dark current of the photoelectric conversion elements fabricated in the evaluation examples and evaluation comparative examples when 3V is applied. Both the external quantum efficiency and dark current are relative values ​​with the measured values ​​of the evaluation comparative example set to 1.00. The photoelectric conversion element of the present invention was driven as a photoelectric conversion element sensitive to the blue light region and showed higher external quantum efficiency and lower dark current compared to evaluation comparative example-1. For a photoelectric conversion element, a higher external quantum efficiency, which is an indicator of sensitivity, is preferable, and a lower dark current, which is an indicator of noise, is preferable. Therefore, it was found that the photoelectric conversion element of the present invention shows superior performance compared to evaluation comparative example-1.

[0104] [Table 1] [Industrial applicability]

[0105] The pyran derivative (1) of the present invention can be used in electronic materials such as organic photodiode materials, organic image sensor materials, organic thin-film solar cell materials, organic semiconductor laser materials, organic EL display materials, and photonic crystal materials.

Claims

1. A pyran derivative represented by formula (1). 【Chemistry 1】 In formula (1), R １ ~R ６ Each of these independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. X １ and X ２ This represents a cyano group. Ar １ This represents a phenyl group or a 2-thiophenyl group, and this phenyl group or 2-thiophenyl group may be substituted with one or more substituents selected from the group consisting of a phenyl group and a dialkylamino group having 2 to 3 carbon atoms. The dialkylamino group may have two alkyl groups bonded together with a nitrogen atom to form a ring. Alternatively, the dialkylamino group may have two alkyl groups bonded together with an oxygen atom to form a ring containing a nitrogen atom. Ar ２ This represents the heteroaromatic group shown in formula (2). 【Chemistry 2】 (In the formula, E represents an oxygen atom. R １ａ ~R ５ａ (where * represents a hydrogen atom, and * represents a bonding site.)

2. In the presence of an acid, equation (3) 【Transformation 3】 (R １ ~R ６ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. X １ and X ２ represent a cyano group. Ar １ represents a phenyl group or a 2-thiophenyl group, and the phenyl group or 2-thiophenyl group may be substituted with one or more substituents selected from the group consisting of a phenyl group and a dialkylamino group having 2 to 3 carbon atoms. The dialkylamino group may form a ring by combining two alkyl groups containing a nitrogen atom integrally. Further, the dialkylamino group may form a ring by combining two alkyl groups through an oxygen atom and containing a nitrogen atom integrally.) and a pyran compound represented by the formula (4) 【Chemistry 4】 [In the formula, Ar ２ Equation (5) 【Transformation 5】 (In the formula, E represents an oxygen atom. R １ａ ~R ５ａ represents a hydrogen atom. * represents a bonding site. ) represents a heteroaromatic group. R ６ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The method is characterized by reacting with a carbonyl compound represented by formula (1) 【Transformation 6】 (In the formula, R １ ~R ６ Ar １ Ar ２ , X １ and X ２ The above has the same meaning as above.) A method for producing pyran derivatives as shown.

3. A photoelectric conversion element comprising the pyran derivative described in claim 1.

4. A photoelectric conversion element comprising the pyran derivative described in claim 1 in a photoelectric conversion layer.

5. The photoelectric conversion element according to claim 4, further comprising a fullerene derivative in the photoelectric conversion layer.

6. Fullerene derivatives are C ６０ or C ７０ The photoelectric conversion element according to claim 5.

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