Organic compound, photo-assisted water electrolysis catalyst, semiconductor thin film electrode, photo-assisted water electrolysis cell, and method for producing hydrogen

Abstract

This organic compound is represented by general formula (1). X includes at least one type of linking group selected from the group consisting of an arylene group and an aromatic heterocyclic group, Y is a single bond or an aliphatic hydrocarbon linking group, Ar is an aromatic heterocyclic group, R1 and R2 are each independently a hydrogen atom or an aliphatic hydrocarbon group, R3, R4, R5 and R6 are each independently a hydrogen atom, an aliphatic hydrocarbon group or an aryl group, and at least one combination selected from the group consisting of R3 and R5, and R4 and R6, may bond to each other to form a ring.

Description

Organic compound, photocatalyst for water electrolysis, semiconductor thin film electrode, photocatalyst for water electrolysis, and method for producing hydrogen

[0001] The present disclosure relates to an organic compound, a photocatalyst for water electrolysis, a semiconductor thin film electrode, a cell for water electrolysis, and a method for producing hydrogen.

[0002] The application of photocatalysts is being considered. In order to improve the electromotive force of photocatalysts, organic dye compounds called sensitizing dyes are sometimes used. Ruthenium dyes are used as sensitizing dyes. However, since ruthenium is a rare metal, organic dye compounds that do not use rare metals are being considered for use as sensitizing dyes.

[0003] Known organic dye compounds that do not use rare metals include carbazole-based organic dyes (Patent Document 1, Non-Patent Document 1, Non-Patent Document 2) and indoline-based organic dyes (Patent Document 2).

[0004] In addition, an organic compound for a sensitizing organic dye has been disclosed that has a large steric hindrance that improves the open-circuit voltage of a cobalt complex redox dye-sensitized solar cell and that can easily expand the π-electron transfer site (Patent Document 3).

[0005] Patent Document 1: International Publication No. 2007 / 119525 Patent Document 2: Japanese Patent Application Laid-Open No. 2005-019252 Patent Document 3: International Publication No. 2015 / 087837

[0006] Non-patent document 1: J. Am. Chem. Soc. , 128, 14256-14257 (2006) Non-patent document 2: J. Mater. Chem. , 19, 4829-4836 (2009)

[0007] When a photocatalyst is applied to water electrolysis to form a photocatalyst, the photocatalyst is evaluated by the solar to hydrogen (STH) conversion efficiency of solar energy to hydrogen energy. Even with conventional photocatalysts using various dyes, no photocatalyst with a practically high STH has been obtained. Therefore, a photocatalyst with a higher STH is desired.

[0008] One aspect of the present disclosure is to provide a novel organic compound that serves as an excellent sensitizing dye. Another aspect of the present disclosure is to provide a photovoltaic water electrolysis catalyst that exhibits good STH. Another aspect of the present disclosure is to provide a semiconductor thin-film electrode that exhibits good STH. Another aspect of the present disclosure is to provide a photovoltaic water electrolysis cell that exhibits good STH. Another aspect of the present disclosure is to provide an efficient method for producing hydrogen.

[0009] Means for solving the above problems include the following aspects: <1> An organic compound represented by the following general formula (1):

[0010]

[0011] [In general formula (1), X contains at least one linking group selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 10 carbon atoms and a substituted or unsubstituted aromatic heterocyclic group having 4 to 8 carbon atoms, and when a plurality of linking groups are contained, the plurality of linking groups are linked to each other via carbon atoms; Y is a single bond or a substituted or unsubstituted aliphatic hydrocarbon linking group having 1 to 4 carbon atoms; Ar is a substituted or unsubstituted aromatic heterocyclic group having 5 to 9 carbon atoms, and the number of carbon atoms constituting the aromatic heterocyclic group is 2 or more; R １ and R ２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms, ３ , R ４ , R ５ and R ６ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms; R ３ and R ５ and R ４ and R ６ may be bonded to each other to form a substituted or unsubstituted ring, and the formed ring may contain a sulfur atom.]

[0012] <2> The organic compound according to <1>, wherein, in general formula (1), Ar is an unsubstituted pyridyl group or a pyridyl group substituted with an alkyl group having 1 to 4 carbon atoms. <3> In general formula (1), R １ ~R ６ The organic compound according to <1> or <2>, which forms a structure represented by the following general formula (2):

[0013]

[0014] [In general formula (2), R １ and R ２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms; Z １ , Z ２ and Z ３ are each independently a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 5 carbon atoms, an oxygen atom, or a sulfur atom; ７ , R ９ , R １０ and R １２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms, ８ and R １１ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, or an unsubstituted alkylsulfanyl group having 1 to 20 carbon atoms.

[0015] <4> In general formula (2), Z １ , Z ２ and Z ３ The organic compound according to <3>, wherein the compound has a structure represented by the following formula (3):

[0016]

[0017] <5> In general formula (2), R ８ and R １１ or an unsubstituted alkylsulfanyl group having 2 to 12 carbon atoms, and the other is a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms.

[0018] <6> The organic compound according to any one of <1> to <5>, wherein, in general formula (1), X includes two or more linking groups selected from the group consisting of the following formulae (4) to (7):

[0019]

[0020] [In formula (7), Z ４ is an oxygen atom or a sulfur atom.

[0021] <7> The organic compound according to any one of <1> to <6>, wherein, in general formula (1), X contains a linking group represented by the following formula (5A) or the following formula (5B):

[0022]

[0023] [In formula (5A) and formula (5B), * represents a bonding site with Y.]

[0024] <8> The organic compound according to any one of <1> to <7>, wherein, in general formula (1), X is a linking group represented by any one of formulas (8) to (10).

[0025]

[0026] [In formulas (8) to (10), * represents a bonding site with Y.]

[0027] <9> The organic compound according to any one of <1> to <8>, wherein in general formula (1), Y is a linking group represented by the following formula (11):

[0028]

[0029] <10> The organic compound according to any one of <1> to <9>, which is a dye. <11> A photocatalyst for water electrolysis, comprising the organic compound according to any one of <1> to <10> and a photocatalyst. <12> A semiconductor thin-film electrode, comprising the organic compound according to any one of <1> to <10> and a compound semiconductor. <13> A cell for water electrolysis, comprising a negative electrode, a positive electrode, and an electrolyte, wherein the negative electrode comprises the semiconductor thin-film electrode according to <12> and a current collector. <14> A method for producing hydrogen, using the semiconductor thin-film electrode according to <12>. <15> A method for producing hydrogen according to <14>, using a solar cell.

[0030] According to one aspect of the present disclosure, a novel organic compound that serves as an excellent sensitizing dye is provided. According to another aspect of the present disclosure, a photovoltaic water electrolysis catalyst that exhibits good STH is provided. According to another aspect of the present disclosure, a semiconductor thin film electrode that exhibits good STH is provided. According to another aspect of the present disclosure, a photovoltaic water electrolysis cell that exhibits good STH is provided. According to another aspect of the present disclosure, an efficient method for producing hydrogen is provided.

[0031] Fig. 1 is an exploded perspective view of a negative electrode; Fig. 2 is a front view of a negative electrode; Fig. 3 is an explanatory diagram illustrating a cell for photovoltaic water electrolysis; Fig. 4 is an explanatory diagram illustrating a cell for photovoltaic water electrolysis; Fig. 5 is an explanatory diagram illustrating a cell for photovoltaic water electrolysis.

[0032] The present disclosure will be described below. However, although the following description of the components may be based on representative embodiments of the present disclosure, the present disclosure is not limited to such embodiments.

[0033] In the present disclosure, combinations of preferred embodiments are more preferred. In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the upper and lower limits. In the numerical ranges described in stages in the present disclosure, the upper or lower limit described in a certain numerical range may be replaced with the upper or lower limit of another staged numerical range. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit described in a certain numerical range may be replaced with a value shown in the examples. In the present disclosure, when multiple substances corresponding to each component are present in the composition, the amount of each component refers to the total amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, "contained primarily" means that the target substance is contained in the largest amount relative to the whole. For example, this indicates that the content of the target substance is 50% by mass or more as a percentage of the whole. In the present disclosure, "mass %" and "wt %" are synonymous, and "parts by mass" and "parts by weight" are synonymous. In the present disclosure, "%" indicating the amount of a component is based on mass unless otherwise specified.

[0034] 1. Organic Compound An organic compound according to one embodiment of the present disclosure (hereinafter also referred to as organic compound) is represented by the following general formula (1).

[0035]

[0036] In general formula (1), X contains at least one linking group selected from the group consisting of substituted or unsubstituted arylene groups having 6 to 10 carbon atoms and substituted or unsubstituted aromatic heterocyclic groups having 4 to 8 carbon atoms, and when multiple linking groups are contained, the multiple linking groups are linked to each other via carbon atoms. Y is a single bond or a substituted or unsubstituted aliphatic hydrocarbon linking group having 1 to 4 carbon atoms. Ar is a substituted or unsubstituted aromatic heterocyclic group having 5 to 9 carbon atoms, and the number of carbon atoms constituting the aromatic heterocyclic group is 2 or more, and R １ and R ２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms, and R ３ , R ４ , R ５ and R ６ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms; R ３ and R ５ and R ４ and R ６ may be bonded to each other to form a substituted or unsubstituted ring, and the bond may contain a sulfur atom.

[0037] The process by which an organic compound according to one embodiment of the present disclosure was obtained will now be described. In photoelectrochemical conversion, it is necessary to capture sunlight, convert it into electric charges, and carry out an efficient chemical reaction. In order to efficiently capture sunlight, plants and photosynthetic systems present in nature efficiently capture sunlight using light-harvesting antennas and carry out photoelectric conversion reactions. Therefore, the present inventors have investigated the use of titanium oxide (hereinafter referred to as "TiO") as a dye that mimics an antenna system. ２In order to efficiently transfer charges to inorganic semiconductors such as ZnO (NbO), and to fix the dye to the inorganic semiconductor, we focused on configuring the entire dye with a part that performs a light-harvesting function (donor), a part that performs an electron transfer function (bridge), and a part that performs an anchor function (anchor).

[0038] Specifically, the donor is represented by the general formula (1) as R １ ~R ６ The bridge is a moiety constituted by X in general formula (1), which has a chromophore capable of efficiently collecting sunlight and is capable of donating electrons to the electron transfer moiety. The bridge is a moiety constituted by X in general formula (1), which is capable of receiving electrons from the moiety functioning as a donor and transferring them to the reaction field. The anchor is a moiety constituted by Ar in general formula (1), which has the function of fixing the dye to an inorganic semiconductor material such as titanium oxide.

[0039] The inventors have discovered that organic compounds comprising donors, bridges, and anchors, each with a specific structure, are excellent sensitizing dyes. The inventors speculate as follows: The unshared electron pair or π orbital on the heteroatom in the anchor aromatic heterocyclic group coordinates with the vacant electron orbital of a metal atom in the inorganic semiconductor (e.g., a titanium atom in titanium oxide), thereby anchoring the compound to the inorganic semiconductor. Because aromatic heterocyclic groups are relatively stable (resistant to hydrolysis) even in environments such as water, the organic compound is stably anchored to the inorganic semiconductor material. The inventors speculate that this allows the organic compound to function as an excellent sensitizing dye. Furthermore, the inventors speculate that, particularly when the organic compound is used in environments such as water, the donor, bridge, and the entire system, including the donor, interact favorably with each other, thereby enabling the compound to function as an excellent sensitizing dye.

[0040] When used as a sensitizing dye in a photocatalyst, an organic compound can improve the STH of the photocatalyst. One embodiment of the present disclosure is a photocatalyst containing an organic compound and a photocatalyst. The concept of "photocatalyst" includes photocatalysts. Examples of photocatalysts include the aforementioned inorganic semiconductors.

[0041] As described above, STH is a value indicating the efficiency of conversion from solar energy to hydrogen energy. Specifically, it is calculated, for example, by the following formula (A):

[0042]

[0043] In formula (A), J is the photocurrent density (mA / cm ２ ), V is the input bias (V), C is the coulomb efficiency (%), and D is the input light energy (mW / cm ２ )

[0044] In the above formula (A), the Coulombic efficiency C is calculated based on the amount of hydrogen produced. When evaluating various organic compounds as sensitizing dyes in photocatalysts, STH (calculated value) calculated assuming that the Coulombic efficiency C is 100% may be used. Using STH (calculated value), various organic compounds can be relatively evaluated as sensitizing dyes in photocatalysts, even if, for example, the amount of hydrogen produced is less than the lower measurement limit of the hydrogen detection device due to a small size of the photoelectrolysis cell and the amount of hydrogen produced cannot be measured.

[0045] Photocurrent density J (mA / cm ２ ) can be an actual measured value. The input bias V (V) is the voltage applied between the electrodes, and can be set to a predetermined voltage by feedback control by the device. The input light energy D (mW / cm ２ ) can be the specification value of the light source, which is a theoretical value.

[0046] The organic compound is well supported on the photocatalyst as a sensitizing dye, and when photoelectrolysis is carried out using the photocatalyst on which the organic compound is supported, a high STH is exhibited.

[0047] In addition, organic compounds have a relatively small HOMO-LUMO gap, which shifts the wavelength of sunlight they absorb to longer wavelengths. As a result, organic compounds can absorb sunlight over a wide wavelength range, such as 600 nm or longer, and can efficiently utilize sunlight components.

[0048] (1-1) X In the above general formula (1), X contains at least one linking group selected from the group consisting of substituted or unsubstituted arylene groups having 6 to 10 carbon atoms and substituted or unsubstituted aromatic heterocyclic groups having 4 to 8 carbon atoms. When X contains multiple linking groups, the multiple linking groups are linked to each other via carbon atoms. As described above, X functions as a bridge in the organic compound. That is, X accepts electrons from the donor portion of the organic compound as a whole and transfers them to the anchor portion supported on the photocatalyst.

[0049] Specific examples of the linking group that is a substituted or unsubstituted arylene group having 6 to 10 carbon atoms include the following.Arylene groups having 6 to 10 carbon atoms, such as a phenylene group or a naphthylene group; monoalkyl-substituted arylene groups having 7 to 10 carbon atoms, such as a methylphenylene group, an ethylphenylene group, a propylphenylene group or a butylphenylene group; dialkyl-substituted arylene groups having 8 to 10 carbon atoms, such as a dimethylphenylene group; trialkyl-substituted arylene groups having 9 or 10 carbon atoms, such as a trimethylphenylene group, a 2,3,5-trimethylphenyl group, a 2,3,6-trimethylphenyl group, a 2,4,5-trimethylphenyl group, a 2,4,6-trimethylphenyl group or a 3,4,5-trimethylphenyl group; monoalkoxyarylene groups having 7 to 10 carbon atoms, substituted with a substituted or unsubstituted alkoxy group having 4 or less carbon atoms, such as a methoxyphenylene group; dialkoxyarylene groups having 8 to 10 carbon atoms, substituted with a substituted or unsubstituted alkoxy group having 4 or less carbon atoms, such as a dimethoxyphenylene group; trialkoxyarylene groups having 9 or 10 carbon atoms substituted with a substituted or unsubstituted alkoxy group having 4 or less carbon atoms, such as a trimethoxyphenylene group; aryl groups having 6 to 10 carbon atoms substituted with a halogen atom, such as a chlorophenylene group, dichlorophenylene group, trichlorophenylene group, bromophenylene group, dibromophenylene group, iodophenylene group, fluorophenylene group, chloronaphthylene group, bromonaphthylene group, difluorophenylene group, trifluorophenylene group, and tetrafluorophenylene group; halogenated alkylaryl groups having 7 to 10 carbon atoms substituted with an alkyl group having 4 or less carbon atoms, some or all of which are substituted with halogen, such as a trifluoromethylphenylene group and a trichloromethylphenylene group; N,N-disubstituted amino-substituted aryl groups having 10 or less carbon atoms such as an N,N-dimethylaminophenylene group, an N,N-diethylaminophenylene group, an N-phenyl-N-methylaminophenylene group, an N-tolyl-N-ethylaminophenylene group, an N-chlorophenyl-N-cyclohexylaminophenylene group, or an N,N-ditolylaminophenyl group; alkylthioarylene groups such as a methylthiophenylene group, an ethylthiophenylene group, a methylthionaphthylene group, or a phenylthiophenylene group, or an arylthioarylene group; and the like.

[0050] Specific examples of the linking group that is a substituted or unsubstituted aromatic heterocyclic group having 4 to 8 carbon atoms include, as the aromatic heterocyclic group, ylene, a thiophene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a benzimidazole ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, an indole ring, a benzimidazole ring, a benzothiazole ring, a benzoxazole ring, a quinoxaline ring, a quinazoline ring, a phthalazine ring, a benzofurazan ring, and a benzothiadiazole ring such as a 2,1,3-benzothiadiazole ring. Specific examples of the substituent in the aromatic heterocyclic group when substituted include a methyl group, an ethyl group, a propyl group, and a butyl group.

[0051] Preferred specific examples of X are linking groups selected from the group consisting of the following formulas (4) to (7). X may be a linking group containing two or more linking groups selected from the group consisting of formulas (4) to (7). The wavy lines in the formulas represent linking positions (the same applies hereinafter).

[0052]

[0053] In general formula (7), Z ４ is an oxygen atom or a sulfur atom.

[0054] X may contain multiple linking groups. The multiple linking groups may be two or more types of linking groups selected from the linking groups exemplified above. When X contains multiple linking groups, the multiple linking groups are linked to each other via carbon atoms.

[0055] When X contains a plurality of linking groups, preferred examples include two or more linking groups selected from the group consisting of the above formulas (4) to (7).

[0056] In general formula (1), X more preferably contains a linking group represented by the following formula (5A) or (5B).

[0057]

[0058] In formula (5A) and formula (5B), * represents a bonding site to Y.

[0059] X is more preferably a linking group of any one of formulas (8) to (10).

[0060] In formulas (8) to (10), * represents a bonding site with Y. When Y is a single bond, * represents a bonding site with a group other than X.

[0061] As described above, X preferably has an oligothiophene or a thiophene incorporating benzothiadiazole as an electron acceptor, more preferably has a thiophene incorporating benzothiadiazole and a phenyl group, and further preferably has a structure of formula (10).

[0062] Since X is configured as described above, it is presumed that the charge transportability and transferability are adjusted in the organic compound as a whole, making it possible to efficiently accept and transfer charges.

[0063] (1-2) Y In the above general formula (1), Y is a single bond or a substituted or unsubstituted aliphatic hydrocarbon linking group having 1 to 4 carbon atoms. Y has the function of suitably linking the donor and the bridge in the organic compound.

[0064] Specific examples of the substituted or unsubstituted aliphatic hydrocarbon linking group having 1 to 4 carbon atoms for Y include linear or branched, saturated aliphatic groups or unsaturated aliphatic groups (i.e., alkenyl groups or alkynyl groups).

[0065] Examples of linear or branched saturated aliphatic groups include methylene, ethylene, propylene, butylene, and isopropylidene. Examples of linear or branched unsaturated aliphatic groups include vinyl, 1-propenyl, allyl (2-propenyl), isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-2-propenyl, 1-methyl-2-propenyl, 2-methyl-1-propenyl, ethynyl, 1-propynyl, 2-propynyl (synonymous with propargyl), 1-butynyl, 2-butynyl, 3-butynyl, and 1-methyl-2-propynyl.

[0066] Y is preferably a single bond or a vinyl group, and more preferably a linking group represented by the following formula (11).

[0067]

[0068] Y is a linking group represented by formula (11), and is preferably an E-type group in which the higher priority substituents are on different sides of the double bond.

[0069] (1-3) Ar In the above general formula (1), Ar is a substituted or unsubstituted aromatic heterocyclic group having 5 to 9 carbon atoms. The aromatic heterocyclic group has two or more carbon atoms. As described above, Ar functions as an anchor in the organic compound. That is, Ar has the function of fixing the organic compound to the inorganic semiconductor material, which is a photocatalyst.

[0070] Specific examples of substituted or unsubstituted aromatic heterocyclic groups having 5 to 9 carbon atoms, wherein the aromatic heterocyclic group contains 2 or more carbon atoms, include a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a benzimidazole ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, an indole ring, a benzimidazole ring, a benzothiazole ring, a benzoxazole ring, a quinoxaline ring, a quinazoline ring, a phthalazine ring, a benzofurazan ring, and a benzothiadiazole ring such as a 2,1,3-benzothiadiazole ring.

[0071] Ar is preferably an unsubstituted pyridyl group or a pyridyl group substituted with an alkyl group having 1 to 4 carbon atoms, more preferably an unsubstituted pyridyl group or a pyridyl group substituted with an alkyl group having 1 to 2 carbon atoms, and even more preferably an unsubstituted pyridyl group.

[0072] (1-4) R １ ~R ６ In the above general formula (1), R １ ~R ６ As described above, the portion constituted by R functions as a donor in the entire organic compound. １ ~R ６The moiety constituted by the formula (I) has a chromophore capable of efficiently capturing sunlight and is a moiety capable of donating electrons to the electron transfer moiety.

[0073] In organic compounds, the three-dimensional structure of the donor moiety is preferably close to planar. Although the mechanism is not clear, it is presumed that an organic compound with a three-dimensional structure of the donor moiety that is close to planar can absorb light of longer wavelengths and thus more light, resulting in an organic compound with a high STH.

[0074] (1-4-1) R １ and R ２ 　 R １ and R ２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms. Specific examples of the substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms include linear alkyl groups having 1 to 3 carbon atoms such as a methyl group, an ethyl group, and an n-propyl group; monoalkyl-substituted alkyl groups having 3 carbon atoms such as an isopropyl group; and cyclic alkyl groups having 3 carbon atoms such as a 1,1,2-trimethylpropyl group and a 1,2,2-trimethylpropyl group.

[0075] R １ and R ２ Preferably, at least one of R １ and R ２ More preferably, they are both hydrogen atoms.

[0076] (1-4-2) R ３ , R ４ , R ５ and R ６ In the above general formula (1), R ３ , R ４ , R ５ and R ６ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. ３ and R ５ and R ４ and R ６may be bonded to each other to form a substituted or unsubstituted ring, and the ring formed may contain a sulfur atom.

[0077] Specific examples of the substituted or unsubstituted aliphatic hydrocarbon group having 1 to 30 carbon atoms include a linear alkyl group having 1 to 30 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-pentadecyl group, an n-icosyl group, an n-pentacosyl group, and an n-triacontyl group; an isopropyl group, an isobutyl group, a sec-butyl group, an isopentyl group, a sec-pentyl group, a 1-methyl group, an ... ethylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1-ethylbutyl group, 2-ethylbutyl group, 1-methylhexyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethylpentyl group, 2-ethylpentyl group, 3-ethylpentyl group, 1-n-propylbutyl group, 1-iso-propylbutyl group, 1-iso-propyl-2-methylpropyl group, 1-methylheptyl group, 2- Methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 6-methylheptyl group, 1-ethylhexyl group, 2-ethylhexyl group, 3-ethylhexyl group, 4-ethylhexyl group, 1-n-propylpentyl group, 2-n-propylpentyl group, 1-iso-propylpentyl group, 2-iso-propylpentyl group, 1-n-butylbutyl group, 1-iso-butylbutyl group, 1-sec-butylbutyl group, 1-tert-butylbutyl group monoalkyl-substituted alkyl groups having 2 to 30 carbon atoms, such as a 2-tert-butylbutyl group, a 2-n-octyl-n-nonyl group, a 2-n-hexyl-n-undecyl group, a 2-ethyl-n-pentadecyl group, a 2-(3'-methyl-n-hexyl)-7-methyl-n-nonyl group, a 1-n-hexyl-n-tridecyl group, a 2-ethyl-n-heptadecyl group, a 2-n-octyl-n-undecyl group, a 1-n-undecyl-n-dodecyl group, and a 1-n-octyl-n-pentadecyl group;tert-butyl group, tert-pentyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethyl-2-methylpropyl group, 1,1-dimethylpentyl group, 1,2-dimethylpentyl group, 1,3-dimethylpentyl group, 1,4-dimethylpentyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,3-dimethylpentyl group, 3,4-dimethylpentyl group, 1 -ethyl-1-methylbutyl group, 1-ethyl-2-methylbutyl group, 1-ethyl-3-methylbutyl group, 2-ethyl-1-methylbutyl group, 2-ethyl-3-methylbutyl group, 1,1-dimethylhexyl group, 1,2-dimethylhexyl group, 1,3-dimethylhexyl group, 1,4-dimethylhexyl group, 1,5-dimethylhexyl group, 2,2-dimethylhexyl group, 2,3-dimethylhexyl group, 2,4-dimethylhexyl group, 2,5-dimethylhexyl group, 3,3-dimethylhexyl group, 3,4-dimethylhexyl group, 3,5-dimethylhexyl group, 4,4-dimethylhexyl group, 4,5-dimethylhexyl group, 1-ethyl-2-methylpentyl group, 1-ethyl-3-methylpentyl group, 1-ethyl-4-methylpentyl group, 2-ethyl-1-methylpentyl group, 2-ethyl-2-methylpentyl group, 2-ethyl-3-methylpentyl group, 2-ethyl-4-methylpentyl group, 3-ethyl-1-methylpentyl group, 3-ethyl-2-methylpentyl group, 3-ethyl- dialkyl-substituted alkyl groups having 3 to 30 carbon atoms, such as a 3-methylpentyl group, a 3-ethyl-4-methylpentyl group, a 1-n-propyl-1-methylbutyl group, a 1-n-propyl-2-methylbutyl group, a 1-n-propyl-3-methylbutyl group, a 1-iso-propyl-1-methylbutyl group, a 1-iso-propyl-2-methylbutyl group, a 1-iso-propyl-3-methylbutyl group, a 1,1-diethylbutyl group, a 1,2-diethylbutyl group, an isoicosyl group, and an isotriacontyl group;1,1,2-trimethylpropyl group, 1,2,2-trimethylpropyl group, 1,1,2-trimethylbutyl group, 1,1,3-trimethylbutyl group, 1,2,3-trimethylbutyl group, 1,2,2-trimethylbutyl group, 1,3,3-trimethylbutyl group, 2,3,3-trimethylbutyl group, 1,1,2-trimethylpentyl group, 1,1,3-trimethylpentyl group, 1,1,4-trimethylpentyl group, 1,2,2-trimethylpentyl group, 1,2,3-trimethyl 1,2,4-trimethylpentyl group, 1,3,4-trimethylpentyl group, 2,2,3-trimethylpentyl group, 2,2,4-trimethylpentyl group, 2,3,4-trimethylpentyl group, 1,3,3-trimethylpentyl group, 2,3,3-trimethylpentyl group, 3,3,4-trimethylpentyl group, 1,4,4-trimethylpentyl group, 2,4,4-trimethylpentyl group, 3,4,4-trimethylpentyl group, 1-ethyl-1,2-dimethylpentyl group trialkyl-substituted alkyl groups having 4 to 30 carbon atoms, such as a 1-ethylbutyl group, a 1-ethyl-1,3-dimethylbutyl group, a 1-ethyl-2,3-dimethylbutyl group, a 2-ethyl-1,1-dimethylbutyl group, a 2-ethyl-1,2-dimethylbutyl group, a 2-ethyl-1,3-dimethylbutyl group, a 2-ethyl-2,3-dimethylbutyl group, a trimethyloctyl group, a trimethyldecanyl group, a trimethylpentadecyl group, a trimethyleicosanyl group, and a trimethylhexacosanyl group; cyclic alkyl groups having 3 to 30 carbon atoms such as cyclopentyl, cyclohexyl, cyclodecane, cyclotetradecane, cyclononadecane, cyclotetracosane, and cycloheptacosane; and alkyl-substituted cyclic alkyl groups having 4 to 30 carbon atoms such as methylcyclopentyl, methylcyclohexyl, 1,2-dimethylcyclohexyl, 1,3-dimethylcyclohexyl, 1,4-dimethylcyclohexyl, and ethylcyclohexyl.

[0078] Specific examples of the substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and specific examples of the linking group that is a substituted or unsubstituted aryl group having 6 to 10 carbon atoms include the following: aryl groups having 6 to 30 carbon atoms, such as a phenyl group, a naphthyl group, an adamantyl group, an anthracene group, a pyrene group, a coronene group, and a perylene group; aryl groups having 7 carbon atoms, such as a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 2-ethylphenyl group, a 4-n-propylphenyl group, a 4-adamantylphenyl group, a 2-adamantylphenyl group, a pentylphenyl group, a 4-isobornylphenyl group, a 3-isobornylphenyl group, and a 2-isobornylphenyl group; monoalkyl-substituted aryl groups of 1 to 30; 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 3,6-dimethylphenyl group, 2,6-di-isopropylphenyl group, 2,3-di-isopropylphenyl group, 2,4-di-isopropylphenyl group, 3,4-di-isopropylphenyl group, 3,6-di-t-butylphenyl group, 2,3 -di-t-butylphenyl group, 2,4-di-t-butylphenyl group, 3,4-di-t-butylphenyl group, 2,6-di-n-butylphenyl group, 2,3-di-n-butylphenyl group, 2,4-di-n-butylphenyl group, 3,4-di-n-butylphenyl group, 2,6-di-i-butylphenyl group, 2,3-di-i-butylphenyl group, 2,4-di-i-butylphenyl group, 3,4-di-i-butylphenyl group, 2,6-di-t-amylphenyl group, 2,3-di-t dialkyl-substituted aryl groups having 8 to 30 carbon atoms, such as a-amylphenyl group, a 2,4-di-t-amylphenyl group, a 3,4-di-t-amylphenyl group, a 2,6-di-i-amylphenyl group, a 2,3-di-i-amylphenyl group, a 2,4-di-i-amylphenyl group, a 3,4-di-i-amylphenyl group, a 2,6-di-n-pentylphenyl group, a 2,3-di-n-pentylphenyl group, a 2,4-di-n-pentylphenyl group, and a 3,4-di-n-pentylphenyl group;trialkyl-substituted aryl groups having 9 or 30 carbon atoms, such as 2,3,4-trimethylphenyl, 2,3,5-trimethylphenyl, 2,3,6-trimethylphenyl, 2,4,5-trimethylphenyl, 2,4,6-trimethylphenyl, and 3,4,5-trimethylphenyl; 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-ethoxyphenyl, propoxyphenyl, butoxyphenyl, 4-cyclopentyloxyphenyl, and 4-cyclohexyloxyphenyl; and substituted or unsubstituted alkoxy groups having 4 or less carbon atoms, such as cyclohexyloxyphenyl, 4-cycloheptenyloxyphenyl, 4-cyclooctanyloxyphenyl, 2-cyclopentyloxyphenyl, 2-cyclohexyloxyphenyl, 2-cycloheptenyloxyphenyl, 2-cyclooctanyloxyphenyl, 3-cyclopentyloxyphenyl, 3-cyclohexyloxyphenyl, 3-cycloheptenyloxyphenyl, and 3-cyclooctanyloxyphenyl. monoalkoxyaryl groups having 7 to 30 carbon atoms, such as 2,3-dimethoxyphenyl group, 2,4-dimethoxyphenyl group, 2,5-dimethoxyphenyl group, 2,6-dimethoxyphenyl group, 3,4-dimethoxyphenyl group, 3,5-dimethoxyphenyl group, 3,6-dimethoxyphenyl group, 1,2-diethoxyphenyl group, 1,4-dihexyloxyphenyl group, 1,2-dioctyloxyphenyl group, and 1,4-didecanyloxyphenyl group; dialkoxyaryl groups having 8 to 30 carbon atoms substituted by a group; trialkoxyaryl groups having 9 to 30 carbon atoms substituted by a substituted or unsubstituted alkoxy group having 4 or less carbon atoms, such as a 2,3,4-trimethoxyphenyl group, a 2,3,5-trimethoxyphenyl group, a 2,3,6-trimethoxyphenyl group, a 2,4,5-trimethoxyphenyl group, a 2,4,6-trimethoxyphenyl group, a 3,4,5-trimethoxyphenyl group, a 1,2,4-triethoxyphenyl group, or a 1,2,4-tributoxyphenyl group;Aryl groups having 6 to 30 carbon atoms substituted with a halogen atom, such as a chlorophenyl group, a dichlorophenyl group, a trichlorophenyl group, a bromophenyl group, a dibromophenyl group, an iodophenyl group, a fluorophenyl group, a chloronaphthyl group, a bromonaphthyl group, a difluorophenyl group, a trifluorophenyl group, a tetrafluorophenyl group, a pentafluorophenyl group, or a hexachlorocyclophenyl group; carbon atoms substituted with an alkyl group having 4 or less carbon atoms, some or all of which are substituted with a halogen atom, such as a trifluoromethylphenyl group or a trichloromethylphenyl group; halogenated alkylaryl groups having 7 to 30 carbon atoms; N,N-disubstituted amino-substituted aryl groups having 10 or less carbon atoms such as N,N-dimethylaminophenyl group, N,N-diethylaminophenyl group, N-phenyl-N-methylaminophenyl group, N-tolyl-N-ethylaminophenyl group, N-chlorophenyl-N-cyclohexylaminophenyl group, and N,N-ditolylaminophenyl group; alkylthioaryl groups such as methylthiophenyl group, ethylthiophenyl group, methylthionaphthyl group, and phenylthiophenyl group, or arylthioaryl groups;

[0079] R ３ and R ５ and R ４ and R ６ may be bonded to each other to form a substituted or unsubstituted ring. ３ and R ５ and bond to each other to form a ring, R ４ and R ６ and R are bonded to each other to form a ring, or ３ and R ５ and are bonded to each other to form a ring, and R ４ and R ６ and R are bonded to each other to form a ring. ３ and R ５ and the ring formed by R ４ and R ６ One or both of the rings formed by and may contain a sulfur atom.

[0080] In general formula (1), R ３ , R ４ , R５ and R ６ It is preferable that the compound forms a structure represented by the following general formula (2).

[0081]

[0082] In the above general formula (2), Z １ , Z ２ and Z ３ are each independently a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 5 carbon atoms, an oxygen atom, or a sulfur atom, and R ７ , R ９ , R １０ and R １２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms, and R ８ and R １１ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, or an unsubstituted alkylsulfanyl group having 1 to 20 carbon atoms.

[0083] R ８ and R １１ One of the groups is preferably a substituted or unsubstituted alkoxy group having 2 to 20 carbon atoms or an unsubstituted alkylsulfanyl group having 2 to 20 carbon atoms, more preferably a substituted or unsubstituted alkoxy group having 2 to 17 carbon atoms or an unsubstituted alkylsulfanyl group having 2 to 17 carbon atoms, even more preferably a substituted or unsubstituted alkoxy group having 2 to 14 carbon atoms or an unsubstituted alkylsulfanyl group having 2 to 14 carbon atoms, particularly preferably a substituted or unsubstituted alkoxy group having 2 to 12 carbon atoms or an unsubstituted alkylsulfanyl group having 2 to 12 carbon atoms, and especially preferably a substituted or unsubstituted alkoxy group having 2 to 12 carbon atoms or an unsubstituted alkylsulfanyl group having 2 to 12 carbon atoms. The other group is preferably a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably a hydrogen atom or an unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms, and even more preferably a hydrogen atom.

[0084] Z １ , Z ２ and Z ３ Among the above, Z is preferably a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, more preferably a substituted or unsubstituted alkoxy group having 5 to 20 carbon atoms, and even more preferably an unsubstituted alkoxy group having 10 to 20 carbon atoms. １ , Z ２ and Z ３ Among the above, a substituted or unsubstituted alkylsulfanyl group having 1 to 20 carbon atoms is preferable, a substituted or unsubstituted alkylsulfanyl group having 5 to 20 carbon atoms is more preferable, and an unsubstituted alkylsulfanyl group having 10 to 20 carbon atoms is even more preferable.

[0085] Specific examples of substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms 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 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group, a dodecyloxy group, a lauryloxy group, a tetradecyloxy group, a myristyloxy group, a pentadecyloxy group, a hexadecyloxy group, a cetyloxy group, a heptadecyloxy group, an octadecyloxy group, a stearyloxy group, a stearyloxy group, a nonadecyloxy group, and an eicosanyloxy group.

[0086] Specific examples of the substituted or unsubstituted alkylsulfanyl group having 1 to 20 carbon atoms include the alkoxy groups listed above in which the oxygen atom is replaced with a sulfur atom.

[0087] In the above general formula (2), Z １ , Z ２ and Z ３ Examples of the alkyl group include linear or branched saturated aliphatic groups or unsaturated aliphatic groups (ie, alkenyl or alkynyl groups) having 1 to 5 carbon atoms.

[0088] Examples of the linear alkylene group or branched saturated aliphatic group include a methylene group, an ethylene group, a propylene group, a butylene group, and an isopropylidene group. Examples of the linear alkylene group or branched unsaturated aliphatic group include a vinyl group, a 1-propenyl group, an allyl group (2-propenyl group), an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a 2-methyl-2-propenyl group, a 1-methyl-2-propenyl group, a 2-methyl-1-propenyl group, an ethynyl group, a 1-propynyl group, a 2-propynyl group (synonymous with a propargyl group), a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, and a 1-methyl-2-propynyl group.

[0089] Among these, a branched saturated aliphatic group having 3 carbon atoms (i.e., an isopropyl group), an oxygen atom, or a sulfur atom is preferred, a branched saturated aliphatic group having 3 carbon atoms is more preferred, and a structure represented by the following formula (3) is even more preferred.

[0090]

[0091] (1-5) Specific Examples of Organic Compounds Specific examples of organic compounds include the organic compounds represented by the following formulas (12) to (35).

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] In formula (31), R ３１ Ha-C ｎ H ２ｎ＋１ Here, n is an integer of 2 to 18, preferably an even number, and more preferably 2, 6, 10, or 14.

[0108]

[0109]

[0110]

[0111]

[0112] 2. Organic Compound as a Dye The organic compound is preferably a dye. When the organic compound is a dye, it can capture the energy of visible light among the wavelengths of light. Furthermore, among dyes, the organic compound as a dye (hereinafter also referred to as a dye) is preferably a sensitizing dye to be supported on a photocatalyst. As described above, the organic compound has moieties that function as a donor, a bridge, and an anchor, each of which has a specific structure. Therefore, the dye is suitably supported on the photocatalyst, and the function of the photocatalyst can be enhanced by light.

[0113] The long wavelength absorption edge of the organic compound is preferably 500 nm or more, more preferably 600 nm or more, and even more preferably 640 nm or more. The long wavelength absorption edge of the organic compound is obtained by measuring the absorbance of the organic compound with a spectrophotometer.

[0114] 3. Semiconductor Thin-Film Electrode One aspect of the present disclosure is a semiconductor thin-film electrode including an organic compound and a compound semiconductor. Here, the organic compound is preferably a dye. Furthermore, the compound semiconductor is preferably a photocatalyst. The semiconductor thin-film electrode according to one aspect preferably includes an organic compound as a dye and a compound semiconductor as a photocatalyst. Here, the organic compound as a dye is preferably supported on the compound semiconductor as a photocatalyst. The semiconductor thin-film electrode according to one aspect may further include a substrate. In this case, the thin film including the organic compound and the compound semiconductor may be provided on only one side of the substrate, or on both sides.

[0115] The compound semiconductor is preferably made of fine particles, more preferably made of nanoparticles.

[0116] Specific examples of compound semiconductors include: TiO ２ , ZnO, In ２ O ３ , SnO ２ , ZrO ２ , Ta ２ O ５ , Nb ２ O ５ , Fe ２ O ３ , Ga ２ O ３ , W.O. ３ , SrTiO ３ Metal oxides and composite oxides such as AgI, AgBr, CuI, and CuBr; metal halides such as ZnS and TiS ２ , ZnO, In ２ S ３ , SnS, SnS ２ , ZrS ２ , Ag ２ S, PbS, CdS, TaS ２ , CuS, Cu ２ S., W.S. ２ , MoS ２ , CuInS ２ Metal sulfides such as CdSe, TiSe ２ , ZrSe ２ , Bi ２ Se ３ , In ２Se ３ , SnSe, SnSe ２ , Ag ２ Se, TaSe ２ , CuSe, Cu ２ Se, WSe ２ , MoSe ２ , CuInSe ２ Metal selenides such as CdTe, TiTe ２ , ZrTe ２ , Bi ２ Te ３ , In ２ Te ３ , SnTe, SnTe ２ , Ag ２ Te, TaTe ２ , CuTe, Cu ２ Te, WTe ２ , MoTe ２ The compound semiconductor is not limited to these specific examples. The compound semiconductor may be TiO ２ , ZnO, and SnO ２ Preferably, the material contains one or more selected from the group consisting of TiO ２ , ZnO, and SnO ２ More preferably, the composition contains one selected from the group consisting of TiO ２ More preferably, it contains TiO ２ It is particularly preferred that:

[0117] For example, commercially available titanium oxide particles such as P25 (manufactured by Nippon Aerosil Co., Ltd.), ST-01 (manufactured by Ishihara Sangyo Kaisha), SP-210 (manufactured by Showa Denko K.K.), DSL-18NRT (manufactured by Dysol Co., Ltd.), Ti-Nanoxide T / SP (manufactured by Solaronix), and PST-18NR (manufactured by JGC Catalysts and Chemicals Co., Ltd.) may be used, or crystalline titanium oxide particles obtained by a sol-gel method from titanium alkoxide through hydrolysis, autoclaving, or the like, as described in J. Am. Ceram. Soc., 80, 3157 (1997), may be used. Titanium oxide particles obtained by a sol-gel method from titanium alkoxide are preferred.

[0118] The average particle size of the compound semiconductor is preferably 5 nm to 1000 nm, and more preferably 10 nm to 300 nm. The compound semiconductor may be a mixture of compounds with different average particle sizes. The compound semiconductor material may be the same, or a mixture of different compounds may be used, or a mixture of compounds with components other than the compound semiconductor may be used.

[0119] As the substrate, a conventionally known substrate can be used, and a substrate having a conductive surface is preferred, a light-transmitting substrate is more preferred, and a transparent conductive substrate such as ITO (indium tin oxide) or FTO (fluorine-doped tin oxide) is even more preferred.

[0120] A conventionally known method can be used to manufacture a semiconductor thin-film electrode, including, but not limited to, a method of forming a thin film containing compound semiconductor nanoparticles on a substrate and immersing the thin film in a solution containing an organic compound that is a dye.

[0121] Specifically, compound semiconductor nanoparticles are thoroughly mixed with water, a polymer such as polyethylene glycol, a surfactant, and the like to form a slurry, which is then applied to a substrate by a method known as the doctor blade method. Alternatively, compound semiconductor nanoparticles may be mixed with a binder polymer and a highly viscous organic solvent, and the resulting mixture may be applied to a substrate by screen printing. The compound semiconductor-coated substrate is baked in air or oxygen at 100°C to 200°C for ITO and 450°C to 600°C for FTO to obtain a compound semiconductor thin-film electrode. The film thickness of the semiconductor thin-film electrode is typically 0.5 μm to 100 μm, and preferably 4 μm to 20 μm.

[0122] Adsorption of the dye onto the surface of the semiconductor thin-film electrode, i.e., support of the dye on the photocatalyst, is carried out by immersing the semiconductor thin-film electrode in a dye solution and leaving it at room temperature for 1 hour or more, or leaving it under heated conditions for 10 minutes to 1 hour, preferably at room temperature for 6 hours or more.

[0123] The solvent used for dye adsorption includes alcoholic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and t-butanol, organic solvents such as chloroform, acetone, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, and mixed solvents thereof. Among these, tetrahydrofuran, ethanol, toluene, and mixed solvents of acetonitrile and toluene are preferred.

[0124] The dye concentration of the dye solution is usually 0.05 mmol / L to 0.5 mmol / L, and preferably 0.2 mmol / L to 0.3 mmol / L.

[0125] 4. Photovoltaic Water Electrolysis Cell A photovoltaic water electrolysis cell according to one embodiment of the present disclosure includes a negative electrode, a positive electrode, a reference electrode, and an electrolyte. The photovoltaic water electrolysis cell may include a case, and the case may contain a negative electrode, a positive electrode, a reference electrode, and an electrolyte. Within the case, an area where the negative electrode and reference electrode are located may be separated from an area where the positive electrode is located by a separator that does not impede the passage of ions. In the photovoltaic water electrolysis cell, the negative electrode and positive electrode are electrically connected. The negative electrode is activated by light and oxidizes a sacrificial agent added to the electrolyte. The positive electrode obtains electrons from the negative electrode to generate hydrogen.

[0126] The negative electrode includes a semiconductor thin-film electrode and a current collector plate for transmitting electrons generated by the semiconductor thin-film electrode to the positive electrode. The semiconductor thin-film electrode and the current collector plate are in at least partial contact with each other.

[0127] The current collector plate is in contact with the semiconductor thin-film electrode and collects electrons generated by the semiconductor thin-film electrode. The current collector plate is made of a metal or the like that can collect electrons. The current collector plate may have an electrode portion including an electrode in the center. Furthermore, the size of the electrode may be reduced from the viewpoint of obtaining a semiconductor thin-film for photochemical water electrolysis with a high STH. The current collector plate may be in contact with at least a portion of the semiconductor thin-film electrode, but it is preferable that the current collector plate be in contact with the semiconductor thin-film electrode over the entire periphery, and it is more preferable that the current collector plate be in close contact with the semiconductor thin-film electrode using a clamping member or the like.

[0128] As an example, as shown in FIG. 1 , a negative electrode 10 according to an embodiment of the present disclosure includes a semiconductor thin-film electrode 11, a current collector 12, an O-ring 13, a first clamping member 14, and a second clamping member 15. The semiconductor thin-film electrode 11 is disposed between the current collector 12 and the first clamping member 14, and a photocatalyst is provided on the surface that contacts the current collector. The current collector 12 is disposed between the semiconductor thin-film electrode 11 and the O-ring 13, and the O-ring 13 is disposed between the second clamping member 15 and the current collector 12. The first clamping member 15 has an electrode portion 16 in its center so that light reaches the semiconductor thin-film electrode 11 from the direction indicated by the arrow. The O-ring is preferably formed of an elastic material such as rubber or silicone. By clamping the O-ring 13, the current collector 12, and the semiconductor thin-film electrode 11 between the first clamping member 14 and the second clamping member 15, a negative electrode 10 can be formed in which the current collector 12 and the semiconductor thin-film electrode 11 are in close contact with each other.

[0129] 2 , in the negative electrode 10, the surface of the semiconductor thin-film electrode 11 on which the photocatalyst is provided is exposed in the electrode portion 16 of the second sandwiching member 15. Therefore, by immersing the negative electrode 10 in the electrolyte solution, the photocatalyst comes into contact with the electrolyte solution and receives light. As a result, water electrolysis by the photocatalyst is performed in the negative electrode 10.

[0130] Any type of positive electrode can be used as long as it can be used as a reduction electrode in an electrolyte. Specifically, a platinum electrode is used. The positive electrode may be made of glass, a polymer film, or the like, on which platinum, carbon, rhodium, ruthenium, or the like is vapor-deposited. Alternatively, the positive electrode may be made of glass, a polymer film, or the like, on which conductive particles are applied. These positive electrodes are preferred because they can function as a catalyst for the reduction reaction.

[0131] The electrolyte solution may contain at least an electrolyte and water, and generate hydrogen at the positive electrode through water electrolysis. Conventional electrolyte solutions used in water electrolysis may be used, including triethanolamine, EDTA (ethylenediaminetetraacetic acid), EDTA-Na (ethylenediaminetetraacetic acid disodium salt), methanol, ethanol, isopropanol, ethylene glycol, glycerol, glucose, lactic acid, formic acid, acetic acid, sodium sulfate, sodium sulfite, and mixtures thereof. A pH of 0 to 14 may be used. Among these, an aqueous ascorbic acid solution with a pH of 2 to 6 is preferably used. The pH is measured at 25±5°C. The pH is measured using a pH meter.

[0132] As shown in FIGS. 3 to 5 , a photovoltaic water electrolysis cell 20 according to one embodiment of the present disclosure contains a negative electrode 10, a reduction electrode 21 facing the negative electrode 10, and an electrolyte 22. The photovoltaic water electrolysis cell 20 includes a light-transmitting container 23 that allows light irradiated onto the cell 20 from a light source external to the cell 20 to pass through to the negative electrode 10. The negative electrode 10 and the reduction electrode 21 are inserted into the light-transmitting container 23 so that they face each other and are spaced apart, respectively, as the negative electrode and the positive electrode. The negative electrode 10 and the reduction electrode 21 are electrically connected via an external circuit 24, allowing the negative electrode 10 to receive light from the light source. The light source is not limited, and may include sunlight, artificial light sources such as xenon lamps, and LEDs. As shown in FIG. 4 , the electrode portion 16 is not limited to a circular shape and may have another shape, such as a rectangular shape. Furthermore, as shown in FIG. 5 , the area of ​​the electrode portion 16 may be adjusted to a smaller shape.

[0133] The external circuit 24 may be connected to an auxiliary power source, and the auxiliary power source is preferably, for example, a solar cell. With the above configuration, hydrogen is generated near the reduction electrode 21 when the anode 10 is irradiated with light.

[0134] 5. Hydrogen Production Method A hydrogen production method according to one aspect of the present disclosure uses a semiconductor thin-film electrode. The semiconductor thin-film electrode has a photocatalyst supporting an organic compound, and therefore has a high STO when hydrogen is produced by water electrolysis.

[0135] In addition, in the hydrogen production method according to one aspect of the present disclosure, a solar cell may be used as the auxiliary power source.

[0136] The present disclosure will be described in more detail below based on examples, but the present disclosure is not limited to these examples. The materials, amounts used, ratios, and treatment procedures shown in the following examples can be changed as appropriate as long as they do not deviate from the spirit of the present disclosure. Regarding the organic compounds shown in each formula, for example, the organic compound shown in formula (12) is also referred to as compound (12). The pH was measured at 25°C using LAQUAact (registered trademark) D-71 (manufactured by HORIBA, Ltd.).

[0137] [1] Measurement and Evaluation Methods Various physical properties were measured and evaluated by the following methods.

[0138] [1.1] Measurement of Organic Compounds For organic compounds, the HOMO (eV), LUMO (eV), HOMO-LUMO gap (eV) (hereinafter also referred to as gap; in Tables 1 to 5, it is referred to as "gap"), and long wavelength absorption edge were measured. The HOMO was calculated by electrochemically measuring the oxidation level of the molecule in solution. Specifically, a glassy carbon working electrode, a platinum counter electrode, and an Ag / AgNO ３ Using a CV cell equipped with a reference electrode, an organic compound was dissolved at a concentration of 1 mM in a cell containing 1 ml of 0.1 M tetrabutylammonium hexafluorophosphate-tetrahydrofuran (type) as a solvent, and measurements were carried out at a sweep rate of 50 mV / s.

[0139] The gap was calculated from a Tauc plot (the following formula (B)) prepared with reference to J. Tauc, R. Grigorovici, and A. Vancu, Phys. Status Solidi, 15 627 (1966).

[0140] (hνα) １／ｎ =k(hν-Eg) (B)

[0141] where h is Planck's constant, v is frequency, α is absorption coefficient, k is proportionality constant, and Eg is band gap. The unit of hv is eV (electron volt), and n is direct allowed transition (n=1 / 2).

[0142] Spectral horizontal axis hν, vertical axis (hνA) ２ A curve plotted on the graph was drawn to obtain the Tauc plot. Here, in the Tauc plot, the value at the point where the tangent to the inflection point of the plot curve intersects with the horizontal axis (hν axis) was taken as the band gap (Eg) value. In addition, λ calculated from the above hν value using hν = 1239.7 / λ was taken as the absorption wavelength edge. The LUMO was taken as the value obtained by subtracting the gap from the HOMO calculated as described above.

[0143] In addition, for various compounds, the mass of the molecular ion in mass spectrometry is [M] ＋ or [M+H] ＋ For compounds, the mass determined by matrix-assisted laser desorption / ionization time-of-flight mass spectrometry is indicated as MS (MALDI-TOF).

[0144] [1.2] Measurement of STH Three types of electrochemical flow cells, which are photochemical water electrolysis cells with different cell areas, were used. Specifically, the area supporting each organic compound was a square of 5.08 cm ２ The first cell (see FIG. 4) has a diameter of 0.5 cm and the area of ​​each organic compound is circular. ２ The second cell (see FIG. 3) has a square area of ​​0.64 cm , which supports each organic compound. ２ The first cell was used in Examples 1 to 12 and Comparative Examples 1 to 5, which will be described below. The second cell was used in Examples 13 and 14. The third cell was used in Examples 15 to 19. The STH was measured using the first cell, second cell, and third cell as follows.

[0145] FTO glass (manufactured by Aldrich, 8Ω) was ultrasonically cleaned with acetone at 10 sccm ２The titanium dioxide (anatase) film was pretreated with ozone plasma treatment (FemtoScience) at 100 W for 10 minutes. Titanium dioxide paste (Solanonix, TiNanoxide T / SP) was screen-printed and baked at 500°C for 1 hour. The thickness of the baked titanium dioxide film was 10 μm. The titanium dioxide film obtained by the above method was then coated with 1 × 10 －４ The titanium dioxide film was immersed in a THF solution of each of the organic compounds of M for 24 hours to support each of the organic compounds on the surface of the titanium dioxide film.

[0146] Using each organic compound, the negative electrode 10 shown in FIG. 1 was fabricated. Using this negative electrode 10, a photochemical water electrolysis cell (electrochemical flow cell) was fabricated as follows (see FIGS. 3 to 5), and the STH was measured. The electrochemical flow cell VB11A (EC frontier Japan, Arflow, 10 sccm) equipped with an ECstat-302 was used, and all aqueous solutions were adjusted to pH 4 (25°C) with hydrochloric acid or sodium hydroxide before use. The electrolyte was a 0.1 M Na ２ SO ４ Hydrogen was detected using a gas chromatograph GC3210 (GL Sciences, TCD, molecular sieve 5A, Ar carrier). All light sources were fitted with a long-pass filter (100 mW / cm) of 400 nm or more. ２ A solar simulator (HAL-320W, ASAHI Spectra, Japan) equipped with a 1000 Watt-hour power supply was used.

[0147] Light irradiation was performed using the electrochemical flow cell described above, and the photocurrent density (Jsc) [A / cm ２ ] was measured. When the first cell was used, the amount of hydrogen produced could be measured, so the STH was calculated using the above formula (A) based on the amount of hydrogen produced, and the STH (calculated value) was calculated using the above formula (A) assuming the Coulomb efficiency to be 100%. These STH values ​​are shown in Tables 1, 2, and 3. When the second cell and the third cell were used, the amount of hydrogen produced could not be measured, so the STH (calculated value) was calculated using the above formula (A) assuming the Coulomb efficiency to be 100%, and is shown in Tables 4 and 5.

[0148] Specifically, the STH was calculated as follows: For example, in Example 1, the photocurrent density (Jsc) was 3.15 mA / cm ２ A current of 2.5% was calculated by comparing this with the amount of hydrogen produced measured with a TCD gas chromatograph (Shimadzu Corporation, GC-8A) to determine the Coulomb efficiency and calculating the STH. When the Coulomb efficiency was set to 100%, the calculated STH was 2.5%.

[0149] The STH was evaluated, and those with an STH of 8.5 or more were rated as the best (indicated as AAA in the table), those with an STH of less than 8.5 and an STH of 4.5 or more were rated as good (indicated as AA in the table), those with an STH of less than 4.5 and an STH of 1.5 or more were rated as acceptable (indicated as A in the table), and those with an STH of less than 1.5 were rated as unacceptable (indicated as B in the table).

[0150] [2] Synthesis of Organic Compound [Example 1] Organic compound (12) represented by formula (12) was synthesized as follows. 9H-carbazole (2.51 g), 1-(hexadecyloxy)-4-iodobenzene (8.00 g), L-proline (550 mg), K ２ CO ３ A mixture of (6.21 g) and CuI (450 mg) was dried. Then, dry DMSO (dimethyl sulfoxide, 60 ml) was added to the mixture, and N ２ The mixture was heated at 120° C. under an atmosphere for 48 hours. The reaction mixture was quenched with water and then added with CH ２ Cl ２ Extracted with anhydrous MgSO ４ The solid was purified by silica gel chromatography to obtain compound (12-1) as a pale yellow solid (2.18 g, 30% yield). The composition and mass of compound (12-1) were as follows: ３５ H ４６ NO [M+H] ＋ Exact Mass=484.4 MS(MALDI-TOF)=484.4

[0151] Dry DMF (N,N-dimethylformamide, 10 ml) and POCl ３ (2.98 ml) of the mixture ２The mixture was stirred at 0°C under atmospheric pressure. After 1 hour, a solution of compound (12-1) (1.49 g) in 1,2-dichloroethane (30 ml) was added to the mixture, and the mixture was heated at 80°C until compound (12-1) disappeared. Then, ice water was poured into the reaction mixture, and ２ Cl ２ The organic layer was washed with water and extracted with anhydrous MgSO ４ The solid was dried at 40°C. The solid was purified by silica gel chromatography to obtain compound (12-2) as a pale yellow solid (807 mg, 51% yield). The composition and mass of compound (12-2) were as follows: ３５ H ４６ NO ２ [M+H] ＋ Exact Mass=512.8 MS(MALDI-TOF)=512.3

[0152] Compound (12-2) (449 mg) was added to a mixed solvent of MeOH (13 ml) and dry THF (tetrahydrofuran, 13 ml), and then N ２ NaBH ４ (224 mg) was added. After 2 h, the reaction mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous Na ２ SO ４ The solvent was removed and the resulting crude product (440 mg) was used in the next step without further purification. ３ A mixture of HBr (triphenylphosphine hydrobromide, 295 mg) and dry toluene (15 ml) was ２ The mixture was refluxed under atmospheric pressure for 2 hours. After that, the solvent was removed from the mixture, and the mixture was washed with cooled toluene to obtain compound (12-3) as a pale yellow powder (716 mg, 97% yield in two steps). The composition and mass of compound (12-3) were as follows: C ５３ H ６２ BrNOP[M+H] ＋ Exact Mass=840.0 MS(MALDI-TOF)=839.9

[0153] A solution of compound (12-3) (537 mg) in dry DMF (30 ml) was２ [2,2':5',2''-terthiophene]-5,5''-dicarboxaldehyde (426 mg), 18-crown-6 (28 mg), K ２ CO ３ (550 mg) and dry DMF (20 ml). After the addition, the reaction mixture was stirred at 70° C. for 3 hours. The reaction mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous MgSO ４ The mixture was dried at 40°C. Purification by silica gel chromatography gave compound (12-4) as an orange solid (502 mg, 60% yield). The composition and mass of compound (12-4) were as follows: ４９ H ５４ NO ２ S ３ [M+H] ＋ Exact Mass=785.2 MS(MALDI-TOF)=785.2

[0154] Compound (12-4) (100 mg), 2-(pyridin-4-yl)acetonitrile (137 mg), piperidine (0.1 ml), and CHCl ３ (30 ml) of the mixture was added to N ２ The mixture was heated at 70° C. under atmospheric pressure overnight. After cooling, the reaction mixture was quenched with water and extracted with THF. The organic layer was washed with saturated brine and anhydrous Na ２ SO ４ The silica gel was purified by chromatography to give the organic compound (12) as a dark red solid (72 mg, 63% yield).

[0155] Organic compound (12) １ H NMR (CDCl ３The analytical results by a frequency (Hz) of 600 MHz were as follows: δ 0.88 (t, J = 3.1 Hz, 3H), 1.21-1.37 (m, 22H), 1.37-1.43 (m, 2H), 1.48-1.53 ​​(m, 2H), 1.83-1.89 (m, 2H), 4.06 (t, J = 3.2 Hz, 2H), 7.00 (d, J = 1.8 Hz, 1H), 7.09-7.17 (m, 5H), 7.21-7.25 (m, 2H), 7.28-7.33 (m, 5H), 7.35-7.44 (m, 3H), 7.52 (d, J = 2.8Hz, 1H), 7.56 (d, J = 4.4Hz, 1H), 7. 59 (d, J = 2.0Hz, 1H), 7.79 (s, 1H), 8.16 (d, J = 6.9Hz, 1H), 8.22 (s, 1H), 8.67 (d, J = 2.8Hz, 2H)

[0156] The measurement results and evaluation results of the organic compound (12) are shown in Table 1.

[0157]

[0158]

[0159]

[0160]

[0161]

[0162] Example 2 Organic compound (13) represented by formula (13) was synthesized as follows: 4,4-diphenyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene (prepared with reference to Polymer, 2014, 55, 6641-6872) (589 mg) and CHCl ３ (100 ml) of the mixture ２ The mixture was cooled to −30° C. under atmospheric pressure. NIS (N-iodosuccinimide, 803 mg) was added over 1 hour at −30° C., and the mixture was allowed to react overnight at room temperature. After the reaction, the mixture was purified by silica gel chromatography to obtain compound (13-1) as a dark red solid (540 mg, 52% yield). ２１ H １２ I ２ S ２[M+] Exact Mass=582.3 MS(MALDI-TOF)=582.3

[0163] Compound (13-1) (387 mg), (5-formylthiophen-2-yl)boronic acid 42 (406 mg), K ２ CO ３ (800mg), Pd(dppf)Cl ２ -CH ２ Cl ２ (60 mg) and dry DMF (18 ml) was added to ２ The mixture was heated at 80°C under atmospheric pressure for 24 hours. After removing the solvent, the mixture was purified by silica gel chromatography to obtain compound (13-2) as a dark red solid (340 mg, 95% yield). ３１ H １８ O ２ S ４ [M+] Exact Mass=551.7 MS(MALDI-TOF)=551.4

[0164] A mixture of compound (14-3) (see Example 3, 261 mg) and dry DMF (30 ml) was added to compound (13-2) (248 mg), 18-crown-6-ether (30 mg), K ２ CO ３ (1.0 g) and dry DMF (30 ml) ２ The mixture was added dropwise under atmospheric pressure at 80° C. over 3 hours. The reaction mixture was stirred at 80° C. for 3 hours. The reaction mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous MgSO ４ The mixture was dried at 4°C for 1 hour. Purification by silica gel chromatography gave compound (13-3) as an orange solid (247 mg, 77% yield). ６６ H ６４ NO ２ S ５ [M+H] ＋ Exact Mass=1063.5 MS(MALDI-TOF)=1063.2

[0165] Compound (13-3) (121 mg), 2-(pyridin-4-yl)acetonitrile (130 mg), piperidine (0.1 ml), and CHCl ３ (30 ml) of the mixture was added to N ２ Heated under atmosphere overnight at 70° C. Evaporation of the solvent and purification by silica gel chromatography gave organic compound (13) as a dark red solid (80 mg, 63% yield).

[0166] Organic compound (13) １ H NMR (CDCl ３ The analytical results by a frequency (Hz) of 600 MHz were as follows: δ 0.88 (t, J = 3.0 Hz, 3H), 1.18-1.43 (m, 24H), 1.46-1.54 (m, 2H), 1.79-1.87 (m, 2H), 4.03 (d, J = 3.1 Hz, 2H), 6.14 (dd, J = 4.1, 14.5 Hz, 2H), 6.65 (d, J = 8.0 Hz , 1H), 6.75-6.88 (m, 4H), 6.91-7.00 (m, 2H), 7.04 (s, 1H), 7.06-7.13 (m, 3H), 7.17 (s, 1H), 7.20-7.34 (m, 15H), 7.51 (brs, 2H), 7.77 (s, 1H), 8.65 (brs, 2H)

[0167] The measurement results and evaluation results of the organic compound (13) are shown in Table 1.

[0168]

[0169]

[0170]

[0171]

[0172] [Example 3] Organic compound (14) represented by formula (14) was synthesized as follows: Phenothiazine (2.49 g), 1-(hexadecyloxy)-4-iodobenzene (8.29 g), Cu (640 mg), K ２ CO ３ A mixture of 18-crown-6-ether (500 mg) and 1,2-dichlorobenzene (40 ml) was added to the mixture, and N ２The mixture was refluxed under atmospheric pressure for 48 hours. The mixture was dried and purified by silica gel chromatography to give compound (14-1) as a pale yellow solid (5.50 g, 85% yield). ３４ H ４６ NOS [M+H] ＋ Exact Mass=516.3 MS(MALDI-TOF)=516.9

[0173] Dry DMF (20 ml) and POCl ３ (6 ml) of the mixture ２ The mixture was stirred at 0°C under atmospheric pressure. After 1 hour, compound (14-1) (5.3 g) in 1,2-dichloroethane (60 ml) was added to the mixture, and the mixture was heated at 40°C until compound (14-1) disappeared. After compound (14-1) disappeared, ice water was poured into the reaction mixture, and CH ２ Cl ２ The organic layer was washed with water and extracted with anhydrous MgSO ４ The mixture was dried at 40°C. Purification by silica gel chromatography gave compound (14-2) as a pale yellow solid (4.48 g, 80% yield). ３５ H ４６ NO ２ S[M+H] ＋ Exact Mass=544.8 MS(MALDI-TOF)=544.9

[0174] A mixture of compound (14-2) (944 mg), MeOH (30 ml), and dry THF (30 ml) was added with N ２ NaBH ４ (264 mg) was added. After 2 h, the mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous Na ２ SO ４ The solvent was removed to give a crude product, which was used in the next step without further purification. ３ A mixture of HBr (597 mg) and dry toluene (30 ml) was ２The mixture was refluxed under atmospheric pressure for 2 hours. After drying, the mixture was washed with cold diethyl ether to give compound (14-3) as a pale yellow powder (1.16 g, 87% yield for two steps). ５３ H ６１ BrNOPS[M] ＋ Exact Mass=871.0 MS(MALDI-TOF)=871.2

[0175] A solution of compound (14-3) (300 mg) in dry DMF (30 ml) was ２ The mixture was added dropwise to a mixture of [2,2':5',2''-terthiophene]-5,5''-dicarboxaldehyde (155 mg), 18-crown-6 (28 mg), KCO (550 mg), and dry DMF (20 ml) under atmospheric pressure at 80°C over 3 hours. The reaction mixture was stirred at 80°C for an additional 3 hours. The reaction mixture was quenched with water and diluted with CH ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous MgSO ４ The mixture was dried at rt. Purification by silica gel chromatography gave compound (14-4) as an orange solid (160 mg, 58% yield). ４９ H ５４ NO ２ S ４ [M+H] ＋ Exact Mass=817.2 MS(MALDI-TOF)=817.2

[0176] Compound (14-4) (100 mg), 2-(pyridin-4-yl)acetonitrile (144 mg), piperidine (0.1 ml), and CHCl ３ (30 ml) of the mixture was added to N ２ The mixture was heated at 70° C. under atmospheric pressure overnight. After cooling, the reaction mixture was quenched with water and extracted with THF. The organic layer was washed with saturated brine and anhydrous Na ２ SO ４ Drying at rt Purification by silica gel chromatography gave organic compound (14) as a dark red solid (82 mg, 73% yield).

[0177] Organic compound (14) １ H NMR (CDCl ３, 400 MHz), the analytical results were as follows: δ 0.88 (t, J = 4.1 Hz, 3H), 1.47-1.54 (m, 26H), 1.81-1.89 (m, 2H), 4.03 (t, J = 3.9 Hz, 2H), 6.15 (dd, J = 5.4, 16.5 Hz, 2H), 6.66-7.02 (m, H), 7.06-7.17 (m, 5H), 7.21 (s, 1H), 7.23-7.34 (m, 3H), 7.52 (brs, 2H), 7.57 (s, 1H), 7.78 (s, 1H), 8.66 (brs, 2H).

[0178] The measurement results and evaluation results of the organic compound (14) are shown in Table 1.

[0179]

[0180]

[0181]

[0182]

[0183]

[0184] [Example 4] Organic compound (15) represented by formula (15) was synthesized as follows. Compound (15-1) (250 mg), compound (15-2) (prepared with reference to Organic Letters, 2009, 11(1), 1-4.) (198 mg), K ２ CO ３ (101mg), Pd(PPh ３ ) ４ (35 mg), toluene (30 mL), and H ２ A mixture of N ２ The reaction was carried out at 100°C for 48 hours under atmospheric pressure. After the reaction, the organic layer was washed with saturated saline and anhydrous MgSO ４ The mixture was dried at 4°C for 1 hour. Purification by silica gel chromatography gave compound (15-3) as an orange solid (188 mg, 51% yield). ３８ H ３１ N ３ OS ２ [M] ＋ Exact Mass=609.3 MS(MALDI-TOF)=609.3

[0185] Compound (15-3) (188 mg), 2-(pyridin-4-yl)acetonitrile (367 mg), piperidine (0.2 mL), and CHCl ３ (40 mL) of N ２ Heated under atmosphere overnight at 70° C. Evaporation of the solvent and purification by silica gel chromatography gave organic compound (15) as a red solid (122 mg, 55% yield).

[0186] Organic compound (15) １ H NMR (CDCl ３ The analytical results by NMR (δ = 600 MHz) were as follows: δ 1.66 (s, 6H), 1.71 (s, 12H), 7.14-7.20 (m, 2H), 7.39-7.48 (m, 5H), 7.71 (s, 4H), 8.06 (d, J = 7.8 Hz, 1H), 8.31 (s, 1H), 8.74-8.78 (m, 3H), 8.81 (d, J = 7.6 Hz, 1H).

[0187] The measurement results and evaluation results of the organic compound (15) are shown in Table 1.

[0188]

[0189]

[0190]

[0191]

[0192] [Example 5] Organic compound (16) represented by formula (16) was synthesized as follows: Dry DMF (10 ml) and POCl ３ (6 ml) of the mixture ２ The mixture was stirred at room temperature under atmospheric pressure. After 1 hour, a solution of compound (16-1) (prepared with reference to Organic Letters, 2009, 11(1), 1-4) (1.0 g) in 1,2-dichloroethane (30 ml) was added to the mixture, and the mixture was heated at 40°C until compound (16-1) disappeared. After compound (16-1) disappeared, ice water was poured into the reaction mixture, and CH ２ Cl ２ The organic layer was washed with water and extracted with anhydrous MgSO ４The mixture was dried at 4°C for 1 hour. The mixture was purified by silica gel chromatography to give compound (16-2) as a pale yellow solid (775 mg, 72% yield). ２８ H ２８ NO [M+H] ＋ Exact Mass=393.5 MS(MALDI-TOF)=393.6

[0193] Compound (16-2) (1.27 g), MeOH (20 ml), and dry CH ２ Cl ２ (20 ml) of N ２ NaBH ４ (600 mg) was added. After 2 h, the mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous Na ２ SO ４ The solvent was removed to give the crude product (1.27 g), which was used in the next step without purification. ３ A mixture of HBr (1.11 mg) and dry toluene (30 ml) was ２ The mixture was refluxed under atmospheric pressure for 2 hours. After drying, the mixture was washed with cooled toluene to give compound (16-3) as a pale yellow powder (2.20 g, 95% yield for two steps). ４６ H ４４ BrNP[M] ＋ Exact Mass=720.2 MS(MALDI-TOF)=720.2

[0194] A solution of compound (16-3) (200 mg) in DMF (30 ml) was ２ [2,2':5',2''-terthiophene]-5,5''-dicarboxaldehyde (118 mg), 18-crown-6 (14 mg), K ２ CO ３ (275 mg) and dry DMF (20 ml). The reaction mixture was stirred at 80° C. for an additional 3 hours. The reaction mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous MgSO４ The mixture was dried at rt. Purification by silica gel chromatography gave compound (16-4) as an orange-red solid (120 mg, 64% yield). ４２ H ３６ NOS ３ [M+H] ＋ Exact Mass=666.2 MS(MALDI-TOF)=666.2

[0195] Compound (16-4) (100 mg), 2-(pyridin-4-yl)acetonitrile (177 mg), piperidine (0.1 ml), and CHCl ３ (30 ml) of the mixture was added to N ２ The mixture was heated at 80° C. under atmospheric pressure overnight. After cooling, the reaction mixture was quenched with water and extracted with THF. The organic layer was washed with saturated brine and anhydrous Na ２ SO ４ Drying at rt Purification by silica gel chromatography gave organic compound (16) as a dark red solid (65 mg, 57% yield).

[0196] Organic compound (16) １ H NMR (CDCl ３ , 600 MHz) gave the following results: δ 1.66 (s, 6H), 1.67 (s, 12H), 6.92-7.02 (m, 2H), 7.10-7.18 (m, 5H), 7.26 (dd, J=1.2, 21.9 Hz, 2H), 7.36-7.43 (m, 4H), 7.45-7.62 (m, 5H), 7.80 (s, 1H), 8.67 (brs, 2H).

[0197] The measurement results and evaluation results of the organic compound (16) are shown in Table 1.

[0198]

[0199]

[0200]

[0201]

[0202]

[0203] [Example 6] Organic compound (17) represented by formula (17) was synthesized as follows. Thiophene-2-carbaldehyde (1.35 g), ethylene glycol (2.68 ml), and p-toluenesulfonic acid (0.01 g) were dissolved in toluene (60 ml) and reacted under reflux. After cooling to room temperature, the mixture was washed with a 10% NaOH solution and then filtered. ２ Cl ２ The organic layer was extracted with anhydrous Na ２ SO ４ After drying at 400°C, filtration and evaporation of the solvent gave the aldehyde-protected product as a brown oil (1.64 g, 88% yield). To a solution of the product (0.9 g) in dry THF (30 ml) was then added n-butyllithium (1.6 M in hexane, 7.25 ml) at -78°C. After 1 hour at 78°C, tributyltin chloride (2.81 ml) was added dropwise to the above reaction mixture. After stirring at room temperature for 24 hours, the mixture was quenched with 20 ml of saturated aqueous ammonium chloride solution and extracted with hexane. The organic layer was washed with anhydrous NaCl and extracted with hexane. ２ SO ４ The resulting compound (17-1) was used in the next reaction without further purification (1.08 g).

[0204] Compound (17-1) １ H NMR (CDCl ３ The analytical results by NMR (1H, d, J = 3.24 Hz), 7.07 (1H, d, J = 3.3 Hz), 6.18 (1H, s), 4.18 (2H, m), 4.05 (2H, m), 1.56 (6H, m), 1.32 (6H, m), 1.09 (6H, m), 0.91 (9H, m).

[0205] 4-Formylphenylboronic acid, 4,7-dibromobenzo[c][1,2,5]thiazole, K ２ CO ３ , Pd(PPh ３ ) ４ (0.05 mol%), benzene, and ethanol mixture ２ The reaction was carried out at 80° C. for 4 hours under atmospheric pressure. After the reaction, the organic layer was washed with 2M Na ２ CO ３ Wash with anhydrous MgSO４ The extract was dried at rt and purified by silica gel chromatography to obtain compound (17-2).

[0206] Compound (17-2) １ H NMR (CDCl ３ , 600 MHz), the analytical results were as follows: δ 7.67 (1H, Ar-H, d, J = 7.5 Hz), 7.98 (1H, Ar-H, d, J = 7.56 Hz), 8.05 (2H, Ar-H, d, J = 8.46 Hz), 8.09 (2H, Ar-H, d, J = 8.34 Hz), 10.12 (s, 1H, CHO).

[0207] Compound (17-1) and compound (17-2) were dissolved in dry THF (10 ml) in a Schlenk flask under an Ar atmosphere, and the solution was degassed for 20 minutes. ３ ) ２ Cl ２ (10.0 mg) was added, and the solution was degassed again for 10 minutes. Then, the mixture was stirred at 75° C. for 5 hours. The reaction mixture was poured into water (20 ml) and ２ Cl ２ The combined organic layer was washed with water (20 ml) and extracted with Na ２ SO ４ The solvent was removed by drying on a lid, and the crude product was purified by column chromatography to obtain compound (17-3).

[0208] To a solution of compound (17-3) (53 mg) in dry DMF (10 ml) was added 18-crown-6-ether (12 mg) and K ２ CO ３ (30 mg) was added. The mixture was stirred under Ar at 70°C for 30 minutes. A solution of compound (16-3) (71 mg) in dry DMF (10 ml) was added dropwise to the reaction mixture over 3 hours. After the addition was complete, the reaction mixture was stirred for an additional 3 hours. The reaction mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous MgSO ４ The resulting compound (17-4A) was separated from the compound (17-4B) by silica gel chromatography, and finally the compound (17-4A) was obtained.

[0209] Compound (17-4A) (50 mg) CHCl ３ To the (10 ml) solution, 4-pyridylacetonitrile hydrochloride (3 equivalents of compound (17-4A)) and piperidine were added. The reaction mixture was refluxed for 4 hours. After that, the reaction mixture was cooled to room temperature, and the solvent was dried on a rotary evaporator. The crude mixture was then purified by silica gel chromatography to obtain organic compound (17) (42% yield). ５３ H ４１ N ５ S ２ [M] ＋ Exact Mass=811.28 MS (MALDI-TOF)=811.43.

[0210] Organic compound (17) １ H NMR (CDCl ３ , 600 MHz) gave the following results: δ 8.72 (d, 2H, J = 6.18 Hz), 8.31 (d, 1H, J = 4.02 Hz), 8.13 (d, 1H, J = 7.44 Hz), 8.06 (d, 2H, J = 8.28 Hz), 7.92 (s, 1H), 7.87-7.85 (m, 2H), 7.75 (d, 2H, J = 8.28 Hz), 7.60-7.58 (m, 4H), 7.41-7.45 (m, 4H), 7.27 (s, 1H), 7.15-7.19 (m, 3H), 1.72 (s, 12H), 1.68 (s, 6H).

[0211] The measurement results and evaluation results of the organic compound (17) are shown in Table 1.

[0212]

[0213]

[0214]

[0215]

[0216]

[0217]

[0218] [Example 7] Organic compound (18) represented by formula (18) was synthesized. ９８H1 １５ N ５ O ２ S ３ [M] ＋ Exact Mass=1489.8 MS(MALDI-TOF)=1489.9.

[0219] Organic compound (18) １ H NMR (CDCl ３ , 600 MHz) gave the following results: δ = 9.86 (s, 1H), 8.30 (s, 1H), 8.02 (s, 4H), 7.68 (s, 2H), 7.50-7.58 (m, 6H), 6.98-7.12 (m, 9H), 4.92 (s, 6H), 4.06 (s, 4H), 3.68 (s, 6H), 1.85 (s, 6H), 1.61 (s, 12H), 1.32 (s, 18H), 0.91 (s, 18H), 0.65 (s, 9H), 0.50 (s, 9H).

[0220] The measurement results and evaluation results of the organic compound (18) are shown in Table 2.

[0221]

[0222] [Example 8] An organic compound (19) represented by formula (19) was synthesized. １１５ H １２５ N ５ O ２ S ４ [M] ＋ Exact Mass=1735.9 MS(MALDI-TOF)=1735.8.

[0223] Organic compound (19) １ H NMR (CDCl ３ , 600 MHz), the analytical results were as follows: δ = 8.66 (s, 1H), 8.31 (s, 1H), 7.79 (s, 1H), 7.71 (s, 2H), 7.51 (d, 6H, J = 4.14), 7.43 (s, 2H), 7.28-7.31 (m, 8H), 7.15-7.23 (m, 8H), 7.06-7.10 (m, 6H), 4.93 (s, 7H), 4.06 (s, 4H), 3.09 (d, 18H, J = 7.20), 1.41 (t, 39H, J = 7.32 Hz), 1.25 (s, 4H), 0.64 (s, 9H), 0.49 (s, 9H).

[0224] The measurement results and evaluation results of the organic compound (19) are shown in Table 2.

[0225]

[0226] Example 9 The organic compound (20) represented by formula (20) was synthesized as follows: Compound (13-2) (see Example 2, 165 mg), 18-crown-6 (10 mg), K ２ CO ３ (300 mg, 2.17 mmol) and dry DMF (50 ml) ２ A solution of compound (16-3) (see Example 5, 144 mg) in dry DMF (30 ml) was added dropwise under atmospheric pressure at 80° C. over 3 hours. The reaction mixture was stirred at 80° C. for 3 hours. The reaction mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous MgSO ４ The mixture was dried at 4°C for 1 hour. The mixture was purified by silica gel chromatography to give compound (20-1) as an orange solid (121 mg, 60% yield). ５９ H ４６ NOS ４ [M+H] ＋ Exact Mass=912.3 MS(MALDI-TOF)=912.3.

[0227] Compound (20-1) (121 mg), 2-(pyridin-4-yl)acetonitrile (142 mg), piperidine (0.1 ml), and CHCl ３ (30 ml) of the mixture was added to N ２ Heated under atmosphere overnight at 70° C. Evaporation of the solvent and purification by silica gel chromatography gave organic compound (20) as a dark red solid (82 mg, 48% yield).

[0228] of organic compound (20) １ H NMR (CDCl ３, 600 MHz) gave the following results: δ 1.64 (s, 6H), 1.66 (s, 12H), 6.88-6.97 (m, 2H), 7.07-7.19 (m, 6H), 7.26-7.34 (m, 11H), 7.36-7.41 (m, 4H), 7.46 (s, 2H), 7.50 (brs, 3H), 7.77 (s, 1H), 8.65 (brs, 2H).

[0229] The measurement results and evaluation results of the organic compound (20) are shown in Table 2.

[0230]

[0231]

[0232] Example 10 Organic compound (21) represented by formula (21) was synthesized as follows: A mixture of compound (21-1) (prepared with reference to Journal of Materials Chemistry C: Materials for Optical and Electronic Devices, 2014, 2(11), 2069-2081) (920 mg) and THF (30 ml) was heated at −78° C. under N ２ After 1 hour, 1.6 M (hexane solution) n-BuLi (2.33 ml) was added at −78° C. over 30 minutes, and then N ２ The reaction was carried out at −78° C. for 2 hours under atmospheric pressure. Then, dry DMF (2 ml) was added, and the mixture was stirred under N ２ The reaction was carried out under atmospheric pressure at -78°C for 2 hours. After the reaction, the temperature was gradually raised to room temperature and the reaction was carried out for 16 hours. Ice water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with water and extracted with anhydrous MgSO ４ The mixture was dried at 400°C. The mixture was purified by silica gel chromatography to give compound (21-2) as a pale yellow solid (400 mg, 52% yield). １９ H １２ NO [M+H] ＋ Exact Mass=270.3 MS(MALDI-TOF)=270.1.

[0233] A mixture of compound (21-2) (400 mg), MeOH (100 ml), and dry THF (50 ml) was added with N ２ NaBH４ (113 mg) was added. After 2 h, the mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous Na ２ SO ４ The solvent was removed to give the crude product (403 mg), which was used in the next step without further purification. ３ A mixture of HBr (506 mg) and dry toluene (100 ml) was ２ The mixture was refluxed under atmospheric pressure for 2 hours. After drying, the mixture was washed with cooled toluene to obtain compound (21-3) as a pale yellow powder (807 mg, 91% yield for two steps). ３７ H ２７ BrNP[M] ＋ Exact Mass=596.5 MS(MALDI-TOF)=596.3

[0234] [2,2':5',2''-terthiophene]-5,5''-dicarboxaldehyde (350 mg), 18-crown-6 (30 mg), K ２ CO ３ (1.0 g) and dry DMF (50 ml) ２ A solution of compound (21-3) (250 mg) in dry DMF (100 ml) was added dropwise under atmospheric pressure at 80° C. over 3 hours. The reaction mixture was stirred at 80° C. for an additional 3 hours. The reaction mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous MgSO ４ The mixture was dried at rt. Purification by silica gel chromatography gave compound (21-4) as an orange solid (95 mg, 42% yield). ３３ H ２０ NOS ３ [M+H] ＋ Exact Mass=542.7 MS(MALDI-TOF)=542.9

[0235] Compound (21-4) (80 mg), 2-(pyridin-4-yl)acetonitrile (177 mg), piperidine (0.1 ml), and CHCl ３(30 ml) of the mixture was added to N ２ The mixture was heated at 70° C. under atmospheric pressure overnight. After cooling, the reaction mixture was quenched with water and extracted with THF. The organic layer was washed with saturated brine and anhydrous Na ２ SO ４ The residue was dried at rt and purified by silica gel chromatography to give the organic compound (21) as a dark red solid (46 mg, 48% yield).

[0236] Organic compound (21) １ H NMR (CDCl ３ , 600 MHz) gave the following results: δ 7.15-7.18 (m, 1H), 7.30-7.34 (m, 2H), 7.39-7.45 (m, 4H), 7.45-7.59 (m, 4H), 7.58-7.75 (m, 5H), 8.11-8.27 (m, 4H), 8.38 (s, 1H), 8.65 (d, J = 2.2 Hz, 2H).

[0237] The measurement results and evaluation results of the organic compound (21) are shown in Table 2.

[0238]

[0239]

[0240]

[0241]

[0242]

[0243] Example 11 Organic compound (22) represented by formula (22) was synthesized as follows: Compound (13-2) (250 mg), 18-crown-6 (10 mg), K ２ CO ３ (1.0 g) and dry DMF (50 ml) ２ A solution of compound (21-3) (298 mg) in dry DMF (30 ml) was added dropwise under atmospheric pressure at 80° C. over 3 hours. The reaction mixture was stirred at 80° C. for 3 hours. The reaction mixture was quenched with water and ２ Cl ２ The organic layer was washed with saturated brine and extracted with anhydrous MgSO ４The mixture was dried at 40°C for 1 hour. Purification by silica gel chromatography gave the organic compound (22-1) as an orange solid (140 mg, 35% yield). ５０ H ３０ NOS ４ [M+H] ＋ Exact Mass=803.1 MS(MALDI-TOF)=803.1

[0244] Compound (22-1) (140 mg), 2-(pyridin-4-yl)acetonitrile (201 mg), piperidine (0.1 ml), and CHCl ３ (30 ml) of the mixture was added to N ２ Heated under atmosphere overnight at 70° C. Evaporation of the solvent and purification by silica gel chromatography gave organic compound (22) as a dark red solid (84 mg, 55% yield).

[0245] Organic compound (22) １ H NMR (CDCl ３ , 600 MHz) gave the following results: δ 7.08-7.45 (m, 18H), 7.45-7.75 (m, 8H), 8.10-8.16 (m, 2H), 8.20-8.26 (m, 2H), 8.36 (s, 1H), 8.64 (brs, 2H).

[0246] The measurement results and evaluation results of the organic compound (22) are shown in Table 2.

[0247]

[0248]

[0249] [Example 12] The organic compound (23) represented by the formula (23) was synthesized as follows: Compound (17-4B) (56 mg) was dissolved in CHCl ３ To the (10 ml) solution, 2-(pyridin-4-yl)acetonitrile (3 equivalents relative to compound (17-4B)) and piperidine were added. The reaction mixture was refluxed for 4 hours. Thereafter, the reaction mixture was cooled to room temperature, and the solvent was removed using a rotary evaporator. The resulting mixture was then purified by silica gel chromatography to obtain organic compound (23) (40% yield). ５３ H ４１ N5S2[M]＋ Exact Mass=811.3 MS(MALDI-TOF)=811.5

[0250] Organic compound (23) １ H NMR (CDCl ３ , 600 MHz), the analytical results were as follows: δ 8.73 (d, 2H, J = 5.04 Hz), 8.18 (d, 2H, J = 8.46 Hz), 8.12-8.14 (m, 3H), 7.98 (d, 1H, J = 7.44 Hz), 7.85 (d, 1H, J = 7.5 Hz), 7.80 (s, 1H), 7.62 (d, 2H, J = 6.12 Hz), 7.53 (s, 2H), 7.42-7.39 (m, 4H), 7.23-7.11 (m, 5H), 1.68 (s, 12H), 1.65 (s, 6H).

[0251] The measurement results and evaluation results of the organic compound (23) are shown in Table 2.

[0252]

[0253]

[0254]

[0255] Comparative Example 1 Compound (26) was prepared. Bis(tetrabutylammonium)dihydrogenbis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II)), manufactured by Sigma-Aldrich, 95% (NMR), was used as compound (26).

[0256] The measurement results and evaluation results of compound (26) are shown in Table 3. In Table 3, "-" indicates that no measurement was performed.

[0257]

[0258] Comparative Example 2 Compound (27) was synthesized as follows: A mixture of compound (12-4) (100 mg), cyanoacetic acid (100 mg), ammonium acetate (10 mg), dry THF (6 ml) and glacial acetic acid (24 ml) was added to a 1000 ml ethanol solution. ２The mixture was heated at 70° C. under atmospheric pressure overnight. After cooling, the reaction mixture was quenched with water and extracted with THF. The organic layer was washed with saturated brine and anhydrous Na ２ SO ４ The residue was dried at rt and purified by silica gel chromatography to give compound (27) as a dark red solid (66 mg, 60% yield).

[0259] Compound (27) １ H NMR (CDCl ３ The analytical results using a frequency band (600 MHz) were as follows: δ 0.88 (t, J = 6.8 Hz, 3H), 1.21-1.46 (m, 24H), 1.48-1.63 (m, 2H), 1.78-1.92 (m, 2H), 4.07 (t, J = 6.3 Hz, 2H), 7.06 (d, J = 3.7 Hz, 1H), 7.13-7.51 (m, 14H), 7.61 (d, J = 8.4 Hz, 1H), 7.79 (d, J = 4.0 Hz, 1H), 8.16 (d, J = 7.5 Hz, 1H), 8.30-8.36 (m, 2H).

[0260] The measurement results and evaluation results of compound (27) are shown in Table 3.

[0261]

[0262] [Comparative Example 3] Compound (28) was synthesized as follows: Compound (12-4) (100 mg), 2-(1H-tetrazol-5-yl)acetonitrile (139 mg), piperidine (0.1 ml), and CHCl ３ (30 ml) of the mixture was added to N ２ The mixture was heated at 80° C. under atmospheric pressure overnight. After cooling, the reaction mixture was quenched with water and extracted with THF. The organic layer was washed with saturated brine and anhydrous Na ２ SO ４ The residue was dried at rt and purified by silica gel chromatography to give compound (28) as a dark red solid (59 mg, 52% yield).

[0263] Compound (28) １ H NMR (CDCl ３The analytical results by NMR (600 MHz) were as follows: δ 0.89-0.96 (m, 3H), 1.25-1.50 (m, 24H), 1.55-1.60 (m, 2H), 1.87-1.93 (m, 2H), 4.10-4.15 (m, 2H), 7.09-7.46 (m, 12H), 7.46-7.53 (m, 3H), 7.63-7.68 (m, 2H), 7.82 (s, 1H), 8.19-8.12 (m, 1H), 8.37 (s, 1H), 8.56 (s, 1H).

[0264] The measurement results and evaluation results of compound (28) are shown in Table 3.

[0265]

[0266] Comparative Example 4 Compound (29) was synthesized as follows: A mixture of compound (12-4) (0.15 mmol), 2-(4-bromophenyl)acetonitrile 34 (30 mg), tetrabutylammonium hydroxide (0.1 ml), and EtOH / THF (100 ml / 50 ml) was dissolved in N ２ The mixture was heated at 80° C. under atmospheric pressure overnight. After cooling the reaction mixture, the reaction was quenched with water and extracted with THF. The organic layer was dried and ２ Cl ２ The resulting mixture was recrystallized from -EtOH to give compound (29-1) as a red solid (121 mg, 84% yield). ５７ H ５８ BrN ２ OS ３ [M+H] ＋ Exact Mass=962.2 MS(MALDI-TOF)=962.1

[0267] Compound (29-1) (50 mg), SiH (OEt) ３ (25 mg), Pd ２ (dba) ３ (2.7 mg), 2-(di-tert-butylphosphino)biphenyl (10.8 mg), tetrabutylammonium iodide (37 mg), N,N-diisopropylethylamine (39 mg), and dry DMF (4 ml) were added to a mixture of N ２The mixture was heated under atmosphere at 80° C. for 24 hours. After cooling, the reaction mixture was dried and purified by silica gel chromatography to give compound (29) as a reddish-orange solid (21 mg, 39% yield).

[0268] Compound (29) １ H NMR (CDCl ３ , 400 MHz), the analytical results were as follows: δ 0.89 (t, J = 3.3 Hz, 3H), 1.20-1.44 (m, 33H), 1.46-1.57 (m, 2H), 1.79-1.90 (m, 2H), 3.89 (dd, J = 3.5, 10.5 Hz, 6H), 4.06 (t, J = 3.2 Hz, 2H), 6.96-6.18 (m, 1H), 7.06-7.14 (m, 4H), 7.14-7.24 (m, 3H), 7.27-7.51 (m, 10H), 7.51-7.76 (m, 4H), 8.15 (d, J = 3.8 Hz, 1H), 8.20 (s, 1H).

[0269] The measurement results and evaluation results of compound (29) are shown in Table 3.

[0270]

[0271]

[0272] Comparative Example 5 Compound (30) was synthesized as follows: A mixture of compound (12-4) (67 mg), diethyl cyanomethylphosphonate (151 mg), piperidine (0.1 ml), and THF (30 ml) was added to a N ２ The mixture was heated at 70° C. under atmospheric pressure overnight. After cooling the reaction mixture, the reaction was quenched with water and extracted with THF. The organic layer was washed with saturated brine and anhydrous Na ２ SO ４ The residue was dried at rt and purified by silica gel chromatography to give compound (30) as a dark red solid (44 mg, 55% yield).

[0273] Compound (30) １ H NMR (CDCl ３The analytical results by a frequency (Hz) of 600 MHz were as follows: δ 0.89 (t, J = 3.4 Hz, 3H), 1.22-1.37 (m, 22H). 1.48-1.53 ​​(m, 2H), 1.38-1.44 (m, 6H), 1.47-1.60 (m, 2H), 1.82-1.89 (m, 2H ), 4.06-4.08 (m, 2H), 4.17-4.27 (m, 4H), 7.00 (d, J = 1.9Hz, 1H), 7.07-7.24 ( m, 6H), 7.28-7.34 (m, 5H), 7.39-7.45 (m, 3H), 7.56 (d, J = 4.3Hz, 1H), 7.60 ( d, J=2.0Hz, 1H), 8.03 (d, J=9.8Hz, 1H), 8.15 (d, J=3.9Hz, 1H), 8.23 ​​(s, 1H).

[0274] The measurement results and evaluation results of compound (30) are shown in Table 3.

[0275]

[0276]

[0277] [Example 13] In Example 5, the first cell carrying the synthesized organic compound (16) was used, but the first cell was replaced with the second cell, and measurements and evaluations were carried out. The measurement results and evaluation results are shown in Table 4.

[0278] [Example 14] In Example 3, the first cell carrying the synthesized organic compound (14) was used, but the first cell was replaced with the second cell, and measurements and evaluations were carried out. The measurement results and evaluation results are shown in Table 4.

[0279]

[0280] [Example 15] In Example 5, the first cell carrying the synthesized organic compound (16) was used, but the first cell was replaced with the third cell for measurement and evaluation. The measurement results and evaluation results are shown in Table 5.

[0281] [Examples 16 to 19] Compounds (32) to (35) were synthesized as follows.

[0282]

[0283] The compound (16-1) (183 mg), chloroform (5 mL), and glacial acetic acid (5 mL) were added to a 50 mL round-bottom flask, and N-iodosuccinimide (113 mg) was added over 30 minutes. After 6 hours, the mixture was quenched with sodium bicarbonate and washed with water. The organic layer was then extracted with anhydrous Na ２ SO ４ After drying at 40°C, the organic solvent was concentrated to give the above compound (32-2) as a pale yellow powder (235 mg).

[0284]

[0285] In a 50 mL round-bottom flask, the above compound (32-2) (688 mg), ethanethiol (173 mg), tBuONa (300 mg), nBuOH (20 mL), Pd(PPh ３ ) ４ (100 mg) was added under a nitrogen atmosphere and refluxed for 24 hours. After the reaction, insoluble matter was filtered through Celite, the solvent was evaporated, and the residue was subjected to recycle preparative HPLC (JAIGEL-HR-P, chloroform solvent) to obtain the above compound (32-3) as a yellow liquid (227 mg, yield 38%).

[0286] Compound (32-3) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 7.43-7.37 (m, 6H), 7.17-7.10 (m, 2H), 2.54 (dd, J=7.1, 14.2Hz, 2H), 1.62 (brs, 18H), 1.02 (t, J=7.2Hz, 3H)

[0287] The above compound (33-3) was obtained in a 57% yield in the same manner as above, except that n-hexanethiol was used instead of ethanethiol in the above procedure for obtaining compound (32-3).

[0288] Compound (33-3) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３, 400MHz): 7.40-7.35 (m, 6H), 7.15-7.09 (m, 2H), 2.87 (dd, J=7.3, 14.7 Hz, 2H), 1.62 (s, 6H), 1.61 (s, 12H), 1.48-1.23 (m, 8H), 0.86 (t, J=7.0Hz ,3H)

[0289] Compound (34-3) was obtained in the same manner as above, except that n-decanethiol was used instead of ethanethiol, to obtain compound (32-3) (yield 59%). Ｈ (CDCl ３ , 400MHz): 7.42-7.37 (m, 6H), 7.17-7.11 (m, 2H), 2.90-2.86 (m, 2H), 1.67-1.61 (s, 18H), 1.47-1.23 (m, 16H), 0.88 (t, J=6.6Hz, 3H)

[0290] Compound (35-3) was obtained in the same manner as above, except that n-tetradecanethiol was used instead of ethanethiol, to obtain compound (32-3) (yield 41%). Ｈ (CDCl ３ , 400MHz): 7.44-7.36 (m, 6H), 7.13-7.12 (m, 2H), 2.90 (dd, J=7.1, 14.3Hz, 2H), 1.65 (s, 6H), 1.64 (s, 12H), 1.48-1.19 (m, 24H), 0.89 (t, J=5.7Hz, 3H)

[0291]

[0292] DMF (6 mL) was added to a 50 mL round-bottom flask, and phosphorus oxychloride (3 mL) was added in an ice bath. The mixture was stirred for 1 hour at room temperature under a nitrogen atmosphere. A solution of compound (32-3) (210 mg / L) in 1,2-dichloroethane (20 mL) was added all at once, and the mixture was heated and stirred at 40°C. After confirming the disappearance of the starting materials by TLC, the mixture was poured into ice water and stirred for 1 hour. The aqueous layer was extracted with dichloromethane and washed with water. The organic layer was then washed with anhydrous NaCl. ２ SO ４ After the solvent was evaporated, the residue was subjected to recycling preparative HPLC (JAIGEL-HR-P, chloroform solvent) to obtain compound (32-4) as a yellow liquid (161 mg, 72%).

[0293] Compound (32-4) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 9.92 (s, 1H), 7.92-7.89 (s, 2H), 7.46-7.40 (m, 4H), 7.25-7.19 (m, 1H), 3.0-2.9 (m, 2H), 1.66 (brs, 18H), 1.35-1.29 (m, 3H)

[0294] Compound (33-4) was obtained in a 59% yield in the same manner as above, except that compound (33-3) was used instead of compound (32-3).

[0295] Compound (33-4) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 9.95 (s, 1H), 7.90 (s, 2H), 7.48-7.40 (m, 4H), 7.26-7.19 (m, 1H), 2.94 (t, J=7.3Hz, 2H), 1.69-1.65 (m, 18H), 0.88 (t, J=6.5Hz, 3H)

[0296] Compound (34-4) was obtained in the same manner as above, except that compound (34-3) was used instead of compound (32-3) (yield 63%).

[0297] Compound (34-4) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 9.95 (s, 1H), 7.90 (s, 2H), 7.48-7.40 (m, 4H), 7.26-7.19 (m, 1H), 2.94 (t, J=7.3Hz, 2H), 1.69-1.65 (m, 18H), 0.88 (t, J=6.5Hz, 3H)

[0298] Compound (35-4) was obtained in a yield of 83% in the same manner as above, except that compound (35-3) was used instead of compound (32-3).

[0299] Compound (35-4) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 9.92 (s, 1H), 7.90 (s, 2H), 7.87 (d, J=2.0Hz, 2H), 7.44-7.36 (m, 4H), 7.23-7.15 ( m, 1H), 2.91 (t, J=7.1Hz, 2H), 1.70-1.61 (m, 18H), 1.47-1.21 (m, 24H), 0.87 (t, J=6.9Hz, 3H)

[0300]

[0301] Compound (32-4) (155 mg), dichloromethane (10 mL), and methanol (10 mL) were added to a 50 mL round-bottom flask, and NaBH ４ (13 mg) was added in one portion and stirred. After 2 hours, the reaction solution was poured into ice water and stirred for 1 hour. The aqueous layer was extracted with dichloromethane and washed with water. The organic layer was then washed with anhydrous Na ２ SO ４ The mixture was dried at rt. The solvent was evaporated to give a crude product (151 mg). To this crude product (151 mg), triphenylphosphine hydrogen bromide (114 mg) and anhydrous toluene (15 mL) were added, and the mixture was heated under reflux for 12 hours. After the reaction, the solvent was evaporated to give compound (32-5) as a colorless syrup (258 mg, yield 90%).

[0302] Compound (32-5) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３, 400MHz): 7.86-7.80 (m, 3H), 7.73-7.63 (m, 12H), 7.42-7.30 (m, 4H), 7.17-7.10 (m, 3H), 5.19 (d, J=13.6Hz), 2.93 (dd, J=7.3, 14.6Hz) 1.64-1 .. 61 (m, 18H), 0.87 (t, J=6.7Hz, 3H)

[0303] Compound (33-5) was obtained in a 80% yield in the same manner as above, except that compound (33-4) was used instead of compound (32-4).

[0304] Compound (33-5) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 7.82-7.61 (m, 15H), 7.42-7.28 (m, 4H), 7.21-7.09 (m, 3H), 5.44 (d, J=13.7H z), 2.91 (t, J=7.3Hz, 2H), 1.67-1.60 (m, 18H), 1.48-1.34 (m, 8H), 0.89 (t, J=6.5Hz, 3H)

[0305] Compound (34-5) was obtained in the same manner as above, except that compound (34-4) was used instead of compound (32-4) (yield 94%).

[0306] Compound (34-5) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 7.80-7.56 (m, 15H), 7.39-7.27 (m, 4H), 7.20-7.09 (m, 3H), 5.43 (d, J=1 3.7Hz, 2H), 1.69-1.58 (m, 18H), 1.47-1.21 (m, J=7.3, 16H), 0.86 (t, J=6.5Hz, 3H)

[0307] Compound (35-5) was obtained in the same manner as above, except that compound (35-4) was used instead of compound (32-4) (yield 91%).

[0308] Compound (35-5)１ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 7.89-7.63 (m, 15H), 7.42-7.30 (m, 4H), 7.17-7.09 (m, 3H), 5.22-5.09 (m, 2H ), 2.89 (t, J=7.3Hz, 3H), 1.66-1.59 (m, 18H), 1.47-1.23 (m, 32H), 0.88 (t, J=6.2Hz, 3H)

[0309]

[0310] In a 100 mL round-bottom flask, [2,2':5',2''-terthiophene]-5,5''-dicarboxaldehyde (194 mg), K ２ CO ３ (100 mg), 18-crown-6 (10 mg), and DMF (30 mL) were added. To this was added dropwise a solution of compound (32-5) (250 mg) in DMF (30 mL) at 80°C under a nitrogen atmosphere over 4 hours. After the dropwise addition, the mixture was heated and stirred at 80°C under a nitrogen atmosphere for 2 hours. After the reaction, insoluble matter was filtered through Celite, and the solvent was evaporated. The mixture was then subjected to recycling preparative HPLC (JAIGEL-HR-P, chloroform solvent) to obtain compound (32-6) as an orange compound (144 mg, yield 62%).

[0311] Compound (32-6) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 9.89 (s, 1H), 7.71 (d, J=4.0Hz, 1H), 7.52-7.39 (m, 6H), 7.31 (d, J=3.9Hz, 1H), 7.27 (d, J=3.9Hz, 1H), 7.20-7.13 (m, 4H), 7.03-6.95 (m, 2H), 2.95 (dd, J=7.4, 14.7Hz, 2H), 1.73-1.63 (m, 18H), 0.90 (t, J=6.6Hz, 3H)

[0312] Compound (33-6) was obtained in the same manner as above, except that compound (33-5) was used instead of compound (32-5) (yield 71%).

[0313] Compound (33-6) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 9.84 (s, 1H), 7.68 (d, J=4.0Hz, 1H), 7.52-7.38 (m, 6H), 7.34-7.25 (m, 3H), 7.19-7.14 (m, 3H), 7. 03-6.98 (m, 2H), 2.52 (dd, J=7.1, 14.3Hz, 2H), 1.69-1.62 (m, 18H), 1.49-1.23 (m, 8H), 0.88 (t, J=6.8Hz, 3H)

[0314] Compound (34-6) was obtained in a 12% yield in the same manner as above, except that compound (34-5) was used instead of compound (32-5).

[0315] Compound (34-6) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 600MHz): 9.88 (s, 1H), 7.6 (d, J=1.8Hz, 1H), 7.52-7.39 (m, 6H), 7.34-7.25 (m, 2H), 7.20-7.13 (m, 4H), 7.03-6.96 (m, 2H), 2.93 (t, J=7.3Hz, 2H), 1.73-1.64 (m, 18H), 1.49-1.21 (m, 16H), 0.89 (t, J=4.8Hz, 3H)

[0316] Compound (35-6) was obtained in the same manner as above, except that compound (35-5) was used instead of compound (32-5) (yield: 76%).

[0317] Compound (35-6) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３, 400MHz): 9.87 (s, 1H), 7.68 (d, J=4.0Hz, 1H), 7.47-7.36 (m, 4H), 7.30-7.23 (m, 2H), 7.18-7.10 (m, 4H), 7.00-6.94 (m, 2H), 2.90 (dd, J=7.4Hz, 2H), 1.69-1.62 (m, 18H), 1.47-1.21 (m, 24H), 0.86 (t, J=6.6Hz, 3H)

[0318]

[0319] Compound (32-6) (100 mg), 4-pyridineacetonitrile (60 mg), and chloroform (30 mL) were added to a 100 mL round-bottom flask and refluxed at 80° C. for 20 hours under a nitrogen atmosphere. After the reaction, the solvent was distilled off and the resulting mixture was subjected to recycle preparative HPLC (JAIGEL-HR-P, chloroform solvent) to obtain compound (32) as a deep red compound (84 mg, yield 73%).

[0320] Compound (32) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 8.69-8.66 (m, 2H), 7.80 (s, 1H), 7.61-7.37 (m, 9H), 7.32-7.22 (m, 2H), 7.17-7.11 (m, 4H), 7.01-6.92 (m, 2H), 2.93 (dd, J=7.4, 14.7Hz, 2H), 1.68-1.62 (m, 18H), 1.31 (t, J=7.3Hz, 3H)

[0321] Compound (33) was obtained in the same manner as above, except that compound (33-6) was used instead of compound (32-6) (yield 61%).

[0322] Compound (33) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３, 400MHz): 8.68 (brs, 2H), 7.80 (s, 1H), 7.61-7.36 (m, 9H), 7.32-7.21 (m, 2H), 7.18-7.10 (m, 4H) ), 7.01-6.92 (m, 2H), 2.89 (t, J=7.4Hz, 2H), 1.68-1.62 (m, 18H), 1.48-1.24 (m, 8H), 0.88 (t, J=6 .7Hz, 3H)

[0323] Compound (34) was obtained in the same manner as above, except that compound (34-6) was used instead of compound (32-6) (yield 71%).

[0324] Compound (34) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 8.67 (d, J=6.2Hz, 2H), 7.80 (s, 1H), 7.61-7.36 (m, 9H), 7.33-7.21 (m, 2H), 7.18-7.11 (m, 4H), 7.02-6.92 (m, 2H), 2.89 (t, J=7.4Hz, 2H), 1.72-1.61 (m, 18H), 1.48-1.22 (m, 16H), 0.87 (t, J=6.7Hz, 3H)

[0325] Compound (35) was obtained in the same manner as above, except that compound (35-6) was used instead of compound (32-6) (yield 79%).

[0326] Compound (35) １ H NMR (CDCl ３ The analytical results by the frequency (Hz) were as follows: Ｈ (CDCl ３ , 400MHz): 8.70 (brs, 2H), 7.82-7.81 (m, 1H), 7.61-7.36 (m, 9H), 7.32-7.21 (m, 2H), 7.18-7.12 (m, 4H), 7.01-6.93 (m, 2H), 2.93 (t, J=7.3Hz, 2H), 1.68-1.63 (m, 18H), 1.50-1.22 (m, 24H), 0.90 (t, J=6.6Hz, 3H)

[0327] The measurement results and evaluation results of the organic compounds (32) to (36) are shown in Table 5.

[0328]

[0329] [3] Evaluation The organic compounds obtained in Examples 1 to 19 had long-wavelength absorption edges extending into long wavelengths, confirming that they can be suitably used as sensitizing dyes. When hydrogen was produced using a semiconductor thin-film electrode using the organic compounds obtained in Examples 1 to 19 as sensitizing dyes, the STH was higher than in the comparative example, confirming that they are suitable as semiconductor thin-film electrodes for photoelectrolysis. A photoelectrolytic cell using the anode 10 shown in FIG. 1 , which is one embodiment of the present disclosure, measured a higher STH, confirming that it can be used practically as a photoelectrolysis cell for photoelectrolysis.

[0330] The disclosures of Japanese Patent Application No. 2024-106715 filed on July 2, 2024 and Japanese Patent Application No. 2025-014374 filed on January 30, 2025 are incorporated herein by reference in their entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. An organic compound represented by the following general formula (1): [In general formula (1), X contains at least one linking group selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 10 carbon atoms and a substituted or unsubstituted aromatic heterocyclic group having 4 to 8 carbon atoms, and when a plurality of linking groups are contained, the plurality of linking groups are linked to each other via carbon atoms; Y is a single bond or a substituted or unsubstituted aliphatic hydrocarbon linking group having 1 to 4 carbon atoms; Ar is a substituted or unsubstituted aromatic heterocyclic group having 5 to 9 carbon atoms, and the number of carbon atoms constituting the aromatic heterocyclic group is 2 or more; R １ and R ２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms, ３ , R ４ , R ５ and R ６ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms; R ３ and R ５ and R ４ and R ６ may be bonded to each other to form a substituted or unsubstituted ring, and the formed ring may contain a sulfur atom.] 2. The organic compound according to claim 1, wherein in the general formula (1), Ar is an unsubstituted pyridyl group or a pyridyl group substituted with an alkyl group having 1 to 4 carbon atoms.

3. In the general formula (1), R ３ , R ４ , R ５ and R ６ The organic compound according to claim 1 , wherein the organic compound forms a structure represented by the following general formula (2): [In general formula (2), R １ and R ２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms; Z １ , Z ２ and Z ３ are each independently a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 5 carbon atoms, an oxygen atom, or a sulfur atom; ７ , R ９ , R １０ and R １２ are each independently a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms, ８ and R １１ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, or an unsubstituted alkylsulfanyl group having 1 to 20 carbon atoms.

4. In the general formula (2), Z １ , Z ２ and Z ３ The organic compound according to claim 3, wherein:

5. In the general formula (2), R ８ and R １１ wherein one of the above is a substituted or unsubstituted alkoxy group having 2 to 12 carbon atoms or an unsubstituted alkylsulfanyl group having 2 to 12 carbon atoms, and the other is a hydrogen atom or a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 3 carbon atoms.

6. The organic compound according to claim 2, wherein in the general formula (1), X contains two or more linking groups selected from the group consisting of the following formulas (4) to (7): [In formula (7), Z ４ is an oxygen atom or a sulfur atom.

7. The organic compound according to claim 2, wherein X in the general formula (1) contains a linking group represented by the following formula (5A) or (5B): [In formula (5A) and formula (5B), * represents a bonding site with Y.] 8. The organic compound according to claim 2, wherein in the general formula (1), X is a linking group of any one of formulas (8) to (10). [In formulas (8) to (10), * represents a bonding site with Y.] 9. The organic compound according to claim 1, wherein Y in the general formula (1) is a linking group represented by the following formula (11):

10. The organic compound according to claim 1, which is a dye.

11. A photocatalyst for water electrolysis, comprising the organic compound according to any one of claims 1 to 10 and a photocatalyst.

12. A semiconductor thin film electrode comprising the organic compound according to any one of claims 1 to 10 and a compound semiconductor.

13. A photovoltaic water electrolysis cell comprising a negative electrode, a positive electrode and an electrolyte, wherein the negative electrode comprises the semiconductor thin film electrode according to claim 12 and a current collector plate.

14. A method for producing hydrogen using the semiconductor thin film electrode according to claim 12.

15. The method for producing hydrogen according to claim 14, which uses solar cells.

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