p-diphenyl compound derivative mixture and method for producing it

Abstract

To provide an organic semiconductor compound useful as a charge transport material capable of realizing an organic electronic device that exhibits high solubility capable of accommodating a solution process and favorable electrical properties due to excellent charge mobility.SOLUTION: A mixture contains a p-diphenyl compound derivative represented by the general formula (1) in the figure, for example.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a mixture of p-diphenyl compound derivatives and a method for producing the mixture. [Background technology]

[0002] In recent years, devices using organic semiconductor materials with charge-transporting properties (charge refers to electrons or holes, and the same applies hereinafter) have attracted attention (for example, Patent Document 1, etc.). Organic thin films containing organic semiconductor materials are expected to be applied to organic electronic devices such as organic electroluminescent elements (hereinafter abbreviated as organic EL elements), photoelectric conversion elements such as solar cells and light sensors, and organic thin-film transistors. Compared to cases using inorganic semiconductor materials, they are attractive in terms of being lightweight, easy to fabricate (large area, flexibility), mass-producibility, low cost, and diversity of materials and functions.

[0003] Among the aforementioned organic semiconductor materials, hole-transporting materials and electron-transporting materials capable of forming organic thin films have been extensively studied. For example, in order to commercialize organic EL devices, the device structure has undergone many improvements, and various roles have been further subdivided. High efficiency and durability have been achieved by field-emitting elements in which an anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and cathode are sequentially arranged on a substrate (for example, Patent Document 3).

[0004] Organic light-emitting diodes (OLEDs) emit light when charges injected from both electrodes recombine in the light-emitting layer. Since efficiently transferring both holes and electrons to the light-emitting layer is crucial, charge transport materials play a significant role. Therefore, charge transport materials with high charge injection capabilities and high mobility are in demand.

[0005] Furthermore, organic thin films containing the aforementioned organic semiconductor materials are also being considered for applications in photoelectric conversion. For example, solar cells with photoelectric conversion elements using organic thin films are artificial devices for converting solar energy into electrical energy and are important as technologies for the effective utilization of solar energy. In addition, light-receiving elements such as image sensors are being used not only in television cameras and smartphone cameras, but also in driver assistance systems, and both their applications and markets are expanding.

[0006] However, the conversion efficiency of these organic photoelectric devices is generally known to be significantly lower than that of inorganic semiconductors. Reasons for the low conversion efficiency in organic photoelectric devices include low quantum yield of carrier light generation, low charge mobility, and high resistivity, making the development of organic semiconductor materials that contribute to improving conversion efficiency a key challenge.

[0007] Furthermore, in the development of organic electronic devices using organic thin films, as mentioned above, materials with high charge mobility are required. In this context, various reports have shown that improving the purity of charge transport materials used to form organic thin films has resulted in improved performance of organic EL elements (for example, Patent Document 2). However, there is a need to develop materials that can improve performance while suppressing the increased refining costs required to increase the purity of charge transport materials.

[0008] As described above, currently, no charge transport material has been found that fully satisfies the various properties required for improving the characteristics of organic electronic devices. Furthermore, when manufacturing by solution processes for film formation, high and stable solubility in solvents is necessary, but some materials have not been put into practical use due to poor solubility in solvents. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2012-246484 [Patent Document 2] Japanese Patent Publication No. 2012-089581 [Patent Document 3] International Publication No. 2008 / 062636 [Overview of the project] [Problems that the invention aims to solve]

[0010] The problem that this invention aims to solve is to provide an organic semiconductor compound that is useful as a charge transport material that can realize organic electronic devices exhibiting high solubility to accommodate solution processes and good electrical properties due to excellent charge mobility. [Means for solving the problem]

[0011] To solve the above problems, the inventors focused on p-diphenyl compounds and conducted diligent research, resulting in the discovery of a mixture of p-diphenyl compound derivatives containing compounds represented by the following general formulas (1), (2), and (3), and a method for producing the mixture. In other words, the gist of the present invention is as follows.

[0012] 1. A mixture containing p-diphenyl compound derivatives represented by the following general formulas (1), (2), and (3).

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[0016] [In the formula, R 1 ~R 8 Each of them operates independently. A hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent, a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent, a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent, an amino group having 1 to 20 carbon atoms which may have a substituent, or, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, R 1 and R 2 、R 3 and R 4 、R 5 and R 6 、R 7 and R 8 may be bonded to each other to form a ring. However, at least one type and / or substitution position of the substituents R 5 ~R 8 [[]]END]]shall be different from any of the substituents R 1 ~R 4 . Also, either one of R 1 or R 3 , and either one of R 5 or R 7 shall not be a hydrogen atom.]

[0017] 2. In the general formulas (1), (2) and (3), R 1 , R 3 , R 5 and R 7 is a mixture of a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, or a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent.

[0018] 3. A mixture having a content of 18-30% of the compound represented by the general formula (1) above.

[0019] 4. A mixture having a content of 20-32% of the compound represented by the general formula (2) above.

[0020] 5. A mixture having a content of 45-55% of the compound represented by the general formula (3) above.

[0021] 6. A mixture having a solubility of 50% by weight or more per 100g of organic solvent at room temperature (25±5℃).

[0022] 7. A method for producing a mixture containing the compounds represented by general formulas (1), (2), and (3), obtained by a one-step reaction from the compounds represented by the following general formulas (4), (5), and (6).

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[0026] [In the formula, X represents a halogen atom.]

[0027] 8. In the above general formulas (4) and (5), R 1 , R 3 , R 5 , R 7 The present invention relates to a method for producing a mixture comprising a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms (which may have substituents), or a linear or branched alkoxy group having 1 to 20 carbon atoms (which may have substituents).

[0028] 9. A method for producing a mixture, wherein the one-step reaction is an Ullmann reaction and the reaction temperature is 190-235°C.

[0029] 10. A method for producing a mixture, characterized in that the additive in the Ullmann reaction is an aromatic oxycarboxylic acid compound. [Effects of the Invention]

[0030] According to the present invention, it is possible to provide a mixture of p-diphenyl compound derivatives that can be used as a charge transport material capable of realizing organic electronic devices that exhibit high solubility in organic solvents, excellent mobility, and good electrical properties. [Modes for carrying out the invention]

[0031] The embodiments of the present invention will be described in detail below.

[0032] The compounds represented by general formulas (1), (2), and (3) above, which are derivatives of the p-diphenyl compounds of the present invention, will be described in detail below, but the present invention is not limited to these.

[0033] In general formulas (1), (2), and (3), R 1 ~R 8 Each of them operates independently. Hydrogen atom, halogen atom, Linear or branched alkyl groups having 1 to 20 carbon atoms, which may have substituents. A linear or branched alkenyl group having 2 to 20 carbon atoms, which may have substituents. Cycloalkyl groups having 3 to 10 carbon atoms, which may have substituents. A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have substituents. A cycloalkoxy group having 3 to 10 carbon atoms, which may have substituents. An amino group having 1 to 20 carbon atoms, which may have substituents. Alternatively, it represents an aromatic hydrocarbon group having 6 to 36 carbon atoms, which may have substituents.

[0034] In the present invention, examples of "halogen atoms" include fluorine, chlorine, bromine, and iodine.

[0035] In general formulas (1), (2), and (3), R 1 ~R 8 In the expression "linear or branched alkyl groups having 1 to 20 carbon atoms which may have substituents," specific examples of "linear or branched alkyl groups having 1 to 20 carbon atoms" include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, isopentyl group, n-hexyl group, 2-ethylhexyl group, heptyl group, octyl group, isooctyl group, nonyl group, decyl group, etc., and also includes benzyl group (phenylmethyl group) and phenethyl group (phenylethyl group), which are alkyl groups in which one of the hydrogen atoms of the alkyl group is substituted with an aromatic hydrocarbon group such as a phenyl group.

[0036] In general formulas (1), (2), and (3), R 1 ~R 8 In the expression "linear or branched alkenyl group having 2 to 20 carbon atoms which may have substituents," examples of "linear or branched alkenyl group having 2 to 20 carbon atoms" include vinyl group, 1-propenyl group, allyl group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, 1-hexenyl group, isopropenyl group, isobutenyl group, or linear or branched alkenyl group having 2 to 20 carbon atoms formed by the bonding of multiple such alkenyl groups.

[0037] In general formulas (1), (2), and (3), R 1 ~R 8In the expression "a cycloalkyl group having 3 to 10 carbon atoms which may have substituents," specific examples of "a cycloalkyl group having 3 to 10 carbon atoms" include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, and cyclododecyl group.

[0038] In general formulas (1), (2), and (3), R 1 ~R 8 In the expression "linear or branched alkoxy groups having 1 to 20 carbon atoms that may have substituents," examples of "linear or branched alkoxy groups having 1 to 20 carbon atoms" include methoxy, ethoxy, propoxy, n-butoxy, n-pentyloxy, n-hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, isopropoxy, isobutoxy, s-butoxy, t-butoxy, isooctyloxy, t-octyloxy, phenoxy, tolyloxy, biphenylyloxy, terphenylyloxy, naphthyloxy, anthryloxy, phenanthryloxy, fluorenyloxy, and indenyloxy groups.

[0039] In general formulas (1), (2), and (3), R 1 ~R 8 In the expression "a cycloalkoxy group having 3 to 10 carbon atoms which may have substituents," specific examples of "cycloalkoxy groups having 3 to 10 carbon atoms" include cyclopropoxy groups, cyclobutoxy groups, cyclopentyloxy groups, and cyclohexyloxy groups.

[0040] In general formulas (1), (2), and (3), R 1 ~R 8In the expression "amino group having 1 to 20 carbon atoms which may have substituents," specific examples of "amino group having 1 to 20 carbon atoms" include monosubstituted amino groups such as ethylamino group, acetylamino group, and phenylamino group, and disubstituted amino groups such as diethylamino group, diphenylamino group, and acetylphenylamino group.

[0041] In general formulas (1), (2), and (3), R 1 ~R 8 In the "aromatic hydrocarbon group having 6 to 36 carbon atoms that may have substituents" represented by , specific examples of "aromatic hydrocarbon groups having 6 to 36 carbon atoms" include phenyl group, biphenyl group, terphenyl group, naphthyl group, biphenyl group, anthracenyl group (anthryl group), phenanthryl group, fluorenyl group, indenyl group, pyrenyl group, perilenyl group, fluoranthenyl group, triphenylenyl group, and the like. In this invention, the aromatic hydrocarbon group includes "condensed polycyclic aromatic groups".

[0042] In general formulas (1), (2), and (3), R 1 ~R 8 In the expressions "a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents," "a linear or branched alkenyl group having 2 to 20 carbon atoms which may have substituents," "a cycloalkyl group having 3 to 10 carbon atoms which may have substituents," "a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents," "a linear or branched cycloalkoxy group having 3 to 10 carbon atoms which may have substituents," "an amino group having 1 to 20 carbon atoms which may have substituents," or "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have substituents," the "substituents" specifically include halogen atoms such as fluorine, chlorine, bromine, and iodine atoms; cyano groups; hydroxyl groups; nitro groups; nitroso groups; carboxyl groups; phosphate groups; Carboxylic acid ester groups such as methyl ester groups and ethyl ester groups; Linear or branched alkyl groups having 1 to 20 carbon atoms, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, isopentyl group, n-hexyl group, 2-ethylhexyl group, heptyl group, octyl group, isooctyl group, nonyl group, and decyl group; Linear or branched alkenyl groups with 2 to 20 carbon atoms, such as vinyl groups, 1-propenyl groups, allyl groups, 1-butenyl groups, 2-butenyl groups, 1-pentenyl groups, 1-hexenyl groups, isopropenyl groups, and isobutenyl groups; Linear or branched alkoxy groups with 1 to 20 carbon atoms, such as methoxy, ethoxy, propoxy, t-butoxy, pentyloxy, and hexyloxy groups; Aromatic hydrocarbon groups with 6 to 30 carbon atoms, such as phenyl, naphthyl, anthryl, phenanthryl, and pyrenyl groups; Heterocyclic groups with 5 to 20 ring-forming atoms, such as pyridyl group, pyrimidylinyl group, triazinyl group, thienyl group, furyl group (furanyl group), pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, quinolyl group, isoquinolyl group, naphthylidinyl group, acridinyl group, phenanthrolinyl group, benzofuranyl group, benzothienyl group, oxazolyl group, indolyl group, carbazolyl group, benzoxazolyl group, thiazolyl group, benzothiazolyl group, quinoxalinyl group, benzimidazolyl group, pyrazolyl group, dibenzofuranyl group, dibenzothienyl group, and carbonillyl group; Amino groups having 0 to 20 carbon atoms, including unsubstituted amino groups (-NH2), monosubstituted amino groups such as ethylamino groups, acetylamino groups, and phenylamino groups, or disubstituted amino groups such as diethylamino groups, diphenylamino groups, and acetylphenylamino groups; Thio groups with 0 to 20 carbon atoms, such as unsubstituted thio groups (thiol groups: -SH), methylthio groups, ethylthio groups, propylthio groups, hexa-5-ene-3-thio groups, phenylthio groups, and biphenylthio groups; Examples include the above. These "substituents" may consist of only one or more, and if there are multiple substituents, they may be identical or different from one another. Furthermore, these "substituents" may have further substituents as exemplified above.

[0043] In general formulas (1), (2), and (3), R 1 ~R 8 R represents the substituent as described above, 1 and R 2 , R 3 and R 4 , R 5 and R 6 , R 7 and R 8 These elements may be bonded to each other by single bonds, bonds via oxygen atoms, sulfur atoms, or bonds via nitrogen atoms to form a ring.

[0044] In general formulas (1), (2), and (3), substituent R 5 ~R 8 At least one of the types and / or substitution sites is substituent R 1 ~R 4 It is assumed to be different from any of the following. 1 or R 3 Either one of them, and R 5 or R 7 Assume that one of them is not a hydrogen atom.

[0045] In general formulas (1), (2), and (3), R 1 , R 3 , R 5 and R 7From the viewpoint of increasing charge mobility, it is preferable that the group is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents, an amino group having 1 to 20 carbon atoms which may have substituents, or an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have substituents; more preferably, it is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents, or a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents; and even more preferably, it is a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents.

[0046] In general formulas (1), (2), and (3), R 2 , R 4 , R 6 and R 8 From the viewpoint of increasing charge mobility, it is preferable that the group is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents, an amino group having 1 to 20 carbon atoms which may have substituents, or an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have substituents; more preferably, it is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents, or a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents; and even more preferably, it is a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents.

[0047] Specific examples of compounds represented by the general formulas (1) and (2) of the present invention are shown below, but the present invention is not limited to these. Furthermore, the following exemplary compounds are described with some hydrogen atoms, carbon atoms, etc. omitted, and represent only one example of possible isomers, encompassing all other isomers. In addition, each compound may be a mixture of two or more isomers.

[0048] [ka]

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[0056] Specific examples of compounds represented by the general formula (3) above include the following compounds. However, the present invention is not limited to these compounds.

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[0063] The mixtures of the p-diphenyl compound derivatives of the present invention represented by general formulas (1), (2), and (3) can be synthesized by known methods such as the Ullmann reaction using a copper catalyst and a base, or the Buchwald-Hartwig reaction using a palladium catalyst, but are not limited to these.

[0064] A mixture of p-diphenyl compound derivatives containing the compounds represented by general formulas (1), (2), and (3) of the present invention can be synthesized from halogenated p-diphenyl compounds represented by general formulas (4), (5), and (6) by a one-step reaction as described above.

[0065] R represented by general formulas (4) and (5) 1 ~R 8 Each of them operates independently. Hydrogen atom, halogen atom, Linear or branched alkyl groups having 1 to 20 carbon atoms, which may have substituents. A linear or branched alkenyl group having 2 to 20 carbon atoms, which may have substituents. Cycloalkyl groups having 3 to 10 carbon atoms, which may have substituents. A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have substituents. A cycloalkoxy group having 3 to 10 carbon atoms, which may have substituents. An amino group having 1 to 20 carbon atoms, which may have substituents. Alternatively, it represents an aromatic hydrocarbon group having 6 to 36 carbon atoms, which may have substituents.

[0066] R represented by general formulas (4) and (5) 1 ~R 8 In the above general formulas (1), (2), and (3), R 1 ~R 8 This represents a group equivalent to "a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents," "a linear or branched alkenyl group having 2 to 20 carbon atoms which may have substituents," "a cycloalkyl group having 3 to 10 carbon atoms which may have substituents," "a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents," "a cycloalkoxy group having 3 to 10 carbon atoms which may have substituents," "an amino group having 1 to 20 carbon atoms which may have substituents," or "an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have substituents."

[0067] R represented by General Formula (4) and General Formula (5) 1 ~R 8 In "a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent", "a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent", "a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent", "a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent", "a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent", "an amino group having 1 to 20 carbon atoms which may have a substituent", or "an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent", the "substituent" is the same as the "substituent" in the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by R 1 ~R 8 as described above in the general formulas (1), (2) and (3).

[0068] R represented by General Formula (4) and General Formula (5) 1 ~R 8 represents a substituent as described above, but R 1 and R 2 , R 3 and R 4 , R 5 and R 6 , R 7 and R 8 may be bonded to each other by a single bond, a bond through an oxygen atom, a sulfur atom or a bond through a nitrogen atom to form a ring.

[0069] In General Formula (4) and General Formula (5), at least one type and / or substitution position of the substituents R 5 ~R 8 shall be different from any of the substituents R 1 ~R 4 . Also, either one of R 1 or R 3 and either one of R 5 or R 7 shall not be a hydrogen atom.

[0070] In general formulas (4) and (5), R 1 , R 3 , R 5 and R 7 Preferably, is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents, an amino group having 1 to 20 carbon atoms which may have substituents, or an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have substituents; more preferably is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents, or a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents; and even more preferably is a hydrogen atom, or a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents.

[0071] In general formulas (4) and (5), R 2 , R 4 , R 6 and R 8 Preferably, is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents, an amino group having 1 to 20 carbon atoms which may have substituents, or an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have substituents; more preferably is a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents, or a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents; and even more preferably is a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents.

[0072] The preparation of a mixture of p-diphenyl compound derivatives containing the compounds represented by the general formulas (1), (2), and (3) of the present invention by a one-step reaction using the Ullmann reaction will be described below.

[0073] In the present invention, the copper catalyst is not particularly limited, and known catalysts used in the Ullmann reaction can be used. Specific examples include copper powder, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, copper iodide, cuprous oxide, cupric oxide, copper sulfate, copper nitrate, copper carbonate, copper acetate, and copper hydroxide, with copper powder, cuprous chloride, cuprous bromide, and copper iodide being particularly preferred. In the present invention, the amount of copper catalyst is preferably 0.01 to 1 mole per mole of halogen of the p-diphenyl compound represented by the general formula (6) used as a raw material, and more preferably in the range of 0.05 to 0.5 moles.

[0074] In the present invention, the base is used for dehalogenation and is not particularly limited, but examples of bases that can be used include alkali metal carbonates such as sodium carbonate, lithium carbonate, cesium carbonate, and potassium carbonate; alkali metal phosphates such as sodium phosphate, potassium phosphate, cesium phosphate, and lithium phosphate; alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, potassium hydroxide, and cesium hydroxide; alkaline earth metal hydroxides such as barium hydroxide; and metal alkoxides such as sodium methoxide, sodium ethoxide, sodium tert-butoxide, and potassium tert-butoxide.

[0075] In the present invention, the amount of base used in the reaction is preferably in the range of 1 to 4 moles per mole of halogen of the p-diphenyl compound represented by the general formula (6) used as a raw material, and more preferably in the range of 1.5 to 3 moles. If the amount of base is less than the above range, the yield of the mixture of the present invention will be low. Furthermore, if a large excess of base is added beyond the above range, the post-reaction work becomes complicated and undesirable.

[0076] In the present invention, when the reaction is carried out by the Ullmann reaction, additives can be used. As additives for the Ullmann reaction, compounds that coordinate with the copper of the reaction catalyst can be added to lower the reaction temperature and obtain the target product with high purity. For example, diamine compounds such as phenanthroline, bipyridyl, and cyclohexanediamine, as well as 1,1'-binaphthyl-2,2'-diol and aromatic oxycarboxylic acid compounds can be used.

[0077] In the present invention, it is preferable to use aromatic oxycarboxylic acid compounds, specifically 2-hydroxybenzenecarboxylic acid, 3-methyl-2-hydroxybenzenecarboxylic acid, 4-methyl-2-hydroxybenzenecarboxylic acid, 5-methyl-2-hydroxybenzenecarboxylic acid, 6-methyl-2-hydroxybenzenecarboxylic acid, 3,5-dimethyl-2-hydroxybenzenecarboxylic acid, 5-ethyl-2-hydroxybenzenecarboxylic acid, 5-propyl-2-hydroxybenzenecarboxylic acid, 5-butyl-2-hydroxybenzenecarboxylic acid, 3-tert-butyl-2-hydroxybenzenecarboxylic acid, 5-tert-butyl-2-hydroxybenzenecarboxylic acid, 3,5-di(tert-butyl)-2-hydroxybenzenecarboxylic acid (3,5-di-tert-butylsalicylic acid), 3-hexyl-2-hydroxybenzenecarboxylic acid, Examples include 5-hexyl-2-hydroxybenzenecarboxylic acid, 3-cyclohexyl-2-hydroxybenzenecarboxylic acid, 5-ethenyl-2-hydroxybenzenecarboxylic acid, 5-methoxy-2-hydroxybenzenecarboxylic acid, 5-phenoxy-2-hydroxybenzenecarboxylic acid, 4-nitro-2-hydroxybenzenecarboxylic acid, 4-fluoro-2-hydroxybenzenecarboxylic acid, 5-trifluoromethyl-2-hydroxybenzenecarboxylic acid, 5-cyano-2-hydroxybenzenecarboxylic acid, 2,3-di-hydroxybenzenecarboxylic acid, 2,4-di-hydroxybenzenecarboxylic acid, 2,5-di-hydroxybenzenecarboxylic acid, 4-phenyl-2-hydroxybenzenecarboxylic acid, 5-naphthyl-2-hydroxybenzenecarboxylic acid, 2-hydroxynaphthalene-1-carboxylic acid, and 1-hydroxynaphthalene-2-carboxylic acid. In the present invention, it is more preferable to use 3,5-di(tert-butyl)-2-hydroxybenzenecarboxylic acid (3,5-di-tert-butylsalicylic acid). By using the aforementioned additive, side reactions are suppressed, and the desired reaction proceeds smoothly, thereby reducing impurities, which are products of side reactions, and shortening the reaction time. The suppression of impurity generation makes it possible to eliminate the purification process, leading to a reduction in manufacturing costs.

[0078] In the present invention, the aromatic oxycarboxylic acid compound is preferably used in an amount of 0.05 to 10 times the molar amount per mole of copper catalyst, more preferably in an amount of 0.1 to 5 times the molar amount, and even more preferably in an amount of 0.2 to 3 times the molar amount.

[0079] <Other additives> In the present invention, sulfite compounds or thiosulfite compounds may be added as needed to prevent the formation of oxides. Examples of sulfite compounds include sodium sulfite, sodium bisulfite, potassium sulfite, potassium bisulfite, magnesium sulfite, cesium sulfite, barium sulfite, and ammonium bisulfite. Examples of thiosulfite compounds include sodium thiosulfite, sodium dithionite, sodium pyrosulfite, ammonium pyrosulfite, and potassium pyrosulfite.

[0080] In the present invention, the amount of sulfite compound or thiosulfate compound is not particularly limited, but it is preferably in the range of 0.01 to 10 moles, and particularly 0.03 to 5 moles, per mole of halogen of the p-diphenyl compound represented by the general formula (6) used as a raw material.

[0081] The Ullmann reaction is generally carried out in a solvent, but it can also be carried out without a solvent. Generally, if the amount of solvent used is small, the reaction system becomes heterogeneous, the amount of unreacted material increases, and the yield may decrease. However, the reaction of the present invention can be carried out without a solvent or with a small amount of solvent after the reaction has started. The reaction solvent is not particularly limited as long as it does not inhibit the reaction, but examples include aliphatic hydrocarbon solvents such as octane, nonane, decane, undecane, dodecane, tridecane, and tetradecane; aromatic hydrocarbon solvents such as toluene, xylene, mesitylene, ethylbenzene, diethylbenzene, diisopropylbenzene, hexylbenzene, octylbenzene, dodecylbenzene, methylnaphthalene, dimethylnaphthalene, 1,2,3,4-tetrahydronaphthalene, and nitrobenzene; ether solvents such as 1,4-dioxane, anisole, and diphenyl ether; amide solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolidinone; and sulfoxide solvents such as dimethyl sulfoxide and tetrahydrothiophene-1,1-dioxide. These may be used individually or in mixtures of two or more types.

[0082] In the present invention, when the reaction is carried out by the Ullmann reaction, the reaction temperature is preferably 190 to 235°C, more preferably 200 to 230°C, and even more preferably 210 to 225°C, from the viewpoint of suppressing impurities due to side reactions.

[0083] In the present invention, the reaction can be carried out under atmospheric pressure or under pressurized conditions, but it is generally preferable to carry it out under stirring in an inert gas atmosphere such as nitrogen or argon. Furthermore, when the reaction is carried out under the above reaction conditions, the reaction time is preferably within the range of 2 to 72 hours from the start of the reaction, and more preferably within the range of 4 to 30 hours.

[0084] The mixture of p-diphenyl compound derivatives of the present invention can be purified by column chromatography, adsorption using silica gel, activated carbon, activated clay, etc., or by crystallization such as recrystallization or reprecipitation with a solvent. Alternatively, it is effective to use a compound with increased purity obtained by using a combination of these methods. Furthermore, the identification of these compounds is performed by synthesizing each compound individually and comparing the retention times (RT) using high-performance liquid chromatography (wavelength 254 nm). The identification of the synthesized compounds is performed by elemental analysis, IR analysis, and NMR analysis. The compounds and mixing ratios of the mixture were determined by high-performance liquid chromatography. The composition ratio (content [%)) of each component in the mixture can be determined from the area ratio of the component peaks obtained at each retention time (HPLC area ratio).

[0085] The mixture of the present invention may contain impurities that are by-products of the reaction. These impurities may be derived from general formula (1), general formula (2), or general formula (3). Examples of such impurities include oxidized forms. Furthermore, a dehalogenated form may be obtained when the halogenated form of the p-diphenyl compound of general formula (6) reacts with one of the diphenylamine compounds represented by general formula (4) or general formula (5) during the reaction process, and the halogen atom of the other p-diphenyl compound of general formula (6) is removed.

[0086] To improve the electrical properties of organic semiconductor materials, the content of impurities, which are by-products of the reaction, is preferably 0-5% or less, more preferably 0-2% or less, and even more preferably 0-1.2% or less.

[0087] [Measurement of the content of by-products in a mixture] The by-product content in the mixture of the present invention can be calculated from the UV absorption peak area obtained by high-performance liquid chromatography (HPLC), using 254 nm UV light for measuring the UV absorption peak area. Since all of the detected components mentioned above are similar compounds derived from the main product, the p-diphenyl compound derivative of the present invention, there are no decisive differences in their spectroscopic properties, and they are considered to be detectable in a similar manner.

[0088] In this invention, the content [%] of the mixture of the present invention (or HPLC purity) can be calculated from the sum of the peak areas derived from the mixture of the present invention relative to the peak area at UV254nm of the HPLC (hereinafter referred to as the total HPLC area). Similarly, the content of by-product impurities (hereinafter referred to as the impurity content [%]) can be calculated from the sum of the peak areas derived from by-product impurities relative to the total HPLC area. When the mixture of the present invention is used as a charge transport material for organic electronic devices, the impurity content is preferably 0 to 5% or less, more preferably 0 to 2% or less, and even more preferably 0 to 1.2% or less relative to the total HPLC area.

[0089] An increase in the impurity content [%] tends to reduce the effectiveness of improving the drive voltage and luminous efficiency, for example, when used as a charge transport layer in an organic EL element, without improving charge injection performance. In other words, by keeping the impurity content [%] within the above-mentioned range, it is believed that an organic electronic device using the mixture of the present invention as a charge transport material can be obtained that has excellent current efficiency, low initial voltage, and excellent electrical characteristics such as drive life characteristics.

[0090] The present invention is characterized by a mixture containing compounds represented by the general formulas (1), (2), and (3) described above.

[0091] In the mixture of the present invention, the content of the compound represented by the general formula (1), calculated by the HPLC area ratio, is preferably 18 to 30%, more preferably 20 to 29%, and even more preferably 21 to 27%.

[0092] In the mixture of the present invention, the content of the compound represented by the general formula (2) is preferably 20-32%, more preferably 22-30%, and even more preferably 23-29%.

[0093] In the mixture of the present invention, the content of the compound represented by the general formula (3) is preferably 45-55%, more preferably 46-54%, and even more preferably 47-53%.

[0094] [Charge transport material] The mixture of the present invention can be used as a charge transport material. When used as a charge transport material, the mixture of the present invention may be contained alone, or it may contain known organic semiconductor materials in any combination, or it may contain additives or other components.

[0095] As used herein, "charge transport material" means a compound, mixture, or other composition that accepts charge from an electrode and facilitates the transfer of charge. A hole transport material can accept and transport holes from the anode. An electron transport material can accept and transport electrons from the cathode.

[0096] The charge transport material of the present invention is suitable as a charge transport layer in organic electronic devices, and it is preferable to use the charge transport material as a film. During film formation, it is necessary that the material exhibits excellent solubility in the aforementioned organic solvents and processability.

[0097] [Solution Process] The mixture of the present invention has solubility suitable for solution processes. In particular, the mixture of the present invention can be used as a composition in a solution state in a solution process to manufacture organic electronic devices. As used herein, "solution process" refers to a process of easily fabricating a multilayer structure element by coating it with a solution, dispersion, emulsion, or other form (composition) in which charge transport materials, etc., are dissolved in an organic solvent.

[0098] When used in solution processes, there are no particular restrictions on the method of forming the charge transport material film, and it can be formed using known methods. Examples include coating methods such as casting, spin coating, dip coating, blade coating, wire bar coating, and spray coating; printing methods such as inkjet printing, screen printing, offset printing, and letterpress printing; and soft lithography techniques such as microcontact printing.

[0099] In the present invention, the solvents used in film formation are aromatic organic solvents such as benzene, toluene, xylene, mesitylene, tetralin (1,2,3,4-tetrahydronaphthalene), monochlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, and nitrobenzene; alkyl halogenated organic solvents such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, and dichloromethane; nitrile solvents such as benzonitrile and acetonitrile; and tetrahydrofuran, dioxane, and diisopropylethanol. Examples of solvents include, but are not limited to, ether-based solvents such as ether, c-pentyl methyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol monomethyl ether; ester-based solvents such as ethyl acetate and propylene glycol monomethyl ether acetate; and alcohol-based solvents such as methanol, isopropanol, n-butanol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, cyclohexanol, and 2-n-butoxyethanol. Furthermore, one or more of the above solvents may be used, and the solvent to be used can be selected depending on the structure.

[0100] [Evaluation of solubility] The mixture of the present invention tends to have improved solubility in the above-mentioned organic solvents. The solubility of the mixture of the present invention is evaluated by adding the mixture of the present invention to 10 g of an organic solvent such as tetrahydrofuran (THF) or toluene, stirring at room temperature (25±5℃) for 3 to 5 minutes, and then visually assessing the solubility (or saturated solubility).

[0101] The solubility of the mixture of the present invention is preferably 20% (weight / weight) or more, more preferably 40% (weight / weight) or more, and even more preferably 50% (weight / weight) or more, since it is necessary to have the solubility required for the industrial operation of the solution process.

[0102] [Assessment of mobility] Mobility is a quantity that indicates the ease with which electrons or holes can be transferred in a solid material when the mixture of the present invention is used as a charge transport material in an organic electronic device. Mobility μ(cm) 2 The coefficient of mobility ( / V·s) is obtained by dividing the average velocity v of the charge by the electric field strength E, and can be considered a proportionality constant when a charge is accelerated in the presence of an electric field. In semiconductors, mobility is inversely proportional to resistivity, so mobility is an important parameter that determines the electrical properties of a material.

[0103] The Time-of-Flight (TOF) method, a common technique for determining the drift mobility of charge in bulk, focuses on the fact that mobility is the proportionality constant when a charge is accelerated in the presence of an electric field, and measures the average velocity v of the charge. Given the sample thickness d and voltage V, the time t required for the charge to pass through the sample is... T By measuring the transient time (or transit time), the average velocity v of the charge can be obtained, and by dividing the obtained average velocity v by the electric field strength E, the carrier mobility μ can be calculated. First, a constant electric field (E=V / L[V / cm]) is applied to the distance between electrodes (d[cm]), and photocarriers are injected by irradiating the vicinity of one electrode with pulsed light. As a result, only carriers of the same polarity as the electric field applied to the electrode travel toward the opposite electrode, and the travel time ([sec]) between these electrodes is measured. The change in current over time is represented on a log-log graph, and the transit time (t) is determined based on the change in its slope. T The time [sec] was calculated. The drift mobility (μ) is calculated using the following formula (a-1).

[0104]

number

[0105] [Organic Electronic Devices] Next, the organic electronic device of the present invention will be described. The organic electronic device of the present invention is characterized by being formed using the charge transport material of the present invention as described above. There are no particular restrictions on the type of organic electronic device as long as the charge transport material of the present invention can be applied. Examples include organic EL elements, organic thin-film transistors (field-effect transistors (FETs), etc.), and photoelectric conversion elements used in light sensors and solar cells.

[0106] It is known that organic electronic devices may have other layers. Furthermore, organic electronic devices can be fabricated by sequentially depositing individual layers onto a suitable substrate using methods such as solution processes. Examples of substrates include inorganic substrates such as glass and plastic substrates made of polymers. Specifically, examples include polyester, polycarbonate, polyimide, polyethersulfone, amorphous polyolefin, epoxy resin, polyamide, polybenzoxazole, and polybenzothiazole. They can also be fabricated by a combination of deposition and coating of individual layers.

[0107] The charge transport material of the present invention can be used on its own, but it can also be used in mixtures with other materials, and furthermore, it can be used in a laminated structure with other layers.

[0108] [Organic EL element] One embodiment of an organic electronic device using the mixture of the present invention is, for example, an organic EL element. In contrast to known compounds such as N,N'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine (hereinafter referred to as NPD) and 4,4'-bis[N-(3-methylphenyl)-N-phenylamino]biphenyl (hereinafter referred to as TPD), which are commonly used as hole transport materials in the manufacture of organic EL devices using a vapor deposition process, the mixture of the present invention exhibits high solubility in solvents commonly used in solution processes.

[0109] The basic structure of the organic EL element of the present invention consists of an anode (transparent electrode), a photoactive layer, and a cathode (counter electrode).

[0110] The present invention provides an organic EL element comprising at least one layer containing the mixture of the present invention or a composition containing the mixture in a photoactive layer. The mixture of the present invention can exist as a single layer or multiple layers in the photoactive layer placed between the anode (transparent electrode) and cathode electrodes, and can be used in particular as a charge transport layer, a hole transport layer, or a light-emitting layer, but is not limited to these. Other layers can be manufactured from any known material.

[0111] The anode (transparent electrode) is an electrode particularly efficient for injecting holes. For example, it can be manufactured from conductive materials containing metals, mixed metals, alloys, metal oxides or mixed metal oxides, conductive polymers, or combinations or mixtures thereof. When transparency is required, specific examples of conductive materials include conductive transparent oxide semiconductors such as tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), and indium-tin composite oxides.

[0112] In addition to the mixture of the present invention, other known materials can be used as the light-emitting layer in the photoactive layer. These include metal complexes of quinolinol derivatives such as tris(8-hydroxyquinolato)aluminum (hereinafter referred to as Alq3), various other metal complexes, anthracene derivatives, bis-styrylbenzene derivatives, pyrene derivatives, oxazole derivatives, and poly(p-phenylenevinylene) derivatives. Furthermore, the light-emitting layer may be composed of a host material and a dopant material. As the host material, in addition to the aforementioned light-emitting materials, thiazole derivatives, benzimidazole derivatives, and polydialkylfluorene derivatives can be used. As the dopant material, quinacridone, coumarin, rubrene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, and aminostyryl derivatives can be used. These materials can be used to form thin films by known methods such as vapor deposition, spin coating, and inkjet printing.

[0113] Organic EL elements can have structures consisting of an anode, hole transport layer, electron blocking layer, light-emitting layer, electron transport layer, and cathode arranged sequentially on a substrate. Other structures include those with a hole injection layer between the anode and the hole transport layer, those with an electron injection layer between the electron transport layer and the cathode, and those with a hole blocking layer between the light-emitting layer and the electron transport layer. In these multilayer structures, it is possible to omit some organic layers. For example, a configuration can have an anode, hole transport layer, light-emitting layer, electron transport layer, and cathode arranged sequentially on a substrate.

[0114] In organic light-emitting diodes (OLEDs), light emission is obtained when charges injected from both electrodes recombine in the light-emitting layer. The key to success lies in efficiently transferring both holes and electrons to the light-emitting layer, and the role of charge transport materials is crucial. For example, in hole transport layers, improving hole injection and electron blocking properties increases the probability of hole and electron recombination, thereby achieving high luminescence efficiency.

[0115] In addition to the mixture of the present invention, N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (hereinafter abbreviated as TPD) and N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine (hereinafter abbreviated as NPD) can be used as the hole transport layer of the organic EL device. Furthermore, as the hole injection and transport layer, a coated polymer material such as poly(3,4-ethylenedioxythiophene) (hereinafter abbreviated as PEDOT) / poly(styrene sulfonate) (hereinafter abbreviated as PSS) can be used.

[0116] As hole-blocking layers for organic EL devices, metal complexes of phenanthroline derivatives such as bathocuproine and quinolinol derivatives such as aluminum(III) bis(2-methyl-8-quinolinate)-4-phenylphenolate (hereinafter abbreviated as BAlq), as well as various rare earth complexes, triazole derivatives, triazine derivatives, oxadiazole derivatives, and other compounds can be used. These materials may also serve as materials for the electron transport layer.

[0117] As electron transport layers for organic EL devices, metal complexes of quinolinol derivatives such as Alq3 and BAlq, as well as various other metal complexes, triazole derivatives, triazine derivatives, oxadiazole derivatives, thiadiazole derivatives, carbodiimide derivatives, quinoxaline derivatives, and the like can be used.

[0118] For the electron injection layer of an organic EL element, alkali metal salts such as lithium fluoride and cesium fluoride, alkaline earth metal salts such as magnesium fluoride, and metal oxides such as aluminum oxide can be used, but this can also be omitted.

[0119] For the cathode (counter electrode) of an organic EL element, specific materials used include metals such as platinum, titanium, stainless steel, aluminum, gold, silver, and nickel, or alloys thereof. Electrode materials with low work functions, such as aluminum, and alloys with even lower work functions, such as magnesium-silver alloys, magnesium-indium alloys, and aluminum-magnesium alloys, are used as electrode materials.

[0120] Examples of other organic electronic devices having at least one layer of the mixture of the present invention or a composition containing the mixture include, but are not limited to, solar cells and photosensors having photoelectric conversion elements.

[0121] [Photoelectric conversion element] One embodiment of an organic electronic device using the mixture of the present invention is, for example, a photoelectric conversion element. The basic structure of the photoelectric conversion element of the present invention consists of a transparent electrode (conductive support), a photoelectric conversion unit, and a counter electrode.

[0122] The structure of the photoelectric conversion element preferably comprises, in order on a substrate, a conductive support, a hole blocking layer, an electron transport layer, a photoelectric conversion layer, a hole transport layer, and a counter electrode, but is not limited to this. Alternatively, it may be configured in the order of a conductive support, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a counter electrode.

[0123] The conductive support and counter electrodes of the photoelectric conversion element can be made from the same materials as those described for the anode and cathode of the organic EL element.

[0124] Specific examples of semiconductors that form electron transport layers include metal oxides such as tin oxide (SnO, SnO2, SnO3, etc.), titanium oxide (TiO2, etc.), tungsten oxide (WO2, WO3, W2O3, etc.), zinc oxide (ZnO), niobium oxide (Nb2O5, etc.), tantalum oxide (Ta2O5, etc.), yttrium oxide (Y2O3, etc.), and strontium titanate (SrTiO3, etc.); metal sulfides such as titanium sulfide, zinc sulfide, zirconium sulfide, copper sulfide, tin sulfide, indium sulfide, and tungsten sulfide; metal selenides such as titanium selenide, zirconium selenide, and indium selenide; and elemental semiconductors such as silicon. The electron transport layer can be obtained using known film-forming methods depending on the material being formed. Any coating method using a coating solution can be used to form the electron transport layer.

[0125] For example, when used as a perovskite-type photoelectric conversion element, the perovskite material that constitutes the photoelectric conversion layer may include, but is not limited to, a layer containing a perovskite material of mixed cations and mixed anions represented by any composition such as methylammonium PbI3, formiamidinium PbI3, ethylammonium PbI3, and CsPbI3. It is preferable to use one or more of these perovskite materials, and they may also contain light absorbers other than the perovskite material.

[0126] The mixture of the present invention is useful as a charge transport material for photoelectric conversion elements, etc. In particular, when used as a hole transport material, it is possible to efficiently extract current, and a highly efficient and highly durable photoelectric conversion element can be obtained.

[0127] When used as a hole transport layer in a photoelectric conversion element, additives may be included to further improve the hole transport characteristics. The hole transport layer may contain dopants (or oxidizing agents) or basic compounds (or basic additives) as additives. Including additives in the hole transport layer to increase the carrier concentration of the hole transport material in the hole transport layer (doping) leads to improved conversion efficiency of the photoelectric conversion element.

[0128] The photoelectric conversion element using the charge transport material of the present invention can be applied to dye-sensitized solar cells, perovskite solar cells, organic thin-film solar cells, and various photosensors. When used as a solar cell, the photoelectric conversion element containing the mixture of the present invention becomes a cell, and the required number of these cells are arranged to form a module, which is then provided with predetermined electrical wiring.

[0129] [Organic thin-film transistor (field-effect transistor)] As one embodiment of the organic electronic device of the present invention, a field-effect transistor (FET), which is a type of switching element, will be described as an example. The basic structure of a field-effect transistor is that it has an insulating layer, a gate electrode and a charge transport layer isolated by the insulating layer, and a source electrode and a drain electrode provided in contact with the charge transport layer, on a support substrate. The order in which the layers are stacked is not particularly limited, and they may be stacked in any order.

[0130] The charge transport material of the present invention is suitable for use as a charge transport layer when formed into a film on a substrate or the like. The thickness of the charge transport film is not particularly limited. In the case of the field-effect transistor exemplified above, the characteristics of the device do not depend on the film thickness as long as it is above the required thickness. Therefore, a preferred film thickness is usually 1 nm or more, preferably 10 nm or more. Also, a thickness of 10 μm or less is usually preferable, and 500 nm or less is particularly desirable.

[0131] The organic thin-film transistor using the charge transport material of the present invention can be used as a switching element in the active matrix of a display. This utilizes the fact that the current between the source and drain can be switched by the voltage applied to the gate, so that the switch is turned on only when a voltage is applied or current is supplied to a certain display element, and the circuit is disconnected at other times, thereby enabling high-speed, high-contrast displays. It is expected to be an element that can be manufactured using energy-saving and low-cost processes.

[0132] Although preferred embodiments have been described above, the present invention is not limited thereto, and may be modified as appropriate without departing from the scope of the present invention. [Examples]

[0133] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. The physical properties and identification of the products obtained in the synthesis examples were performed by melting point measurement (Mettler Toledo, model FP-62) or high-performance liquid chromatography (Shimadzu Corporation, model LC-10A). In the examples, parts represent parts by mass.

[0134] [Example 1] (Synthesis of mixture No. 1 containing compound (A-1), compound (A-2), and compound (B-1)) 24.25 g (132 mmol) of 4-methyldiphenylamine, 26.10 g (132 mmol) of 4,4'-dimethyldiphenylamine, 46.7 g (115 mmol) of 4,4'-diiodobiphenyl, 39.75 g (288 mmol) of anhydrous potassium carbonate, 0.7 g (10 mmol) of copper powder, 1.2 g (11 mmol) of sodium bisulfite, 0.7 g (2.8 mmol) of 3,5-di-tert-butylsalicylic acid, and 111 mL of toluene were mixed and heated to 220-225°C with nitrogen gas introduced and stirred for 6 hours. After the reaction was complete, the reaction product was extracted with 288 mL of toluene, insoluble matter was filtered off, and the filtrate was concentrated to dryness. The obtained solid was purified by column chromatography (support: silica gel, eluent: toluene:hexane = 1:4) to obtain 4,4'-bis(4-methyldiphenylamino)-p-diphenyl (compound (A-1)), 4-[di(4-methyldiphenylamino)-p-diphenyl Ruf Enil ) amino ] -4'- (4-methyl diphenylamino)-p-diphenyl(compound( B - 1 )) and 4,4'-bis[di (4-methyl Phenyl ) amino ] -p-diphenyl(compound( A - 2 A mixture of p-diphenyl compound derivatives containing )) No. 1, compound (A-1): compound ( B - 1 ):Compound( A - 2 A mixture ratio of 23.5:49.7:26.8 (peak area ratio by high-performance liquid chromatography) yielded 54.91 g (yield: 88.2%, HPLC purity: 99.3%, melting point: 141-143°C).

[0135] Compound identification was performed by identifying each compound using commercially available or single-component synthetic compounds, and then comparing the retention times using high-performance liquid chromatography (HILM). The HILM conditions for compound identification and measurement of mixing ratios were as follows: Column: ODS column, Eluent: Tetrahydrofuran / methanol = 1 / 10 (v / v), Measurement wavelength: 254 nm.

[0136] <Measuring solubility in organic solvents> At room temperature (25±5℃), mixture No. 1 was placed in a clear sample bottle and added to 10g of tetrahydrofuran (THF) and 10g of toluene. After stirring for 3-5 minutes, solubility was visually confirmed. The results are shown in Table 1. Solubility is expressed in % (weight / weight).

[0137] [Example 2] (Synthesis of mixture No. 2 containing compound (A-1), compound (A-2), and compound (B-1)) 20.4 g (111 mmol) of 4-methyldiphenylamine, 26.8 g (136 mmol) of 4,4'-dimethyldiphenylamine, 43.65 g (107.5 mmol) of 4,4'-diiodobiphenyl, 37.15 g (269 mmol) of anhydrous potassium carbonate, 0.7 g (10 mmol) of copper powder, 1.2 g (11 mmol) of sodium bisulfite, 0.7 g (2.8 mmol) of 3,5-di-tert-butylsalicylic acid, and 111 mL of toluene were mixed and heated to 220-225°C with nitrogen gas introduced and stirred for 6 hours. After the reaction was complete, the reaction product was extracted with 150 mL of toluene, insoluble matter was filtered off, and the filtrate was concentrated to dryness. The obtained solid was purified by column chromatography (support: silica gel, eluent: toluene:hexane = 1:4) to obtain 4,4'-bis(4-methyldiphenylamino)-p-diphenyl (compound (A-1)), 4-[di(4-methyldiphenylamino)-p-diphenyl Ruf Enil ) amino ] -4'- (4-methyl diphenylamino)-p-diphenyl(compound( B - 1 )) and 4,4'-bis[di (4-methyl Phenyl ) amino ] -p-diphenyl(compound( A - 2 A mixture of p-diphenyl compound derivatives containing )) No. 2, compound (A-1): compound ( B - 1 ):Compound( A - 2 52.95 g (yield: 92.8%, HPLC purity: 99.0%, melting point: 167-173°C) was obtained with a mixing ratio of ) = 18.8:48.4:31.8 (peak area ratio by high-performance liquid chromatography).

[0138] Compound identification was performed in the same manner as in Example 1.

[0139] <Measuring solubility in organic solvents> Solubility measurements were performed in the same manner as in Example 1, except that mixture No. 2 was used instead. The results are shown in Table 1.

[0140] [Example 3] (Synthesis of mixture No. 3 containing compound (A-1), compound (A-2), and compound (B-1)) 24.9 g (136 mmol) of 4-methyldiphenylamine, 29.5 g (111 mmol) of 4,4'-dimethyldiphenylamine, 43.65 g (107.5 mmol) of 4,4'-diiodobiphenyl, 37.15 g (269 mmol) of anhydrous potassium carbonate, 0.7 g (10 mmol) of copper powder, 1.2 g (11 mmol) of sodium bisulfite, 0.7 g (2.8 mmol) of 3,5-di-tert-butylsalicylic acid, and 111 mL of toluene were mixed and heated to 220-225°C while introducing nitrogen gas, and stirred for 6 hours. After the reaction was complete, the reaction product was extracted with 150 mL of toluene, insoluble matter was filtered off, and the filtrate was concentrated to dryness. The obtained solid was purified by column chromatography (support: silica gel, eluent: toluene:hexane = 1:4) to obtain 4,4'-bis(4-methyldiphenylamino)-p-diphenyl (compound (A-1)), 4-[di(4-methyldiphenylamino)-p-diphenyl Ruf Enil ) amino ] -4'- (4-methyl diphenylamino)-p-diphenyl(compound( B - 1 )) and 4,4'-bis[di (4-methyl Phenyl ) amino ] -p-diphenyl(compound( A - 2 A mixture of p-diphenyl compound derivatives containing )) No. 3, compound (A-1): compound ( B - 1 ):Compound( A - 2 52.25 g was obtained (yield: 92.9%, HPLC purity: 99.2%, melting point: 140-142°C) with a mixing ratio of 28.4:49.2:21.6 (peak area ratio by high-performance liquid chromatography).

[0141] Compound identification was performed in the same manner as in Example 1.

[0142] <Measuring solubility in organic solvents> Solubility measurements were performed in the same manner as in Example 1, except that mixture No. 3 was used instead. The results are shown in Table 1.

[0143] [Comparative Example 1] Solubility in organic solvents The solubility was measured in the same manner as in Example 1, except that mixture No. 1 in Example 1 was replaced with the comparative compound represented by (C-1) below (HCT-306, manufactured by Hodogaya Chemical Co., Ltd.). The results are shown in Table 1.

[0144] [ka]

[0145] [Comparative Examples 2 and 3] Solubility in organic solvents The solubility was measured in the same manner as in Example 1, except that mixture No. 1 in Example 1 was replaced with either the comparative compound represented by (A-1) below (HCT-308, manufactured by Hodogaya Chemical Co., Ltd.) or the comparative compound represented by (A-2) below (MPCT-61, manufactured by Mitsubishi Paper Mills Ltd.). The results are shown in Table 1.

[0146] [ka]

[0147] [ka]

[0148] [Table 1]

[0149] When comparing the solubility of the mixture of the present invention with that of a comparative compound, it was confirmed that the mixture of the present invention exhibits superior solubility, showing 3 to 7 times the solubility of the comparative compound.

[0150] [Example 4] Mixture No. 1 (1.0 part) obtained in Example 1 was added to 12.2% tetrahydrofuran in polycarbonate resin (Yupilon Z, manufactured by Mitsubishi Engineering Plastics Corporation) and dissolved by sonication. This solution was applied to the aluminum surface of an aluminum-deposited PET film, which served as a conductive support, using a wire bar, and dried at 110°C under normal pressure for 30 minutes to form a film with a thickness of 10 μm. A translucent gold electrode was then deposited on the film. With a voltage applied between the conductive support and the translucent electrode of the measurement sample, the thin film was irradiated with a dye laser with a pulse width of 3 nsec and a center wavelength of 610 nm via the translucent gold electrode. The drift mobility of the obtained element was measured by the Time-of-flight method, with an electric field strength of 2 × 10⁻⁶. 5 Measurements were taken in (V / cm). The results are shown in Table 2.

[0151] [Comparative Example 4] Except for using the compound represented by (A-7) below (HCT-305N, manufactured by Hodogaya Chemical Co., Ltd.) as a comparative compound, the device was fabricated in the same manner as in Example 4, and the drift mobility was measured. The results are shown in Table 2.

[0152] [ka]

[0153] [Table 2]

[0154] Tables 1 and 2 show that the mixture of p-diphenyl compound derivatives of the present invention has higher solubility in organic solvents and superior drift mobility compared to conventional products. [Industrial applicability]

[0155] The mixture of p-diphenyl compound derivatives of the present invention exhibits significantly improved solubility in organic solvents and superior mobility compared to conventional products, resulting in excellent properties for organic semiconductor materials. Therefore, it is useful as a charge transport material that can be applied to organic electronic devices such as photoelectric conversion elements like solar cells and light sensors, organic EL elements, and organic thin-film transistors.

Claims

1. The following general formulas (1), (2), and (3) represent p-diphenyl compound derivatives, A mixture in which the content of the compound represented by the general formula (1) is 18 to 30%, the content of the compound represented by the general formula (2) is 20 to 32%, and the content of the compound represented by the general formula (3) is 45 to 55%. 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 [In the formula, R1 represents a linear or branched alkyl group having 1 to 20 carbon atoms, which may have substituents; R3 represents a hydrogen atom; R5 and R7 each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms, which may have substituents; and R2, R4, R6, and R8 each independently represent a hydrogen atom.]

2. The compound represented by the general formula (1) is the compound represented by the following general formula (A-1), The compound represented by the general formula (2) is the compound represented by the following general formula (A-2), The mixture according to claim 1, wherein the compound represented by the general formula (3) is the compound represented by the following general formula (B-1). 【Chemistry 4】

3. The mixture according to claim 1 or 2, wherein the solubility at room temperature (25±5℃) per 10 g of organic solvent is 50% by weight or more.

4. A method for producing a mixture containing the p-diphenyl compound derivatives represented by the general formulas (1), (2), and (3) described in claim 1, A method for producing a mixture obtained by a one-step reaction from compounds represented by the following general formulas (4), (5), and (6). 【Transformation 5】 【Transformation 6】 【Transformation 7】 [In the formula, X represents a halogen atom.]

5. The method for producing the mixture according to claims 7 and 4, wherein the aforementioned one-step reaction is an Ullmann reaction and the reaction temperature is 190 to 235°C.

6. The method for producing the mixture according to claim 5, characterized in that the additive for the Ullmann reaction is an aromatic oxycarboxylic acid compound.

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