Fluorene derivatives and their uses

Abstract

Provide a fluorene derivative represented by the following formula (1). (In the formula, Z 1 and Z 2 are defined divalent groups, Ar 1 and Ar 2 are each independently an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, and may be substituted by a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a bicycloalkyl group having 4 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Ar 3 and Ar 4 are each independently a defined aromatic ring-containing group.)

Description

Technical Field

[0001] The present invention relates to fluorene derivatives and their uses. Background Art

[0002] In an organic electroluminescence (EL) element, a charge-transporting thin film containing an organic compound is used as a light-emitting layer and a charge injection layer. In particular, the hole injection layer is responsible for the transfer of charges between the anode and the hole transport layer or the light-emitting layer, and plays an important role in achieving low-voltage driving and high brightness of the organic EL element.

[0003] So far, various studies have been conducted to improve the performance of organic EL elements. For the purpose of improving the light extraction efficiency, etc., studies have been carried out on adjusting the refractive index of the functional films used. Specifically, considering the overall structure of the element and the refractive index of other adjacent components, attempts have been made to achieve high efficiency of the element by using a hole injection layer and a hole transport layer with a higher or lower refractive index (Patent Documents 1 and 2). Therefore, the refractive index is an important element in the design of organic EL elements, and for materials for organic EL elements, the refractive index is also considered to be an important physical property value.

[0004] In addition, regarding the coloring of the charge-transporting thin film for organic EL elements, in view of the actual situations such as reducing the color purity and color reproducibility of organic EL elements, in recent years, it has been desired that the charge-transporting thin film for organic EL elements has a high transmittance (transmission rate) in the visible region and has high transparency (see Patent Document 3).

[0005] The formation methods of the hole injection layer are roughly divided into a dry method represented by evaporation and a wet method represented by spin coating. If these methods are compared, the wet method can efficiently manufacture a film with high flatness over a large area. Therefore, with the ongoing large-area development of organic EL displays, there is often a need for wet-process materials that can be formed by the wet method and provide charge-transporting thin films with excellent refractive index and transparency.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-536718

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-501585

[0010] Patent Document 3: International Publication No. 2013 / 042623 Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] The present invention has been completed in view of the above actual situation, and an object thereof is to provide a compound which provides a film having good charge transport properties, a high refractive index, and high transparency by low-temperature firing, and an organic EL element having excellent characteristics can be realized when the film is applied to a hole injection layer or the like.

[0013] Means for Solving the Problem

[0014] The inventors of the present invention conducted intensive studies repeatedly to achieve the above object, and as a result, found that: a film obtained using a specific fluorene derivative exhibits high charge transport properties, and is a film having high transparency and a high refractive index, and an organic EL element having excellent characteristics can be obtained when the film is applied to a hole injection layer or the like, and thus completed the present invention.

[0015] That is, the present invention provides the following fluorene derivative and its use.

[0016] 1. A fluorene derivative represented by the following formula (1).

[0017] [Chemical Formula 1]

[0018]

[0019] [In the formula, Z 1 and Z 2 each independently represents a group represented by any one of the following formulas (2) to (7);

[0020] [Chemical Formula 2]

[0021]

[0022] (In the formula, the dashed line is a bonding end. R A and R B each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.)

[0023] Ar 1 and Ar 2 each independently represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, and may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a bicycloalkyl group having 4 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms;

[0024] Ar 3 and Ar 4 each independently represents a group represented by any one of the following formulas (8) to (11).

[0025] [Chemical Formula 3]

[0026]

[0027] (In the formula, the dotted line represents the bonding end,

[0028] R 1 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms which may be substituted by a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms or a halogenated alkyl group having 1 to 20 carbon atoms, a heteroaryl group having 6 to 20 carbon atoms which may be substituted by an alkyl group having 1 to 20 carbon atoms or a halogenated alkyl group having 1 to 20 carbon atoms, or a group represented by any one of the following formulas (12) to (14),

[0029] R 2 to R 52 are each independently a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms or a halogenated alkyl group having 1 to 20 carbon atoms.

[0030] [Chemical formula 4]

[0031]

[0032] (In the formula, the dotted line represents the bonding end,

[0033] D A is a diarylamino group in which each aryl group is independently an aryl group having 6 to 20 carbon atoms,

[0034] R 53 to R 76 are each independently a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms or a halogenated alkyl group having 1 to 20 carbon atoms.))]

[0035] The fluorene derivative of 2.1, wherein Ar 1 and Ar 2 are each independently a phenyl group, a 1-naphthyl group or a 2-naphthyl group, or a group represented by the following formulas (T1-1) to (T11-4), formulas (F1-1) to (F4-4), formulas (N1-1) to (N10-7) or formulas (M1-1) to (M4-3).

[0036] [Chemical formula 5]

[0037]

[0038] (In the formula, the dotted line represents the bonding end.)

[0039] [Chemical formula 6]

[0040]

[0041] (In the formula, the dotted line represents the bonding end.)

[0042] [Chemical formula 7]

[0043]

[0044] (In the formula, the dashed line represents the bonding end.)

[0045] [Chemical formula 8]

[0046]

[0047] (In the formula, the dashed line represents the bonding end.)

[0048] [Chemical formula 9]

[0049]

[0050] (In the formula, the dashed line represents the bonding end.)

[0051] [Chemical formula 10]

[0052]

[0053] (In the formula, the dashed line represents the bonding end.)

[0054] 3. A fluorene derivative of 1 or 2, wherein Ar 1 and Ar 2 are the same group.

[0055] 4. A fluorene derivative according to any one of 1 to 3, wherein Z 1 and Z 2 are groups represented by formula (2).

[0056] 5. A fluorene derivative according to any one of 1 to 4, wherein R 1 is a phenyl group.

[0057] 6. A fluorene derivative according to any one of 1 to 5, wherein R 2 to R 76 are hydrogen atoms.

[0058] 7. A charge transporting material comprising a fluorene derivative according to any one of 1 to 6.

[0059] 8. A charge transporting varnish comprising the charge transporting material of 7 and an organic solvent.

[0060] 9. The charge transporting varnish of 8, which further comprises a dopant.

[0061] 10. A charge transporting film obtained from the charge transporting varnish of 8 or 9.

[0062] 11. An organic EL element comprising the charge transporting film of 10.

[0063] 12. A method for producing a fluorene derivative represented by the following formula (1), which comprises:

[0064] A step of reacting the compound represented by formula (15) with the compound represented by formula (16-1) and the compound represented by formula (16-2) to obtain an intermediate represented by formula (17);

[0065] A step of reducing the intermediate represented by formula (17) to obtain an intermediate represented by formula (18); and

[0066] A step of reacting the intermediate represented by formula (18) with the halide represented by formula (19-1) and the halide represented by formula (19-2).

[0067] [Chemical formula 11]

[0068]

[0069] (In the formula, Z 1 , Z 2 , Ar 1 , Ar 2 , Ar 3 and Ar 4 are the same as above; X is a halogen atom or a pseudohalogen group.)

[0070] Advantages of the Invention

[0071] By using the charge transporting varnish containing the fluorene derivative of the present invention, a film with high transparency and high refractive index can be produced. In addition, a film with excellent charge transporting properties can be obtained even when fired at a low temperature of 200 °C or lower. The charge transporting film obtained from the charge transporting varnish of the present invention can be suitably used as a film for electronic components represented by organic EL elements. By using it as a hole injection layer, a hole transporting layer, particularly a hole injection layer, of an organic EL element, an organic EL element with excellent characteristics can be obtained. Detailed Description of the Invention

[0072] [Fluorene Derivative]

[0073] The fluorene derivative of the present invention is represented by the following formula (1).

[0074] [Chemical formula 12]

[0075]

[0076] As the compound represented by formula (1), the following compounds can be mentioned, but are not limited thereto.

[0077] [Chemical formula 13]

[0078]

[0079] In formula (1), Z 1 and Z2 Each independently represents a group represented by any one of the following formulas (2) to (7). Further, in Z 1 and Z 2 when it is a group represented by formula (4) or (5), the carbon atom contained in the group is bonded to the nitrogen atom in formula (1).

[0080] [Chemical formula 14]

[0081]

[0082] In formulas (2) to (7), the dashed line is the bonding end. In formula (6), R A and R B each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, preferably a hydrogen atom.

[0083] Regarding the alkyl group having 1 to 20 carbon atoms represented by R A and R B it may be linear, branched or cyclic. Specific examples thereof include linear or branched alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl; cyclic alkyl groups having 3 to 20 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclobutyl, bicyclopentyl, bicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl, bicyclodecyl.

[0084] As Z 1 and Z 2 preferably represents a group represented by formula (2), (3), (4), (5) or (6), more preferably a group represented by formula (2), (4) or (6), and still more preferably a group represented by formula (2).

[0085] In formula (1), Ar 1 and Ar 2 each independently represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms.

[0086] As the aryl group having 6 to 20 carbon atoms represented by Ar 1 and Ar 2 phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, etc. can be cited.

[0087] As the Ar 1 and Ar 2The heteroaryl groups having 2 to 20 carbon atoms represented include groups represented by the following formulas (T1-1) to (T11-4), formulas (F1-1) to (F4-4), formulas (N1-1) to (N10-7), and formulas (M1-1) to (M4-3), etc., but are not limited thereto. Among them, from the viewpoint of achieving a higher refractive index, as the above heteroaryl group, a sulfur-containing heteroaryl group or a nitrogen-containing heteroaryl group is preferred, and a sulfur-containing heteroaryl group is more preferred.

[0088] [Chemical formula 15]

[0089]

[0090] (In the formula, the dashed line is the bonding end.)

[0091] [Chemical formula 16]

[0092]

[0093] (In the formula, the dashed line is the bonding end.)

[0094] [Chemical formula 17]

[0095]

[0096] (In the formula, the dashed line is the bonding end.)

[0097] [Chemical formula 18]

[0098]

[0099] (In the formula, the dashed line is the bonding end.)

[0100] [Chemical formula 19]

[0101]

[0102] (In the formula, the dashed line is the bonding end.)

[0103] [Chemical formula 20]

[0104]

[0105] (In the formula, the dashed line is the bonding end.)

[0106] The aryl group having 6 to 20 carbon atoms or the heteroaryl group having 2 to 20 carbon atoms represented by Ar 1 and Ar 2 may be substituted by a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

[0107] Regarding the above alkyl groups having 1 to 20 carbon atoms, they can be linear, branched or cyclic. As specific examples thereof, groups similar to those described in the explanations of R A and R B can be cited.

[0108] Regarding the above alkenyl groups having 2 to 20 carbon atoms, they can be linear, branched or cyclic. As specific examples thereof, vinyl, n-1-propenyl, n-2-propenyl, 1-methylethenyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentenyl, n-1-decenyl, n-1-icosene, etc. can be cited.

[0109] Regarding the above alkynyl groups having 2 to 20 carbon atoms, they can be linear, branched or cyclic. As specific examples thereof, ethynyl, n-1-propynyl, n-2-propynyl, n-1-butynyl, n-2-butynyl, n-3-butynyl, 1-methyl-2-propynyl, n-1-pentynyl, n-2-pentynyl, n-3-pentynyl, n-4-pentynyl, 1-methyl-n-butynyl, 2-methyl-n-butynyl, 3-methyl-n-butynyl, 1,1-dimethyl-n-propynyl, n-1-hexynyl, n-1-decynyl, n-1-pentadecynyl, n-1-icosynyl, etc. can be cited.

[0110] Regarding the above alkoxy groups having 1 to 20 carbon atoms, they can be linear, branched or cyclic. As specific examples thereof, linear or branched alkoxy groups having 1 to 20 carbon atoms such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, etc.; cyclic alkoxy groups having 3 to 20 carbon atoms such as cyclopropoxy, cyclobutoxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, cyclooctyloxy, cyclononyloxy, cyclodecyloxy, bicyclobutoxy, bicyclopentyloxy, bicyclohexyloxy, bicycloheptyloxy, bicyclooctyloxy, bicyclononyloxy, bicyclodecyloxy, etc. can be cited.

[0111] Among these, as Ar 1 and Ar 2, preferably phenyl; nitrophenyl; alkylphenyl such as methylphenyl, ethylphenyl, propylphenyl, dimethylphenyl, diethylphenyl, dipropylphenyl, trimethylphenyl, triethylphenyl, tripropylphenyl, and structural isomers thereof; alkenylphenyl such as vinylphenyl, 1-propenylphenyl, 2-propenylphenyl; alkynylphenyl such as ethynylphenyl, 1-propynylphenyl, 2-propynylphenyl; 1-naphthyl; nitro-1-naphthyl; alkyl-1-naphthyl such as methyl-1-naphthyl, ethyl-1-naphthyl, propyl-1-naphthyl, dimethyl-1-naphthyl, diethyl-1-naphthyl, dipropyl-1-naphthyl, trimethyl-1-naphthyl, triethyl-1-naphthyl, tripropyl-1-naphthyl, and structural isomers thereof; alkenyl-1-naphthyl such as vinyl-1-naphthyl, 1-propenyl-1-naphthyl, 2-propenyl-1-naphthyl; alkynyl-1-naphthyl such as ethynyl-1-naphthyl, 1-propynyl-1-naphthyl, 2-propynyl-1-naphthyl; 2-naphthyl; nitro-2-naphthyl; alkyl-2-naphthyl such as methyl-2-naphthyl, ethyl-2-naphthyl, propyl-2-naphthyl, dimethyl-2-naphthyl, diethyl-2-naphthyl, dipropyl-2-naphthyl, trimethyl-2-naphthyl, triethyl-2-naphthyl, tripropyl-2-naphthyl, and structural isomers thereof; alkenyl-2-naphthyl such as vinyl-2-naphthyl, 1-propenyl-2-naphthyl, 2-propenyl-2-naphthyl; alkynyl-2-naphthyl such as ethynyl-2-naphthyl, 1-propynyl-2-naphthyl, 2-propynyl-2-naphthyl; 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 9-phenanthryl; groups represented by the formulas (T1-1) to (T11-4), etc. In addition, from the viewpoint of the ease of synthesis of the above fluorene derivatives, Ar 1 and Ar 2 are preferably the same group.

[0112] In formula (1), Ar 3 and Ar 4 each independently represent a group represented by any one of the following formulas (8) to (11).

[0113] [Chemical formula 21]

[0114]

[0115] In formulas (8) to (11), the dashed line is a bonding end. In formula (8), R 1 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms which may be substituted by a cyano group, a nitro group, a halogen atom, an alkyl group having 1 to 20 carbon atoms or a haloalkyl group having 1 to 20 carbon atoms, or a heteroaryl group having 6 to 20 carbon atoms which may be substituted by an alkyl group having 1 to 20 carbon atoms or a haloalkyl group having 1 to 20 carbon atoms, or a group represented by any one of the following formulas (12) to (14).

[0116] [Chemical formula 22]

[0117]

[0118] In formulas (12) to (14), the dashed line represents a bonding end. D A is a diarylamino in which each aryl group is independently an aryl group having 6 to 20 carbon atoms.

[0119] As the alkyl group having 1 to 20 carbon atoms represented by R 1 and the alkyl group having 1 to 20 carbon atoms as the above-mentioned substituent, groups the same as those described in the explanations of R A and R B can be cited. As the aryl group having 6 to 20 carbon atoms represented by R 1 , groups the same as those described in the explanations of Ar 1 and Ar 2 in formula (1) can be cited. As the heteroaryl group having 2 to 20 carbon atoms represented by R 1 , 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 2-imidazolyl, 4-imidazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, etc. can be cited.

[0120] As the above-mentioned halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. can be cited. As the above-mentioned haloalkyl group having 1 to 20 carbon atoms, a group in which a part or all of the hydrogen atoms of the above-mentioned alkyl group having 1 to 20 carbon atoms are substituted with the above-mentioned halogen atom can be cited. Specifically, groups the same as those described later in the explanation of formula (B) can be cited. As the above-mentioned diarylamino, diphenylamino, dinaphthylamino, dianthrylamino, N-phenyl-N-naphthylamino, N-phenyl-N-anthrylamino, N-naphthyl-N-anthrylamino, etc. can be cited.

[0121] As the group represented by formulas (12) to (14), those represented by the following formulas (12-1) to (14-1) etc. are preferred.

[0122] [Chemical formula 23]

[0123]

[0124] Among these, as R 1, preferably a hydrogen atom, phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, a group represented by formula (12-1), a group represented by formula (13-1), etc., more preferably a group represented by formula (12-1), a group represented by formula (13-1), phenyl group, and further preferably phenyl group.

[0125] In formulas (8) to (14), R 2 ~R 76 are each independently a hydrogen atom, cyano group, nitro group, halogen atom, alkyl group having 1 to 20 carbon atoms or haloalkyl group having 1 to 20 carbon atoms. As the alkyl group having 1 to 20 carbon atoms represented by R 2 ~R 76 , groups the same as those described in the explanations of R A and R B in formula (6) can be cited. Among these, as R 2 ~R 76 , preferably a hydrogen atom, cyano group, nitro group, halogen atom, alkyl group having 1 to 10 carbon atoms or haloalkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom, cyano group, nitro group, halogen atom, trifluoromethyl group, and further preferably all are hydrogen atoms.

[0126] As the groups represented by formulas (8) to (11), the following groups can be cited, but are not limited thereto.

[0127] [Chemical formula 24]

[0128]

[0129] (In the formula, R 1 ~R 52 are the same as above. The dashed line is the bonding end.)

[0130] As the groups represented by formulas (8) to (11), the following groups are particularly preferred.

[0131] [Chemical formula 25]

[0132]

[0133] (In the formula, the dashed line is the bonding end.)

[0134] [Synthesis method of fluorene derivative]

[0135] The fluorene derivative of the present invention can be synthesized by the method shown in Scheme A below.

[0136] [Chemical formula 26]

[0137] Scheme A

[0138]

[0139] (wherein, Z 1 , Z 2 , Ar 1 , Ar 2 , Ar 3 and Ar 4 are the same as those above. X is a halogen atom or a pseudo-halogen group.)

[0140] Examples of the above halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. Further, examples of the above pseudo-halogen group include fluoroalkylsulfonyloxy groups such as methanesulfonyloxy, trifluoromethanesulfonyloxy, nonafluorobutanesulfonyloxy; aromatic sulfonyloxy groups such as benzenesulfonyloxy, toluenesulfonyloxy, etc.)

[0141] The compound represented by the formula (15) can be synthesized by a conventionally known method. For example, it can be synthesized according to the method described in J. Mater. Chem. C, 2014, pages 1068 - 1075.)

[0142] In Scheme A, the first step is a step of obtaining an intermediate represented by the formula (17) from the compound represented by the formula (15), the compound represented by the formula (16 - 1), and the compound represented by the formula (16 - 2) by using a coupling reaction. Further, in Scheme A, as an example, a synthesis method using the Suzuki - Miyaura coupling reaction is shown, and other coupling reactions can also be used for synthesis.)

[0143] Examples of the catalyst used in the Suzuki - Miyaura coupling reaction include [1,1'-bis(diphenylphosphino)ferrocene] palladium(II) dichloride (PdCl 2 (dppf)), tetrakis(triphenylphosphine)palladium (Pd(PPh 3 ) 4 ), bis(triphenylphosphine)palladium(II) dichloride (Pd(PPh 3 ) 2 Cl 2 ), bis(benzylideneacetone)palladium (Pd(dba) 2 ), tris(benzylideneacetone)dipalladium (Pd 2 (dba) 3 ), bis(tritert - butylphosphine)palladium (Pd(P - t - Bu 3 ) 2 ), palladium(II) acetate (Pd(OAc) 2 ) and other palladium catalysts. Among these, from the viewpoint of obtaining the target product with high efficiency, preferred catalysts are PdCl 2 (dppf), Pd(PPh 3 ) 4 , Pd(PPh 3 )2 Cl 2 、Pd(P-t-Bu 3 ) 2 , more preferably Pd(PPh 3 ) 4 、Pd(P-t-Bu 3 ) 2 . Regarding the usage amount of the above catalyst, relative to the compound represented by the formula (15), it is usually about 0.1 to 50 mol%, preferably 0.1 to 30 mol%, and more preferably 1 to 10 mol%.

[0144] In addition, a base is also used in the Suzuki-Miyaura coupling reaction. As the above base, hydroxides such as sodium hydroxide, potassium hydroxide, cesium hydroxide, etc., alkoxides such as sodium tert-butoxide, potassium tert-butoxide, etc.; fluoride salts such as lithium fluoride, potassium fluoride, cesium fluoride, etc.; carbonate salts such as lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, potassium bicarbonate, etc.; phosphate salts such as potassium phosphate, etc., amines such as trimethylamine, triethylamine, diisopropylamine, n-butylamine, diisopropylethylamine, etc. Among these, from the viewpoint of efficiently obtaining the target product, preferred bases are carbonate salts such as sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, potassium bicarbonate, etc., phosphate salts such as potassium phosphate, etc., and more preferably potassium carbonate and cesium carbonate. Regarding the usage amount of the above base, relative to the compound represented by the formula (15), it is usually about 2 to 20 equivalents, preferably 1 to 20 equivalents, and more preferably 2 to 8 equivalents.

[0145] As the solvent used in the first step, as long as it does not have an adverse effect on the reaction, there is no particular limitation. Specific examples thereof include aliphatic hydrocarbons (pentane, n-hexane, n-octane, n-decane, decalin, etc.), halogenated aliphatic hydrocarbons (chloroform, dichloromethane, dichloroethane, carbon tetrachloride, etc.), aromatic hydrocarbons (benzene, nitrobenzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, etc.), ethers (diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran (THF), dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc.), amides (N,N-dimethylformamide (DMF), N,N-dimethylacetamide, etc.), lactams and lactones (N-methylpyrrolidone, γ-butyrolactone, etc.), urea derivatives (N,N-dimethylimidazolidinone, tetramethylurea, etc.), sulfoxides (dimethyl sulfoxide, sulfolane, etc.), nitriles (acetonitrile, propionitrile, butyronitrile, etc.). Among these, from the viewpoint of efficiently obtaining the target substance, preferred solvents are aliphatic hydrocarbons (pentane, n-hexane, n-octane, n-decane, decalin, etc.), aromatic hydrocarbons (benzene, nitrobenzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, etc.), ethers (diethyl ether, diisopropyl ether, tert-butyl methyl ether, THF, dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc.), and more preferably aromatic hydrocarbons (benzene, nitrobenzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, etc.), ethers (diethyl ether, diisopropyl ether, tert-butyl methyl ether, THF, dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc.).

[0146] Regarding the feed ratio of the compound represented by the formula (15), the compound represented by the formula (16-1), and the compound represented by the formula (16-2), relative to the compound represented by the formula (15), the total of the compound represented by the formula (16-1) and the compound represented by the formula (16-2) is preferably 2 to 6 equivalents, more preferably 2 to 3 equivalents. The compound represented by the formula (16-1) and the compound represented by the formula (16-2) may be the same as or different from each other.

[0147] In the first step, regarding the reaction temperature, while considering the types and amounts of the raw material compounds and the catalyst used, it is appropriately set within the range from the melting point to the boiling point of the solvent, usually about 0 to 200 °C, preferably 0 to 50 °C. In addition, the reaction time varies depending on the raw material compounds used, the reaction temperature, etc., and thus cannot be generally specified, usually about 1 to 24 hours.

[0148] In Scheme A, the second step is a step of reducing the intermediate represented by the formula (17) to obtain the intermediate represented by the formula (18). As the reduction method, known methods such as catalytic hydrogenation and chemical reduction using a metal and an acid can be cited.

[0149] In the case of reduction by catalytic hydrogenation, known catalysts such as palladium on carbon, Raney nickel catalyst, platinum oxide, ruthenium on carbon, rhodium on carbon, and platinum on carbon can be used. In addition, as the conditions for catalytic hydrogenation, for example, a hydrogen pressure of 1 to 10 atmospheres, a reaction temperature of 20 to 100 °C, and a reaction time of 1 to 48 hours can be cited.

[0150] In Scheme A, the third step is a step of reacting the intermediate represented by the formula (18) with the compound represented by the formula (19-1) and the compound represented by the formula (19-2) to synthesize the fluorene derivative represented by the formula (1).

[0151] In the third step, a base can be used. As the above base, the same bases as those that can be used in the first step can be cited. Among these, particularly from the viewpoint of ease of handling, triethylamine, pyridine, diisopropylethylamine, etc. are preferred.

[0152] The reaction solvent is preferably an aprotic organic solvent, and examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, tetrahydrofuran, dioxane, etc. From the viewpoint of ease of removing the reaction solvent after the reaction, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, dioxane, toluene, xylene, mesitylene, etc. are preferred.

[0153] Regarding the feed ratio of the intermediate represented by the formula (18) to the compound represented by the formula (19-1) and the compound represented by the formula (19-2), the total of the compound represented by the formula (19-1) and the compound represented by the formula (19-2) is preferably 2 to 6 equivalents, more preferably 2 to 3 equivalents, relative to the intermediate represented by the formula (18). The compound represented by the formula (19-1) and the compound represented by the formula (19-2) may be the same as or different from each other.

[0154] In the third step, regarding the reaction temperature, it is appropriately set within the range from the melting point to the boiling point of the solvent while considering the types and amounts of the raw material compounds and the catalyst used, and is usually about 0 to 200 °C, preferably 0 to 50 °C. In addition, the reaction time varies depending on the raw material compounds used, the reaction temperature, etc., and thus cannot be generally specified, and is usually about 1 to 24 hours.

[0155] After the reaction is completed, post-treatment is carried out by a conventional method, and the target fluorene derivative can be obtained.

[0156] Furthermore, the compound represented by the formula (19-1) and the compound represented by the formula (19-2) can be obtained by a known method or by purchasing commercially available products.

[0157] [Charge transport material]

[0158] The fluorene derivative of the present invention can preferably be used as a charge transporting material, particularly a hole transporting material. In the present invention, the so-called charge transportability is synonymous with conductivity. The so-called charge transporting material refers to a material that has charge transportability by itself. In addition, the so-called charge transporting varnish can be a varnish that has charge transportability by itself, or a varnish in which the solid film obtained therefrom has charge transportability.

[0159] [Charge transporting varnish]

[0160] The charge transporting varnish of the present invention contains a charge transporting material composed of the above-mentioned fluorene derivative and an organic solvent. The above-mentioned charge transporting material can be used alone or in combination of two or more.

[0161] [Organic solvent]

[0162] As the above-mentioned organic solvent, a highly polar solvent that can dissolve the above-mentioned fluorene derivative well can be used. Regarding the fluorene derivative of the present invention, it can be dissolved in a solvent regardless of the polarity of the solvent. In addition, if necessary, a low-polarity solvent can be used in consideration of more excellent process suitability compared with a highly polar solvent. In the present invention, the so-called low-polarity solvent is defined as a solvent having a relative dielectric constant of less than 7 at a frequency of 100 kHz, and the so-called highly polar solvent is defined as a solvent having a relative dielectric constant of 7 or more at a frequency of 100 kHz.

[0163] As the above-mentioned low-polarity solvent, for example, chloroform, chlorobenzene and other chlorine-based solvents; toluene, xylene, tetralin, cyclohexylbenzene, decylbenzene and other aromatic hydrocarbon-based solvents; 1-octanol, 1-nonanol, 1-decanol and other aliphatic alcohol-based solvents; tetrahydrofuran, dioxane, anisole, 4-methoxytoluene, 3-phenoxytoluene, dibenzyl ether, diethylene glycol dimethyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether and other ether-based solvents; methyl benzoate, ethyl benzoate, butyl benzoate, isoamyl benzoate, bis(2-ethylhexyl) phthalate, dibutyl maleate, dibutyl oxalate, hexyl acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate and other ester-based solvents, etc.

[0164] As the above-mentioned high-polarity solvents, for example, amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutyramide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc.; ketone solvents such as methyl ethyl ketone, isophorone, cyclohexanone, etc.; nitrile solvents such as acetonitrile, 3-methoxypropionitrile, etc.; polyol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-butanediol, 2,3-butanediol, etc.; monohydric alcohol solvents other than aliphatic alcohols such as diethylene glycol monomethyl ether, diethylene glycol monophenyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, benzyl alcohol, 2-phenoxyethanol, 2-benzyloxyethanol, 3-phenoxybenzyl alcohol, tetrahydrofurfuryl alcohol, etc.; sulfoxide solvents such as dimethyl sulfoxide, etc.

[0165] Regarding the usage amount of the above-mentioned solvents, from the viewpoints of suppressing the precipitation of the charge-transporting substance and ensuring a sufficient film thickness at the same time, the solid content concentration in the varnish of the present invention usually becomes about 0.1 to 20% by mass, preferably about 0.5 to 10% by mass. It should be noted that the solid content here refers to the components other than the solvent in the components contained in the varnish. The above-mentioned solvents can be used alone or in combination of two or more.

[0166] [Dopant (charge-accepting dopant)]

[0167] For the purpose of improving the charge transport property of the thin film obtained from the charge-transporting varnish of the present invention, etc., the charge-transporting varnish of the present invention may contain a dopant. As the dopant, as long as it is soluble in at least one solvent used in the composition, there is no particular limitation, and both inorganic dopants and organic dopants can be used. Furthermore, the dopant may be a substance in which, during the process of obtaining a charge-transporting thin film as a solid film from the composition, for example, due to an external stimulus such as heating during firing, a part of the molecule falls off, and thus the function of the dopant is initially manifested or enhanced. For example, it may be an aryl sulfonate compound in which a sulfonic acid group is protected by an easily detachable group.

[0168] As the above-mentioned inorganic dopant, a heteropoly acid is preferred, and as specific examples thereof, phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, phosphotungstomolybdic acid, silicotungstic acid, etc. can be cited.

[0169] A heteropoly acid is a polyacid formed by condensation of an isopolyacid of an oxyacid of vanadium (V), molybdenum (Mo), tungsten (W), etc. and an oxyacid of a different element, and has a structure in which a heteroatom is located at the center of the molecule, typically shown by the following formula (HPA1) of the Keggin type or the following formula (HPA2) of the Dawson type. As the oxyacid of such a different element, oxyacids of silicon (Si), phosphorus (P), and arsenic (As) can be mainly cited.

[0170] [Chemical formula 27]

[0171]

[0172] Examples of the above heteropolyacid include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, phosphotungstomolybdic acid, etc. These heteropolyacids can be used individually, or two or more of them can be used in combination. Further, the heteropolyacid used in the present invention is commercially available, and can also be synthesized by a known method. In particular, when using one heteropolyacid, this one heteropolyacid is preferably phosphotungstic acid or phosphomolybdic acid, and most preferably phosphotungstic acid. Further, when using two or more heteropolyacids, one of the two or more heteropolyacids is preferably phosphotungstic acid or phosphomolybdic acid, and more preferably phosphotungstic acid.

[0173] It should be noted that in quantitative analysis such as elemental analysis, even if the number of elements is more or less than that represented by the general formula, as long as it is a commercially available heteropolyacid or a heteropolyacid appropriately synthesized according to a known synthesis method, it can be used in the present invention.

[0174] That is, for example, generally, phosphotungstic acid is represented by the chemical formula H 3 (PW 12 O 40 )·nH 2 O, and phosphomolybdic acid is represented by the chemical formula H 3 (PMo 12 O 40 )·nH 2 O. In quantitative analysis, even if the number of P (phosphorus), O (oxygen), W (tungsten), or Mo (molybdenum) in this formula is more or less, as long as it is a product obtained commercially or a product appropriately synthesized according to a known synthesis method, it can be used in the present invention. In this case, the mass of the heteropolyacid defined in the present invention is not the mass of pure phosphotungstic acid (phosphotungstic acid content) in the synthesized product or commercially available product, but the total mass in a state containing water of hydration (hydrated water), other impurities, etc. in the form available commercially and the form separable by a known synthesis method.

[0175] Examples of the above organic dopant include arylsulfonic acid, arylsulfonate, an ionic compound composed of a specified anion and its counter cation, tetracyanoquinodimethane derivative, benzoquinone derivative, etc.

[0176] As the above arylsulfonic acid compound, from the viewpoint of the transparency of the film obtained from the charge transporting varnish of the present invention, it is preferably represented by the following formula (A) or (B).

[0177] [Chemical formula 28]

[0178]

[0179] In formula (A), A 1 is -O- or -S-, preferably -O-. A 2 is a (p 2 +1)-valent group derived from naphthalene or anthracene (i.e., a group obtained by removing p 2 +1 hydrogen atoms from naphthalene or anthracene), preferably a group derived from naphthalene. A 3 is a 2- to 4-valent perfluorobiphenyl group. p 1 is the number of bonding sites of A 1 to A 3 , and is an integer satisfying 2 ≦ p 1 ≦ 4, preferably A 3 is a 2-valent perfluorobiphenyl group and p 1 is 2. p 2 is the number of sulfonic acid groups bonded to A 2 , and is an integer satisfying 1 ≦ p 2 ≦ 4, preferably 2.

[0180] In formula (B), A 4 to A 8 are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, or a halogenated alkenyl group having 2 to 20 carbon atoms, and at least 3 of A 4 to A 8 are halogen atoms. q is the number of sulfonic acid groups bonded to the naphthalene ring, and is an integer satisfying 1 ≦ q ≦ 4, preferably 2 to 4, more preferably 2.

[0181] Examples of the halogenated alkyl group having 1 to 20 carbon atoms include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, a 3,3,3-trifluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a perfluoropropyl group, a 4,4,4-trifluorobutyl group, a 3,3,4,4,4-pentafluorobutyl group, a 2,2,3,3,4,4,4-heptafluorobutyl group, a perfluorobutyl group, etc. Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include a perfluoroethenyl group, a 1-perfluoropropenyl group, a perfluoroallyl group, a perfluorobutenyl group, etc.

[0182] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., preferably a fluorine atom. Examples of the alkyl group having 1 to 20 carbon atoms include the same groups as those described in the descriptions of R A and R B in formula (6).

[0183] Among these, as A 4 to A 8 , preferably a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms, and A 4 to A8 At least three of them are fluorine atoms, more preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 5 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms or a fluoroalkenyl group having 2 to 5 carbon atoms, and A 4 ~A 8 At least three of them are fluorine atoms, still more preferably a hydrogen atom, a fluorine atom, a cyano group, a perfluoroalkyl group having 1 to 5 carbon atoms or a perfluoroalkenyl group having 1 to 5 carbon atoms, and A 4 、A 5 and A 8 are fluorine atoms. It should be noted that a perfluoroalkyl group is a group in which all hydrogen atoms of an alkyl group are replaced by fluorine atoms, and a perfluoroalkenyl group is a group in which all hydrogen atoms of an alkenyl group are replaced by fluorine atoms.

[0184] As specific examples of the preferred arylsulfonic acid, the following examples are shown, but are not limited thereto.

[0185] [Chemical formula 29]

[0186]

[0187] As the above arylsulfonate compound, from the viewpoint of the transparency of the film obtained from the charge transporting varnish of the present invention, arylsulfonate compounds disclosed in International Publication No. 2017 / 217455, arylsulfonate compounds disclosed in International Publication No. 2017 / 217457, arylsulfonate compounds described in Japanese Patent Application No. 2017-243631, etc. can be mentioned.

[0188] Specifically, from the viewpoint of solubility in a low-polarity solvent, as the arylsulfonate compound, those represented by any one of the following formulas (C) to (E) are preferred.

[0189] [Chemical formula 30]

[0190]

[0191] In formulas (C) to (E), m is an integer satisfying 1 ≦ m ≦ 4, preferably 2. n is an integer satisfying 1 ≦ n ≦ 4, preferably 2.

[0192] In formula (C), A 11 is an m-valent group derived from perfluorobiphenyl (that is, a group obtained by removing m fluorine atoms from perfluorobiphenyl). A 12 is -O- or -S-, preferably -O-. A 13 is an (n + 1)-valent group derived from naphthalene or anthracene (that is, a group obtained by removing n + 1 hydrogen atoms from naphthalene or anthracene), preferably a group derived from naphthalene. R s1 ~R s4Each independently represents a hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms, R s5 is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted.

[0193] As the linear or branched alkyl group having 1 to 6 carbon atoms represented by R s1 to R s4 Examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl and the like. Among these, an alkyl group having 1 to 3 carbon atoms is preferred.

[0194] Regarding the monovalent hydrocarbon group having 2 to 20 carbon atoms represented by R s5 , it may be linear, branched or cyclic. Specific examples thereof include alkyl groups such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl; aryl groups such as phenyl, naphthyl, phenanthryl and the like.

[0195] In particular, among R s1 to R s4 , it is preferred that R s1 or R s3 is a linear alkyl group having 1 to 3 carbon atoms and the rest are hydrogen atoms; or R s1 is a linear alkyl group having 1 to 3 carbon atoms, and R s2 to R s4 are hydrogen atoms. In this case, as the linear alkyl group having 1 to 3 carbon atoms, methyl is preferred. In addition, as R s5 , a linear alkyl group having 2 to 4 carbon atoms or a phenyl group is preferred.

[0196] In formula (D), A 14 is a substituted m-valent hydrocarbon group having 6 to 20 carbon atoms containing one or more aromatic rings, and this hydrocarbon group is a group obtained by removing m hydrogen atoms from a hydrocarbon compound having 6 to 20 carbon atoms containing one or more aromatic rings. Examples of the above hydrocarbon compound include benzene, toluene, xylene, ethylbenzene, biphenyl, naphthalene, anthracene, phenanthrene and the like.

[0197] Furthermore, regarding the hydrocarbon group represented by A 14 , a part or all of the hydrogen atoms thereof may be further substituted by a substituent. Examples of such a substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a hydroxyl group, an amino group, a silanol group, a mercapto group, a carboxyl group, a sulfonate group, a phosphate group, a phosphate ester group, an ester group, a thioester group, an acylamino group, a monovalent hydrocarbon group, an organic oxy group, an organic amino group, an organosilyl group, an organic thio group, an acyl group, a sulfo group and the like. Among these, as A 14 , a group derived from benzene, biphenyl or the like is preferred.

[0198] In formula (D), A 15 is -O- or -S-, and -O- is preferred.

[0199] In formula (D), A 16 is an (n + 1)-valent aromatic hydrocarbon group having 6 to 20 carbon atoms, which is a group obtained by removing (n + 1) hydrogen atoms from the aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. Examples of the aromatic hydrocarbon compound include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, etc. Among them, as A 16 , a group derived from naphthalene or anthracene is preferred, and a group derived from naphthalene is more preferred.

[0200] In formula (D), R s6 and R s7 are each independently a hydrogen atom or a linear or branched monovalent aliphatic hydrocarbon group, and R s8 is a linear or branched monovalent aliphatic hydrocarbon group. However, the total number of carbon atoms of R s6 , R s7 and R s8 is 6 or more. There is no particular limitation on the upper limit of the total number of carbon atoms of R s6 , R s7 and R s8 , and it is preferably 20 or less, more preferably 10 or less.

[0201] Specific examples of the linear or branched monovalent aliphatic hydrocarbon group represented by R s6 , R s7 and R s8 include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, decyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, hexenyl, etc. Among these, R s6 is preferably a hydrogen atom, and R s7 and R s8 are each independently preferably an alkyl group having 1 to 6 carbon atoms.

[0202] In formula (E), R s9 to R s13 are each independently a hydrogen atom, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms.

[0203] Regarding the alkyl group having 1 to 10 carbon atoms represented by R s9 to R s13 , it can be linear, branched or cyclic. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, etc.

[0204] From R s9 to R s13 The halogenated alkyl group having 1 to 10 carbon atoms represented by is not particularly limited as long as it is a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 10 carbon atoms are substituted by halogen atoms. Specific examples thereof include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl, 2,2,3,3,3-pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3,4,4,4-pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl, 1,1,2,2,3,3,4,4,4-nonafluorobutyl, etc.

[0205] As the one represented by R s9 to R s13 The halogenated alkenyl group having 2 to 10 carbon atoms represented by is not particularly limited as long as it is a group in which part or all of the hydrogen atoms of the alkenyl group having 2 to 10 carbon atoms are substituted by halogen atoms. Specific examples thereof include perfluoroethenyl, perfluoro-1-propenyl, perfluoro-2-propenyl, perfluoro-1-butenyl, perfluoro-2-butenyl, perfluoro-3-butenyl, etc.

[0206] Among these, as R s9 , nitro, cyano, halogenated alkyl group having 1 to 10 carbon atoms, halogenated alkenyl group having 2 to 10 carbon atoms are preferred, nitro, cyano, halogenated alkyl group having 1 to 4 carbon atoms, halogenated alkenyl group having 2 to 4 carbon atoms are more preferred, and nitro, cyano, trifluoromethyl, perfluoropropenyl are further preferred. As R s10 to R s13 , a halogen atom is preferred, and a fluorine atom is more preferred.

[0207] In formula (E), A 17 is -O-, -S- or -NH-, and -O- is preferred.

[0208] In formula (E), A 18 is an (n + 1)-valent aromatic hydrocarbon group having 6 to 20 carbon atoms, and this aromatic hydrocarbon group is a group obtained by removing (n + 1) hydrogen atoms from the aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. Examples of the above aromatic hydrocarbon compounds include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, etc. Among these, as A 18 , a group derived from naphthalene or anthracene is preferred, and a group derived from naphthalene is more preferred.

[0209] In formula (E), R s14 to R s17Each independently is a hydrogen atom, or a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms in a straight chain or branched form. Examples of the monovalent aliphatic hydrocarbon group include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, hexenyl. Among these, an alkyl group having 1 to 20 carbon atoms is preferred, an alkyl group having 1 to 10 carbon atoms is more preferred, and an alkyl group having 1 to 8 carbon atoms is further preferred.

[0210] In formula (E), R s18 is a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms in a straight chain or branched form, or -OR s19 . R s19 is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted.

[0211] Examples of the monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms in a straight chain or branched form represented by R s18 include the same groups as those described in the description of R s14 to R s17 . When R s18 is a monovalent aliphatic hydrocarbon group, R s18 is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and further preferably an alkyl group having 1 to 8 carbon atoms.

[0212] Examples of the monovalent hydrocarbon group having 2 to 20 carbon atoms represented by R s19 include aryl groups such as phenyl, naphthyl, and phenanthryl, in addition to the groups other than methyl among the above monovalent aliphatic hydrocarbon groups. Among these, R s19 is preferably a straight-chain alkyl group having 2 to 4 carbon atoms or phenyl.

[0213] Furthermore, examples of the substituents that the monovalent hydrocarbon group may have include a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group, and a cyano group.

[0214] As specific examples of the preferred aryl sulfonate compound, the following examples are shown, but are not limited thereto.

[0215] [Chemical formula 31]

[0216]

[0217] As the ionic compound composed of the specified anion and its counter cation, from the aspect of the transparency of the film obtained from the charge transporting varnish of the present invention, an ionic compound represented by the following formula (F) is preferred.

[0218] [Chemical formula 32]

[0219]

[0220] In formula (F), E is an element of Group 13 of the long-period periodic table, Ar 101 ~Ar 104 Each independently represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, and may be substituted with a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom, a cyano group, a nitro group, an acyl group having 2 to 12 carbon atoms such as an acetyl group, or a haloalkyl group having 1 to 10 carbon atoms such as a trifluoromethyl group.

[0221] As the Group 13 element represented by E, a boron atom, an aluminum atom, or a gallium atom is preferable, and a boron atom is more preferable. As the aryl group having 6 to 20 carbon atoms represented by Ar 101 ~Ar 104 The same groups as those described in the explanations of Ar 1 and Ar 2 in formula (1) can be exemplified. As the heteroaryl group having 2 to 20 carbon atoms represented by Ar 101 ~Ar 104 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 2-imidazolyl, 4-imidazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, etc. can be exemplified.

[0222] In formula (F), M + is an onium ion. As the above onium ion, an iodonium ion, a sulfonium ion, an ammonium ion, a phosphonium ion, etc. can be exemplified, and an iodonium ion represented by the following formula (G) is particularly preferable.

[0223] [Chemical formula 33]

[0224]

[0225] In formula (G), R 101 and R 102 Each independently represents an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, and may be substituted with a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms.

[0226] Examples of the above-mentioned tetracyanoquinodimethane derivatives include 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), tetrachloro-7,7,8,8-tetracyanoquinodimethane, 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2-chloro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, 2,5-dichloro-7,7,8,8-tetracyanoquinodimethane, and the like.

[0227] Examples of the above-mentioned benzoquinone derivatives include tetrachloro-1,4-benzoquinone (tetrachlorobenzoquinone), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and the like.

[0228] When the charge-transporting varnish of the present invention contains a dopant, its content varies depending on the type of dopant, the desired charge transport properties, etc., and thus cannot be generally specified. In terms of the mass ratio relative to the charge-transporting substance 1, it is usually about 0.01 to 50, preferably about 0.1 to 10, and more preferably about 1.0 to 5.0.

[0229] For the purpose of adjusting the film physical properties of the obtained charge-transporting film, etc., the charge-transporting varnish of the present invention may further contain an organosilane compound. Examples of the above-mentioned organosilane compound include a dialkoxysilane compound, a trialkoxysilane compound, or a tetraalkoxysilane compound. In particular, as the organosilane compound, a dialkoxysilane compound or a trialkoxysilane compound is preferred, and a trialkoxysilane compound is more preferred. The organosilane compound can be used alone or in combination of two or more.

[0230] When an organosilane compound is contained, in terms of its content, it is usually about 0.1 to 50% by mass relative to the total mass of the charge-transporting substance and the dopant. If considering suppressing the reduction of the charge transport property of the obtained film and improving the hole injection ability in the layer (such as a hole transport layer, a light-emitting layer) laminated on the opposite side of the anode in contact with the hole injection layer formed of the charge-transporting film of the present invention, it is preferably about 0.5 to 40% by mass, more preferably about 0.8 to 30% by mass, and further preferably about 1 to 20% by mass.

[0231] The method for preparing the charge transporting varnish is not particularly limited. For example, a method of adding the above-mentioned fluorene derivative and a dopant used as needed in any order or simultaneously to an organic solvent can be cited. Additionally, when there are multiple organic solvents, the above-mentioned fluorene derivative and a dopant used as needed can first be dissolved in one solvent, and then other solvents can be added thereto, or the above-mentioned fluorene derivative and a dopant used as needed can be dissolved successively or simultaneously in a mixed solvent of multiple organic solvents.

[0232] Regarding the charge transporting varnish of the present invention, from the viewpoint of reproducibly obtaining a film with higher flatness, it is preferable to filter using a submicron filter or the like after dissolving the above-mentioned fluorene derivative and a dopant used as needed in an organic solvent.

[0233] The viscosity of the charge transporting varnish of the present invention is generally 1 to 50 mPa·s at 25°C. Additionally, the surface tension of the charge transporting varnish of the present invention is generally 20 to 50 mN / m at 25°C. It should be noted that the viscosity is a value measured using a TVE-25 type viscometer manufactured by Toki Sangyo Co., Ltd. The surface tension is a value measured using an automatic surface tensiometer CBVP-Z type manufactured by Kyowa Interface Science Co., Ltd. Regarding the viscosity and surface tension of the varnish, various factors such as the desired film thickness can be considered, and they can be adjusted by changing the types of the above-mentioned solvents, their ratios, the solid content concentration, etc.

[0234] [Charge Transporting Film]

[0235] By coating and firing the charge transporting varnish of the present invention on a substrate, a charge transporting film of the present invention can be formed.

[0236] As the method for coating the varnish, dip coating, spin coating, transfer printing, roll coating, brush coating, inkjet printing, spraying, slot coating, etc. can be cited, but it is not limited to these. It is preferable to adjust the viscosity and surface tension of the varnish according to the coating method.

[0237] Additionally, the firing atmosphere of the coated charge transporting varnish is not particularly limited. A film with a uniform film-forming surface and high charge transportability can be obtained not only in an atmospheric atmosphere but also in an inert gas such as nitrogen or in a vacuum. Depending on the type of dopant used together, by firing the varnish in an atmospheric atmosphere, a film with charge transportability can sometimes be obtained with good reproducibility.

[0238] Regarding the firing temperature, it is appropriately set within the range of about 100 to 260 °C in consideration of the use of the obtained thin film, the degree of charge transport property imparted to the obtained thin film, the type of solvent, the boiling point, etc. When the obtained thin film is used as the hole injection layer of an organic EL element, it is preferably about 140 to 250 °C, more preferably about 145 to 240 °C. For the charge transport varnish of the present invention, even at a low firing temperature of 200 °C or lower, a thin film having good charge transport property can be obtained. Further, during firing, in order to exhibit higher uniform film-forming property or to cause a reaction on the substrate, etc., a temperature change of two or more stages can be applied, and heating can be performed using an appropriate device such as a hot plate or an oven.

[0239] There is no particular limitation on the film thickness of the charge transport thin film. When it is used as the hole injection layer, hole transport layer or hole injection transport layer of an organic EL element, it is preferably 5 to 300 nm. As a method of changing the film thickness, there are methods such as changing the solid content concentration in the varnish or changing the amount of solution on the substrate during coating.

[0240] Regarding the charge transport thin film of the present invention, expressed by the average value in the wavelength region of 400 to 800 nm, it shows a refractive index of 1.6 or more and an extinction coefficient of 0.030 or less. In one aspect, it shows a refractive index of 1.65 or more, and in another aspect, it shows a refractive index of 1.70 or more. Further, in one aspect, it shows an extinction coefficient of 0.020 or less, and in another aspect, it shows an extinction coefficient of 0.005 or less.

[0241] [Organic EL element]

[0242] The organic EL element of the present invention has a pair of electrodes, and a functional layer composed of the charge transport thin film of the present invention is provided between these electrodes.

[0243] As a representative configuration of the organic EL element, the following (a) to (f) can be cited, but it is not limited to these. It should be noted that in the following configurations, an electron blocking layer, etc. can be provided between the light-emitting layer and the anode as needed, and a hole (hole) blocking layer, etc. can be provided between the light-emitting layer and the cathode. In addition, the hole injection layer, hole transport layer or hole injection transport layer can also function as an electron blocking layer, etc., and the electron injection layer, electron transport layer or electron injection transport layer can also function as a hole blocking layer, etc. Further, as needed, an arbitrary functional layer can be provided between each layer.

[0244] (a) Anode / Hole injection layer / Hole transport layer / Light-emitting layer / Electron transport layer / Electron injection layer / Cathode

[0245] (b) Anode / Hole injection layer / Hole transport layer / Light-emitting layer / Electron injection transport layer / Cathode

[0246] (c) Anode / Hole injection transport layer / Light-emitting layer / Electron transport layer / Electron injection layer / Cathode

[0247] (d) Anode / Hole injection transport layer / Light-emitting layer / Electron injection transport layer / Cathode

[0248] (e) Anode / Hole injection layer / Hole transport layer / Light-emitting layer / Cathode

[0249] (f) Anode / Hole injection transport layer / Light-emitting layer / Cathode

[0250] The "hole injection layer", "hole transport layer", and "hole injection transport layer" are layers formed between the light-emitting layer and the anode, and have the function of transporting holes from the anode to the light-emitting layer. When only one layer of hole-transporting material is provided between the light-emitting layer and the anode, it is the "hole injection transport layer". When two or more layers of hole-transporting material are provided between the light-emitting layer and the anode, the layer close to the anode is the "hole injection layer", and the other layers are the "hole transport layer". In particular, the hole injection (transport) layer uses a thin film that not only has excellent hole acceptance from the anode but also has excellent hole injection into the hole transport (light-emitting) layer.

[0251] The "electron injection layer", "electron transport layer", and "electron injection transport layer" are layers formed between the light-emitting layer and the cathode, and have the function of transporting electrons from the cathode to the light-emitting layer. When only one layer of electron-transporting material is provided between the light-emitting layer and the cathode, it is the "electron injection transport layer". When two or more layers of electron-transporting material are provided between the light-emitting layer and the cathode, the layer close to the cathode is the "electron injection layer", and the other layers are the "electron transport layer".

[0252] The "light-emitting layer" is an organic layer having a light-emitting function. In the case of an admixture system, it contains a host material and a dopant material. At this time, the host material mainly has the functions of promoting the recombination of electrons and holes and confining excitons within the light-emitting layer, and the dopant material has the function of efficiently emitting light from the excitons obtained through recombination. In the case of a phosphorescent element, the host material mainly has the function of confining the excitons generated by the dopant within the light-emitting layer.

[0253] The charge-transporting thin film of the present invention can preferably be used as a functional layer provided between the anode and the light-emitting layer in an organic EL element, can more preferably be used as a hole injection layer, a hole transport layer, or a hole injection transport layer, and can further preferably be used as a hole injection layer.

[0254] As materials and production methods for producing an organic EL element using the charge transporting varnish of the present invention, the following materials and production methods can be cited, but are not limited thereto.

[0255] An example of a production method of an organic EL element having a hole injection layer composed of a charge transporting film obtained from the charge transporting varnish of the present invention is as follows. It should be noted that for the electrode, it is preferable to perform cleaning using alcohol, pure water, etc. and surface treatment such as UV ozone treatment and oxygen-plasma treatment in a range that does not cause adverse effects on the electrode.

[0256] On the anode substrate, using the above method, a hole injection layer is formed using the charge transporting varnish of the present invention. It is introduced into a vacuum evaporation apparatus, and a hole transporting layer, a light emitting layer, an electron transporting layer / hole blocking layer, an electron injection layer, and a cathode metal are sequentially evaporated. Alternatively, in this method, instead of forming the hole transporting layer and the light emitting layer by evaporation, a composition for forming a hole transporting layer containing a hole transporting polymer and a composition for forming a light emitting layer containing a light emitting polymer are used, and these layers are formed by a wet method. Further, if necessary, an electron blocking layer can be provided between the light emitting layer and the hole transporting layer.

[0257] Examples of the above anode material include transparent electrodes represented by indium tin oxide (ITO) and indium zinc oxide (IZO), metal anodes composed of metals represented by aluminum, or their alloys, etc., and preferably anode materials that have been planarized. Polythiophene derivatives and polyaniline derivatives having high charge transportability can also be used. Further, examples of other metals constituting the metal anode include gold, silver, copper, indium, and their alloys, etc., but are not limited thereto.

[0258] Examples of the material for forming the above hole transporting layer include (triphenylamine) dimer derivatives, [(triphenylamine) dimer] spiro dimers, N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine (α-NPD), 4,4',4''-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA), 4,4',4''-tris[1-naphthalenyl(phenyl)amino]triphenylamine (1-TNATA), etc. triarylamines, and oligothiophenes such as 5,5''-bis-{4-[bis(4-methylphenyl)amino]phenyl}-2,2':5',2''-terthiophene (BMA-3T).

[0259] Examples of the materials for forming the above-mentioned light-emitting layer include low-molecular-weight light-emitting materials such as metal complexes like aluminum complexes of 8-hydroxyquinoline, metal complexes of 10-hydroxybenzo[h]quinoline, distyrylbenzene derivatives, distyrylarylene derivatives, metal complexes of (2-hydroxyphenyl)benzothiazole, and silole derivatives; systems formed by mixing light-emitting materials and electron-transporting materials in high-molecular compounds such as poly(p-phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly(3-alkylthiophene), and polyvinylcarbazole, etc., but are not limited thereto.

[0260] In addition, when forming the light-emitting layer by vapor deposition, it can be co-vapor deposited with a light-emitting dopant. Examples of the above-mentioned light-emitting dopant include metal complexes such as tris(2-phenylpyridine)iridium(III) (Ir(ppy) 3 ), etc., tetracene derivatives such as rubrene, quinacridone derivatives, condensed polycyclic aromatic rings such as perylene, etc., but are not limited thereto.

[0261] Examples of the materials for forming the above-mentioned electron-transporting layer / hole-blocking layer include oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, pyrimidine derivatives, etc., but are not limited thereto.

[0262] Examples of the materials for forming the above-mentioned electron-injection layer include metal oxides such as lithium oxide (Li 2 O), magnesium oxide (MgO), aluminum oxide (Al 2 O 3 ), etc., metal fluorides such as lithium fluoride (LiF), sodium fluoride (NaF), etc., but are not limited thereto.

[0263] Examples of the above-mentioned cathode materials include aluminum, magnesium-silver alloy, aluminum-lithium alloy, etc., but are not limited thereto.

[0264] Examples of the materials for forming the above-mentioned electron-blocking layer include tris(phenylpyrazole)iridium, etc., but are not limited thereto.

[0265] Examples of the above hole-transporting polymers include poly[(9,9-dihexylfluorene-2,7-diyl)-co-(N,N'-bis{4-butylphenyl}-1,4-diaminophenylene)], poly[(9,9-dioctylfluorene-2,7-diyl)-co-(N,N'-bis{4-butylphenyl}-1,1'-biphenyl-4,4-diamine)], poly[(9,9-bis{1'-penten-5'-yl}fluorene-2,7-diyl)-co-(N,N'-bis{4-butylphenyl}-1,4-diaminophenylene)], poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] capped with polysilsesquioxane, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-butylphenyl))diphenylamine)], and the like.

[0266] Examples of the above light-emitting polymers include polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), poly(phenylenevinylene) derivatives such as poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), polyvinylcarbazole (PVCz), and the like.

[0267] The materials constituting the anode, cathode, and the layers formed therebetween vary depending on whether the device is a bottom-emission structure or a top-emission structure. Therefore, the materials are appropriately selected in consideration of this point.

[0268] Generally, for a device with a bottom-emission structure, a transparent anode is used on the substrate side and light is extracted from the substrate side. For a device with a top-emission structure, a reflective anode made of metal is used and light is extracted from the transparent electrode (cathode) side opposite to the substrate. Therefore, for example, for the anode material, a transparent anode such as ITO is used when manufacturing a device with a bottom-emission structure, and a reflective anode such as Al / Nd is used when manufacturing a device with a top-emission structure.

[0269] Regarding the organic EL device of the present invention, in order to prevent deterioration of characteristics, it can be sealed together with a water scavenger or the like according to a conventional method as needed.

[0270] As described above, the charge-transporting varnish of the present invention is preferably used for forming the functional layer of an organic EL device. In addition, it can also be used for forming the functional layer in electronic devices such as organic photoelectric conversion devices, organic thin-film solar cells, organic perovskite photoelectric conversion devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic optical detectors, organic optical receivers, organic electrochromic elements, light-emitting electrochemical cells, quantum dot light-emitting diodes, quantum lasers, organic laser diodes, and organic plasmonic light-emitting elements.

[0271] Example

[0272] Examples are listed below to illustrate the present invention more specifically, but the present invention is not limited to the following examples. It should be noted that the devices used are as described below.

[0273] (1) 1 H-NMR: Bruker BioSpin Corporation, nuclear magnetic resonance spectrometer AVANCE III HD 500 MHz

[0274] (2) Substrate cleaning: Choshu Sangyo Co., Ltd., substrate cleaning apparatus (reduced-pressure plasma method)

[0275] (3) Coating of varnish: Mikasa Co., Ltd., spin coater MS-A100

[0276] (4) Film thickness measurement: Kosaka Laboratory Ltd., micro shape measuring machine Surf Coater ET-4000

[0277] (5) Fabrication of EL element: Choshu Sangyo Co., Ltd., multi-functional evaporation apparatus system C-E2L1G1-N

[0278] (6) Measurement of brightness etc. of EL element: H.C.C. Co., Ltd., multi-channel IVL measuring apparatus

[0279] (7) Lifetime measurement of EL element (measurement of brightness half-life): H.C.C. Co., Ltd., organic EL brightness lifetime evaluation system PEL-105S

[0280] (8) Measurement of refractive index and extinction coefficient: J.A. Woollam Japan, multi-angle spectroscopic ellipsometer VASE

[0281] [1] Synthesis of compound

[0282] [Synthesis Example 1] Synthesis of intermediate A

[0283] [Chemical Formula 34]

[0284]

[0285] Synthesis was carried out according to the method described in J. Mater. Chem. C, 2014, pages 1068 - 1075, to obtain intermediate A (2,7-dibromo-9,9-bis(4-nitrophenyl)-9H-fluorene).

[0286] [Example 1-1] Synthesis of fluorene derivative A

[0287] [Example 1-1-1] Synthesis of intermediate B

[0288] [Chemical Formula 35]

[0289]

[0290] Synthesis was carried out according to the method described in International Publication No. 2017 / 122649 to obtain Intermediate B (4,4'-(9,9-bis(4-nitrophenyl)-9H-fluoren-2,7-diyl)bis(N,N-diphenylaniline)).

[0291] [Example 1-1-2] Synthesis of Intermediate C

[0292] [Chemical Formula 36]

[0293]

[0294] Synthesis was carried out according to the method described in International Publication No. 2017 / 122649 to obtain Intermediate C (4,4'-(9,9-bis(4-aminophenyl)-9H-fluoren-2,7-diyl)bis(N,N-diphenylamine)).

[0295] [Example 1-1-3] Synthesis of Fluorene Derivative A

[0296] [Chemical Formula 37]

[0297]

[0298] Intermediate C (1 g, 1.2 mmol), THF (2 mL) and trimethylamine (368 μL, 2.64 mmol) were placed in a reaction vessel. After nitrogen replacement, while cooling with an ice bath, 1-naphthoyl chloride (396 μL, 2.6 mmol) was added dropwise. After the addition was completed, the mixture was stirred at room temperature for 1 hour. Ion-exchanged water (25 mL) was added to the reaction mixture, and extraction was carried out with ethyl acetate (25 mL). The extraction operation was carried out 3 times. The organic layer was dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure. The concentrated solution was dropped into 2-propanol (20 mL), and the suspension was stirred at room temperature. Filtration was carried out, and the filtrate was dried to obtain 1.16 g (yield: 85%) of the target fluorene derivative A (N,N'-(2,7-bis(4-(diphenylamino)phenyl-9H-fluorene-9,9-diyl)bis(4,1-phenylene))bis(1-naphthamide)). The following shows 1 The measurement results of 1H-NMR.

[0299] 1H-NMR (500 MHz, DMSO-d6) δ [ppm]: 7.05 - 7.07 (m, 16H), 7.26 - 7.33 (m, 12H), 7.56 - 7.60 (m, 10H), 7.62 - 7.74 (m, 10H), 7.99 - 8.06 (m, 6H), 8.13 - 8.15 (m, 2H), 10.58 (brs, 2H).

[0300] [Example 1-2] Synthesis of Fluorene Derivative B

[0301] Except for using benzoyl chloride (304 μL, 2.64 mmol) instead of 1-naphthoyl chloride, the target fluorene derivative B (N,N'-(2,7-bis(4-(diphenylamino)phenyl)-9H-fluorene-9,9-diyl)bis(4,1-phenylene)) bisbenzamide) 1.07 g (yield: 85%) was obtained in the same manner as in Example 1-1-3. The following shows 1 the measurement results of H-NMR.

[0302] 1 H-NMR (500 MHz, DMSO-d6) δ [ppm]: 7.03 - 7.07 (m, 16H), 7.24 (d, J = 8.5 Hz, 4H), 7.29 - 7.33 (m, 8H), 7.49 - 7.52 (m, 4H), 7.55 - 7.61 (m, 6H), 7.69 - 7.73 (m, 8H), 7.90 (dd, J = 1.5 Hz, 8.5 Hz, 4H), 8.20 (d, J = 7.5 Hz, 2H), 10.24 (brs, 2H).

[0303] [Chemical Formula 38]

[0304]

[0305] [Example 1-3] Synthesis of Fluorene Derivative C

[0306] [Example 1-3-1] Synthesis of Intermediate D

[0307] [Chemical Formula 39]

[0308]

[0309] Synthesis was carried out according to the method described in International Publication No. 2017 / 122649 to obtain Intermediate D (3,3'-(9,9-bis(4-nitrophenyl)-9H-fluorene-2,7-diyl)bis(9-phenyl-9H-carbazole)).

[0310] [Example 1-3-2] Synthesis of Intermediate E

[0311] [Chemical Formula 40]

[0312]

[0313] Synthesis was carried out according to the method described in International Publication No. 2017 / 122649 to obtain Intermediate E (4,4'-(2,7-bis(9-phenyl-9H-carbazol-3-yl)-9H-fluorene-9,9-diyl)dianiline).

[0314] [Example 1-3-3] Synthesis of Fluorene Derivative C

[0315] [Chemical Formula 41]

[0316]

[0317] Except for using Intermediate E (1.13 g, 1.36 mmol) instead of Intermediate C, the target fluorene derivative C (N,N'-((2,7-bis(9-phenyl-9H-carbazol-3-yl)-9H-fluorene-9,9-diyl)bis(4,1-phenylene))bis(1-naphthamide)) 1.46 g (yield: 94%) was obtained by the same method as in Example 1-1-3. The following shows 1 the measurement results of 1H-NMR.

[0318] 1 1H-NMR (500 MHz, DMSO-d6) δ [ppm]: 7.32 (t, J = 7.0 Hz, 2H), 7.39 - 7.41 (m, 6H), 7.46 (t, J = 7.5 Hz, 4H), 7.54 - 7.58 (m, 8H), 7.65 - 7.72 (m, 10H), 7.78 - 7.80 (m, 6H), 7.91 - 7.99 (m, 6H), 8.04 (d, J = 8.5 Hz, 2H), 8.12 - 8.15 (m, 4H), 8.41 (d, J = 8.0 Hz, 2H), 8.65 (s, 2H), 10.59 (brs, 2H).

[0319] [Example 1-4] Synthesis of Fluorene Derivative D

[0320] [Example 1-4-1] Synthesis of Intermediate F

[0321] [Chemical Formula 42]

[0322]

[0323] Intermediate A (0.57 g, 1 mmol), 9-phenylcarbazole-2-boronic acid (0.63 g, 2.2 mmol), potassium carbonate (0.55 g, 4 mmol), 1,4-dioxane (11 mL), ion-exchanged water (2.8 mL), and Pd(PPh 3 )4 (57.8 mg, 0.05 mmol) were placed in a reaction vessel. After nitrogen replacement, the mixture was stirred at 90 °C for 3 hours. After cooling to room temperature, ion-exchanged water (8.4 mL) was added to the reaction mixture, followed by filtration. The filter cake was washed with ion-exchanged water (11 mL). The washing was carried out twice. 1,4-Dioxane (5.6 g) was added to the filter cake, and the mixture was stirred at 90 °C for 1 hour. After cooling to room temperature, filtration was performed, and the filter cake was washed with 1,4-dioxane (5.6 g) to obtain 0.68 g of the target intermediate F (2,2'-(9,9-bis(4-nitrophenyl)-9H-fluorene-2,7-diyl)bis(9-phenyl-9H-carbazole)) (yield: 76%).

[0324] [Example 1-4-2] Synthesis of Intermediate G

[0325] [Chemical Formula 43]

[0326]

[0327] Intermediate F (3 g, 3.3 mmol), DMF (60 mL), and 5% Pd / C (0.3 g) were placed in a reaction vessel. After hydrogen replacement, the mixture was stirred at room temperature for 48 hours. After nitrogen replacement, Celite filtration was carried out, and the filter cake was washed with DMF (30 mL). The filtrate was distilled under reduced pressure, and the concentrated solution was dropped into ethyl acetate (20 mL). The suspension was stirred at room temperature. Filtration was performed, and the filter cake was dried to obtain 2.10 g of the target intermediate G (4,4'-(2,7-bis(9-phenyl-9H-carbazol-2-yl)-9H-fluorene-9,9-diyl)diphenylamine) (yield: 77%).

[0328] [Example 1-4-3] Synthesis of Fluorene Derivative D

[0329] [Chemical Formula 44]

[0330]

[0331] Except for using intermediate G (0.9 g, 1.08 mmol) instead of intermediate A and using benzoyl chloride (274 μL, 2.38 mmol) instead of 1-naphthoyl chloride, the target fluorene derivative D (N,N'-((2,7-bis(9-phenyl-9H-carbazol-2-yl)-9H-fluorene-9,9-diyl)bis(4,1-phenylene))bisbenzamide) was obtained in the same manner as in Example 1-1-3 in a yield of 0.86 g (yield: 69%). The following shows 1 the measurement results of 1H-NMR.

[0332] 1 1H-NMR (500 MHz, DMSO-d6) δ [ppm]: 7.26 - 7.32 (m, 6H), 7.40 - 7.42 (m, 4H), 7.43 - 7.59 (m, 12H), 7.68 - 7.77 (m, 16H), 7.93 - 7.94 (m, 4H), 8.04 (d, J = 7.5 Hz, 2H), 8.27 (d, J = 7.5 Hz, 2H), 8.32 (d, J = 8.0 Hz, 2H), 10.26 (brs, 2H).

[0333] [Example 1-5] Synthesis of fluorene derivative E

[0334] [Chemical formula 45]

[0335]

[0336] Except for using 2-thiophenecarbonyl chloride (280 μL, 2.64 mmol) instead of 1-naphthoyl chloride, the target fluorene derivative E (N,N'-(2,7-bis(4-(diphenylamino)phenyl-9H-fluorene-9,9-diyl)bis(4,1-phenylene))bis(thiophene-2-carboxamide)) was obtained in the same manner as in Example 1-1-3 in a yield of 1.02 g (yield: 80%). The following shows 1 the measurement results of 1H-NMR.

[0337] 1H-NMR (500 MHz, DMSO-d6) δ [ppm]: 7.02 - 7.07 (m, 16H), 7.20 (dd, J = 4 Hz, 4.5 Hz, 2H), 7.23 (d, J = 9.0 Hz, 4H), 7.30 - 7.33 (m, 8H), 7.60 (d, J = 8.5 Hz, 4H), 7.64 (d, J = 8.5 Hz, 4H), 7.69 (s, 2H), 7.72 (d, J = 8.0 Hz, 2H), 7.83 (d, J = 5.0 Hz, 2H), 7.97 (d, J = 3.5 Hz, 2H), 8.01 (d, J = 8.5 Hz, 2H), 10.21 (brs, 2H).

[0338] [Example 1 - 6] Synthesis of Fluorene Derivative F

[0339] [Chemical Formula 46]

[0340]

[0341] Except for using benzothiophene-2-carbonyl chloride (517 mg, 2.64 mmol) instead of 1-naphthoyl chloride, the target fluorene derivative F (N,N'-(2,7-bis(4-(diphenylamino)phenyl)-9H-fluorene-9,9-diyl)bis(4,1-phenylene))bis(benzothiophene-2-carboxamide)) 1.14 g (yield: 83%) was obtained by the same method as in Example 1 - 1 - 3. The following shows 1 the measurement results of H-NMR.

[0342] 1 H-NMR (500 MHz, DMSO-d6) δ [ppm]: 7.03 - 7.07 (m, 16H), 7.26 - 7.33 (m, 12H), 7.44 - 7.50 (m, 4H), 7.61 (d, J = 8.5 Hz, 4H), 7.69 - 7.74 (m, 8H), 7.99 (d, J = 7.5 Hz, 2H), 8.03 (dd, J = 6.5 Hz, 8.0 Hz, 4H), 8.32 (s, 2H), 10.51 (brs, 2H).

[0343] [2] Preparation of Charge Transport Varnish

[0344] [Example 2 - 1] Preparation of Charge Transport Varnish A1

[0345] At room temperature, 174 mg of fluorene derivative A and 0.189 g of aryl sulfonate A represented by the following formula, synthesized according to the method described in International Publication No. 2017 / 217455, were stirred and dissolved in a mixed solvent of 2 g of triethylene glycol butyl methyl ether, 4 g of butyl benzoate, and 4 g of dimethyl phthalate. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) filter with a pore size of 0.2 μm to obtain charge transport varnish A1.

[0346] [Chemical formula 47]

[0347]

[0348] [Example 2-2] Preparation of Charge Transport Varnish B1

[0349] At room temperature, 165 mg of fluorene derivative B and 0.198 g of aryl sulfonate A were stirred and dissolved in a mixed solvent of 2 g of triethylene glycol butyl methyl ether, 4 g of butyl benzoate, and 4 g of dimethyl phthalate. The resulting solution was filtered through a PTFE filter with a pore size of 0.2 μm to obtain charge transport varnish B1.

[0350] [Example 2-3] Preparation of Charge Transport Varnish C1

[0351] At room temperature, 173 mg of fluorene derivative C and 0.190 g of aryl sulfonate A were stirred and dissolved in a mixed solvent of 2 g of triethylene glycol butyl methyl ether, 4 g of butyl benzoate, and 4 g of dimethyl phthalate. The resulting solution was filtered through a PTFE filter with a pore size of 0.2 μm to obtain charge transport varnish C1.

[0352] [Example 2-4] Preparation of Charge Transport Varnish D1

[0353] At room temperature, 165 mg of fluorene derivative D and 0.198 g of aryl sulfonate A were stirred and dissolved in a mixed solvent of 2 g of triethylene glycol butyl methyl ether, 4 g of butyl benzoate, and 4 g of dimethyl phthalate. The resulting solution was filtered through a PTFE filter with a pore size of 0.2 μm to obtain charge transport varnish D1.

[0354] [Example 2-5] Preparation of Charge Transport Varnish E1

[0355] At room temperature, 166 mg of fluorene derivative E and 0.197 g of aryl sulfonate A were stirred and dissolved in a mixed solvent of 2 g of triethylene glycol butyl methyl ether, 4 g of butyl benzoate, and 4 g of dimethyl phthalate. The resulting solution was filtered through a PTFE filter with a pore size of 0.2 μm to obtain charge transport varnish E1.

[0356] [Example 2-6] Preparation of Charge Transport Varnish F1

[0357] At room temperature, fluorene derivative F (175 mg) and aryl sulfonate A (0.188 g) were stirred and dissolved in a mixed solvent of triethylene glycol butyl methyl ether (2 g), butyl benzoate (4 g), and dimethyl phthalate (4 g). The resulting solution was filtered through a PTFE filter with a pore size of 0.2 μm to obtain charge transport varnish F1.

[0358] [Example 2-7] Preparation of Charge Transport Varnish A2

[0359] At room temperature, fluorene derivative A (363 mg) was stirred and dissolved in a mixed solvent of triethylene glycol butyl methyl ether (2 g), butyl benzoate (4 g), and dimethyl phthalate (4 g). The resulting solution was filtered through a PTFE filter with a pore size of 0.2 μm to obtain charge transport varnish A2.

[0360] [Examples 2-8 to 2-12] Preparation of Charge Transport Varnishes B2, C2, E2, and F2

[0361] Except that fluorene derivative A was changed to fluorene derivatives B, C, E, and F respectively, charge transport varnishes B2, C2, E2, and F2 were obtained in the same manner as in Example 2-7.

[0362] [3] Evaluation of Refractive Index (n) and Extinction Coefficient (k)

[0363] [Examples 3-1 to 3-5]

[0364] For charge transport varnishes A1, B1, C1, E1, and F1, they were respectively coated on a quartz substrate using a spin coater, pre-fired at 120 °C for 1 minute in an air atmosphere, and then, main-fired at 200 °C for 15 minutes in an air atmosphere to form a uniform 50-nm-thick film on the quartz substrate.

[0365] Using the obtained quartz substrate with the film, the average refractive index n in the visible region and the average extinction coefficient k in the visible region at wavelengths from 400 to 800 nm were measured. The results are shown in Table 1.

[0366] [Table 1]

[0367] Charge-transporting varnish n k Example 3-1 A1 1.686 0.022 Example 3-2 B1 1.685 0.028 Example 3-3 C1 1.693 0.004 Example 3-4 E1 1.685 0.022 Example 3-5 F1 1.698 0.026

[0368] As shown in Table 1, the refractive index of the charge transport film of the present invention is a high value of 1.65 or more, and the extinction coefficient is a low value of 0.03 or less.

[0369] [4] Fabrication and Characterization of Single-Hole Devices (HOD)-1

[0370] In the following examples, as the ITO substrate, the following substrate was used: a 25 mm × 25 mm × 0.7 t glass substrate with ITO patterned on the surface with a film thickness of 150 nm. Before use, impurities on the surface were removed using an O 2 plasma cleaning device (150 W, 30 seconds).

[0371] [Preparation of Hole Injection Layer Solution]

[0372] 0.137 g of an aniline derivative represented by the following formula (S1) synthesized according to the method described in International Publication No. 2013 / 084664 and 0.271 g of an arylsulfonic acid represented by the formula (S2) synthesized according to the method described in International Publication No. 2006 / 025342 were dissolved in 6.7 g of 1,3-dimethyl-2-imidazolidinone under a nitrogen atmosphere. 10 g of cyclohexanol and 3.3 g of propylene glycol were sequentially added to the resulting solution and stirred to prepare a hole injection layer solution.

[0373] [Chemical Formula 48]

[0374]

[0375] [Example 4-1]

[0376] For the above hole injection layer solution, after coating on the ITO substrate using a spin coater, pre-baking was carried out at 80 °C on a hot plate for 1 minute in an atmospheric atmosphere, and then main baking was carried out at 230 °C for 15 minutes to form a hole injection layer (film thickness 30 nm). Next, for the charge-transporting varnish A2, after coating on the hole injection layer using a spin coater, the solvent was removed by vacuum drying at room temperature, and baking was carried out at 130 °C for 10 minutes in an atmospheric atmosphere to form a hole-transporting layer with a film thickness of 40 nm. On top of it, using an evaporation device (vacuum degree 1.0 × 10 -5 Pa), an 80-nm aluminum thin film was formed at a rate of 0.2 nm / second to fabricate a single-hole device (HOD).

[0377] [Examples 4-2 to 4-5]

[0378] Except that the charge-transporting varnish A2 was replaced with charge-transporting varnishes B2, C2, E2, or F2, HODs were fabricated in the same manner as in Example 4-1.

[0379] For each of the HODs fabricated in Examples 4-1 to 4-5, the current density at a driving voltage of 4 V was measured. The results are shown in Table 2.

[0380] [Table 2]

[0381]

[0382] As shown in Table 2, the film made of the charge transporting varnish of the present invention shows good charge transportability.

[0383] [5] Fabrication of single layer device (SLD)

[0384] [Example 5-1]

[0385] For the charge transporting varnish A1, after coating on the ITO substrate using a spin coater, pre-firing was carried out at 120 °C for 1 minute in an atmospheric atmosphere, and then, main firing was carried out at 200 °C for 15 minutes to form a hole injection layer (film thickness 50 nm). On top of it, an aluminum thin film with a film thickness of 80 nm was formed at 0.2 nm / second using an evaporation apparatus (vacuum degree 1.0×10 -5 Pa) to fabricate a single layer device (SLD).

[0386] [Examples 5-2 to 5-6]

[0387] An SLD was fabricated in the same manner as in Example 5-1, except that the charge transporting varnish B1, C1, D1, E1 or F1 was used instead of the charge transporting varnish A1.

[0388] For each SLD fabricated in Examples 5-1 to 5-6, the current density at a driving voltage of 4 V was measured. The results are shown in Table 3.

[0389] [Table 3]

[0390]

[0391] As shown in Table 3, the film made of the charge transporting varnish of the present invention shows good charge transportability.

[0392] [6] Fabrication and evaluation of HOD.2

[0393] [Example 6.1]

[0394] For the charge transporting varnish A1, after coating on the ITO substrate using a spin coater, pre-firing was carried out at 120 °C for 1 minute in an atmospheric atmosphere, and then, main firing was carried out at 200 °C for 15 minutes to form a 50 nm film on the ITO substrate. On top of it, a film of a-NPD and aluminum was sequentially laminated using an evaporation apparatus (vacuum degree 2.0×lO- S pa) to fabricate HOD. The evaporation was carried out under the condition of an evaporation rate of 0.2 nm / second. The film thicknesses of the a-NPD and aluminum films were 30 nm and 80 nm, respectively.

[0395]

Examples 6-2 to 6-5

[0396] Except for using charge transporting varnish Bl, Cl, El, or Fl in place of charge transporting varnish A1, HOD was fabricated in the same manner as in Example 6-1.

[0397] For the HODs fabricated in Examples 6-1 to 6-5, the current density at a driving voltage of 4 V was measured. The results are shown in Table 4.

[0398] [Table 4]

[0399]

[0400] As shown in Table 4, the films made from the charge transporting varnish of the present invention exhibited good charge transport properties.

[0401] [7] Fabrication and Characterization of Organic EL Devices

[0402] [Example 7-1]

[0403] After coating charge transporting varnish A1 on an ITO substrate using a spin coater, pre-baking was performed at 120 °C for 1 minute in an air atmosphere, and then main baking was performed at 200 °C for 15 minutes to form a 50-nm-thick film on the ITO substrate.

[0404] Next, for the ITO substrate on which the film was formed, using an evaporation apparatus (vacuum degree: 1.0×10 -5 Pa), a 30-nm-thick α-NPD film was formed at a rate of 0.2 nm / second. Next, a 10-nm-thick film of the electron blocking material HTEB-01 manufactured by Kanto Chemical Co., Inc. was formed. Next, the host material NS60 for the light-emitting layer and the dopant material Ir(ppy) 3 for the light-emitting layer were co-evaporated. For the co-evaporation, the evaporation rate was controlled so that the concentration of Ir(ppy) 3 became 6%, and a 40-nm-thick layer was stacked. Next, films of Alq 3 , lithium fluoride, and aluminum were sequentially stacked to fabricate an organic EL device. At this time, regarding the evaporation rate, for Alq 3 and aluminum, it was performed under the condition of 0.2 nm / second, and for lithium fluoride, it was performed under the condition of 0.02 nm / second. The film thicknesses were 20 nm, 0.5 nm, and 80 nm, respectively.

[0405] It should be noted that in order to prevent deterioration of characteristics caused by the influence of oxygen, water, etc. in the air, the organic EL element was sealed with a sealing substrate, and its characteristics were evaluated. The sealing was carried out according to the following steps. The organic EL element was placed between the sealing substrates in a nitrogen atmosphere with an oxygen concentration of 2 ppm or less and a dew point of -76°C or less, and the sealing substrates were pasted with an adhesive (manufactured by MORESCO CORPORATION, MORESCO MOISTURE CUT WB90US(P)). At this time, a water scavenger (HD-071010W-40 manufactured by Dainippon Ink and Chemicals, Incorporated) was placed in the sealing substrate together with the organic EL element. For the pasted sealing substrates, UV light (wavelength: 365 nm, irradiation dose: 6000 mJ / cm 2 ) was irradiated, and then annealed at 80°C for 1 hour to cure the adhesive.

[0406] [Examples 7-2 to 7-5]

[0407] An organic EL element was fabricated in the same manner as in Example 7-1, except that charge transport varnish B1, C1, E1, or F1 was used instead of charge transport varnish A1.

[0408] For the obtained organic EL element, the driving voltage, current density, current efficiency, luminous efficiency, external luminous quantum yield (EQE), and LT90 (the time required to reduce the initial luminance by 10% of 5000 cd / m 2 ) were measured during light emission. The results are shown in Table 5. 2

[0409] [Table 5]

[0410]

[0411] As shown in Table 5, the organic EL elements of the present invention all exhibited high current efficiency and high EQE, and showed good lifetime characteristics.

Claims

1. A fluorene derivative represented by the following formula (1): [Chemical formula 1] wherein, Z 1 and Z 2 each independently represents a group represented by the following formula (2) or (3); [Chemical formula 2] In the formula, the dotted line is a bonding end, Ar 1 and Ar 2 each independently represents a phenyl group, a 1-naphthyl group, a 2-naphthyl group, or a group represented by the following formulas (T1-1) to (T1-2), (T4-1) to (T4-2); Ar 3 and Ar 4 each independently represents a group represented by any one of the following formulas (8-5) to (8-6), (10-3) to (10-4): [Chemical formula 3] In the formula, the dotted line is a bonding end.

2. The fluorene derivative according to claim 1, wherein, Ar 1 and Ar 2 are the same group.

3. The fluorene derivative according to claim 1, wherein, Z 1 and Z 2 is a group represented by formula (2).

4. A charge transporting material comprising the fluorene derivative according to any one of claims 1 to 3.

5. A charge transporting varnish comprising the charge transporting material according to claim 4 and an organic solvent.

6. The charge transporting varnish according to claim 5, further comprising a dopant.

7. A charge transporting film obtained from the charge transporting varnish according to claim 5 or 6.

8. An organic electroluminescent element comprising the charge transporting film according to claim 7.

9. The organic electroluminescent element according to claim 8, wherein, the charge transporting film is a hole injection layer or a hole transport layer.

10. A method for manufacturing a fluorene derivative represented by the following formula (1), which comprises: a step of reacting a compound represented by formula (15) with a compound represented by formula (16-1) and a compound represented by formula (16-2) to obtain an intermediate represented by formula (17); a step of reducing the intermediate represented by formula (17) to obtain an intermediate represented by formula (18); and a step of reacting the intermediate represented by formula (18) with a halide represented by formula (19-1) and a halide represented by formula (19-2), [Chemical formula 11] In the formula, Z 1 and Z 2 each independently represents a group represented by the following formula (2) or (3); [Chemical formula 12] In the formula, the dotted line is a bonding end, Ar 1 and Ar 2 each independently represents a phenyl group, a 1-naphthyl group, a 2-naphthyl group, or a group represented by the following formulas (T1-1) to (T1-2), (T4-1) to (T4-2); Ar 3 and Ar 4 each independently represents a group represented by any one of the following formulas (8-5) to (8-6), (10-3) to (10-4); [Chemical formula 13] In the formula, the dotted line is a bonding end, X is a halogen atom or a pseudohalogen group, and the pseudohalogen group is methanesulfonyloxy, fluoroalkylsulfonyloxy, or aromatic sulfonyloxy.

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