Iridium complex compound

Abstract

An iridium complex compound represented by formula (5). Provided is an iridium complex compound which is useful as a material for a light-emitting layer of an organic electroluminescent element, has a reduced half-width of the emission spectrum, has high solubility in a solvent, has a short wavelength without being too long, and is suitable as a red light-emitting material. In formula (5), Ir represents an iridium atom, and X represents a bidentate ligand. And m represents an integer of 1-3. And each of R1-R22 independently represents a hydrogen atom or a substituent. The groups adjacent to each other may further bond to each other to form a ring. And at least one of R13, R17, R18 and R22 represents a substituent other than a hydrogen atom. # imgabs0 #

Description

[0001] This application is a divisional application of the invention patent application with Chinese application number 202080008778.0 (the invention name of the original application is "Iridium coordination compound", and the application date of the original application is January 8, 2020) Technical Field

[0002] The present invention relates to an iridium complex, and more particularly to an iridium complex useful as a material for a light-emitting layer of an organic electroluminescent element (hereinafter sometimes referred to as "organic EL element"). Background Art

[0003] Organic electroluminescent elements are manufactured by stacking multiple layers such as a light-emitting layer, a charge injection layer, and a charge transport layer. At present, many organic electroluminescent elements are manufactured by evaporating organic materials under vacuum. In the vacuum evaporation method, the evaporation process is complicated and the productivity is poor. The organic electroluminescent element manufactured by the vacuum evaporation method is extremely difficult to realize the large-scale panel of the lighting or display. Therefore, in recent years, as a process for efficiently manufacturing an organic electroluminescent element that can be used for large-scale displays or lighting, a wet film forming method (coating method) is being actively studied.

[0004] In order to manufacture an organic electroluminescent element by a wet film-forming method, the material used needs to be a material that is dissolved in an organic solvent and used in the form of ink. When the solvent solubility of the material used is poor, operations such as heating for a long time are required, so there is a possibility that the material will deteriorate before use. If the material used cannot maintain a uniform state for a long time in the solution state, the material will precipitate from the solution, and film formation using an inkjet device or the like will not be possible.

[0005] Materials used in the wet film-forming method are required to have solubility in two senses: to dissolve quickly in an organic solvent and to maintain a uniform state without precipitation after dissolution.

[0006] In recent years, in order to extend the driving life of the element or optimize the optical design of the element to effectively show the so-called microcavity effect to improve color purity, the demand for forming a thicker light-emitting layer has been increasing. In order to form a thick light-emitting layer, it is necessary to increase the concentration of the ink. Therefore, a light-emitting material with higher solvent solubility than before is required.

[0007] In organic EL displays, in addition to long drive life, wide color gamut, i.e., high color reproduction rate, it is also required to achieve high luminous efficiency. In particular, it is required that the red region has a fairly deep red color with an x ​​coordinate of 0.68 in the XYZ color coordinates of the CIE (International Commission on Illumination). In order to display deep red, it is necessary to set the luminous maximum wavelength of the luminescent material to a longer wavelength (e.g., more than 620nm). In this wavelength region, a law known as the energy gap law plays a dominant role. In this wavelength region, the ratio of excitation energy dissipated to molecular motion, i.e., heat energy, becomes larger as the wavelength is extended. Therefore, the luminous quantum yield on the long wavelength side is significantly deteriorated. Therefore, in the red region, it is difficult to simultaneously achieve deep red and luminous quantum yield (cd / A) high efficiency.

[0008] Human visibility also significantly decreases in the red region as the wavelength becomes longer. Therefore, in the deep red region, a higher luminous intensity is required.

[0009] As a stacked structure of an organic EL display, there are two types of structures that differ in the direction in which light is extracted.

[0010] The bottom emission method, which has a relatively simple manufacturing process, is a method of extracting light from organic molecules from below the TFT substrate side, but has a disadvantage that the light utilization efficiency of organic molecules is low.

[0011] In contrast, the top emission method extracts light from above the sealing glass without pixel circuits, etc., so the emitted light can be efficiently extracted to the outside. However, when the top emission method is used, light other than the specific wavelength is reflected and offset in the stacked structure, so it has the property of being difficult to emit outside the stacked structure. Therefore, when the half width of the luminescent spectrum of the luminescent material is wide, light other than the specific wavelength is difficult to emit outside the stacked structure, resulting in a decrease in the efficiency of luminescence.

[0012] As described above, the red coloring material is required to have high solubility in a solvent, high luminous efficiency even when the wavelength is long, and a narrow half width of the luminescent spectrum.

[0013] As a red light emitting material, an iridium complex utilizing phosphorescence that is inherently efficient has been used. In particular, an iridium complex having a phenyl-quinoline type ligand as disclosed in Patent Documents 1 and 2 is widely used.

[0014] Patent Document 1 discloses compounds such as those of structural formulas A1 to A58 in which a ligand having fluorene and quinoline is coordinated to two iridium atoms.

[0015] Patent Document 2 discloses compounds such as Compound Nos. 12 and 189 in which a ligand containing quinoline and fluorene having an aromatic group is coordinated to two iridium atoms.

[0016] Patent Document 1: Japanese Patent Application Publication No. 2006-151888

[0017] Patent Document 2: Japanese Patent Application Publication No. 2009-173630

[0018] The iridium complex with fluorene structure such as patent document 1 is mainly LC luminescence with little participation of iridium atoms. Due to the migration in the ligand, the difference between the electric dipole moment of the excited state and the ground state is small. Therefore, it is generally possible to reduce the half width. On the other hand, fluorene is a rigid structure, so the solubility is greatly impaired. In addition, the participation with the d orbital of iridium is small, and as a result, there is a problem of reduced luminous efficiency.

[0019] For example, compound No. 12 in Patent Document 2 has insufficient solubility and insufficient half-width. A ligand containing quinoline and fluorene having a phenyl group, such as compound No. 6 in Patent Document 2, has a certain effect on the half-width problem and also has a certain effect on the quantum yield. However, if such a ligand is used, the maximum wavelength of luminescence becomes longer, which poses a problem as a red luminescent material. Summary of the invention

[0020] The object of the present invention is to provide an iridium coordination compound which has a narrowed half width of the luminescence spectrum, high solubility in solvents, luminescence efficiency equal to or better than that of conventional materials, and a luminescence maximum wavelength which is not too long, and is suitable as a red luminescent material.

[0021] The present inventors have found that an iridium coordination compound having a specific chemical structure as a red light-emitting material has a light emission maximum wavelength that is not too long, exhibits extremely high solvent solubility compared to conventional materials, and exhibits a high PL quantum yield and a narrow half-width.

[0022] The present invention is an iridium complex shown below.

[0023] [1] An iridium complex represented by the following formula (5).

[0024]

[0025] In formula (5), Ir represents an iridium atom.

[0026] R 1 ~R 12 Each independently represents a hydrogen atom or a substituent.

[0027] R adjacent to each other 1 ~R 12 They may further bond to each other to form a ring.

[0028] R 13 ~R 22Each independently represents a hydrogen atom or a substituent.

[0029] R adjacent to each other 13 ~R 22 They may further bond to each other to form a ring.

[0030] X represents a bidentate ligand.

[0031] m represents an integer of 1-3.

[0032] R 13 , R 17 , R 18 and R 22 At least one of them is a substituent other than a hydrogen atom.

[0033] [2] The iridium complex according to [1], wherein the formula (5) is represented by the following formula (2).

[0034]

[0035] In formula (2), R 1 ~R 22 With R in formula (5) 1 ~R 22 Same meaning.

[0036] [3] The iridium coordination compound according to [1] or [2], wherein R 1 ~R 12 , R 13 ~R 22 The following groups.

[0037] R 1 ~R 12Each is independently selected from D, F, Cl, Br, I, -N(R')2, -CN, -NO2, -OH, -COOR', -C(=O)R', -C(=O)NR', ​​-P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 2 to 30 carbon atoms or a cyclic alkenyl group, a linear, branched or cyclic alkynyl group having 2 to 30 carbon atoms, an aromatic group having 5 to 60 carbon atoms, a heteroaromatic group having 5 to 60 carbon atoms, an aryloxy group having 5 to 40 carbon atoms, an arylthio group having 5 to 40 carbon atoms, an aralkyl group having 5 to 60 carbon atoms, a heteroaralkyl group having 5 to 60 carbon atoms, a diarylamino group having 10 to 40 carbon atoms, an arylheteroarylamino group having 10 to 40 carbon atoms, or a diheteroarylamino group having 10 to 40 carbon atoms.

[0038] The alkyl, alkoxy, alkylthio, alkenyl and alkynyl groups may be further substituted with one or more R's. One -CH2- group or two or more non-adjacent -CH2- groups in these groups may be substituted with -C(-R')=C(-R')-, -C≡C-, -Si(-R')2, -C(=O)-, -NR'-, -O-, -S-, -CONR'- or a divalent aromatic group. One or more hydrogen atoms in these groups may be substituted with D, F, Cl, Br, I or -CN.

[0039] The aromatic group, the heteroaromatic group, the aryloxy group, the arylthio group, the arylalkyl group, the heteroarylalkyl group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group may each independently be further substituted by one or more R′.

[0040] R adjacent to each other 1 ~R 12 They may further bond to each other to form a ring.

[0041] R' is independently selected from a hydrogen atom, D, F, Cl, Br, I, -N(R")2, -CN, -NO2, -Si(R")3, -B(OR")2, -C(=O)R", -P(=O)(R")2, -S(=O)2R", -OSO2R", a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms, A linear, branched or cyclic alkynyl group having 2 to 30 carbon atoms, an aromatic group having 5 to 60 carbon atoms, a heteroaromatic group having 5 to 60 carbon atoms, an aryloxy group having 5 to 40 carbon atoms, an arylthio group having 5 to 40 carbon atoms, an aralkyl group having 5 to 60 carbon atoms, a heteroaralkyl group having 5 to 60 carbon atoms, a diarylamino group having 10 to 40 carbon atoms, an arylheteroarylamino group having 10 to 40 carbon atoms, or a diheteroarylamino group having 10 to 40 carbon atoms.

[0042] The alkyl group, the alkoxy group, the alkylthio group, the alkenyl group and the alkynyl group may be further substituted by one or more R". One -CH2- group or two or more non-adjacent -CH2- groups in these groups may be substituted by -C(-R")=C(-R")-, -C≡C, -Si(-R")2-, -C(=O)-, -NR"-, -O-, -S-, -CONR"- or a divalent aromatic group. One or more hydrogen atoms in these groups may be substituted by D, F, Cl, Br, I or -CN.

[0043] The aromatic group, the heteroaromatic group, the aryloxy group, the arylthio group, the arylalkyl group, the heteroarylalkyl group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group may be further substituted by one or more R″.

[0044] Two or more adjacent R's may be bonded to each other to form an aliphatic, aromatic or heteroaromatic monocyclic or condensed ring.

[0045] R" is independently selected from a hydrogen atom, D, F, -CN, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic group having 3 to 20 carbon atoms, or a heteroaromatic group having 1 to 20 carbon atoms.

[0046] Two or more adjacent R"s may be bonded to each other to form an aliphatic, aromatic or heteroaromatic monocyclic or condensed ring.

[0047] R 13 ~R 22Each independently represents a hydrogen atom or any of the substituents represented by R'.

[0048] [4] The iridium coordination compound according to [1] or [3], wherein in the formula (5), two or more adjacent R 1 ~R 10 , R 11 With R 12 , 2 or more adjacent R 13 ~R 17 or two or more adjacent R 18 ~R 22 They are bonded to each other to form an aliphatic, aromatic or heteroaromatic single ring or condensed ring.

[0049] [5] The iridium complex according to [1], [3] or [4], wherein the formula (5) is represented by the following formula (6).

[0050]

[0051] In formula (6), R 1 ~R 22 , m and R in formula (5) 1 ~R 22 , m have the same meaning.

[0052] R 23 and R 25 Each is independently selected from -N(R')2, -COOR', -C(=O)R', -C(=O)NR', ​​-P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms, The invention further comprises a linear, branched or cyclic alkynyl group having 30 or less carbon atoms, an aromatic group having 5 or more and 60 or less carbon atoms, a heteroaromatic group having 5 or more and 60 carbon atoms, an aryloxy group having 5 or more and 40 carbon atoms, an arylthio group having 5 or more and 40 carbon atoms, an aralkyl group having 5 or more and 60 carbon atoms, a heteroaralkyl group having 5 or more and 60 carbon atoms, a diarylamino group having 10 or more and 40 carbon atoms, an arylheteroarylamino group having 10 or more and 40 carbon atoms, or a diheteroarylamino group having 10 or more and 40 carbon atoms.

[0053] R 24A hydrogen atom, D, -N(R')2, -COOR'-, -C(=O)R', -C(=O)NR', ​​-P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms, The present invention further comprises a linear, branched or cyclic alkynyl group having at least 5 but no more than 30 carbon atoms, an aromatic group having at least 5 but no more than 60 carbon atoms, a heteroaromatic group having at least 5 but no more than 60 carbon atoms, an aryloxy group having at least 5 but no more than 40 carbon atoms, an arylthio group having at least 5 but no more than 40 carbon atoms, an aralkyl group having at least 5 but no more than 60 carbon atoms, a heteroaralkyl group having at least 5 but no more than 60 carbon atoms, a diarylamino group having at least 10 but no more than 40 carbon atoms, an arylheteroarylamino group having at least 10 but no more than 40 carbon atoms, or a diheteroarylamino group having at least 10 but no more than 40 carbon atoms.

[0054] Two or more adjacent R 23 ~R 25 They may be bonded to each other to form an aliphatic, aromatic or heteroaromatic single ring or condensed ring.

[0055] The alkyl, alkoxy, alkylthio, alkenyl and alkynyl groups may be further substituted with one or more R's. One -CH2- group or two or more non-adjacent -CH2- groups in these groups may be substituted with -C(-R')=C(-R')-, -C≡C-, -Si(-R')2, -C(=O)-, -NR'-, -O-, -S-, -CONR'- or a divalent aromatic group. One or more hydrogen atoms in these groups may be substituted with D, F, Cl, Br, I or -CN.

[0056] The aromatic group, the heteroaromatic group, the aryloxy group, the arylthio group, the arylalkyl group, the heteroarylalkyl group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group may each independently be further substituted by one or more R′.

[0057] R 23 ~R 25 When R' is present, R' is the same as R' in formula (5).

[0058] [6] The iridium complex according to any one of [1] to [5], wherein R in formula (2), formula (5) or formula (6) 1 ~R 4 and R 13 ~R 22At least one of the groups contains an alkyl group having 4 to 30 carbon atoms or an aralkyl group having 5 to 30 carbon atoms.

[0059] [7] The iridium complex according to any one of [1] to [6], wherein the substituent R in formula (2), formula (5) or formula (6) is 13 , R 17 , R 18 and R 22 At least one of the groups is an alkyl group having 1 to 4 carbon atoms or an aromatic ring group which may have a substituent.

[0060] [8] The iridium coordination compound according to [7], wherein the substituent R in formula (2), formula (5) or formula (6) is 18 and R 22 Each of them is an alkyl group having 1 to 4 carbon atoms.

[0061] [9] The iridium complex according to any one of [1] to [8], wherein the substituent R in formula (2), formula (5) or formula (6) is 14 , R 15 , R 16 , R 19 , R 20 and R 21 At least one of the groups is an alkyl group, an aromatic ring group which may have a substituent, or an aralkyl group.

[0062]

[10] The iridium coordination compound according to [9], wherein the substituent R in formula (2), formula (5) or formula (6) is 14 , R 15 , R 16 , R 19 , R 20 and R 21 At least one of them is a substituted aromatic ring group, and the substituent is an aralkyl group.

[0063]

[11] The iridium complex according to

[10] , represented by the following formula (3).

[0064]

[0065]

[12] The iridium coordination compound according to any one of [1] to

[10] , wherein the substituent R in formula (2), formula (5) or formula (6) is 13 , R 17 , R 18 and R 22 At least one of them is a substituted aromatic ring group, and the substituent is an aralkyl group.

[0066]

[13] The iridium complex according to

[12] , represented by the following formula (4).

[0067]

[0068] The wavy line in formula (4) indicates a mixture of rotational isomers.

[0069] According to the present invention, an iridium coordination compound suitable as a red light-emitting material can be provided which has a narrowed half width of the emission spectrum, high solubility in solvents, luminous efficiency equal to or better than that of conventional materials, and a light emission maximum wavelength that is not too long. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is a cross-sectional view schematically showing an example of the structure of the organic electroluminescent element of the present invention.

[0071] Figure 2 This is a graph showing the relationship between the half width and the emission maximum wavelength of Compounds 1 to 3, Reference Compounds 1 to 6, and Comparative Compounds 1 to 3.

[0072] Figure 3 This is a graph showing the relationship between the PL quantum yield and the emission maximum wavelength of Compounds 1 to 3, Reference Compounds 1 to 6, and Comparative Compounds 1 to 3. DETAILED DESCRIPTION

[0073] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments and can be implemented with various modifications within the scope of the gist of the invention.

[0074] In the present specification, "aromatic ring" refers to "aromatic hydrocarbon ring" and is distinguished from "heteroaromatic ring" containing heteroatoms as ring-constituting atoms. Similarly, "aromatic group" refers to "aromatic hydrocarbon ring group" and "heteroaromatic group" refers to "heteroaromatic ring group".

[0075] [Iridium coordination compounds]

[0076] The iridium complex of the present invention is a compound represented by the following formula (1), the following formula (2), the formula (5) or the formula (6) described later.

[0077]

[0078] In formula (1), Ir represents an iridium atom. 1 and Ar 2 represents an aromatic ring or a heteroaromatic ring which may be substituted. 1 ~R 12 Each independently represents a hydrogen atom or a substituent, and adjacent substituents may be further bonded to each other to form a ring.

[0079]

[0080] In formula (5), Ir represents an iridium atom.

[0081] R 1 ~R 12 Each independently represents a hydrogen atom or a substituent.

[0082] R adjacent to each other 1 ~R 12 They may further bond to each other to form a ring.

[0083] R 13 ~R 22 Each independently represents a hydrogen atom or a substituent.

[0084] R adjacent to each other 13 ~R 22 They may further bond to each other to form a ring.

[0085] X represents a bidentate ligand.

[0086] m represents an integer of 1-3.

[0087] R 13 , R 17 , R 18 and R 22 At least one of them is a substituent other than a hydrogen atom.

[0088] A more preferred embodiment of the compound represented by formula (1) is a compound represented by the following formula (2):

[0089]

[0090] R 1 ~R 12 Compared with R in formula (1) and formula (5), 1 ~R 12 Same meaning.

[0091] R 13 ~R 22 With R in formula (5) 13 ~R 22 Same meaning.

[0092] The reason why the iridium complex of the present invention as a red light emitting material has a light emission maximum wavelength that is not too long and has extremely high solvent solubility compared to conventional materials while having a light emission efficiency and a narrow half width comparable to conventional materials can be presumed as follows.

[0093] Fluorene in formula (1), formula (2) or formula (5) has high electron-donating ability due to the electron-donating property of methylene and the influence of the rigidly fixed π conjugated plane. It works by increasing the HOMO of the ligand and suppressing the inflow of d electrons from the iridium atom. Therefore, the MLCT property is reduced and the LC property is improved. The LC luminescence with less participation of iridium atoms is small due to the migration in the ligand, and the difference between the electric dipole moment of the excited state and the ground state is small, so the half width can be reduced.

[0094] However, as the participation of the d orbital decreases, the phosphorescence emission rate constant kr of the luminescent material decreases, resulting in a decrease in luminescence efficiency (see Chapter 4 of Selected Books on Complex Chemistry 2: Photochemistry of Metal Complexes, edited by Yoichi Sasaki and Osamu Ishitani, Sankyo Publishing (2007)).

[0095] By making a tricyclic metallated homoligand (L3Ir) in which all three ligands in trivalent iridium are identical, the half width (Formula (1), Formula (2)) can be reduced. In addition, even if it is also a tricyclic metallated complex, it will not be as different as the heteroligand (L3Ir) in which the ligands for iridium are different. 1 2L 2 Ir, L 1 L 2 2Ir or L 1 L 2 L 3 Ir) different ligands affect each other, so from this point of view, the quantum yield tends to be good. On the other hand, as mentioned above, from the aspect of the reduced participation of the d orbital, there is also a side of the quantum yield reduction.

[0096] The present inventors have found that in a fluorene 3-coordinated iridium complex, by introducing appropriate substituents at specific positions of the quinoline ring, the quantum yield can be improved without damaging the preferred characteristics of the narrow half width of fluorene. That is, it was found that by simultaneously introducing aromatic ring groups at the 4-position and 6-position of the quinoline ring, the conjugation of the ligand is extended and the LUMO of the ligand is lowered, thereby increasing the proportion of iridium excited from the d orbital and restoring the quantum yield.

[0097] In addition, by introducing an aromatic ring group at the 4-position and the 6-position of the quinoline ring, the molecular size becomes larger, and thus the number of possible spatial conformations between the quinoline and aromatic ring groups increases. Therefore, crystallization is less likely to occur, and as a result, solubility is also increased. Here, regarding the introduction of an aromatic ring group into the quinoline ring portion, it is considered that one is not sufficient, and it is important to place the aromatic ring group at the 4-position and the 6-position, respectively.

[0098] On the other hand, even in the case of a tricyclometallated homopolymerized Ir complex in which all three ligands in trivalent iridium are identical, as in formula (1), formula (2), and formula (5) where m=3, the half width is slightly widened by interaction between the identical three ligands. Therefore, it is believed that the half width can be further reduced by forming a bicyclometallated complex by making at least one of the three ligands a ligand that is difficult to interact with the other two ligands, as in formula (5) where m=1 or 2.

[0099] In addition, by R in formula (2) or formula (5) 13 , R 17 , R 18 and R 22 At least one of the substituents is other than a hydrogen atom, which can form a torsion between the quinoline ring and the benzene ring bonded to the quinoline ring, shorten the conjugation length, improve the solubility, and inhibit the long wavelength, thereby forming a compound whose luminescent maximum wavelength is not too long and is suitable as a red light-emitting material.

[0100] <Ar 1 and Ar 2 >

[0101] Ar 1 and Ar 2 represents an aromatic ring or a heteroaromatic ring, which may be the same or different from each other. These rings may further have a substituent, and the type of the substituent is the same as that of R described below. 13 ~R 22 Same meaning.

[0102] From the viewpoint of solubility and the maximum wavelength of emission due to conjugation extension, the composition of Ar 1 or Ar 2 The number of carbon atoms in the moiety is usually 4 to 60, preferably 4 to 40, and more preferably 5 to 20, excluding the number of carbon atoms in the substituent.

[0103] As Ar 1 or Ar 2 Specific examples of the aromatic ring include a monocyclic benzene ring; a bicyclic naphthalene ring; a tricyclic or more fluorene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring, Among the heteroaromatic rings, there can be mentioned furan ring, benzofuran ring, dibenzofuran ring containing oxygen atoms; thiophene ring, benzothiophene ring, dibenzothiophene ring containing sulfur atoms; pyrrole ring, pyrazole ring, imidazole ring, benzimidazole ring, indole ring, indazole ring, carbazole ring, indolocarbazole ring, indenocarbazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, phthalazine ring, quinoxaline ring, quinazoline ring, quinazolinone ring, acridine ring, phenanthridine ring, carboline ring, purine ring containing nitrogen atoms; Azole ring, Oxadiazole ring, isocyanate Azole ring, benzyl isocyanate azole ring, thiazole ring, benzothiazole ring, isothiazole ring, benzisothiazole ring and the like.

[0104] From the viewpoint of solubility and the maximum wavelength of emission based on conjugation extension, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, and an isoquinoline ring are preferred; a benzene ring, a naphthalene ring, a phenanthrene ring, and a pyridine ring are more preferred; and a benzene ring is most preferred.

[0105] <R 1 ~R 12 >

[0106] R in formula (1), formula (5) and formula (2) 1 ~R 12 represents a hydrogen atom or a substituent. 1 ~R 12 They are independent of each other and can be the same or different.

[0107] Two or more adjacent R 1 ~R 12 They may be bonded to each other to form an aliphatic, aromatic or heteroaromatic single ring or condensed ring.

[0108] In R 1 ~R 12 In the case of a substituent other than a hydrogen atom, its type is not particularly limited, and the best substituent can be selected considering the precise control of the target luminous wavelength, the compatibility with the solvent used, the compatibility with the host compound when the organic electroluminescent element is made, etc. When they are optimized, the preferred substituent is the range described below.

[0109] R 1 ~R 12Each is independently selected from D, F, Cl, Br, I, -N(R')2, -CN, -NO2, -OH, -COOR', -C(=O)R', -C(=O)NR', ​​-P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 2 to 30 carbon atoms or a cyclic alkenyl group, a linear, branched or cyclic alkynyl group having 2 to 30 carbon atoms, an aromatic group having 5 to 60 carbon atoms, a heteroaromatic group having 5 to 60 carbon atoms, an aryloxy group having 5 to 40 carbon atoms, an arylthio group having 5 to 40 carbon atoms, an aralkyl group having 5 to 60 carbon atoms, a heteroaralkyl group having 5 to 60 carbon atoms, a diarylamino group having 10 to 40 carbon atoms, an arylheteroarylamino group having 10 to 40 carbon atoms, or a diheteroarylamino group having 10 to 40 carbon atoms.

[0110] The alkyl, alkoxy, alkylthio, alkenyl and alkynyl groups may be further substituted with one or more R's, and one -CH2- group or two or more non-adjacent -CH2- groups in these groups may be substituted with -C(-R')=C(-R')-, -C≡C-, -Si(-R')2, -C(=O)-, -NR'-, -O-, -S-, -CONR'- or a divalent aromatic group. In addition, one or more hydrogen atoms in these groups may be substituted with D, F, Cl, Br, I or -CN.

[0111] The aromatic group, the heteroaromatic group, the aryloxy group, the arylthio group, the arylalkyl group, the heteroarylalkyl group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group may each independently be further substituted by one or more R' groups.

[0112] R' will be described later.

[0113] <R 1 ~R 12 Preferred example>

[0114] As can be used as R 1 ~R 12Examples of the linear, branched or cyclic alkyl group having 1 to 30 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, isopropyl, isobutyl, cyclopentyl, cyclohexyl, n-octyl, norbornyl, adamantyl, etc. From the viewpoint of durability, the number of carbon atoms is preferably 1 or more, and preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

[0115] As can be used as R 1 ~R 12 Examples of the linear, branched or cyclic alkoxy group having a carbon number of 1 or more and 30 or less include methoxy, ethoxy, n-propoxy, n-butoxy, n-hexyloxy, isopropoxy, cyclohexyloxy, 2-ethoxyethoxy, 2-ethoxyethoxyethoxy, etc. From the viewpoint of durability, the carbon number is preferably 1 or more, and preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

[0116] As can be used as R 1 ~R 12 Examples of the linear, branched or cyclic alkylthio group having a carbon number of 1 or more and 30 or less include methylthio, ethylthio, n-propylthio, n-butylthio, n-hexylthio, isopropylthio, cyclohexylthio, 2-methylbutylthio, n-hexylthio, etc. From the viewpoint of durability, the carbon number is preferably 1 or more, and preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

[0117] As can be used as R 1 ~R 12 Examples of straight chain, branched or cyclic alkenyl groups having a carbon number of 2 or more and 30 or less include vinyl, allyl, propenyl, heptenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl, etc. From the viewpoint of durability, the carbon number is preferably 2 or more, and preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

[0118] As can be used as R 1 ~R 12 Examples of straight chain, branched or cyclic alkynyl groups having a carbon number of 2 or more and 30 or less include ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, etc. From the viewpoint of durability, the carbon number is preferably 2 or more, and preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

[0119] Can be used as R 1 ~R 12The aromatic group having 5 to 60 carbon atoms and the heteroaromatic group having 3 to 60 carbon atoms may exist in the form of a single ring or a condensed ring, or may be a group formed by further bonding or condensing other types of aromatic groups or heteroaromatic groups to one ring.

[0120] Examples of these groups include phenyl, naphthyl, anthracenyl, benzanthryl, phenanthrenyl, triphenylenyl, pyrenyl, yl, fluoranthene, peryl, benzopyrenyl, benzofluoranthene, tetraphenyl, pentacene, biphenyl, terphenyl, fluorenyl, spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, indenofluorenyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, dibenzothienyl, pyrrolyl, indolyl, isoindolyl, carbazolyl, benzocarbazolyl, indolocarbazolyl, indenocarbazolyl, pyridinyl, cinnolinyl, isocinolinyl, acridinyl, phenanthridinyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthoimidazolyl, phenanthroimidazolyl, pyridinimidazolyl, Azolyl, benzo Azolyl, naphthoxy oxazolyl, thiazolyl, benzothiazolyl, pyrimidinyl, benzopyrimidinyl, pyridazinyl, quinoxalinyl, diazaanthryl, diazapyrenyl, pyrazinyl, phenanthroline oxazine, phenothiazine, naphthyridinyl, azacarbazolyl, benzocarboline, phenanthroline, triazine, 2,6-diphenyl-1,3,5-triazine-4-yl, and the like.

[0121] From the viewpoint of the balance between solubility and durability, the number of carbon atoms of these groups is preferably 5 or more, and is preferably 50 or less, more preferably 40 or less, and most preferably 30 or less.

[0122] The aromatic hydrocarbon group is preferably a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, Preferably, it is a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a spirobifluorenyl group, or an indenofluorenyl group, and more preferably, it is a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a fluorenyl group, or an indenofluorenyl group.

[0123] Preferred heteroaromatic groups include furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, dibenzothienyl, pyrrolyl, indolyl, isoindolyl, carbazolyl, benzocarbazolyl, indolocarbazolyl, indenocarbazolyl, pyridyl, cinnolinyl, isocinnolinyl, acridinyl, phenanthridinyl, phenothiazinyl, phenanthrid ... azine, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthioimidazolyl, pyridinimidazolyl, Azolyl, benzo Azolyl, naphthoxy The oxazolyl group, thiazolyl group, benzothiazolyl group, pyrimidinyl group, benzopyrimidinyl group, pyridazinyl group, quinoxalinyl group, diazaanthryl group, diazapyrenyl group, pyrazinyl group, naphthyridinyl group, azacarbazolyl group, benzocarbolinyl group, phenanthrolinyl group, triazinyl group, 2,6-diphenyl-1,3,5-triazine-4-yl group, more preferably dibenzofuranyl group, dibenzothienyl group, carbazolyl group, benzocarbazolyl group, indolocarbazolyl group, indenocarbazolyl group, pyridinyl group, cinnolinyl group, isocinnolinyl group, acridinyl group, phenothiazinyl group, phenanthrolinyl group oxazinyl, pyrazolyl, indazolyl, benzimidazolyl, pyridinimidazolyl, benzoxazolyl, benzothiazolyl, pyrimidinyl, benzopyrimidinyl, pyridazinyl, quinoxalinyl, pyrazinyl, naphthyridinyl, triazinyl, 2,6-diphenyl-1,3,5-triazin-4-yl.

[0124] As can be used as R 1 ~R 12 Examples of aryloxy groups having a carbon number of 5 or more and 40 or less include phenoxy, methylphenoxy, naphthoxy, methoxyphenoxy, etc. From the viewpoint of the balance between solubility and durability, the carbon number of these aryloxy groups is preferably 5 or more, and preferably 30 or less, more preferably 25 or less, and most preferably 20 or less.

[0125] As can be used as R 1 ~R 12 Examples of arylthio groups having a carbon number of 5 or more and 40 or less include phenylthio, methylphenylthio, naphthylthio, methoxyphenylthio, etc. From the viewpoint of the balance between solubility and durability, the carbon number of these arylthio groups is preferably 5 or more, and preferably 30 or less, more preferably 25 or less, and most preferably 20 or less.

[0126] As can be used as R 1 ~R 12 Examples of the aralkyl group having 5 or more and 60 or less carbon atoms include 1,1-dimethyl-1-phenylmethyl, 1,1-di(n-butyl)-1-phenylmethyl, 1,1-di(n-hexyl)-1-phenylmethyl, 1,1-di(n-octyl)-1-phenylmethyl, phenylmethyl, phenylethyl, 3-phenyl-1-propyl, 4-phenyl-1-n-butyl, 1-methyl-1-phenylethyl, 5-phenyl-1-n-propyl, 6-phenyl-1-n-hexyl, 6-naphthyl-1-n-hexyl, 7-phenyl-1-n-heptyl, 8-phenyl-1-n-octyl, and 4-phenylcyclohexyl. From the viewpoint of the balance between solubility and durability, the number of carbon atoms of these aralkyl groups is preferably 5 or more, and more preferably 40 or less.

[0127] As can be used as R 1 ~R 12Examples of heteroarylalkyl groups having 5 to 60 carbon atoms include 1,1-dimethyl-1-(2-pyridyl)methyl, 1,1-di(n-hexyl)-1-(2-pyridyl)methyl, (2-pyridyl)methyl, (2-pyridyl)ethyl, 3-(2-pyridyl)-1-propyl, 4-(2-pyridyl)-1-n-butyl, 1-methyl-1-(2-pyridyl)methyl, 4-(2-pyridyl)-1-n-octyl, 4-(2-pyridyl)-cyclohexyl, etc. In terms of the balance between solubility and durability, the number of carbon atoms in these heteroarylalkyl groups is preferably 5 or more, and is preferably 50 or less, more preferably 40 or less, and most preferably 30 or less.

[0128] As can be used as R 1 ~R 12 Examples of diarylamino groups having a carbon number of 10 or more and 40 or less include diphenylamino, phenyl(naphthyl)amino, di(biphenyl)amino, di(p-terphenyl)amino, etc. From the viewpoint of the balance between solubility and durability, the carbon number of these diarylamino groups is preferably 10 or more, and preferably 36 or less, more preferably 30 or less, and most preferably 25 or less.

[0129] As can be used as R 1 ~R 12 Examples of arylheteroarylamino groups having 10 or more and 40 or less carbon atoms include phenyl(2-pyridyl)amino and phenyl(2,6-diphenyl-1,3,5-triazine-4-yl)amino groups. From the viewpoint of the balance between solubility and durability, the number of carbon atoms in these arylheteroarylamino groups is preferably 10 or more, and preferably 36 or less, more preferably 30 or less, and most preferably 25 or less.

[0130] As can be used as R 1 ~R 12 Examples of the diheteroarylamino group having a carbon number of 10 or more and 40 or less include di(2-pyridyl)amino and di(2,6-diphenyl-1,3,5-triazine-4-yl)amino groups. From the viewpoint of the balance between solubility and durability, the carbon number of these diheteroarylamino groups is preferably 10 or more, and preferably 36 or less, more preferably 30 or less, and most preferably 25 or less.

[0131] As R 1 ~R 12, especially from the viewpoint of not damaging the durability of the organic electroluminescent element as a light-emitting material, each independently preferably is a hydrogen atom, F, -CN, a straight-chain, branched or cyclic alkyl group having 1 to 30 carbon atoms, an aryloxy group having 5 to 40 carbon atoms, an arylthio group having 5 to 40 carbon atoms, a diarylamino group having 10 to 40 carbon atoms, an aralkyl group having 5 to 60 carbon atoms, an aromatic group having 5 to 60 carbon atoms, or a heteroaromatic group having 5 to 60 carbon atoms, and particularly preferably is a hydrogen atom, F, -CN, an alkyl group, an aralkyl group, an aromatic group or a heteroaromatic group, and most preferably is a hydrogen atom, F, -CN, an alkyl group, an aromatic group or a heteroaromatic group.

[0132] Two or more adjacent R in formula (1) and formula (2) 1 ~R 12 The ligands may be bonded to each other to form a ring. However, if the fused ring structure becomes large, the rigidity of the ligand may increase excessively, which may impair the solubility. Therefore, the fused ring structure may not be formed.

[0133] Two or more adjacent R in formula (5) 1 ~R 12 They may be bonded to each other to form a ring, especially selected from R 1 ~R 10 Two or more adjacent substituents in 11 With R 12 They may be bonded to each other to form aliphatic, aromatic or heteroaromatic monocyclic or condensed rings. However, if the condensed ring structure becomes larger, the rigidity of the ligand increases excessively, which may impair the solubility. Therefore, the condensed ring structure may not be formed.

[0134] <R'>

[0135] R' is independently selected from a hydrogen atom, D, F, Cl, Br, I, -N(R")2, -CN, -NO2, -Si(R")3, -B(OR")2, -C(=O)R", -P(=O)(R")2, -S(=O)2R", -OSO2R", a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms, and a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms. , a straight-chain, branched or cyclic alkynyl group having 2 to 30 carbon atoms, an aromatic group having 5 to 60 carbon atoms, a heteroaromatic group having 5 to 60 carbon atoms, an aryloxy group having 5 to 40 carbon atoms, an arylthio group having 5 to 40 carbon atoms, an aralkyl group having 5 to 60 carbon atoms, a heteroaralkyl group having 5 to 60 carbon atoms, a diarylamino group having 10 to 40 carbon atoms, an arylheteroarylamino group having 10 to 40 carbon atoms, or a diheteroarylamino group having 10 to 40 carbon atoms.

[0136] The alkyl group, the alkoxy group, the alkylthio group, the alkenyl group and the alkynyl group may be further substituted with one or more R", and one -CH2- group or two or more non-adjacent -CH2- groups in these groups may be substituted with -C(-R")=C(-R")-, -C≡C, -Si(-R")2-, -C(=O)-, -NR"-, -O-, -S-, -CONR"- or a divalent aromatic group. In addition, one or more hydrogen atoms in these groups may be substituted with D, F, Cl, Br, I or -CN.

[0137] The aromatic group, the heteroaromatic group, the aryloxy group, the arylthio group, the arylalkyl group, the heteroarylalkyl group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group may be further substituted by one or more R″.

[0138] Two or more adjacent R's may be bonded to each other to form aliphatic, aromatic or heteroaromatic monocyclic or condensed rings. R's may be bonded to each other to form a ring, but if the condensed ring structure becomes larger, the rigidity of the ligand increases excessively, which may sometimes impair solubility, so a condensed ring structure may not be formed.

[0139] Examples of the above groups that can be used as R' are the same as those mentioned above for R 1 ~R 12 That is, for each group that can be used as R', the above R 1 ~R 12 Examples and preferred ranges of substituents of the same structure as described in the items.

[0140] <R”>

[0141] R" is independently selected from a hydrogen atom, D, F, -CN, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic group having 3 to 20 carbon atoms, or a heteroaromatic group having 1 to 20 carbon atoms.

[0142] Two or more adjacent R"s may bond to each other to form aliphatic, aromatic or heteroaromatic monocyclic or condensed rings. However, if R"s bond to each other to form a ring and the condensed ring structure becomes larger, the rigidity of the ligand increases excessively, which sometimes impairs the solubility, so it is not necessary to form a condensed ring structure.

[0143] <Preferred example of R>

[0144] As an aliphatic hydrocarbon group having 1 to 20 carbon atoms which can be used as R", for example, R 1 ~R 12 The same applies to the preferred range of the linear, branched or cyclic alkyl group having 1 to 20 carbon atoms.

[0145] As the aromatic group having 3 or more and 20 or less carbon atoms which can be used as R", for example, R 1 ~R 12 The same applies to the aromatic group having 3 to 20 carbon atoms in the aromatic group described in the item.

[0146] As the heteroaromatic group having 1 to 20 carbon atoms which can be used as R", for example, R 1 ~R 12 The same applies to the preferred range of the heteroaromatic group having 1 to 20 carbon atoms.

[0147] <R 13 ~R 22 >

[0148] R 13 ~R 22 represents a hydrogen atom or a substituent. 13 ~R 22 When it is a substituent, the type of the substituent and its preferred range are the same as those of R' above. 13 ~R 22 Each independently is the same as R'.

[0149] Similar to R', two or more adjacent R 13 ~R 22 In this case, it is obvious that two or more adjacent substituents can be bonded to each other to form a ring selected from R13 ~R 17 Two or more adjacent substituents in 18 ~R 22 If the condensed ring structure becomes larger, the rigidity of the ligand increases excessively, which may impair the solubility. Therefore, the condensed ring structure may not be formed.

[0150] The three ligands in formula (1) and (2) may be the same or different.

[0151] <Preferred Ar 1 ,Ar 2 , R 1 ~R 4 , R 13 ~R 22 The state of >

[0152] In order to improve the solubility without adversely affecting the luminous efficiency and half width, a further preferred embodiment is that Ar in formula (1) 1 ,Ar 2 Or the components R in formula (1), formula (2) and formula (5) 1 ~R 4 In the atomic group of Ar, there is at least one linear, branched or cyclic alkyl group having 4 to 30 carbon atoms, or an aralkyl group having 5 to 30 carbon atoms. It is particularly preferred that at least one of these groups is included in at least Ar. 1 ,Ar 2 By setting these groups, the solubility in the solvent can be improved. 1 ~R 4 By providing these groups in the fluorene, it is possible to prevent oxidation of the fluorene side, which would hinder the entry of electrons and thus reduce the quantum yield, and to increase the solubility in the solvent.

[0153] Furthermore, in order to improve solubility and suppress the elongation of the maximum wavelength of luminescence, it is preferred that R in formula (5) 13 , R 17 , R 18 and R 22 At least one of them is a substituent other than a hydrogen atom.

[0154] In formula (2) and formula (5), in order to improve solubility without adversely affecting luminous efficiency and half width and suppress the influence of the luminescent maximum wavelength due to the introduction of substituents, a further preferred embodiment is R 13 , R 17 , R 18 and R 22 At least one of them is an aromatic ring group which may have an alkyl group having 1 to 4 carbon atoms or a substituent.13 , R 17 , R 18 and R 22 , in which case the aromatic ring group which may have a substituent is an aromatic group having 5 or more and 60 or less carbon atoms which may be substituted by R". By introducing these groups as needed, the solubility can be improved, and further, since the bond between the quinoline ring and the aromatic ring having the substituent is twisted, the conjugation of fluorene and quinoline will not extend before the aromatic groups arranged at the 4-position and 6-position of quinoline, thereby shortening the conjugation length and preventing the wavelength from being longer than necessary.

[0155] In formula (5), R is particularly preferred 18 and R 22 At least one of the groups is an alkyl group having 1 to 4 carbon atoms or an aromatic ring group which may have a substituent.

[0156] The substituent R in formula (2) and formula (5) 1 ~R 4 and R 13 ~R 22 A structure in which at least one of the groups is an alkyl group having 4 to 30 carbon atoms or an aralkyl group having 5 to 30 carbon atoms is considered to be preferred because it can improve the solubility in a solvent without causing electronic influence on fluorene.

[0157] The substituent R in formula (2) and formula (5) 13 , R 17 , R 18 and R 22 In the structure where at least one of the substituents is an alkyl group, steric hindrance is generated between the benzene ring bonded to the quinoline ring and the quinoline ring, and the bond is twisted, so that conjugation can be stopped, and the wavelength is suppressed beyond the necessary length. As a result, it is believed that the quantum yield can be improved (it is known that in the case of a long wavelength, according to the energy gap law, the quantum yield decreases, and the quantum yield of the short wavelength side becomes higher). As a substituent, an alkyl group having 1 to 4 carbon atoms or an aromatic ring group that may have a substituent is particularly preferred.

[0158] Furthermore, the substituent R in formula (2), formula (5) or formula (6) is 18 and R 22 Preferably, they are alkyl groups having 1 to 4 carbon atoms. 18 and R 22 All of them are alkyl groups having 1 to 4 carbon atoms, and sufficient twisting can be formed between the quinoline ring and the benzene ring bonded to the quinoline ring, thereby more sufficiently suppressing the increase in wavelength.

[0159] Furthermore, the substituent R in formula (2) and formula (5) 14 , R 15 , R 16 , R19 , R 20 and R 21 At least one of them is an alkyl group, an aromatic ring group which may have a substituent, or an aralkyl group, so that R 13 , R 17 , R 18 and R 22 At least one of the tips is twisted by a substituent such as an alkyl group, that is, the benzene ring that is twistedly bonded to the quinoline ring improves the solubility in the solvent, so it is preferred that the wavelength is prevented from being longer than necessary, the PL yield is improved, and the solubility in the solvent is improved. It is particularly preferred to be a substituted aromatic ring group, and the substituent is more preferably an aralkyl group. The structure is R 14 , R 15 and R 16 At least one of them is an alkyl group, an aromatic ring group which may have a substituent, or an aralkyl group, and R 13 and R 17 At least one of them has a substituent such as an alkyl group, or R 19 , R 20 and R 21 At least one of them is an alkyl group, an aromatic ring group which may have a substituent, or an aralkyl group, and R 18 and R 22 In the case where at least one of the groups has a substituent such as an alkyl group.

[0160] In addition, for the substituent R in formula (2) and formula (5), 13 , R 17 , R 18 and R 22 The substituents such as alkyl groups may further substitute the aromatic ring group or the aralkyl group. In this way, a substituent that produces a twist and a structure that improves solubility can be provided in the same substituent.

[0161] <Specific examples>

[0162] The following describes preferred specific examples of the iridium complex of the present invention other than those described in the Examples below, with respect to the case where m=3 in Formula (1), Formula (2), and Formula (5). The iridium complex of the present invention is not limited to the following exemplary compounds.

[0163]

[0164] Specific examples of further preferred aspects are shown below.

[0165]

[0166] Specific examples of further preferred aspects are shown below.

[0167]

[0168] From the viewpoint of improving quantum yield and suppressing the increase in wavelength, among the above compounds shown as specific examples, the one corresponding to R is particularly preferred. 13 , R 17 , R 18 and R 22 A compound wherein at least one of the groups is a substituent other than a hydrogen atom.

[0169] As the iridium complex of the present invention, a compound represented by the following formula (3) is particularly preferred.

[0170]

[0171] In addition, as the iridium complex of the present invention, a compound represented by the following formula (4) is preferred.

[0172]

[0173] The wavy line in formula (4) indicates a mixture of rotational isomers.

[0174] [Iridium complex represented by formula (5) or formula (6)]

[0175] A preferred embodiment of the iridium complex represented by the formula (5) is a compound represented by the following formula (6) in which X is represented by the following formula (6a).

[0176]

[0177] In formula (6), R 1 ~R 22 , m and R in formula (5) 1 ~R 22 , m have the same meaning.

[0178] In formula (6) and formula (6a), R 23 and R 25Each is independently selected from -N(R')2, -COOR', -C(=O)R', -C(=O)NR', ​​-P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms, The invention further comprises a linear, branched or cyclic alkynyl group having 30 or less carbon atoms, an aromatic group having 5 or more and 60 or less carbon atoms, a heteroaromatic group having 5 or more and 60 carbon atoms, an aryloxy group having 5 or more and 40 carbon atoms, an arylthio group having 5 or more and 40 carbon atoms, an aralkyl group having 5 or more and 60 carbon atoms, a heteroaralkyl group having 5 or more and 60 carbon atoms, a diarylamino group having 10 or more and 40 carbon atoms, an arylheteroarylamino group having 10 or more and 40 carbon atoms, or a diheteroarylamino group having 10 or more and 40 carbon atoms.

[0179] R 24 A hydrogen atom, D, -N(R')2, -COOR'-, -C(=O)R', -C(=O)NR', ​​-P(=O)(R')2, -S(=O)R', -S(=O)2R', -OS(=O)2R', a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms, a linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms, The present invention further comprises a linear, branched or cyclic alkynyl group having at least 5 but no more than 30 carbon atoms, an aromatic group having at least 5 but no more than 60 carbon atoms, a heteroaromatic group having at least 5 but no more than 60 carbon atoms, an aryloxy group having at least 5 but no more than 40 carbon atoms, an arylthio group having at least 5 but no more than 40 carbon atoms, an aralkyl group having at least 5 but no more than 60 carbon atoms, a heteroaralkyl group having at least 5 but no more than 60 carbon atoms, a diarylamino group having at least 10 but no more than 40 carbon atoms, an arylheteroarylamino group having at least 10 but no more than 40 carbon atoms, or a diheteroarylamino group having at least 10 but no more than 40 carbon atoms.

[0180] Two or more adjacent R 23 ~R 25 They may be bonded to each other to form an aliphatic, aromatic or heteroaromatic single ring or condensed ring.

[0181] The alkyl, alkoxy, alkylthio, alkenyl and alkynyl groups may be further substituted with one or more R's, and one -CH2- group or two or more non-adjacent -CH2- groups in these groups may be substituted with -C(-R')=C(-R')-, -C≡C-, -Si(-R')2, -C(=O)-, -NR'-, -O-, -S-, -CONR'- or a divalent aromatic group. In addition, one or more hydrogen atoms in these groups may be substituted with D, F, Cl, Br, I or -CN.

[0182] The aromatic group, the heteroaromatic group, the aryloxy group, the arylthio group, the arylalkyl group, the heteroarylalkyl group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group may each independently be further substituted by one or more R′.

[0183] R 23 ~R 25 When R' is present, R' is the same as R' in formula (5).

[0184] In the present invention, from the viewpoint of reducing the half width, it is more preferred that only one of the three ligands is a ligand represented by formula (6a), that is, m=2 in formula (6).

[0185] <R 23 , R 25 >

[0186] R 23 , R 25 With R in formula (5) 23 , R 25 Similarly, when R" is present, R" is the same as R" in formula (5).

[0187] R 23 , R 25 The specific examples, preferred ranges, and preferred forms of the above groups are the same as those of R in formula (5). 1 ~R 12 The specific examples, preferred ranges, and preferred aspects shown in the items are the same.

[0188] As R 23 , R 25 From the viewpoint of durability, the above-mentioned alkyl group, the above-mentioned aromatic group, the above-mentioned heteroaromatic group, the above-mentioned aralkyl group or the above-mentioned heteroaralkyl group are each independently preferred, and the above-mentioned alkyl group or the above-mentioned aralkyl group is more preferred.

[0189] <R 24 >

[0190] About R 24 Specific examples, preferred ranges, and preferred embodiments of the above groups, and R 1~R 12 The specific examples, preferred ranges, and preferred aspects shown in the items are the same.

[0191] As R 24 From the viewpoint of durability, the above-mentioned hydrogen atom, the above-mentioned alkyl group, the above-mentioned aromatic group, the above-mentioned heteroaromatic group, the above-mentioned aralkyl group or the above-mentioned heteroaralkyl group are each independently preferred, and the above-mentioned hydrogen atom or the above-mentioned alkyl group is more preferred.

[0192] Two or more adjacent R in formula (6) 23 ~R 25 They may be bonded to each other to form an aliphatic, aromatic or heteroaromatic single ring or condensed ring.

[0193] In R 23 ~R 25 When they are bonded to each other to form a condensed ring, examples of the condensed ring include an aliphatic ring or a condensed ring thereof such as hexahydro-1,8(2H,5H)naphthalenedione and 1,3-cyclodecanedione, and an aromatic and aliphatic condensed ring such as 2-acetyl-3,4-dihydro-1(2H)-naphthalenone.

[0194] From the viewpoint of durability, an aliphatic condensed ring is preferred.

[0195] In the formula (5) and the formula (6), m is an integer of 1 to 3, and preferably 2 to 3 from the viewpoint of durability.

[0196] In formula (5) or formula (6), R 1 ~R 10 Two or more adjacent substituents, R 11 With R 12 , selected from R 13 ~R 17 Two or more adjacent substituents in or selected from R 18 ~R 22 In the above-mentioned, two or more adjacent substituents can be bonded to each other to form aliphatic or aromatic or heteroaromatic monocyclic or condensed rings. However, if the condensed ring structure becomes larger, the rigidity of the ligand increases excessively, which sometimes impairs solubility, so it is also possible not to form a condensed ring structure.

[0197] In formula (5) and formula (6), when m is 2 or more, R 1～12 , R 13～22 The ligands may be the same or different.

[0198] In formula (5) and formula (6), when m is 1, the two ligands X in formula (5) and the two ligands (-OC(R 23 )=C(R 24 )C(R25 )=O-) can be the same or different.

[0199] In the formula (5), when m=3, the iridium complex represented by the formula (5) is substantially the same as the iridium complex represented by the formula (2).

[0200] <Specific examples of iridium complexes represented by formula (5) and formula (6)>

[0201] Preferred specific examples of the iridium complex of the present invention represented by formula (5) and formula (6) other than those shown in the Examples described below are shown below. The iridium complex of the present invention is not limited to the following exemplary compounds.

[0202]

[0203] <Emission Maximum Wavelength>

[0204] Iridium complex of the present invention can make luminous wavelength suitably be long wavelength.As the index of the length representing luminous wavelength, the maximum luminous wavelength measured by the step shown below is preferably more than 615nm, more preferably more than 620nm.In addition, be preferably below 650nm, more preferably below 640nm, more preferably below 635nm.By being these scopes, there is the trend that can show the preferred color of the red light emitting material suitable as organic electroluminescent element.

[0205] (Method for determining the maximum emission wavelength)

[0206] At room temperature, the concentration of 1×10 －4 The solution containing the iridium complex was dissolved in 10 mol / L or less, and the phosphorescence spectrum was measured using a spectrophotometer (organic EL quantum yield measuring device C9920-02 manufactured by Hamamatsu Photonics Co., Ltd.). The wavelength showing the maximum value of the obtained phosphorescence spectrum intensity was regarded as the maximum emission wavelength of the present invention, that is, the emission maximum wavelength.

[0207] <Synthesis method of iridium coordination compound>

[0208] <Method for Synthesizing Ligand>

[0209] The ligand of the iridium coordination compound of the present invention can be synthesized by a combination of known methods. The fluorene ring can be easily introduced by using, for example, a compound having a bromine, -B(OH)2 group, an acetyl group or a carboxyl group at the 2-position of the fluorene ring as a raw material. The synthesis of the fluorene-quinoline ligand can be synthesized by subjecting these raw materials to further Suzuki-Miyaura coupling reaction with halogenated quinolines, or Friedlaender cyclization reaction with 2-formyl or acylanilides or acyl-aminopyridines located at ortho positions (Chem. Rev. 2009, 109, 2562 or Organic Reaction), 28 (2), 37-201) and other known reactions.

[0210] <Synthesis Method of Iridium Coordination Compound>

[0211] The iridium complex of the present invention can be synthesized by a combination of known methods, etc. This will be described in detail below.

[0212] Regarding the synthesis method of iridium coordination compounds, the following methods can be exemplified: for easy understanding, the method of cross-linking an iridium binuclear complex via chlorine as shown in the following formula [A] using a phenylpyridine ligand as an example (MG Colombo, T.C Brunold, T. Riedener, HU Gudel, Inorg. Chem. 1994, 33, 545-550); the method of further cross-linking the binuclear complex with chlorine by exchanging it with acetylacetone to obtain the target product after converting it into a mononuclear complex as shown in the following formula [B] (S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, R. Kwong, I. Tsyba, M. Borz, B. Mui, R. Bau, M. Thompson, Inorg. Chem., 2001, 40, 1704-1711), etc., but are not limited to these.

[0213] For example, the conditions of a typical reaction shown in the following formula [A] are as follows. As a first step, a chlorine-crosslinked iridium binuclear complex is synthesized by reacting 2 equivalents of a ligand with 1 equivalent of iridium chloride n-hydrate. A mixed solvent of 2-ethoxyethanol and water is usually used as a solvent, but no solvent or other solvents may also be used. The ligand may also be used in excess, or an additive such as a base may be used to promote the reaction. Other crosslinking anionic ligands such as bromine may also be used instead of chlorine.

[0214] The reaction temperature is not particularly limited, but is usually preferably 0° C. or higher, more preferably 50° C. or higher, and preferably 250° C. or lower, more preferably 150° C. or lower. Within this temperature range, only the target reaction proceeds without byproducts or decomposition reactions, and high selectivity tends to be obtained.

[0215]

[0216] The second step is to add a halogen ion scavenger such as silver trifluoromethanesulfonate to contact the newly added ligand to obtain the target complex. Ethoxyethanol or diethylene glycol dimethyl ether is usually used as the solvent. Depending on the type of ligand, no solvent or other solvents can be used, or a mixture of multiple solvents can be used. Even if a halogen ion scavenger is not added, the reaction sometimes proceeds, so it is not necessarily necessary. In order to increase the reaction yield and selectively synthesize the facial isomer with higher quantum yield, the addition of this scavenger is beneficial. The reaction temperature is not particularly limited and is usually carried out in the range of 0°C to 250°C.

[0217] The typical reaction conditions represented by the following formula [B] are described. The binuclear complex of the first step can be synthesized in the same manner as formula [A]. The second step is to convert the binuclear complex into a mononuclear complex coordinated by a 1,3-diketone ligand by reacting it with 1 equivalent or more of a 1,3-diketone compound such as acetylacetone and 1 equivalent or more of a basic compound such as sodium carbonate that can extract active hydrogen from the 1,3-diketone compound. Solvents such as ethoxyethanol and dichloromethane that can dissolve the raw material binuclear complex are usually used. When the ligand is in liquid form, it can also be carried out without a solvent. The reaction temperature is not particularly limited and is usually carried out in the range of 0°C to 200°C.

[0218]

[0219] In the third step, one or more equivalents of the ligand are reacted. The type and amount of the solvent are not particularly limited. When the ligand is liquid at the reaction temperature, no solvent may be used. The reaction temperature is also not particularly limited. Since the reaction is slightly less reactive, the reaction is usually carried out at a relatively high temperature of 100°C to 300°C. Therefore, it is preferred to use a high boiling point solvent such as glycerol.

[0220] After the final reaction, the product is refined in order to remove unreacted raw materials, reaction by-products and solvents. Refining can be applied to the refining operation in conventional organic synthetic chemistry. As described in the above-mentioned non-patent literature, normal phase silica gel column chromatography is mainly used for refining. The developing solution can use a single solvent or a mixed solution of hexane, heptane, dichloromethane, chloroform, ethyl acetate, toluene, methyl ethyl ketone, methanol. Refining can be performed multiple times by changing the conditions. Other chromatographic techniques (reversed phase silica gel chromatography, size exclusion chromatography, paper chromatography), liquid separation cleaning, re-lining, recrystallization, suspension cleaning of powders, and refining operations such as reduced pressure drying can be implemented as needed.

[0221] <Applications of Iridium Complexes>

[0222] The iridium complex of the present invention can be suitably used as a material used in an organic electroluminescent element, that is, a red light-emitting material of an organic electroluminescent element. The iridium complex of the present invention can be suitably used as a light-emitting material of an organic electroluminescent element, other light-emitting elements, and the like.

[0223] [Composition containing iridium coordination compound]

[0224] The iridium coordination compound of the present invention is preferably used together with a solvent because of its excellent solvent solubility. Hereinafter, a composition containing the iridium coordination compound of the present invention and a solvent (hereinafter sometimes referred to as "the composition of the present invention" or "the composition containing the iridium coordination compound of the present invention") is described.

[0225] The composition containing the iridium coordination compound of the present invention contains the above-mentioned iridium coordination compound of the present invention and a solvent. The composition containing the iridium coordination compound of the present invention is generally used to form a layer or film by a wet film-forming method, and is particularly preferably used to form an organic layer of an organic electroluminescent element. The organic layer is particularly preferably a light-emitting layer.

[0226] The iridium complex-containing composition of the present invention is preferably used as a composition for an organic electroluminescent element, and is particularly preferably used as a composition for forming a light-emitting layer.

[0227] The content of the iridium coordination compound of the present invention in the composition of this iridium coordination compound is usually more than 0.001 mass %, preferably more than 0.01 mass %, usually below 99.9 mass %, preferably below 99 mass %.By making the content of the iridium coordination compound in the composition be the scope, from adjacent layer (for example, hole transport layer, hole blocking layer) to luminescent layer, the injection of hole, electron can be efficiently carried out, driving voltage can be reduced.

[0228] The iridium complex compound of the present invention may contain only one kind or two or more kinds in combination in the iridium complex compound-containing composition.

[0229] When the iridium complex-containing composition of the present invention is used for, for example, an organic electroluminescent device, it may contain, in addition to the above-mentioned iridium complex and solvent, a charge transporting compound used in the organic electroluminescent device, particularly in the light-emitting layer.

[0230] When the iridium complex-containing composition of the present invention is used to form a light-emitting layer of an organic electroluminescent device, it is preferred that the iridium complex of the present invention be contained as a light-emitting material and another charge-transporting compound be contained as a charge-transporting host material.

[0231] The solvent contained in the iridium complex-containing composition of the present invention is a volatile liquid component used to form a layer containing the iridium complex by wet film formation.

[0232] Since the iridium coordination compound of the present invention as a solute has high solvent solubility, the solvent is not particularly limited as long as it is an organic solvent in which the charge transport compound described later is well dissolved. Preferred solvents include, for example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, phenylcyclohexane, and tetralin; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, and trichlorobenzene; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethoxytoluene, Aromatic ethers such as methyl anisole and diphenyl ether; aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; alicyclic ketones such as cyclohexanone, cyclooctanone, and fenchone; alicyclic alcohols such as cyclohexanol and cyclooctanol; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; aliphatic alcohols such as butanol and hexanol; aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA), etc.

[0233] Among them, alkanes and aromatic hydrocarbons are preferred. In particular, phenylcyclohexane has a preferred viscosity and boiling point in a wet film-forming process.

[0234] These solvents may be used alone or in any combination and ratio.

[0235] The boiling point of the solvent used is usually 80° C. or higher, preferably 100° C. or higher, more preferably 120° C. or higher, and is usually 270° C. or lower, preferably 250° C. or lower, more preferably 230° C. or lower. If the boiling point of the solvent is lower than this range, the film formation stability may be reduced due to evaporation of the solvent from the composition during wet film formation.

[0236] The content of the solvent in the composition containing the iridium coordination compound is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, and preferably 99.99% by mass or less, more preferably 99.9% by mass or less, particularly preferably 99% by mass or less. Usually the thickness of the light-emitting layer is about 3nm to 200nm, but if the content of the solvent is less than the lower limit, the viscosity of the composition is too high and the film forming workability is likely to be reduced. If the content of the solvent exceeds the upper limit, the thickness of the film obtained by removing the solvent after film formation cannot be obtained, so there is a tendency to be difficult to form a film.

[0237] As other charge transporting compounds that may be contained in the composition containing the iridium coordination compound of the present invention, charge transporting compounds that have been conventionally used as materials for organic electroluminescent elements may be used. Examples thereof include pyridine, carbazole, naphthalene, perylene, pyrene, anthracene, Tetracene, phenanthrene, coronene, fluoranthene, triphenylene, fluorene, acetyl naphthofluoranthene, coumarin, p-bis(2-phenylvinyl)benzene and its derivatives, quinacridone derivatives, DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminophenylvinyl)-4H-pyran) series compounds, benzopyran derivatives, rhodamine derivatives, benzothioanthene derivatives, azabenzothioanthene, fused aromatic ring compounds substituted with arylamino groups, styryl derivatives substituted with arylamino groups, etc.

[0238] These may be used alone or in any combination and ratio of two or more.

[0239] Relative to 1 mass part of the iridium coordination compound of the present invention in the composition containing the iridium coordination compound, the content of other charge transporting compounds in the composition containing the iridium coordination compound is usually 1000 mass parts or less, preferably 100 mass parts or less, and more preferably 50 mass parts or less, and is usually 0.01 mass part or more, preferably 0.1 mass part or more, and more preferably 1 mass part or more.

[0240] In the composition containing the iridium coordination compound of the present invention, other compounds may be further contained in addition to the above-mentioned compounds etc. as required. For example, in addition to the above-mentioned solvents, other solvents may be contained. As such solvents, for example, amides such as N,N-dimethylformamide and N,N-dimethylacetamide, dimethyl sulfoxide, etc. may be cited. They may be used alone or in any combination and ratio.

[0241] [Organic electroluminescent element]

[0242] The iridium complex of the present invention can be used to produce an organic electroluminescent device (hereinafter sometimes referred to as "the organic electroluminescent device of the present invention"). The organic electroluminescent device of the present invention containing the iridium complex of the present invention is described below.

[0243] The organic electroluminescent device of the present invention preferably comprises at least an anode, a cathode and at least one organic layer between the anode and the cathode on a substrate, and at least one of the organic layers contains the iridium complex of the present invention. The organic layer includes a light-emitting layer.

[0244] The organic layer containing the iridium complex of the present invention is more preferably a layer formed using the composition of the present invention, and is further preferably a layer formed by a wet film-forming method. The layer formed by the wet film-forming method is preferably the light-emitting layer.

[0245] In the present invention, the wet film-forming method refers to a method of forming a film in a wet manner by using, for example, spin coating, dip coating, die coating, rod coating, blade coating, roll coating, spray coating, capillary coating, inkjet, nozzle printing, screen printing, gravure printing, flexographic printing, etc. as a film-forming method, that is, a coating method, and a film formed by these methods is dried to form a film.

[0246] Figure 1 It is a schematic diagram showing a cross section of a preferred structural example of the organic electroluminescent element 10 of the present invention. Figure 1 , symbol 1 represents a substrate, symbol 2 represents an anode, symbol 3 represents a hole injection layer, symbol 4 represents a hole transport layer, symbol 5 represents a light emitting layer, symbol 6 represents a hole blocking layer, symbol 7 represents an electron transport layer, symbol 8 represents an electron injection layer, and symbol 9 represents a cathode.

[0247] The materials applied to these structures can be known materials, without particular limitation, and the representative materials and methods of making each layer are recorded as an example below. In addition, when citing a gazette, a paper, etc., the content can be appropriately adopted and applied within the common sense of those skilled in the art.

[0248] <Substrate 1>

[0249] The substrate 1 is a support of the organic electroluminescent element, and a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, etc. can be generally used. Among these, a glass plate, a plate of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, polysulfone, etc. is preferred. From the aspect that the organic electroluminescent element is not easily deteriorated by the external air, the substrate 1 is preferably a material with high gas barrier properties. Therefore, when a material with low gas barrier properties is used, such as a synthetic resin substrate, it is preferred to provide a dense silicon oxide film on at least one side of the substrate 1 to improve the gas barrier properties.

[0250] <Anode 2>

[0251] The anode 2 has the function of injecting holes into the layer on the light-emitting layer side. The anode 2 is usually composed of a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as indium and / or tin oxide, a metal halide such as copper iodide, a conductive polymer such as carbon black or poly (3-methylthiophene), polypyrrole, polyaniline, etc.

[0252] The formation of the anode 2 is usually carried out by a dry method such as a sputtering method or a vacuum evaporation method. When the anode 2 is formed using metal particles such as silver, particles such as copper iodide, carbon black, conductive metal oxide particles, conductive polymer fine powders, etc., it can also be formed by dispersing them in a suitable binder resin solution and coating them on a substrate. In the case of a conductive polymer, a thin film can be directly formed on a substrate by electrolytic polymerization, or a conductive polymer can be coated on a substrate to form the anode 2 (Appl. Phys. Lett., Vol. 60, p. 2711, 1992).

[0253] The anode 2 is usually a single-layer structure, but may be a laminated structure as appropriate. When the anode 2 is a laminated structure, different conductive materials may be laminated on the first layer of the anode.

[0254] The thickness of the anode 2 can be determined according to the required transparency and material. In particular, when high transparency is required, the thickness at which the transmittance of visible light is preferably 60% or more, and more preferably 80% or more. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

[0255] When transparency is not required, the thickness of the anode 2 may be any thickness depending on the required strength and the like. In this case, the anode 2 may be the same thickness as the substrate 1 .

[0256] When forming a film on the surface of the anode 2, it is preferred to remove impurities on the anode by subjecting the anode to ultraviolet + ozone, oxygen plasma, argon plasma or the like treatment before film formation, and to adjust its ionization potential in advance to improve hole injection properties.

[0257] <Hole injection layer 3>

[0258] The layer that is responsible for transporting holes from the anode 2 side to the light-emitting layer 5 side is generally referred to as a hole injection transport layer or a hole transport layer. When there are two or more layers that are responsible for transporting holes from the anode 2 side to the light-emitting layer 5 side, the layer closer to the anode 2 side is sometimes referred to as a hole injection layer 3. From the perspective of strengthening the function of transporting holes from the anode 2 to the light-emitting layer 5 side, it is preferred to use the hole injection layer 3. When the hole injection layer 3 is used, the hole injection layer 3 is usually formed on the anode 2.

[0259] The film thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and is usually 1000 nm or less, preferably 500 nm or less.

[0260] The hole injection layer 3 may be formed by vacuum deposition or wet film formation. The wet film formation is preferred because of excellent film forming properties.

[0261] The hole injection layer 3 preferably contains a hole transporting compound, more preferably contains a hole transporting compound and an electron accepting compound. The hole injection layer 3 further preferably contains a cation radical compound, particularly preferably contains a cation radical compound and a hole transporting compound.

[0262] (Hole Transporting Compound)

[0263] The hole injection layer forming composition usually contains a hole transport compound that becomes the hole injection layer 3. In the case of a wet film forming method, the hole injection layer forming composition usually further contains a solvent. The hole transport compound in the hole injection layer forming composition preferably has high hole transport and can efficiently transport the injected holes. Therefore, it is preferred that the hole mobility is large and impurities that become traps are not easily generated during manufacture and use. In addition, it is preferred that the stability is excellent, the ionization potential is small, and the transparency to visible light is high. In particular, when the hole injection layer 3 is in contact with the light-emitting layer 5, it is preferred that the compound that does not extinguish the light from the light-emitting layer 5, and the compound that does not form an exciplex with the light-emitting layer 5 to reduce the light emission efficiency.

[0264] As the hole transport compound, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferred from the viewpoint of the charge injection barrier from the anode 2 to the hole injection layer 3. Examples of the hole transport compound include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds formed by connecting a tertiary amine with a fluorene group, hydrazone compounds, silazane compounds, and quinacridone compounds.

[0265] Among the above-mentioned exemplary compounds, aromatic amine compounds are preferred from the viewpoint of amorphousness and visible light transmittance, and aromatic tertiary amine compounds are particularly preferred. Aromatic tertiary amine compounds refer to compounds having an aromatic tertiary amine structure, and also include compounds having a group derived from an aromatic tertiary amine.

[0266] The type of aromatic tertiary amine compound is not particularly limited, but from the perspective of easily obtaining uniform luminescence through the surface smoothing effect, it is preferred to use a polymer compound (polymeric compound connected by repeating units) with a weight average molecular weight of 1000 or more and 1000000 or less. As a preferred example of the aromatic tertiary amine polymer compound, a polymer compound having a repeating unit shown in the following formula (I) can be cited.

[0267]

[0268] In formula (I), Ar 1 and Ar 2Each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. 3 ~Ar 5 Each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. Q represents a linking group selected from the following linking group group. 1 ~Ar 5 In the above formula (A), two groups bonded to the same N atom may bond to each other to form a ring.

[0269] The linking group is shown below.

[0270]

[0271] In the above formulas, Ar 6 ~Ar 16 Each independently represents an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent. a ~R b Each independently represents a hydrogen atom or an arbitrary substituent.

[0272] As Ar 1 ~Ar 16 The aromatic group and heteroaromatic group are preferably groups derived from a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, or a pyridine ring, and more preferably groups derived from a benzene ring or a naphthalene ring, from the perspective of solubility, heat resistance, and hole injection and transport properties of the polymer compound.

[0273] Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by formula (I) include aromatic tertiary amine polymer compounds described in International Publication No. 2005 / 089024.

[0274] (Electron Accepting Compound)

[0275] In order to increase the conductivity of the hole injection layer 3 by oxidation of the hole transport compound, the hole injection layer 3 preferably contains an electron accepting compound.

[0276] The electron accepting compound is preferably a compound having an oxidizing power and the ability to accept one electron from the hole transporting compound. Specifically, the electron accepting compound is preferably a compound having an electron affinity of 4 eV or more, and more preferably a compound having an electron affinity of 5 eV or more.

[0277] Examples of such electron accepting compounds include those selected from triarylboron compounds, metal halides, Lewis acids, organic acids, One or more compounds selected from the group consisting of salts of arylamine and metal halide, and salts of arylamine and Lewis acid. Specifically, 4-isopropyl-4'-methyldiphenyl iodide can be mentioned. Tetrakis(pentafluorophenyl)borate, triphenylsulfonium tetrafluoroborate and other organic group substituted Salts (International Publication No. 2005 / 089024); high-valence inorganic compounds such as iron (III) chloride (Japanese Patent Publication No. 11-251067), ammonium peroxodisulfate, etc.; cyano compounds such as tetracyanoethylene; aromatic boron compounds such as tris(pentafluorophenyl)borane (Japanese Patent Publication No. 2003-31365); fullerene derivatives and iodine, etc.

[0278] (Cationic radical compounds)

[0279] The cationic radical compound is preferably an ionic compound composed of a cationic radical, which is a chemical species obtained by removing one electron from a hole transporting compound, and a counter anion. When the cationic radical is derived from a hole transporting polymer compound, the cationic radical has a structure obtained by removing one electron from a repeating unit of the polymer compound.

[0280] As the cationic radical, a chemical species obtained by removing one electron from the compound described above as the hole transporting compound is preferred. In view of amorphous properties, visible light transmittance, heat resistance and solubility, a chemical species obtained by removing one electron from a compound preferred as the hole transporting compound is preferred.

[0281] The cationic radical compound can be generated by mixing the above-mentioned hole transporting compound and the electron accepting compound. That is, by mixing the above-mentioned hole transporting compound and the electron accepting compound, electron migration occurs from the hole transporting compound to the electron accepting compound, and a cationic ion compound composed of the cationic radical of the hole transporting compound and the counter anion is generated.

[0282] Cationic radical compounds derived from polymer compounds such as PEDOT / PSS (Adv. Mater., 2000, Vol. 12, p. 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, Vol. 94, p. 7716) are also produced by oxidative polymerization (dehydrogenative polymerization).

[0283] The oxidative polymerization referred to herein is chemical or electrochemical oxidation of monomers in an acidic solution using peroxodisulfate, etc. In the case of this oxidative polymerization (dehydrogenation polymerization), a polymer is formed by oxidizing the monomer, and a cationic radical is generated by removing one electron from a repeating unit of the polymer with an anion from the acidic solution as a counter anion.

[0284] (Formation of Hole Injection Layer 3 by Wet Film Formation Method)

[0285] When the hole injection layer 3 is formed by a wet film-forming method, it is usually formed by the following operation: a material to be the hole injection layer 3 is mixed with a solvent (hole injection layer solvent) that can dissolve the material to prepare a composition for film formation (hole injection layer forming composition), and the hole injection layer forming composition is formed on a layer (usually the anode 2) corresponding to the lower layer of the hole injection layer 3 by a wet film-forming method, and then dried. The drying of the formed film can be carried out in the same manner as the drying method in the formation of the light-emitting layer 5 by the wet film-forming method.

[0286] The concentration of the hole transport compound in the hole injection layer forming composition is arbitrary as long as it does not significantly impair the effect of the present invention, but is preferably lower in terms of uniformity of film thickness, and is preferably higher in terms of less likely to cause defects in the hole injection layer 3. Specifically, the concentration of the hole transport compound in the hole injection layer forming composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[0287] Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, and amide solvents.

[0288] Examples of the ether solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); and aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole.

[0289] Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.

[0290] Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene.

[0291] Examples of the amide solvent include N,N-dimethylformamide and N,N-dimethylacetamide.

[0292] Besides these, dimethyl sulfoxide and the like can also be used.

[0293] The hole injection layer 3 is usually formed by a wet film-forming method by preparing a composition for forming a hole injection layer, applying the composition to a layer (usually the anode 2) corresponding to the lower layer of the hole injection layer 3 to form a film, and drying the film. After the hole injection layer 3 is formed, the coated film is usually dried by heating, reduced pressure drying, etc.

[0294] (Formation of Hole Injection Layer 3 by Vacuum Deposition Method)

[0295] When the hole injection layer 3 is formed by vacuum deposition, one or more constituent materials of the hole injection layer 3 (the hole transport compound, electron accepting compound, etc.) are usually placed in a crucible (when two or more materials are used, each is usually placed in a different crucible) provided in a vacuum container, and the vacuum container is evacuated to 100°C by a vacuum pump. －4 After about 100 Pa, the crucible is heated (when two or more materials are used, each crucible is usually heated), and the material in the crucible is evaporated while controlling the evaporation amount (when two or more materials are used, each is usually evaporated while controlling the evaporation amount independently), and a hole injection layer 3 is formed on the anode 2 on the substrate placed opposite to the crucible. When two or more materials are used, their mixture can also be placed in a crucible, heated, and evaporated to form a hole injection layer 3.

[0296] The vacuum degree during vapor deposition is not limited unless the effect of the present invention is significantly impaired, but is usually 0.1×10 － 6 Torr(0.13×10 －4 Pa) and above 9.0×10 －6 Torr(12.0×10 －4 The evaporation rate is not limited as long as it does not significantly impair the effect of the present invention, and is usually / second or more and The film forming temperature during vapor deposition is not limited unless the effects of the present invention are significantly impaired, but is preferably 10° C. to 50° C.

[0297] <Hole transport layer 4>

[0298] The hole transport layer 4 is a layer that is responsible for transporting holes from the anode 2 side to the light-emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescent element of the present invention, but is preferably provided from the perspective of strengthening the function of transporting holes from the anode 2 to the light-emitting layer 5. When the hole transport layer 4 is provided, usually, the hole transport layer 4 is formed between the anode 2 and the light-emitting layer 5. When the hole injection layer 3 is present, the hole transport layer 4 is formed between the hole injection layer 3 and the light-emitting layer 5.

[0299] The film thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[0300] The hole transport layer 4 may be formed by vacuum deposition or wet film formation. The wet film formation is preferred because of excellent film forming properties.

[0301] The hole transport layer 4 usually contains a hole transport compound that becomes the hole transport layer 4. Examples of the hole transport compound contained in the hole transport layer 4 include, in particular, aromatic diamines containing two or more tertiary amines and having two or more fused aromatic rings substituted on the nitrogen atom, represented by 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (Japanese Patent Publication No. 5-234681), aromatic amine compounds having a starburst structure such as 4,4',4"-tris(1-naphthylphenylamino)triphenylamine (J. Lumin., Vol. 72-74, p. 985, 1997), and aromatic amine compounds consisting of a tetramer of triphenylamine (Che m. Commun., 2175 pages, 1996), spiro compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, 91, 209 pages, 1997), carbazole derivatives such as 4,4'-N,N'-dicarbazole biphenyl, etc. In addition, polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Publication No. 7-53953), and polyarylene ether sulfone containing tetraphenylbenzidine (Polym. Adv. Tech., 7, 33 pages, 1996) can also be preferably used.

[0302] (Formation of the Hole Transport Layer 4 by Wet Film Formation Method)

[0303] When the hole transport layer 4 is formed by a wet film forming method, it is usually formed using a hole transport layer forming composition instead of a hole injection layer forming composition, similarly to the case of forming the hole injection layer 3 by a wet film forming method.

[0304] When the hole transport layer 4 is formed by a wet film forming method, the hole transport layer forming composition generally further contains a solvent. The solvent used in the hole transport layer forming composition can be the same as the solvent used in the hole injection layer forming composition described above.

[0305] The concentration of the hole transporting compound in the hole transport layer forming composition may be in the same range as the concentration of the hole transporting compound in the hole injection layer forming composition.

[0306] The hole transport layer 4 can be formed by a wet film formation method in the same manner as the above-mentioned film formation method of the hole injection layer 3 .

[0307] (Formation of Hole Transport Layer 4 by Vacuum Deposition)

[0308] When the hole transport layer 4 is formed by vacuum deposition, it can usually be formed by using the constituent material of the hole transport layer 4 instead of the constituent material of the hole injection layer 3, as in the case of forming the hole injection layer 3 by vacuum deposition. The film formation conditions such as the vacuum degree, deposition rate and temperature during deposition can be the same as those during vacuum deposition of the hole injection layer 3.

[0309] <Luminous layer 5>

[0310] The light-emitting layer 5 is a layer that performs the following functions: when an electric field is applied between a pair of electrodes, the holes injected from the anode 2 are recombined with the electrons injected from the cathode 9 to be excited and emit light. The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 9. When the hole injection layer 3 is provided on the anode 2, the light-emitting layer 5 is formed between the hole injection layer 3 and the cathode 9, and when the hole transport layer 4 is provided on the anode 2, the light-emitting layer 5 is formed between the hole transport layer 4 and the cathode 9.

[0311] The film thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly damage the effect of the present invention. From the perspective of the film being less likely to produce defects, it is preferably thicker. On the other hand, from the perspective of easily forming a low driving voltage, it is preferably thinner. Therefore, the film thickness of the light-emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, preferably 200 nm or less, and more preferably 100 nm or less.

[0312] The light-emitting layer 5 contains at least a material having light-emitting properties (light-emitting material), and preferably contains a material having charge transport properties (charge transporting material). As the light-emitting material, any light-emitting layer may contain the iridium complex of the present invention, and other light-emitting materials may be used as appropriate.

[0313] Next, light-emitting materials other than the iridium complex of the present invention will be described in detail.

[0314] (Luminescent material)

[0315] The luminescent material is not particularly limited as long as it emits light at a desired luminescent wavelength and does not impair the effect of the present invention, and known luminescent materials can be applied. The luminescent material can be a fluorescent luminescent material or a phosphorescent luminescent material, preferably a material with good luminescent efficiency, and preferably a phosphorescent luminescent material from the viewpoint of internal quantum efficiency.

[0316] Examples of the fluorescent material include the following materials.

[0317] Examples of the fluorescent material that emits blue light (blue fluorescent material) include naphthalene, perylene, pyrene, anthracene, coumarin, p-Bis(2-phenylvinyl)benzene and their derivatives, etc.

[0318] Examples of fluorescent materials that provide green light emission (green fluorescent materials) include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Al(C9H6NO)3.

[0319] Examples of the fluorescent material that emits yellow light (yellow fluorescent material) include rubrene and naphthyrimidone derivatives.

[0320] Examples of fluorescent materials that emit red light (red fluorescent materials) include DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminophenylvinyl)-4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioanthene derivatives, and azabenzothioanthene.

[0321] Examples of phosphorescent materials include organic metal complexes containing metals selected from Groups 7 to 11 of the long-period periodic table (hereinafter, unless otherwise specified, "periodic table" means the long-periodic periodic table). Preferred metals selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold, and the like.

[0322] As the ligand of the organometallic complex, a ligand formed by connecting a (hetero)aryl group with pyridine, pyrazole, phenanthroline, etc., such as a (hetero)arylpyridine ligand and a (hetero)arylpyrazole ligand, is preferred, and a phenylpyridine ligand and a phenylpyrazole ligand are particularly preferred. Here, a (hetero)aryl group represents an aryl group or a heteroaryl group.

[0323] Preferred phosphorescent materials include phenylpyridine complexes such as tris(2-phenylpyridine)iridium, tris(2-phenylpyridine)ruthenium, tris(2-phenylpyridine)palladium, bis(2-phenylpyridine)platinum, tris(2-phenylpyridine)osmium, and tris(2-phenylpyridine)rhenium; and porphyrin complexes such as octaethylporphyrin platinum, octaphenylporphyrin platinum, octaethylporphyrin palladium, and octaphenylporphyrin palladium.

[0324] Examples of polymer-based light-emitting materials include polyfluorene-based materials such as poly(9,9-dioctylfluorene-2,7-diyl), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)], and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(1,4-benzo-2{2,1'-3}-triazole)]; and polyphenylenevinylene-based materials such as poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene].

[0325] (Charge transport material)

[0326] The charge transporting material is a material having the property of transporting positive charges (holes) or negative charges (electrons). The charge transporting material is not particularly limited as long as the effects of the present invention are not impaired, and a known material can be used.

[0327] As the charge transport material, a compound conventionally used in the light emitting layer 5 of an organic electroluminescent element can be used, and a compound used as a host material of the light emitting layer 5 is particularly preferred.

[0328] As the charge transport material, specifically, there can be mentioned aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which a tertiary amine is linked with a fluorene group, hydrazone compounds, silazane compounds, silaneamine compounds, phosphoramide compounds, quinacridone compounds, and the like, which are exemplified as the hole transport compound of the hole injection layer 3, and in addition, there can be mentioned anthracene compounds, pyrene compounds, carbazole compounds, pyridine compounds, phenanthroline compounds, Electron transporting compounds such as oxadiazole compounds and silole compounds, etc.

[0329] As the charge transport material, aromatic diamines containing two or more tertiary amines and having two or more fused aromatic rings substituted on the nitrogen atom, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (Japanese Patent Publication No. 5-234681), aromatic amine compounds having a starburst structure such as 4,4',4"-tris(1-naphthylphenylamino)triphenylamine (J. Lumin., Vol. 72-74, p. 985, 1997), and tetramers of triphenylamine can also be preferably used. Aromatic amine compounds (Chem. Commun., p. 2175, 1996), fluorene compounds such as 2,2',7,7'-tetrakis(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, Vol. 91, p. 209, 1997), carbazole compounds such as 4,4'-N,N'-dicarbazolebiphenyl, and the like are the compounds exemplified as the hole transporting compounds of the hole transporting layer 4. In addition, 2-(4-biphenylyl)-5-(p-tert-butylphenyl)-1,3,4- oxadiazole (tBu-PBD), 2,5-bis(1-naphthyl)-1,3,4- BND, etc. oxadiazole compounds, silole compounds such as 2,5-bis(6'-(2',2"-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), phenanthroline compounds such as bathophenanthroline (BPhen) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproin), etc.

[0330] (Formation of Light Emitting Layer 5 by Wet Film Formation Method)

[0331] The light emitting layer 5 may be formed by a vacuum deposition method or a wet film forming method. However, the wet film forming method is preferred because of its excellent film forming properties.

[0332] When the light-emitting layer 5 is formed by a wet film-forming method, it is usually formed by using a light-emitting layer-forming composition prepared by mixing a material to be the light-emitting layer 5 with a solvent (light-emitting layer solvent) that can dissolve the material, instead of the hole injection layer-forming composition, as in the case of forming the hole injection layer 3 by a wet film-forming method. In the present invention, as the light-emitting layer-forming composition, the composition containing the iridium coordination compound of the present invention is preferably used.

[0333] As solvent, for example, ether solvent, ester solvent, aromatic hydrocarbon solvent, amide solvent mentioned for the formation of hole injection layer 3 can be cited, in addition, alkane solvent, halogenated aromatic hydrocarbon solvent, aliphatic alcohol solvent, alicyclic alcohol solvent, aliphatic ketone solvent and alicyclic ketone solvent etc. can be cited. The solvent used is also shown in the example of the solvent of the composition containing iridium coordination compound of the present invention. The specific example of solvent is cited below, and solvent is not limited to these as long as it does not damage the effect of the present invention.

[0334] Examples of the solvent include aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); aromatic ether solvents such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethyl ether, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether; aromatic ester solvents such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; and toluene, xylene, mesitylene, cyclohexane, and the like. Aromatic hydrocarbon solvents such as 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, and methylnaphthalene; amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; alkane solvents such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; alicyclic alcohol solvents such as cyclohexanol and cyclooctanol; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; alicyclic ketone solvents such as cyclohexanone, cyclooctanone, and fenchone. Among these, alkane solvents and aromatic hydrocarbon solvents are particularly preferred.

[0335] In order to obtain a more uniform film, it is preferred that the solvent evaporates at an appropriate rate from the liquid film immediately after film formation. Therefore, the boiling point of the solvent used is generally 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, as described above, and generally 270°C or lower, preferably 250°C or lower, more preferably 230°C or lower.

[0336] The amount of solvent used is arbitrary as long as it does not significantly impair the effect of the present invention. From the perspective of easy film formation due to low viscosity, the total content in the composition for forming a light-emitting layer, that is, the composition containing the iridium coordination compound is preferably large, and from the perspective of easy film formation with a thick film, it is preferably low. As described above, the content of the solvent in the composition containing the iridium coordination compound is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, and preferably 99.99% by mass or less, more preferably 99.9% by mass or less, and particularly preferably 99% by mass or less.

[0337] As a method for removing the solvent after wet film formation, heating or reduced pressure can be used. As a heating means used in the heating method, a clean oven or a hot plate is preferred from the viewpoint of uniformly applying heat to the entire film.

[0338] The heating temperature in the heating process is arbitrary as long as it does not significantly impair the effect of the present invention. From the perspective of shortening the drying time, a higher temperature is preferred, and from the perspective of less damage to the material, a lower temperature is preferred. The upper limit of the heating temperature is usually below 250°C, preferably below 200°C, and more preferably below 150°C. The lower limit of the heating temperature is usually above 30°C, preferably above 50°C, and more preferably above 80°C. The heating temperature exceeding the above upper limit is higher than the heat resistance of the commonly used charge transport material or phosphorescent material, and decomposition and crystallization may occur, so it is not preferred. When the heating temperature is less than the above lower limit, the removal of the solvent requires a long time, so it is not preferred. The heating time in the heating process can be appropriately determined according to the boiling point of the solvent in the composition for forming the light-emitting layer, the vapor pressure, the heat resistance of the material and the heating conditions.

[0339] (Formation of Light Emitting Layer 5 by Vacuum Deposition)

[0340] When the light-emitting layer 5 is formed by vacuum deposition, one or more constituent materials of the light-emitting layer 5 (the light-emitting material, charge transporting compound, etc.) are usually placed in a crucible (when two or more materials are used, each is usually placed in a different crucible) provided in a vacuum container, and the vacuum container is evacuated to 100°C by a vacuum pump. －4 After about 100 Pa, the crucible is heated (when two or more materials are used, each crucible is usually heated), and the material in the crucible is evaporated while controlling the evaporation amount (when two or more materials are used, each is usually evaporated while controlling the evaporation amount independently), and the light-emitting layer 5 is formed on the hole injection layer 3 or the hole transport layer 4 placed opposite to the crucible. When two or more materials are used, their mixture can also be placed in a crucible, heated, and evaporated to form the light-emitting layer 5.

[0341] The vacuum degree during vapor deposition is not limited unless the effect of the present invention is significantly impaired, but is usually 0.1×10 － 6 Torr(0.13×10 －4 Pa) and above 9.0×10 －6 Torr(12.0×10 －4 The evaporation rate is not limited as long as it does not significantly impair the effect of the present invention, and is usually / second or more and The film forming temperature during vapor deposition is not limited unless the effects of the present invention are significantly impaired, but is preferably 10° C. to 50° C.

[0342] <Hole blocking layer 6>

[0343] A hole blocking layer 6 may be provided between the light emitting layer 5 and the electron injection layer 8 described later. The hole blocking layer 6 is a layer stacked on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.

[0344] The hole blocking layer 6 has the function of blocking holes migrated from the anode 2 from reaching the cathode 9 and efficiently transporting electrons injected from the cathode 9 toward the light-emitting layer 5. The physical properties required of the material constituting the hole blocking layer 6 include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and a high excited triplet energy level (T1).

[0345] As materials for the hole blocking layer 6 that satisfy such conditions, for example, there can be mentioned mixed ligand complexes such as bis(2-methyl-8-hydroxyquinolinolato)(phenol)aluminum, bis(2-methyl-8-hydroxyquinolinolato)(triphenylsilanol)aluminum, metal complexes such as bis(2-methyl-8-hydroxyquinolinolato)aluminum-μ-oxo-bis(2-methyl-8-hydroxyquinolinolato)aluminum binuclear metal complex, styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Application Publication No. 11-242996), triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Application Publication No. 7-41759), and phenanthroline derivatives such as bathocuproin (Japanese Patent Application Publication No. 10-79297). Furthermore, the compound having at least one pyridine ring substituted at the 2-, 4-, or 6-position described in International Publication No. 2005 / 022962 is also preferably used as the material for the hole blocking layer 6 .

[0346] The method for forming the hole blocking layer 6 is not limited, and the hole blocking layer 6 can be formed in the same manner as the method for forming the light emitting layer 5 described above.

[0347] The thickness of the hole blocking layer 6 is arbitrary unless the effect of the present invention is significantly impaired, and is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

[0348] <Electron transport layer 7>

[0349] The electron transport layer 7 is provided between the light emitting layer 5 or the hole blocking layer 6 and the electron injection layer 8 for the purpose of further improving the current efficiency of the device.

[0350] The electron transport layer 7 is formed of a compound that can efficiently transport electrons injected from the cathode 9 between electrodes providing an electric field toward the light-emitting layer 5. The electron transport compound used in the electron transport layer 7 needs to have a high electron injection efficiency from the cathode 9 or the electron injection layer 8, a high electron mobility, and be able to efficiently transport the injected electrons.

[0351] Examples of electron transporting compounds that satisfy such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Application Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo[h]quinoline, Oxadiazole derivatives, distyryl biphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzo Azole metal complexes, benzothiazole metal complexes, tribenzimidazolylbenzene (U.S. Patent No. 5645948), quinoxaline compounds (Japanese Patent Publication No. 6-207169), phenanthroline derivatives (Japanese Patent Publication No. 5-331459), 2-tert-butyl-9,10-N,N'-dicyanoanthraquinone diimide, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide, etc.

[0352] The film thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[0353] The electron transport layer 7 is formed by laminating on the light-emitting layer 5 or the hole blocking layer 6 by a wet film forming method or a vacuum deposition method similarly to the light-emitting layer 5. Usually, the vacuum deposition method can be used.

[0354] <Electron injection layer 8>

[0355] The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the electron transport layer 7 or the light-emitting layer 5 .

[0356] In order to efficiently inject electrons, the material forming the electron injection layer 8 is preferably a metal having a low work function. For example, alkali metals such as sodium and cesium, and alkaline earth metals such as barium and calcium can be used.

[0357] The film thickness of the electron injection layer 8 is preferably 0.1 to 5 nm.

[0358] Inserting an extremely thin insulating film (film thickness of about 0.1 to 5 nm) such as LiF, MgF2, Li2O, Cs2CO3 as the electron injection layer 8 at the interface between the cathode 9 and the electron transport layer 7 is also an effective method to improve the efficiency of the device (Appl. Phys. Lett., Vol. 70, p. 152, 1997; Japanese Patent Gazette No. 10-74586; IEEE Trans. Electron. Devices, Vol. 44, p. 1245, 1997; SID 04 Digest, p. 154).

[0359] By doping an organic electron transport material represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline and an aluminum complex of 8-hydroxyquinoline with an alkali metal such as sodium, potassium, cesium, lithium, and rubidium (described in Japanese Patent Laid-Open No. 10-270171, Japanese Patent Laid-Open No. 2002-100478, Japanese Patent Laid-Open No. 2002-100482, etc.), it is possible to improve electron injection and transport properties and have excellent film quality, so it is preferred. The film thickness at this time is usually 5 nm or more, preferably 10 nm or more, usually 200 nm or less, preferably 100 nm or less.

[0360] The electron injection layer 8 is formed by laminating on the light-emitting layer 5 or the hole blocking layer 6 or the electron transport layer 7 thereon by a wet film forming method or a vacuum deposition method in the same manner as the light-emitting layer 5 .

[0361] The details of the wet film formation method are the same as those of the above-mentioned light-emitting layer 5 .

[0362] <Cathode 9>

[0363] The cathode 9 plays a role in injecting electrons into the layer (electron injection layer 8 or light-emitting layer 5, etc.) on the side of the light-emitting layer 5. As the material of the cathode 9, the material used in the above-mentioned anode 2 can be used. From the perspective of efficient electron injection, it is preferred to use a metal with a low work function. As the material of the cathode 9, for example, metals such as tin, magnesium, indium, calcium, aluminum, silver, or their alloys can be used. As a specific example, alloy electrodes with low work functions such as magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys can be cited.

[0364] From the perspective of device stability, it is preferred to stack a metal layer having a high work function and being stable to the atmosphere on cathode 9 to protect cathode 9 made of a metal having a low work function. Examples of the stacked metal include aluminum, silver, copper, nickel, chromium, gold, and platinum.

[0365] The cathode film thickness is usually the same as that of the anode 2 .

[0366] <Other constituent layers>

[0367] Above, Figure 1The elements having the layer structure shown are described mainly, but between the anode 2 and the cathode 9 and the light-emitting layer 5 in the organic electroluminescent element of the present invention, any layer other than the layers described above may be present as long as the performance is not impaired. In addition, any layer other than the light-emitting layer 5 may be omitted.

[0368] For example, it is also effective to provide an electron blocking layer between the hole transport layer 4 and the light-emitting layer 5 for the same purpose as the hole blocking layer 8. The electron blocking layer blocks the electrons migrating from the light-emitting layer 5 from reaching the hole transport layer 4, thereby having the following effects: increasing the probability of recombination with holes in the light-emitting layer 5, confining the generated excitons in the light-emitting layer 5, and efficiently transporting the holes injected from the hole transport layer 4 toward the light-emitting layer 5.

[0369] The properties required of the electron blocking layer include high hole transporting property, large energy gap (difference between HOMO and LUMO), and high excited triplet energy level (T1).

[0370] When the light-emitting layer 5 is formed by a wet film-forming method, it is preferable to also form the electron blocking layer by a wet film-forming method because this facilitates device production.

[0371] Therefore, the electron blocking layer also preferably has wet film formation suitability, and examples of materials used for such an electron blocking layer include copolymers of dioctylfluorene and triphenylamine represented by F8-TFB (International Publication No. 2004 / 084260) and the like.

[0372] It can also be with Figure 1 The reverse structure is that the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, the hole transport layer 4, the hole injection layer 3, and the anode 2 are stacked in this order on the substrate 1. The organic electroluminescent element of the present invention may also be provided between two substrates, at least one of which is highly transparent.

[0373] It can also overlap multiple segments Figure 1 In this case, if V2O5 or the like is used as a charge generation layer instead of the interface layer between the segments (light-emitting units) (these two layers when the anode is ITO and the cathode is Al), the potential barrier between the segments becomes smaller, which is more preferable from the perspective of luminous efficiency and driving voltage.

[0374] The organic electroluminescent element of the present invention can be applied to a single element, an element having a structure arranged in an array, or a structure in which anodes and cathodes are arranged in an X-Y matrix.

[0375] [Display device and lighting device]

[0376] The organic electroluminescent element of the present invention can be used to manufacture display devices and lighting devices. The form and structure of the display device and lighting device using the organic electroluminescent element of the present invention are not particularly limited, and the organic electroluminescent element of the present invention can be used and assembled according to conventional methods.

[0377] For example, a display device and a lighting device can be formed using the organic electroluminescent element of the present invention by the method described in "Organic EL Display" (Ohm Co., Ltd., published on August 20, 2001, written by Shizuo Tokito, Chihaya Adachi, and Hideyuki Murata).

[0378] Example

[0379] Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following Examples, and the present invention can be implemented with any modifications without departing from the gist of the present invention.

[0380] In the following synthesis examples, the reactions were all carried out under a nitrogen stream. The solvents and solutions used in the reactions were degassed by an appropriate method such as nitrogen bubbling.

[0381] [Synthesis of Iridium Coordination Compounds]

[0382] <Synthesis Example 1: Synthesis of Comparative Compound 1>

[0383]

[0384] 12.53 g of 2-aminobenzophenone and 120 cc of dichloromethane were placed in a 500 cc eggplant flask and placed in an ice bath. A slurry mixture of 11.43 g of N-bromosuccinimide and 30 cc of dichloromethane was added thereto, stirred for 10 minutes, and then stirred at room temperature for 1 hour. After standing overnight, the mixture was separated and washed with 500 cc of water, extracted from the aqueous phase with 200 cc of dichloromethane, and the oil phases were combined and dried with 20 g of magnesium sulfate. The solvent was removed under reduced pressure, and the residue was purified by silica gel column chromatography (500 cc of neutral silica gel, dichloromethane / hexane = 7 / 3 to 85 / 15). As a result, 16.67 g of 2-amino-4-bromobenzophenone was obtained as a yellow solid.

[0385]

[0386] 10.02 g of 2-amino-4-bromobenzophenone, 10.02 g of 2-acetylfluorene, 4.28 g of potassium hydroxide, and 100 cc of ethanol were placed in a 100 cc eggplant-shaped flask and stirred for 2.5 hours in an oil bath at 100°C. After cooling to room temperature, the precipitated solid was filtered and washed three times with 50 cc of ethanol. After drying, 7.47 g of Intermediate 1 was obtained as a light yellow solid.

[0387]

[0388] In a 300cc eggplant-shaped flask, 7.47g of intermediate 1, 5.44g of 3-(6-phenyl-n-hexyl)phenylboronic acid (see WO2016-194784A1), 1.21g of tetrakis(triphenylphosphine)palladium(0), 30cc of 2mol / L tripotassium phosphate aqueous solution, 65cc of toluene and 30cc of ethanol were placed and stirred in an oil bath at 100°C for 1.5 hours. After cooling to room temperature, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral gel 750cc, dichloromethane / hexane = 1 / 1). As a result, 7.83g of intermediate 2 was obtained as a yellow solid.

[0389]

[0390] 7.83 g of intermediate 2 was placed in a 1L eggplant-shaped flask and dissolved in 50 cc of dry tetrahydrofuran and 6.50 g of methyl iodide. 3.74 g of sodium tert-butoxide was then added and stirred at room temperature for 5.5 hours. On the way, 3.74 g of potassium tert-butoxide was added after 3 hours, and 4.29 g of methyl iodide was added after 5 hours. After the reaction was completed, the reaction was filtered and the filtered product was washed with 50 cc of tetrahydrofuran. The filtrate was combined with the washing liquid, the solvent was removed, and the obtained residue was purified by silica gel column chromatography (neutral silica gel 400 cc, dichloromethane / hexane = 1 / 1). As a result, 4.69 g of intermediate 3 was obtained as a colorless amorphous solid.

[0391]

[0392] In a 100cc eggplant-shaped flask equipped with a serpentine condenser with a side tube, 1.53g of intermediate 3 and 0.46g of iridium chloride n-hydrate (manufactured by Furuya Metals, iridium content 51.25wt%) were placed, 25cc of 2-ethoxyethanol and 5cc of water were added, and stirred in an oil bath at 135°C for 5 hours, and then set to 140°C and stirred for 3 hours. After standing at room temperature overnight, it was stirred again at 140°C for 9.5 hours. During this period, 10cc of the liquid distilled from the side tube was removed. 1.60g of 3,5-heptanedione and 1.56g of sodium carbonate were added to the reaction solution cooled to room temperature, and stirred in an oil bath at 135°C for 40 minutes. The solvent was removed under reduced pressure, and the obtained residue was purified by column silica gel chromatography (neutral silica gel, dichloromethane). As a result, 1.74g of intermediate 4 was obtained as a red amorphous solid.

[0393]

[0394] 1.74 g of intermediate 4 and 1.41 g of intermediate 3 were placed in a 100 cc eggplant flask, and the mixture was heated to 270°C while stirring using an aluminum block heater (RCH-1000 manufactured by EYELA) to make it melt evenly. After cooling to 240°C, 0.2 g of silver (I) trifluoromethanesulfonate was added and stirred at 240°C for 80 minutes. After cooling to room temperature, the obtained mixture was purified by silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 0.83 g of comparative compound 1 was obtained as a dark red solid.

[0395] <Synthesis Example 2: Synthesis of Compound 1>

[0396]

[0397] In a 500 ml eggplant-shaped flask, 10.4 g of intermediate 1 and 150 ml of dry tetrahydrofuran were placed to prepare a solution, which was then placed in an ice-water bath. Thereafter, 7.77 g of potassium tert-butoxide was added, and after stirring for 10 minutes, 4.5 ml of iodomethane was added. After the heating was completed, the mixture was stirred at room temperature for 2.5 hours, and then 150 ml of water was added. The precipitated solid was separated by filtration, washed with water and methanol, and then dried. As a result, 10.91 g of intermediate 5 was obtained as a light orange solid.

[0398]

[0399] 9.0 g of 2,6-dibromo-m-xylene, 8.0 g of 3-(6-phenyl-n-hexyl)phenylboric acid, 0.79 g of tetrakis(triphenylphosphine)palladium(0), 43 ml of 2 mol / L potassium phosphate aqueous solution, 60 ml of toluene and 30 ml of ethanol were placed in a 500 ml eggplant flask and stirred in an oil bath at 90°C for 5 hours. After cooling to room temperature, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral gel 750 cc, dichloromethane / hexane = 1 / 9). As a result, 11.3 g of intermediate 6 was obtained as a yellow solid.

[0400]

[0401] 0.84 g of magnesium chips was placed in a 300 ml four-necked flask, and intermediate 6 dissolved in 25 ml of dry tetrahydrofuran was added dropwise at room temperature over 10 minutes using a syringe. Then, the syringe was rinsed with 10 ml of tetrahydrofuran, which was also added dropwise. Then, it was immersed in a 90°C oil bath and stirred for 70 minutes. Then, after cooling in a dry ice-acetone bath, 5 ml of trimethoxyborane dissolved in 45 ml of dry tetrahydrofuran was added dropwise over 10 minutes using a syringe. Then, after stirring at room temperature for 30 minutes, 20 ml of tetrahydrofuran was added, and the mixture was stirred in an oil bath at 60°C for 70 minutes. Then, 40 ml of 2N-HCl was added and stirred while cooling in an ice water bath. After the foaming was completed, 100 ml of dichloromethane was added for extraction, and then the mixture was dried with magnesium sulfate, and the solvent was removed under reduced pressure. As a result, 12.33 g of intermediate 7 was obtained as a light brown oily substance as a mixture with tetrahydrofuran.

[0402]

[0403] 7.53 g of intermediate 5, 12.33 g of intermediate 7, 0.92 g of tetrakis(triphenylphosphine)palladium(0), 12.5 g of barium hydroxide octahydrate, 130 ml of 1,2-dimethoxyethane and 20 ml of water were placed in a 500 ml eggplant flask and stirred in an oil bath at 100°C for 1.5 hours. 2.14 g of intermediate 5 was added 40 minutes after the start of the reaction. After cooling to room temperature, the mixture was filtered and the filtrate was concentrated under reduced pressure. The obtained residue was extracted with 150 ml of ethyl acetate and 50 ml of water. The oil phase was washed with saturated saline and dried with magnesium sulfate. After filtering, the solvent was removed under reduced pressure and the obtained residue was purified by silica gel column chromatography (neutral gel 700 cc, dichloromethane / hexane = 1 / 1). As a result, 13.55 g of intermediate 8 was obtained as a light yellow solid.

[0404]

[0405] In a 200cc eggplant-shaped flask equipped with a serpentine condenser with a side tube, 4.32g of intermediate 8 and 1.05g of iridium chloride n-hydrate (manufactured by Furuya Metals, iridium content 51.25wt%) were placed, 60ml of 2-ethoxyethanol and 10ml of water were added, and the mixture was stirred in an oil bath at 125°C for 1 hour, and then stirred at 135°C for 4.5 hours. After standing at room temperature overnight, the mixture was stirred again at 135°C for 6.5 hours. During this period, 12ml of the liquid distilled from the side tube was removed. 1.5g of 3,5-heptanedione and 2.36g of sodium carbonate were added to the reaction solution cooled to room temperature, and the mixture was stirred in an oil bath at 135°C for 40 minutes. The solvent was removed under reduced pressure, and the obtained residue was purified by column silica gel chromatography (neutral silica gel, dichloromethane / hexane). As a result, 4.50g of intermediate 9 was obtained as a red amorphous solid.

[0406]

[0407] 4.50 g of intermediate 9 and 1.53 g of intermediate 8 were placed in a 100 ml eggplant flask, and the mixture was heated while stirring in a 200° C. oil bath to make it melt uniformly. 0.53 g of silver (I) trifluoromethanesulfonate was then added, and the mixture was stirred at 240° C. for 1 hour. After cooling to room temperature, the obtained mixture was purified by silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 0.98 g of compound 1 was obtained as a dark red solid.

[0408] <Synthesis Example 3: Synthesis of Compound 2>

[0409]

[0410] 25.20 g of 2-iodobromobenzene, 20.41 g of 3-(6-phenyl-n-hexyl)phenylboric acid, 3.60 g of tetrakis(triphenylphosphine)palladium(0), 90 ml of 2M tripotassium phosphate aqueous solution, 100 ml of toluene and 70 ml of ethanol were placed in a 500 ml eggplant-shaped flask and stirred in an oil bath at 105°C for 2 hours. After removing the aqueous phase, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 23.56 g of 3-(6-phenyl-n-hexyl)-2'-bromo-1,1'-biphenyl was obtained as a colorless oily substance.

[0411]

[0412] 23.56 g of 3-(6-phenyl-n-hexyl)-2'-bromo-1,1'-biphenyl, 17.56 g of bis(pinacolato)diboron, 29.66 g of potassium acetate, 1.50 g of [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane adduct and 200 ml of dimethyl sulfoxide were placed in a 1 L eggplant flask and stirred for a total of 15 hours in an oil bath at 90°C. 2.11 g of [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane adduct was added during the reaction. After the reaction was completed, 1 L of water and 0.45 L of dichloromethane were added for separation, and the oil phase was washed with 0.5 L of water. After drying with magnesium sulfate (volume: about 20 ml), the mixture was filtered and the solvent was removed under reduced pressure. The obtained residue was purified by silica gel column chromatography (neutral gel, dichloromethane / hexane) to obtain 23.16 g of intermediate 10 as a dark yellow oily substance. The wavy line in the structural formula of intermediate 10 indicates a mixture of rotamers.

[0413]

[0414] In a 1L eggplant-shaped flask, 14.76 g of intermediate 1, 23.16 g of intermediate 10, 2.88 g of tetrakis(triphenylphosphine)palladium(0), 70 ml of 2M tripotassium phosphate aqueous solution, 160 ml of toluene and 80 ml of ethanol were placed and stirred in an oil bath at 105°C for 2 hours. The aqueous phase was then removed, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, dichloromethane / hexane).

[0415] As a result, 21.98 g of intermediate 11 was obtained as a cream-colored solid.

[0416]

[0417] 21.98 g of intermediate 11, 11.0 g of potassium tert-butoxide, and 200 ml of tetrahydrofuran were placed in a 1 L eggplant-shaped flask and stirred at room temperature to form a black suspension. The mixture was immersed in an ice-water bath and 6.0 ml of iodomethane was injected over 1 minute. The mixture was then stirred at room temperature for 2 hours. After the solvent was removed under reduced pressure, 0.5 L of water and 0.3 L of dichloromethane were added for liquid separation, and the oil phase was dried using magnesium sulfate. The solvent was removed from the dried oil phase under reduced pressure, and the obtained solid was refined using silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 16.18 g of intermediate 12 was obtained in the form of yellow amorphous.

[0418]

[0419] In a 200cc eggplant-shaped flask equipped with a serpentine condenser with a side tube, 11.75g ​​of intermediate 12 and 3.10g of iridium chloride n-hydrate (manufactured by Furuya Metals, iridium content 51.25wt%) were placed, 150ml of 2-ethoxyethanol and 25ml of water were added, and stirred in an oil bath at 135°C for 2 hours, and then set to 140°C and stirred for 6.5 hours. After standing at room temperature overnight, stir again at 140°C for 10 hours. During this period, 55ml of the liquid distilled from the side tube was removed. The solvent was removed under reduced pressure, and the obtained residue was purified by column silica gel chromatography (neutral silica gel, dichloromethane / hexane). As a result, 6.98g of dark red intermediate 13 was obtained.

[0420]

[0421] In a 500 ml eggplant-shaped flask, 6.98 g of intermediate 13, 2.98 g of 3,5-heptanedione, 4.50 g of sodium carbonate, and 100 ml of 2-ethoxyethanol were placed, and the inside was washed with 20 ml of dichloromethane, and then immersed in an oil bath, and stirred for 1 hour while the oil temperature was raised to 135°C. The solvent was then removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 4.95 g of intermediate 14 was obtained as a dark red solid.

[0422]

[0423] 4.95 g of intermediate 14, 3.98 g of intermediate 12 and 0.2 mL of phenylcyclohexane were placed in a 100 ml eggplant flask, melted and stirred using an aluminum block heater at 240°C. 0.73 g of silver (I) trifluoromethanesulfonate was then added and stirred for 1.5 hours. After cooling, 50 ml of dichloromethane was added and dissolved, 30 ml of neutral silica gel was added, the solvent was removed under reduced pressure, and the adsorbed gel was purified using silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 0.95 g of compound 2 was obtained as a dark red solid.

[0424] <Synthesis Example 4: Synthesis of Comparative Compound 2>

[0425]

[0426] In a 1L eggplant-shaped flask, 15.71 g of intermediate 1, 11.76 g of potassium tert-butoxide, and 200 ml of tetrahydrofuran were placed and stirred at room temperature for 30 minutes. Afterwards, the mixture was immersed in an ice-water bath, 25.13 g of 1-iodooctane was added, and the mixture was stirred for another 30 minutes. The solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 18.66 g of yellow amorphous intermediate 15 was obtained.

[0427]

[0428] In a 1L eggplant-shaped flask, 18.66 g of intermediate 15, 3.72 g of phenylboric acid, 2.37 g of tetrakis(triphenylphosphine)palladium(0), 40 ml of 2M potassium phosphate aqueous solution, 80 ml of toluene and 40 ml of ethanol were placed and stirred in an oil bath at 100°C for 2.5 hours. After removing the aqueous phase, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 18.14 g of yellow amorphous intermediate 16 was obtained.

[0429]

[0430] In a 200cc eggplant-shaped flask equipped with a serpentine condenser with a side tube, 6.16g of intermediate 16 and 1.74g of iridium chloride n-hydrate (manufactured by Furuya Metals, iridium content 51.25wt%) were placed, 80ml of 2-ethoxyethanol and 20ml of water were added, and stirred in an oil bath at 145°C for 7 hours, and then further stirred at 160°C for 3 hours. During this period, 50ml of ethoxyethanol was added after 9 hours. The liquid distilled from the side tube was 100ml. 2.47g of acetylacetone and 4.75g of sodium carbonate were added to the reaction solution cooled to room temperature, and stirred in an oil bath at 100°C for 30 minutes. The solvent was removed under reduced pressure, and the obtained residue was purified by column silica gel chromatography (neutral silica gel, dichloromethane / hexane).

[0431] As a result, 4.71 g of Intermediate 17 was obtained as a red amorphous solid.

[0432]

[0433] 2.02 g of intermediate 17, 2.78 g of intermediate 16 and 0.15 mL of phenylcyclohexane were placed in a 100 ml eggplant flask, melted and stirred using an aluminum block heater at 240°C. 0.39 g of silver (I) trifluoromethanesulfonate was then added and stirred for 30 minutes. After cooling, 50 ml of dichloromethane was added and dissolved, 20 ml of neutral silica gel was added, the solvent was removed under reduced pressure, and the adsorbed gel was purified using silica gel column chromatography (neutral silica gel, dichloromethane / hexane). As a result, 1.91 g of comparative compound 2 was obtained as a red solid.

[0434] <Synthesis Example 5: Synthesis of Compound 3>

[0435] In the reaction of synthesizing intermediate 4 from intermediate 3, compound 3 shown below was synthesized by the same method except that acetylacetone was used instead of 3,5-heptanedione.

[0436]

[0437] Using cyclohexylbenzene as a solvent, compounds 1 to 3 and comparative compounds 1 and 2 were mixed to give 3 wt % and observed whether they dissolved at 70° C. As a result, all of them dissolved, confirming that the solubility in the solvent was good.

[0438] Comparative compound 3 was synthesized using intermediate 8 according to the method described in WO2015-087961A1.

[0439] Reference compounds 1 to 6 were synthesized with reference to this synthesis example. These belong to a series of fac-tricyclometallated iridium coordination compounds that differ only in the hydrocarbon substituents in the phenylquinoline ligand. They are used as references to show the relationship between the spectral half width and quantum yield when the emission wavelength is changed with almost no change in the atomic environment near the iridium atom.

[0440] [Comparative Compound 3]

[0441]

[0442] [Reference compound 1]

[0443]

[0444] [Reference compound 2]

[0445]

[0446] [Reference compound 3]

[0447]

[0448] [Reference compound 4]

[0449]

[0450] [Reference compound 5]

[0451]

[0452] [Reference compound 6]

[0453]

[0454] [Measurement of luminescence maximum wavelength and half-width]

[0455] Compound 1 was dissolved in 2-methyltetrahydrofuran (manufactured by Aldrich, dehydrated, without adding stabilizer) at room temperature to prepare 1×10 －5mol / L solution. The solution was placed in a quartz cell with a Teflon (registered trademark) stopcock, and after nitrogen bubbling for more than 20 minutes, the phosphorescence spectrum was measured at room temperature. The wavelength representing the maximum value of the obtained phosphorescence spectrum intensity was set as the maximum emission wavelength (luminescence maximum wavelength). In addition, the width of the spectrum intensity at half the maximum emission wavelength was set as the half width. －1 The half width is expressed by reading the shorter wavelengths exceeding the height 0.5 and the longer wavelengths below the height 0.5 from the data of the spectrum normalized to the conversion height 1, and converting nm to cm －1 , and set the difference to cm －1 half width.

[0456] The following equipment was used for the measurement of the emission spectrum.

[0457] Device: Organic EL quantum yield measurement device C9920-02 manufactured by Hamamatsu Photonics Co., Ltd. Light source: Monochromatic light source L9799-01

[0458] Detector: Multi-channel detector PMA-11

[0459] Excitation light: 380nm

[0460] [Measurement of PL quantum yield]

[0461] As the luminous efficiency, the PL quantum yield was measured. The PL quantum yield is an index showing how efficiently light (energy) absorbed by a material can be emitted, and was measured using the following equipment in the same manner as described above.

[0462] Device: Organic EL quantum yield measurement device C9920-02 manufactured by Hamamatsu Photonics Co., Ltd. Light source: Monochromatic light source L9799-01

[0463] Detector: Multi-channel detector PMA-11

[0464] Excitation light: 380nm

[0465] The half width, emission maximum wavelength and PL quantum yield of Compounds 2 to 3, Reference Compounds 1 to 6 and Comparative Compounds 1 to 3 were measured in the same manner.

[0466] [Table 1]

[0467]

[0468] Table 1 is a table showing the half width, emission maximum wavelength and PL quantum yield values ​​of compounds 1 to 3, reference compounds 1 to 6 and comparative compounds 1 to 3. It can be seen that the half width of compounds 1 to 3 and comparative compounds 1 to 3 is narrow enough in the region above 620nm of the emission maximum wavelength that can be used as red coloring materials. On the other hand, it can be seen that the PL quantum yield can obtain the same level of performance as before. By adding an aromatic group to a predetermined position of quinoline, an iridium complex can be obtained in which the quantum yield does not drop significantly even when fluorene is tri-coordinated while maintaining a narrow half width.

[0469] It can be seen that compared with comparative compounds 1 and 2, compound 1 has a smaller half width and a higher PL quantum yield, and can be used to produce an excellent light-emitting element in a top emission type element. 18 and R 22 The presence of an alkyl (methyl) group generates steric hindrance between the quinoline ring and the bond is twisted, so that the conjugation length is shortened and the unnecessary wavelength is suppressed. As a result, it is considered that the quantum yield is higher than that of the comparative compound 1. In addition, since the torsion tip R 20 Since the aromatic ring and the aralkyl group are present at the position of , it is considered that the solubility is increased.

[0470] Compound 2 is equivalent to R 22 Since the position of has an aromatic ring or an aralkyl group, steric hindrance is generated between the quinoline ring and the bond is twisted as in compound 1, so the conjugation length is shortened and the unnecessary wavelength increase is suppressed. As a result, it is believed that the quantum yield is higher than that of comparative compound 1, for example.

[0471] Comparative Compound 2 13 , R 17 , R 18 and R 22 Since all of them are hydrogen atoms, it is considered that sufficient twisting is not formed between the quinoline ring and the benzene ring. As a result, the emission maximum wavelength becomes longer than that of Compounds 1 and 2.

[0472] Compound 3 has an extremely narrow half width and a high quantum yield.

[0473] Figure 2It is a graph showing the relationship between the maximum wavelength and half width of the emission of compounds 1 to 3, reference compounds 1 to 6, and comparative compounds 1 to 3. The dotted line represents the approximate straight line between the maximum wavelength and half width of the emission of the reference compound 1 to 6 group. There is a tendency for the half width to become wider when the maximum wavelength of the emission becomes a long wavelength in the reference compound 1 to 6 group having a phenyl-quinoline ligand without a fluorene structure. In contrast, it can be seen that compounds 1 to 3 and comparative compounds 1 to 3 can achieve a narrow half width in the region above 620nm of the maximum wavelength of emission suitable as a red light-emitting material, and are suitable for top-emitting laminates. It can be seen that compounds 1 to 3 are particularly excellent in both half width and maximum wavelength of emission.

[0474] Figure 3 This is a graph showing the relationship between the maximum emission wavelength and the PL quantum yield of compounds 1 to 3, reference compounds 1 to 6, and comparative compounds 1 to 3. In general, long-wavelength red light-emitting materials tend to have a decreasing PL quantum yield according to the energy gap law. The dotted line represents the approximate straight line between the maximum emission wavelength and the PL quantum yield of the reference compound group 1 to 6. The reference compound group 1 to 6 having a phenyl-quinoline ligand without a fluorene structure has a tendency to decrease the PL quantum yield when the maximum emission wavelength is a long wavelength. In contrast, it can be seen that compounds 1 to 3 can also obtain a high PL quantum yield in the region of the maximum emission wavelength of 620nm or more.

[0475] From the above results, it can be seen that compounds 1 to 3 have narrow half-value widths in the region of the emission maximum wavelength of 620 nm or longer and can achieve PL quantum yields comparable to those of conventional compounds. Therefore, excellent luminescence performance can be obtained in top emission type laminates.

[0476] [Comparison of T1 level luminescence maximum wavelength]

[0477] The comparison of the emission maximum wavelengths of the compound 4 and the comparative compound 4 shown below was performed by calculation using the density functional method. The excitation energy of the T level was calculated from the energy difference between the ground state and the T1 level state, and the T1 level emission maximum wavelength was calculated. The results are shown in Table 2.

[0478]

[0479] Compound 4 can be synthesized in the same manner as Compound 1 except that phenylboronic acid is used instead of 3-(6-phenyl-n-hexyl)phenylboronic acid in the synthesis of Intermediate 6, and 2-bromo-6-phenyl-m-xylene having no 6-phenyl-n-hexyl group is synthesized instead of Intermediate 6.

[0480] When calculating the emission wavelength, i.e., the T1 level, the commercially available electronic state calculation software Gaussian09, Revision B.01, was used (see the following ※). At this time, as a quantum chemical calculation method, the density functional method (Density Functional Theory) was adopted, and the functional used was B3LYP. As the basis function, for Ir atoms, the function obtained by adding the diffuse d function (exponent = 0.07) and the f function (exponent = 0.938) to the function substituted by Coutry and Hall using the optimized coefficients of the 6p orbital based on LANL2DZ was used (references: J. Comp. Chem. 17.1359 (1996), J. Am. Chem. Soc. 126.13044 (2004)). 6-31G was used for other atoms. The structural optimization calculation of the ground state and T1 energy level based on b3LYP is performed, and the excitation energy of the T energy level is calculated based on the energy difference between the ground state and the T1 energy level, and the maximum wavelength of the emission of the T1 energy level is calculated.

[0481] ※Gaussian 09, Revision B.01,

[0482] MJ Frisch, GW Trucks, HB Schlegel, GEScuseria, MA Robb, J R Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G A Petersson, H. Nakatsuji, M. Caricato, X. Li, H P Hratchian, AFIzmaylov, J. Bloino, G. Zheng, J L Sonnenberg, M. Hada, M .Ehara, K.Toyota, R.Fukuda, J.Hasegawa, M.Ishida, T.Nakajima, Y.Honda, O.Kitao, H.Nakai, T.Vreven, JAMontg omery, Jr., J. E. Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N. Staroverov, T. Keith, R. Kobaya shi, J.Normand, K.Raghavachari, A.Rendell, JCBurant, SSIyengar, J.Tomasi, M.Cossi, N.Rega, JMMillam, M.Kle ne, JEKnox, JBCross, V.Bakken, C.Adamo, J.Jaramillo, R.Gomperts, REStratmann, O.Yazyev, AJAustin, R.Cammi, C.Pomelli, J.W.Ochterski, R.L.Martin, K.Morokuma, V.G.Zakrzewski, GAVoth, P.Salvador, J.J.Dannenberg, S.Dapprich, ADDaniels, O.Farkas, J.B.Foresman, J.V.Ortiz, J.Cioslowski, andD.J.Fox, Gaussian, Inc., Wallingford CT, 2010.

[0483] [Table 2]

[0484]

[0485] The calculation results show that the maximum wavelength of the emission of compound 4 is shorter than that of comparative compound 4. This is believed to be due to the fact that 18 and R 22The presence of a substituent generates steric hindrance between the quinoline ring and the benzene ring bonded thereto, thereby causing sufficient twisting.

[0486] Although the present invention has been described in detail using specific embodiments, it will be apparent to one skilled in the art that various modifications can be made without departing from the spirit and scope of the present invention.

[0487] This application is based on Japanese Patent Application No. 2019-002398 filed on January 10, 2019 and Japanese Patent Application No. 2019-184629 filed on October 7, 2019, the entire contents of which are incorporated herein by reference.

[0488] Explanation of symbols

[0489] 1 substrate

[0490] 2 Anode

[0491] 3 Hole injection layer

[0492] 4 Hole transport layer

[0493] 5. Luminous layer

[0494] 6 Hole blocking layer

[0495] 7 Electron Transport Layer

[0496] 8 Electron injection layer

[0497] 9 Cathode

[0498] 10 Organic electroluminescent elements

Claims

1. An iridium coordination compound represented by the following formula (2): In formula (2), Ir represents an iridium atom, R 1 ~R 12 are each independently selected from a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, and an aromatic group having 5 to 60 carbon atoms, The alkyl group and the aromatic group may be independently substituted by one or more R's. R' is independently selected from a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, and an aromatic group having 5 to 60 carbon atoms. The alkyl group and the aromatic group may be further substituted by one or more R", R" are each independently selected from a hydrogen atom, an aromatic group having 3 to 20 carbon atoms, R 13 ~R 22 are each independently a hydrogen atom or any one of the substituents represented by R', R 18 and R 22 Each of them is an alkyl group having 1 to 4 carbon atoms.

2. The iridium coordination compound according to claim 1, wherein The substituent R in the formula (2) 14 , R 15 , R 16 , R 19 , R 20 and R 21 At least one of the groups is an alkyl group or an aromatic ring group which may have a substituent.

3. The iridium coordination compound according to claim 2, wherein The substituent R in the formula (2) 14 , R 15 , R 16 , R 19 , R 20 and R 21 At least one of them is a substituted aromatic ring group, and the substituent is an aralkyl group.

4. The iridium coordination compound according to claim 1, wherein The substituent R in the formula (2) 11 With R 12 Each is independently a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, or an aromatic group having 5 to 60 carbon atoms which may be substituted with the above R'.

5. The iridium complex according to claim 3, represented by the following formula (3): 6 . A composition containing an iridium complex, comprising the iridium complex according to claim 1 and an organic solvent.

7. A method for manufacturing an organic electroluminescent element, wherein the organic electroluminescent element comprises an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate. At least one of the organic layers is formed by a wet film-forming method using the composition containing the iridium complex according to claim 6.

8. The method for manufacturing an organic electroluminescent element according to claim 7, wherein: The organic layer is a light-emitting layer.

9. An organic electroluminescent element comprising an anode, a cathode and at least one organic layer located between the anode and the cathode on a substrate, At least one of the organic layers is a light-emitting layer comprising the iridium complex according to any one of claims 1 to 5. 10 . A display device comprising the organic electroluminescent element according to claim 9 .

11. A lighting device comprising the organic electroluminescent element according to claim 9.

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