Iridium complex and light-emitting material comprising said compound

Abstract

To provide an iridium complex that exhibits an emission spectrum with a narrow half-width in the visible light region.SOLUTION: The invention provides an iridium complex such as a compound represented by formula (IR-27).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an iridium complex that is suitably used as a light-emitting material for organic electroluminescent devices and the like. [Background technology]

[0002] Organic electroluminescent devices have been attracting attention as displays for televisions and mobile phones, and there is a strong demand for improved luminous efficiency in order to put them to practical use in the future. The luminescent materials used in organic electroluminescent devices can be broadly classified into fluorescent materials that utilize luminescence from an excited singlet state, and phosphorescent materials that utilize luminescence from an excited triplet state. In organic electroluminescent devices, the use of phosphorescent materials as the luminescent material theoretically increases the luminous efficiency by four times compared to conventional fluorescent materials, and therefore phosphorescent materials have been actively developed.

[0003] For example, an iridium complex having a phenylpyridine ligand has been disclosed as a phosphorescent material that efficiently emits light in the green region (see Patent Documents 1 and 2 and Non-Patent Document 1).

[0004] [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special table 2003-526876 [Patent Document 2] Patent Publication No. 2011-121876 [Non-patent literature]

[0006] [Non-Patent Document 1] NHK STRL R&D, 2017, No. 164, pp. 68-74. Summary of the Invention [Problem to be solved by the invention]

[0007] The iridium complexes having phenylpyridine ligands described in Patent Documents 1 and 2 emit green light, but have a problem of poor color purity due to the broad shape of the emission spectrum. Light-emitting materials for display applications are desired to exhibit an emission spectrum with a narrow full width at half maximum (FWHM), and improving the color purity of green light-emitting materials in particular is a major technical challenge (see Non-Patent Document 1).

[0008] An object of the present invention is to provide an iridium complex that exhibits an emission spectrum with a narrow half-width in the visible light region (particularly the green to red region), and a light-emitting material using said compound. [Means for solving the problem]

[0009] In view of the above circumstances, the present inventors have been conducting extensive research into the relationship between the structure and luminescence properties of iridium complexes. As a result, they have discovered that when a specific substituent represented by general formula (7) is introduced into a specific position of an organic ligand represented by general formula (6), the emission of the iridium complex unexpectedly shifts to a longer wavelength and at the same time the half-width becomes very narrow. This molecular design approach has led to the successful development of an iridium complex that exhibits emission with a narrow half-width in the visible light region (especially the green to red region), which was previously difficult to achieve, and has led to the completion of the present invention. The above experimental facts were completely unknown in the past, and are new findings obtained by the present inventors through numerous detailed experiments.

[0010] [ka]

[0011] [ka] (In general formulas (6) and (7), Ir, N, ring A, X 1 , R 1 ~R 5 represents Ir, N, ring A, X in general formula (1) described later. 1 , R 1 ~R 5* is the bonding site with general formula (6).

[0012] That is, according to this application, the following invention is provided.

[0013] <1> 1. An iridium complex represented by the following general formula (1): [ka] (In general formula (1), Ir represents an iridium atom, N represents a nitrogen atom, and ring A represents a pyridine ring, a pyrimidine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, a pyrazole ring, an imidazole ring, or a triazole ring. R 1 , R 2 and R 3 Each of X independently represents a hydrogen atom or an alkyl group. 1 is N or C(R 6 ) stands for R 4 and R 5 Each independently represents an alkyl group. 6 represents a hydrogen atom or an alkyl group. L represents an anionic bidentate ligand. When a plurality of L's are present, they may be the same or different. m represents 1 to 3, and n represents 0 to 2, with the proviso that m+n=3. <2> 2. The iridium complex according to 1 above, wherein ring A is represented by the following general formula (2): [ka] (In the general formula (2), N represents a nitrogen atom. X 2 is N or C(R 12 ) stands for X. 3 is N or C(R 13 ) where X 2 When N, X 3 is C(R 13 ), and X 2 C(R 12 ) when X 3 is N. R 7 ~R 11 R each independently represents a hydrogen atom, an alkyl group, or an aryl group.12 and R 13 each independently represents an alkyl group or an aryl group. <3> 2. The iridium complex according to 1 above, wherein ring A is represented by the following general formula (3): [ka] (In the general formula (3), N represents a nitrogen atom. R 14 represents an alkyl group or an aryl group. 15 and R 16 each independently represents a hydrogen atom, an alkyl group, or an aryl group. <4> 2. The iridium complex according to 1 above, wherein ring A is represented by the following general formula (4): [ka] (In the general formula (4), N represents a nitrogen atom. R 17 ~R 22 each independently represents a hydrogen atom, an alkyl group, or an aryl group. <5> 2. The iridium complex according to 1 above, wherein ring A is represented by the following general formula (5): [ka] (In the general formula (5), N represents a nitrogen atom. R 23 ~R 26 each independently represents a hydrogen atom, an alkyl group, or an aryl group. <6> R 1 , R 2 and R 3 6. The iridium complex according to any one of 1 to 5 above, wherein is a hydrogen atom. <7> X 1 C(R 6 7. The iridium complex according to any one of 1 to 6 above, <8> 8. The iridium complex according to any one of 1 to 7 above, wherein L is an aromatic heterocyclic bidentate ligand or a β-diketone ligand. <9> 8. The iridium complex according to any one of 1 to 7 above, wherein m=3 and n=0. <10> 9. The iridium complex according to any one of 1 to 8 above, wherein m=2 and n=1. <11> 11. A light-emitting material comprising the iridium complex according to any one of 1 to 10 above. <12> 12. A light-emitting element comprising the light-emitting material described in 11 above. Effect of the Invention

[0014] The novel iridium complex of the present invention exhibits strong light emission in the visible light region (especially in the green to red region) at room temperature, and therefore can be suitably used as a light-emitting material for various applications. Furthermore, a light-emitting element using the compound exhibits sharp light emission with a narrow half-width, and therefore is suitable for display applications. [Brief description of the drawings]

[0015] [Figure 1] 1 is an emission spectrum of the compound of the present invention (Ir-4) in toluene at room temperature. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these descriptions. Various modifications of the embodiments may be made as long as the effects of the present invention are achieved.

[0017] In the description of the general formula of the present invention, the hydrogen atoms include their isotopes (deuterium atoms, etc.), and further, the atoms constituting the substituents include their isotopes.

[0018] First, the symbols (Ir, N, C, X 1 , X 2 , X 3 , R 1 ~R 26 , rings A, L, m, n) are explained below.

[0019] Ir represents an iridium atom, N represents a nitrogen atom, and C represents a carbon atom.

[0020] X 1 is N or C(R 6 ), and C(R 6 ) is preferred.

[0021] X 2 is N or C(R 12 ) stands for X. 3 is N or C(R 13 ) where X 2 When N, X 3 is C(R 13 ), and X 2 C(R 12 ) when X 3 is N. Among them, X 2 C(R 12 ), and X 3 is preferably N.

[0022] R 1 , R 2 and R 3 R each independently represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom. 2 and R 3 is particularly preferably a hydrogen atom, since this narrows the half-width of the emission of the iridium complex of the present invention represented by general formula (1).

[0023] R 4 and R 5 Each of R independently represents an alkyl group. Among them, a branched alkyl group is preferable. Specifically, an iso-propyl group or a t-butyl group is more preferable, and a t-butyl group is particularly preferable. In addition, R 4 and R 5 may be the same or different, and are preferably the same.

[0024] R 4 and R 5When R is an alkyl group (preferably a branched alkyl group), the steric hindrance can suppress side reactions. For example, when ring A is a triazole ring, R 4 and R 5 When R is a t-butyl group, as shown in the following (Chemical formula 8), iridium can be coordinated to the triazole ring, but it is difficult for it to be coordinated to the triazine ring due to the steric hindrance of the branched alkyl group. 4 and R 5 is more preferably an alkyl group, preferably a branched alkyl group, since this significantly improves the synthesis yield of the iridium complex represented by general formula (1) of the present invention. [ka]

[0025] On the other hand, R 4 and R 5 When is an aryl group (e.g., a phenyl group), as shown in the following (Chemical Formula 9 to Chemical Formula 11), iridium can be coordinated with a triazine ring, and the synthesis yield of the desired iridium complex represented by general formula (1) is significantly reduced, which is not preferable. [ka] [ka] [ka]

[0026] R 6 represents a hydrogen atom or an alkyl group, of which a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0027] R 7 and R 11each independently represents a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, more preferably an alkyl group, particularly preferably an isopropyl group or a methyl group, and most preferably a methyl group.

[0028] R 8 and R 10 each independently represents a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.

[0029] R 9 each independently represents a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

[0030] R 12 and R 13 R each independently represents an alkyl group or an aryl group, preferably an alkyl group, and particularly preferably a methyl group. 12 or R 13 When the alkyl group is an alkyl group, the nitrogen atom (coordination-free nitrogen) that is not coordinated with iridium, among the two nitrogen atoms not bonded to the phenyl group on the triazole ring, is protected. This structural feature makes it possible to suppress the oxidation of the coordination-free nitrogen by oxygen, etc., and the formation of a coordinate bond between the coordination-free nitrogen and iridium, and the desired iridium complex represented by general formula (1) can be obtained in good yield. Furthermore, the thermal stability of the iridium complex is improved.

[0031] R 14 represents an alkyl group or an aryl group, preferably an alkyl group, and particularly preferably a methyl group.

[0032] R 15 and R 16 each independently represents a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.

[0033] R 17 ~R 26 each independently represents a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

[0034] Ring A represents a pyridine ring, a pyrimidine ring, a pyrazine ring, a quinoline ring, an isoquinoline ring, a pyrazole ring, an imidazole ring, or a triazole ring. When ring A is a pyrazole ring or a triazole ring, the compound of the present invention exhibits green light emission with a narrow half-width and excellent color purity, and is more preferably a triazole ring. When ring A is a quinoline ring or an isoquinoline ring, the compound of the present invention exhibits red light emission with a narrow half-width and excellent color purity, and is more preferably a quinoline ring.

[0035] Specific examples of the ring A that are desirable are represented by the general formulae (2) to (5). [ka]

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] When ring A is a triazole ring, the iridium complex represented by general formula (1) is preferably represented by general formula (8), more preferably represented by general formula (9) or general formula (10), and particularly preferably represented by general formula (9).

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] When ring A is a pyrazole ring, the iridium complex of the present invention represented by general formula (1) is preferably represented by general formula (11).

[0044] [ka]

[0045] When ring A is a quinoline ring, the iridium complex of the present invention represented by general formula (1) is preferably represented by general formula (12).

[0046] [ka]

[0047] When ring A is a pyridine ring, the iridium complex of the present invention represented by general formula (1) is preferably represented by general formula (13).

[0048] [ka]

[0049] When ring A is a pyrimidine ring, the iridium complex of the present invention represented by general formula (1) is preferably represented by general formula (14) or general formula (15).

[0050] [ka]

[0051] [ka]

[0052] When ring A is a pyrazine ring, the iridium complex of the present invention represented by general formula (1) is preferably represented by general formula (16).

[0053] [ka]

[0054] When ring A is an isoquinoline ring, the iridium complex of the present invention represented by general formula (1) is preferably represented by general formula (17).

[0055] [ka]

[0056] When ring A is an imidazole ring, the iridium complex represented by general formula (1) is preferably represented by general formula (18).

[0057] [ka]

[0058] The symbols (Ir, N, C, X 1 , X 2 , X 3 , R 1 ~R 26 , ring A, L, m, and n) have the same meanings as those described in formulae (1) to (5), and the preferred ranges are also the same.

[0059] R 27 ~R 43each independently represents a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

[0060] Also adjacent R 1 ~R 43 may be bonded to form a ring structure. The ring structure is preferably a saturated carbocyclic ring or an unsaturated carbocyclic ring, more preferably an unsaturated carbocyclic ring, and particularly preferably a benzene ring. The ring structure may be substituted with an alkyl group or an aryl group.

[0061] L represents an anionic bidentate ligand. Among the anionic bidentate ligands, aromatic heterocyclic bidentate ligands or β-diketone ligands are preferred, and aromatic heterocyclic bidentate ligands are more preferred. As the aromatic heterocyclic bidentate ligand, 2-phenylpyridine, 2-phenylimidazole, 5-phenyl-1,2,4-triazole, 3-phenyl-1,2,4-triazole, 3-phenylpyrazole, 2-phenylpyrimidine, 2-phenylquinoline, 1-phenylisoquinoline, or imidazo[1,2-f]phenanthridine are preferred, and 2-phenylpyridine, 5-phenyl-1,2,4-triazole, 3-phenylpyrazole, or 2-phenylquinoline are more preferred. As the β-diketone ligand, 2,4-pentanedione, 2,6-dimethyl-3,5-heptanedione, and 2,2,6,6-tetramethyl-3,5-heptanedione are preferred, and 2,4-pentanedione is more preferred. When a plurality of L's are present, they may be the same or different.

[0062] The anionic bidentate ligand may have a substituent. The substituent may be an alkyl group, an aryl group, an alkylsilyl group, a heterocyclic group, an alkoxy group, an aryloxy group, a cyano group, or a halogen atom, preferably an alkyl group, an aryl group, an alkylsilyl group, a heterocyclic group, a cyano group, or a halogen atom, more preferably an alkyl group, an aryl group, or a halogen atom, and particularly preferably an alkyl group or an aryl group.

[0063] It is also preferable that L is selected from any of the following general formulae (A) to (D). [ka] Symbols in general formulas (A) to (D), N, X 2 , X 3 , R 1 ~R 3 , R 7 ~R 11 , and R 14 ~R 26 is the same as the symbol in the general formulae (1) to (18). * represents a bonding site with iridium. R a R in general formulas (1) to (18) 17 ~R 26 Similarly, represents a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

[0064] m represents 1 to 3, preferably m=2 or 3, and more preferably m=3. n represents 0 to 2, preferably n=0 or 1, and more preferably n=0. However, m+n=3. Since the half width of the emission spectrum of the iridium complex represented by the general formula (1) of the present invention tends to be narrower when m=3, it is particularly preferred when m=2.

[0065] In this specification, the alkyl group may be substituted with at least one selected from an aryl group, an alkylsilyl group, a heterocyclic group, an alkoxy group, an aryloxy group, or a halogen atom, and may be further substituted with these substituents.

[0066] In this specification, the aryl group may be substituted with at least one selected from an alkyl group, an aryl group, an alkylsilyl group, a heterocyclic group, an alkoxy group, an aryloxy group, a cyano group, or a halogen atom, and may be further substituted with these substituents.

[0067] In this specification, the alkyl group preferably has 1 to 30 carbon atoms, not including the carbon number of substituents, more preferably has 1 to 20 carbon atoms, particularly preferably has 1 to 10 carbon atoms, and more particularly preferably has 1 to 6 carbon atoms.

[0068] As used herein, the alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a s-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, a neopentyl group, or a methyl group. group, 1-methylpentyl group, 1-pentylhexyl group, 1-butylpentyl group, 1-heptyloctyl group, cyclohexyl group, cyclooctyl group, or 3,5-tetramethylcyclohexyl group, more preferably methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, neopentyl group, or 1-methylpentyl group, and particularly preferably methyl group.

[0069] In this specification, the aryl group preferably has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and more particularly preferably 6 to 12 carbon atoms, not including the number of carbon atoms of substituents.

[0070] As the aryl group in the present specification, preferred are a phenyl group, a biphenyl-2-yl group, a biphenyl-3-yl group, a biphenyl-4-yl group, a p-terphenyl-4-yl group, a p-terphenyl-3-yl group, a p-terphenyl-2-yl group, a m-terphenyl-4-yl group, a m-terphenyl-3-yl group, a m-terphenyl-2-yl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a pt-butylphenyl group, a p-(2-phenylpropyl)phenyl group, a 4'-methylbiphenylyl group, a 4"-t-butyl-p-terphenyl-4-yl group, an o-chlorophenyl ... The alkyl group is preferably a phenyl group, an m-tolyl group, a p-cumenyl group, a 2,3-xylyl group, a 2,4-xylyl group, a 2,5-xylyl group, a 2,6-xylyl group, a 3,4-xylyl group, a 3,5-xylyl group, a mesityl group, an m-quarterphenyl group, a 1-naphthyl group, or a 2-naphthyl group, more preferably a phenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a 2,3-xylyl group, a 2,4-xylyl group, a 2,5-xylyl group, a 2,6-xylyl group, a 3,4-xylyl group, a 3,5-xylyl group, or a mesityl group, and particularly preferably a phenyl group.

[0071] The iridium complex represented by the general formula (1) according to the present invention will be described in more detail below.

[0072] The iridium complex represented by the general formula (1) according to the present invention is an octahedral 6-coordinate complex, and may exist as facial isomers and meridional isomers as geometric isomers.

[0073] When facial and meridional isomers exist as geometric isomers, the iridium complex represented by the general formula (1) according to the present invention is preferably a facial isomer. The iridium complex according to the present invention preferably contains 50% or more of facial isomers, more preferably 80% or more, particularly preferably 90% or more, and even more particularly preferably 99% or more. The facial isomer or meridional isomer can be separated and purified using a method such as column chromatography or recrystallization, and can be identified by NMR, mass spectrometry, or X-ray crystal structure analysis. The content can be quantified by NMR or HPLC.

[0074] It is also preferred that the meridional isomer of the iridium complex represented by the general formula (1) according to the present invention, or a solution containing the meridional isomer, is irradiated with light to isomerize it to the facial isomer.

[0075] The iridium complex represented by general formula (1) according to the present invention can be synthesized with reference to known documents such as WO 2004 / 101707, WO 2016 / 006523, JP 2012-46479, and WO 2016 / 203350.

[0076] The iridium complex represented by the general formula (1) according to the present invention can be treated according to the usual post-treatment of a synthetic reaction, and then purified or not purified if necessary. As the post-treatment method, for example, extraction, cooling, crystallization by adding water or an organic solvent, or an operation of distilling off the solvent from the reaction mixture, etc. can be used alone or in combination. As the purification method, recrystallization, distillation, sublimation, column chromatography, etc. can be used alone or in combination.

[0077] By incorporating the iridium complex represented by the general formula (1) according to the present invention into the light-emitting layer of a light-emitting element or into a plurality of organic compound layers including the light-emitting layer by a vacuum deposition method, a spin coating method, or the like, a light-emitting element that exhibits sharp light emission with a narrow half-width in the visible light region can be obtained.

[0078] Representative examples of the iridium complexes represented by general formula (1) according to the present invention are shown in Tables 1 to 7 below, but the present invention is not limited to these.

[0079] [Table 1]

[0080] [Table 2]

[0081] [Table 3]

[0082] [Table 4]

[0083] [Table 5]

[0084] [Table 6]

[0085] [Table 7] EXAMPLES

[0086] The present invention will now be described in more detail with reference to examples, but the present invention is not limited thereto.

[0087] Example 1-1 (Synthesis of the present compound (Ir-4)) [ka] IrCl 3 nH 2 150.1 mg of O, 425.4 mg of ligand (L-4), 15 ml of 2-ethoxyethanol, and 4.6 ml of water were placed in a three-neck flask and heated under reflux for 24 hours under an argon atmosphere. After the reaction solution was cooled to room temperature, dichloromethane and water were added, followed by extraction and recovery of the organic layer. The organic layer was concentrated under reduced pressure, and the precipitated yellow solid was recrystallized using dichloromethane and hexane to obtain 379.7 mg of intermediate (D-4). Subsequently, 122.0 mg of intermediate (D-4), 150.0 mg of ligand (L-4), 37.4 mg of silver trifluoromethanesulfonate, and 1 ml of diethylene glycol dimethyl ether (diglyme) were placed in a Schlenk flask and reacted at 166°C for 66 hours under an argon atmosphere. After cooling the reaction mixture to room temperature, dichloromethane was added and the mixture was filtered through a Celite layer. The filtrate was dried under reduced pressure, and the precipitated solid was separated and purified by silica gel chromatography (mobile phase: mixed solvent of ethyl acetate and hexane) to obtain 95.9 mg of the compound of the present invention (Ir-4). The compound of the present invention (Ir-4) obtained was a facial form.

[0088] The compound of the present invention (Ir-4) 1 The H-NMR data is shown below. 1 H-NMR (400MHz / Acetone-d 6 ):δ(ppm)7.92(d,3H),7.82(dd,3H),7.46(t,3H),7.42(d,3H),7.22(d,3H),7 .07(s,3H),6.52(d,3H),2.27(s,9H),2.25(s,9H),1.70(s,9H),1.12(s,54H).

[0089] Example 1-2 (Synthesis of the compound of the present invention (Ir-3)) [ka] IrCl 3 nH 2 75.5 mg of O, 204.6 mg of ligand (L-3), 7 ml of 2-ethoxyethanol, and 2.3 ml of water were placed in a three-neck flask and heated under reflux for 15 hours under an argon atmosphere. After the reaction solution was cooled to room temperature, dichloromethane and water were added, followed by extraction and recovery of the organic layer. The organic layer was concentrated under reduced pressure, and the precipitated yellow solid was recrystallized using dichloromethane and hexane to obtain 214.9 mg of intermediate (D-3). Subsequently, 123.0 mg of intermediate (D-3), 150 mg of ligand (L-3), 37.4 mg of silver trifluoromethanesulfonate, and 0.5 ml of diethylene glycol dimethyl ether (diglyme) were placed in a Schlenk flask and reacted at 166°C for 66 hours under an argon atmosphere. After cooling the reaction mixture to room temperature, dichloromethane was added and the mixture was filtered through a Celite layer. The filtrate was dried under reduced pressure, and the precipitated solid was separated and purified by silica gel chromatography (mobile phase: mixed solvent of ethyl acetate and hexane) to obtain 100.3 mg of the compound of the present invention (Ir-3). The compound of the present invention (Ir-3) obtained was a facial form.

[0090] The compound of the present invention (Ir-3) 1 The H-NMR data is shown below. 1 H-NMR (400MHz / Acetone-d 6 ):δ(ppm)7.82-7.84(m,6H),7.50(t,3H),7.44(d,3H),7.27(d,3H),6.55(d,3H),2.27(s,9H),2.26(s,9H),1.70(s,9H),1.17(s,54H).

[0091] Example 1-3 (Synthesis of the compound of the present invention (Ir-27)) [ka] 10.0 mg of iridium acetate, 35.1 mg of ligand (L-27), and 1 ml of diethylene glycol were placed in a three-neck flask and reacted at 150°C for 15 hours under an argon atmosphere. After the reaction solution was cooled to room temperature, the precipitated solid was washed with methanol. This solid was separated and purified by silica gel chromatography (mobile phase: mixed solvent of ethyl acetate and hexane) to obtain 3 mg of the compound of the present invention (Ir-27). The compound of the present invention (Ir-27) obtained was a facial form.

[0092] The compound of the present invention (Ir-27) 1 The H-NMR data is shown below. 1 H-NMR (400MHz / CD 2 Cl 2 ):δ(ppm)8.31(d,3H),8.14(dd,3H),8.04(d,3H),7.79(d,3H),7.71(dd,3H),7.69(d,3H),7.03(dd,3H),1.12(s,54H).

[0093] Example 1-4 (Synthesis of the compound of the present invention (Ir-28)) [ka] 10.0 mg of iridium acetate, 35.1 mg of ligand (L-28), and 1 ml of diethylene glycol were placed in a three-neck flask and reacted under argon atmosphere at 150°C for 15 hours. After cooling the reaction solution to room temperature, the precipitated solid was washed with methanol. This solid was separated and purified by silica gel chromatography (mobile phase: mixed solvent of ethyl acetate and hexane) to obtain 4 mg of the compound of the present invention (Ir-28). The compound of the present invention (Ir-28) obtained was a facial form.

[0094] The compound of the present invention (Ir-28) 1 The H-NMR data is shown below. 1 H-NMR (400MHz / CD 2 Cl 2):δ(ppm)8.29(brs,3H),8.12(d,3H),8.00(d,3H),7.76(d,3H),7.66-7.70(m,6H),6.98(dd,3H),6.94(s,3H),1.08(s,54H).

[0095] Examples 1-5 (Synthesis of the compound of the present invention (Ir-35)) [ka] 51.7 mg of iridium chloride trihydrate, 1.41 g of ligand (L-35), and 3 ml of diethylene glycol were placed in a recovery flask and irradiated with 500 W microwaves (2450 Hz) for 35 minutes under a nitrogen atmosphere. After cooling the reaction solution to room temperature, water was added and the precipitated solid was washed with methanol. This solid was separated and purified by silica gel chromatography (mobile phase: mixed solvent of dichloromethane and hexane) to obtain 3 mg of the compound of the present invention (Ir-35). The compound of the present invention (Ir-35) obtained was a facial form.

[0096] The compound of the present invention (Ir-35) 1 The H-NMR data is shown below. 1 H-NMR (400MHz / Acetone-d 6 ):δ(ppm)8.19(d,3H),8.16(d,3H),8.09(d,3H),8.08(dd,3H),7.89(d,3H),7.78(d,3H),7.68(dd,3H),7.21(m,3H),6.75(m,3H),1.23(s,54H).

[0097] Examples 1-6 (Synthesis of the compound of the present invention (Ir-38)) [ka] IrCl 3 nH 2 180.3 mg of O, 503.3 mg of ligand (L-35), and 10 ml of 2-ethoxyethanol were placed in a recovery flask and heated under reflux for 24 hours under a nitrogen atmosphere. After the reaction solution was cooled to room temperature, water was added and the precipitate containing intermediate (D-35) was collected. Subsequently, 614.5 mg of precipitate containing intermediate (D-35), 77.4 mg of acetylacetone, 81.1 mg of sodium carbonate, and 10 ml of 2-ethoxyethanol were placed in a recovery flask and reacted under nitrogen atmosphere at 90°C for 4 hours. After cooling the reaction mixture to room temperature, water was added and the precipitated solid was collected. The obtained solid was separated and purified by silica gel chromatography (mobile phase: toluene) to obtain 147 mg of the present compound (Ir-38).

[0098] The compound of the present invention (Ir-38) 1 The H-NMR data is shown below. 1 H-NMR (400MHz / Acetone-d 6 ):δ(ppm)8.72(d,2H),8.56(d,2H),8.48(d,2H),8.13(d,2H),8.07(m,4H),7. 78(d,2H),7.76(td,2H),7.55(m,2H),4.88(s,1H),1.55(s,6H),1.12(s,36H).

[0099] Example 1-7 (Synthesis of the compound of the present invention (Ir-79)) [ka] 33.5 mg of iridium chloride trihydrate, 150 mg of ligand (L-79), and 3 ml of ethylene glycol were placed in a recovery flask and reacted at 200°C for 2 hours under a nitrogen atmosphere. After the reaction solution was cooled to room temperature, water was added and the precipitated solid was washed with methanol. This solid was separated and purified by silica gel chromatography (mobile phase: dichloromethane) to obtain 6 mg of the compound of the present invention (Ir-79). The compound of the present invention (Ir-79) obtained was a facial form.

[0100] The compound of the present invention (Ir-79) 1 The H-NMR data is shown below. 1 H-NMR (400MHz / CDCl 3):δ(ppm)8.13(dd,3H),8.06(d,3H),7.46(d,3H),7.24(d,3H),6.55(d,3H),3.27(s,3H),1.12(s,54H).

[0101] Example 1-8 (Synthesis of the compound of the present invention (Ir-88)) [ka] Compound (D-88) 202.7 mg, silver trifluoromethanesulfonate 80.5 mg, dichloromethane 10 ml, and methanol 0.6 ml were placed in a three-neck flask and stirred at room temperature under an argon atmosphere for 65 hours. The reaction solution was filtered through a Celite layer, and the filtrate was concentrated under reduced pressure to obtain intermediate (I-88). Subsequently, the entire amount of the intermediate (I-88) obtained above, 301 mg of the ligand (L-88), and 6 ml of ethanol were placed in a Schlenk flask, and the mixture was heated and reacted at 90° C. for 187 hours under an argon atmosphere. The mixture was cooled to room temperature, the precipitated solid was filtered, and recrystallized using dichloromethane and hexane to obtain the compound of the present invention (Ir-88). The reaction solution was distilled under reduced pressure, 3 ml of ethanol was added to the mixture, and the mixture was heated under reflux for 25 days under an argon atmosphere. The mixture was cooled to room temperature, and the precipitated solid was collected by suction filtration. The solid was isolated and purified by silica gel column chromatography (eluent: a mixed solvent of dichloromethane and ethyl acetate), and further recrystallized using dichloromethane and hexane. A total of 236.6 mg of the compound of the present invention (Ir-88) was obtained.

[0102] The compound of the present invention (Ir-88) 1 The H-NMR data is shown below. 1 H-NMR (400MHz / Acetone-d 6):δ(ppm)7.91(dd,1H),7.81(dd,1H),7.32-7.52(m,8H),7.20(s,1H),7.15(d,1H),6.52-6.66(m,6H),6.48(d,1H),6.42(s, 1H),6.40(s,1H),2.23(s,3H),2.21(s,6H),2.16(s,6H),2.15(s,3H),1.84(s,3H),1.83(s,3H),1.54(s,3H),1.20(s,18H).

[0103] Next, the luminescence characteristics of the iridium complex of the present invention will be described. Example 2-1 (Emission of the compound of the present invention (Ir-27) in toluene) The compound of the present invention (Ir-27) was dissolved in toluene, and argon gas was passed through the solution. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics KK, and orange light was emitted (maximum emission wavelength: 562 nm). The full width at half maximum (FWHM) of the emission spectrum was 37 nm.

[0104] Example 2-2 (Emission of the compound of the present invention (Ir-28) in toluene) The compound of the present invention (Ir-28) was dissolved in toluene, and argon gas was passed through the solution. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics KK, and yellow light was emitted (maximum emission wavelength: 549 nm). The full width at half maximum (FWHM) of the emission spectrum was 33 nm.

[0105] Comparative Example 2-1 (Emission of Comparative Compound (A) in Toluene) [ka] Comparative compound (A) was dissolved in toluene and argon gas was passed through it. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. The emission spectrum showed green light emission (maximum emission wavelength: 510 nm). The full width at half maximum (FWHM) was 66 nm.

[0106] Comparative Example 2-2 (Emission of Comparative Compound (B) in Toluene) [ka] Comparative compound (B) was dissolved in toluene and argon gas was passed through it. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. The emission spectrum showed yellow-green emission (maximum emission wavelength: 531 nm). The full width at half maximum (FWHM) was 63 nm.

[0107] Comparative Example 2-3 (Emission of Comparative Compound (C) in Toluene) [ka] The comparative compound (C) disclosed in JP 2011-121876 A was dissolved in toluene, and argon gas was passed through it. The emission spectrum (excitation wavelength: 350 nm) at room temperature was measured using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. The emission spectrum showed blue-green light emission (maximum emission wavelength: 492 nm). The full width at half maximum (FWHM) was 54 nm.

[0108] When comparing the emission characteristics of the compounds described in the Examples and Comparative Examples, the emission half width of the compounds of the present invention is 33 to 37 nm, while the emission half width of the comparative compounds is 54 to 66 nm, so that it is clear that the compounds of the present invention show excellent emission characteristics with a narrower half width. Furthermore, when comparing the compounds of the present invention and the comparative compound (A), it is clear that the emission wavelength is shifted to a longer wavelength by 39 to 52 nm due to the effect of the substituent represented by the general formula (7). Furthermore, as in the case of the comparative compound (C), when the position of the substituent introduced is changed, the emission wavelength is shifted to a shorter wavelength, which is the opposite effect to the present invention. Furthermore, when comparing the compounds of the present invention (Ir-27) and (Ir-28), (Ir-28) shows excellent emission with a narrower emission half width, so that it is clear that the compound represented by X in the general formula (1) has a narrower emission half width. 1 C(R 6 ) was found to be preferable.

[0109] Example 2-3 (Emission of the compound of the present invention (Ir-4) in toluene) The compound of the present invention (Ir-4) was dissolved in toluene, and argon gas was passed through the solution. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics KK, and green light was emitted (maximum emission wavelength: 518 nm). The full width at half maximum (FWHM) of the emission spectrum was 24 nm.

[0110] Example 2-4 (Emission of the compound of the present invention (Ir-3) in toluene) The compound of the present invention (Ir-3) was dissolved in toluene, and argon gas was passed through the solution. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics KK, and green light was emitted (maximum emission wavelength: 538 nm). The full width at half maximum (FWHM) of the emission spectrum was 30 nm.

[0111] Comparative Example 2-4 (Emission of Comparative Compound (D) in Toluene) [ka] Comparative compound (D) was dissolved in toluene and argon gas was passed through it. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. The emission spectrum showed blue light emission (maximum emission wavelength: 456 nm). The full width at half maximum (FWHM) was 51 nm.

[0112] Here, when comparing the emission characteristics of the compounds described in Examples 2-3, 2-4, and Comparative Example 2-4, it was found that the half-width of the emission spectrum of the compound of the present invention is 24 to 30 nm, while the half-width of the emission spectrum of the comparative compound is 51 nm, so that the compound of the present invention exhibits excellent emission with a narrower half-width. Furthermore, when comparing Examples 2-1 to 2-4, it was found that the half-width is narrower when the ring A in the general formula (1) is a triazole ring than when it is a pyridine ring. In other words, it was found that the effect of the present invention is particularly remarkable.

[0113] Example 2-5 (Emission of the compound of the present invention (Ir-79) in toluene) The compound of the present invention (Ir-79) was dissolved in toluene, and argon gas was passed through the solution. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics KK, and green light was emitted (maximum emission wavelength: 518 nm). The full width at half maximum (FWHM) of the emission spectrum was 66 nm.

[0114] Comparative Example 2-5 (Emission of Comparative Compound (E) in Toluene) [ka] The comparative compound (E) was dissolved in toluene and argon gas was passed through the solution. The emission spectrum (excitation wavelength: 350 nm) at room temperature was measured using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. No emission was observed at all.

[0115] Example 2-6 (Emission of the compound of the present invention (Ir-35) in toluene) The compound of the present invention (Ir-35) was dissolved in toluene, and argon gas was passed through the solution. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. The emission spectrum showed red light emission (maximum emission wavelength: 609 nm). The full width at half maximum (FWHM) of the emission spectrum was 71 nm. The CIE chromaticity coordinates of the emission were (x, y) = (0.65, 0.35).

[0116] Example 2-7 (Emission of the compound of the present invention (Ir-38) in toluene) The compound of the present invention (Ir-38) was dissolved in toluene, and argon gas was passed through the solution. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. The emission spectrum showed red light emission (maximum emission wavelength: 628 nm). The full width at half maximum (FWHM) of the emission spectrum was 55 nm. The CIE chromaticity coordinates of the emission were (x, y) = (0.68, 0.31).

[0117] Comparative Example 2-6 (Emission of Comparative Compound (F) in Toluene) [ka] Comparative compound (F) was dissolved in toluene and argon gas was passed through it. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. The emission spectrum showed orange light emission (maximum emission wavelength: 583 nm). The full width at half maximum (FWHM) of the emission spectrum was 94 nm. The CIE chromaticity coordinates of the emission were (x, y) = (0.57, 0.43).

[0118] Comparative Example 2-7 (Emission of Comparative Compound (G) in Toluene) [ka] Comparative compound (G) was dissolved in toluene and argon gas was passed through it. The emission spectrum (excitation wavelength: 350 nm) was measured at room temperature using an absolute PL quantum yield measurement device (C9920) manufactured by Hamamatsu Photonics K.K. The emission spectrum showed red light emission (maximum emission wavelength: 601 nm). The full width at half maximum (FWHM) of the emission spectrum was 77 nm. The CIE chromaticity coordinates of the emission were (x, y) = (0.63, 0.37).

[0119] When comparing the luminescence characteristics of the compounds described in Example (2-5) and Comparative Example (2-5), it is clear that the compound of the present invention (Ir-79) is superior as a luminescent material, since the comparative compound (E) is non-luminescent at room temperature. In addition, when comparing the luminescence characteristics of the compounds described in Examples (2-6) to (2-7) and Comparative Examples (2-6) to (2-7), the compounds of the present invention have narrower half-widths of luminescence than the comparative compounds, and the CIE chromaticity coordinates of the luminescence show good values. In other words, it is clear that the compounds of the present invention (Ir-35) and (Ir-38) exhibit red luminescence with excellent color purity.

Claims

1. 1. An iridium complex represented by the following general formula (1): 【Chemistry 1】 (In general formula (1), Ir represents an iridium atom, N represents a nitrogen atom, and ring A represents a pyridine ring, a quinoline ring, a pyrazole ring, or a triazole ring. R １ , R ２ and R ３ represents a hydrogen atom. １ is N or C(R ６ ) represents R ４ and R ５ Each independently represents a branched alkyl group. ６ represents a hydrogen atom. L represents an anionic bidentate ligand. When a plurality of L's are present, they may be the same or different. m represents 1 to 3, and n represents 0 to 2, provided that m+n=3.

2. 2. The iridium complex according to claim 1, wherein ring A is represented by the following general formula (2): 【Chemistry 2】 (In the general formula (2), N represents a nitrogen atom. X ２ is C(R １２ ) represents X ３ represents N. ７ ~R １１ Each independently represents a hydrogen atom, an alkyl group, or an aryl group. R12 represents an alkyl group or an aryl group.

3. 2. The iridium complex according to claim 1, wherein ring A is represented by the following general formula (3): 【Chemistry 3】 (In the general formula (3), N represents a nitrogen atom. R １４ represents an alkyl group. １５ and R １６ each independently represents a hydrogen atom, an alkyl group, or an aryl group.

4. 2. The iridium complex according to claim 1, wherein ring A is represented by the following general formula (4): 【Chemistry 4】 (In the general formula (4), N represents a nitrogen atom. R １７ ~R ２２ each independently represents a hydrogen atom, an alkyl group, or an aryl group.

5. 2. The iridium complex according to claim 1, wherein ring A is represented by the following general formula (5): 【Chemistry 5】 (In the general formula (5), N represents a nitrogen atom. R ２３ ~R ２６ each independently represents a hydrogen atom, an alkyl group, or an aryl group.

6. X １ C(R ６ 6. The iridium complex according to claim 1, wherein

7. 7. The iridium complex according to claim 1, wherein L is an aromatic heterocyclic bidentate ligand or a β-diketone ligand.

8. 7. The iridium complex according to claim 1, wherein m=3 and n=0.

9. 8. The iridium complex according to claim 1, wherein m=2 and n=1.

10. A light-emitting material comprising the iridium complex according to any one of claims 1 to 9.

11. A light-emitting device comprising the luminescent material according to claim 10.

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