JP7656887B2 - Iridium complex and light-emitting material comprising said compound - Google Patents

Description

The present invention relates to an iridium complex that is suitable for use as a light-emitting material in organic electroluminescent devices and the like.

Organic electroluminescent elements have attracted 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 elements 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 elements, 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.

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).

Special table 2003-526876 Patent Publication 2011-121876

NHK Research Institute R&D, 2017, No. 164, pp. 68-74.

The iridium complexes having phenylpyridine ligands described in Patent Documents 1 and 2 emit green light, but have a problem in that the emission spectrum is broad and has poor color purity. 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).

The 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 (especially the green to red region) and a light-emitting material using said compound.

In view of the above situation, the inventors have conducted extensive research into the relationship between the structure and luminescence properties of iridium complexes. As a result, they 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 led to the successful development of an iridium complex that emits light with a narrow half-width in the visible light region (especially the green to red region), which was previously difficult to achieve, and thus to the completion of the present invention. The above experimental facts were completely unknown in the past, and are new findings obtained by the inventors through numerous meticulous experiments.

（一般式（６）と（７）中、Ｉｒ、Ｎ、環Ａ、Ｘ^１、Ｒ^１～Ｒ^５は、後述する一般式（１）中のＩｒ、Ｎ、環Ａ、Ｘ^１、Ｒ^１～Ｒ^５と同一である。＊は一般式（６）との結合部位である。）

(In general formulas (6) and (7), Ir, N, ring A, X ¹ , and R ¹ to R ⁵ are the same as Ir, N, ring A, X ¹ , and R ¹ to R ⁵ in general formula (1) described below. * indicates the bonding site with general formula (6).)

In other words, this application provides the following invention:

（一般式（１）中、Ｉｒはイリジウム原子を表し、Ｎは窒素原子を表す。環Ａは、ピリジン環、ピリミジン環、ピラジン環、キノリン環、イソキノリン環、ピラゾール環、イミダゾール環、または、トリアゾール環を表す。Ｒ^１、Ｒ^２およびＲ^３は、各々独立に、水素原子、または、アルキル基を表す。Ｘ^１は、ＮまたはＣ（Ｒ^６）を表す。Ｒ^４およびＲ^５は、各々独立に、アルキル基を表す。Ｒ^６は、水素原子またはアルキル基を表す。Ｌはアニオン性２座配位子を表す。Ｌが複数存在するときは、各々、同一でも異なっても良い。ｍ＝１～３を表し、ｎ＝０～２を表す。但し、ｍ＋ｎ＝３である。）
＜２＞環Ａが、下記一般式（２）で表されることを特徴とする、前記１に記載のイリジウム錯体。

（一般式（２）中、Ｎは窒素原子を表す。Ｘ^２はＮまたはＣ（Ｒ^１２）を表す。Ｘ^３はＮまたはＣ（Ｒ^１３）を表す。但し、Ｘ^２がＮのときＸ^３はＣ（Ｒ^１３）であり、Ｘ^２がＣ（Ｒ^１２）のときＸ^３はＮである。Ｒ^７～Ｒ^１１は、各々独立に、水素原子、アルキル基、または、アリール基を表す。Ｒ^１２とＲ^１３は、各々独立に、アルキル基、または、アリール基を表す。）
＜３＞環Ａが、下記一般式（３）で表されることを特徴とする、前記１に記載のイリジウム錯体。

（一般式（３）中、Ｎは窒素原子を表す。Ｒ^１４は、アルキル基、または、アリール基を表す。Ｒ^１５とＲ^１６は、各々独立に、水素原子、アルキル基、または、アリール基を表す。）
＜４＞環Ａが、下記一般式（４）で表されることを特徴とする、前記１に記載のイリジウム錯体。

（一般式（４）中、Ｎは窒素原子を表す。Ｒ^１７～Ｒ^２２は、各々独立に、水素原子、アルキル基、または、アリール基を表す。）
＜５＞環Ａが、下記一般式（５）で表されることを特徴とする、前記１に記載のイリジウム錯体。

（一般式（５）中、Ｎは窒素原子を表す。Ｒ^２３～Ｒ^２６は、各々独立に、水素原子、アルキル基、または、アリール基を表す。）
＜６＞Ｒ^１、Ｒ^２およびＲ^３が、水素原子であることを特徴とする、前記１～５の何れかに記載のイリジウム錯体。
＜７＞Ｘ^１がＣ（Ｒ^６）であることを特徴とする、前記１～６の何れかに記載のイリジウム錯体。
＜８＞Ｌが芳香族複素環２座配位子またはβ－ジケトン配位子であることを特徴とする、前記１～７の何れかに記載のイリジウム錯体。
＜９＞ｍ＝３、ｎ＝０であることを特徴とする、前記１～７の何れかに記載のイリジウム錯体。
＜１０＞ｍ＝２、ｎ＝１であることを特徴とする、前記１～８の何れかに記載のイリジウム錯体。
＜１１＞前記１～１０の何れかに記載のイリジウム錯体を含むことを特徴とする、発光材料。
＜１２＞前記１１に記載の発光材料を含むことを特徴とする、発光素子。 <1> An iridium complex represented by the following general formula (1):

(In general formula (1), Ir represents an iridium atom, and N represents a nitrogen atom. 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 independently represent a hydrogen atom or an alkyl group. X ¹ represents N or C(R ⁶ ). ^{R 4} and R ⁵ each independently represent an alkyl group. R ⁶ represents a hydrogen atom or an alkyl group. L represents an anionic bidentate ligand. When a plurality of Ls 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> The iridium complex according to item 1 above, wherein ring A is represented by the following general formula (2):

(In general formula (2), N represents a nitrogen atom. ^X2 represents N or C( ^R12 ). ^X3 represents N or C( ^R13 ). However, when ^X2 is N, ^X3 is C( ^R13 ), and when ^X2 is C( ^R12 ), ^X3 is N. ^R7 to ^R11 each independently represent a hydrogen atom, an alkyl group, or an aryl group. ^R12 and ^R13 each independently represent an alkyl group or an aryl group.)
<3> The iridium complex according to item 1 above, wherein ring A is represented by the following general formula (3):

(In general formula (3), N represents a nitrogen atom. R ¹⁴ represents an alkyl group or an aryl group. R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, an alkyl group, or an aryl group.)
<4> The iridium complex according to item 1 above, wherein ring A is represented by the following general formula (4):

(In formula (4), N represents a nitrogen atom. R ¹⁷ to R ²² each independently represent a hydrogen atom, an alkyl group, or an aryl group.)
<5> The iridium complex according to item 1 above, wherein ring A is represented by the following general formula (5):

(In formula (5), N represents a nitrogen atom. R ²³ to R ²⁶ each independently represent a hydrogen atom, an alkyl group, or an aryl group.)
<6> The iridium complex according to any one of the above items 1 to 5, wherein R ¹ , R ² and R ³ are hydrogen atoms.
<7> The iridium complex according to any one of the above items 1 to 6, wherein X ¹ is C(R ⁶ ).
<8> The iridium complex according to any one of the above items 1 to 7, wherein L is an aromatic heterocyclic bidentate ligand or a β-diketone ligand.
<9> The iridium complex according to any one of 1 to 7 above, wherein m=3 and n=0.
<10> The iridium complex according to any one of 1 to 8 above, wherein m=2 and n=1.
<11> A light-emitting material comprising the iridium complex according to any one of <1> to <10>.
<12> A light-emitting element comprising the light-emitting material according to <11>.

The novel iridium complex of the present invention exhibits strong emission in the visible light region (especially the green to red region) at room temperature, and can therefore be suitably used as a light-emitting material for a variety of applications. Furthermore, light-emitting elements using this compound exhibit sharp emission with a narrow half-width, making them suitable for display applications.

1 shows an emission spectrum of the compound (Ir-4) of the present invention in toluene at room temperature.

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

The hydrogen atoms in the description of the general formula of the present invention include isotopes (such as deuterium atoms), and furthermore, the atoms constituting the substituents also include their isotopes.

First, the symbols (Ir, N, C, ^X1 , ^X2 , ^X3 , ^R1 to ^R26 , ring A, L, m, and n) described in the general formulas (1) to (5) will be explained below.

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

X ¹ is N or C(R ⁶ ), and is preferably C(R ⁶ ).

^X2 represents N or C( ^R12 ). ^X3 represents N or C( ^R13 ). However, when ^X2 is N, ^X3 is C( ^R13 ), and when ^X2 is C( ^R12 ), ^X3 is N. Among them, it is preferable that ^X2 is C( ^R12 ) and ^X3 is N.

R ¹ , R ² and R ³ each independently represent a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom. It is particularly preferred that ^{R 2} and R ³ are hydrogen atoms, since this narrows the half-width of the emission of the iridium complex represented by the general formula (1) of the present invention.

R ⁴ and R ⁵ each independently represent 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. R ⁴ and R ⁵ may be the same or different, and are preferably the same.

When R ⁴ and R ⁵ are alkyl groups (preferably branched alkyl groups), the steric hindrance can suppress side reactions. For example, when ring A is a triazole ring and R ⁴ and R ⁵ are t-butyl groups, 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. Therefore, it is more preferable that R ⁴ and R ⁵ are alkyl groups, preferably branched alkyl groups, since this greatly improves the synthesis yield of the iridium complex represented by general formula (1) of the present invention.

On the other hand, when ^R4 and ^R5 are aryl groups (e.g., phenyl groups), as shown in the following (Chemical Formula 9 to Chemical Formula 11), iridium can be coordinated to a triazine ring, and this is not preferred because it significantly reduces the synthesis yield of the desired iridium complex represented by general formula (1).

^R6 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.

^R7 and ^R11 each independently represent 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.

^R8 and ^R10 each independently represent a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.

Each R ⁹ 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.

R ¹² and R ¹³ each independently represent an alkyl group or an aryl group, preferably an alkyl group, and particularly preferably a methyl group. When R ¹² or R ¹³ 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 can suppress the oxidation of the coordination-free nitrogen by oxygen or the like, 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.

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

R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, an alkyl group, or an aryl group, preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.

R ¹⁷ to R ²⁶ each independently represent 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.

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 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 preferably a quinoline ring.

Specific examples of the ring A that are preferable include those represented by the general formulae (2) to (5).

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).

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).

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).

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).

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).

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).

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).

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

The symbols (Ir, N, C, ^X1 , ^X2 , ^X3 , ^R1 to ^R26 , ring A, L, m, and n) described in general formulas (6) to (18) have the same meanings as the symbols described in general formulas (1) to (5), and the preferable ranges are also the same.

R ²⁷ to R ⁴³ each independently represent 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.

Adjacent R ¹ to 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.

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 aromatic heterocyclic bidentate ligands, 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 multiple Ls are present, they may be the same or different.

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. An alkyl group, an aryl group, an alkylsilyl group, a heterocyclic group, a cyano group, or a halogen atom is preferred, an alkyl group, an aryl group, or a halogen atom is more preferred, and an alkyl group or an aryl group is particularly preferred.

一般式（Ａ）～（Ｄ）中の記号、Ｎ、Ｘ^２、Ｘ^３、Ｒ^１～Ｒ^３、Ｒ^７～Ｒ^１１、および、Ｒ^１４～Ｒ^２６は、一般式（１）～（１８）中の記号と同じである。＊はイリジウムとの結合部位を表す。Ｒ^ａは、一般式（１）～（１８）中のＲ^１７～Ｒ^２６と同様に、水素原子、アルキル基、または、アリール基を表し、水素原子、または、アルキル基が好ましく、水素原子、または、メチル基がより好ましく、水素原子が特に好ましい。 It is also preferable that L is selected from any one of the following general formulas (A) to (D).

The symbols N, X ² , X ³ , R ¹ to R ³ , R ⁷ to R ¹¹ , and R ¹⁴ to R ²⁶ in the general formulae (A) to (D) are the same as the symbols in the general formulae (1) to (18). * represents a bonding site with iridium. ^{R a} , like R ¹⁷ to R ²⁶ in the general formulae (1) to (18), 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.

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. m = 3 is particularly preferred because the half-width of the emission spectrum of the iridium complex represented by general formula (1) of the present invention tends to be narrower than m = 2.

The alkyl group in this specification 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.

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.

In this specification, the alkyl group preferably has 1 to 30 carbon atoms, not including the carbon number of the substituent, 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.

As the alkyl group in this specification, 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, 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.

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

In the present specification, the aryl group is preferably 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 p-t-butylphenyl group, a p-(2-phenylpropyl)phenyl group, a 4'-methylbiphenylyl group, a 4"-t-butyl-p-terphenyl-4-yl group, an o-chlorophenyl group, a It is preferably a phenyl group, an m-cumenyl 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, an 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.

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

The iridium complex represented by the general formula (1) according to the present invention is an octahedral hexacoordinate complex, and in some cases, facial and meridional isomers exist as geometric isomers.

When facial and meridional isomers exist as geometric isomers, the iridium complex represented by 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 preferably 99% or more. The facial isomer or meridional isomer can be separated and purified using techniques 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.

It is also preferable to irradiate the meridional isomer of the iridium complex represented by general formula (1) according to the present invention, or a solution containing the meridional isomer, with light to isomerize it to the facial isomer.

The iridium complex represented by the 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.

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. The post-treatment method can be, for example, extraction, cooling, crystallization by adding water or an organic solvent, or an operation of distilling off the solvent from the reaction mixture, which can be performed alone or in combination. The purification method can be recrystallization, distillation, sublimation, or column chromatography, which can be performed alone or in combination.

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 multiple 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.

Representative examples of 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.

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

ＩｒＣｌ_３・ｎＨ_２Ｏ １５０．１ｍｇ、配位子（Ｌ－４）４２５．４ｍｇ、２－エトキシエタノール１５ｍｌ、水４．６ｍｌを三口フラスコに入れ、アルゴン雰囲気下、２４時間加熱還流させた。反応溶液を室温まで冷却後、ジクロロメタンと水を加えてから抽出し有機層を回収した。有機層を減圧濃縮し析出した黄色固体をジクロロメタンとヘキサンを用いて再結晶し、中間体（Ｄ－４）を３７９．７ｍｇ得た。
引き続いて、中間体（Ｄ－４）１２２．０ｍｇ、配位子（Ｌ－４）１５０．０ｍｇ、トリフルオロメタンスルホン酸銀３７．４ｍｇ、ジエチレングリコールジメチルエーテル（ジグライム）１ｍｌをシュレンク管に入れ、アルゴン雰囲気下、１６６℃で６６時間加熱反応させた。反応混合物を室温まで冷却後、ジクロロメタンを加えて、セライト層を通してろ過した。ろ液を減圧乾固し析出した固体をシリカゲルクロマトグラフィー（移動相：酢酸エチルとヘキサンの混合溶媒）で分離精製し、本発明化合物（Ｉｒ－４）を９５．９ｍｇ得た。得られた本発明化合物（Ｉｒ－４）はフェイシャル体であった。 Example 1-1 (Synthesis of the present compound (Ir-4))

150.1 mg of IrCl ₃ · nH ₂ 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 under heating 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.

^{The 1} H-NMR data of the compound of the present invention (Ir-4) is shown below.
^1H -NMR (400MHz/Acetone- _d6 ): 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).

ＩｒＣｌ_３・ｎＨ_２Ｏ ７５．５ｍｇ、配位子（Ｌ－３）２０４．６ｍｇ、２－エトキシエタノール７ｍｌ、水２．３ｍｌを三口フラスコに入れ、アルゴン雰囲気下、１５時間加熱還流させた。反応溶液を室温まで冷却後、ジクロロメタンと水を加えてから抽出し有機層を回収した。有機層を減圧濃縮し析出した黄色固体をジクロロメタンとヘキサンを用いて再結晶し、中間体（Ｄ－３）を２１４．９ｍｇ得た。
引き続いて、中間体（Ｄ－３）１２３．０ｍｇ、配位子（Ｌ－３）１５０ｍｇ、トリフルオロメタンスルホン酸銀３７．４ｍｇ、ジエチレングリコールジメチルエーテル（ジグライム）０．５ｍｌをシュレンク管に入れ、アルゴン雰囲気下、１６６℃で６６時間加熱反応させた。反応混合物を室温まで冷却後、ジクロロメタンを加えて、セライト層を通してろ過した。ろ液を減圧乾固し析出した固体をシリカゲルクロマトグラフィー（移動相：酢酸エチルとヘキサンの混合溶媒）で分離精製し、本発明化合物（Ｉｒ－３）を１００．３ｍｇ得た。得られた本発明化合物（Ｉｒ－３）はフェイシャル体であった。 Example 1-2 (Synthesis of the present compound (Ir-3))

75.5 mg of IrCl _{3.nH 2} 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 under heating 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.

^{The 1} H-NMR data of the compound of the present invention (Ir-3) is shown below.
^1H -NMR (400MHz/Acetone- _d6 ): 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).

酢酸イリジウム １０．０ｍｇ、配位子（Ｌ－２７）３５．１ｍｇ、ジエチレングリコール１ｍｌを三口フラスコに入れ、アルゴン雰囲気下、１５０℃で１５時間加熱反応させた。反応溶液を室温まで冷却後、析出した固体をメタノールで洗浄した。この固体をシリカゲルクロマトグラフィー（移動相：酢酸エチルとヘキサンの混合溶媒）で分離精製し、本発明化合物（Ｉｒ－２７）を３ｍｇ得た。得られた本発明化合物（Ｉｒ－２７）はフェイシャル体であった。 Example 1-3 (Synthesis of the present compound (Ir-27))

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 under argon atmosphere at 150° C. for 15 hours. 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.

^{The 1} H-NMR data of the compound of the present invention (Ir-27) is shown below.
¹ H-NMR (400 MHz/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).

酢酸イリジウム１０．０ｍｇ、配位子（Ｌ－２８）３５．１ｍｇ、ジエチレングリコール１ｍｌを三口フラスコに入れ、アルゴン雰囲気下、１５０℃で１５時間加熱反応させた。反応溶液を室温まで冷却後、析出した固体をメタノールで洗浄した。この固体をシリカゲルクロマトグラフィー（移動相：酢酸エチルとヘキサンの混合溶媒）で分離精製し、本発明化合物（Ｉｒ－２８）を４ｍｇ得た。得られた本発明化合物（Ｉｒ－２８）はフェイシャル体であった。 Example 1-4 (Synthesis of the present compound (Ir-28))

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 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 4 mg of the compound of the present invention (Ir-28). The compound of the present invention (Ir-28) obtained was a facial form.

^{The 1} H-NMR data of the compound of the present invention (Ir-28) is shown below.
¹ H-NMR (400 MHz/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).

塩化イリジウム三水和物５１．７ｍｇ、配位子（Ｌ－３５）１．４１ｇ、ジエチレングリコール３ｍｌをナスフラスコに入れ、窒素雰囲気下、５００Ｗのマイクロウェーブ（２４５０Ｈｚ）を３５分間照射した。反応溶液を室温まで冷却後、水を加え析出した固体をメタノールで洗浄した。この固体をシリカゲルクロマトグラフィー（移動相：ジクロロメタンとヘキサンの混合溶媒）で分離精製し、本発明化合物（Ｉｒ－３５）を３ｍｇ得た。得られた本発明化合物（Ｉｒ－３５）はフェイシャル体であった。 Example 1-5 (Synthesis of the present compound (Ir-35))

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.

^{The 1} H-NMR data of the compound of the present invention (Ir-35) is shown below.
^1H -NMR (400MHz/Acetone- _d6 ): 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).

ＩｒＣｌ_３・ｎＨ_２Ｏ １８０．３ｍｇ、配位子（Ｌ－３５）５０３．３ｍｇ、２－エトキシエタノール１０ｍｌナスフラスコに入れ、窒素雰囲気下、２４時間加熱還流させた。反応溶液を室温まで冷却後、水を加え中間体（Ｄ－３５）を含む沈殿を回収した。
引き続いて、中間体（Ｄ－３５）を含む沈殿６１４．５ｍｇ、アセチルアセトン７７．４ｍｇ、炭酸ナトリウム８１．１ｍｇ、２－エトキシエタノール１０ｍｌをナスフラスコに入れ、窒素雰囲気下、９０℃で４時間加熱反応させた。反応混合物を室温まで冷却後、水を加え析出した固体を回収した。得られた固体をシリカゲルクロマトグラフィー（移動相：トルエン）で分離精製し、本発明化合物（Ｉｒ－３８）を１４７ｍｇ得た。 Example 1-6 (Synthesis of the present compound (Ir-38))

180.3 _mg of _IrCl3.nH2O , 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 the 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 heating at 90°C for 4 hours under a nitrogen atmosphere. After the reaction mixture was cooled 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).

^{The 1} H-NMR data of the compound of the present invention (Ir-38) is shown below.
^1H -NMR (400MHz/Acetone- _d6 ): 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).

塩化イリジウム三水和物３３．５ｍｇ、配位子（Ｌ－７９）１５０ｍｇ、エチレングリコール３ｍｌをナスフラスコに入れ、窒素雰囲気下、２００℃で２時間加熱反応させた。反応溶液を室温まで冷却後、水を加え析出した固体をメタノールで洗浄した。この固体をシリカゲルクロマトグラフィー（移動相：ジクロロメタン）で分離精製し、本発明化合物（Ｉｒ－７９）を６ｍｇ得た。得られた本発明化合物（Ｉｒ－７９）はフェイシャル体であった。 Example 1-7 (Synthesis of the present compound (Ir-79))

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 by heating 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.

^{The 1} H-NMR data of the compound of the present invention (Ir-79) is shown below.
¹ H-NMR (400 MHz/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).

化合物（Ｄ－８８）２０２．７ｍｇ、トリフルオロメタンスルホン酸銀８０．５ｍｇ、ジクロロメタン１０ｍｌ、メタノール０．６ｍｌを三口フラスコに入れ、アルゴン雰囲気下、室温で６５時間撹拌した。反応溶液をセライト層に通してろ過し、得られたろ液を減圧濃縮して、中間体（Ｉ－８８）を得た。
引き続いて、上記で得られた中間体（Ｉ－８８）を全量、配位子（Ｌ－８８）３０１ｍｇ、エタノール６ｍｌをシュレンク管に入れ、アルゴン雰囲気下、９０℃で１８７時間加熱反応させた。室温まで冷却し析出した固体をろ過し、ジクロロメタンとヘキサンを用いて再結晶することで本発明化合物（Ｉｒ－８８）を得た。反応溶液については減圧留去し、これにエタノール３ｍｌを加え、アルゴン雰囲気下、２５日間加熱還流した。室温まで冷却し、析出した固体を吸引ろ過で回収した。これをシリカゲルカラムクロマトグラフィー（溶離液：ジクロロメタンと酢酸エチルの混合溶媒）で単離精製し、さらにジクロロメタンとヘキサンを用いて再結晶した。本発明化合物（Ｉｒ－８８）を合わせて２３６．６ｍｇ得た。 Example 1-8 (Synthesis of the present compound (Ir-88))

202.7 mg of compound (D-88), 80.5 mg of silver trifluoromethanesulfonate, 10 ml of dichloromethane, and 0.6 ml of methanol 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 obtained 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 thereto, 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 precipitated 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.

^{The 1} H-NMR data of the compound of the present invention (Ir-88) is shown below.
^1H -NMR (400MHz/Acetone- _d6 ): 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).

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) at room temperature was measured 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.

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) at room temperature was measured 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.

比較化合物（Ａ）をトルエンに溶解させ、アルゴンガスを通気した後、浜松ホトニクス株式会社製の絶対ＰＬ量子収率測定装置（Ｃ９９２０）を用いて、室温下での発光スペクトル（励起波長：３５０ｎｍ）を測定したところ、緑色発光（発光極大波長：５１０ｎｍ）を示した。発光スペクトルの半値幅（ＦＷＨＭ）は６６ｎｍであった。 Comparative Example 2-1 (Emission of Comparative Compound (A) in Toluene)

Comparative compound (A) 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 green light emission (maximum emission wavelength: 510 nm). The full width at half maximum (FWHM) was 66 nm.

比較化合物（Ｂ）をトルエンに溶解させ、アルゴンガスを通気した後、浜松ホトニクス株式会社製の絶対ＰＬ量子収率測定装置（Ｃ９９２０）を用いて、室温下での発光スペクトル（励起波長：３５０ｎｍ）を測定したところ、黄緑色発光（発光極大波長：５３１ｎｍ）を示した。発光スペクトルの半値幅（ＦＷＨＭ）は６３ｎｍであった。 Comparative Example 2-2 (Emission of Comparative Compound (B) in Toluene)

Comparative compound (B) 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. The emission spectrum showed yellow-green light emission (maximum emission wavelength: 531 nm). The full width at half maximum (FWHM) was 63 nm.

特開２０１１－１２１８７６に開示されている比較化合物（Ｃ）をトルエンに溶解させ、アルゴンガスを通気した後、浜松ホトニクス株式会社製の絶対ＰＬ量子収率測定装置（Ｃ９９２０）を用いて、室温下での発光スペクトル（励起波長：３５０ｎｍ）を測定したところ、青緑色発光（発光極大波長：４９２ｎｍ）を示した。発光スペクトルの半値幅（ＦＷＨＭ）は５４ｎｍであった。 Comparative Example 2-3 (Emission of Comparative Compound (C) in Toluene)

Comparative compound (C) disclosed in JP 2011-121876 A 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. The emission spectrum showed blue-green light emission (maximum emission wavelength: 492 nm). The full width at half maximum (FWHM) was 54 nm.

When comparing the emission characteristics of the compounds described in the Examples and Comparative Examples, it was found that the emission half width of the compounds of the present invention was 33 to 37 nm, while that of the comparative compounds was 54 to 66 nm, and therefore the compounds of the present invention exhibited superior emission characteristics with a narrower half width. Furthermore, when comparing the compounds of the present invention with the comparative compound (A), it was found that the emission wavelength was shifted to longer wavelengths 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 was changed, the emission wavelength was shifted to shorter wavelengths, and it was found that the opposite effect to that of the present invention was shown. Furthermore, when comparing the compounds of the present invention (Ir-27) and (Ir-28), it was found that (Ir-28) exhibited superior emission with a narrower emission half width, and therefore it was found that in the general formula (1), X ¹ is preferably C(R ⁶ ).

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) at room temperature was measured 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.

Example 2-4 (Emission of the compound of the present invention (Ir-3) in toluene)
The compound (Ir-3) of the present invention 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 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.

比較化合物（Ｄ）をトルエンに溶解させ、アルゴンガスを通気した後、浜松ホトニクス株式会社製の絶対ＰＬ量子収率測定装置（Ｃ９９２０）を用いて、室温下での発光スペクトル（励起波長：３５０ｎｍ）を測定したところ、青色発光（発光極大波長：４５６ｎｍ）を示した。発光スペクトルの半値幅（ＦＷＨＭ）は５１ｎｍであった。 Comparative Example 2-4 (Emission of Comparative Compound (D) in Toluene)

Comparative compound (D) 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. The emission spectrum showed blue light emission (maximum emission wavelength: 456 nm). The full width at half maximum (FWHM) was 51 nm.

Comparing the luminescence characteristics of the compounds described in Example 2-3, Example 2-4, and Comparative Example 2-4, it is clear 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 superior luminescence with a narrower half-width. Furthermore, comparing Examples 2-1 to 2-4, it is clear that the half-width is narrower when Ring A in General Formula (1) is a triazole ring than when it is a pyridine ring. In other words, it is clear that the effects of the present invention are particularly pronounced.

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) at room temperature was measured 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.

比較化合物（Ｅ）をトルエンに溶解させ、アルゴンガスを通気した後、浜松ホトニクス株式会社製の絶対ＰＬ量子収率測定装置（Ｃ９９２０）を用いて、室温下での発光スペクトル（励起波長：３５０ｎｍ）を測定したところ、全く発光を示さなかった。 Comparative Example 2-5 (Emission of Comparative Compound (E) in Toluene)

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.

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) at room temperature was measured 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).

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).

比較化合物（Ｆ）をトルエンに溶解させ、アルゴンガスを通気した後、浜松ホトニクス株式会社製の絶対ＰＬ量子収率測定装置（Ｃ９９２０）を用いて、室温下での発光スペクトル（励起波長：３５０ｎｍ）を測定したところ、橙色発光（発光極大波長：５８３ｎｍ）を示した。発光スペクトルの半値幅（ＦＷＨＭ）は９４ｎｍであった。発光のＣＩＥ色度座標は（ｘ，ｙ）＝（０．５７，０．４３）であった。 Comparative Example 2-6 (Emission of Comparative Compound (F) in Toluene)

The 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).

比較化合物（Ｇ）をトルエンに溶解させ、アルゴンガスを通気した後、浜松ホトニクス株式会社製の絶対ＰＬ量子収率測定装置（Ｃ９９２０）を用いて、室温下での発光スペクトル（励起波長：３５０ｎｍ）を測定したところ、赤色発光（発光極大波長：６０１ｎｍ）を示した。発光スペクトルの半値幅（ＦＷＨＭ）は７７ｎｍであった。発光のＣＩＥ色度座標は（ｘ，ｙ）＝（０．６３，０．３７）であった。 Comparative Example 2-7 (Emission of Comparative Compound (G) in Toluene)

The 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).

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 compound of the present invention has a narrower half-width of the luminescence than the comparative compound, 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 (11)

1. An iridium complex represented by the following general formula (1):

(In general formula (1), Ir represents an iridium atom, N represents a nitrogen atom, ring A represents a pyridine ring , a quinoline ring , a pyrazole ring , or a triazole ring, R ¹ , R ² and R ³ represent a hydrogen atom , X ¹ represents N or C(R ⁶ ), R ⁴ and R ⁵ each independently represent a branched alkyl group, R ⁶ represents a hydrogen atom , and L represents an anionic bidentate ligand. When a plurality of Ls 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. The iridium complex according to claim 1, wherein ring A is represented by the following general formula (2):

(In the general formula (2), N represents a nitrogen atom. ^X2 represents C ( ^R12 ) . ^X3 represents N. ^R7 to ^R11 each independently represent a hydrogen atom, an alkyl group, or an aryl group. ^R12 represents an alkyl group or an aryl group.) 2. The iridium complex according to claim 1, wherein ring A is represented by the following general formula (3):

(In formula (3), N represents a nitrogen atom. R ¹⁴ represents an alkyl group . R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, an alkyl group, or an aryl group.) 2. The iridium complex according to claim 1, wherein ring A is represented by the following general formula (4):

(In formula (4), N represents a nitrogen atom. R ¹⁷ to R ²² each independently represent a hydrogen atom, an alkyl group, or an aryl group.) 2. The iridium complex according to claim 1, wherein ring A is represented by the following general formula (5):

(In formula (5), N represents a nitrogen atom. R ²³ to R ²⁶ each independently represent a hydrogen atom, an alkyl group, or an aryl group.) 6. The iridium complex according to claim 1 , wherein X ¹ is C(R ⁶ ). 7. The iridium complex according to claim 1, wherein L is an aromatic heterocyclic bidentate ligand or a β-diketone ligand. 7. The iridium complex according to claim 1 , wherein m=3 and n=0. 8. The iridium complex according to claim 1 , wherein m=2 and n=1. A light-emitting material comprising the iridium complex according to any one of claims 1 to 9 . A light-emitting device comprising the light-emitting material according to claim 10 .

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