WO2018084189A1 - Method for producing iridium complex, iridium complex, and light-emitting material comprising said compound - Google Patents

Abstract

Provided are: a novel method for producing a triscyclometalated iridium complex having three different aromatic heterocyclic ligands which is a complex that has been difficult to be synthesized so far; and a novel iridium complex which is produced by employing the production method, has high solubility in solvents and excellent processability, and can emit light at room temperature with high brightness and with high efficiency. A method for producing a triscyclometalated iridium complex having three aromatic heterocyclic ligands capable of forming an iridium-nitrogen bond and an iridium-carbon bond, wherein the structures of the aromatic heterocyclic ligands are different from one another, said method being characterized by comprising, in the following order, the steps of: (1) reacting a triscyclometalated iridium complex, which has two different aromatic heterocyclic ligands respectively capable of forming an iridium-nitrogen bond and an iridium-carbon bond, with a halogenating agent to introduce a halogen atom into the triscyclometalated iridium complex; (2) converting the halogen atom in the triscyclometalated iridium complex produced in step (1) to a boronic acid ester; and (3) subjecting the triscyclometalated iridium complex produced in step (2) and an organic halogen compound to a cross-coupling reaction to form a carbon-carbon bond.

Description

Method for producing iridium complex, iridium complex and light-emitting material comprising the compound

The present invention relates to a method for producing an iridium complex suitably used as a light-emitting material such as an organic electroluminescent element and a light-emitting sensor, a novel iridium complex obtained by the production method, and a light-emitting material comprising the compound.

In recent years, organic electroluminescent elements have been attracting attention as displays for televisions and mobile phones, and there is a strong demand for improved luminous efficiency for future practical use. Luminescent materials used for organic electroluminescent elements can be broadly classified into fluorescent materials that utilize light emission from an excited singlet state and phosphorescent materials that utilize light emission from an excited triplet state. In the case of using light emission from an excited singlet state, the generation ratio of singlet excitons to triplet excitons is 1: 3, and the generation probability of luminescent excitons is 25%. Further, since the light extraction efficiency is about 20%, the limit of the external extraction quantum efficiency is set to 5%. On the other hand, if the excited triplet state can also be used, the upper limit of the internal quantum efficiency is 100%, so that in principle the light emission efficiency is four times that in the case of using only the excited singlet state. Therefore, phosphorescent materials have been actively studied as light emitting materials for organic electroluminescent elements.

So far, cyclometalated iridium complexes are known as phosphorescent materials. In particular, the triscyclometalated iridium complex having three cyclometalated aromatic heterocyclic ligands has high thermal stability and excellent durability because it has three strong iridium-carbon bonds. Phosphorescent material.

As an example of such a triscyclometalated iridium complex, Patent Document 1 discloses an iridium complex in which all three cyclometalated aromatic heterocyclic ligands have the same structure (Chemical Formula 1). Patent Document 2 discloses an iridium complex having a different structure of a cyclometalated aromatic heterocyclic ligand by one (Chemical Formula 2). Non-Patent Document 1 discloses an iridium complex in which the structures of three cyclometalated aromatic heterocyclic ligands are all different (Chemical Formula 3).

International Publication No. 2000/070655 Pamphlet International Publication No. 2010/028151 Pamphlet

Up to now, it has been difficult to synthesize triscyclometalated iridium complexes having different aromatic heterocyclic ligand structures in a high yield using a conventionally known production method. For example, according to the knowledge of the present inventor, when tris (2,4-pentanedionato) iridium (III) and three different aromatic heterocyclic ligands are reacted simultaneously, various products are produced. For this reason, it is extremely difficult to isolate the desired iridium complex.

On the other hand, in Non-Patent Document 1, it is possible to produce a triscyclometalated iridium complex (Chemical Formula 3) having different aromatic heterocyclic ligand structures by a method comprising the following steps (A) to (E). It is disclosed.

Step (A): Reaction of iridium trichloride with two different aromatic heterocyclic ligands to obtain a chlorine-bridged iridium dimer mixture.

Step (B): The chlorine-bridged iridium dimer mixture obtained in step (A) is reacted with acetylacetone to obtain three types of iridium complex mixtures (B-1) to (B-3).

Step (C): The three types of iridium complex mixture obtained in step (B) are separated and purified by column chromatography to isolate the iridium complex (B-1).

Step (D): The iridium complex (B-1) obtained in step (C) is reacted with hydrochloric acid to obtain a chlorine-bridged iridium dimer.

Step (E): Reaction of the chlorine-bridged iridium dimer obtained in Step (D) with 2-phenylpyridine to form a desired tris-cyclometalated structure in which the structures of the cyclometalated aromatic heterocyclic ligands are all different. An iridium complex is obtained.

In the production method described in Non-Patent Document 1 described above, of the three types of iridium complexes (B-1) to (B-3) obtained in step (B), an aromatic heterocyclic ligand is used. It is necessary to isolate iridium complexes (B-1) having different structures. However, when the polarities of the three types of iridium complexes obtained in the step (B) are similar, it is extremely difficult to separate and purify the desired iridium complex. That is, the manufacturing method of the iridium complex described in Non-Patent Document 1 has an essential problem that can be applied only when the polarities of the three types of iridium complexes generated in the step (B) are greatly different. Furthermore, in the step (E), since the reaction is performed at a high temperature of 200 ° C., scrambling of the ligand is likely to occur, and it may be difficult to isolate a desired iridium complex.

Currently, in the field of organic electroluminescence devices, there is a strong demand for the development of phosphorescent materials with excellent luminescent properties. Until now, the molecular design guidelines for triscyclometalated iridium complexes have been cyclometalated as described above. The iridium complexes having the same aromatic heterocyclic ligand structure or the iridium complexes having only one different structure of the cyclometalated aromatic heterocyclic ligand were almost limited. If triscyclometalated iridium complexes with different aromatic heterocyclic ligand structures can be produced efficiently, the range of molecular design of phosphorescent materials will be greatly expanded, but this is extremely difficult to achieve. It was.

An object of the present invention is to provide a method for efficiently producing a triscyclometalated iridium complex having different aromatic heterocyclic ligand structures, which is preferably used in an organic electroluminescent device, a luminescent sensor, and the like. It is an object of the present invention to provide a novel iridium complex obtained by the production method and a luminescent material using the compound.

As a result of intensive studies in view of the above circumstances, the present inventors have found that triscyclometalated iridium complexes having different structures of aromatic heterocyclic ligands, which have been difficult to synthesize, are more efficient than conventional methods. We have developed a highly versatile manufacturing method that can be synthesized well. In fact, it has been demonstrated that various iridium complexes having a novel skeleton exhibiting excellent light emission characteristics can be produced using the production method of the present invention, and the present invention has been completed.

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

<1> A triscyclometalated iridium complex having three aromatic heterocyclic ligands that form an iridium-nitrogen bond and an iridium-carbon bond, all of which have different structures. A manufacturing method of
A triscyclometalated iridium complex having two different aromatic heterocyclic ligands forming an iridium-nitrogen bond and an iridium-carbon bond is reacted with a halogenating agent to form a halogen to the triscyclometalated iridium complex. Introducing an atom (1);
Converting the halogen atom of the triscyclometalated iridium complex produced in the step (1) to a boronate ester;
A step (3) of forming a carbon-carbon bond by performing a cross-coupling reaction between the triscyclometalated iridium complex produced in the step (2) and an organic halogen compound,
A method for producing a triscyclometalated iridium complex characterized by comprising sequentially.
<2> The method for producing an iridium complex according to 1 above, wherein the introduction of the halogen atom in the step (1) is performed in the para position counting from the carbon atom of the benzene ring bonded to iridium.
<3> The iridium complex according to 1 or 2 above, wherein the introduction of the halogen atom in the step (1) is performed by any one of two aromatic heterocyclic ligands having the same structure. Production method.
<4> In the triscyclometalated iridium complex used in the step (1), one or two para positions counted from the carbon atom of the benzene ring bonded to iridium are an alkyl group, an aryl group, or a heterocyclic group. 4. The method for producing an iridium complex according to any one of 1 to 3, wherein the iridium complex is substituted with any one of the above.
<5> The aromatic heterocyclic ligand is 2-phenylpyridine, 1-phenylisoquinoline, 2-phenylquinoline, 2-phenylimidazole, 5-phenyl-1,2,4-triazole, 3-phenyl- 1,2,4-triazole, 1-phenylpyrazole, 2-phenylpyrazine, 2-phenylpyrimidine, 4-phenylpyrimidine, 3-phenylpyridazine, benzo [h] quinoline, dibenzo [f, h] quinoxaline, 2,3 -Diphenylquinoxaline, imidazo [1,2-f] phenanthridine, and the ligand is at least one selected from the group consisting of an alkyl group, an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom 5. The iridium complex according to any one of 1 to 4 above, which may be substituted with one group Body manufacturing method.
<6> 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, ring B, and ring C each independently represent a 5-membered or 6-membered nitrogen-containing heterocycle. R ^a to R ^c each represent a group or an atom bonded to an atom contained in the ring structure of ring A to ring C, and R ^d to R ^f represent three carbons contained in the ring structure of each benzene ring. Each of R ^a to R ^f and R ¹ to R ³ bonded to an atom included in each ring structure independently represents a hydrogen atom, an alkyl group, or an aryl; Represents a group, a heterocyclic group, an alkylsilyl group, or a halogen atom, provided that at least one of R ¹ to R ³ is a substituent represented by any one of formulas (2) to (7). There, and a ^{R 1 ≠ R 2 ≠ R 3} . ^Moreover, our ^R a ~ R ^f Fine R ¹ groups each other adjacent the ^~ R ³ may be bonded to form a condensed ring.)

(In the general formulas (2) to (7), N represents a nitrogen atom. R ⁴ to R ²⁷ each independently represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom. And an adjacent group of R ⁴ to R ²⁷ may be bonded to each other to form a condensed ring.)
<7> The iridium complex as described in 6 above, which is represented by any one of the general formulas (8) to (15).

(In the general formulas (8) to (15), each of R ^a to R ^f bonded to an atom contained in each ring structure and R ² to R ³⁷ are each independently a hydrogen atom, an alkyl group, Represents an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom, R ^a to R ^f and R ² , adjacent groups of R ³ , and adjacent groups of R ⁴ to R ³⁷ May be bonded to each other to form a condensed ring, provided that the phenyl group having R ⁴ to R ⁸ , R ² , and R ³ are not the same group, and have R ⁴ to R ⁸ (The phenyl group, the phenyl group having R ²⁸ to R ³² , and the phenyl group having R ³³ to R ³⁷ are not the same group.)
<8> The ring A, ring B, and ring C are each independently a pyridine ring, a quinoline ring, an isoquinoline ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a quinoxaline ring, an imidazole ring, or a triazole ring. The iridium complex according to 6 or 7 above.
<9> The iridium complex according to any one of 6 to 8, wherein the ring A, the ring B, and the ring C are each independently a pyridine ring, a quinoline ring, or an isoquinoline ring.
<10> The iridium complex according to any one of 6 to 9, wherein R ^a to R ^f are a hydrogen atom, an alkyl group, or an aryl group.
<11> The iridium complex according to any one of 6 to 10, wherein any one of R ¹ to R ³ is a hydrogen atom.
<12> The iridium complex according to any one of 6 to 11, wherein R ^d to R ^f are all hydrogen atoms.
<13> A luminescent material comprising the iridium complex according to any one of 6 to 12 above.
<14> An organic light emitting device comprising the light emitting material as described in 13 above.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a new method for producing a triscyclometalated iridium complex which can be suitably used as a phosphorescent material such as an organic electroluminescent device and which has three different aromatic heterocyclic ligand structures. The A novel iridium complex having excellent light emission characteristics can be provided using the production method.

In addition, the novel iridium complex produced by the production method of the present invention is highly soluble in a solvent, excellent in processability, and exhibits strong light emission in the visible light region at room temperature. Can be suitably used. In addition, a light-emitting element using the compound exhibits high-luminance light emission in the visible light region, and thus is suitable for use in fields such as a display element, a display, a backlight, or an illumination light source.

2 is an emission spectrum of the compound (K-34) of the present invention in THF under an argon atmosphere.

Next, although an embodiment is shown and explained in detail about the present invention, the present invention is limited to these descriptions and is not interpreted. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

In the description of the general formula of the present invention, a hydrogen atom includes an isotope (such as a deuterium atom), and an atom constituting a substituent further includes the isotope.

First, symbols (Ir, N, ring A, ring B, ring C, R ^a to R ^f , R ¹ to R ³⁷ ) described in the general formulas (1) to (15) will be described below.

The same symbols described in the general formulas (1) to (15) are synonymous and the preferred ranges are also the same.

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

Ring A, Ring B, and Ring C each independently represent a 5-membered or 6-membered nitrogen-containing heterocyclic ring, and preferably a 6-membered nitrogen-containing heterocyclic ring. Ring A, ring B, and ring C may be the same or different, and are preferably the same. Here, the same means a nitrogen-containing heterocycle having the same skeleton, and does not consider substituents attached to the nitrogen-containing heterocycle.

Ring A, ring B and ring C are specifically pyridine ring, quinoline ring, isoquinoline ring, pyrimidine ring, pyrazine ring, pyridazine ring, quinoxaline ring, benzoquinoline ring, benzoquinoxaline ring, dibenzoquinoline ring, dibenzoquinoxaline Ring, phenanthridine ring, tetrazole ring, imidazole ring, or triazole ring are preferable, and pyridine ring, quinoline ring, isoquinoline ring, pyrimidine ring, pyrazine ring, pyridazine ring, quinoxaline ring, imidazole ring, or triazole ring are more preferable. A pyridine ring, a quinoline ring, an isoquinoline ring, an imidazole ring or a triazole ring is particularly preferable, a pyridine ring or an isoquinoline ring is further particularly preferable, and a pyridine ring is most preferable.

Ring A, Ring B, and Ring C may be substituted with at least one group selected from the group consisting of an alkyl group, an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom, and these substituents May be further substituted with the above substituents. As said substituent, an alkyl group, an aryl group, or a heterocyclic group is preferable, an alkyl group or an aryl group is more preferable, and an alkyl group is especially preferable.
That is, in the general formula (1), each of the ring A ~ ring C of R ^{a ~} each represent a bond to group or atom to atom contained in the ring structure R ^c, each independently, a hydrogen atom, an alkyl group, an aryl Represents a group, a heterocyclic group, an alkylsilyl group, or a halogen atom. Among these, R ^a to R ^c are preferably ^a hydrogen atom, an alkyl group, or an aryl group, and more preferably a hydrogen atom or an alkyl group. These substituents may be further substituted with at least one group selected from the group consisting of alkyl groups, aryl groups, heterocyclic groups, alkylsilyl groups, or halogen atoms.

In the general formula (1), each of R ^d to R ^f representing a group or atom bonded to three carbon atoms contained in the ring structure of each benzene ring is independently a hydrogen atom, an alkyl group Represents an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom. Among these, R ^d to R ^f are preferably a hydrogen atom, an alkyl group, or an aryl group, more preferably a hydrogen atom or an alkyl group, and particularly preferably all hydrogen atoms. These substituents may be further substituted with at least one group selected from the group consisting of alkyl groups, aryl groups, heterocyclic groups, alkylsilyl groups, or halogen atoms.

R ¹ to R ³ each independently represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom. However, at least one of R ¹ to R ³ is a substituent represented by any one of the general formulas (2) to (7). At least one of R ¹ to R ³ is preferably the general formulas (2) to (4) or (7), more preferably the general formulas (2) to (4), The formula (2) is particularly preferable.

However, R ¹ to R ³ are R ¹ ≠ R ² ≠ R ³ . R ¹ ≠ R ² ≠ R ³ means that R ¹ to R ³ are not the same group. For example, when R ¹ to R ³ are groups represented by the general formula (2), they are not the same group as long as any of R ⁴ to R ⁸ of the substituents is different.

Any ^{one of} R ¹ to R ³ is preferably a hydrogen atom or a halogen atom, and more preferably a hydrogen atom. In particular, R ³ is preferably a hydrogen atom.

Further, adjacent groups of R ^a to R ^f and R ¹ to R ³ may be bonded to each other to form a condensed ring.

R ⁴ to R ³⁷ each independently represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom, preferably a hydrogen atom, an alkyl group, or an aryl group. These substituents may be further substituted with at least one group selected from the group consisting of alkyl groups, aryl groups, heterocyclic groups, alkylsilyl groups, or halogen atoms. Further, adjacent groups of R ⁴ to R ³⁷ may be bonded to each other to form a condensed ring.

The alkyl group in the present specification does not include the carbon number of the substituent, and preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, 1 to 6 is more particularly preferable.

As the alkyl group in the present specification, a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl are preferable. Group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group Group, n-heptadecyl group, n-octadecyl group, neopentyl 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, particularly preferably a methyl group.

The aryl group in the present specification does not include the carbon number of the substituent, and preferably has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, 6 to 12 is more particularly preferable.

As the aryl group in the present specification, a phenyl group, a biphenyl-2-yl group, a biphenyl-3-yl group, a biphenyl-4-yl group, a p-terphenyl-4-yl group, or a p-terphenyl is preferable. -3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group , M-tolyl group, p-tolyl group, pt-butylphenyl group, p- (2-phenylpropyl) phenyl group, 4′-methylbiphenylyl group, 4 ″ -t-butyl-p-terphenyl- 4-yl, o-cumenyl, m-cumenyl, p-cumenyl, 2,3-xylyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 3, 4-xylyl group, 3,5-xylyl group, mesityl group m-quarterphenyl group, 1-naphthyl group or 2-naphthyl group, more preferably phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,3-xylyl group, 2 , 4-xylyl group, 2,5-xylyl group, 2,6-xylyl group, 3,4-xylyl group, 3,5-xylyl group or mesityl group, particularly preferably phenyl group or p-tolyl It is a group.

The heterocyclic group in the present specification does not include the carbon number of the substituent, preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, Numbers 1 to 6 are more particularly preferable.

As the heterocyclic group in the present specification, preferably an imidazolyl group, a pyridyl group, a pyrimidyl group, a triazyl group, a pyrazyl group, a pyridazyl group, a quinolyl group, a furyl group, a thienyl group, a dibenzothienyl group, a piperidyl group, a morpholino group, A benzoxazolyl group, a benzimidazolyl group, a benzthiazolyl group, a carbazolyl group, or an azepinyl group, more preferably a pyridyl group, a pyrimidyl group, a triazyl group, a pyrazyl group, a pyridazyl group, or a dibenzothienyl group, Particularly preferred is a pyridyl group, pyrimidyl group, triazyl group or dibenzothienyl group, and particularly preferred is a pyrimidyl group or dibenzothienyl group.

The alkylsilyl group in the present specification does not include the carbon number of the substituent, and preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, Numbers 1 to 6 are more particularly preferable.

The alkylsilyl group in the present specification is preferably a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, a dimethylphenyl group, a t-butyldimethylsilyl group, or a t-butyldiphenylsilyl group, and more preferably a trimethylsilyl group. An isopropylsilyl group, a t-butyldimethylsilyl group, and a t-butyldiphenylsilyl group.

The halogen atom in the present specification is preferably a chlorine atom, a bromine atom or an iodine atom, more preferably a bromine atom or an iodine atom, and particularly preferably a bromine atom.

Hereinafter, the method for producing the iridium complex according to the present invention will be described in more detail.

The method for producing an iridium complex according to the present invention is characterized by sequentially including steps (1) to (3) described in detail below.

In step (1), a triscyclometalated iridium complex having two different aromatic heterocyclic ligands that form an iridium-nitrogen bond and an iridium-carbon bond is reacted with a halogenating agent to form a triscyclometal. It is characterized by introducing a halogen atom into an iridium iodide complex.

Regarding the production method of the triscyclometalated iridium complex having two different aromatic heterocyclic ligands in the step (1), WO2012 / 166608, JP2011-68634, WO2013 / 098177, JP2016 -145216, JP 2016-121160, JP 2015-134823, JP 2013-147497, JP 2013-028604, WO 2013/137162, JP 2014-234360, etc. good.

The triscyclometalated iridium complex having two different aromatic heterocyclic ligands in the step (1) is preferably represented by the general formula (16) or (17). General formula (16) is a facial body, and general formula (17) is a meridional body. In the step (1), it is particularly preferable to use a facial body.

(In the general formulas (16) and (17), Y represents an aromatic heterocyclic ligand that forms an iridium-nitrogen bond and an iridium-carbon bond, and Z forms an iridium-nitrogen bond and an iridium-carbon bond. Represents an aromatic heterocyclic ligand, provided that Y ≠ Z.

In the step (1), examples of the aromatic heterocyclic ligand include 2-phenylpyridine, 1-phenylisoquinoline, 2-phenylquinoline, 2-phenylimidazole, 5-phenyl-1,2,4-triazole, 3 -Phenyl-1,2,4-triazole, 1-phenylpyrazole, 2-phenylpyrazine, 2-phenylpyrimidine, 4-phenylpyrimidine, 3-phenylpyridazine, benzo [h] quinoline, dibenzo [f, h] quinoxaline, 2,3-diphenylquinoxaline or imidazo [1,2-f] phenanthridine is preferred, and 2-phenylpyridine, 1-phenylisoquinoline, 2-phenylquinoline, 2-phenylimidazole, 5-phenyl-1,2 , 4-triazole, 3-phenyl-1,2,4-triazole Or, imidazo [1,2-f] phenanthridine more preferably, 2-phenylpyridine, 1-phenyl isoquinoline, or particularly preferably 2-phenyl quinoline, 2-phenylpyridine are most preferred. These aromatic heterocyclic ligands may be substituted with at least one group selected from the group consisting of an alkyl group, an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom. The group may be further substituted with the above substituents.

Introducing a halogen atom into the triscyclometalated iridium complex in the step (1) can be performed with reference to the methods described in WO2015 / 141603, WO2009 / 073245, JP2014-205643, and the like. A reaction example is shown below.

The introduction of the halogen atom in the step (1) is performed at the benzene ring part of the aromatic heterocyclic ligand forming the iridium-carbon bond, and the position is para-positioned from the carbon atom bonded to iridium. It is preferable that

The introduction of the halogen atom in the step (1) is preferably performed with two aromatic heterocyclic ligands having the same structure (Y in the general formula (16) or (17)). More preferably, the reaction is carried out in any one of two aromatic heterocyclic ligands (Y in the general formula (16) or (17)).

In the triscyclometalated iridium complex used in the step (1), the para-position (one or two, preferably one) counted from the carbon atom on the benzene ring bonded to iridium is an alkyl group, an aryl group, Alternatively, it is preferably substituted with a heterocyclic group, and more preferably substituted with an aryl group. Furthermore, the aromatic heterocyclic ligand substituted with the above substituent is an aromatic heterocyclic ligand (of the general formula (16) or (17), which is different from one of the triscyclometalated iridium complexes). More preferably, Z). As described above, when the para-position of the aromatic heterocyclic ligand Z is substituted with the substituent, the introduction site of the halogen atom in the iridium complex is represented by Y in the general formula (16) or (17). It was constrained by the para position, and it became clear that this facilitated purification of the produced iridium complex.

On the other hand, in the triscyclometalated iridium complex used in the step (1), the para position (one or two, preferably one) counted from the carbon atom on the benzene ring bonded to iridium is an alkyl group, aryl In the case where the group is not substituted with a group or a heterocyclic group, as shown below, there are a plurality of types of aromatic heterocyclic ligands to be halogenated, so that various iridium complexes can be obtained. Therefore, in the triscyclometalated iridium complex used in the step (1), the para-position (one or two, preferably one) counted from the carbon atom on the benzene ring bonded to iridium is an alkyl group, aryl Compared with the case where it is substituted with a group or a heterocyclic group, it takes more time to separate and purify the desired iridium complex in the step (2) or (3) described later.

As the halogenating agent used in the step (1), an iodinating agent, a brominating agent or a chlorinating agent is preferable, an iodinating agent or a brominating agent is more preferable, and a brominating agent is particularly preferable.

As the iodinating agent used in the step (1), for example, N-iodosuccinimide (NIS), 1,3-diiodo-5,5-dimethylhydantoin (DIH) and the like are preferably used.

As the brominating agent used in the step (1), for example, N-bromosuccinimide (NBS), dibromoisocyanuric acid (DBI), 1,3-dibromo-5,5-dimethylhydantoin and the like are preferably used.

As the chlorinating agent used in the step (1), for example, N-chlorosuccinimide (NCS), sodium dichloroisocyanurate and the like are preferably used.

The step (1) is characterized by using a triscyclometalated iridium complex having two different aromatic heterocyclic ligands that form an iridium-nitrogen bond and an iridium-carbon bond. When the metalated iridium complex is a facial body, a new geometric isomer is generated by the step (1), for example, as shown below. Thus, according to the production process (1) of the present invention, a new geometric isomerism can be obtained by reacting a triscyclometalated iridium complex having two different aromatic heterocyclic ligands with a halogenating agent. The body can be manufactured.

Step (2) is characterized in that the halogen atom of the triscyclometalated iridium complex produced in the step (1) is converted into a boronic ester.

The conversion from the halogen atom on the triscyclometalated iridium complex to the boronic acid ester in the step (2) is carried out with reference to the methods described in WO2015 / 141603, WO2009 / 073246, JP-A-2014-139193, etc. Can do. A typical reaction example is shown below.

In the step (2), when a triscyclometalated iridium complex into which a plurality of halogen atoms are introduced is used, an iridium complex into which a plurality of boronic acid esters are introduced may be generated. It is possible to separate and purify a triscyclometalated iridium complex into which one boronic acid ester has been introduced using silica gel column chromatography.

Step (3) is characterized in that the triscyclometalated iridium complex produced in Step (2) and an organic halogen compound are subjected to a cross-coupling reaction to form a carbon-carbon bond.

The method in which the triscyclometalated iridium complex and the halogen compound in the step (3) are cross-coupled is called a so-called Suzuki coupling reaction. For example, WO2015 / 141603, WO2009 / 073246, JP2014 -139193 can be used.

In the step (3), the organic halogen compound includes a halogenated aryl compound, a halogenated alkyl compound, a halogenated heterocyclic compound, etc., and the halogen is preferably iodine, bromine, or chlorine, iodine, or Bromine is more preferred.

The typical reaction example of the step (3) is shown below.

The iridium complex according to the present invention can be subjected to the post-treatment of a normal synthesis reaction, and then refined or used without further purification if necessary. The post-treatment can be performed, for example, by a method such as extraction, cooling, crystallization by adding water or an organic solvent, or an operation of distilling off the solvent from the reaction mixture. Purification can be performed by a single method or a combination of methods such as recrystallization, distillation, sublimation or column chromatography.

Hereinafter, the novel iridium complex obtained by the production method of the present invention will be described in detail.

The iridium complex obtained by the production method of the present invention is preferably represented by the general formula (1). Among them, the iridium complex represented by any one of the general formulas (8) to (15) is preferable, and the iridium complex represented by any one of the general formulas (8) to (10) and (13) to (15) Is more preferable, and an iridium complex represented by any one of the general formulas (9), (10), and (13) to (15) is particularly preferable.

Among the iridium complexes represented by the general formula (1) according to the present invention, those having an emission quantum yield in a solution at room temperature of 0.1 or more are preferable, and those having an emission quantum yield of 0.5 or more are more preferable. Preferably, it is 0.85 or more.

In order to remove dissolved oxygen, the measurement of the luminescence quantum yield in the solution is performed after passing argon gas or nitrogen gas through the solution in which the iridium complex is dissolved, or after freezing and degassing the solution in which the luminescent material is dissolved. Good to do. As a method for measuring the luminescence quantum yield, either an absolute method or a relative method may be used. In the relative method, the emission quantum yield can be measured by comparing the emission spectrum with a standard substance (such as quinine sulfate). In the absolute method, the emission quantum yield in the solution can be measured by using a commercially available apparatus (for example, an absolute PL quantum yield measuring apparatus (C9920-02) manufactured by Hamamatsu Photonics Co., Ltd.). Although the luminescence quantum yield in a solution can be measured using various solvents, the iridium complex according to the present invention only needs to achieve the luminescence quantum yield in any solvent.

Among the iridium complexes represented by the general formula (1) according to the present invention, the half width of the emission spectrum in a solution at room temperature is preferably 75.0 nm or less, and more preferably 72.5 nm or less. Those having a diameter of 70.0 nm or less are particularly preferable, and those having a diameter of 68.0 nm or less are particularly preferable. A narrow half-value width of the emission spectrum is particularly useful as a phosphorescent material for display applications.

The iridium complex represented by the general formula (1) according to the present invention is an octahedral 6-coordination complex, and there are a facial isomer and a meridional isomer as geometric isomers.

The iridium complex represented by the general formula (1) according to the present invention is preferably a facial body. The iridium complex according to the present invention preferably contains 50% or more of the facial compound, more preferably contains 80% or more, particularly preferably contains 90% or more, and contains 99% or more. It is more particularly preferable. The facial body or meridional body can be separated and purified using a technique 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 the general formula (1) according to the present invention or a solution containing the meridional isomer to isomerize to a facial isomer.

Since the iridium complex represented by the general formula (1) according to the present invention has three different aromatic heterocyclic ligands, it has further geometric isomers in addition to the facial and meridional isomers. In the production method of the present invention, as described above, two types of geometric isomers are generated in step (1), and in step (2) and step (3), the two types of geometric isomers are probably isomerized to each other. In the end, two geometric isomers are obtained. For example, the facial isomers of the present compound (K-40) shown below include geometric isomer 1 and geometric isomer 2. It was revealed that when the iridium complex represented by the general formula (1) according to the present invention was actually synthesized, it was obtained as a mixture of these geometric isomers (see Examples). The iridium complex of the present invention has practically excellent characteristics such as good solubility in a solvent and suppression of crystallization due to such structural characteristics.

In addition, homoleptic tris-cyclometalated iridium complexes with three identical cyclometalated ligands are highly symmetric and have good crystallinity in the solid state. There was a problem of lowering. On the other hand, since the iridium complex of the present invention represented by the general formula (1) has low symmetry, the crystallinity in the solid state is low, the energy for linking the complexes decreases, and the sublimation property tends to be improved.

As described above, the method for producing an iridium complex according to the present invention enables simple and efficient production of triscyclometalated iridium complexes having different structures of all three aromatic heterocyclic ligands. It is. Further, the iridium complex produced by the method of the present invention is excellent in the visible light region by being contained in a light emitting layer of a light emitting element or a plurality of organic compound layers including a light emitting layer by a vacuum deposition method, a spin coating method, or the like. A light-emitting element that emits light is obtained. Furthermore, by using the iridium complex of the present invention for a light-emitting element, a change in film quality (for example, crystallization of a material) is suppressed, and a light-emitting element having a stable and long life can be obtained.

A typical example of the iridium complex represented by the general formula (8) is shown in Chemical Formula 22.

A typical example of the iridium complex represented by the general formula (9) is shown in Chemical Formula 23.

A typical example of the iridium complex represented by the general formula (10) is shown in Chemical Formula 24.

A typical example of the iridium complex represented by the general formula (11) is shown in Chemical Formula 25.

A typical example of the iridium complex represented by the general formula (12) is shown in Chemical Formula 26.

A typical example of the iridium complex represented by the general formula (13) is shown in Chemical Formula 27.

A typical example of the iridium complex represented by the general formula (14) is shown in Chemical formula 28.

A typical example of the iridium complex represented by the general formula (15) is shown in Chemical formula 29.

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

Example 1 (Synthesis of Compound (K-40) of the Present Invention)

<Step 1 Synthesis of Compound A>

Compound (1) (2.0 g), silver trifluoromethanesulfonate (1.06 g), dichloromethane (110 ml) and methanol (2.5 ml) were stirred at 25 ° C. for 17 hours under an argon atmosphere. After completion of the reaction, the reaction solution was passed through a celite layer to remove insoluble matters. The filtrate was concentrated to dryness to obtain Compound (A) in a yield of 99%.

<Step 2 Synthesis of Compound B>

2.64 g of compound (A), 2.27 g of ligand (L-1), 60 ml of methanol, and 60 ml of ethanol were reacted by heating at 75 ° C. for 72 hours in an argon atmosphere. After completion of the reaction, the reaction solution was cooled to room temperature, and the precipitated solid was collected by filtration and washed with methanol. Further, the solid was separated and purified by silica gel chromatography (eluent: mixed solvent of ethyl acetate and hexane) to obtain Compound (B) in a yield of 40.9%. The ¹ H-NMR data of compound (B) are shown below. Compound (B) was a facial body.
¹ H-NMR (400 MHz / acetone-d ₆ ): δ (ppm) 8.28 (d, 1H), 8.09 (m, 3H), 7.79 (m, 5H), 7.69 (m, 3H), 7.56 (d, 2H), 7.20 (d, 2H), 7.09 (m, 4H), 6.92 (m, 5H), 6.84 (m, 2H), 2. 32 (s, 3H).

<Step 3 Synthesis of Compound C>

A mixture of 670 mg of compound (B) and 100 ml of dichloromethane was cooled to 0 ° C. in the dark. To this solution, 160 mg of N-bromosuccinimide was added and stirred at room temperature for 17 hours. After completion of the reaction, dichloromethane was distilled off under reduced pressure to obtain a solid. When this solid was analyzed by HPLC, it was revealed that the compound (B) and the compound (D) were contained in addition to the desired compound (C). The proportions were 12% for compound (B), 78% for compound (C), and 10% for compound (D). The mixture was used as it was in the next step 4 without further purification.

<Step 4 Synthesis of Compound E>

1.05 g of the compound (C) obtained in Step 3, 635 mg of bis (pinacolato) diboron, 1.1 g of potassium acetate, 50 ml of 1,4-dioxane, [1,1′-bis (diphenylphosphino) ferrocene] palladium ( II) 153 mg of dichloride dichloromethane adduct (Pd (dppf) ₂ Cl ₂ .CH ₂ Cl ₂ ) and 104 mg of 1,1′-bis (diphenylphosphino) ferrocene (dppf) were heated to reflux in an argon atmosphere for 17 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. The filtrate was concentrated under reduced pressure to obtain a solid. This was further separated and purified by silica gel chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 510 mg of the desired compound (E) consisting of a mixture of geometric isomers. The yield was 84%. ¹ H-NMR data and ESI-MS data of the compound (E) are shown below.
¹ H-NMR (400 MHz / acetone-d ₆ ): δ (ppm) 8.26 (dd, 1H), 8.08-8.13 (m, 3H), 8.03 (s, 1H), 7. 74-7.80 (m, 4H), 7.62-7.68 (m, 3H), 7.52-7.55 (m, 2H), 7.17 (d, 2H), 7.03- 7.10 (m, 5H), 6.80-6.98 (m, 4H), 6.73 (dd, 1H), 2.31 (s, 3H), 1.29 (s, 12H).
ESI-MS: m / z = 871.8 ([M + H] ⁺ )

<Step 5 Synthesis of Compound (K-40)>

Compound (E) 250 mg obtained in Step 4, SPhos (2-dicyclohexylphosphino-2 ', 6'-dimethoxybiphenyl) 24 mg, potassium phosphate 183 mg, 1-bromo-3,5-dimethylbenzene 160 mg, toluene 40 ml After argon gas was bubbled through the mixture of 4 ml of water for 30 minutes, 5.2 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was heated to reflux for 17 hours under an argon atmosphere. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was separated and purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 90 mg of the present compound (K-40) comprising a mixture of geometric isomers. The yield was 37%. ¹ H-NMR data and ESI-MS data of the compound of the present invention (K-40) are shown below.
¹ H-NMR (acetone-d ₆ , 400 MHz): δ 8.25-8.29 (m, 2H), 8.10 (d, 1H), 8.03-8.05 (m, 2H), 7. 62-7.81 (m, 7H), 7.53-7.56 (m, 2H), 7.26 (s, 2H), 7.18 (dd, 2H), 7.02-7.08 ( m, 5H), 6.91-6.97 (m, 4H), 6.83 (t, 1H), 6.73 (t, 1H), 2.30 (d, 9H).
ESI-MS: m / z = 850.8 ([M + H] ⁺ )

Example 2 (Synthesis of Compound (K-39) of the Present Invention)

Compound (E) 150 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 14 mg, potassium phosphate 110 mg, 1-bromo-4- (trifluoromethyl) benzene 116 mg, toluene 40 ml, water 4 ml After argon gas was bubbled through the mixture for 30 minutes, 3.1 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was heated to reflux for 17 hours under an argon atmosphere. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was separated and purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 30 mg of the present compound (K-39) comprising a mixture of geometric isomers. The yield was 20%. ¹ H-NMR data and ESI-MS data of the compound of the present invention (K-39) are shown below.
¹ H-NMR (acetone-d ₆ , 400 MHz): δ 8.34 (d, 1H), 8.29 (dd, 1H), 8.17 (t, 1H), 8.13 (d, 1H), 8 .05 (dd, 1H), 7.89 (dd, 2H), 7.68-7.85 (m, 10H), 7.53-7.56 (m, 2H), 7.01-7.20 (M, 7H), 6.84-6.94 (m, 3H), 6.72-6.76 (m, 1H), 2.31 (d, 3H).
ESI-MS: m / z = 889.8 ([M + H] ⁺ )

Example 3 (Synthesis of Compound (K-41) of the Present Invention)

Compound (E) 300 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 28 mg, potassium phosphate 220 mg, 5′-bromo-4,4 ″ -diisopropyl-1,1-3 ′, 1 After argon gas was bubbled through a mixture of 406.2 mg of -terphenyl, 50 ml of toluene and 5 ml of water for 30 minutes, 6.2 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was added under argon atmosphere for 17 hours. Heated to reflux. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was separated and purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 180 mg of the present compound (K-41) comprising a mixture of geometric isomers. The yield was 48.6%. The ¹ H-NMR data and ESI-MS data of the compound of the present invention (K-41) are shown below.
¹ H-NMR (acetone-d ₆ , 400 MHz): δ 8.37-8.40 (m, 1H), 8.25-8.31 (m, 2H), 8.10-8.13 (m, 1H ), 8.05-8.07 (m, 1H), 7.87-7.88 (m, 2H), 7.69-7.83 (m, 12H), 7.54-7.56 (m) , 2H), 7.34-7.37 (m, 4H), 7.17-7.24 (m, 3H), 6.92-7.12 (m, 7H), 6.83-6.86 (M, 1H), 6.73-6.77 (m, 1H), 2.93-3.00 (m, 2H), 2.31 (s, 3H), 1.28 (dd, 12H).
ESI-MS: m / z = 1057.9 ([M + H] ⁺ )

Example 4 (Synthesis of Compound (K-16) of the Present Invention)

To a mixture of Compound (E) 360 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 34 mg, potassium phosphate 263 mg, 5-bromo-2-tert-butylpyrimidine 267 mg, toluene 50 ml and water 5 ml After argon gas was bubbled for 30 minutes, 7.5 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was heated to reflux for 17 hours under an argon atmosphere. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 180 mg of the present compound (K-16) comprising a mixture of geometric isomers. The yield was 50.0%. The ¹ H-NMR data and ESI-MS data of the compound of the present invention (K-16) are shown below.
¹ H-NMR (acetone-d ₆ , 400 MHz): δ 8.98 (d, 2H), 8.39 (d, 1H), 8.29 (dd, 1H), 8.16-8.17 (m, 1H), 8.10-8.13 (m, 1H), 8.06-8.07 (m, 1H), 7.69-7.88 (m, 7H), 7.54-7.56 ( m, 2H), 7.02-7.20 (m, 8H), 6.85-6.94 (m, 3H), 6.72-6.77 (m, 1H), 2.31 (d, 3H), 1.39 (d, 9H).
ESI-MS: m / z = 880.3 ([M + H] ⁺ )

Example 5 (Synthesis of Compound (K-34) of the Present Invention)

Compound (E) 200 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 19 mg, potassium phosphate 146 mg, 4-bromodibenzothiophene 182 mg, toluene 40 ml, water 4 ml to a mixture of 30 argon gas After venting for minutes, 4.1 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was heated to reflux for 17 hours under an argon atmosphere. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 70 mg of the present compound (K-34) comprising a mixture of geometric isomers. The yield was 32.9%. The ¹ H-NMR data and ESI-MS data of the compound of the present invention (K-34) are shown below.
¹ H-NMR (acetone-d ₆ , 400 MHz): δ 8.19-8.33 (m, 5H), 8.10-8.15 (m, 1H), 8.06 (dd, 1H), 7. 91-7.95 (m, 1H), 7.74-7.85 (m, 6H), 7.70 (dd, 1H), 7.55-7.57 (m, 4H), 7.47- 7.50 (m, 2H), 6.95-7.20 (m, 10H), 6.84-6.87 (m, 1H), 6.75-6.80 (m, 1H), 2. 31 (s, 3H).
ESI-MS: m / z = 928.2 ([M + H] ⁺ )

Example 6 (Synthesis of Compound (K-10) of the Present Invention)

Compound (E) 150 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 14.1 mg, potassium phosphate 101 mg, 2-bromo-4,6-diphenylpyrimidine 161 mg, toluene 40 ml, water 4 ml After argon gas was bubbled through the mixture for 30 minutes, 3.1 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was heated to reflux for 17 hours under an argon atmosphere. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 11 mg of the present compound (K-10) comprising a mixture of geometric isomers. The yield was 5.9%. Present compound The ¹ H-NMR data and ESI-MS data (K-10) shown below.
¹ H-NMR (acetone-d ₆ , 400 MHz): δ 9.11 (dd, 1H), 8.46-8.49 (m, 4H), 8.28-8.32 (m, 3H), 8. 05-8.13 (m, 3H), 7.71-7.88 (m, 7H), 7.53-7.59 (m, 8H), 7.05-7.21 (m, 7H), 6.92-7.00 (m, 2H), 6.82-6.89 (m, 1H), 6.72-6.79 (m, 1H), 2.31 (d, 3H).
ESI-MS: m / z = 975.9 ([M + H] ⁺ )

Example 7 (Synthesis of Compound (K-46) of the present invention)

<Step 1 Synthesis of Compound (K-42)>

A mixture of 50 mg of compound (K-41) and 15 ml of dichloromethane was cooled to 0 ° C. To the reaction solution, 13.5 mg of N-bromosuccinimide was added under light shielding, and the mixture was stirred at 25 ° C. for 17 hours. After completion of the reaction, the reaction solution was distilled off under reduced pressure to obtain a solid. This solid was separated and purified by silica gel column chromatography (eluent: dichloromethane) to give the compound of the present invention (K-42) consisting of a mixture of geometric isomers.

<Step 2 Synthesis of Compound (K-46)>

Compound (K-42) 54 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 156 mg, tetraethylammonium hydroxide (20% aqueous solution) 245 mg, boronate ester compound (BE-1) 156 mg, THF 3 ml After argon gas was bubbled through the mixture for 30 minutes, 6 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was heated to reflux for 17 hours under an argon atmosphere. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was separated and purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 16 mg of the present compound (K-46) comprising a mixture of geometric isomers. The yield was 24.4%. The ¹ H-NMR data and ESI-MS data of the compound (K-46) are shown below.
¹ H-NMR (acetone-d ₆ , 400 MHz): δ 8.38-8.46 (m, 2H), 8.30-8.35 (m, 3H), 8.10 (s, 1H), 7. 90-7.92 (m, 4H), 7.79-7.82 (m, 2H), 7.74-7.77 (m, 14H), 7.57 (d, 2H), 7.52 ( d, 4H), 7.36 (d, 4H), 7.26-7.30 (m, 2H), 7.06-7.20 (m, 9H), 2.93-2.99 (m, 2H), 2.31 (s, 3H), 1.36 (s, 18H), 1.28 (d, 12H).
ESI-MS: m / z = 1398.6 ([M + H] ⁺ )

Example 8 (Synthesis of Compound (K-11) of the present invention)

Compound (E) 200 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 19 mg, potassium phosphate 146 mg, 2-bromo-4,6-di-tert-butylpyrimidine 156 mg, toluene 50 ml, water Argon gas was bubbled through 5 ml of the mixture for 30 minutes, then 4.2 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was heated to reflux for 17 hours under an argon atmosphere. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was purified by silica gel column chromatography (eluent: THF / hexane mixed solvent) to obtain 1 mg of the present compound (K-11) comprising a mixture of geometric isomers. The ESI-MS data of the compound of the present invention (K-11) are shown below.
ESI-MS: m / z = 936.3 ([M + H] ⁺ )

Example 9 (Synthesis of Compound (K-44) of the present invention)

<Step 1 Synthesis of Compound G>

A mixture of 300 mg of compound (F) and 150 ml of dichloromethane was cooled to 0 ° C. in the dark. To this solution, 57.5 mg of N-bromosuccinimide was added and allowed to stir at room temperature for 17 hours. After completion of the reaction, dichloromethane was distilled off under reduced pressure to obtain a solid. Analysis of this solid by HPLC revealed that the compound (F) was contained in addition to the desired compound (G). The proportion was 50% for compound (F) and 50% for compound (G). The mixture was used as it was in the next step 2 without further purification.

<Step 2 Synthesis of Compound H>

The total amount of the compound (G) obtained in Step 1 was 165 mg of bis (pinacolato) diboron, 286 mg of potassium acetate, 60 ml of 1,4-dioxane, [1,1′-bis (diphenylphosphino) ferrocene] palladium (II) Dichlorochloride adduct (Pd (dppf) ₂ Cl ₂ .CH ₂ Cl ₂ ) (49 mg) and 1,1′-bis (diphenylphosphino) ferrocene (dppf) (27 mg) were heated to reflux for 17 hours under an argon atmosphere. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. The filtrate was concentrated under reduced pressure to obtain a solid. This was further separated and purified by silica gel chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 60 mg of the desired compound (H) comprising a mixture of geometric isomers. The yield was 35%. The ESI-MS data of compound (H) is shown below.
ESI-MS: m / z = 1052.5 ([M + H] ⁺ )

<Step 3 Synthesis of Compound (K-44)>

Compound (H) 80 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 6.2 mg, potassium phosphate 42 mg, 5′-bromo-4,4 ″ -diisopropyl-1,1-3 ′ , 1 ″ -terphenyl 90 mg, toluene 20 ml, water 2 ml, argon gas was bubbled through for 30 minutes, then 1.4 mg of tris (dibenzylideneacetone) dipalladium (0) was added, and the mixture was added under argon atmosphere for 17 hours. Heated to reflux. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was separated and purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 60 mg of the present compound (K-44) comprising a mixture of geometric isomers. The yield was 64%. The ESI-MS data of the compound of the present invention (K-44) are shown below.
ESI-MS: m / z = 1238.6 ([M + H] ⁺ )

Example 10 (Synthesis of the present compound (K-43))

<Step 1 Synthesis of Compound J>

A mixture of 940 mg of compound (I) and 940 ml of dichloromethane was cooled to 0 ° C. in the dark. To this solution, 198 mg of N-bromosuccinimide was added and allowed to stir at room temperature for 17 hours. After completion of the reaction, dichloromethane was distilled off under reduced pressure to obtain a solid. When this solid was analyzed by HPLC, it was found that the compound (I) was contained in addition to the desired compound (J). The ratio was 13% of compound (I) and 87% of compound (J). The mixture was used as it was in the next step 2 without further purification.

<Step 2 Synthesis of Compound K>

The total amount of the compound (J) obtained in Step 1 was 565 mg of bis (pinacolato) diboron, 983 mg of potassium acetate, 150 ml of 1,4-dioxane, [1,1′-bis (diphenylphosphino) ferrocene] palladium (II) Dichlorochloride adduct (Pd (dppf) ₂ Cl ₂ .CH ₂ Cl ₂ ) 136 mg and 1,1′-bis (diphenylphosphino) ferrocene (dppf) 93 mg were heated to reflux for 17 hours under an argon atmosphere. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. The filtrate was concentrated under reduced pressure to obtain a solid. This was further separated and purified by silica gel chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 370 mg of the desired compound (K) consisting of a mixture of geometric isomers. The yield was 35%. The ESI-MS data of compound (K) is shown below.
ESI-MS: m / z = 972.1 ([M + H] ⁺ )

<Step 3 Synthesis of Compound (K-43)>

Compound (K) 370 mg, SPhos (2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl) 31.2 mg, potassium phosphate 66 mg, 5′-bromo-4,4 ″ -diisopropyl-1,1-3 ′ , 1 ″ -terphenyl 450 mg, toluene 100 ml, water 10 ml, argon gas was passed through for 30 minutes, tris (dibenzylideneacetone) dipalladium (0) 7 mg was added, and the mixture was heated to reflux for 17 hours under an argon atmosphere. did. Thereafter, the reaction solution was cooled to room temperature, and the reaction solution was filtered through a celite layer to remove insoluble matters. Dichloromethane was added to the filtrate for extraction, and the organic layer was concentrated under reduced pressure. The obtained solid was separated and purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane) to obtain 70 mg of the present compound (K-43) comprising a mixture of geometric isomers. The yield was 16%. ¹ H-NMR data and ESI-MS data of the compound of the present invention (K-43) are shown below.
¹ H-NMR (400 MHz / acetone-d ₆ ): δ (ppm) 9.13-9.17 (m, 1H), 8.99-9.03 (m, 1H), 8.63 (d, 1H ), 8.22-8.32 (m, 2H), 8.07 (d, 1H), 7.85-7.94 (m, 4H), 7.72-7.81 (m, 10H), 7.58-7.65 (m, 2H), 7.51-7.55 (m, 3H), 7.43-7.47 (m, 1H), 7.33-7.39 (m, 5H) ), 7.10-7.29 (m, 5H), 6.89-7.07 (m, 4H), 6.75-6.83 (m, 1H), 2.92-3.00 (m , 2H), 2.29-2.30 (m, 3H), 1.26-1.28 (m, 12H).
ESI-MS: m / z = 1158.2 ([M + H] ⁺ )

Comparative Example 1 Synthesis of Compound (K-40) Using Tris (acetylacetonato) iridium (III) 200 mg of Tris (acetylacetonato) iridium (III), 175 mg of ligand (L-1), coordination A child (L-2) (185 mg), 2-phenylpyridine (111 mg), and ethylene glycol (5 ml) were heated and reacted at 210 ° C. for 17 hours in an argon atmosphere. The reaction solution was cooled to room temperature, methanol was added, and the precipitated solid was collected by filtration. This solid was purified by silica gel column chromatography (eluent: mixed solvent of dichloromethane and hexane), but the compound (K-40) of the present invention could not be isolated from various products.

Comparative Example 2 Synthesis of Compound (K-40) by the Method described in Non-Patent Document 1 300 mg of iridium chloride trihydrate, 314 mg of ligand (L-1), 331 mg of ligand (L-2) Then, 6.3 ml of 2-ethoxyethanol and 2.1 ml of water were heated to reflux for 15 hours under an argon atmosphere. After cooling the reaction solution to room temperature, the precipitated solid was collected by filtration and washed with water and methanol. Further, this solid was recrystallized from dichloromethane and methanol to obtain 401 mg of a mixture of chlorine-bridged iridium dimers. Subsequently, 200 mg of the chlorine-bridged iridium dimer mixture, 167 mg of sodium acetylacetonate, 40 ml of 2-ethoxyethanol, and refluxed with heating in an argon atmosphere for 17 hours. After cooling to room temperature, the reaction solution was evaporated under reduced pressure, water was added thereto, and the precipitated solid was collected by filtration and washed with water and methanol. Furthermore, this solid was recrystallized with dichloromethane and methanol to obtain a yellow solid. The product obtained here contained compound (A-1), compound (A-2), compound (A-3) and the like. This mixture was separated and purified by column chromatography, but the compound (A-3) which is a precursor of the compound (K-40) of the present invention could not be isolated. Therefore, the compound (K-40) of the present invention could not be obtained.

As described above, triscyclometalated iridium complexes having different structures of the three aromatic heterocyclic ligands, which were extremely difficult to synthesize by the conventional method, can be easily and widely produced by the production method of the present invention. It became possible to synthesize. By the production method of the present invention, it is possible to greatly increase the variations of the triscyclometalated iridium complex that can be applied to organic electroluminescent elements and the like, and contribute to the development and practical application of phosphorescent materials.

Next, the light emission characteristics of the novel skeleton triscyclometalated iridium complex synthesized by the production method of the present invention will be described.

Example 11 (Luminescence of the compound (K-40) of the present invention in THF)
The compound (K-40) of the present invention was dissolved in THF and aerated with argon gas, and then the emission spectrum (excitation wavelength) at room temperature was measured using an absolute PL quantum yield measuring device (C9920) manufactured by Hamamatsu Photonics Co., Ltd. : 350 nm), green light emission (emission maximum wavelength: 520.0 nm) was observed. The emission quantum yield was 0.89. The half width of the emission spectrum was 71.9 nm.

Example 12 (Emission of Compound (K-41) of the present invention in THF)
The compound (K-41) of the present invention was dissolved in THF and aerated with argon gas, and then the emission spectrum (excitation wavelength) at room temperature was measured using an absolute PL quantum yield measuring device (C9920) manufactured by Hamamatsu Photonics Co., Ltd. : 350 nm), green light emission (emission maximum wavelength: 519.3 nm) was observed. The emission quantum yield was 0.88. The half width of the emission spectrum was 67.8 nm.

Example 13 (Luminescence of the compound (K-16) of the present invention in THF)
The compound (K-16) of the present invention was dissolved in THF and argon gas was passed through, and then the emission spectrum (excitation wavelength) at room temperature was measured using an absolute PL quantum yield measuring device (C9920) manufactured by Hamamatsu Photonics Co., Ltd. : 350 nm), green light emission (emission maximum wavelength: 518.5 nm) was exhibited. The emission quantum yield was 0.89. The half width of the emission spectrum was 69.3 nm.

Example 14 (Emission of compound of the present invention (K-34) in THF)
The compound (K-34) of the present invention was dissolved in THF and aerated with argon gas, and then the emission spectrum (excitation wavelength) at room temperature was measured using an absolute PL quantum yield measuring device (C9920) manufactured by Hamamatsu Photonics Co., Ltd. : 350 nm), green light emission (emission maximum wavelength: 519.3 nm) was observed. The emission quantum yield was 0.88. The half width of the emission spectrum was 68.0 nm.

Example 15 (Emission of Compound (K-10) of the present invention in THF)
The compound (K-10) of the present invention was dissolved in THF and aerated with argon gas, and then the emission spectrum (excitation wavelength) at room temperature was measured using an absolute PL quantum yield measuring device (C9920) manufactured by Hamamatsu Photonics Co., Ltd. : 350 nm), green light emission (emission maximum wavelength: 515.6 nm) was exhibited. The emission quantum yield was 0.87. The half width of the emission spectrum was 66.8 nm.

Example 16 (luminescence of the present compound (K-46) in THF)
The compound (K-46) of the present invention was dissolved in THF and aerated with argon gas, and then the emission spectrum (excitation wavelength) at room temperature was measured using an absolute PL quantum yield measuring device (C9920) manufactured by Hamamatsu Photonics Co., Ltd. : 350 nm), green light emission (emission maximum wavelength: 520.8 nm) was observed. The emission quantum yield was 0.88. The half width of the emission spectrum was 70.7 nm.

Comparative Example 3 (Luminescence of Ir (ppy) ₃ in THF)
Ir (ppy) ₃ (the iridium complex of [Chemical Formula 1]) was dissolved in THF and aerated with argon gas, and then at room temperature using an absolute PL quantum yield measuring device (C9920) manufactured by Hamamatsu Photonics Co., Ltd. When the emission spectrum (excitation wavelength: 350 nm) of was measured, it showed green emission (emission maximum wavelength: 514.8 nm). The emission quantum yield was 0.84. The half width of the emission spectrum was 72.7 nm.

Next, the solubility of the novel skeleton triscyclometalated iridium complex synthesized by the production method of the present invention in a solvent will be described.

Example 17 (Solubility of the compound of the present invention)
Solvents of (K-40), (K-39), (K-41), (K-16), (K-34), and (K-10) synthesized in Examples 1 to 6 (chloroform, In order to confirm the solubility in toluene, 0.1 wt% solutions were prepared and visually confirmed, and it was found that they were completely dissolved.

Comparative Example 4 (Solubility of Comparative Compound)
In order to confirm the solubility of Ir (ppy) _{3 in} a solvent (chloroform, toluene), a 0.1 wt% solution was prepared and visually confirmed.

Comparative Example 5 (Solubility of Comparative Compound)
In order to confirm the solubility of the compound (B) synthesized in Step 2 of Example 1 in the solvent (chloroform, toluene), a 0.1 wt% solution was prepared and visually confirmed. occured.

From Examples 11 to 16 and Comparative Example 3, the iridium complex represented by the general formula (1) of the present invention showed a higher emission quantum yield than Ir (ppy) ₃ . Furthermore, it was revealed that the half width of the emission spectrum of the iridium complex represented by the general formula (1) of the present invention is narrower than Ir (ppy) ₃ . The iridium complex represented by the general formula (1) of the present invention is a novel compound synthesized for the first time by the production method of the present invention, and has a light emission spectrum having a sharper shape with higher luminous efficiency than Ir (ppy) _3. As shown, it is particularly useful as a phosphorescent material for display applications.

Furthermore, from Example 17 and Comparative Examples 4 and 5, the iridium complex of the present invention, in which the structures of the three aromatic heterocyclic ligands are all different, is an iridium complex in which all of the aromatic heterocyclic ligands have the same structure ( It can be seen that the solubility in the solvent is superior to Ir (ppy) ₃ ) and the iridium complex (compound (B)) in which only one aromatic heterocyclic ligand structure is different. The iridium complex of the present invention described in Example 17 was synthesized by introducing a substituent into the compound (B), and the structures of the three aromatic heterocyclic ligands were all different from each other. It was revealed that it showed high solubility in the solvent.

Claims (14)

1. Method for producing triscyclometalated iridium complex having three aromatic heterocyclic ligands forming iridium-nitrogen bond and iridium-carbon bond, and different structures of the aromatic heterocyclic ligands Because
   A triscyclometalated iridium complex having two different aromatic heterocyclic ligands forming an iridium-nitrogen bond and an iridium-carbon bond is reacted with a halogenating agent to form a halogen to the triscyclometalated iridium complex. Introducing an atom (1);
   Converting the halogen atom of the triscyclometalated iridium complex produced in the step (1) to a boronate ester;
   A step (3) of forming a carbon-carbon bond by performing a cross-coupling reaction between the triscyclometalated iridium complex produced in the step (2) and an organic halogen compound,
   A method for producing a triscyclometalated iridium complex characterized by comprising sequentially.
2. The method for producing an iridium complex according to claim 1, wherein the introduction of the halogen atom in the step (1) is performed at the para position counting from the carbon atom of the benzene ring bonded to iridium.
3. The method for producing an iridium complex according to claim 1 or 2, wherein the introduction of the halogen atom in the step (1) is performed by any one of two aromatic heterocyclic ligands having the same structure. .
4. In the triscyclometalated iridium complex used in the step (1), one or two of the para positions counted from the carbon atom of the benzene ring bonded to iridium is an alkyl group, an aryl group, or a heterocyclic group. The method for producing an iridium complex according to any one of claims 1 to 3, wherein the iridium complex is substituted with.
5. The aromatic heterocyclic ligand is 2-phenylpyridine, 1-phenylisoquinoline, 2-phenylquinoline, 2-phenylimidazole, 5-phenyl-1,2,4-triazole, 3-phenyl-1,2, 4-triazole, 1-phenylpyrazole, 2-phenylpyrazine, 2-phenylpyrimidine, 4-phenylpyrimidine, 3-phenylpyridazine, benzo [h] quinoline, dibenzo [f, h] quinoxaline, 2,3-diphenylquinoxaline, The ligand is selected from imidazo [1,2-f] phenanthridine, and the ligand is substituted with at least one group selected from the group consisting of an alkyl group, an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom The iridium complex according to any one of claims 1 to 4, which may be Production method.
6. 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, ring B, and ring C each independently represent a 5-membered or 6-membered nitrogen-containing heterocycle. R ^a to R ^c each represent a group or an atom bonded to an atom included in the ring structure of ring A to ring C, and R ^d to R ^f represent three carbon atoms included in the ring structure of each benzene ring. Each of R ^a to R ^f and R ¹ to R ³ bonded to an atom included in each ring structure independently represents a hydrogen atom, an alkyl group, an aryl group, Represents a heterocyclic group, an alkylsilyl group, or a halogen atom, provided that at least one of R ¹ to R ³ is a substituent represented by any one of the general formulas (2) to (7); and a ^{R 1 ≠ R 2 ≠ R 3} . also, adjacent ^R a ~ R And, R 1 ^~ R ³ may form a condensed ring each coupled to.)
   

   

   (In the general formulas (2) to (7), N represents a nitrogen atom. R ⁴ to R ²⁷ each independently represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom. (In addition, adjacent R ⁴ to R ²⁷ may be bonded to each other to form a condensed ring.)
7. The iridium complex according to claim 6, which is represented by any one of the general formulas (8) to (15).
   

   

   

   

   

   (In the general formulas (8) to (15), each of R ^a to R ^f bonded to an atom contained in each ring structure and R ² to R ³⁷ are each independently a hydrogen atom, an alkyl group, R represents an aryl group, a heterocyclic group, an alkylsilyl group, or a halogen atom, and adjacent R ^a to R ^f and R ² to R ³⁷ may be bonded to each other to form a condensed ring. However, the phenyl group having R ⁴ to R ⁸ , R ² , and R ³ are not the same group, the phenyl group having R ⁴ to R ⁸ , the phenyl group having R ²⁸ to R ³² , and (The phenyl groups having R ³³ to R ³⁷ are not the same group.)
8. Ring A, ring B, and ring C are each independently a pyridine ring, quinoline ring, isoquinoline ring, pyrimidine ring, pyrazine ring, pyridazine ring, quinoxaline ring, imidazole ring, or triazole ring. Item 8. The iridium complex according to Item 6 or 7.
9. The iridium complex according to any one of claims 6 to 8, wherein each of the ring A, the ring B, and the ring C is independently a pyridine ring, a quinoline ring, or an isoquinoline ring.
10. 10. The iridium complex according to claim 6, wherein R ^a to R ^f are a hydrogen atom, an alkyl group, or an aryl group.
11. The iridium complex according to any one of claims 6 to 10, wherein any one of R ¹ to R ³ is a hydrogen atom.
12. 12. The iridium complex according to claim 6, wherein R ^d to R ^f are all hydrogen atoms.
13. A luminescent material comprising the iridium complex according to any one of claims 6 to 12.
14. An organic light emitting device comprising the light emitting material according to claim 13.

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