JP2005023071A - Metal coordination compound, polymer composition, and organic electroluminescent element using them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal coordination compound which emits light covering from green to red and has a long drive life, to provide a polymer composition, and to provide an organic electroluminescent element using them. <P>SOLUTION: The metal coordination compound is represented by any one of formulae (1) to (6) [wherein M is Ir, Rh, Ru, Os, Pd, or Pt; n is 2 or 3; another bidentate ligand is further bonded to M when M is Ir, Rh, Ru, or Os and n is 2; ring A is a cyclic compound containing a nitrogen atom bonded to M; X<SB>1</SB>to X<SB>7</SB>are each independently a substituent selected from the group consisting of -H, -OH, -R<SP>1</SP>, -OR<SP>2</SP>, -SR<SP>3</SP>, -OCOR<SP>4</SP>, -COOR<SP>5</SP>, -SiR<SP>6</SP>R<SP>7</SP>R<SP>8</SP>, -NH<SB>2</SB>, -NHR<SP>9</SP>, and -NR<SP>10</SP>R<SP>11</SP>(wherein R<SP>1</SP>to R<SP>11</SP>are each an alkyl group, an aryl group, a heteroaryl group, or an aralkyl group), provided that ring A may have a substituent similar to a group defined in X<SB>1</SB>to X<SB>7</SB>]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel metal coordination compound, a polymer composition, and an organic electroluminescence (EL) device using the same.

  In recent years, electroluminescent devices have attracted attention for use as large-area solid-state light sources as an alternative to incandescent lamps and gas-filled lamps, for example. On the other hand, it is also drawing attention as the most powerful self-luminous display that can replace liquid crystal displays in the field of flat panel displays (FPD). In particular, an organic electroluminescence (EL) element in which an element material is composed of an organic material has been commercialized as a low power consumption type full color FPD.

  Until now, a general organic EL element has taken out fluorescence when the excited singlet relaxes to the ground state. However, the proportion of excitons formed by injecting charges into the organic thin film is statistically said to be singlet: triplet = 1: 3, and the theoretical limit value of the internal quantum efficiency of the organic EL element is 25%. It is said. This has been an obstacle to reducing the power consumption of the organic EL element.

  As one means for solving this problem, an element utilizing phosphorescence from an excited triplet has been studied. If phosphorescence from an excited triplet can be used, a light emission quantum yield of at least three times in principle can be expected as compared with the case of using fluorescence from an excited singlet. Furthermore, considering the use of excitons by intersystem crossing from a singlet to a triplet in terms of energy, a luminescence quantum yield of 4 times, that is, 100% can be expected in principle.

  Examples of research so far include M.A.Baldo et al., Appl.Phys.Lett.1999.75.4. In this document, the following materials are used. Abbreviations for each material are as follows.

Alq ₃ : Aluminum-quinolinol complex (tris (8-quinolinolato) aluminum)
α-NPD: N, N'-Di-naphthalen-1-yl-N, N'-diphenyl-biphenyl-4,4'-diamine
CBP: 4,4'-N, N'-dicarbazole-biphenyl
BCP: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline
Ir (ppy) ₃ : iridium-phenylpyridine complex (tris (2-phenylpyridine) iridium)

Other examples utilizing light emission from excited triplets include JP-A-11-329739, JP-A-11-256148, and JP-A-8-319482.
MABaldo et al., Appl. Phys. Lett. 1999.75.4 JP 11-329739 A Japanese Patent Laid-Open No. 11-256148 JP-A-8-319482

  Development of phosphorescent metal coordination compounds with various emission colors and a long driving life when considering use in lighting applications as well as full-color organic EL devices using phosphorescence emission. desired. However, the driving life of phosphorescent light emitting devices has been shorter than that of fluorescent light emitting devices. The reason why the phosphorescent light emitting device has a short driving lifetime is not clear, but generally the lifetime of the excited triplet state is longer than the lifetime of the excited singlet, and the molecule stays in a high energy state for a long time. This is thought to be due to structural changes in the molecule itself, reactions between excitons, and so on.

  In view of the above-described conventional problems, an object of the present invention is to provide a metal coordination compound that emits light of various colors from green to red and has a long driving life. Another object of the present invention is to provide a polymer composition containing the metal coordination compound. Furthermore, an object of this invention is to provide the organic electroluminescent element using the said metal coordination compound or the said polymer composition.

  As a result of intensive studies, the present inventors have found that a metal coordination compound in which various substituents are introduced into a carbazole derivative as a ligand has an emission color ranging from green to red and has an excellent phosphorescence emission with a long driving life. As a result, the present invention was completed.

That is, the present invention relates to a metal coordination compound represented by any of the following formulas (1) to (6).

(Wherein M is Ir, Rh, Ru, Os, Pd or Pt and n is 2 or 3. When M is Ir, Rh, Ru or Os and n is 2, M is Further, other bidentate ligands are bonded.Ring A is a cyclic compound containing a nitrogen atom bonded to M. X _{1 to} X ₇ are each independently —H, —OH, —R ¹ , —OR ^2. , -SR ³ , -OCOR ⁴ , -COOR ⁵ , -SiR ⁶ R ⁷ R ⁸ , -NH ₂ , -NHR ⁹ , and -NR ¹⁰ R ¹¹ (wherein R ^{1 to} R ¹¹ have 1 to 22 carbon atoms) A linear, cyclic or branched alkyl group, an aryl group having 6 to 21 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, or an aralkyl group having 7 to 21 carbon atoms, wherein R ^{1 to} R ¹¹ are Each selected from the group consisting of the same or different) A substituent and, X ₁ to X ₇ may be the same or different and be ring A have the same substituent groups as defined in X ₁ to X ₇ Here, R ^{1 to} R ¹¹ may have a substituent, and examples of the substituent include a halogen atom, a cyano group, an aldehyde group, an amino group, an alkyl group, an alkoxy group, an alkylthio group, and a carboxyl group. Groups, sulfonic acid groups, nitro groups and the like. These substituents may be further substituted with a halogen atom, a methyl group or the like.

  The present invention also relates to a polymer composition obtained by mixing or copolymerizing the metal coordination compound with a conjugated or non-conjugated polymer.

  Moreover, this invention relates to the organic electroluminescent element produced using the said metal coordination compound or the said polymer composition.

  The metal coordination compound of the present invention is suitable, for example, as a material for an organic EL device having excellent light emission characteristics. These are particularly effective for extending the life of the device.

  In organic EL, in order to obtain phosphorescence emission from green to red, it is necessary to change the energy level of the lowest excited state. In general, the lifetime of the excited triplet state is longer than that of the excited singlet, and the molecule stays in a high energy state for a long time, causing reactions with surrounding substances, changes in the structure of the molecule itself, reactions between excitons, etc. For this reason, it is considered that the driving life of the phosphorescent light emitting device is short with the conventional metal coordination compounds.

Accordingly, the present inventors have made various studies, and the metal coordination compounds represented by the following formulas (1) to (6) have phosphorescence from green to red and have a long driving life. I found it to be a material.

(Wherein M is Ir, Rh, Ru, Os, Pd or Pt and n is 2 or 3. When M is Ir, Rh, Ru or Os and n is 2, M is Further, other bidentate ligands are bonded.Ring A is a cyclic compound containing a nitrogen atom bonded to M. X _{1 to} X ₇ are each independently —H, —OH, —R ¹ , —OR ^2. , -SR ³ , -OCOR ⁴ , -COOR ⁵ , -SiR ⁶ R ⁷ R ⁸ , -NH ₂ , -NHR ⁹ , and -NR ¹⁰ R ¹¹ (wherein R ^{1 to} R ¹¹ have 1 to 22 carbon atoms) A linear, cyclic or branched alkyl group, an aryl group having 6 to 21 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, or an aralkyl group having 7 to 21 carbon atoms, wherein R ^{1 to} R ¹¹ are Each selected from the group consisting of the same or different) A substituent and, X ₁ to X ₇ may be the same or different and be ring A have the same substituent groups as defined in X ₁ to X ₇ Here, R ^{1 to} R ¹¹ may have a substituent, and examples of the substituent include a halogen atom, a cyano group, an aldehyde group, an amino group, an alkyl group, an alkoxy group, an alkylthio group, and a carboxyl group. Groups, sulfonic acid groups, nitro groups and the like. These substituents may be further substituted with a halogen atom, a methyl group or the like.

Show examples of the substituent represented by X ₁ to X ₆ and R below, the invention is not limited to the following.

Examples of X _{1 to} X ₆ and R include a hydrogen atom, a hydroxyl group, an amino group, and the following substituents. Examples of -R ¹ include methyl group, ethyl group, propyl group, isopropyl group, cyclopropyl group, butyl group, isobutyl group, tert-butyl group, cyclobutyl group, pentyl group, isopentyl group, neopentyl group, cyclopentyl group, Hexyl, cyclohexyl, heptyl, cycloheptyl, octyl, nonyl, decyl, phenyl, tolyl, xylyl, mesityl, cumenyl, benzyl, phenethyl, methylbenzyl, diphenylmethyl , Styryl group, cinnamyl group, biphenyl residue, terphenyl residue, naphthyl group, anthryl group, fluorenyl group, furan residue, thiophene residue, pyrrole residue, oxazole residue, thiazole residue, imidazole residue, pyridine Residue, pyrimidine residue, pyrazine residue, tri Examples thereof include azine residues, quinoline residues, and quinoxaline residues. Examples of —OR ² include methoxy, ethoxy, propoxy, butoxy, tert-butoxy, octyloxy, tert-octyloxy, phenoxy, 4-tert-butylphenoxy, 1-naphthyloxy Group, 2-naphthyloxy group, and 9-anthryloxy group. Examples of —SR ³ include a methylthio group, an ethylthio group, a tert-butylthio group, a hexylthio group, an octylthio group, a phenylthio group, a 2-methylphenylthio group, and a 4-tert-butylphenylthio group. Examples of —OCOR ⁴ include an acetoxy group and a benzoyloxy group. Examples of —COOR ⁵ include methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group, phenoxycarbonyl group, naphthyloxycarbonyl group and the like. Examples of —SiR ⁶ R ⁷ R ⁸ include a trimethylsilyl group, a triethylsilyl group, a triphenylsilyl group, and the like. Examples of —NHR ⁹ include an N-methylamino group, an N-ethylamino group, an N-benzylamino group, and an N-phenylamino group. Examples of —NR ¹⁰ R ¹¹ include N, N-dimethylamino group, N, N-diethylamino group, N, N-diisopropylamino group, N, N-dibutylamino group, N, N-dibenzylamino group, N, N-diphenylamino group and the like can be mentioned.

Moreover, it is preferable that the ring A is any of the cyclic compounds having the structure shown below, and the same substitution as the group defined by X _{1 to} X ₇ (hereinafter collectively referred to as a substituent Xn). It is preferably a pyridine, quinoline, benzoxazole, benzothiazole, benzimidazole, benzotriazole, imidazole, pyrazole, oxazole, thiazole, triazole, benzopyrazole, triazine or isoquinoline, which may have a group, defined by Xn More preferred is pyridine, quinoline or isoquinoline which may have the same substituent as the above group.

(Here, Z _{1 to} Z ₆ are each independently —H, —OH, —R ¹ , —OR ² , —SR ³ , —OCOR ⁴ , —COOR ⁵ , —SiR ⁶ R ⁷ R ⁸ , —NH _2. , —NHR ⁹ , and —NR ¹⁰ R ¹¹ (wherein R ^{1 to} R ¹¹ are linear, cyclic or branched alkyl groups having 1 to 22 carbon atoms, aryl groups having 6 to 21 carbon atoms, carbon numbers 2 Represents a heteroaryl group having 20 to 20 carbon atoms or an aralkyl group having 7 to 21 carbon atoms, and R ^{1 to} R ¹¹ may be the same or different. Z _{1 to} Z ₆ may be the same or different.) Here, R ^{1 to} R ¹¹ may have a substituent, and examples of the substituent include a halogen atom, Cyano group, aldehyde group, amino group, alkyl group, alcohol Shi group, an alkylthio group, a carboxyl group, a sulfonic acid group, and a nitro group. These substituents may be further substituted with a halogen atom, a methyl group or the like.

  In the present invention, in formulas (1) to (6), M is preferably Ir.

In the case where the metal M is Ir, Rh, Ru, Os, and n = 2, the other ligand bonded to the metal M is preferably any one of the compounds having the following structure.

(Where Y ₁ to Y ₄ are each independently —H, —OH, —R ¹ , —OR ² , —SR ³ , —OCOR ⁴ , —COOR ⁵ , —SiR ⁶ R ⁷ R ⁸ , —NH ₂ , —NHR ⁹ and —NR ¹⁰ R ¹¹ (wherein R ^{1 to} R ¹¹ are linear, cyclic or branched alkyl groups having 1 to 22 carbon atoms, aryl groups having 6 to 21 carbon atoms, and 2 to 2 carbon atoms) 20 represents a heteroaryl group or an aralkyl group having 7 to 21 carbon atoms, and R ^{1 to} R ¹¹ may be the same or different from each other. Y _{1 to} Y ₄ may be the same or different.) Here, R ^{1 to} R ¹¹ may have a substituent, and examples of the substituent include a halogen atom, cyano Group, aldehyde group, amino group, alkyl group, alkoxy Group, an alkylthio group, a carboxyl group, a sulfonic acid group, and a nitro group. These substituents may be further substituted with a halogen atom, a methyl group or the like.

In the metal coordination compounds represented by the above formulas (1) to (6), at least one of the substituents defined in the same manner as the substituent Xn or Xn of the ring A has an emission color from green to red. From the viewpoint of easy control, it is preferably -R, -OR or -SR. When at least one of the substituents Xn or the substituents defined in the same manner as Xn of ring A has any of the above-mentioned substituents, the other Xn is often a hydrogen atom. It may be a substituent. For example, X ₇ is preferably an alkyl group, an aryl group, or a heteroaryl group.

  Of the metal coordination compounds represented by the formulas (1) to (6), the metal coordination compound represented by the formula (1) or (4) is preferable from the viewpoint of easy synthesis.

The metal coordination compound of the present invention has phosphorescence emission, and the lowest excited state is considered to be a triplet MLCT (Metal-to-Ligand charge transfer) excited state or a π-π ^* excited state. . Phosphorescent emission occurs when transitioning from these states to the ground state.

  The phosphorescent quantum yield of the luminescent material of the present invention was as high as 0.1 to 0.9, and the phosphorescence lifetime was 1 to 60 μs. The short phosphorescence lifetime is a condition for increasing the luminous efficiency when an organic EL device is used. That is, when the phosphorescence lifetime is long, the proportion of molecules in the excited triplet state increases, and the light emission efficiency decreases due to τ-τ anionization at a high current density. The metal coordination compound of the present invention is a material suitable for a light-emitting material of an organic EL device because it has high phosphorescence emission efficiency and a short emission lifetime.

  Further, the metal coordination compounds represented by the above formulas (1) to (6) change the energy level of the lowest excited state by changing the substituents variously, and as organic EL light emitting materials having green to red emission. Is suitable.

(Detailed description of the method for synthesizing metal coordination compounds)
Hereinafter, the method for synthesizing a metal coordination compound of the present invention will be described in detail using specific examples of the metal coordination compound.

  The metal coordination compound of the present invention can be produced by various synthetic methods known to those skilled in the art. For example, the method described in S. Lamansky et al., J. Am. Chem. Soc. 2001. 123. can be used. An example of the synthetic route of the metal coordination compound represented by the above formulas (1) to (6) used in the present invention (when ring A is a substituted pyridine) is shown by way of an iridium coordination compound. In addition, although what is demonstrated here is related to (2) shown in Table 1 below, other exemplary compounds can be synthesized by substantially the same method.

(Synthesis of ligand L)

(Synthesis of iridium complex)

Or

Illustrative compounds are shown below as specific examples of metal coordination compounds, but are not limited thereto. Note that X _{1 to} X ₄ in Table 1 represent a substituent of the ring A.

  The metal coordination compound of the present invention can be used as an active layer material for an electroluminescent device. The active layer means a layer that can emit light when an electric field is applied (light emitting layer), or a layer that improves charge injection or charge transfer (charge injection layer or charge transfer layer). Here, the charge means a negative or positive charge. The thickness of the active layer is preferably 10 to 100 nm, more preferably 20 to 60 nm, and still more preferably 20 to 40 nm.

  The metal coordination compound of the present invention may be used by mixing with other materials. Moreover, the electroluminescent element using the metal coordination compound of this invention may be laminated | stacked with the active layer containing the metal coordination compound of this invention in the layer containing materials other than said metal coordination compound. Materials that may be used in combination with the metal coordination compound of the present invention include known materials such as hole injection and / or hole transfer materials, electron injection and / or electron transfer materials, light-emitting materials, and binder polymers. Can be used. The material to be mixed may be a high molecular material or a low molecular material.

  Examples of usable materials for hole injection and / or hole transfer materials include arylamine derivatives, triphenylmethane derivatives, stilbene compounds, hydrazone compounds, carbazole compounds, high molecular weight arylamines, polyanilines, polythiophenes, etc. Examples are materials and materials obtained by polymerizing them. Usable materials for electron injection and / or electron transfer materials include oxadiazole derivatives, benzoxazole derivatives, benzoquinone derivatives, quinoline derivatives, quinoxaline derivatives, thiadiazole derivatives, benzodiazole derivatives, triazole derivatives, metal chelate complex compounds, And materials obtained by polymerizing them. Examples of the light-emitting material that can be used include arylamine derivatives, oxadiazole derivatives, perylene derivatives, quinacridone derivatives, pyrazoline derivatives, anthracene derivatives, rubrene derivatives, stilbene derivatives, coumarin derivatives, naphthalene derivatives, metal chelate complexes, Ir and Pt. Examples include materials such as metal complexes containing a central metal such as, and materials obtained by polymerizing them, polyfluorene derivatives, polyphenylene vinylene derivatives, polyphenylene derivatives, polythiophene derivatives, and the like. Any material that can be used for the binder polymer can be used as long as the properties are not significantly reduced. Examples of the binder polymer include materials such as polystyrene, polycarbonate, polyaryl ether, polyacrylate, polymethacrylate, and polysiloxane.

  Especially, in this invention, an organic electroluminescent element can be manufactured using said metal coordination compound and a low molecular material other than this as needed.

  Specific examples of the low molecular weight material include CBP (4,4′-N, N′-dicarbazole-biphenyl) and CDBP (2,2′-dimethyl-4,4′-N, N′-dicarbazole-biphenyl). And mCP (m-dicarbazole-benzene). The mixing ratio of the low molecular weight material and the metal coordination compound is 1 to 15% by weight of the metal coordination compound, more preferably 2 to 10% by weight, and further preferably 3 to 8% by weight based on the weight of the low molecular material. %. If the concentration of the metal coordination compound is too low, the light emission efficiency tends to decrease. If it is too high, concentration quenching occurs due to the interaction between the metal coordination compounds, and the light emission efficiency tends to decrease.

  Moreover, in this invention, an organic electroluminescent element can be manufactured using the polymer composition containing the said metal coordination compound and a conjugated and / or nonconjugated polymer. In the present invention, the polymer composition means a composition obtained by mixing the metal coordination compound with a conjugated and / or nonconjugated polymer, or a conjugated and / or nonconjugated polymer with the metal coordination compound. Refers to a composition obtained by copolymerization.

  Specific examples of the conjugated and / or non-conjugated polymers include polymers, units including polyfluorene, polyphenylene, poly (phenylene vinylene), polythiophene, polyquinoline, polyaniline, polyvinyl carbazole, etc. or their derivatives as the main skeleton. (That is, not only the structure in the main skeleton but also a side chain structure), benzene, naphthalene, anthracene, phenanthrene, chrysene, rubrene, pyrene, perylene, indene, azulene, adamantane, fluorene, fluorenone, dibenzofuran , Carbazole, dibenzothiophene, furan, pyrrole, pyrroline, pyrrolidine, thiophene, dioxolane, pyrazole, pyrazoline, pyrazolidine, imidazole, oxazole, thiazole, oxadiazo , Triazole, thiadiazole, pyran, pyridine, piperidine, dioxane, morpholine, pyridazine, pyrimidine, pyrazine, piperazine, triazine, trithiane, norbornene, benzofuran, indole, benzothiophene, benzimidazole, benzoxazole, benzothiazole, benzooxadiazole , Benzotriazole, purine, quinoline, isoquinoline, coumarin, sinoline, quinoxaline, acridine, phenanthroline, phenothiazine, flavone, triphenylamine, acetylacetone, dibenzoylmethane, picolinic acid, silole, porphyrin etc. or polymers containing the derivatives thereof Etc. The mixing or copolymerization ratio of these polymers and metal coordination compounds is preferably 0.1 to 20 parts by weight of the metal coordination compound with respect to 100 parts by weight of the polymer.

  As a solvent used in the polymer composition, chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene, mesitylene, anisole, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, ethyl cellosolve acetate, and the like can be used.

  In order to use the metal coordination compound or polymer composition of the present invention as an active layer material of an electroluminescent device, a method known to those skilled in the art, for example, vacuum deposition, inkjet, casting, dipping, printing or spinning. This can be achieved by laminating a thin film on the substrate using a coating or the like. Printing methods include letterpress printing, intaglio printing, offset printing, lithographic printing, letterpress reversal offset printing, screen printing, gravure printing, and the like. Such a laminating method can be carried out usually in a temperature range of -20 to + 300 ° C, preferably 10 to 100 ° C, particularly preferably 15 to 50 ° C. Moreover, drying of the laminated | stacked polymer solution can be normally implemented by normal temperature drying, heat drying by a hotplate, etc.

  An electroluminescent element usually includes an electroluminescent layer (light-emitting layer) between a cathode and an anode in which at least one of electrodes is transparent. Furthermore, one or more electron injection layers and / or electron transfer layers can be inserted between the electroluminescent layer (light emitting layer) and the cathode, and further one or more hole injection layers and / or A hole transport layer can be inserted between the electroluminescent layer (light emitting layer) and the anode. The cathode material is preferably a metal or metal alloy such as Li, Ca, Mg, Al, In, Cs, Mg / Ag, or LiF. As an anode material, a metal (eg, Au) or other material having metal conductivity, for example, an oxide (eg, ITO: indium oxide / tin oxide) on a transparent substrate (eg, glass or transparent polymer). It can also be used.

  The electron injection and / or electron transfer layer includes materials such as oxadiazole derivatives, benzoxazole derivatives, benzoquinone derivatives, quinoline derivatives, quinoxaline derivatives, thiadiazole derivatives, benzodiazole derivatives, triazole derivatives, metal chelate complex compounds, etc. Layer.

  For the hole injection and / or hole transfer layer, materials such as copper phthalocyanine, triphenylamine derivative, triphenylmethane derivative, stilbene compound, hydrazone compound, carbazole compound, high molecular weight arylamine, polyaniline, polythiophene, etc. The layer containing is mentioned.

  The present invention will be explained by the following examples, but the present invention is not limited to these examples. In addition to the examples shown below, when various metal coordination compounds of the present invention described above are used, it is possible to obtain an electroluminescent sensor element having excellent color purity, reliability, light emission characteristics, and the like. it can.

Example 1 Synthesis of Metal Coordination Compound (1) A THF solution of 2-hydroxy-6-bromo-9-methylcarbazole (30 mmol) in a THF mixture of magnesium (1.9 g, 80 mmol) under an argon stream It was gradually added while stirring well to prepare a Grignard reagent. The obtained Grignard reagent was gradually added dropwise to a THF solution of trimethyl borate ester (300 mmol) at −78 ° C. over 2 hours, followed by stirring for 2 days at room temperature. The reaction mixture was poured into 5% dilute sulfuric acid containing crushed ice and stirred. When the obtained aqueous solution was extracted with toluene and the extract was concentrated, a colorless solid was obtained. The obtained solid was recrystallized from toluene / acetone (1/2) to obtain a carbazole derivative boronic acid as colorless crystals (40%).

The obtained carbazole derivative boronic acid (12 mmol) and 1,2-ethanediol (30 mmol) were refluxed in toluene for 10 hours and then recrystallized from toluene / acetone (1/4). As a result, the carbazole derivative boron ester was colorless. Obtained as crystals.

To a toluene solution of 2-bromopyridine (10 mmol), a carbazole derivative boron ester (10 mmol), and Pd (0) (PPh ₃ ) ₄ (0.2 mmol), 2M K ₂ CO ₃ aqueous solution was added vigorously under an argon stream. The mixture was refluxed for 48 hours with stirring. The reaction mixture was cooled to room temperature and then poured into a large amount of methanol to precipitate a solid. The precipitated solid was subjected to suction filtration and washed with methanol to obtain 2-hydroxy-6- (2′-pyridyl) -9-methylcarbazole solid.

A 200 ml three-necked flask was charged with iridium (III) chloride (1.7 mmol), 2-hydroxy-6- (2′-pyridyl) -9-methylcarbazole (7.58 mmol), 50 ml ethoxyethanol and 20 ml water. The mixture was stirred at room temperature for 30 minutes under a nitrogen stream and then refluxed for 24 hours. The reaction product was cooled to room temperature, and the precipitate was collected by filtration, washed with water, and washed successively with ethanol and acetone. Drying under reduced pressure at room temperature gave a pale yellow powder of di-μ-chloro-tetrakis [2-hydroxy-6- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ⁷ ] diiridium (III). It was.

In a 200 ml three-necked flask, 70 ml of ethoxyethanol, di-μ-chloro-tetrakis [2-hydroxy-6- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ⁷ ] diiridium (III) ( 0.7 mmol), acetylacetone (2.10 mmol) and sodium carbonate (9.43 mmol) were added, and the mixture was stirred at room temperature under a nitrogen stream, and then stirred at reflux for 15 hours. The reaction product was ice-cooled, and the precipitate was collected by filtration and washed with water. The precipitate was purified by silica gel column chromatography (eluent: chloroform / methanol: 30/1) and bis [2-hydroxy-6- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ⁷ ]. A pale yellow powder of (acetylacetonato) iridium (III) was obtained.

In addition, about the obtained compound, the confirmation was performed by the NMR spectrum, IR spectrum, etc. The same applies to the compounds shown below.

Example 2 Synthesis of Metal Coordination Compound (2) In a 200 ml three-necked flask, 2-hydroxy-6- (2′-pyridyl) -9-methylcarbazole (1.7 mmol), the bis [ 2-Hydroxy-6- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ⁷ ] (acetylacetonato) iridium (III) (0.28 mmol) and 55 ml of glycerol were added and about 180 under nitrogen flow. The mixture was stirred at 8 ° C. for 8 hours. The reaction product was cooled to room temperature, poured into 350 ml of 1N hydrochloric acid, the precipitate was collected by filtration, washed with water, and dried under reduced pressure at 100 ° C. for 5 hours. The precipitate was purified by silica gel column chromatography using chloroform as an eluent, and tris [2-hydroxy-6- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ⁷ ] iridium (III) was diluted lightly. A yellow powder was obtained.

Examples 3 to 13 Synthesis of various metal coordination compounds Except for changing starting materials such as carbazole unit, ring A, and other ligands, the same method as the synthesis method of Example 1 and Example 2 was used. Various metal complex compounds as shown in Table 2 were synthesized.

Example 14 Production of Organic EL Element Using the compound obtained in Example 2, an organic EL element having three organic layers was produced, and the element characteristics were evaluated. On a glass substrate patterned with a width of 2 mm of ITO (indium tin oxide), α-NPD as a hole transport layer was formed in a thickness of 40 nm by a vacuum evaporation method using resistance heating in a vacuum chamber of 10 ⁻⁵ Pa. . On top of that, the metal coordination compound of the example was co-deposited with the CBP so that the weight ratio was 5% (film thickness 30 nm). Further, the Alq ₃ was deposited as a 30 nm thick electron transport layer. On top of this, 0.5 to 2 nm of LiF and 100 to 150 nm of Al were deposited as a cathode electrode layer.

  The characteristics of the organic EL element were measured at room temperature, the current-voltage characteristics were measured with a microammeter 4140B manufactured by Hewlett-Packard, and the luminance was measured with SR-3 manufactured by Topcon. When a voltage was applied using ITO as a positive electrode and LiF / Al as a cathode, orange light emission (λ = 590 nm) was observed at about 6V.

It was 200 hours when the luminance half-life time was measured when driving at a constant current (50 mA / cm ² ).

Comparative Example 1
An organic EL device was produced in the same manner as in Example 1 except that Ir (ppy) ₃ was used instead of the metal coordination compound used in Example 14. When the obtained device was connected to a power source and a voltage was applied using ITO as a positive electrode and LiF / Al as a cathode, green light emission (λ = 516 nm) was observed at about 6V.

It was 100 hours when the brightness | luminance half-life when driving by a fixed electric current (50mA / cm < ² >) was measured.

Claims (5)

A metal coordination compound represented by any one of formulas (1) to (6).

(Wherein M is Ir, Rh, Ru, Os, Pd or Pt and n is 2 or 3. When M is Ir, Rh, Ru or Os and n is 2, M is Further, other bidentate ligands are bonded.Ring A is a cyclic compound containing a nitrogen atom bonded to M. X _{1 to} X ₇ are each independently —H, —OH, —R ¹ , —OR ^2. , -SR ³ , -OCOR ⁴ , -COOR ⁵ , -SiR ⁶ R ⁷ R ⁸ , -NH ₂ , -NHR ⁹ , and -NR ¹⁰ R ¹¹ (wherein R ^{1 to} R ¹¹ have 1 to 22 carbon atoms) A linear, cyclic or branched alkyl group, an aryl group having 6 to 21 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, or an aralkyl group having 7 to 21 carbon atoms, wherein R ^{1 to} R ¹¹ are Each selected from the group consisting of the same or different) A substituent and, X ₁ to X ₇ may be the same or different and be ring A have the same substituent groups as defined in X ₁ to X ₇ Good.) In the above formulas (1) to (6), ring A may have the same substituent as the group defined by X _{1 to} X ₇ pyridine, quinoline, benzoxazole, benzothiazole, benzimidazole, The metal coordination compound according to claim 1, which is benzotriazole, imidazole, pyrazole, oxazole, thiazole, triazole, benzopyrazole, triazine or isoquinoline.   The metal coordination compound according to claim 1 or 2, wherein M in the formulas (1) to (6) is Ir.   A polymer composition comprising the metal coordination compound according to claim 1 and a conjugated and / or non-conjugated polymer.   The organic electroluminescent element produced using the metal coordination compound in any one of Claims 1-3, or the polymer composition of Claim 4.