JP2005023070A - Metal coordination compound, polymer composition and organoelectroluminescent element obtained using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal coordination compound exhibiting blue phosphorescence of excellent color purity, a polymer composition, and an organoelectroluminescent element using the same. <P>SOLUTION: The metal coordination compound is represented by either one of formulae (1)-(6) (wherein M is Ir, Rh, Ru, Os, Pd or Pt; n is 2 or 3; when M is Ir, Rh, Ru or Os and n is 2, another bidentate ligand is bonded to M; the ring A is a cyclic compound containing a nitrogen atom bonded to M; X<SB>1</SB>-X<SB>7</SB>are each a hydrogen atom, a halogen atom, a cyano group, a nitro group, a straight chain, cyclic or branched alkyl or halogen-substituted alkyl group, an aryl group, a heteroaryl group, an aralkyl group, a halogen-substituted aryl group, a halogen-substituted heteroaryl group or a halogen-substituted aralkyl group; and the ring A may bear the same substituent group as the groups defined for X<SB>1</SB>-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

  However, when a full color organic EL device using phosphorescence emission is prepared, a metal coordination compound having blue phosphorescence emission with good color purity has not been found.

  In view of the above-described conventional problems, an object of the present invention is to provide a metal coordination compound having blue phosphorescence emission excellent in color purity. 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 having a carbazole derivative as a ligand is an excellent phosphorescent material having blue phosphorescence having excellent color purity, and completed the present invention. It came to do.

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 a hydrogen atom, a halogen atom, a cyano group, a nitro group, a carbon number of 1 to 22 straight-chain, cyclic or branched alkyl groups, or a halogen-substituted alkyl group in which a part or all of hydrogen atoms thereof are substituted with a halogen atom, an aryl group having 6 to 21 carbon atoms, or a group having 2 to 20 carbon atoms Any of a heteroaryl group, an aralkyl group having 7 to 21 carbon atoms, or a halogen-substituted aryl group, a halogen-substituted heteroaryl group or a halogen-substituted aralkyl group in which part or all of the hydrogen atoms are substituted with a halogen atom May also be, also, X ₁ to X ₇ may be the same or different and ring A may have the same substituent groups as defined in X ₁ to X ₇ .)

  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 shortening the wavelength of the emitted color.

  In the organic EL, in order to obtain blue phosphorescence, it is necessary that the energy level of the lowest excited state is high. However, in the conventional metal coordination compounds, the energy level in the lowest excited state was low for blue light emission, and thus the emission color was considered to have changed from blue-green to red.

Therefore, the present inventors have conducted various studies and found that the metal coordination compounds represented by the following formulas (1) to (6) have blue phosphorescence.

(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 a hydrogen atom, a halogen atom, a cyano group, a nitro group, a carbon number of 1 to 22 linear, cyclic or branched alkyl groups or halogen-substituted alkyl groups in which some or all of the hydrogen atoms are substituted with halogen atoms, aryl groups having 6 to 21 carbon atoms, heterocycles having 2 to 20 carbon atoms Any of an aryl group, an aralkyl group having 7 to 21 carbon atoms, or a halogen-substituted aryl group, a halogen-substituted heteroaryl group or a halogen-substituted aralkyl group in which part or all of the hydrogen atoms are substituted with a halogen atom May even, also, X ₁ to X ₇ may be the same or different and ring A may have the same substituent groups as defined in X ₁ to X _7. )

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 ₇ and R include a halogen atom such as a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a cyano group, a nitro group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclo Propyl, butyl, isobutyl, tert-butyl, cyclobutyl, pentyl, isopentyl, neopentyl, cyclopentyl, hexyl, cyclohexyl, heptyl, cycloheptyl, octyl, nonyl, decyl , Phenyl group, tolyl group, xylyl group, mesityl group, cumenyl group, benzyl group, phenethyl group, methylbenzyl group, diphenylmethyl group, 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, triazine residue, quinoline residue, quinoxaline residue or these are fluorine atom, chlorine atom, bromine atom, iodine atom, etc. And halogen-substituted products substituted with.

Among the metal coordination compounds represented by the formulas (1) to (6), the ring A is preferably any one of the cyclic compounds having the structure shown below, and X _{1 to} X ₇ (hereinafter collectively). Pyridine, quinoline, benzoxazole, benzothiazole, benzimidazole, benzotriazole, imidazole, pyrazole, oxazole, thiazole, triazole, which may have the same substituent as the group defined in (1). , Benzopyrazole or triazine is preferable, and pyridine or quinoline which may have the same substituent as the group defined by Xn is more preferable.

(Here, Z _{1 to} Z ₆ are a hydrogen atom, a halogen atom, a cyano group, a nitro group, a linear, cyclic or branched alkyl group having 1 to 22 carbon atoms, or a part or all of these hydrogen atoms are halogen atoms. A halogen-substituted alkyl group, an aryl group having 6 to 21 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, or a part or all of hydrogen atoms thereof is a halogen atom And may be any of a halogen-substituted aryl group, a halogen-substituted heteroaryl group, and a halogen-substituted aralkyl group substituted with, and Z _{1 to} Z ₆ may be the same or different.

  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.

Wherein Y ₁ to Y ₄ are a hydrogen atom, a halogen atom, a cyano group, a nitro group, a linear, cyclic or branched alkyl group having 1 to 22 carbon atoms, or a part or all of these hydrogen atoms are halogen atoms. A substituted halogen-substituted alkyl group, an aryl group having 6 to 21 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, or a part or all of hydrogen atoms thereof is a halogen atom. Any of a substituted halogen-substituted aryl group, a halogen-substituted heteroaryl group, and a halogen-substituted aralkyl group may be used, and Y _{1 to} Y ₄ may be the same or different.

In the metal coordination compounds represented by the formulas (1) to (6), at least one of the substituents Xn or the substituents defined in the same manner as Xn of the ring A is effective for shortening the emission wavelength. From the viewpoint of being, it is preferably a halogen atom, a cyano group or a halogen-substituted alkyl group, more preferably a fluorine atom, a chlorine atom, a cyano group or a trifluoromethyl group, and a fluorine atom or a trifluoromethyl group. More preferably, it is most preferably a fluorine atom. 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 or a halogen-substituted alkyl 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.

  In addition, the metal coordination compounds represented by the above formulas (1) to (6) are expected to have a high energy level in the lowest excited state, and are suitable as blue phosphorescent materials for organic EL.

(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 3-bromo-9-methylcarbazole (30 mmol) in a THF mixture of magnesium (1.9 g, 80 mmol) was stirred well under an argon stream. Slowly added 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 filtered with suction and washed with methanol to obtain a solid of 3- (2′-pyridyl) -9-methylcarbazole.

A 200 ml three-necked flask was charged with iridium (III) chloride (1.7 mmol), 3- (2′-pyridyl) -9-methylcarbazole (7.58 mmol), 50 ml of ethoxyethanol and 20 ml of water, and at room temperature under a nitrogen stream. For 30 minutes, 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. The mixture was dried under reduced pressure at room temperature to obtain a light yellow powder of di-μ-chloro-tetrakis [3- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ² ] diiridium (III).

In a 200 ml three-necked flask, 70 ml of ethoxyethanol, di-μ-chloro-tetrakis [3- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ² ] 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 [3- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ² ] (acetylacetonato ) A pale yellow powder of 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) 3- (2′-pyridyl) -9-methylcarbazole (1.7 mmol) and bis [3- (2 '-Pyridyl) -9-methylcarbazole-N ^1' , C ² ] (acetylacetonato) iridium (III) (0.28 mmol) and 55 ml of glycerol were added, and the mixture was heated and stirred at about 180 ° C. for 8 hours under a nitrogen stream. 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 to obtain a pale yellow powder of tris [3- (2′-pyridyl) -9-methylcarbazole-N ^{1 ′} , C ² ] iridium (III). It was.

Examples 3 to 9 Synthesis of various metal coordination compounds Except that the starting materials such as carbazole unit, ring A, and other ligands were changed, 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 10 Production of Organic EL Device Using the compound obtained in Example 2, an organic EL device having three organic layers was produced and the device 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 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 voltage was applied using ITO as a positive electrode and LiF / Al as a cathode, blue light emission (λ = 450 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.

Comparative Example 1
An organic EL device was produced in the same manner as in Example 10 except that Ir (ppy) ₃ was used instead of the metal coordination compound used in Example 10. 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 80 hours when the brightness | luminance half-life when driving by a fixed electric current (50mA / cm < ² >) was measured.

Claims (6)

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 a hydrogen atom, a halogen atom, a cyano group, a nitro group, a carbon number of 1 to 22 linear, cyclic or branched alkyl groups or halogen-substituted alkyl groups in which some or all of the hydrogen atoms are substituted with halogen atoms, aryl groups having 6 to 21 carbon atoms, heterocycles having 2 to 20 carbon atoms Any of an aryl group, an aralkyl group having 7 to 21 carbon atoms, or a halogen-substituted aryl group, a halogen-substituted heteroaryl group or a halogen-substituted aralkyl group in which part or all of the hydrogen atoms are substituted with a halogen atom May even, also, X ₁ to X ₇ may be the same or different and ring A may have the same substituent groups as defined in X ₁ to X _7. ) 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 or triazine. In the formulas (1) to (6), at least one of the substituents defined in the same manner as X _{1 to} X _{7 in the} ring A or X _{1 to} X ₇ of the ring A is a fluorine atom or a trifluoromethyl group. Item 3. The metal coordination compound according to Item 1 or 2.   The metal coordination compound according to claim 1, 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 1-4, or the polymer composition of Claim 5.