JP2010083852A - Method for producing metal complex, metal complex and organic electroluminescent device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a metal complex easily at a high yield compared with conventional methods. <P>SOLUTION: The metal complex having a desired ligand can be produced simply by dissolving a compound having a partial structure expressed by formula (1) and a desired ligand compound in a proper solvent and reacting the compounds. In the formula, M is a metal element selected from metals of the fourth to seventh period of the periodic table; and X<SP>11</SP>to X<SP>26</SP>are each independently a hydrogen atom or a substituent, provided that at least one of X<SP>11</SP>to X<SP>26</SP>is a halogen atom. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a metal complex useful for an organic electroluminescence device or the like. The present invention also relates to a metal complex produced by this method and an organic electroluminescent device using the metal complex.

  Conventionally, a lot of fluorescent materials have been used for organic electroluminescent devices, but it is necessary to further improve the luminous efficiency of the devices in order to apply to displays such as flat panel displays and lighting such as fluorescent lamps and marker lamps. There is a need to develop new light-emitting materials.

  In recent years, as one of attempts to increase the light emission efficiency of an element, use of a phosphorescent material using light emission from a triplet excited state, that is, phosphorescence, has attracted attention. This is because, when phosphorescence is used, it is possible to obtain a very high light extraction efficiency as compared with conventional light emission (fluorescence) from a singlet excited state, and high emission efficiency of the element is expected. .

  For example, in Non-Patent Document 1, by doping 4,4′-di (N-carbazolyl) biphenyl (CBP) with a phenylpyridine-based organic iridium complex, green emission with an emission wavelength of 510 nm is exhibited, and the external quantum efficiency is It is reported that the quantum efficiency limit value (5%) of the conventional singlet light emitting device is 13%, which is much higher.

  However, in particular, phosphorescent materials such as these metal complexes have not yet been fully developed, and have not been put into practical use because the degree of design freedom is low. For example, Patent Document 1 describes a method for synthesizing a platinum complex, but it is still not satisfactory.

  Non-Patent Document 2 describes the following synthesis method as a method of platinum bisphenylpyridyl complex.

In this method, bromination of ortho-position of 2-phenylpyridine, which is a starting material, followed by lithiation, followed by reaction with Pt (SEt ₂ ) Cl ₂ yields a bisphenylpyridyl complex in a yield of 30%. Is to get. However, this production method has problems that the method for synthesizing the metal complex is complicated and the yield is low.
International Publication No. 2000/57676 Pamphlet Appl. Phys. Lett., 75, 4, pp. 1999 Inorg. Chem., 35, 4833, 1996

  It is an object of the present invention to provide a method for producing a metal complex, which can produce a metal complex easily and with a higher yield than conventional methods.

  As a result of intensive studies by the present inventors, it was found that by using a compound having a partial structure represented by the following formula (1), a metal complex, particularly a platinum complex, can be produced efficiently, and the present invention has been achieved. .

That is, the gist of the present invention is to produce a metal complex characterized in that it is produced using a compound having a partial structure represented by the following formula (1):
A metal complex produced by the production method,
And
An organic electroluminescent device having an anode, a cathode, and an organic layer provided between the anode and the cathode, wherein the organic layer contains the metal complex,
Exist.

(In the formula (1), M represents a metal element selected from the fourth to seventh periods of metals of the Periodic Table ^.X 11 ^{to X 26} each independently represent a hydrogen atom or a ^{substituent, X 11} at least one of to X ²⁶ is a halogen atom.)

  In this specification, unless otherwise specified, the term “periodic table” refers to a long-period periodic table.

  If it is a manufacturing method of the metal complex of this invention using the compound which has the partial structure represented by said Formula (1), the compound which has the partial structure represented by Formula (1), and desired coordination in the suitable solvent The metal complex having the desired ligand can be obtained simply by dissolving and reacting with the child compound, and the number of reaction steps is less than that of the conventional method, and the metal complex can be easily produced. In addition, the yield is improved as compared with the conventional method.

  According to the present invention, a metal complex having excellent light emission characteristics can be produced by selecting a ligand to be reacted, and an organic electric field with high luminous efficiency can be produced using the metal complex thus produced. It becomes possible to manufacture the light emitting element industrially advantageously.

  DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described in detail below. However, the description of constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is specified by these contents. is not.

[Method for producing metal complex]
The method for producing a metal complex of the present invention comprises producing a metal complex using a compound having a partial structure represented by the following formula (1) (hereinafter sometimes referred to as “compound of formula (1)”). It is characterized by.

(In the formula (1), M represents a metal element selected from the fourth to seventh periods of metals of the Periodic Table ^.X 11 ^{to X 26} each independently represent a hydrogen atom or a ^{substituent, X 11} at least one of to X ²⁶ is a halogen atom.)

  Specifically, by reacting a desired ligand with the compound of the formula (1) and replacing the ligand coordinated with the metal element M of the compound of the formula (1), this is introduced, A metal complex in which a desired ligand is coordinated to the metal element M is obtained. This reaction can usually proceed smoothly by mixing and dissolving the compound of formula (1) and the desired ligand compound to be introduced in an appropriate solvent and heating.

<Compound of formula (1)>
In the formula (1), M is a metal element selected from metals in the 4th to 7th periods of the periodic table, and since M is obtained, M is the 7th period in the 4th to 7th periods of the periodic table. ˜13 elements are preferable, and among them, Cu, Zn, Ru, Rh, Pd, Ag, Cd, Re, Os, Ir, Pt, Au are preferable, and Os, Ir, Pt, Au is preferable, and Pt is particularly preferable.

X ¹¹ to X ²⁶ each independently represent a hydrogen atom or a ^substituent, at least one of X 11 ^{to X 26} is a halogen atom. X ^{11 to} X ²⁶ may be the same or different.
When X ^{11 to} X ²⁶ are substituents, examples of the substituent include the following.

An alkyl group which may have a substituent (preferably a linear or branched alkyl group having 1 to 8 carbon atoms which may have a substituent, such as a methyl group, an ethyl group, n- (Propyl group, 2-propyl group, n-butyl group, isobutyl group, tert-butyl group, etc.)
An alkenyl group which may have a substituent (preferably an alkenyl group having 2 to 9 carbon atoms which may have a substituent, for example, a vinyl group, an allyl group, a 1-butenyl group, etc. )
An alkynyl group which may have a substituent (preferably an alkynyl group having 2 to 9 carbon atoms which may have a substituent, such as an ethynyl group and a propargyl group).
Aralkyl group which may have a substituent (preferably, an aralkyl group having 7 to 15 carbon atoms which may have a substituent, such as benzyl group).
An acyl group which may have a substituent (preferably an acyl group having 1 to 10 carbon atoms which may have a substituent, such as a formyl group, an acetyl group and a benzoyl group. )
An alkoxycarbonyl group which may have a substituent (preferably an alkoxycarbonyl group having 2 to 10 carbon atoms which may have a substituent, such as a methoxycarbonyl group and an ethoxycarbonyl group. .)
An alkylcarbonyloxy group which may have a substituent (preferably an alkylcarbonyloxy group having 2 to 10 carbon atoms which may have a substituent, such as an acetoxy group).
Halogen atoms (including fluorine, chlorine, bromine and iodine atoms)
Carboxy group An aromatic hydrocarbon group which may have a substituent (for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, which may have a substituent, And groups derived from 5- or 6-membered monocyclic rings or 2 to 5 condensed rings such as benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, etc.)
An aromatic heterocyclic group which may have a substituent (for example, an optionally substituted furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxa Diazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole Ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, benzoimidazole ring, perimidine ring, quinazoline ring, etc. Groups derived from 2-4 condensed rings And the like.)

  Of the above substituents, an alkyl group and a halogen atom which may have a substituent are preferable, a halogen atom is more preferable, and a fluorine atom is particularly preferable.

  Moreover, as a substituent which each substituent mentioned above may have, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C6-C10 aryloxy group, C1-C1 6 alkylamino groups, aromatic hydrocarbon groups having 6 to 20 carbon atoms, alkylthio groups having 1 to 6 carbon atoms, arylthio groups having 6 to 10 carbon atoms, acyl groups having 2 to 20 carbon atoms, and the like.

X ^{11 to} X ²⁶ may be the same or different, but at least one of X ^{11 to} X ²⁶ is a halogen atom. In particular, it is preferable that all of X ^{11 to} X ²⁶ are halogen atoms, and it is particularly preferable that all of X ^{11 to} X ²⁶ are fluorine atoms.

  In particular, the compound of the formula (1) is preferably a compound represented by the following formula (1-1).

In formula (1-1), M has the same meaning as in formula (1).
n represents the valence of M and is 2 or 3.
X ^{1 to} X ⁶ each independently represent a hydrogen atom or a substituent. Specific examples of the substituent are the same as the specific examples of the substituent of X ^{11 to} X ²⁶ in the above formula (1), and preferable ones are also the same.

Moreover, n pieces of X ^{1 to} X ⁶ existing in the molecule may be the same or different. Note that at least one of n X ^{1 to} X ⁶ present in the molecule is a halogen atom.

  The molecular weight of the compound of the formula (1) is preferably 350 or more, more preferably 400 or more, usually 3500 or less, preferably 2000 or less, more preferably 1200 or less, particularly preferably 800 or less, including its substituents. . A smaller molecular weight is preferable in terms of use efficiency in the production process.

  In addition, the compound of Formula (1) is described in Bull. Chem. Soc. Jpn., 54, 1978, 1981.

  Specific examples of the compound of the formula (1) are shown below, but the compound of the formula (1) is not limited to these.

Among these, those having a trifluoromethyl group as a ligand, in particular, X ^{11 to} X ¹³ , X ^{14 to} X ¹⁶ , X ^{21 to} X ²³ or X ^{24 to} X ²⁶ in formula (1) are each a fluorine atom. Therefore, a trifluoromethyl group is preferable. By having a trifluoromethyl group, it is considered that the ligand is easily detached from the central metal M and becomes a compound that is easily substituted with another ligand. In particular, the compound represented by the following formula is considered to be a compound that has a trifluoromethyl group in the ligand, so that the ligand is easily removed from the central metal Pt and is easily substituted by another ligand. .

<Solvent>
As the solvent used for the reaction, various solvents are applicable and are not particularly limited. For example, aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, and tetralin; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, and trichlorobenzene; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole , Phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole and other aromatic ethers; phenyl acetate, phenyl propionate, methyl benzoate, benzoic acid Aromatic esters such as ethyl, propyl benzoate and n-butyl benzoate; ketones having an alicyclic ring such as cyclohexanone and cyclooctanone; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; cyclohexanol and cyclooctano Alcohol having an alicyclic ring such as but; aliphatic alcohol such as butanol, hexanol, glycerin, ethylene glycol, propylene glycol; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA), methoxyethanol Aliphatic solvents such as ethoxyethanol and methoxypropanol; organic solvents such as aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; and water.

  In terms of the solubility of the reaction substrate, the stabilization of metal ions, etc., the reaction solvent preferably contains a polar solvent, particularly preferably contains a solvent having an alcoholic OH group, preferably methoxyethanol, Aliphatic ethers such as ethoxyethanol and methoxypropanol are preferably used as the reaction solvent.

  These solvents may be used alone or in combination of two or more.

<Ligand>
As a ligand to be reacted with the compound of the formula (1), a desired ligand is used. To produce a luminescent metal complex that can be used for an organic electroluminescent device, for example, MRS Bulletin 32 The ligands described in the volume, page 694, the text of 2007 and cited references are used. Preferably, a ligand containing one or more aromatic hydrocarbon rings or aromatic heterocycles and, if necessary, a monovalent ligand can be used as an auxiliary ligand.

  Although the ligand containing an aromatic hydrocarbon ring or an aromatic heterocyclic ring is illustrated below, the ligand used by this invention is not limited to the following.

  Moreover, as a monovalent ligand, the monoanionic bidentate ligand etc. which are described in Unexamined-Japanese-Patent No. 2005-344124 etc. can be used. Specific examples include an acetylacetonate group, a trifluoroacetyltrifluoroacetonate group, a picolinic acid group, a sulfonylpyridyl group, and a phosphoric acid derivative.

<Reaction ratio and concentration>
If the ratio of the compound of the above formula (1) and the ligand subjected to the reaction is a reaction in which 1 part of the ligand is substituted for the compound of the formula (1), the compound 1 of the formula (1) The amount of ligand is usually 0.1 to 2 parts, preferably 0.8 to 1.5 parts, more preferably 0.9 to 1.1 parts.
Moreover, when 2 parts of ligands are substituted with respect to the compound of Formula (1), it is 1-4 parts normally, Preferably it is 1.6-3 parts, More preferably, 1.8- 2.2 parts.
In addition, when m parts of the ligand are substituted with respect to the compound of the formula (1), the ligand is usually m × 0.5 to m × 2 parts, preferably m × 0.8 to m ×. 1.5 parts, more preferably m × 0.9 to m × 1.1 parts.
However, when replacing two or more parts, two parts may be replaced at a time, or one part may be replaced in two or more stages.
The “part” in the above reaction ratio refers to “mole part”.

  If the concentration of the compound of formula (1) and the ligand in the reaction solution obtained by dissolving the compound of formula (1) and the ligand in the solvent is too high, side reactions may occur, and the concentration is too low. And the reaction efficiency and yield may be lowered and the reaction time may be prolonged. Therefore, the total concentration of the compound of formula (1) and the ligand is 5 to 1000 mg / ml-solvent, particularly 10 It is preferable to set it as -500mg / ml-solvent.

<Reaction conditions, etc.>
The reaction temperature is usually 50 to 250 ° C, preferably 70 to 200 ° C. If the reaction temperature is too low, the reaction proceeds slowly, and if the reaction temperature is too high, the product may be decomposed due to thermal decomposition.

  The reaction time is usually 1 hour to 1 week, preferably 1 hour to 3 days. If the reaction time is too long, it may be inefficient and a by-product may be generated. If it is too short, the reaction may not be completed.

  Usually, in particular, the reaction proceeds without adding a catalyst, an acid, or a base, but various additives may be added for the purpose of improving the efficiency of the reaction. For example, acetic acid, hydrochloric acid, sulfuric acid or the like may be added as the acid. Further, sodium hydroxide, potassium hydroxide, sodium acetate, sodium carbonate, potassium carbonate, cesium carbonate, potassium-t-butoxide, sodium-t-butoxide, or the like may be added as a base. Acids and bases may increase side reactions depending on the substrate.

In this reaction, an acetylacetone derivative is generated during the reaction. By effectively discharging the acetylacetone derivative out of the system, the progress of the reaction can be accelerated.
As the method, there are a method of continuously distilling off the acetylacetone derivative during the reaction, a method of precipitation as a salt with the above-mentioned acid or base, and the like.

<Purification>
As a purification method after completion of the reaction, when a precipitate is formed, it can be purified by filtration and recrystallization. Also in other cases, it can be purified by methods such as recrystallization, column chromatography, distillation, sublimation purification and the like.

[Metal complex]
According to the method for producing a metal complex of the present invention, in the compound of the formula (1), at least a part of the ligand coordinated to the metal element M is substituted with the ligand used in the reaction. Can be manufactured.
According to the present invention, by selecting a ligand to be reacted with the compound of formula (1), it is also possible to obtain a metal complex exhibiting a strong light emission behavior from an excited state. Used as a light-emitting metal complex that can be used for a light-emitting element.

  In use as such a light-emitting metal complex, the metal complex produced by the method of the present invention is particularly preferably a compound represented by the following formula (2), a derivative thereof, or a bisphenylpyridyl derivative.

(In formula (2), X ^{30 to} X ³⁵ each independently represents a hydrogen atom or a substituent.)

In the formula (2), specific examples of the substituent of X ^{30 to} X ³⁵ are the same as the specific examples of the substituent of X ^{11 to} X ²⁶ in the above formula (1), and preferable ones are also the same. As the substituent for X ^{30 to} X ³⁵ , an alkyl group which may have a substituent or a halogen atom is particularly preferable.

  The metal complex obtained by the present invention has a molecular weight of usually 400 or more, preferably 600 or more and usually 2000 or less, preferably 1500 or less.

[Organic electroluminescence device]
The organic electroluminescent device of the present invention is an organic electroluminescent device having an anode, a cathode, and an organic layer provided between the anode and the cathode, wherein the organic layer is produced by the method of the present invention described above. It contains a metal complex. Any organic layer may be used as long as it is a layer between the anode and the cathode.

  Below, the layer structure of the organic electroluminescent element of the present invention using the metal complex produced by the method of the present invention, the general formation method thereof, and the like will be described with reference to FIG.

  FIG. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent device 10 of the present invention using a metal complex produced by the method of the present invention. In FIG. 1, 1 is a substrate, 2 is an anode, and 3 is a positive electrode. Hole injection layer, 4 is a hole transport layer, 5 is a light emitting layer, 6 is a hole blocking layer, 7 is an electron transport layer, 8 is an electron injection layer, and 9 is a cathode.

  In such an organic electroluminescent device, the metal complex produced by the production method of the present invention is preferably used for the light emitting layer, but may be used for other layers. When the metal complex of the present invention is used in a light emitting layer, the metal complex of the present invention is preferably used as a light emitting material contained in the light emitting layer, and the metal complex of the present invention is particularly used with another material as a host material. It is preferably used as a dopant material.

  In addition, in such an organic electroluminescent element 10, when the organic layer between the anode 2 and the cathode 9 is formed by a wet film forming method, the material of each layer described below is dispersed or dissolved in a solvent and applied. A composition for coating may be prepared and a film may be formed using this coating composition.

  Here, the wet film forming method is a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, a capillary coating method, an ink jet method, a screen printing method, and a gravure printing. A method of forming a film using an ink containing a solvent, such as a printing method, a flexographic printing method, and offset printing. Among these wet film forming methods, a die coating method, a roll coating method, a spray coating method, an ink jet method, and a flexographic printing method are preferable from the viewpoint of easy patterning.

  Hereinafter, the substrate, electrodes (anode, cathode), and each layer formed between the electrodes of the organic electroluminescent element of FIG. 1 will be described.

{substrate}
The substrate 1 serves as a support for the organic electroluminescent element, and a quartz or glass plate, a metal plate or a metal foil, a plastic film, a sheet, or the like is used. In particular, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone or the like is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

{anode}
The anode 2 serves to inject holes into the layer on the light emitting layer side.
This anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or It is composed of a conductive polymer such as poly (3-methylthiophene), polypyrrole, or polyaniline.

  In general, the anode 2 is often formed by a sputtering method, a vacuum deposition method, or the like. In addition, when forming the anode 2 using fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, an appropriate binder resin solution It is also possible to form the anode 2 by dispersing it and applying it onto the substrate 1. Furthermore, in the case of a conductive polymer, a thin film can be directly formed on the substrate 1 by electrolytic polymerization, or the anode 2 can be formed by applying a conductive polymer on the substrate 1 (Appl. Phys. Lett. 60, 2711, 1992).

  The anode 2 usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.

  The thickness of the anode 2 varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably about 500 nm or less. When it may be opaque, the thickness of the anode 2 is arbitrary, and the anode 2 may be the same as the substrate 1. Furthermore, it is also possible to laminate different conductive materials on the anode 2 described above.

  For the purpose of removing impurities adhering to the anode 2 and adjusting the ionization potential to improve the hole injection property, the surface of the anode 2 is treated with ultraviolet (UV) / ozone, or with oxygen plasma or argon plasma. It is preferable to do.

{Hole injection layer}
The hole injection layer 3 is a layer that transports holes from the anode 2 to the light emitting layer 5, and is usually formed on the anode 2.
Hereinafter, components contained in the hole injection layer 3 will be described first, and then a method for forming the hole injection layer 3 will be described.

<Material of hole injection layer>
The material of the hole injection layer 3 is contained in the hole injection layer 3. When the hole injection layer 3 is formed by a wet film forming method, a positive hole injection layer forming coating composition (hereinafter sometimes referred to as a “hole injection layer composition”) is added to the positive electrode. The material of the hole injection layer is contained. The material of the hole injection layer 3 is not particularly limited as long as it can form the hole injection layer 3. However, a polymer and an electron accepting compound are usually used as the material for the hole injection layer 3. Furthermore, other components may be used as the material for the hole injection layer 3. Hereinafter, materials of these hole injection layers will be described.

(polymer)
The kind of the polymer used as the material for the hole injection layer 3 is arbitrary as long as the effects of the present invention are not significantly impaired. However, among them, a polymer having a hole transporting property (a high molecular weight hole transporting compound, hereinafter referred to as “hole transporting polymer” as appropriate) is preferable. From this viewpoint, ionization of 4.5 eV to 5.5 eV is preferable. A compound having a potential is preferable. The ionization potential is defined as the energy required to emit electrons at the HOMO (highest occupied molecular orbital) level of a material to the vacuum level, and can be measured directly by photoelectron spectroscopy or electrochemically. It is also obtained by correcting the oxidized potential with respect to the reference electrode. In the case of the latter method, for example, when a saturated sweet potato electrode (SCE) is used as a reference electrode, it is represented by the following formula (“Molecular Semiconductors”, Springer-Verlag, page 98, 1985).
Ionization potential = oxidation potential (vs. SCE) + 4.3 eV

  The weight average molecular weight of the hole transporting polymer used as the material of the hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1000 or more, preferably 2000 or more, more preferably 3000 or more, Usually, it is 500,000 or less, preferably 200,000 or less, more preferably 100,000 or less.

  Examples of the hole transporting polymer include aromatic amine compounds, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, and the like. Of these, aromatic amine compounds are preferred from the viewpoints of amorphousness, solubility in solvents, and visible light transmittance.

  Of the aromatic amine compounds, aromatic tertiary amine compounds are particularly preferable. In addition, the aromatic tertiary amine compound here is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine. The type of the aromatic tertiary amine compound is not particularly limited, but a polymer compound having a weight average molecular weight of 1,000 or more and 1,000,000 or less is more preferable from the viewpoint of the surface smoothing effect.

  Only 1 type may be used for a positive hole transport polymer, and it may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the hole transporting polymer in the hole injection layer 3 is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 10% by weight or more, preferably in terms of the weight percentage with respect to the whole hole injection layer 3. Is 30% by weight or more, usually 99.9% by weight or less, preferably 99% by weight or less. In addition, when using 2 or more types of polymers together, it is preferable that these total content is contained in the said range.

(Electron-accepting compound)
The kind of the electron-accepting compound used as the material for the hole injection layer 3 is arbitrary as long as the effects of the present invention are not significantly impaired. Examples thereof include onium salts substituted with an organic group such as 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate and triphenylsulfonium tetrafluoroborate; No. 251067), high-valent inorganic compounds such as ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; aromatic boron compounds such as tris (pentafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-31365); fullerene derivatives ; Iodine etc. are mentioned.

  Of the above compounds, an onium salt substituted with an organic group is preferable in terms of having strong oxidizing power, and an inorganic compound having a high valence is preferable, and an onium salt substituted with an organic group in terms of being soluble in various solvents, A cyano compound and an aromatic boron compound are preferable. Furthermore, an onium salt substituted with an organic group is most preferable from the viewpoint of achieving both strong oxidizing power and high solubility.

  As a material for the hole injection layer 3, any one of the electron-accepting compounds may be used alone, or two or more may be used in any combination and ratio.

  The content of the electron-accepting compound in the hole injection layer 3 and the composition for hole injection layer is arbitrary as long as the effects of the present invention are not significantly impaired. The value relative to the compound is usually 0.1% by weight or more, preferably 1% by weight or more, and usually 100% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. A larger amount of the electron-accepting compound is preferable because it is more easily insolubilized, and can be insolubilized in a short time. However, if it is excessively large, the film formability is lowered, and the charge injection / transport property is lowered. There is a fear. In addition, when using together 2 or more types of electron-accepting compounds, it is made for the total content of these to be contained in the said range.

(Low molecular weight hole transport compound)
As a material for the hole injection layer 3, it is preferable to use a low molecular weight hole transporting compound as necessary. The low molecular weight hole transporting compound can be appropriately selected from various compounds conventionally used as a hole injecting / transporting thin film forming material in an organic electroluminescence device. Among them, those having high solvent solubility are preferable.

  Preferable examples of the low molecular weight hole transporting compound include aromatic amine compounds. Of these, aromatic tertiary amine compounds are particularly preferred.

  The molecular weight of the low molecular weight hole transporting compound is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 200 or more, preferably 400 or more, more preferably 600 or more, and usually 5000 or less. The range is preferably 3000 or less, more preferably 2000 or less, still more preferably 1700 or less, and particularly preferably 1400 or less. If the molecular weight is too small, the heat resistance tends to be low, whereas if the molecular weight of the low molecular weight hole transporting compound is too large, synthesis and purification tend to be difficult.

  In addition, a low molecular weight hole transportable compound may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

(Other ingredients)
As a material for the hole injection layer 3, in addition to the above-described hole transporting polymer, electron accepting compound, and low molecular weight hole transporting compound, in addition to the above-described hole transporting polymer, other components, as long as the effects of the present invention are not significantly impaired. May be included. Examples of other components include various light emitting materials, electron transporting compounds, binders, resins, and coating property improving agents. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

<Formation of hole injection layer>
When the hole injection layer 3 is formed by a wet film forming method, the above-described material is dissolved in an appropriate solvent to prepare a coating composition, which is applied and formed into a film. Vapor deposition or other methods may be used to form the hole injection layer 3, but the hole injection layer 3 is preferably formed by a wet film formation method.

  When the hole injection layer 3 is formed by a wet film formation method, any solvent can be used as the hole injection layer solvent to be included in the hole injection layer composition as long as the hole injection layer 3 can be formed. Can be used. However, at least one of the materials of the hole injection layer 3 such as the above-described hole transporting polymer, electron accepting compound, and low molecular weight hole transporting compound used as necessary, particularly two or more, particularly Is preferably capable of dissolving all materials. Specifically, the hole-transporting polymer is usually 0.005% by weight or more, preferably 0.5% by weight or more, and particularly preferably 1% by weight or more at room temperature and normal pressure. It is preferable to dissolve the functional compound in an amount of usually 0.001% by weight or more, particularly 0.1% by weight or more, and particularly 0.2% by weight or more.

  As the hole injection layer solvent, a hydrophobic solvent is preferably used, and preferred solvents include ether solvents, ester solvents, aromatic hydrocarbon solvents, and amide solvents. Specifically, examples of the ether solvent include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1, 3 -Aromatic ethers such as dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole; ethyl acetate, n-butyl acetate, Aliphatic esters such as ethyl lactate and n-butyl lactate; Aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate; benzene, toluene, xylene, etc. Aromatic carbonization Motokei solvent; N, N-dimethylformamide, N, N-amide solvent of dimethylacetamide and the like; dimethyl sulfoxide and the like. Any one of these may be used alone, or two or more thereof may be used in any combination and ratio.

  However, aromatic hydrocarbon solvents such as benzene, toluene, and xylene have a low ability to dissolve the electron-accepting compound and the polymer, and are therefore preferably used in a mixture with an ether solvent and an ester solvent.

  The ratio of the hole injection layer solvent to the hole injection layer composition is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50%. It is in the range of not less than weight, usually not more than 99.999% by weight, preferably not more than 99.99% by weight, and more preferably not more than 99.9% by weight. In addition, when mixing and using 2 or more types of solvents as a solvent for positive hole injection layers, it is made for the sum total of these solvents to satisfy | fill this range.

  After the application / film formation of the composition for hole injection layer, the resulting coating film is dried and the solvent for hole injection layer is removed to form a hole injection layer. The method of the wet film forming method is not limited as long as the effect of the present invention is not significantly impaired, and any of the methods described above can be used.

  The thickness of the hole injection layer 3 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

{Hole transport layer}
In FIG. 1, a hole transport layer 4 is formed on the hole injection layer 3.

  The material for forming the hole transport layer 4 includes two or more tertiary amines typified by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl. It has a starburst structure such as an aromatic diamine in which a condensed aromatic ring is substituted with a nitrogen atom (Japanese Patent Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine, etc. Aromatic amine compounds (J. Lumin., 72-74, 985, 1997), aromatic amine compounds consisting of tetramers of triphenylamine (Chem. Commun., 2175, 1996), 2, Spiro compounds such as 2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synth. Metals, 91, 209, 199 Year), 4,4'-N, such as a carbazole derivative such as N'- dicarbazole biphenyl. These compounds may be used individually by 1 type, and may be used in mixture of multiple types as needed.

  In addition to the above compounds, polyarylene ether sulfone (Polym. Adv. Tech.) Containing polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Laid-Open No. 7-53953), and tetraphenylbenzidine as a material for the hole transport layer 4. 7, Vol. 33, 1996).

The hole transport layer 4 is a layer obtained by polymerizing (crosslinking) a compound having a polymerizable group by irradiation with heat and / or active energy rays (ultraviolet rays, electron beams, infrared rays, microwaves, etc.). Preferably there is.
Here, the “polymerizable group” refers to a group that reacts with the same or different groups of other molecules located nearby by irradiation with heat and / or active energy rays to form a new chemical bond. Although it does not specifically limit as a polymeric group, For example, group containing an unsaturated double bond, cyclic ether, benzocyclobutene, etc. is preferable.
Examples of the polymerizable compound include monomers, oligomers, and polymers having these polymerizable groups. Among these, monomers are preferable.

Specific examples of the polymerizable compound, for example, triarylamine derivatives, carbazole derivatives, fluorene derivatives, 2,4,6-triphenyl pyridine derivatives, C ₆₀ derivatives, oligothiophene derivatives, phthalocyanine derivatives, porphyrin derivatives, condensed polycyclic An aromatic derivative, a metal complex derivative, etc. are mentioned. Among these, a compound having a partial structure of triphenylamine and a polymerizable group is particularly preferred because of its high electrochemical stability and charge transportability.

  The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and is usually 300 nm or less, preferably 100 nm or less.

  The hole transport layer 4 may be formed by a vacuum deposition method or a wet film formation method. When forming by the wet film-forming method, the coating composition containing the compound used for the said positive hole transport layer and a solvent is prepared, and this composition is formed into a film. After film formation, the polymerizable compound may be polymerized (crosslinked) by irradiation with heat and / or active energy rays (ultraviolet rays, electron beams, infrared rays, microwaves, etc.).

{Light emitting layer}
When the hole injection layer 3 or the hole transport layer 4 is provided, the light emitting layer 5 is provided on the hole transport layer 4. The light emitting layer 5 is a layer that is excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 between electrodes to which an electric field is applied, and becomes a main light emitting source.

<Light emitting layer material>
The light emitting layer 5 contains at least a material having a light emitting property (light emitting material) as a constituent material, and preferably a compound having a hole transporting property (hole transporting compound) or an electron transport. A compound (electron transporting compound) having the following properties: There is no particular limitation on the light-emitting material, and a material that emits light at a desired light emission wavelength and has favorable light emission efficiency may be used. Usually, a light emitting material is used as a dopant material, and a hole transporting compound or an electron transporting compound is used as a host material.

As described above, the metal complex produced by the production method of the present invention is preferably used for the light emitting layer, and particularly preferably used as the light emitting material. Therefore, the metal complex of the present invention is used as the light emitting material. It is preferable to include.
The light emitting layer 5 preferably contains two or more charge transporting compounds. Furthermore, the light emitting layer 5 may contain other components as long as the effects of the present invention are not significantly impaired. In addition, when forming the light emitting layer 5 with a wet film-forming method, it is preferable to use a low molecular weight material in any case.

(Luminescent material)
As described above, it is preferable to use the metal complex of the present invention as the light emitting material. Hereinafter, the light emitting material used as the material of the light emitting layer when the metal complex of the present invention is used other than the light emitting layer will be described. To do. These light emitting materials may be used in the light emitting layer together with the metal complex of the present invention.

Any known material can be applied as the light emitting material. For example, a fluorescent material or a phosphorescent material may be used, but a phosphorescent material is preferable from the viewpoint of internal quantum efficiency.
For the purpose of improving the solubility in a solvent, it is preferable to reduce the symmetry and rigidity of the molecules of the luminescent material, or to introduce a lipophilic substituent such as an alkyl group.

Hereinafter, examples of the fluorescent light emitting material among the light emitting materials will be described, but the fluorescent light emitting material is not limited to the following examples.
Examples of the fluorescent light-emitting material (blue fluorescent dye) that emits blue light include naphthalene, perylene, pyrene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof.
Examples of the fluorescent light emitting material (green fluorescent dye) that gives green light emission include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Al (C ₉ H ₆ NO) ₃ .
Examples of the fluorescent light emitting material (yellow fluorescent dye) that gives yellow light include rubrene, perimidone derivatives, and the like.
Examples of the fluorescent light-emitting material (red fluorescent dye) that emits red light include, for example, DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) -based compounds, benzopyran derivatives, rhodamine derivatives, Examples thereof include benzothioxanthene derivatives and azabenzothioxanthene.

  Examples of the phosphorescent material include an organometallic complex containing a metal selected from Groups 7 to 11 of the periodic table.

  Preferred examples of the metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold.

  As the ligand of the complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand and a pyridine, pyrazole, phenanthroline, or the like is connected is preferable. A pyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

  Specific examples of the phosphorescent material include tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, tris (2- Phenylpyridine) osmium, tris (2-phenylpyridine) rhenium, octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethyl palladium porphyrin, octaphenyl palladium porphyrin, and the like.

  The molecular weight of the compound used as the light emitting material is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 10,000 or less, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, and usually 100 or more, Preferably it is 200 or more, More preferably, it is 300 or more, More preferably, it is the range of 400 or more. If the molecular weight of the luminescent material is too small, the heat resistance will be significantly reduced, gas generation will be caused, the film quality will be reduced when the film is formed, or the morphology of the organic electroluminescent element will be changed due to migration, etc. Sometimes come. On the other hand, if the molecular weight of the luminescent material is too large, it tends to be difficult to purify the organic compound, or it may take time to dissolve in the solvent.

  In addition, only 1 type may be used for the luminescent material mentioned above, and 2 or more types may be used together by arbitrary combinations and a ratio.

  The ratio of the light emitting material in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.05% by weight or more, preferably 0.3% by weight or more, more preferably 0.5% by weight or more. In addition, it is usually 35% by weight or less, preferably 25% by weight or less, and more preferably 20% by weight or less. If the amount of the light emitting material is too small, uneven light emission may occur. If the amount is too large, the light emission efficiency may be reduced. In addition, when using together 2 or more types of luminescent material, it is made for the total content of these to be contained in the said range.

(Hole transporting compound)
The light emitting layer 5 may contain a hole transporting compound as a constituent material thereof. Here, among the hole transporting compounds, examples of the low molecular weight hole transporting compound include various compounds exemplified as (low molecular weight hole transporting compound) in the hole injection layer 3 described above. For example, two or more condensed aromatic rings containing two or more tertiary amines represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are bonded to the nitrogen atom. Aromatic amine compounds having a starburst structure such as substituted aromatic diamines (Japanese Patent Laid-Open No. 5-234681), 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine, etc. (Journal of Luminescence, 1997, 74, 985, 1997), an aromatic amine compound comprising a tetramer of triphenylamine (Chemical Communicat). ons, 1996, pp. 2175), spiro compounds such as 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene (Synthetic Metals, 1997, Vol. 91, pp. 209) and the like.

  In the light emitting layer 5, only one kind of hole transporting compound may be used, or two or more kinds may be used in any combination and ratio.

  The ratio of the hole transporting compound in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight. In addition, it is usually 65% by weight or less, preferably 50% by weight or less, and more preferably 40% by weight or less. If the amount of the hole transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of hole transportable compounds, it is made for the total content of these to be contained in the said range.

(Electron transporting compound)
The light emitting layer 5 may contain an electron transporting compound as a constituent material thereof. Here, among the electron transporting compounds, examples of low molecular weight electron transporting compounds include 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (BND), 2,5, -Bis (6 '-(2', 2 "-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy), bathophenanthroline (BPhen), 2,9-dimethyl-4,7 -Diphenyl-1,10-phenanthroline (BCP, bathocuproin), 2- (4-biphenylyl) -5- (p-tertiarybutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 4 , 4′-bis (9-carbazole) -biphenyl (CBP), etc. In the light emitting layer 5, only one type of electron transporting compound may be used, or two or more types may be combined arbitrarily. It may be used in combination with so and proportions.

  The ratio of the electron transporting compound in the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more. In addition, it is usually 65% by weight or less, preferably 50% by weight or less, and more preferably 40% by weight or less. If the amount of the electron transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of electron transport compounds, it is made for the total content of these to be contained in the said range.

<Formation of light emitting layer>
When forming the light emitting layer 5 by the wet film-forming method according to the present invention, a coating composition is prepared by dissolving the above materials in an appropriate solvent, and a film is formed using the composition. Note that vapor deposition or other methods may be used to form the light emitting layer 5.

  As the light emitting layer solvent to be contained in the coating composition for forming the light emitting layer 5 by a wet film forming method, any solvent can be used as long as the light emitting layer can be formed. However, those capable of dissolving the light-emitting material, the hole transporting compound, and the electron transporting compound are preferable. Specifically, the solubility of the light-emitting material, the hole transporting compound or the electron transporting compound is usually 0.01% by weight or more, particularly 0.05% by weight or more, particularly 0.1% at room temperature and normal pressure. It is preferable to dissolve by weight% or more.

  As the solvent for the light emitting layer, the same solvents as those exemplified as the solvent for the hole injection layer can be used. These organic solvents may use only 1 type and may use 2 or more types together by arbitrary combinations and ratios.

  The ratio of the solvent for the light emitting layer to the coating composition for forming the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by weight or more, preferably 0.1% by weight. Above, more preferably 0.5% by weight or more, and usually 70% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. In addition, when mixing and using 2 or more types of solvents as a solvent for light emitting layers, it is made for the sum total of these solvents to satisfy | fill this range.

The composition for coating for forming the light emitting layer 5 is applied on the hole injection layer 3 by a wet film formation method when the hole transport layer 4 or the hole transport layer 4 is not present, and after film formation, The obtained coating film is dried and the luminescent layer 5 is formed by removing the luminescent layer solvent. The method of the wet film forming method is not limited as long as the effect of the present invention is not significantly impaired, and any of the methods described above can be adopted.
Further, the light emitting layer 5 may be formed by a conventionally used vacuum deposition method.

  The thickness of the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 3 nm or more, preferably 5 nm or more, and usually 200 nm or less, preferably 100 nm or less. If the thickness of the light emitting layer 5 is too thin, defects may occur in the film, and if it is too thick, the driving voltage may increase.

{Hole blocking layer}
A hole blocking layer 6 may be provided between the light emitting layer 5 and an electron injection layer 8 described later. The hole blocking layer 6 is a layer laminated on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.

  The hole blocking layer 6 has a role of blocking holes moving from the anode 2 from reaching the cathode 9 and a role of efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. Have

  The physical properties required for the material constituting the hole blocking layer 6 include high electron mobility, low hole mobility, a large energy gap (difference between HOMO and LUMO), and excited triplet level (T1). Is high. Examples of the material for the hole blocking layer that satisfies such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum, and the like. Mixed-ligand complexes, metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinato) aluminum binuclear metal complexes, distyrylbiphenyl derivatives, etc. Triazole derivatives such as styryl compounds (JP-A-11-242996), 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole (JP-A-7 -41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. That. Further, a compound having at least one pyridine ring substituted at positions 2, 4, and 6 described in International Publication No. 2005-022962 is also preferable as a material for the hole blocking layer 6.

  In addition, the material of the hole-blocking layer 6 may use only 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  There is no restriction | limiting in the formation method of the hole-blocking layer 6. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

  The thickness of the hole blocking layer 6 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

{Electron transport layer}
An electron transport layer 7 may be provided between the light emitting layer 5 and an electron injection layer 8 described later.
The electron transport layer 7 is provided for the purpose of further improving the light emission efficiency of the device, and efficiently transports electrons injected from the cathode 9 between the electrodes to which an electric field is applied in the direction of the light emitting layer 5. Formed from a compound capable of

  As an electron transport compound used for the electron transport layer 7, usually, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and the injected electrons are transported efficiently with high electron mobility. The compound which can be used is used. Examples of the compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives , Distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compounds ( JP-A-6-207169), phenanthroline derivative (JP-A-5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide , N-type zinc sulfide, n-type zinc Such as emissions of zinc, and the like.

  In addition, the material of the electron carrying layer 7 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of the electron carrying layer 7. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

  The thickness of the electron transport layer 7 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

{Electron injection layer}
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the light emitting layer 5. In order to perform electron injection efficiently, the material for forming the electron injection layer 8 is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the film thickness is preferably from 0.1 nm to 5 nm.

  Furthermore, an organic electron transport compound represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium ( (As described in JP-A-10-270171, JP-A-2002-1000047, JP-A-2002-1000048, etc.), it is possible to improve the electron injection / transport properties and achieve excellent film quality. preferable. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.

  In addition, the material of the electron injection layer 8 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of the electron injection layer 8. FIG. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

{cathode}
The cathode 9 plays a role of injecting electrons into a layer (such as the electron injection layer 8 or the light emitting layer 5) on the light emitting layer 5 side.

  As the material of the cathode 9, the material used for the anode 2 can be used. However, in order to perform electron injection efficiently, a metal having a low work function is preferable. For example, tin, magnesium, indium, A suitable metal such as calcium, aluminum, silver, or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

  In addition, the material of the cathode 9 may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The film thickness of the cathode 9 is usually the same as that of the anode 2.

  Further, for the purpose of protecting the cathode 9 made of a low work function metal, it is preferable to further stack a metal layer having a high work function and stable to the atmosphere because the stability of the device is increased. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold and platinum are used. In addition, these materials may be used only by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

{Other layers}
The organic electroluminescent element according to the present invention may have another configuration without departing from the gist thereof. For example, as long as the performance is not impaired, an arbitrary layer may be provided between the anode 2 and the cathode 9 in addition to the layers described above, and an arbitrary layer may be omitted. .

Examples of the layer that may be included include an electron blocking layer.
The electron blocking layer is provided between the hole injection layer 3 or the hole transport layer 4 and the light emitting layer 5 and prevents electrons moving from the light emitting layer 5 from reaching the hole injection layer 3. Thus, the probability of recombination of holes and electrons in the light emitting layer 5 is increased, the excitons generated are confined in the light emitting layer 5, and the holes injected from the hole injection layer 3 are efficiently collected. There is a role to transport in the direction of. In particular, when a phosphorescent material or a blue light emitting material is used as the light emitting material, it is effective to provide an electron blocking layer.

  The characteristics required for the electron blocking layer include high hole transportability, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1). Furthermore, in the present invention, when the light emitting layer 5 is produced by a wet film formation method, the electron blocking layer is also required to be compatible with the wet film formation. Examples of the material used for such an electron blocking layer include a copolymer of dioctylfluorene and triphenylamine typified by F8-TFB (described in International Publication No. 2004/084260).

  In addition, the material of an electron blocking layer may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the formation method of an electron blocking layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

Further, at the interface between the cathode 9 and the light emitting layer 5 or the electron transport layer 7, for example, lithium fluoride (LiF), magnesium fluoride (MgF ₂ ), lithium oxide (Li ₂ O), cesium carbonate (II) (CsCO ₃ ). It is also an effective method for improving the efficiency of the element to insert an ultrathin insulating film (film thickness of 0.1 to 5 nm) formed by the method (Applied Physics Letters, 70, 152, 1997; No. 10-74586; see IEEE Transactions on Electron Devices, 44, 1245, 1997; SID 04 Digest, 154)

  Moreover, in the layer structure demonstrated above, it is also possible to laminate | stack components other than a board | substrate in reverse order. For example, in the case of the layer configuration of FIG. 1, the other components on the substrate 1 are the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, the hole transport layer 4, the positive layer. The hole injection layer 3 and the anode 2 may be provided in this order.

  Furthermore, it is also possible to constitute the organic electroluminescent element according to the present invention by laminating components other than the substrate between two substrates, at least one of which is transparent.

Further, a structure in which a plurality of components (light emitting units) other than the substrate are stacked in a plurality of layers (a structure in which a plurality of light emitting units are stacked) may be employed. In that case, (when the anode is ITO, the cathode is Al, these two layers) interfacial layer between the respective stages (between emission units) Alternatively, for example, a charge consisting of five vanadium oxide (V 2 _{O 5),} etc. When a generation layer (Carrier Generation Layer: CGL) is provided, a barrier between steps is reduced, which is more preferable from the viewpoint of light emission efficiency and driving voltage.

  Furthermore, the organic electroluminescent device according to the present invention may be configured as a single organic electroluminescent device, or may be applied to a configuration in which a plurality of organic electroluminescent devices are arranged in an array. You may apply to the structure by which the cathode is arrange | positioned at XY matrix form.

  Each layer described above may contain components other than those described as materials unless the effects of the present invention are significantly impaired.

{Usage}
The organic electroluminescent element of the present invention can be used for an organic EL display. In this case, the organic electroluminescence device obtained by the present invention is used, for example, described in “Organic EL display” (Ohm, published on August 20, 2004, written by Shizushi Tokito, Chiba Adachi, and Hideyuki Murata). An organic EL display can be formed by a method as described above.

  Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.

[Example 1]
Synthesis of platinum (II)-(2-phenylpyridinato-N, C2) -hexafluoroacetylacetonate (compound 1)

  2-Phenylpyridine (30 mg, 0.06 mmol) was added to a 30 ml ethoxyethanol solution of platinum (II) -hexafluoroacetylacetonate (100 mg, 0.16 mmol), and the reaction solution was reacted at 90 ° C. for 2 hours. After cooling the reaction solution, cold water was added to form a precipitate.

  The precipitate was filtered to obtain 64 mg of an orange solid (compound 1) (yield 99%). The decomposition temperature of this compound (1) was 236 ° C.

¹ H NMR (CDCl ₃ ) δ: 6.23 (s, 1H), 7.11-7.21 (m, 3H), 7.35 (d, J6.8Hz, 1H),
7.43 (d, J7.8Hz, 1H), 7.65 (d, J7.8Hz, 1H), 7.85 (t, J6.8Hz, 1H),
8.66 (d, J5.5Hz, 1H)
¹³ C NMR (CDCl ₃ ) δ: 94.59, 118.70, 121.69, 123.08, 124.84, 129.48, 130.50, 133.83,
139.17,144.33,147.63,167.95,170.92
IR (KBr): 3058,1614,1586,1553,1200
MS (LDI-TOF) Calcd.for C ₁₆ H ₉ F ₆ NO ₂ Pt: 556.02
Found: 555.71
m / z (%) (100, M ⁺ ) Anal.Calcd.for C ₁₈ H ₉ F ₈ NO ₂ Pt: C = 34.54, H = 1.63, N = 2.52
Found: C = 34.41, H = 1.79, N = 2.60

[Comparative Example 1]
Synthesis of platinum (II)-(2-phenylpyridinato-N, C2) -hexafluoroacetylacetonate (compound 1)
K ₂ PtCl ₄ (560 mg, 1.35 mmol) and 2-phenylpyridine (233, mg 1.5 mmol) were dissolved in glacial acetic acid (250 ml) and reacted at 80 ° C. until the red color of the reaction solution disappeared for 3 days. The precipitate produced by this reaction was filtered to obtain 320 mg of μ-Cl ₂ platinum (II)-(2-phenylpyridinato-N, C2) yellow solid (yield 64%). The obtained crystals (solid) were used in the next step without further purification.

The obtained μ-Cl ₂ platinum (II)-(2-phenylpyridinato-N, C2) (90 mg, 0.12 mmol) was dissolved in 8 ml of ethoxyethanol, hexafluoroacetylacetone (62 mg, 0.12 mmol) and Na ₂ CO ₃ (85 mg 0.80 mmol) was added and stirred at room temperature for 2 days. The precipitate thus formed was filtered, and silica gel chromatography (hexane / ethyl acetate = 2/1) gave 4 mg of an orange solid (yield 6%).
NMR confirmed that it was the same as Compound 1 prepared in Example 1.

[Example 2]
Synthesis of platinum (II) (2- (2,4-difluorophenyl) -4-dimethylaminopyridinato-N, C2) -hexafluoroacetylacetonate (compound 2)

<Synthesis of 2-bromo-4-dimethylaminopyridine>
Boron trifluoride etherate (3.1 ml, 22 mmol) was added to a 150 ml tetrahydrofuran solution of 4-dimethylaminopyridine (2.5 g, 20 mmol) at 0 ° C. The reaction was stirred for 30 minutes and then cooled to -78 ° C. N-Butyllithium (32.0 mmol, 1.60 M hexane solution) was added to the reaction solution and stirred for 30 minutes, and then bromine (32.0 mmol, 1.65 ml) was added. The reaction was slowly warmed to room temperature and stirred overnight. To the reaction solution are added a saturated aqueous sodium carbonate solution and ethyl acetate, and the mixture is separated, and the ethyl acetate layer is dehydrated and concentrated, and 2-bromo-4-dimethylamino is purified by column chromatography (hexane / ethyl acetate = 5/1). 0.98 g (55% yield) of pyridine was obtained as a white solid. The melting point of this product was 60 ° C.

¹ H NMR (CDCl ₃ ) δ: 3.00 (s, 6H), 6.44 (dd, J6.0, 2.5Hz, 1H), 6.64 (d, J2.5Hz, 1H),
7.94 (d, J6.0Hz, 1H)
¹³ C NMR (CDCl ₃ ): 39.20, 106.14, 109.16, 142.97, 149.23, 155.68
IR (KBr): 2927,2803,1918,1590,1519,1070
m / z (%) (100, M ⁺ ) Anal.Calcd.for C ₇ H ₉ BrN ₂ : C = 41.82, H = 4.51, N = 13.93
Found: C = 42.01, H = 4.33, N = 14.15

<Synthesis of 2- (2,4-difluorophenyl) -4-dimethylaminopyridine>
2-Bromo-4-dimethylaminopyridine (250 mg, 1.25 mmol) and difluorophenylboronic acid (0.60 g, 3.8 mmol) were dissolved in 8 ml of toluene, and Pd (CH ₃ COO) ₂ (10 mg, 0.04 mmol, 0.5 mol) was dissolved. %) And 2M K ₃ PO ₄ (1,25 ml, 2.5 mmol) aqueous solution were added and the mixture was refluxed for 3 days. The reaction was quenched with 10% hydrochloric acid and extracted with chloroform. After washing with saturated brine, dehydration, concentration, and column chromatography (hexane / ethyl acetate = 3/1), 260 mg of 2- (2,4-difluorophenyl) -4-dimethylaminopyridine (yield 92%) Was obtained as white crystals. The melting point of this product was 54 to 55 ° C.

¹ H NMR (CDCl ₃ ) δ: 3.04 (s, 6H), 6.48 (dd, J6.0, 2.7 Hz, 1H), 6.48-6.99 (m, 3H),
7.90 (dd, J6.8Hz, 1H), 8.31 (d, J6.0Hz, 1H)
¹³ C NMR (CDCl ₃ ): 39.17, 104.10, 105.50, 107.10, 111.61, 132.11, 149.60, 152.58, 154.57
IR (KBr): 2926,1609,1549,1505,1268
m / z (%) (100, M ⁺ ) Anal.Calcd.for C ₁₃ H ₁₂ F ₂ N ₂ : C = 66.66, H = 5.16, N = 11.96
Found: C = 66.59, H = 4.98, N = 11.88

<Synthesis of Platinum (II) (2- (2,4-Difluorophenyl) -4-dimethylaminopyridinato-N, C2) -hexafluoroacetylacetonate (Compound 2)>
2- (2,4-difluorophenyl) -4-dimethylaminopyridine (30 mg, 0.06 mmol) was added to a 30 ml ethoxyethanol solution of platinum (II) -hexafluoroacetylacetonate (100 mg, 0.16 mmol), and the reaction solution Was reacted at 90 ° C. for 2 hours. After cooling the reaction solution, cold water was added to form a precipitate. The precipitate was filtered and recrystallized from a hexane / dichloromethane mixed solution to obtain 55 mg of a red solid (compound 2) (yield 54%). The decomposition temperature of this product was 283 ° C.

¹ H NMR (CDCl ₃ ) δ: 3.14 (s, 6H), 6.19 (s, 1H), 6.34 (dd, J7.0, 3.1 Hz, 1H),
6.55 (ddd, J12.4, 9.1, 2.3Hz, 1H), 6.75 (dd, J8.2, 2.3Hz, 1H),
7.14 (t, J3.1Hz, 1H), 8.06 (d, J7.0Hz, 1H)
¹³ C NMR (CDCl ₃ ): 39.44, 94.66, 100.24, 103.67, 104.50, 112.55, 136.39, 145.93, 155.54,
162.75,170.50
IR (KBr): 2938, 2815, 1625, 1515, 1409, 1269
MS (LDI-TOF) Calcd.for C ₁₈ H ₁₂ F ₈ N ₂ O ₂ Pt: 635.04
Found: 634.96
m / z (%) (100, M ⁺ ) Anal.Calcd.for C ₁₈ H ₁₂ F ₈ N ₂ O ₂ Pt: C = 34.03, H = 1.90, N = 4.41
Found: C = 34.10, H = 2.20, N = 4.44

[Comparative Example 2]
Synthesis of platinum (II) (2- (2,4-difluorophenyl) -4-dimethylaminopyridinato-N, C2) -hexafluoroacetylacetonate (compound 2)
K ₂ PtCl ₄ (225 mg, 0.5 mmol) and 2- (2,4-difluorophenyl) -4-dimethylaminopyridine (200 mg, 0.8 mmol) were dissolved in glacial acetic acid (100 ml), and the mixture was reacted at 80 ° C. The reaction was continued for 3 days until the red color disappeared. The resulting precipitate was filtered, washed with water, acetone, diethyl ether, 150 mg μ-Cl ₂ platinum (II)-(2- (2,4-difluorophenyl) -4-dimethylaminopyridinato-N , C2) was obtained as a gray solid (yield 64%). The obtained crystals were used in the next step without further purification.

The obtained μ-Cl ₂ platinum (II)-(2- (2,4-difluorophenyl) -4-dimethylaminopyridinato-N, C2) (50 mg, 0.05 mmol) was dissolved in 8 ml of ethoxyethanol, Hexafluoroacetylacetone (40 mg, 0.25 mmol) and Na ₂ CO ₃ (85 mg, 0.80 mmol) were added, and the mixture was stirred at room temperature for 2 days. The produced precipitate was filtered, and silica gel chromatography (hexane / ethyl acetate = 5/1) gave 8 mg of a red solid (yield 25%).
It was confirmed by NMR that it was the same as compound 2 produced in Example 2.

[Example 3]
Synthesis of Cis-platinum (II) (2-diphenylpyridinato-N, C2) (compound 3)

  2-phenylpyridine (18 mg, 0.12 mmol) was added to an 8 ml ethoxyethanol solution of compound 1 (33 mg, 0.06 mmol), and the reaction solution was reacted at 90 ° C. for 1 day. The resulting precipitate was extracted with dichloromethane, dehydrated and concentrated, and then a red solid (compound 3) was obtained by column chromatography (yield 55%).

¹ H NMR (CDCl ₃ ) δ: 7.15 (td, J7.4, 0.9 Hz, 2H), 7.29-7.30 (m, 4H), 7.64 (dd, J7.8, 1.4 Hz, 2H),
7.88 (dd, J5.3, 1.4Hz, 4H), 8.18 (d, J7.4Hz, 2H), 8.77 (d, J5.3Hz, 2H)

[Example 4]
Synthesis of platinum (II) (2- (2,4-difluorophenyl) -4-dimethylaminopyridinato-N, C2) -acetylacetonate (compound 4)

  In Example 3, platinum (II) (2- (2,4-difluorophenyl) -4 was used in the same manner except that compound 2 was used instead of compound 1, and acetylacetone was used instead of 2-phenylpyridine. -Dimethylaminopyridinato-N, C2) -acetylacetonate was synthesized. The decomposition temperature of this product was 283 ° C.

¹ H-NMR (CDCl ₃ ) δ: 1.97 (s, 6H), 3.12 (s, 6H), 5.45 (s, 1H), 6.35 (dd, J6.9, 2.7Hz, 1H),
6.52 (ddd, J12.5, 9.3, 2.6Hz, 1H), 7.07 (dd, J8.7, 2.6Hz, 1H),
7.18 (t, J2.7Hz, 1H), 8.42 (d, J6.9Hz, 1H)
¹³ C NMR (CDCl ₃ ) δ: 27.12, 28.07, 39.45, 98.92, 102.47, 103.30, 104.49, 112.47, 145.90,
155.31,163.51,184.09,185.37
IR (KBr): 2923,1625,1570,1519,1405,1248
MS (LDI-TOF) Calcd.for C ₁₈ H ₁₈ F ₂ N ₂ O ₂ Pt: 527.10
Found: 527.23
m / z (%) (100, M ⁺ ) .Anal.Calcd.for C ₁₈ H ₁₈ F ₂ N ₂ O ₂ Pt: C = 40.99, H = 3.44, N = 5.31
Found: C = 40.91, H = 3.34, N = 5.33

[Example 5]
Synthesis of platinum (II) (2- (2,4-difluorophenyl) -4-dimethylaminopyridinato-N, C2) -dipivaloylmethane (compound 5)

  In Example 3, platinum (II) (2- (2,4-difluoro) was prepared in the same manner except that compound 2 was used instead of compound 1 and dipivaloylmethane was used instead of 2-phenylpyridine. Phenyl) -4-dimethylaminopyridinato-N, C2) -dipivaloylmethane was synthesized.

¹ H-NMR (CDCl ₃ ) δ: 1.26 (d, J4.6Hz, 18H), 3.12 (s, 6H), 5.78 (s, 1H), 6.38 (dd, J6.9, 2.9Hz, 1H),
6.52 (ddd, J12.4, 8.9, 2.4Hz, 1H), 7.09 (dd, J8.9, 2.4Hz, 1H),
7.19 (t, J2.9Hz, 1H), 8.44 (d, J6.9Hz, 1H)

[Example 6]
Synthesis of platinum (II)-(2-phenylpyridinato-N, C2) -acetylacetonate (compound 6)

Platinum (II)-(2-phenylpyridinato-N, C2) -hexafluoroacetylacetonate (20 mg, 0.036 mmol) is dissolved in 5 ml of ethoxyethanol, acetylacetone (4 mg, 0.040 mmol) and Na ₂ CO ₃ ( 15 mg, 0.14 mmol) was added and the reaction was stirred at 90 ° C. for 2 hours. After cooling the reaction solution, water was added, followed by extraction with dichloromethane. After dehydration and concentration, 10 mg (yield 61%) of platinum (II)-(2-phenylpyridinato-N, C2) -acetylacetonate was obtained as a yellow solid by column chromatography (hexane / ethyl acetate = 2/1) Got as.

¹ H NMR (CDCl ₃ ) δ: 2.00 (s, 6H), 5.47 (s, H), 7.07-7.11 (m, 2H),
7.20 (ddd, 15.1, 7.8, 1.4Hz, 1H), 7.43 (ddJ7.8, 0.9Hz, 1H),
7.59-7.62 (m, 2H), 7.79 (ddd, J15.6, 7.8, 1.8Hz, 1H),
8.98 (dd, J6.0, 0.9Hz, 1H).
MS (LDI-TOF) Calcd.for C ₁₆ H ₁₅ NO ₂ Pt: 448.08
Found: 447.91

[Measurement of Luminescence in Solution of Compound 4, Compound 5 and Compound 6]
Compound 4, Compound 5 and Compound 6 were each dissolved in chloroform to prepare a solution having a concentration of 1 × 10 ⁻⁵ (mol / l). The obtained solution was excited with a light having a wavelength of 360 nm using a spectrophotometer FP-6200 (manufactured by JASCO), and an emission spectrum was measured. The results are shown in FIG.
Of these compounds, both Compound 4 and Compound 5 emitted blue light, indicating that they can be used as blue light-emitting materials required for display materials such as organic electroluminescent devices.

It is typical sectional drawing which shows an example of the organic electroluminescent element of this invention. 3 is a chart showing emission spectra of a chloroform solution of compound 4, compound 5 and compound 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electroluminescent device

Claims (6)

The manufacturing method of the metal complex characterized by manufacturing using the compound which has a partial structure represented by following formula (1).

(In the formula (1), M represents a metal element selected from the fourth to seventh periods of metals of the Periodic Table ^.X 11 ^{to X 26} each independently represent a hydrogen atom or a ^{substituent, X 11} at least one of to X ²⁶ is a halogen atom.)   In the said Formula (1), M is platinum, The manufacturing method of the metal complex of Claim 1 characterized by the above-mentioned. The method for producing a metal complex according to claim 1, wherein all of X ^{11 to} X ²⁶ in the formula (1) are halogen atoms. The metal complex produced by using a compound having a partial structure represented by the above formula (1) is a compound represented by the following formula (2) or a derivative thereof: The manufacturing method of the metal complex as described in any one of these.

(In formula (2), X ^{30 to} X ³⁵ each independently represents a hydrogen atom or a substituent.)   The metal complex manufactured by the manufacturing method of the metal complex as described in any one of Claims 1 thru | or 4.   An organic electroluminescent device having an anode, a cathode, and an organic layer provided between the anode and the cathode, wherein the organic layer contains the metal complex according to claim 5. Light emitting element.

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