JP2006290781A - Iridium complex having good solubility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an iridium complex capable of readily carrying out coating by coating method and achieving high luminous efficiency and low voltage. <P>SOLUTION: The iridium complex is represented by general formula (1) (wherein R<SP>1</SP>-R<SP>8</SP>are each a hydrogen atom, an alkyl group, a halogen atom, an alkoxy group, a halogenated alkyl group, a dialkylamino group or a diarylamino group and each substituent may be bonded to other substituent and R<SP>9</SP>and R<SP>10</SP>are each an alkyl group, an aryl group, an alkoxy group or a halogenated alkyl group and R<SP>11</SP>is a hydrogen atom, an alkyl group, an aryl group or a halogenated alkyl group and R<SP>9</SP>, R<SP>10</SP>and R<SP>11</SP>may be each a polymerizable group or a group obtained by polymerizing the polymerizable group, with the proviso that at least one of R<SP>1</SP>to R<SP>11</SP>is ≥5C alkyl group or alkoxy group; n is an integer of 1 or 2 and n1 is an integer of 1 or 2 and the sum of n and n1 is 3). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an iridium complex having good solubility in a solvent.

  Today, research and development on various display elements is active. Among them, organic electroluminescent elements (hereinafter abbreviated as “organic EL elements”) can obtain high-luminance light emission at a low voltage. It is attracting attention as a display element for the next generation.

  Organic EL elements have low applied voltage, low power consumption, can be miniaturized, are surface emitting, and can also emit three primary colors, so there is a lot of research into applying such organic EL elements to multicolor displays. Has been. However, in order to develop a highly functional multi-color display, it is necessary to improve the light emitting element characteristics and efficiency of each of the three primary colors of red, green, and blue. There is a need for improved luminous efficiency.

As a means for improving the light emitting device characteristics of the organic EL device, it has been proposed to use a phosphorescent material for the light emitting layer of the organic EL device. In current excitation by recombination of electrons and holes, a total of four eigenstates of three triplet eigenstates and one singlet eigenstate occur with equal probability by recombination according to the spin statistics law. Therefore, singlet excitons and triplet excitons occur with a probability of 1: 3. Thus, in the organic EL element by current excitation, the reason why phosphorescent light-emitting materials are particularly attracting attention is that high luminous efficiency can be expected in principle. Until now, organic EL devices have taken out fluorescence when transitioning from a singlet exciton to a ground state as luminescence, but in principle, the luminescence yield is 25% of the number of excitons generated. This was the theoretical upper limit. However, if phosphorescence from excitons generated from triplets is used, a yield of at least three times is expected in principle, and transition due to intersystem crossing from singlet to triplet with high energy is considered. In combination, a 100% light emission yield of 4 times can be expected in principle.
Examples of such phosphorescent materials include bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium acetylacetonate (Ir (ppy) ₂ (acac)) represented by the following formula, and tris represented by the following formula: Ortho-metalated iridium complexes including (2-phenylpyridinato-N, C ^{2 ′} ) (Ir (ppy) ₃ ) iridium are widely known.

The light emission of the phosphorescent light-emitting material (phosphorescent dopant) depends on the host material. The basic performance required for the host material is that it has a hole transport property and an electron transport property, and the triplet state of the host material. The energy level is higher than the triplet energy of the phosphorescent dopant, and in general, CBP (4,4′-bis (carbazol-9-yl) biphenyl), which is a low molecular material, is preferably used.
Phosphorescent devices using such low-molecular materials can easily optimize the layer structure, and thus can be expected to increase efficiency and prolong the lifetime. There is a problem that agglomeration occurs and the device deteriorates, which greatly affects the device life. Furthermore, there is a problem that an element must be manufactured by a vapor deposition process, a large vapor deposition apparatus is required and the cost is high, and further, it is difficult to increase the area of the base material. As a method that can be manufactured at a low cost and can produce a large area display as compared with a vacuum deposition method, there is a coating method in which a substrate is used for coating with a solvent. However, even if an attempt is made to prepare a coating solution by dissolving or dispersing a conventional low molecular weight material in a solvent, the solubility and dispersibility are poor, so a uniform and stable coating solution cannot be obtained, and even if film formation is possible Due to the poor stability, it has been difficult to use conventional low molecular weight materials by a coating method.

However, in order to apply an organic EL element as a verification device or a large area display, development of a manufacturing method by a coating method capable of easily forming a stable layer is required. Filmable phosphorescent luminescent materials have been developed. As a method for this, for example, a polymer host such as PVCz (polyvinylcarbazole) and Ir (ppy) ₃ (tris (2-phenylpyridinate-N, C ^{2 ′} ) iridium (III) complex) or the like can be used. A method of applying a mixed solution with a molecular phosphorescent guest (Patent Document 1), a method of applying a polymer solution obtained by copolymerizing a monomer of a host molecule and a guest molecule and polymerizing the whole (Non-Patent Document 1, 2) A method of using a dendrimer as a polymer material, arranging a low-molecular phosphorescent guest at the center of a conjugated dendrimer, and applying a mixed solution with a low-molecular host (Non-patent Document 3) has been reported. Yes. In addition, an organic EL element having improved stability against oxygen and water has also been reported (see, for example, Patent Document 2).

  However, in these conventional methods, even if a solution can be easily formed by spin coating, the light emitting characteristics and device lifetime of the obtained light emitting layer are not always sufficient, and the light emission properties and device lifetime are not sufficient. However, there is a demand for the development of materials with improved quality.

J.-S. Lee et.al., Polymer Preprints 2001, 42 (2), p.448-449 (2001) Mitsunori Suzuki, Shizushi Tokito, NHK R & D, No.77, p.34-41 (2003) S.-C.Lo et.al., Adv.Mater., Vol.14, No.13-14, p.975-979 (2002) Japanese Patent Laid-Open No. 2001-257076 Japanese translation of PCT publication No. 2002-543570

  The present invention has been made to solve the above-mentioned problems, and is an organic compound that can be easily coated by a coating method and can realize high luminous efficiency, and organic electroluminescence having high luminous efficiency using the organic compound. It is to provide an element.

In the process of studying an organic EL device that is easy to coat by a coating method and has high luminous efficiency, the present inventors have found that the iridium complex represented by the general formula (1) has excellent solvent solubility and It discovered that it had solvent dispersibility, and completed this invention.
Conventionally, an iridium complex, which is a phosphorescent material, loses phosphorescence in an aggregated state where iridium complex molecules are close to each other because energy exchange occurs between triplet states of the respective molecules. For this reason, it is not suitable to aggregate the iridium complex which is a phosphorescent compound. However, it has been found that by using an iridium compound represented by the following general formula (1) as a host material, not only the solvent solubility is improved, but also high efficiency and low voltage driving are possible.

  The iridium complex according to the present invention has good solvent solubility or solvent dispersibility, and is easily dissolved or dispersed in the solvent. Therefore, by applying the coating liquid containing the iridium complex compound of the present invention on the coating material, the compound can be uniformly dispersed without aggregating in the coating film. Uniform light emission characteristics can be provided in each part of the above. Further, not only higher luminous efficiency can be achieved, but also driving at a lower voltage is possible than in the prior art.

  That is, the present invention relates to an iridium complex represented by the following general formula (1).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom, an alkyl group, a halogen atom, an alkoxy group, a halogenated alkyl group, A dialkylamino group and a diarylamino group, each of which may be bonded to another substituent R ⁹ and R ¹⁰ are each independently an alkyl group, an aryl group, an alkoxy group or a halogenated group; Represents an alkyl group, R ¹¹ represents a hydrogen atom, an alkyl group, an aryl group or a halogenated alkyl group, and R ⁹ , R ¹⁰ and R ¹¹ represent a polymerizable group or a group obtained by polymerizing the polymerizable group. Provided that at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ has 5 or more carbon atoms. Alkyl group, aralkyl group The .n representing the alkoxy group is an integer of 1 or 2, n1 is an integer of 1 or 2, the sum of n and n1 is 3.)

  Since the iridium complex according to the present invention (hereinafter referred to as the complex of the present invention) has excellent solvent solubility, it can be formed into a film using a paint containing the compound, and is an organic light-emitting device, particularly phosphorescent organic light-emitting device. It is possible to produce the device by coating film formation.

Further, since the complex of the present invention is uniformly dispersed without aggregating in the coating film, when used in an organic EL device, it provides uniform light emission characteristics in each part on the coated material, and as a result, injected charges are injected. The light emission based on is uniformly generated in the plane, and the light emission efficiency is improved.
The complex of the present invention has higher efficiency than conventional coating type light emitting / phosphorescent materials and can suppress aggregation of the light emitting material itself, so that it can be driven at a low voltage. In addition, the organic compound of the present invention has high thermal stability and is advantageous in improving the life.

Therefore, the complex of the present invention solves various problems of the conventional coating type light emitting / phosphorescent materials and enables realization of a long-life organic EL device by high efficiency light emission.
Since the organic EL device according to the present invention is provided with a layer containing the complex of the present invention having the above-described effects, a layer having a high dispersibility of the material can be easily obtained by coating as compared with the prior art, and further higher. Luminous efficiency can be obtained and a long-life element can be realized.

Hereinafter, the iridium complex of the present invention will be described in detail.
The iridium complex according to the present invention is a compound represented by the following general formula (1).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom, an alkyl group, a halogen atom, an alkoxy group, a halogenated alkyl group, A dialkylamino group and a diarylamino group, each R group may be bonded to another R group, and R ⁹ and R ¹⁰ are each independently an alkyl group, an aryl group, an alkoxy group or a halogenated group. Represents an alkyl group, R ¹¹ represents a hydrogen atom, an alkyl group, an aryl group or a halogenated alkyl group, and R ⁹ , R ¹⁰ and R ¹¹ represent a polymerizable group or a group obtained by polymerizing the polymerizable group. Provided that at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ has 5 or more carbon atoms. Alkyl, aralkyl or alkyl .n representing the alkoxy group represents an integer of 1 or 2, n1 is an integer of 1 or 2, the sum of n and n1 is 3.)

Hereinafter, in the general formula (1), the groups represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ will be described.
Examples of the alkyl group include a linear or branched alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and 3 to 30 carbon atoms. A monocyclic, polycyclic, or bridged cycloalkyl group, preferably having 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms. Specific examples include, for example, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, 2-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, 2-ethylhexyl group, n-heptyl group, n-octyl group N-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, Such as Kurohekishiru group, and the like.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.

  Examples of the alkoxy group include a group in which an oxygen atom is bonded to the alkyl group as described above, and specific examples include, for example, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a tert group. -Butoxy group, n-hexyloxy group, 2-ethylhexyloxy group, n-heptyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group And cyclohexyloxy group.

  Examples of the halogenated alkyl group include groups in which one or more hydrogen atoms of the alkyl group described above are halogen-substituted by a halogen atom such as a fluorine atom or a chlorine atom. Specifically, for example, a trifluoromethyl group, And perfluoroalkyl groups such as a pentafluoroethyl group.

  Examples of the dialkylamino group include those in which two hydrogen atoms of the amino group are each independently substituted with an alkyl group as described above. Specific examples include, for example, a dimethylamino group, a diethylamino group, a dialkyl group, and the like. Examples include (n-propyl) amino group, diisopropylamino group, di (n-butyl) amino group, di (n-hexyl) amino group, dicyclohexylamino group and the like.

  Examples of the aryl group include monocyclic, polycyclic, or condensed cyclic aryl groups having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, and more preferably 6 to 12 carbon atoms. Examples thereof include a phenyl group, a tolyl group, a naphthyl group, and an anthranyl group. These aryl groups may have a substituent such as an alkyl group, an alkoxy group, a halogenated alkyl group, or a halogen atom.

  Examples of the diarylamino group include those in which two hydrogen atoms of the amino group are each independently substituted with the above-mentioned aryl group. Specific examples include, for example, a diphenylamino group, a ditolylamino group, a phenylnaphthylamino group. Groups and the like.

  Examples of the aralkyl group include a group in which at least one hydrogen atom of the alkyl group is substituted with the aryl group, and specifically includes a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group, a 1-phenylpropoxy group. Group, 3-naphthylpropyl group and the like.

Further, R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁶ and R ⁷ and R ⁷ and R ⁸ are adjacent to each other, or R ⁴ and R ⁵ When the groups positioned in the ortho positions to each other form a ring together with adjacent carbon atoms, the formed ring may be a saturated or unsaturated monocyclic or polycyclic ring, and may be a 5-membered ring. Or a 6-membered ring is preferable. Similarly, when R ⁹ and R ¹¹ or R ¹⁰ and R ¹¹ together form a ring with adjacent carbon atoms, the ring formed may be a saturated or unsaturated monocyclic or polycyclic ring. Well, a 5-membered ring or a 6-membered ring is preferable. Preferable rings thus formed include carbocyclic aromatic rings such as benzene ring and naphthalene ring, aromatic heterocyclic rings such as pyridine ring and pyrazine ring, and the like.

Hereinafter, specific structural formulas of the highly soluble iridium metal complex of the present invention are shown below. However, the present invention is not limited to merely representative examples. In the compounds, Ph represents a phenyl group, and Cy represents a cyclohexyl group.

  These iridium complexes of the present invention can be used as materials for organic electroluminescence elements (organic EL elements) by themselves. Preferably, these iridium complexes of the present invention can be used as a host material for an organic EL device.

  Next, the manufacturing method of the iridium complex of this invention is demonstrated in detail. The compound represented by the general formula (1) of the present invention can be synthesized by various methods, for example, Inorg. Chem. 1991, 30, 1685, 1988, 27, 3464. 1994, 33, 545, Inorg. Chem. Acta 1991, 181, 245, J. Organomet. Chem. 1987, 335, 293, J. Am. Chem. Soc. 1985, 107, page 1431 and the like can be synthesized by a known method. That is, various ligands or their free forms and an iridium compound are reacted with a base in the presence of a solvent (for example, a halogen solvent, an alcohol solvent, an ether solvent, water, etc.) or in the absence of a solvent. In the presence (including various inorganic and organic bases such as sodium methoxide, t-butoxypotassium, triethylamine, potassium carbonate, etc.) or in the absence of a base or below room temperature or heated (in addition to normal heating) A technique of heating with a microwave is also effective) and can be synthesized.

  Examples of the iridium compound as the starting material include (1,5-cyclooctadiene) iridium (I) chloride dimer, iridium chloride (III) hydrate, hexahalogenated iridium (III) compound such as potassium hexachloroiridium. Date (III), iridium (IV) halide compounds such as potassium hexachloroiridate (IV) and analogs thereof can be used.

  A trivalent hexacoordinate orthometalated iridium binuclear complex was synthesized from a stoichiometric amount of the ligand and the above iridium compound, and then the ligand was reacted in the presence or absence of a base. The compound of 1) is synthesized. If necessary, silver trifluoromethanesulfonate may be used.

  Examples of the solvent include amides such as N, N-dimethylformamide, formamide, N, N-dimethylacetamide, nitriles such as acetonitrile, dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, o-dichlorobenzene. Halogenated hydrocarbons such as, pentane, hexane, heptane, octane, decane and other aliphatic hydrocarbons, benzene, toluene, xylene and other aromatic hydrocarbons, diethyl ether, diisopropyl ether, tert-butyl methyl ether, Ethers such as 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, ketones such as acetone and methyl ethyl ketone, methanol, ethanol, 2-propanol, n-butanol, tert-butanol, - alcohols such as ethoxyethanol, ethylene glycol, propylene glycol, 1,2-propane diol, polyhydric alcohols such as glycerin, water and the like. These solvents may be used alone or in combination of two or more. These solvents include alcohols such as methanol, ethanol, 2-propanol, n-butanol, tert-butanol, 2-ethoxyethanol, polyhydric alcohols such as ethylene glycol, propylene glycol, 1,2-propanediol, glycerin, and the like. It is preferable to use water alone or in combination of two or more.

  The amount of the solvent to be used is not particularly limited as long as the reaction can proceed sufficiently, but it is preferably about 1 to 200 times, preferably about 5 to 50 times the amount of the iridium starting material. .

  This reaction is preferably performed in an inert gas atmosphere. Examples of the inert gas include nitrogen gas and argon gas. Moreover, the said manufacturing method can be performed using an ultrasonic generator together.

The reaction temperature is usually appropriately selected from the range of 25 ° C to 300 ° C, preferably 60 ° C to 200 ° C, more preferably 80 ° C to 150 ° C.
The reaction time is appropriately selected from the range of usually 10 minutes to 72 hours, preferably 30 minutes to 48 hours, more preferably 1 hour to 6 hours.

  This production method is preferably carried out in the presence of a base. Examples of the base include inorganic bases and organic bases. Examples of the inorganic base include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and the like. Examples of the organic base include alkali metal alkoxides such as potassium methoxide, sodium methoxide, lithium methoxide, sodium ethoxide, potassium tert-butoxide, triethylamine, diisopropylethylamine, N, N-dimethylaniline, piperidine, pyridine, 4 -Dimethylaminopyridine, 1,5-diazabicyclo [4.3.0] non-5-ene, 1,8-diazabicyclo [5.4.0] undec-7-ene, tri-n-butylamine, N-methyl Examples thereof include organic amines such as morpholine and metal hydrides such as sodium hydride.

The amount of the base used is appropriately selected from the range of usually 0.5 to 10 equivalents, preferably 0.8 to 2 equivalents, more preferably 1 to 1.2 equivalents, relative to the compound represented by the general formula (1). Is done.
Moreover, you may react by adding silver salt. Examples of the silver salt include silver nitrate, silver acetate, silver trifluoroacetate, silver methanesulfonate, silver trifluoromethanesulfonate, and the like, among which silver trifluoroacetate and silver trifluoromethanesulfonate are preferable. The usage-amount of silver salt is normally selected suitably from the range of 1-20 equivalent with respect to the compound represented by General formula (1), Preferably it is 1.5-10 equivalent, More preferably, it is 2-3 equivalent.

  This reaction can be performed in multiple stages by post-treatment, isolation and purification as necessary, or can be carried out in one pot without any post-treatment. Examples of the post-treatment method include extraction of reactants, filtration of precipitates, crystallization by addition of a solvent, and evaporation of the solvent, and these can be performed alone or in combination. Examples of the purification method include column chromatography, recrystallization, sublimation and the like, and these can be performed alone or in combination.

The well-soluble iridium complex of the present invention includes a Hildebrand solubility parameter (δ = (E / V) ^1/2 in each solvent, where E represents the molar cohesive energy, and V represents the volume of the molecule. The solubility parameter δ is preferably 0.1% by weight or more in a solvent having a solubility parameter δ in the range of 6 to 11, preferably 7 to 10. Specific solvents include aliphatic hydrocarbons such as pentane, hexane, octane, cyclopentane and cyclohexane, ethers such as ethyl ether, propyl ether, methyl tert-butyl ether, cyclopentyl methyl ether and tetrahydrofuran, benzene, toluene and xylene. , Aromatic hydrocarbons such as mesitylene, ethylbenzene, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, acetophenone, halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane, esters such as ethyl acetate, etc. Is mentioned.

  The method for forming the organic layer (organic compound layer) of the light-emitting element is not particularly limited, but methods such as sputtering, molecular lamination, coating, and inkjet are preferable. More preferably, an organic solvent solution such as a constituent material is prepared, and printing or coating is performed by a coating method such as spray coating, spin coating or dip coating, a printing method such as gravure printing, flexographic printing or screen printing, or an ink jet method. And dry to form a film. There is no particular limitation on the drying method. Moreover, in order to adjust the viscosity of various materials, a polymer material may be included. The polymer material mixed at this time preferably has a charge or hole transport layer so as not to deteriorate the performance of the device. Examples thereof include polyphenylene, polyfluorene, polythiophene, polyphenylene vinylene, polyvinyl carbazole, polypyrrole, polyacetylene, polyaniline, polyoxadiazole and the like that are soluble in a solvent. Particularly preferred are polyparaphenylene and polyvinylcarbazole which are soluble in a solvent. It is also a preferred embodiment to add a material that assists electron transport. Specific examples of such materials that assist electron transport include, for example, triazole derivatives, oxazole derivatives, polycyclic compounds, heteropolycyclic compounds such as bathocuproine, oxadiazole derivatives, fluorenone derivatives, diphenylquinone derivatives, Thiopyran dioxide derivatives, anthraquinone dimethane derivatives, anthrone derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, acid anhydrides of aromatic ring tetracarboxylic acids such as naphthalenetetracarboxylic acid or perylenetetracarboxylic acid, phthalocyanines Derivatives, metal complexes of 8-quinolinol derivatives, metal phthalocyanines, various metal complexes represented by metal complexes having benzoxazole or benzothiazole as a ligand, organosilane derivatives, iridium complexes, etc. And the like.

  When the iridium complex of the present invention is used as the host material of the light emitting layer, the mixing ratio of the host material and the guest material in the light emitting layer is such that the concentration of the guest material in the light emitting layer is at least 0.5% or more. Specifically, the range of 0.5: 99.5 to 99.5: 0.5 is preferable. The thickness of the light-emitting layer is not particularly limited, but it is preferable that the light-emitting layer be formed so as to have a high light emission efficiency and be 10 nm to 500 nm when dried to 1 nm to 1 μm.

  As the organic solvent, any organic solvent can be used as long as the material can be dissolved. For example, cyclohexanone, toluene, xylene, tetrahydrofuran, chloroform, dichloromethane, 1,1,2-trichloroethane, chlorobenzene, o-dichlorobenzene, tetralin, 1,1,2,2-tetrachloroethane, butyl carbitol, N-methylpyrrolidone, Examples include acetic acid, methanol, ethanol, phenol, butanol, water, and the like. When the volatilization rate of the solvent is high, the viscosity of the solution is increased and the material is easily fixed to the printing plate to be used. Therefore, the vapor pressure at 25 ° C. is about 16 to 350 Pa (0.12 to 2.5 mmHg). It is preferable that the boiling point is within the range of 100 to 300 ° C. at normal pressure. Examples of such solvents are toluene, xylene, cyclohexanone, chlorobenzene, o-dichlorobenzene, tetralin, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, butyl carbitol, N-methylpyrrolidone. , Acetic acid, phenol, butanol, water and the like. These solvents may be used alone or in combination.

  The concentration of the guest and host compound solution varies depending on the printing method and the coating method, but is preferably in the range of 0.1% by mass to 15% by mass. If the concentration of the guest and host compound is less than 0.1% by mass, the film thickness after drying after printing or coating may become too thin, which may cause a short circuit of the organic EL device. On the other hand, if the concentration of the guest and host compounds exceeds 15% by mass, the printed or coated film thickness after drying increases, and the voltage required for light emission increases or the light emission luminance decreases. From the performance of the obtained organic EL device, the concentration of the material in the solution is particularly preferably in the range of 0.5% by mass to 10% by mass. If the concentration of the material in the solution is within this range, the thickness of the light emitting layer after drying can be easily controlled to be 1 nm to 1 μm.

  When providing different layers, such as an electron carrying layer, on the said light emitting layer, it provides on the said light emitting layer by the wet film forming method or the vacuum evaporation method. A wet film forming method such as an ink jet method, a printing method or a coating method is preferable. A solution obtained by dissolving or dispersing a material in a solvent by a wet film forming method is applied and dried by a known coating method, ink jet method, printing method or the like. There is no particular limitation on the drying method. The solvent used at this time is preferably a solvent that does not dissolve the light emitting layer. At this time, when the compound concentration in the solvent is adjusted to be 0.1 to 10% by mass, the thickness of the electron transport layer after drying is easily controlled to be 1 nm to 200 nm.

  A light emitting element is an element in which a plurality of organic compound thin films including a light emitting layer or a light emitting layer are formed between a pair of electrodes of an anode and a cathode. In addition to a light emitting layer, a hole injection layer, a hole transport layer, an electron injection layer, An electron transport layer, a protective layer, and the like may be provided, and each of these layers may have a different function. Various materials can be used for forming each layer.

  The anode supplies holes to a hole injection layer, a hole transport layer, a light emitting layer, and the like, and a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. Is a material having a work function of 4 eV or more. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, and indium tin oxide (hereinafter referred to as ITO), metals such as gold, silver, chromium, and nickel, and conductivity with these metals. Examples include mixtures or laminates with metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO. In particular, ITO is preferable in terms of productivity, high conductivity, transparency, and the like. The thickness of the anode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, and further preferably 100 nm to 500 nm.

  As the anode, a layer formed on a soda-lime glass, non-alkali glass, a transparent resin substrate or the like is usually used. When glass is used, it is preferable to use non-alkali glass as the material in order to reduce ions eluted from the glass. Moreover, when using soda-lime glass, it is preferable to use what gave barrier coatings, such as a silica. The thickness of the substrate is not particularly limited as long as it is sufficient to maintain the mechanical strength, but when glass is used, a thickness of 0.2 mm or more, preferably 0.7 mm or more is usually used. Various methods are used for producing the anode depending on the material. For example, in the case of ITO, an electron beam method, a sputtering method, a resistance heating vapor deposition method, a chemical reaction method (sol-gel method, etc.), an ITO dispersion coating, etc. A film is formed by the method. The anode can be subjected to cleaning and other treatments to lower the drive voltage of the element and increase the light emission efficiency. For example, in the case of ITO, UV-ozone treatment, plasma treatment, etc. are effective.

  The cathode supplies electrons to the electron injection layer, the electron transport layer, the light emitting layer, etc., and the adhesion, ionization potential, stability, etc., between the negative electrode and the adjacent layer such as the electron injection layer, electron transport layer, light emitting layer, etc. Selected in consideration of As the material of the cathode, metals, alloys, metal halides, metal oxides, electrically conductive compounds, or mixtures thereof can be used. Specific examples include alkali metals such as lithium, sodium and potassium and fluorides thereof, magnesium. Alkaline earth metals such as calcium and fluorides thereof, gold, silver, lead, aluminum, sodium-potassium alloys or mixed metals thereof, magnesium-silver alloys or mixed metals thereof, rare earth metals such as indium and ytterbium, etc. Preferably, the material has a work function of 4 eV or less, more preferably aluminum, a lithium-aluminum alloy or a mixed metal thereof, a magnesium-silver alloy or a mixed metal thereof.

The cathode can also have a laminated structure containing the above compound and mixture. The thickness of the cathode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, and further preferably 100 nm to 1 μm. For production of the cathode, methods such as an electron beam method, a sputtering method, a resistance heating vapor deposition method, and a coating method are used, and a metal can be vapor-deposited alone or two or more components can be vapor-deposited simultaneously. Furthermore, it is possible to form a pole with an alloy by simultaneously depositing a plurality of metals, or an alloy prepared in advance may be deposited. The sheet resistance of the cathode and the anode is preferably low.
The light emitting layer usually preferably has a range of 1 nm to 5 μm, more preferably 5 nm to 1 μm, and still more preferably 10 nm to 500 nm. The method for producing the light emitting layer is not particularly limited, but an electron beam method, a sputtering method, a resistance heating vapor deposition method, a molecular lamination method, a coating method (spin coating method, casting method, dip coating method, etc.), an ink jet method. , LB method or the like is used, preferably resistance heating vapor deposition or coating method.

  The material of the hole injection layer and the hole transport layer has any one of the function of injecting holes from the anode, the function of transporting holes, and the function of blocking electrons injected from the cathode. It ’s fine. Specific examples include carbazole derivatives, triazole derivatives, oxadiazole derivatives, oxazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, Fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole) derivatives, aniline derivatives Examples thereof include polymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, organosilane derivatives, iridium complexes, and the like. The thicknesses of the hole injection layer and the hole transport layer are not particularly limited, but are usually preferably in the range of 1 nm to 5 μm, more preferably 5 nm to 1 μm, and still more preferably 10 nm to 500 nm. The hole injection layer and the hole transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. The hole injection layer and the hole transport layer can be prepared by a vacuum deposition method, an LB method, a method in which the above hole injection / transport agent is dissolved or dispersed in a solvent (a spin coating method, a casting method, a dip coating method). Etc.), a method such as an inkjet method is used. In the case of the coating method, it can be dissolved or dispersed together with the resin component. Examples of the resin component include polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, and poly (N -Vinyl carbazole), hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, vinyl acetate, ABS resin, alkyd resin, epoxy resin, silicon resin, and the like.

  The material of the electron injection layer and the electron transport layer may be any material having any one of the function of injecting electrons from the cathode, the function of transporting electrons, and the function of blocking holes injected from the anode. The ionization potential of the hole blocking layer having a function of blocking holes injected from the anode is selected to be larger than the ionization potential of the light emitting layer.

  Specific examples include triazole derivatives, oxazole derivatives, polycyclic compounds, heteropolycyclic compounds such as bathocuproine, oxadiazole derivatives, fluorenone derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, anthraquinone dimethane derivatives, anthrone derivatives. Carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, acid anhydrides of aromatic ring tetracarboxylic acids such as naphthalenetetracarboxylic acid or perylenetetracarboxylic acid, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives and metal phthalocyanines, Examples include various metal complexes represented by metal complexes having benzoxazole or benzothiazole as a ligand, organic silane derivatives, iridium complexes, and the like. Although the film thickness of an electron injection layer and an electron carrying layer is not specifically limited, Usually, the range of 1 nm-5 micrometers is preferable, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm. The electron injection layer and the electron transport layer may have a single-layer structure made of one or more of the materials described above, or may have a multilayer structure made up of a plurality of layers having the same composition or different compositions. As a method for forming the electron injection layer and the electron transport layer, a vacuum deposition method, an LB method, a method in which the hole injection / transport agent is dissolved or dispersed in a solvent (a spin coating method, a casting method, a dip coating method, etc.) ), An ink jet method or the like is used. In the case of the coating method, it can be dissolved or dispersed together with the resin component. As the resin component, those exemplified in the case of the hole injection layer and the hole transport layer can be applied.

  As a material for the protective layer, any material may be used as long as it has a function of suppressing the entry of elements that promote element deterioration such as moisture and oxygen into the element. Specific examples include metals such as indium, tin, lead, gold, silver, copper, aluminum, titanium, nickel, magnesium oxide, silicon oxide, aluminum oxide, germanium oxide, nickel oxide, calcium oxide, barium oxide, iron oxide, Metal oxides such as ytterbium oxide, titanium oxide, magnesium fluoride, lithium fluoride, aluminum fluoride, calcium fluoride metal fluoride, polyethylene, polypropylene, polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychloro Copolymers obtained by copolymerizing trifluoroethylene, polydichlorodifluoroethylene, copolymers of chlorotrifluoroethylene and dichlorodifluoroethylene, and monomer mixtures containing tetrafluoroethylene and at least one comonomer. Coalesced, copolymerization main chain fluorine-containing copolymer having a cyclic structure, 1% by weight of the water absorbing material water absorption, water absorption of 0.1% or less of the moisture-proof material, and the like. There is no particular limitation on the method for forming the protective layer. For example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency excitation ions) Plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method can be applied.

  The high-efficiency light-emitting element obtained in this way can be applied to products that require energy saving and high luminance. Application examples include light sources for display devices / illuminators and printers, backlights for liquid crystal display devices, and the like. As a display device, energy-saving, high visibility and lightweight flat panel display can be realized. Further, as the light source of the printer, the laser light source part of the laser beam printer that is currently widely used can be replaced with the light emitting element obtained as described above. Elements that can be independently addressed are arranged on the array, and an image is formed by performing desired exposure on the photosensitive drum. By using such an element, the volume of the apparatus can be greatly reduced. In application to a display, a driving method using a TFT driving circuit which is a simple matrix method or an active matrix method can be considered. A multilayer or single-layer organic EL layer / cathode layer is sequentially laminated on the ITO electrode to obtain an organic EL display panel.

  EXAMPLES The present invention will be specifically described below with reference to examples and the like, but the present invention is not limited to these.

Example 1
Production of compound (1-1) (bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) 2,4-tridecanedionate),
Compound (1-1) was produced according to the reaction formula shown below.

Under a nitrogen atmosphere, a (1,5-cyclooctadiene) iridium (I) chloride dimer (5.0 g, 7.44 mmol, 1 equivalent) was placed in a Schlenk flask equipped with a reflux tube, and 2-ethoxyethanol ( 50 mL) and 2-phenylpyridine (4.852 g, 3.13 mmol, 4.2 equivalents) were sequentially added and stirred at 135 ° C. for 3 hours. The resulting yellow suspension was cooled to room temperature, yielding the intermediate bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) chloride dimer as a suspension. To this suspension, 2,4-tridecanedione (4.76 g, 22.3 mmol, 3.0 eq) and sodium carbonate (2.37 g, 22.3 mmol, 3.0 eq) were added sequentially, and 135 ° C. The mixture was further stirred for 2 hours to obtain a bright yellow suspension. The solvent was distilled off from the reaction solution under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane). The column fraction was concentrated and recrystallized from hexane / dichloromethane to obtain 4.77 g of the title compound (1-1) as a bright yellow powder. Yield 89.9%. Further, sublimation purification was performed under reduced pressure.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ 0.89 (t, J = 7.2 Hz, 3H), 0.91-1.38 (m, 14H), 1.97 (t, J = 7.4 Hz, 2H), 5.19 (s, 1H)
MS (C ₃₅ H ₃₉ N ₂ O ₂ Ir: MW712.26): Found: 712.0, 501.1

(Example 2)
Production of compound (1-2) (bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) 10,12-henicosandionate),
Compound (1-2) was produced according to the reaction formula shown below.

A bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) chloride dimer (1.5 g, 1. g) obtained in the same manner as in Example 1 in a Schlenk flask equipped with a reflux tube under a nitrogen atmosphere. 4 mmol, 1 equivalent) was taken, and 1-butanol (30 mL) and 10,12-henicosandione (1.2 g, 3.68 mmol, 1.3 equivalent) were sequentially added thereto. Further, sodium tertiary butoxide (0.37 g, 3.12 mmol, 1.1 equivalents) was gradually added, and the mixture was stirred at 135 ° C. for 3 hours. The resulting yellow suspension was cooled to room temperature, filtered, and the filtrate was purified by silica gel column chromatography (eluent: toluene). The column fraction was concentrated and recrystallized from heptane to obtain 0.743 g (0.90 mmol) of the title compound (1-2) as a bright yellow powder. Yield 32.0%.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ0.88 (t, J = 7.3Hz, 6H), 0.95-1.35 (m, 28H), 1.99 (td, 4H), 5.18 (s, 1H), 6.32 (d, J = 7.6Hz, 2H), 6.68 (dd, J = 7.6, 7.7Hz, 2H), 6.81 (dd, J = 7.6, 7.7Hz, 2H), 7.08 (dd, J = 5.8, 8.1Hz , 2H), 7.55 (d, J = 7.7Hz, 2H), 7.70 (dd, J = 5.8, 8.1Hz, 2H), 7.83 (d, J = 8.1Hz, 2H), 8.49 (d, J = 5.8Hz , 2H)
MS (C ₄₃ H ₅₅ N ₂ O ₂ Ir: MW824.22): Actual value: 824.3, 501.2

(Example 3)
Production of compound (1-3) (bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) 3-dodecyl-2.4-pentanedionate),
Compound (1-3) was produced according to the following reaction formula.

Under a nitrogen atmosphere, a (1,5-cyclooctadiene) iridium (I) chloride dimer (2.0 g, 2.98 mmol, 1 equivalent) was placed in a Schlenk flask equipped with a reflux tube, and 2-ethoxyethanol ( 30 mL) and 2-phenylpyridine (1.85 g, 11.9 mmol, 2 equivalents) were sequentially added, and the mixture was stirred at 135 ° C. for 3 hours. After cooling the resulting yellow suspension to room temperature, 3-dodecyl-2.4-pentadione (2.04 g, 7.74 mmol, 1.3 eq) was added, followed by sodium tertiary butoxide (0.601 g). , 6.25 mmol, 1.05 eq.) Was gradually added, followed by stirring at room temperature for 10 hours. The resulting yellow suspension was cooled to room temperature and then filtered, the filtrate was dissolved in toluene, and the toluene solution was washed with water. Further, after washing twice with a saturated saline solution, the solvent was distilled off. The obtained crude product was recrystallized from methylene chloride / heptane to obtain 3.23 g (5.26 mmol) of compound (1-3) as a bright yellow powder. Yield 88.3%.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ 0.88 (t, J = 7.1Hz, 3H), 1.20-1.31 (m, 20H), 1.57 (d, J = 7.0Hz, 2H), 2.01 (s, 3H), 2.33 (s, 3H), 6.08 (d, J = 7.8Hz, 2H), 6.63 (dd, J = 7.5Hz, 7.8Hz, 2H), 6.78 (dd, J = 7.5Hz, 7.8Hz, 2H ), 7.27 (dd, J = 8.0Hz, 5.5Hz, 2H), 7.51 (d, J = 7.8Hz, 2H), 7.80 (dd, J = 8.0Hz, 5.5Hz, 2H), 7.87 (d, J = 8.0Hz, 2H), 8.87 (d, J = 5.5Hz, 2H)
MS (C ₃₉ H ₄₇ N ₂ O ₂ Ir: MW768.32); Found: 768.2, 501.2

Example 4
Preparation of compound (1-4) (bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) dodecyl-3-oxobutanoate)
Compound (1-4) was produced according to the following reaction formula.

Under a nitrogen atmosphere, bis (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) chloride dimer (1.83 g, 1.71 mmol, 1 equivalent) was placed in a Schlenk flask equipped with a reflux tube. 100 ml of acetone was added to the solution. Further, silver trifluoromethanesulfonate (1.756 g, 6.83 mmol, 2 equivalents) was added and stirred under reflux for 3 hours. After cooling to room temperature, the precipitated silver chloride was filtered. The obtained filtrate was added to a Schlenk flask equipped with a reflux tube under nitrogen, and dodecyl-3-oxobutanoate (2.3409 g, 8.72 mmol, 2.55 eq) and 1.5 mL of triethylamine were further added. The mixture was stirred for 5 hours under reflux and then cooled to room temperature. After the reaction solution was filtered, the filtrate was distilled off under reduced pressure. The obtained crude product was dissolved in methylene chloride, filtered through Celite, the solvent was distilled off from the filtrate, and heptane recrystallization was repeated three times to obtain the compound (1-4) as a bright yellow powder. Obtained 602 g (0.784 mmol). Yield 22.9%.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ 0.89 (t, J = 7.1 Hz, 3H), 1.01-1.36 (m, 16H), 3.08 (s, 3H), 3.76 (m, 2H), 4.69 ( s, 1H), 6.23 (d, J = 7.6Hz, 1H), 6.27 (d, J = 7.6Hz, 1H), 6.67 (m, 2H), 6.79 (m, 2H), 7.13 (m, 2H), 7.52 (d, J = 7.8Hz, 2H), 7.54 (d, J = 7.54, 2H), 7.72 (dd, 2H), 7.82 (d, J = 8.0Hz, 1H), 7.82 (d, J = 8.0Hz , 1H), 8.54 (d, J = 7.7Hz, 1H), 8.62 (d, J = 7.7Hz, 1H)
MS (C ₃₈ H ₄₅ N ₂ O ₂ Ir: MW770.30): Actual value: 770.0, 501.1, 154.0

(Example 5)
Preparation of compound (1-5) (bis (2- (4-decylphenyl) pyridinato-N, C ^{2 ′} ) iridium (III) acetylacetonate),
Compound (1-5) was produced according to the reaction formula shown below.

Under a nitrogen atmosphere, a (1,5-cyclooctadiene) iridium (I) chloride dimer (0.5 g, 0.744 mmol, 1 equivalent) was placed in a Schlenk flask equipped with a reflux tube, and 2-ethoxyethanol ( 30 mL) and 2- (4-decylphenyl) pyridine (0.88 g, purity 90%, 5.10 mmol, 3.4 equivalents) were sequentially added, and the mixture was stirred at 135 ° C. for 4 hours. After cooling the obtained yellow suspension to room temperature, potassium acetylacetonate hydrate (0.29 g, purity 97%, 1.91 mmol, 2.6 equivalents) was added, and the mixture was further refluxed for 2 hours. Stirring to obtain a bright yellow suspension. The solvent was distilled off from the reaction solution under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane). The column fraction was concentrated and recrystallized from heptane / dichloromethane to obtain 0.5154 g (0.585 mmol) of the title compound (1-5) as a bright yellow powder. Yield 39.3%.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ0.883 (t, J = 7.1Hz, 6H), 1.04-1.42 (m, 32H), 1.77 (s, 6H), 2.27 (d, J = 7.7Hz , 4H), 5.19 (s, 1H), 6.02 (s, 2H), 6.61 (d, J = 7.9Hz, 2H), 7.08 (dd, J = 5.7, 8.0Hz, 2H), 7.43 (d, J = 8.0Hz, 2H), 7.68 (dd, J = 5.7, 8.0Hz, 2H), 7.79 (d, J = 8.0Hz, 2H), 8.48 (d, J = 5.7Hz, 2H)
MS (C ₄₇ H ₆₃ N ₂ O ₂ Ir: MW880.45): Found: 880.2, 781.3

(Example 6)
Preparation of Compound (1-6) (Bis (2- (3-hexylphenyl) pyridinato-N, C ^{2 ′} ) iridium (III) acetylacetonate) Compound (1-6) was prepared according to the following reaction formula .

Under a nitrogen atmosphere, a (1,5-cyclooctadiene) iridium (I) chloride dimer (1.0 g, 1.44 mmol, 1 equivalent) was placed in a Schlenk flask equipped with a reflux tube, and 2-ethoxyethanol ( 60 mL) and 2- (3-hexylphenyl) pyridine (1.425 g, 5.95 mmol, 2 equivalents) were sequentially added, and the mixture was stirred at 135 ° C. for 4 hours. After cooling the obtained yellow suspension to room temperature, potassium acetylacetonate hydrate (0.57 g, purity 97%, 3.76 mmol, 1.3 eq) was added, and the mixture was further refluxed for 2 hours. Stirring to obtain a bright yellow suspension. The solvent was distilled off from the reaction solution under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: dichloromethane). The column fraction was concentrated and recrystallized from heptane / dichloromethane to obtain 0.8898 g (1.16 mmol) of the title compound (1-6) as a bright yellow powder. Yield 38.9%.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ 0.86 (t, J = 7.1Hz, 6H), 1.21-1.32 (m, 12H), 1.51-1.58 (m, 4H), 2.43 (t, J = 7.7 Hz, 4H), 5.19 (s, 1H), 6.16 (d, J = 7.8Hz, 2H), 6.54 (d, J = 7.8Hz, 2H), 7.09 (dd, J = 8.1Hz, 6.3Hz, 2H) , 7.35 (s, 1H), 7.69 (dd, J = 8.1Hz, 6.3Hz, 2H), 7.83 (d, J = 8.1Hz, 2H), 8.59 (d, J = 6.3Hz, 2H)
MS (C ₃₉ H ₄₇ N ₂ O ₂ Ir: 768.32): Actual measurement: 768.0, 669.1

(Example 7)
Preparation of compound (1-7) (bis (2-phenyl (4-pentyl-pyridinato) -N, C ^{2 ′} ) iridium (III) 2,4-pentadionate)
Compound (1-7) was produced according to the reaction formula shown below.

Under a nitrogen atmosphere, a (1,5-cyclooctadiene) iridium (I) chloride dimer (0.2 g, 0.298 mmol, 1 equivalent) was placed in a Schlenk flask equipped with a reflux tube, and 2-ethoxyethanol ( 25 mL) and 2-phenyl-4-pentylpyridine (0.352 g, 1.07 mmol, 3.6 equivalents) were sequentially added, and the mixture was stirred at 135 ° C. for 4 hours. After cooling the obtained yellow suspension to room temperature, potassium acetylacetonate hydrate (0.152 g, purity 97%, 1.07 mmol, 3.4 equivalents) was added, and the mixture was further refluxed for 2 hours. Stirring to obtain a bright yellow suspension. The solvent was distilled off from the reaction solution under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: toluene / ethyl acetate). The column fraction was concentrated and recrystallized from toluene / heptane to obtain 0.216 g (0.29 mmol) of the title compound (1-7) as a bright yellow powder. Yield 49.1%.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ 0.95 (t, J = 7.1 Hz, 6H), 1.42 (m, 8H), 1.77 (m, 4H), 1.78 (s, 6H), 2.80 (t, J = 7.9Hz, 4H), 5.19 (s, 1H), 6.25 (d, J = 7.6Hz, 2H), 6.66 (dd, J = 7.6Hz, 7.8Hz, 2H), 6.78 (dd, J = 7.6Hz , 7.8Hz, 2H), 6.97 (d, J = 5.9Hz, 2H), 7.52 (d, J = 7.8Hz, 2H), 7.64 (s, 2H), 8.36 (d, J = 5.9Hz, 2H)
_{MS (C 37 H 48 N 2} O 2 Ir: 740.04): Found: 741.4, 692.3, 673.4, 641.4

(Synthesis Example 1)
Synthesis of compound (2-1)

  Under an argon atmosphere, N, N-bis [3- (2-pyridyl) phenyl] -3,5-di (t-butyl) aniline (248 mg) and potassium tetrachloroplatinate (II) (306 mg) were mixed, Acetic acid was added and stirred at 140 ° C. for 3 days. After the addition of water, extraction with methylene chloride was performed, the solvent was distilled off, and the residue was purified by silica gel column chromatography to obtain compound (2-1) as red crystals (124 mg).

(Synthesis Example 2)
Synthesis of compound (2-2)

  Platinum (II) chloride (212 mg) and N, N-bis [3- (2-pyridyl) phenyl] -4-n-octylaniline (409 mg) were added to benzonitrile, and the mixture was stirred under reflux for 5 hours. . After allowing to cool, benzonitrile was distilled off, followed by addition of water and extraction with methylene chloride. The extract was concentrated to remove methylene chloride, and the resulting residue was purified by silica gel column chromatography to obtain compound (2-2) as red crystals (328 mg).

(Element Example 1)
An organic EL element having the structure of the element structure 1 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. PEDT represents poly (3,4-ethylenedioxythiophene), and PSS represents polysulfostyrene (hereinafter the same). Furthermore, as a light emitting layer, the compound (1-1) produced in Example 1 as a host material, the compound (2-1) produced in Synthesis Example 1 as a guest material, and the following formula

A compound dissolved in 1,2-dichloroethane (host: OXD-7: guest = 47: 47: 6 (= mass ratio)) was prepared as an electron transporting material using the compound OXD-7 represented by formula It was applied with. On top of this, 30 nm of Ba and then 100 nm of Al were deposited as a back electrode. When current was passed through the device, it emitted red light at 6.8V. The measured characteristics of the device are shown in Table 1.

(Element Example 2)
An organic EL element having the structure of the element structure 3 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. Furthermore, as a light emitting layer, the compound (1-1) produced in Example 1 was used as a host material, and the compound (2-1) produced in Synthesis Example 1 was used as a guest material, and 1,2-dichloroethane (Host: guest = 94: 6 (= mass ratio)) was prepared and applied at 80 nm by spin coating. Next, batocuproine (BCP: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) was deposited to a thickness of 100 nm as a hole blocking layer. Next, an aluminum-oxine complex (Alq) is deposited at 200 nm by vapor deposition as an electron transport layer. On top of that, LiF was vapor-deposited at 0.5 nm and then Al at 100 nm as a back electrode. When current was passed through the device, it emitted red light at 5.3V. The measured characteristics of the device are shown in Table 1.

(Element Example 3)
An organic EL element having the structure of the element structure 3 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. Further, as the light emitting layer, the compound (1-1) produced in Example 1 was used as a host material, OXD-7 was used as an electron transport material, and the compound (2-1) produced in Synthesis Example 2 was further used. Was dissolved in 1,2-dichloroethane (host: OXD-7: guest = 47: 47: 6 (= mass ratio)) and applied at 80 nm by spin coating. Next, as a hole blocking layer, BCP was deposited at 100 nm by deposition. Next, an electron transport layer is formed at a thickness of 200 nm by aluminum-oxine complex (Alq) deposition. On top of that, LiF was vapor-deposited at 0.5 nm and then Al at 100 nm as a back electrode. When a current was passed through this device, it emitted red light at 4.3V. The measured characteristics of the device are shown in Table 1.

(Element Example 4)
An organic EL element having the structure of the element structure 3 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. Further, as the light emitting layer, the compound (1-1) produced in Example 1 was used as the host material, OXD-7 was used as the electron transport material, and the compound (2-2) produced in Synthesis Example 2 was further used. Was dissolved in THF as a guest material (host: OXD-7: guest = 47: 47: 6: weight ratio), and applied by spin coating at 80 nm. Next, 100 nm of BCP was deposited as a hole blocking layer by vapor deposition. Next, an electron transport layer is formed at a thickness of 200 nm by aluminum / oxine complex (Alq) deposition. On top of that, LiF was vapor-deposited at 0.5 nm and then Al at 100 nm as a back electrode. When a current was passed through this device, it emitted red light at 5.4V. The measured device characteristics are shown in Table 1.

(Element Example 5)
An organic EL element having the structure of the element structure 2 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. Furthermore, as the light emitting layer, the compound (2-2) produced in Synthesis Example 2 was prepared using the compound (1-2) produced in Example 2 as a host material, OXD-7 as an electron transporting material. A guest material dissolved in 1,2-dichloroethane (host: OXD-7: guest = 47: 47: 6 (= mass ratio)) was prepared and applied at 80 nm by spin coating. On top of that, LiF was vapor-deposited at 0.5 nm and then Al at 100 nm as a back electrode. When a current was passed through this device, it emitted red light at 5.4V. The measured device characteristics are shown in Table 1.

(Element Example 6)
An organic EL element having the structure of the element structure 3 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. Furthermore, as a light emitting layer, the compound (1-4) produced in Example 4 was used as a host material, OXD-7 was used as an electron transport material, and the compound (2-2) produced in Synthesis Example 2 was a guest material. Were prepared in THF (host: OXD-7: guest = 47: 47: 6 (= mass ratio)) and applied by spin coating at 80 nm. Next, 100 nm of BCP was deposited as a hole blocking layer by vapor deposition. Next, an electron transport layer is formed at a thickness of 200 nm by aluminum-oxine complex (Alq) deposition. On top of that, LiF was vapor-deposited at 0.5 nm and then Al at 100 nm as a back electrode. When current was passed through the device, it emitted red light at 6.6V. The measured device characteristics are shown in Table 1.

(Element Example 7)
An organic EL element having the structure of the element structure 3 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. Furthermore, as the light emitting layer, the compound (2-2) produced in Synthesis Example 2 was prepared using the compound (1-5) produced in Example 5 as a host material and OXD-7 as an electron transport material. A guest material dissolved in THF (host: OXD-7: guest = 47: 47: 6 (= mass ratio)) was prepared and applied by spin coating at 80 nm. Next, 100 nm of BCP was deposited as a hole blocking layer by vapor deposition. Next, an electron transport layer is formed at a thickness of 200 nm by aluminum-oxine complex (Alq) deposition. On top of that, LiF was vapor-deposited at 0.5 nm and then Al at 100 nm as a back electrode. When current was passed through the device, it emitted red light at 5.8V. The measured device characteristics are shown in Table 1.

(Element Example 8)
An organic EL element having the structure of the element structure 1 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. Furthermore, as a light emitting layer, the compound (1-6) produced in Example 6 was used as a host material, OXD-7 was used as an electron transport material, and the compound (2-1) produced in Synthesis Example 1 was a guest. A material dissolved in 1,2-dichloroethane (host: OXD-7: guest = 47: 47: 6 (= mass ratio)) was prepared and applied at 80 nm by spin coating. On top of this, 30 nm of Ba and then 100 nm of Al were deposited as a back electrode. When current was passed through the device, it emitted red light at 7.2V. The measured device characteristics are shown in Table 1.

(Element Example 9)
An organic EL element having the structure of the element structure 3 of FIG. 1 was formed as follows. The glass substrate on which the ITO transparent electrode was formed was washed, and PEDT: PSS was deposited at 35 nm by spin coating. Furthermore, as the light emitting layer, the compound (2-2) produced in Synthesis Example 2 was prepared using the compound (1-6) produced in Example 6 as a host material and OXD-7 as an electron transport material. A guest material dissolved in THF (host: OXD-7: guest = 47: 47: 6 (= mass ratio)) was prepared and applied by spin coating at 80 nm. Next, 100 nm of BCP was deposited as a hole blocking layer by vapor deposition. Next, an electron transport layer is formed at a thickness of 200 nm by aluminum-oxine complex (Alq) deposition. On top of that, LiF was vapor-deposited at 0.5 nm and then Al at 100 nm as a back electrode. When current was passed through the device, it emitted red light at 5.3V. The measured device characteristics are shown in Table 1.

The characteristics of the organic EL elements produced in Element Examples 1 to 9 are summarized in Table 1 below.

(Solubility test)
The solubility of the comparative compound Y (Ir (ppy) ₂ acac) represented by the following structural formula in toluene was tested at room temperature. Toluene solvent was completely dissolved at 41.728 g with respect to 32.5 mg of comparative compound Y (Ir (ppy) ₂ acac) (solubility 0.08 wt%).

  Subsequently, when the compound (1-1) obtained in Example 1 was similarly dissolved in toluene, 0.955 g of a toluene solvent was required for 29.1 mg of the compound (1-1) (solubility 3). 0.0 wt%). Similarly, the solubility test with toluene was also performed for the compounds (1-2) to (1-6) obtained in Examples 2 to 6. The results are summarized and Table 2 below shows the solubility of each compound.

  As a result, the compound (1-1) in which the carbon chain is extended by 8 carbon atoms is 37.5 times (3.0 / 0.08) as compared with the comparative compound Y in which the organic ligand is unsubstituted. In the compound (1-4) in which one methyl group of acetylacetonate is replaced with an alkoxy group, the solubility is increased 233.75 times (18.7 / 0.08). It was. Thus, it can be seen that the solubility of the iridium complex of the present invention in which an alkyl chain or an alkoxy group is introduced into the organic ligand portion is remarkably improved as compared with the unsubstituted comparative compound Y.

The present invention provides a novel iridium complex useful as a material for an organic EL device, and is industrially useful.
In addition, the present invention provides a phosphorescent material having excellent solubility and dispersibility, which makes it possible to produce a light emitting layer of an organic electroluminescent element (organic EL element) by a wet film forming method. Moreover, by using the material of the present invention, even if the light emitting layer is manufactured by a wet film forming method, it is excellent in luminous efficiency and device lifetime, and is an extremely effective organic EL device manufacturing material, its manufacturing method, and its method. The organic EL device is provided and is extremely useful industrially.

  Therefore, the present invention has industrial applicability.

It is a figure which shows the structure of the element structure 1, the element structure 2, and the element structure 3 in an element example.

Claims (1)

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

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom, an alkyl group, a halogen atom, an alkoxy group, a halogenated alkyl group, A dialkylamino group and a diarylamino group, each of which may be bonded to another substituent R ⁹ and R ¹⁰ are each independently an alkyl group, an aryl group, an alkoxy group or a halogenated group; Represents an alkyl group, R ¹¹ represents a hydrogen atom, an alkyl group, an aryl group or a halogenated alkyl group, and R ⁹ , R ¹⁰ and R ¹¹ represent a polymerizable group or a group obtained by polymerizing the polymerizable group. Provided that at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ has 5 or more carbon atoms. Alkyl group, aralkyl group The .n representing the alkoxy group is an integer of 1 or 2, n1 is an integer of 1 or 2, the sum of n and n1 is 3.)

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