JP5435386B2 - Materials for organic electroluminescence devices - Google Patents

Description

The present invention relates to an organic electroluminescent element showing a high color purity and brightness for the organic electroluminescent device is used in a planar light source or display material and lower drive voltage.

  An organic electroluminescence (EL) element that emits light when an electron injected from a cathode and a hole injected from an anode are recombined in an organic phosphor sandwiched between these two electrodes is a solid light emitting display element. In recent years, research and development has been actively conducted.

This study was conducted by Eastman Kodak's C.I. W. Tang et al., Appl. Phys. Lett. 51, 913, published in 1987, which originated from an EL element with an organic thin film laminated. In this report, a metal chelate complex is used for the light emitting layer and an amine compound is used for the hole injection layer. Thus, green light emission having a luminance of several thousand (cd / m ² ) at a DC voltage of 6 to 10 V and a maximum luminous efficiency of 1.5 (lm / W) is obtained. It can be said that the organic EL elements currently being developed by various research institutes basically follow the configuration of Eastman Kodak Company.

  In addition, biimidazole derivatives have been reported by Ali Reza Mola Ebrahimlo et al. As heterocyclic compounds (see Non-Patent Document 1). In addition, as derivatives of quinoxaline, S. Although reported by Ganapaty et al. (See Non-Patent Documents 2 to 3), it has not been studied as a material for an organic electroluminescence element.

Australian Journal of Chemistry, 62, 126-132 2009 Indian Journal of Heterocyclic Chemistry, No. 16, Jan. -March, pp. 283-286 2007 Asian Journal of Chemistry, No. 2040, no. 5,3353-3356, 2008

An object of the present invention is to provide a material for an organic EL device that has a high fluorescence quantum yield and has little damage to the organic material during purification by a sublimation method or the like and is easily purified. Another object of the present invention is to provide an organic EL device that has high brightness, high efficiency, and long life, with little damage to organic compounds when the organic EL device is prepared by vapor deposition .

As a result of intensive studies to solve the above problems, the present inventors have arrived at the present invention.
That is, this invention relates to the material for organic electroluminescent elements represented by the following general formula [1].
General formula [1]

[Wherein R ^{1 to} R ⁸ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted Or an unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, a substituted amino group, A substituted silyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, or an arylsulfonyl group is represented. Further, R ^{1 to} R ⁴ , R ^{5 to} R ⁶ , and R ^{7 to} R ⁸ may be bonded to each other to form a ring. ]
The present invention also relates to the material for an organic electroluminescent element, wherein R ⁵ and R ⁶ and / or R ⁷ and R ⁸ are integrally formed to form a ring.
Moreover, this invention relates to the said material for organic electroluminescent elements represented by following General formula [2].
General formula [2]

[Wherein R ^{9 to} R ²⁰ each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted Or an unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, a substituted amino group, A substituted silyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, or an arylsulfonyl group is represented. In addition, R ^{9 to} R ²⁰ may form a ring by bonding adjacent groups to each other. ]
Moreover, this invention is an organic electroluminescent element which has at least 1 layer of organic layer containing a light emitting layer between a pair of electrodes which consist of an anode and a cathode, Comprising: At least 1 layer contains the said organic electroluminescent element material The present invention relates to an organic electroluminescence element.

  The material for an organic EL device of the present invention is characterized by being particularly excellent in blue light emission due to its specific structure, being difficult to cause concentration quenching, and being able to achieve both high emission luminance and a long lifetime. Organic EL devices created using this material can be used suitably as flat panel displays and flat light emitters, such as light sources for copiers and printers, light sources for liquid crystal displays and instruments, display boards, indicator lights, etc. Application to is possible.

FIG. 1 is an EL emission spectrum of Example 101. FIG. 2 is an EL emission spectrum of Example 102.

  Hereinafter, the present invention will be described in detail.

In General Formula [1], General Formula [2], and General Formula [3], R ^{1 to} R ⁸ and R ^{9 to} R ²⁰ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent group. Aliphatic hydrocarbon group, substituted or unsubstituted monovalent aromatic hydrocarbon group, substituted or unsubstituted monovalent aliphatic heterocyclic group, substituted or unsubstituted monovalent aromatic heterocyclic group, cyano Group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, substituted amino group, substituted silyl group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, or arylsulfonyl Represents a group.

  As used herein, the halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Examples of the monovalent aliphatic hydrocarbon group here include an alkyl group, an alkenyl group, an alkynyl group, and a cycloalkyl group.

  Here, as the alkyl group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, hexyl group, heptyl group, octyl group , An alkyl group having 1 to 18 carbon atoms such as a decyl group, a dodecyl group, a pentadecyl group, and an octadecyl group.

  Examples of the alkenyl group include vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-octenyl group, 1-decenyl group, 1 -An alkenyl group having 2 to 18 carbon atoms such as an octadecenyl group.

  Examples of the alkynyl group include ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, 1-octynyl group, 1-decynyl group and 1-octadecynyl group. Examples thereof include alkynyl groups having 2 to 18 carbon atoms.

  Examples of the cycloalkyl group include cycloalkyl groups having 3 to 18 carbon atoms such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclooctadecyl group.

  Furthermore, examples of the monovalent aromatic hydrocarbon group include a monovalent monocyclic ring, a condensed ring, and a ring assembly hydrocarbon group.

  Here, examples of the monovalent monocyclic aromatic hydrocarbon group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 2,4-xylyl group, a p-cumenyl group, and a mesityl group. Examples thereof include monovalent monocyclic aromatic hydrocarbon groups having 6 to 18 carbon atoms.

  Examples of the monovalent condensed ring hydrocarbon group include 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 9-phenanthryl group, 1- Examples thereof include monovalent condensed ring hydrocarbon groups having 10 to 18 carbon atoms such as acenaphthyl group, 2-azurenyl group, 1-pyrenyl group and 2-triphenylyl group.

  Examples of the monovalent ring assembly hydrocarbon group include monovalent ring assembly hydrocarbon groups having 12 to 18 carbon atoms such as o-biphenylyl group, m-biphenylyl group, p-biphenylyl group, and terphenyl group. .

  Furthermore, examples of the monovalent aliphatic heterocyclic group include monovalent aliphatic heterocyclic groups having 3 to 18 carbon atoms such as a 2-pyrazolino group, a piperidino group, a morpholino group, and a 2-morpholinyl group.

  Examples of the monovalent aromatic heterocyclic group include triazolyl group, 3-oxadiazolyl group, 2-furyl group, 3-furyl group, 2-thienyl group, 3-thienyl group, 1-pyrrolyl group and 2-pyrrolyl group. 3-pyrrolyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 2-oxazolyl group, 3-isoxazolyl group, 2-thiazolyl group, 3-isothiazolyl group, 2-imidazolyl group 3-pyrazolyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 2-quinoxalinyl group , 2-benzofuryl group, 2-benzothienyl group, N-indolyl group, N-carbazolyl group, N-acridinyl group, (2,2′-bithienyl) -4-yl group It said compound of 2 to 18 carbon atoms, and the like.

  Examples of the alkoxyl group include C1-C8 alkoxyl groups such as methoxy group, ethoxy group, propoxy group, butoxy group, tert-butoxy group, octyloxy group, and tert-octyloxy group.

  Examples of the aryloxy group include aryloxy groups having 6 to 14 carbon atoms such as phenoxy group, 4-tert-butylphenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, and 9-anthryloxy group. .

  The substituted amino group includes N-methylamino group, N-ethylamino group, N, N-diethylamino group, N, N-diisopropylamino group, N, N-dibutylamino group, N-benzylamino group, N , N-dibenzylamino group, N-phenylamino group, N-phenyl-N-methylamino group, N, N-diphenylamino group, N, N-bis (m-tolyl) amino group, N, N-bis (P-tolyl) amino group, N, N-bis (p-biphenylyl) amino group, bis [4- (4-methyl) biphenylyl] amino group, N-α-naphthyl-N-phenylamino group, N-β Examples thereof include substituted amino groups having 2 to 24 carbon atoms such as naphthyl-N-phenylamino group.

  Furthermore, the substituted silyl group is a substituted or unsubstituted alkyl group, or a silyl group substituted by a substituted or unsubstituted aryl group. A monoalkylsilyl group, a monoarylsilyl group, a dialkylsilyl group, a diarylsilyl group And substituted silyl groups such as a group, a trialkylsilyl group, and a triarylsilyl group.

  Here, as the monoalkylsilyl group, a monoalkylsilyl group such as a monomethylsilyl group, a monoethylsilyl group, a monobutylsilyl group, a monoisopropylsilyl group, a monodecanesilyl, a monoicosanesilyl group, or a monotriacontanesilyl group Is mentioned.

  Examples of the monoarylsilyl group include monoarylsilyl such as monophenylsilyl group, monotolylsilyl group, mononaphthylsilyl group, and monoanthrylsilyl group.

  Examples of the dialkylsilyl group include dialkylsilyl groups such as dimethylsilyl group, diethylsilyl group, dimethylethylsilyl group, diisopropylsilyl group, dibutylsilyl group, dioctylsilyl group, and didecanesilyl group.

  Examples of the diarylsilyl group include diarylsilyl such as diphenylsilyl group and ditolylsilyl group.

  Examples of the trialkylsilyl group include trialkylsilyl groups such as trimethylsilyl group, triethylsilyl group, dimethylethylsilyl group, triisopropylsilyl group, tributylsilyl group, and trioctylsilyl group.

  Examples of the triarylsilyl group include triarylsilyl such as triphenylsilyl group and tolylsilylsilyl group.

  Examples of the acyl group include acyl groups having 2 to 14 carbon atoms such as an acetyl group, a propionyl group, a pivaloyl group, a cyclohexylcarbonyl group, a benzoyl group, a toluoyl group, an anisoyl group, and a cinnamoyl group.

  Moreover, as an alkoxycarbonyl group, C2-C14 alkoxycarbonyl groups, such as a methoxycarbonyl group, an ethoxycarbonyl group, a benzyloxycarbonyl group, are mention | raise | lifted.

  Examples of the aryloxycarbonyl group include C2-C14 aryloxycarbonyl groups such as a phenoxycarbonyl group and a naphthyloxycarbonyl group.

  The monovalent aliphatic hydrocarbon group, monovalent aromatic hydrocarbon group, monovalent aliphatic heterocyclic group, and monovalent aromatic heterocyclic group described above are further substituted with other substituents. May be. These substituents may be bonded to each other to form a ring. Such substituents include halogen atoms, cyano groups, alkoxyl groups, aryloxy groups, alkylthio groups, arylthio groups, substituted amino groups, substituted silyl groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, alkylsulfonyl groups. And arylsulfonyl group. Examples of these substituent groups include those described above.

Of the substituents that may be bonded to R ^{1 to} R ⁸ and R ^{9 to} R ²⁰ listed above, more preferred are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a biphenyl group, and a naphthyl group. Group, styryl group and the like, particularly preferably a hydrogen atom, a phenyl group, a biphenyl group and a styryl group. When these substituents are used, the molecular weight is relatively small, the compound (material) can be easily sublimated by vapor deposition or the like, and it is also preferable from the viewpoint of stability. However, this does not apply when vapor deposition is not performed.

In general formula [1], general formula [2], and in the general formula ^{[3], R 1 ~R 4} , R 5 ~R 6, R 7 ~R 8, R 9 ~R 12, R 13 ~R ¹⁶ and R ^{17 to} R ²⁰ may be bonded to each other to form a ring, and specific examples thereof include a benzene ring, a naphthalene ring, a phenanthrene ring, a pyrazine ring, and a piperazine ring.
Although the following Table 1 shows the representative example of the compound which is the material for organic EL elements of the present invention, the present invention is not limited to this representative example.

  An organic EL element is composed of an element in which a single layer or a multilayer organic layer is formed between an anode and a cathode. Here, a single layer type organic EL element is an element composed of only a light emitting layer between an anode and a cathode. Point to. On the other hand, the multilayer organic EL element facilitates injection of holes and electrons into the light emitting layer in addition to the light emitting layer, and facilitates recombination of holes and electrons in the light emitting layer. For the purpose of this, it refers to a layer in which a hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer, and the like are laminated. Therefore, typical element configurations of the multilayer organic EL element include (1) anode / hole injection layer / light emitting layer / cathode, and (2) anode / hole injection layer / hole transport layer / light emitting layer / cathode. (3) Anode / hole injection layer / light emitting layer / electron injection layer / cathode, (4) Anode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode, (5) Anode / positive Hole injection layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (6) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (7) An element structure in which a multilayer structure of anode / light emitting layer / hole blocking layer / electron injection layer / cathode, (8) anode / light emitting layer / electron injection layer / cathode, etc., is considered.

  Moreover, each organic layer mentioned above may be formed by the layer structure of two or more layers, respectively, and several layers may be laminated | stacked repeatedly. As such an example, an element configuration called “multi-photon emission” in which a part of the above-described multilayer organic EL element is multilayered has been proposed in recent years for the purpose of improving light extraction efficiency. For example, in an organic EL device composed of a glass substrate / anode / hole transport layer / electron transporting light emitting layer / electron injection layer / charge generating layer / light emitting unit / cathode, the charge generating layer and the light emitting unit A method of laminating a plurality of layers is an example.

For the hole injection layer, a hole injection material that exhibits an excellent hole injection effect with respect to the light emitting layer and that can form a hole injection layer excellent in adhesion to the anode interface and thin film formability is used. In addition, when such materials are laminated in multiple layers and a material having a high hole injection effect and a material having a high hole transport effect are laminated, the materials used for each are called a hole injection material and a hole transport material. Sometimes. The organic electroluminescent element material of the present invention can be suitably used for both hole injection materials and hole transport materials. These hole injection materials and hole transport materials need to have high hole mobility and low ionization energy, usually 5.5 eV or less. As such a hole injection layer, a material that transports holes to the light emitting layer with a lower electric field strength is preferable. Further, at the time of applying an electric field of, for example, 10 ⁴ to 10 ⁶ V / cm, What is 10 ^<-6 > cm ^{< 2} > / V * second is preferable. Other hole injection materials and hole transport materials that can be used by mixing with the organic electroluminescence device material of the present invention are not particularly limited as long as they have the above-mentioned preferable properties. An arbitrary material can be selected and used from those commonly used as a charge transport material for holes in an optical transmission material and known materials used for a hole injection layer of an organic EL element.

  Specific examples of such hole injection materials and hole transport materials include triazole derivatives (see US Pat. No. 3,112,197) and oxadiazole derivatives (US Pat. No. 3,189). , 447, etc.), imidazole derivatives (see Japanese Patent Publication No. 37-16096), polyarylalkane derivatives (US Pat. Nos. 3,615,402 and 3,820,989). No. 3,542,544, JP-B-45-555, JP-A-51-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148 55-108667, 55-156953, 56-36656, etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. No. 3,180, No. 29, No. 4,278,746, JP-A 55-88064, No. 55-88065, No. 49-105537, No. 55-51086, No. 56-80051. No. 56-88141, No. 57-45545, No. 54-112437, No. 55-74546, etc.), phenylenediamine derivatives (US Pat. No. 3,615,404, Japanese Patent Publication Nos. 51-10105, 46-3712, 47-25336, JP 54-53435, 54-110536, 54-1119925, etc.), Ali- Ruamine derivatives (US Pat. Nos. 3,567,450, 3,180,703, 3,240,597, No. 658,520, No. 4,232,103, No. 4,175,961, No. 4,012,376, JP-B 49-35702, No. 39 -27577, JP-A-55-144250, JP-A-56-119132, JP-A-56-22437, West German Patent No. 1,110,518, etc.), amino-substituted chalcone derivatives (US patents) No. 3,526,501 etc.), oxazole derivatives (disclosed in US Pat. No. 3,257,203 etc.), styryl anthracene derivatives (see JP 56-46234 A, etc.) ), Fluorenone derivatives (see JP-A-54-110837, etc.), hydrazone derivatives (US Pat. No. 3,717,462, JP-A-54-59143, 55-52063, 55-52064, 55-46760, 55-85495, 57-11350, 57-148749, JP-A-2-311591, etc. Stilbene derivatives (Japanese Patent Laid-Open Nos. 61-210363, 61-228451, 61-14642, 61-72255, 62-47646, 62-36674) 62-10652, 62-30255, 60-93455, 60-94462, 60-174749, 60-175052, etc.), silazane derivatives (US) Patent No. 4,950,950), polysilane (JP-A-2-204996), aniline copolymer (JP-A-2-282263), a conductive polymer disclosed in Japanese Patent Laid-Open No. 1-211399 oligomer - (particularly thiophene oligomer -) and the like.

  As the hole injecting material and the hole transporting material, those described above can be used. Porphyrin compounds (Japanese Patent Laid-Open No. 63-295965), aromatic tertiary amine compounds and styrylamine compounds (US Pat. No. 4,127,412, JP-A-53-27033, 54-58445, 54-149634, 54-64299, 55-79450, 55-144250 No. 56-119132, No. 61-295558, No. 61-98353, No. 63-295695, etc.) can also be used. For example, 4,4′-bis (N- (1-naphthyl) -N-phenylamino) biphenyl having two condensed aromatic rings in the molecule described in US Pat. No. 5,061,569, etc. And 4,4 ′, 4 ″ -tris (N- (3-methylphenyl)-, in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type. N-phenylamino) triphenylamine, etc. In addition, examples of the hole injection material include phthalocyanine derivatives such as copper phthalocyanine and hydrogen phthalocyanine, and other aromatic dimethylidene compounds, p-type Si, p Inorganic compounds such as type SiC can also be used as the material for the hole injection material and the hole transport material.

  Specific examples of the aromatic tertiary amine derivative include, for example, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N , N ′, N ′-(4-methylphenyl) -1,1′-phenyl-4,4′-diamine, N, N, N ′, N ′-(4-methylphenyl) -1,1′- Biphenyl-4,4′-diamine, N, N′-diphenyl-N, N′-dinaphthyl-1,1′-biphenyl-4,4′-diamine, N, N ′-(methylphenyl) -N, N '-(4-N-butylphenyl) -phenanthrene-9,10-diamine, N, N-bis (4-di-4-tolylaminophenyl) -4-phenyl-cyclohexane, N, N'-bis (4 '-Diphenylamino-4-biphenylyl) -N, N'-diphenyl Nzine, N, N′-bis (4′-diphenylamino-4-phenyl) -N, N′-diphenylbenzidine, N, N′-bis (4′-diphenylamino-4-phenyl) -N, N ′ -Di (1-naphthyl) benzidine, N, N'-bis (4'-phenyl (1-naphthyl) amino-4-phenyl) -N, N'-diphenylbenzidine, N, N'-bis (4'- Phenyl (1-naphthyl) amino-4-phenyl) -N, N′-di (1-naphthyl) benzidine and the like can be mentioned, and these can be used for both hole injection materials and hole transport materials.

  In order to form this hole injection layer, the above compound is thinned by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Although there is no restriction | limiting in particular, Usually, they are 5 nm-5 micrometers.

  On the other hand, for the electron injection layer, an electron injection material that exhibits an excellent electron injection effect with respect to the light emitting layer and that can form an electron injection layer excellent in adhesion to the cathode interface and thin film formability is used. Examples of such electron injection materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, fluorenone derivatives, anthraquinodimethane derivatives, diphenoquinone derivatives, thiopyrandioxide derivatives, perylenetetracarboxylic acid derivatives, fluorenylidenemethane. Derivatives, anthrone derivatives, silole derivatives, triarylphosphine oxide derivatives, calcium acetylacetonate, sodium acetate and the like. In addition, inorganic / organic composite materials doped with metal such as cesium in bathophenanthroline (Proceedings of the Society of Polymer Science, Vol. 50, No. 4, 660, published in 2001) and the 50th Association of Applied Physics Lecture Proceedings, No. Examples of electron injection materials include BCP, TPP, T5MPyTZ, etc. published on page 3, 1402, 2003. Electrons can be transported by forming a thin film necessary for device fabrication and injecting electrons from the cathode. If it is material, it will not specifically limit to these.

  Among the electron injection materials, particularly effective electron injection materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, silole derivatives, and triarylphosphine oxide derivatives. As a preferable metal complex compound that can be used in the present invention, a metal complex of 8-hydroxyquinoline or a derivative thereof is suitable. Specific examples of the metal complex of 8-hydroxyquinoline or its derivatives include tris (8-hydroxyquinolinato) aluminum, tris (2-methyl-8-hydroxyquinolinato) aluminum, tris (4-methyl- 8-hydroxyquinolinato) aluminum, tris (5-methyl-8-hydroxyquinolinato) aluminum, tris (5-phenyl-8-hydroxyquinolinato) aluminum, bis (8-hydroxyquinolinato) G) (1-naphtholato) aluminum, bis (8-hydroxyquinolinato) (2-naphtholato) aluminum, bis (8-hydroxyquinolinato) (phenolate) aluminum, bis (8 -Hydroxyquinolinato) (4-cyano-1-naphtholato) aluminum, bis (4-methyl-8) Hydroxyquinolinato) (1-naphtholato) aluminum, bis (5-methyl-8-hydroxyquinolinato) (2-naphtholato) aluminum, bis (5-phenyl-8-hydroxyquinolina) G) (phenolate) aluminum, bis (5-cyano-8-hydroxyquinolinato) (4-cyano-1-naphtholato) aluminum, bis (8-hydroxyquinolinato) chloroaluminum, bis Aluminum complex compounds such as (8-hydroxyquinolinato) (o-cresolato) aluminum, tris (8-hydroxyquinolinato) gallium, tris (2-methyl-8-hydroxyquinolinato) gallium , Tris (4-methyl-8-hydroxyquinolinato) gallium, tris (5-methyl-8-hydroxyquinolinato) Gallium, tris (2-methyl-5-phenyl-8-hydroxyquinolinato) gallium, bis (2-methyl-8-hydroxyquinolinato) (1-naphtholato) gallium, bis (2-methyl) -8-hydroxyquinolinato) (2-naphtholato) gallium, bis (2-methyl-8-hydroxyquinolinato) (phenolate) gallium, bis (2-methyl-8-hydroxyquinolina) -To) (4-cyano-1-naphtholato) gallium, bis (2,4-dimethyl-8-hydroxyquinolinato) (1-naphtholato) gallium, bis (2,5-dimethyl-8) -Hydroxyquinolinato) (2-naphtholato) gallium, bis (2-methyl-5-phenyl-8-hydroxyquinolinato) (phenolate) gallium, bis (2-methyl-5- Cyano-8-hydroxyquinolinato) (4-cyano-1-naphtholato) gallium, bis (2-methyl-8-hydroxyquinolinato) chlorogallium, bis (2-methyl-8-hydroxyquino) In addition to gallium complex compounds such as linato) (o-cresolato) gallium, 8-hydroxyquinolinatolithium, bis (8-hydroxyquinolinato) copper, bis (8-hydroxyquinolinato) Metal complex compounds such as manganese, bis (10-hydroxybenzo [h] quinolinato) beryllium, bis (8-hydroxyquinolinato) zinc, bis (10-hydroxybenzo [h] quinolinato) zinc It is done.

  Among the electron injection materials that can be used in the present invention, preferred nitrogen-containing five-membered ring derivatives include oxazole derivatives, thiazol derivatives, oxadiazol derivatives, thiadiazol derivatives, and triazole derivatives. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazol, 2 , 5-bis (1-phenyl) -1,3,4-oxadiazol, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) 1,3,4-oxadiazol, 2,5-bis (1-naphthyl) -1,3,4-oxadiazol, 1,4-bis [2- (5-phenyloxadiazolyl).) Benzene, 1,4-bis [2- ( 5-Phenyloxadiazolyl) -4-tert-butyl Nzene], 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-thiadiazol, 2,5-bis (1-naphthyl) -1,3,4 -Thiadiazol, 1,4-bis [2- (5-phenylthiadiazolyl). ) Benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1,3,4 -Triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

  Furthermore, a hole blocking material that can prevent holes from passing through the light emitting layer from reaching the electron injection layer and form a layer having excellent thin film formability is used for the hole blocking layer. Examples of such hole blocking materials include aluminum complex compounds such as bis (8-hydroxyquinolinato) (4-phenylphenolato) aluminum, and bis (2-methyl-8-hydroxyquinolina). -To) (4-phenylphenolato) gallium complex compounds such as gallium, and nitrogen-containing condensed aromatic compounds such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). .

  The material for an organic EL device of the present invention is a compound having strong fluorescence in a solid state, and is suitable as a light emitting material in a light emitting layer. Furthermore, when it is used as a doping material combined with other host materials, it is possible to select a high light emission efficiency and light emission wavelength by doping at an optimum ratio in the light emitting layer. Further, by using another doping material as the doping material together with the material for the organic EL device of the present invention, light emission from blue to red and further to white can be obtained.

  Moreover, when using the organic EL element material of this invention for a light emitting layer, you may contain another host material and doping material. In this case, the concentration of the doping material is preferably in the range of 0.001 to 30% by weight, more preferably in the range of 0.01 to 10% by weight with respect to the host material. More preferably, it is contained in the range of 1 to 5% by weight.

  Host materials that can be used in combination with the organic EL device material of the present invention include quinoline metal complexes, oxadiazoles, benzothiazole metal complexes, benzoxazole metal complexes, benzimidazole metal complexes, triazoles, imidazoles, oxazoles, and oxadiazoles. , Stilbene, butadiene, benzidine type triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine fluorenone, diaminoanthracene type triphenylamine, diaminophenanthrene type triphenylamine, anthraquinodimethane, diphenoquinone, thiadiazole, tetrazole, Perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane, triphenylene, anthrone, etc. and their derivatives, and polyvinyl Carbazole, polymeric materials such conductive polymers polysilane.

  It is also possible to change the emission color by using a further doping material together with the organic EL element material of the present invention. As doping materials used together with the organic EL device material of the present invention, anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone, naphthaloperinone, diphenylbutadiene, tetraphenyl Butadiene, coumarin, oxadiazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, imine, diphenylethylene, vinylanthracene, diaminocarbazole, pyran, thiopyran, polymethine, merocyanine, There are imidazole chelating oxinoid compounds, quinacridone, rubrene, etc. and their derivatives. The present invention is not limited.

  In addition to the light emitting material and the doping material, if necessary, a hole injection material or an electron injection material can be used for the light emitting layer.

Furthermore, the material used for the anode of the organic EL device of the present invention is preferably a material having a work function (4 eV or more) metal, alloy, electrically conductive compound or a mixture thereof as an electrode substance. Specific examples of such an electrode substance include metals such as Au, and conductive materials such as CuI, ITO, SNO ₂ , and ZNO. In order to form this anode, a thin film can be formed from these electrode materials by a method such as vapor deposition or sputtering. The anode desirably has such a characteristic that when light emitted from the light emitting layer is extracted from the anode, the transmittance of the anode for light emission is greater than 10%. The sheet resistance of the anode is preferably several hundred Ω / □ or less. Further, although the film thickness of the anode depends on the material, it is usually selected in the range of 10 Nm to 1 μm, preferably 10 to 200 nm.

  The material used for the cathode of the organic EL device of the present invention is a material having a small work function (4 eV or less) metal, alloy, electrically conductive compound and a mixture thereof as an electrode substance. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / silver alloy, aluminum / aluminum oxide, aluminum / lithium alloy, indium, and rare earth metals. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Here, when light emitted from the light-emitting layer is extracted from the cathode, the transmittance of the cathode for light emission is preferably greater than 10%. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 Nm.

  Regarding the method for producing the organic EL device of the present invention, an anode, a light emitting layer, a hole injection layer as necessary, and an electron injection layer as necessary are formed by the above materials and methods, and finally a cathode is formed. do it. Moreover, an organic EL element can also be produced from the cathode to the anode in the reverse order.

  This organic EL element is manufactured on a translucent substrate. This translucent substrate is a substrate that supports the organic EL element, and for the translucency, it is desirable that the transmittance of light in the visible region of 400 to 700 nm is 50% or more, preferably 90% or more, Further, it is preferable to use a smooth substrate.

  These substrates have mechanical and thermal strengths and are not particularly limited as long as they are transparent. For example, glass plates, synthetic resin plates and the like are preferably used. Examples of the glass plate include plates made of soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz, and the like. Examples of the synthetic resin plate include polycarbonate resin, acrylic resin, polyethylene terephthalate resin, polyethersulfide resin, and polysulfone resin.

  As a method for forming each layer of the organic EL device of the present invention, a dry film forming method such as vacuum deposition, electron beam irradiation, sputtering, plasma, ion plating, or spin coating, dipping, flow coating, etc. , A wet film forming method such as an ink jet method, a method of depositing a light emitter on a donor film, and Japanese Patent Application Laid-Open No. 2002-534782 and S.A. T.A. Lee, et al. , Proceedings of SID'02, p. LITI (Laser Induced Thermal Imaging) method described in 784 (2002), printing (offset printing, flexographic printing, gravure printing, screen printing), inkjet, and the like can also be applied.

  The organic layer is particularly preferably a molecular deposited film. Here, the molecular deposited film is a thin film formed by deposition from a material compound in a gas phase state or a film formed by solidifying from a material compound in a solution state or a liquid phase state. Can be classified from a thin film (accumulated film) formed by the LB method according to a difference in an agglomerated structure and a higher-order structure and a functional difference resulting therefrom. Also, as disclosed in JP-A-57-51781, a binder such as a resin and a material compound are dissolved in a solvent to form a solution, and then this is thinned by a spin coat method or the like. Also, an organic layer can be formed. The film thickness of each layer is not particularly limited, but if the film thickness is too thick, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. Conversely, if the film thickness is too thin, the pinhole is used. Or the like, and even when an electric field is applied, it is difficult to obtain sufficient light emission luminance. Accordingly, the thickness of each layer is suitably in the range of 1 nm to 1 μm, but more preferably in the range of 10 nm to 0.2 μm.

  Further, in order to improve the stability of the organic EL element with respect to temperature, humidity, atmosphere and the like, a protective layer may be provided on the surface of the element, or the entire element may be covered or sealed with a resin or the like. In particular, when the entire element is covered or sealed, a photocurable resin that is cured by light is preferably used.

  The current applied to the organic EL element of the present invention is usually a direct current, but a pulse current or an alternating current may be used. The current value and voltage value are not particularly limited as long as the element is not damaged, but considering the power consumption and life of the element, it is desirable to emit light efficiently with as little electrical energy as possible.

  The organic EL device driving method of the present invention can be driven not only by the passive matrix method but also by the active matrix method. Further, the method for extracting light from the organic EL device of the present invention is applicable not only to the method of bottom emission for extracting light from the anode side but also to the method of top emission for extracting light from the cathode side. These methods and techniques are described in Shinji Kido, “All about organic EL”, published by Nihon Jitsugyo Shuppansha (published in 2003).

  The main methods of the full color method of the organic EL element of the present invention include a three-color coating method, a color conversion method, and a color filter method. In the three-color coating method, there are a vapor deposition method using a shadow mask, an ink jet method and a printing method. In addition, Special Tables 2002-534882 and S.A. T.A. Lee, et al. , Proceedings of SID'02, p. 784 (2002) can also be used. The laser thermal transfer method (also referred to as Laser Induced Thermal Imaging, LITI method) can also be used. In the color conversion method, a blue light emitting layer is used to convert green and red having a longer wavelength than blue through a color conversion (CCM) layer in which fluorescent dyes are dispersed. The color filter method uses a white light emitting organic EL element to extract light of three primary colors through a color filter for liquid crystal. In addition to these three primary colors, a part of white light is directly extracted and used for light emission. Thus, the luminous efficiency of the entire device can be increased.

  Furthermore, the organic EL element of the present invention may adopt a microcavity structure. This is because the organic EL element has a structure in which the light emitting layer is sandwiched between the anode and the cathode, and the emitted light causes multiple interference between the anode and the cathode, but the reflectance and transmission of the anode and the cathode. This is a technology that actively uses the multiple interference effect and controls the emission wavelength extracted from the device by appropriately selecting the optical characteristics such as the rate and the film thickness of the organic layer sandwiched between them. . Thereby, it is also possible to improve the emission chromaticity. For the mechanism of this multiple interference effect, see J.A. Yamada et al., AM-LCD Digest of Technical Papers, OD-2, p. 77-80 (2002).

  As described above, the organic EL device of the present invention can obtain red light emission exhibiting high color purity and luminance at a low driving voltage. Therefore, this organic EL device can be applied to flat panel displays such as wall-mounted televisions and flat light emitters, as well as light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, and indicator lights. Can be considered.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example.

Organic EL Element Material and Compound Synthesis Method of the Present Invention The organic EL element material of the present invention can be obtained by combining the following reaction formulas 1 to 7. Moreover, the compound of this invention was able to be obtained by combining Reaction Formula 1-7.
Reaction formula 1

Reaction formula 2

Reaction formula 3

Reaction formula 4

Reaction formula 5

Reaction formula 6

Reaction formula 7

Example 1
Method for synthesizing compound (1)
Synthesis of 1,2-Di (1-imidazolyl) benzene (101) 1,2-dibromobenzene (0.238 g, 1.01 mmol), imidazole (0.173 g, 2.54 mmol), K _{2 CO 3 (0.284 g, 2.04} mmol), Cu 2 O (0.0078 g, 0.0545 mmol), DMSO and (1.5 mL) was added, followed by stirring for 48 hours at 0.99 ° C.. After cooling to room temperature, the mixture was filtered using celite. Water (5 mL) was added to the filtrate, and the mixture was extracted with ethyl acetate (10 mL × 3). The extract was dried over sodium sulfate. The solvent was removed under reduced pressure, and column chromatography (silica gel, chloroform: methanol = 10: 1) gave 1,2-di (1-imidazolyl) benzene (101; 0.182 g, 87%) as a white solid. Recrystallization from a hexane-chloroform mixed solvent gave colorless crystals. Colorless crystals; mp 133.1-134.9 ° C; ¹ H NMR (300 MHz, CDCl ₃ ) δ 6.74 (s, 2H), 7.11 (s, 2H), 7.44 (s, 2H), 7.46-7.52 (m, 2H), 7.54-7.58 (m, 2H); 7.08 (s, 2H); ¹³ C NMR (75 Hz, CDCl ₃ ) δ 119.4, 127.1, 129.6, 130.5, 132.1, 136.6; IR (KBr / cm ^-1 ) 3101, 3030 , 2360, 1681, 1593, 1520, 1495, 1247, 1176, 1111, 1089, 1065, 1054, 1039, 964, 740. FAB-MS, m / z = 211 ([M + H] ⁺ ).
Synthesis of Diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (1) 1,2-di (1-imidazolyl) benzene (101; 0.210 g, 1.0 in a 30 mL eggplant flask under argon atmosphere mmol) and THF (5 mL) were added, and n-BuLi (1.57 M hexane solution; 1.6 mL, 2.4 mmol) was added dropwise at −78 ° C., followed by stirring at −78 ° C. for 1 hour. While stirring Pd (PPh ₃ ) ₄ (0.0277 g, 0.024 mmol) and THF (2 mL) prepared in another 30 mL eggplant flask at −78 ° C., the reaction solution of the first 30 mL eggplant flask was added dropwise. The reaction temperature was slowly raised and the mixture was stirred at 45 ° C. for 19 hours. Saturated brine (5 mL) was added, and the mixture was extracted with chloroform (10 mL × 3). The extract was dried over sodium sulfate. Distilledazo [1,2-a: 2 ', 1'-c] quinoxaline (1; 0.147 g, 71%) was purified by column chromatography (silica gel, chloroform: methanol = 10: 1) under reduced pressure. Obtained as a white solid. Recrystallization from a hexane-chloroform mixed solvent gave colorless crystals. Colorless crystals; mp 260.9-261.4 ° C; ¹ H NMR (300 MHz, CDCl ₃ ) δ 7.50-7.57 (m, 2H), 7.62 (d, J = 1.2 Hz, 2H), 7.88 (d, J = 1.5 Hz, 2H), 7.84-7.88 (m, 2H); ¹³ C NMR (75 Hz, CDCl ₃ ) δ112.36, 116.8, 124.5, 126.6, 132.8, 135.9; IR (KBr / cm ^-1 ) 1630, 1510, 1413, 1324, 1121, 931, 755, 686, 468, 442, 425, 407. HRMS (ESI) for C ₁₂ H ₉ N ₄ ([M + H] ⁺ ); Calcd. 209.0822, Found 209.0819.
Synthesis of Diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (1) 1,2-di (1-imidazolyl) benzene (101; 0.212 g, 1.0 in a 30 mL eggplant flask under argon atmosphere mmol) and THF (5 mL) were added, and n-BuLi (1.57 M hexane solution; 1.6 mL, 2.4 mmol) was added dropwise at −78 ° C., followed by stirring at −78 ° C. for 1 hour. I ₂ (0.269 g, 1.06 mmol) and THF (4 mL) prepared in another 30 mL eggplant flask were added. The reaction temperature was slowly raised and stirred at 45 ° C. for 24 hours. Saturated brine (5 mL) was added, and the mixture was extracted with chloroform (10 mL × 3). The extract was dried over sodium sulfate. Distilledazo [1,2-a: 2 ', 1'-c] quinoxaline (1; 0.160 g, 68%) was removed by column chromatography (silica gel, chloroform: methanol = 10: 1) under reduced pressure. Obtained as a white solid. ¹ H NMR (300 MHz, CDCl ₃ ) δ 7.50-7.57 (m, 2H), 7.62 (d, J = 1.2 Hz, 2H), 7.88 (d, J = 1.5 Hz, 2H), 7.84-7.88 (m, 2H); ¹³ C NMR (75 Hz, CDCl ₃ ) δ112.36, 116.8, 124.5, 126.6, 132.8, 135.9; IR (KBr / cm ^-1 ) 1630, 1510, 1413, 1324, 1121, 931, 755, 686 , 468, 442, 425, 407. HRMS (ESI) for C ₁₂ H ₉ N ₄ ([M + H] ⁺ ); Calcd 209.0822, Found 209.0819.

Example 2
Method for synthesizing compound (2)
Synthesis of 3,10-Diphenyldiimidazo [1,2-a: 2 ', 1'-c] quinoxaline (2) K ₂ CO ₃ (0.279) dried at 150 ° C for 2 hours in a screw-cap test tube under nitrogen atmosphere g, 1.95 mmol), diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (1; 0.104 g, 0.5 mmol), bromobenzene (0.386 g, 2.5 mmol), Pd (OAc) ₂ (0.0124 g , 0.055 mmol), PPh ₃ (0.0264 g, 0.10 mmol) and DMF (2.5 mL) were added, and the mixture was stirred at 140 ° C. for 48 hours. After cooling to room temperature, the mixture was filtered using celite. To the filtrate was added saturated brine (5 mL), and the mixture was extracted with chloroform (10 mL × 3). The extract was dried over sodium sulfate. The solvent was removed under reduced pressure, and 3,10-diphenyldiimidazo [1,2-a: 2 ', 1 was obtained by column chromatography (silica gel, ethyl acetate) and preparative GPC (JIGEL-1H and 2H linked column, chloroform). '-c] quinoxaline (2; 0.099 g, 55%) was obtained as a white solid. Recrystallization from a hexane-chloroform mixed solvent gave colorless crystals. Colorless crystals; mp 203.1-203.9 ° C; ¹ H NMR (300 MHz, CDCl ₃ ) δ 7.03-7.06 (m, 2H), 7.48-7.57 (m, 14H); ¹³ C NMR (75 Hz, CDCl ₃ ) δ 118.7 , 125.3, 126.2, 129.2, 129.2, 129.7, 130.2, 130.8, 133.8, 137.4; IR (KBr / cm ^-1 ) 1624, 1571, 1463, 1476, 1376, 1347, 1160, 954, 851, 762, 704, 645 , 567, 506, 485, 450, 439, 409. HRMS (ESI) for C ₂₄ H ₁₇ N ₄ ([M + H] ⁺ ); Calcd 361.1448, Found 361.1433.

Example 3
Method for synthesizing compound (4)
Synthesis of 3,10-Bis [4- (trifluoromethyl) phenyl] diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (4) 2 hours at 150 ° C in a screw-cap test tube under nitrogen atmosphere Dried K ₂ CO ₃ (0.277 g, 2.00 mmol), diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (1; 0.118 g, 0.57 mmol), 1-bromo-4- (trifluoromethyl ) benzene (0.459 g, 2.0 mmol), Pd (OAc) ₂ (0.0125 g, 0.056 mmol), PPh ₃ (0.0259 g, 0.11 mmol) and DMF (2.5 mL) were added, and the mixture was stirred at 140 ° C. for 48 hours. After cooling to room temperature, the mixture was filtered using celite. To the filtrate was added saturated brine (5 mL), and the mixture was extracted with chloroform (10 mL × 3). The extract was dried over sodium sulfate. The solvent was distilled off under reduced pressure, and 3,10-bis [4- (trifluoromethyl) phenyl] diimidazo [1 was obtained by column chromatography (silica gel, ethyl acetate) and preparative GPC (JIGEL-1H and 2H linked column, chloroform). , 2-a: 2 ', 1'-c] quinoxaline (4; 0.116 g, 47%) was obtained as a white solid. Recrystallization from a hexane-chloroform mixed solvent gave colorless crystals. Colorless crystals; mp 287.5-287.9 ° C; ¹ H NMR (300 MHz, CDCl ₃ ) δ 7.14-7.18 (m, 2H), 7.45-7.49 (m, 2H), 7.58 (s, H), 7.71 (d, J = 8.1 Hz, 4H), 7.81 (d, J = 8.4 Hz, 4H); IR (KBr / cm ^-1 ) 1618, 1573, 1496, 1376, 1327, 1255, 1167, 1122, 1073, 1017, 955, 841 , 754, 606, 440. Anal. Calcd for C ₂₆ H ₁₄ F ₆ N ₄ : C, 62.91; H, 2.84; N, 11.29. Found: C, 62.98; H, 2.48; N, 11.18.

Example 4
Method for synthesizing compound (5)
Synthesis of 3,10-Bis (4-methoxyphenyl) diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (5) Dried in a screw-cap test tube at 150 ° C for 2 hours under nitrogen atmosphere K ₂ CO ₃ (0.280 g, 2.02 mmol), diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (1; 0.104 g, 0.5 mmol), 4-bromoanisole (0.386 g, 2.0 mmol), Pd (OAc) ₂ (0.0116 g, 0.052 mmol), PPh ₃ (0.0286 g, 0.11 mmol) and DMF (2.5 mL) were added, and the mixture was stirred at 140 ° C. for 48 hours. After cooling to room temperature, the mixture was filtered using celite. To the filtrate was added saturated brine (5 mL), and the mixture was extracted with chloroform (10 mL × 3). The extract was dried over sodium sulfate. The solvent was removed under reduced pressure, and 3,10-bis (4-methoxyphenyl) diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (5; 0.072 g) was obtained by column chromatography (silica gel, ethyl acetate). , 34%) as a white solid. Recrystallization from a hexane-chloroform mixed solvent gave colorless crystals. Colorless crystals; mp 219.3-220.1 ° C; ¹ H NMR (300 MHz, CDCl ₃ ) δ 3.92 (s, 6H), 7.03-7.06 (m, 2H), 7.05 (d, J = 9.0 Hz, 4H), 7.44 ( s, 2H), 7.46 (d, J = 8.7 Hz, 4H), 7.51-7.54 (m, 2H); IR (KBr / cm ^-1 ) 2840, 1611, 1571, 1505, 1376, 1285, 1249, 1177, 1026, 833, 754, 680, 598. FAB-MS, m / z = 421 ([M + H] ⁺ ).

Example 5
Method for synthesizing compound (15)
Synthesis of 4,4 '-(Diimidazo [1,2-a: 2', 1'-c] quinoxaline-3,10-diyl) dibenzaldehyde (15) 2 in a screw-cap test tube at 150 ° C under nitrogen atmosphere Time-dried K ₂ CO ₃ (0.554 g, 4.0 mmol), diimidazo [1,2-a: 2 ', 1'-c] quinoxaline (1; 0.209 g, 1.0 mmol), 4-bromobenzaldehyde (0.740 g, 4.0 mmol), Pd (OAc) ₂ (0.0223 g, 0.10 mmol), PPh ₃ (0.0578 g, 0.22 mmol) and DMF (5 mL) were added, and the mixture was stirred at 140 ° C. for 48 hours. After cooling to room temperature, the mixture was filtered using celite. To the filtrate was added saturated brine (5 mL), and the mixture was extracted with chloroform (10 mL × 3). The extract was dried over sodium sulfate. The solvent was distilled off under reduced pressure, and 4,4 '-(diimidazo [1,2-a: 2' was obtained by column chromatography (silica gel, ethyl acetate) and preparative GPC (JIGEL-1H and 2H linked column, chloroform). , 1'-c] quinoxaline-3,10-diyl) dibenzaldehyde (15; 0.116 g, 47%) was obtained as a yellow solid. Yellow solid; mp 282.2-282.7 ° C; ¹ H NMR (300 MHz, CDCl ₃ ) δ 7.13-7.61 (m, 2H), 7.49-7.52 (m, 2H), 7.63 (s, 2H), 7.77 (d, J = 8.4 Hz, 4H), 8.06 (d, J = 8.4 Hz, 4H), 10.14 (s, 2H).

Examples 6-100
The compounds (3), (6) to (14), (16) to (16) of the present invention described in Tables 1 to 7 were synthesized by the same synthesis method as in Examples 1 to 5 by combining the above reaction formulas 1 to 7. (100) was synthesized. The structure of the obtained compound was confirmed by mass spectrum (manufactured by JEOL Ltd., JMX-AX500 and Thermo Scientific, Exactive), and elemental analysis (Perkin Elmer 2400CHN Element Analyzer). The results of elemental analysis are shown in Tables 8-10. The compound numbers are the same as those in Tables 1 to 7.

Examples of Organic EL Device The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. In the examples, all mixing ratios are weight ratios unless otherwise specified. The vacuum deposition method was performed in a vacuum of 10 ⁻⁶ Torr under conditions without temperature control such as substrate heating and cooling. In the evaluation of the light emission characteristics of the element, the characteristics of an organic EL element having an electrode area of 2 mm × 2 mm were measured. Compound (A) and compound (B) were synthesized according to the method described in Journal of Chemical Society of Japan, Vol. 11, 1540 (1991).

Example 101
PEDOT / PSS (poly (3,4-ethylenedioxy) -2,5-thiophene / polystyrene sulfonic acid, BAYTRON P VP CH8000 manufactured by Bayer) manufactured on a cleaned glass plate with an ITO electrode by a spin coating method A hole injection layer having a thickness of 40 nm was obtained. Next, 60% of PVK (polyvinylcarbazole), 3% of compound (1) and 37% of electron transport material (compound (A)) were dissolved in toluene at a concentration of 2.0 wt%, and 70 nm by spin coating method. A light emitting layer having a film thickness was obtained. Furthermore, after depositing 20 nm of Ca thereon, 200 nm of Al was deposited to form an electrode to obtain an organic EL device. When this device was subjected to an energization test, blue light emission with a maximum light emission luminance of 750 cd / m ² was obtained.
Compound (A)

Example 102
PEDOT / PSS (poly (3,4-ethylenedioxy) -2,5-thiophene / polystyrene sulfonic acid, BAYTRON P VP CH8000 manufactured by Bayer) manufactured on a cleaned glass plate with an ITO electrode by a spin coating method A hole injection layer having a thickness of 40 nm was obtained. Next, 60% of PVK (polyvinylcarbazole), 3% of compound (2), and 37% of electron transport material (compound (B)) were dissolved in toluene at a concentration of 2.0 wt%, and 70 nm by spin coating method. A light emitting layer having a film thickness was obtained. Furthermore, after depositing Ca to 20 nm thereon, Al was deposited to 200 nm to form an electrode to obtain an organic EL device (102). When an energization test was performed on this device, blue light emission with a maximum light emission luminance of 480 cd / m ² was obtained.
Compound (B)

Example 103
PEDOT / PSS (poly (3,4-ethylenedioxy) -2,5-thiophene / polystyrene sulfonic acid, BAYTRON P VP CH8000 manufactured by Bayer) manufactured on a cleaned glass plate with an ITO electrode by a spin coating method A hole injection layer having a thickness of 40 nm was obtained. Next, 60% of PVK (polyvinylcarbazole), 3% of compound (5) and 37% of electron transport material (compound (B)) were dissolved in toluene at a concentration of 2.0 wt%, and 70 nm by spin coating method. A light emitting layer having a film thickness was obtained. Furthermore, after depositing 20 nm of Ca thereon, 200 nm of Al was deposited to form an electrode to obtain an organic EL device (103). When an energization test was performed on this device, blue light emission with a maximum light emission luminance of 850 cd / m ² was obtained. The EL emission spectrum is shown in FIG.

Example 104
Α-NPD was vacuum-deposited on the washed glass plate with an ITO electrode to obtain a 20 nm-thick hole transport layer. Subsequently, the compound (2) of Table 1 was vacuum-deposited and the light emitting layer with a film thickness of 40 nm was obtained. Next, an electron transporting material (compound (C)) was deposited to obtain an electron injection layer having a thickness of 30 nm. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device (104). When an energization test was performed on this element, blue light emission with a maximum light emission luminance of 15000 cd / m ² was obtained. The EL emission spectrum is shown in FIG.

Examples 105-117
Α-NPD was vacuum-deposited on the washed glass plate with an ITO electrode to obtain a 20 nm-thick hole transport layer. Subsequently, the compound shown in Table 3 among the compounds in Table 1 was vacuum-deposited to obtain a light-emitting layer having a thickness of 40 nm. Next, an electron transporting material (compound (C)) was deposited to obtain an electron injection layer having a thickness of 30 nm. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. Table 11 shows the evaluation results of these elements.
Compound (C

Example 118
Α-NPD was vacuum-deposited on the washed glass plate with an ITO electrode to obtain a 20 nm-thick hole transport layer. Next, the compound (2) and the compound (D) in Table 1 were co-evaporated at a composition ratio of 1:50 to obtain a light emitting layer having a thickness of 40 nm. Subsequently, a tris (8-hydroxyquinolinate) aluminum complex was vapor-deposited to obtain an electron injection layer having a thickness of 20 nm. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. When an energization test was performed on this device, blue light emission with a maximum light emission luminance of 24000 cd / m ² was obtained.
Compound (D)

Examples 119-132
Α-NPD was vacuum-deposited on the washed glass plate with an ITO electrode to obtain a 20 nm-thick hole transport layer. Next, of the compounds in Table 1, the compound shown in Table 4 and the compound (D) were co-evaporated at a composition ratio of 1:50 to obtain a light emitting layer having a thickness of 40 nm. Subsequently, tris (8-hydroxyquinolinate) aluminum complex was vapor-deposited to obtain an electron injection layer having a thickness of 30 nm. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. Table 12 shows the evaluation results of these elements.

Example 133
On the washed glass plate with an ITO electrode, α-NPD was vacuum-deposited to obtain a 50 nm-thick hole transport layer. Next, the compound (E) and the compound (11) in Table 1 were co-evaporated at a composition ratio of 1:50 to obtain a light emitting layer having a thickness of 40 nm. Subsequently, tris (8-hydroxyquinolinate) aluminum complex was vapor-deposited to obtain an electron injection layer having a thickness of 30 nm. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. When an energization test was performed on this device, blue light emission with a maximum light emission luminance of 19000 cd / m ² was obtained.
Compound (E)

Examples 134-141
On the washed glass plate with an ITO electrode, α-NPD was vacuum-deposited to obtain a 50 nm-thick hole transport layer. Subsequently, the compound (E) and the compound shown in Table 5 among the compounds shown in Table 1 were co-evaporated at a composition ratio of 1:50 to obtain a light emitting layer having a thickness of 40 nm. Subsequently, tris (8-hydroxyquinolinate) aluminum complex was vapor-deposited to obtain an electron injection layer having a thickness of 30 nm. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. Table 13 shows the evaluation results of these elements.

Example 142
On the washed glass plate with an ITO electrode, the compound (80) in Table 1 was vacuum-deposited to obtain a hole injection layer having a thickness of 60 nm. Next, N, N′-bis (4′-diphenylamino-4-biphenylyl) -N, N′-diphenylbenzidine was vacuum deposited to obtain a 20 nm hole transport layer. Furthermore, a tris (8-hydroxyquinoline) aluminum complex is vacuum-deposited to form an electron-injection type light-emitting layer having a thickness of 60 nm, and then an electrode is formed by first depositing 1 nm of lithium fluoride and then 200 nm of aluminum. Thus, an organic EL element was obtained. When this device was subjected to an energization test, green light emission of a tris (8-hydroxyquinoline) aluminum complex having a maximum light emission luminance of 36000 cd / m ² was obtained.

Example 143
A compound (F) is deposited on a glass plate with an ITO electrode to form a 60 nm-thick hole injection layer, and then the compound (79) in Table 1 is deposited to form a 20 nm-thick hole transport layer. did. Next, a tris (8-hydroxyquinoline) aluminum complex is vapor-deposited to form an electron-injecting light-emitting layer having a thickness of 60 nm, and an electrode is formed thereon by vacuum vapor deposition of 1 nm of lithium fluoride and 200 nm of aluminum. Thus, an organic electroluminescence element was obtained. When this device was subjected to a current test, green light emission of a tris (8-hydroxyquinoline) aluminum complex having a maximum light emission luminance of 30000 cd / m ² was obtained.
Compound (F)

Examples 144-158
A compound (F) is vapor-deposited on a glass plate with an ITO electrode to form a 60 nm-thick hole injection layer, and then the compound shown in Table 6 is vapor-deposited among the compounds shown in Table 1 to form a 20-nm-thick hole. A transport layer was formed. Next, a tris (8-hydroxyquinoline) aluminum complex is vapor-deposited to form an electron-injecting light-emitting layer having a thickness of 60 nm, and an electrode is formed thereon by vacuum vapor deposition of 1 nm of lithium fluoride and 200 nm of aluminum. Thus, an organic electroluminescence element was obtained. Table 14 shows the evaluation results of these elements.

Example 149
Α-NPD was vapor-deposited on a glass plate with an ITO electrode to form a hole injection layer having a thickness of 40 nm. The compound (63) and the compound (G) in Table 1 were co-evaporated at a composition ratio of 9: 1 to form a light emitting layer having a thickness of 25 nm. Further, BCP was deposited to form a 15 nm hole blocking layer. Further, Alq3 was deposited to form an electron injection layer having a thickness of 25 nm. A cathode was formed thereon by vapor deposition of 1 nm of lithium fluoride (LiF) and 100 nm of aluminum (Al) to obtain an organic electroluminescence device. This device showed an external quantum efficiency of 7.1% at a DC voltage of 10V. Further, the half-life when driven at a constant current with an emission luminance of 200 (cd / m ² ) was 1000 hours or more.
Compound (G)

Example 150
Copper phthalocyanine was deposited on a glass plate with an ITO electrode to form a hole injection layer having a thickness of 35 nm. Further, NPD was deposited to form a 20 nm thick hole transport layer. Compound (H) was deposited to form a light emitting layer having a thickness of 35 nm. Furthermore, the compound (1) in Table 1 was deposited to form an electron transport layer having a thickness of 30 nm. An electrode was formed thereon by vacuum deposition of 1 nm of lithium fluoride (LiF) and 200 nm of aluminum (Al) to obtain an organic electroluminescence device. The maximum light emission luminance of this device was 13000 cd / m ² .
Compound (H)

Example 151
On the glass plate with an ITO electrode, α-NPD was deposited to 60 nm to form a hole injection layer. Further, Alq3 was deposited to form a light emitting layer with a thickness of 20 nm. The compound (6) in Table 1 was deposited to form an electron transport layer having a thickness of 30 nm. A cathode was formed thereon by vapor deposition of 1 nm of lithium oxide (Li ₂ O) and 100 nm of aluminum (Al) to obtain an organic electroluminescence device. This device produced Alq3 green light emission with a maximum light emission luminance of 18000 cd / m ² .

Example 152
On the washed glass plate with an ITO electrode, α-NPD was vacuum-deposited to obtain a 50 nm-thick hole transport layer. Subsequently, the compound (H) was vapor-deposited to obtain a light emitting layer having a thickness of 40 nm. Subsequently, the compound (17) of Table 1 was vapor-deposited and the electron injection layer with a film thickness of 30 nm was obtained. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. When an energization test was performed on this element, blue light emission with a maximum light emission luminance of 25000 cd / m ² was obtained.

Examples 153-161
On the washed glass plate with an ITO electrode, α-NPD was vacuum-deposited to obtain a 50 nm-thick hole transport layer. Subsequently, the compound (H) was vapor-deposited to obtain a light emitting layer having a thickness of 40 nm. Subsequently, the compound shown in Table 7 was vapor-deposited among the compounds of Table 1, and the electron injection layer with a film thickness of 30 nm was obtained. Further thereon, LiF was deposited to a thickness of 0.2 nm, and then Al was deposited to form an electrode having a thickness of 150 nm to obtain an organic EL device. Table 15 shows the evaluation results of these elements.

Example 162
Α-NPD was vapor-deposited on a glass plate with an ITO electrode to form a hole injection layer having a thickness of 40 nm. Subsequently, the compound (29) of Table 1 was vapor-deposited and the light emitting layer with a film thickness of 40 nm was formed. Further, the compound (A) was deposited to form a 7 nm hole blocking layer. Further, Alq3 was deposited to form an electron injection layer having a thickness of 15 nm. A cathode was formed thereon by vapor deposition of 1 nm of lithium fluoride (LiF) and 100 nm of aluminum (Al) to obtain an organic electroluminescence device. This device was confirmed to emit blue EL light with a maximum light emission luminance of 21000 (cd / m ² ).
Examples 163 to 168
On the cleaned glass plate with an ITO electrode, α-NPD was deposited to form a hole injection layer having a thickness of 40 nm. Subsequently, the compound shown in Table 8 was vapor-deposited among the compounds of Table 1, and the light emitting layer with a film thickness of 40 nm was formed. Further, Compound (I) was deposited to form a 7 nm hole blocking layer. Further, Alq3 was deposited to form an electron injection layer having a thickness of 15 nm. A cathode was formed thereon by vapor deposition of 1 nm of lithium fluoride (LiF) and 100 nm of aluminum (Al) to obtain an organic electroluminescence device. The evaluation results for these elements are shown in Table 16.
Compound (I)

  As is clear from Examples 101 to 168, the organic EL element using the organic EL element material of the present invention exhibits particularly excellent performance.

Claims (4)

A material for an organic electroluminescence element represented by the following general formula [1].
General formula [1]

[Wherein R ^{1 to} R ⁸ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted Or an unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, a substituted amino group, A substituted silyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, or an arylsulfonyl group is represented. Further, R ^{1 to} R ⁴ , R ^{5 to} R ⁶ , and R ^{7 to} R ⁸ may form a ring by bonding adjacent groups to each other. ] The organic electroluminescent element material according to claim 1, wherein R ⁵ and R ⁶ and / or R ⁷ and R ⁸ are combined to form a ring. The organic electroluminescent element material according to claim 1 or 2 represented by the following general formula [2].
General formula [2]

[Wherein R ^{9 to} R ²⁰ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted monovalent aliphatic hydrocarbon group, a substituted or unsubstituted monovalent aromatic hydrocarbon group, a substituted Or an unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic heterocyclic group, a cyano group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, a substituted amino group, A substituted silyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, or an arylsulfonyl group is represented. R ^{9 to} R ²⁰ may form a ring by bonding adjacent groups to each other. ] An organic electroluminescence device having at least one organic layer including a light emitting layer between a pair of electrodes comprising an anode and a cathode, wherein at least one layer is the material for an organic electroluminescence device according to any one of claims 1 to 3. an organic electroluminescent device comprising a.

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