JP2016124792A - Material for organic electroluminescent element and organic electroluminescent element prepared therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for organic electroluminescent elements having high luminous efficiency.SOLUTION: The present invention provides a compound represented by formula (1). [X is O or S; R-Rare H, an alkyl group or the like; Arand Arare a phenyl group, a biphenyl group or the like; L is 4-10 phenylene groups].SELECTED DRAWING: Figure 1

Description

  The present invention relates to a material for an organic electroluminescent element and an organic electroluminescent element using the same. In particular, the present invention relates to a hole transport material for an organic electroluminescence device having a high luminous efficiency and a long lifetime, and an organic electroluminescence device using the material.

  In recent years, an organic electroluminescence display (Organic Electroluminescence Display) has been actively developed as an image display device. Unlike a liquid crystal display device or the like, an organic EL display device causes a light emitting material containing an organic compound in a light emitting layer to emit light by recombining holes and electrons injected from an anode and a cathode in the light emitting layer. This is a so-called self-luminous display device to be realized.

  Examples of the organic electroluminescence element (organic EL element) include an anode, a hole transport layer disposed on the anode, a light emitting layer disposed on the hole transport layer, an electron transport layer disposed on the light emitting layer, and An organic electroluminescence element composed of a cathode disposed on an electron transport layer is known. Holes are injected from the anode, and the injected holes move through the hole transport layer and are injected into the light emitting layer. On the other hand, electrons are injected from the cathode, and the injected electrons move through the electron transport layer and are injected into the light emitting layer. Excitons are generated in the light emitting layer by recombination of holes and electrons injected into the light emitting layer. An organic electroluminescence element emits light using light generated by radiation deactivation of its excitons. The organic electroluminescence element is not limited to the above-described configuration, and various modifications can be made.

  In applying an organic electroluminescent element to a display device, high efficiency of the organic electroluminescent element is required. In particular, in the blue light-emitting region, it is difficult to say that the driving voltage of the organic electroluminescent element is high and the light emission efficiency is sufficient as compared with the green light-emitting region and the red light-emitting region. In order to achieve high efficiency of the organic electroluminescence device, the hole transport layer has been studied for stabilization, stabilization, and improvement in durability.

  As a hole transport material used for the hole transport layer, various compounds such as aromatic amine compounds are known, but there are problems in light emission efficiency and device lifetime. For example, Patent Document 1 and Patent Document 2 propose amine derivatives substituted with an aryl group or a heteroaryl group as materials advantageous for extending the lifetime of the organic electroluminescence device. However, it is difficult to say that organic electroluminescence devices using these materials have sufficient luminous efficiency and lifetime. Patent Document 3 proposes an aromatic amine compound having 4-dibenzofuran as a charge transport material. However, the molecular weight of the substituent substituted at the amine site is large, and the thermal stability is insufficient, and a layer containing the aromatic amine compound cannot be formed by vapor deposition. Patent Document 4 describes an aromatic amine compound having a dibenzothiophene moiety, but it cannot be said to have sufficient light emission efficiency. Therefore, at present, there is a demand for an organic electroluminescence device having further improved luminous efficiency.

JP 2009-267255 A JP 2009-029726 A JP 2011-051936 A US Patent Application Publication No. 2012/0181521

  This invention solves the above-mentioned problem, Comprising: It aims at providing the organic electroluminescent element material of high luminous efficiency, and an organic electroluminescent element using the same.

  In particular, the present invention relates to a material for an organic electroluminescence device having a high light emission efficiency and a long lifetime, which is used for at least one of the laminated films disposed between the light emitting layer and the anode in the green to blue light emitting region, and the same. An object of the present invention is to provide an organic electroluminescence device using the above.

一般式（１）中、Xは酸素原子又は硫黄原子であり、R₁〜R₄はそれぞれ独立に置換若しくは無置換の環形成炭素数６以上３０以下のアリール基、置換若しくは無置換の環形成炭素数１以上３０以下のヘテロアリール基、炭素数１以上１５以下のアルキル基、シリル基、ハロゲン原子、水素原子又は重水素原子でり、Ar₁及びAr₂はそれぞれ独立に置換若しくは無置換のフェニル基、ビフェニル基、ナフチル基、フェニルナフチル基、ナフチルフェニル基又はフェナントリル基であり、Lは以下の一般式（２）で表わされる置換若しくは無置換の２価基であり、一般式（２）中、nは４以上１０以下の整数である。

According to one embodiment of the present invention, a material for an organic electroluminescence device represented by the following general formula (1) is provided.

In general formula (1), X is an oxygen atom or a sulfur atom, R _{1 to} R ₄ are each independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted ring formation. A heteroaryl group having 1 to 30 carbon atoms, an alkyl group having 1 to 15 carbon atoms, a silyl group, a halogen atom, a hydrogen atom or a deuterium atom, and Ar ₁ and Ar ₂ are independently substituted or unsubstituted. A phenyl group, a biphenyl group, a naphthyl group, a phenylnaphthyl group, a naphthylphenyl group or a phenanthryl group; L is a substituted or unsubstituted divalent group represented by the following general formula (2); N is an integer of 4 or more and 10 or less.

  The material for an organic electroluminescence device according to an embodiment of the present invention includes 4 to 10 phenylene groups as a linking group L between an amine moiety and a dibenzoheteroyl moiety, whereby an amine moiety and a dibenzo group are interposed. By reducing the influence of the conjugated structure with the hetero moiety, the light emission efficiency of the organic electroluminescence element can be improved.

  L in the general formula (1) may include at least one metaphenylene group.

  The material for an organic electroluminescence device according to one embodiment of the present invention maintains the properties of the amine by including at least one metaphenylene group in the linking group L interposed between the amine site and the dibenzoheteroal site. However, since the molecule is polarized by the effect of the oxygen atom of the dibenzofuran moiety or the sulfur atom of the dibenzothiophene moiety, the amorphous property is improved, and further increase in efficiency of the organic electroluminescence element can be achieved.

  According to one embodiment of the present invention, there is provided an organic electroluminescence device comprising at least one layer of any of the above organic electroluminescence device materials.

  The organic electroluminescent device according to an embodiment of the present invention can achieve high luminous efficiency by including at least one of the organic electroluminescent device materials.

  According to one embodiment of the present invention, there is provided an organic electroluminescence device comprising any one of the above-mentioned materials for organic electroluminescence devices in at least one layered film disposed between a light emitting layer and an anode.

  An organic electroluminescent element according to an embodiment of the present invention is high by including any one of the organic electroluminescent element materials in at least one of the laminated films disposed between the light emitting layer and the anode. Luminous efficiency can be realized.

  ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element material which implement | achieves high luminous efficiency, and an organic electroluminescent element using the same can be provided. The material for an organic electroluminescence device of the present invention has 4 or more and 10 or less phenylene groups interposed as a linking group L between an amine moiety and a dibenzoheteroyl moiety, whereby By reducing the influence of the conjugated structure, the light emission efficiency of the organic electroluminescence element can be improved. In particular, a remarkable effect can be obtained in the blue light emitting region.

It is the schematic which shows the organic electroluminescent element 100 which concerns on one Embodiment of this invention. It is the schematic which shows the organic electroluminescent element 200 which concerns on one Embodiment of this invention.

  As a result of intensive studies to solve the above problems, the present inventors have found that the organic electroluminescence device material of the present invention has 4 or more and 10 or less linking groups L between the amine moiety and the dibenzoheteroyl moiety. By interposing the phenylene group, the influence of the conjugated structure of the amine moiety and dibenzoheteroyl moiety is alleviated, increasing the stability of radicals during carrier transport and achieving higher efficiency of organic electroluminescence devices. Found that you can.

  Hereinafter, with reference to drawings, the material for organic electroluminescent elements concerning the present invention and the organic electroluminescent element using the same are explained. However, the organic electroluminescent element material of the present invention and the organic electroluminescent element using the same can be implemented in many different modes, and are limited to the description of the embodiments described below. It is not a thing. Note that in the drawings referred to in this embodiment, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.

The organic electroluminescent element material according to the present invention is an amine compound represented by the following general formula (1).

In the organic electroluminescent device material according to the present invention, in general formula (1), X is an oxygen atom or a sulfur atom, and R _{1 to} R ₄ are each independently a substituted or unsubstituted ring-forming carbon number of 6 or more and 30. The following aryl groups, substituted or unsubstituted ring-forming carbon atoms having 1 to 30 carbon atoms, alkyl groups having 1 to 15 carbon atoms, silyl groups, halogen atoms, hydrogen atoms or deuterium atoms, Ar ₁ And Ar ₂ are each independently a substituted or unsubstituted phenyl group, biphenyl group, naphthyl group, phenylnaphthyl group, naphthylphenyl group or phenanthryl group, and L is a substituted or unsubstituted group represented by the following general formula (2) In general formula (2), n is an integer of 4 or more and 10 or less.

That is, the material for an organic electroluminescence device according to the present invention is an amine compound represented by the following general formula (3).

The aryl group having 6 to 30 ring carbon atoms used for R _{1 to} R ₄ in the general formula (1) includes a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a biphenyl group, a terphenyl group, a quarterphenyl group, Examples include, but are not limited to, a fluorenyl group, a triphenylene group, a biphenylene group, a pyrenyl group, a benzofluoranthenyl group, a chrysenyl group, a phenylnaphthyl group, and a naphthylphenyl group.

The heteroaryl group having 1 to 30 ring carbon atoms used for R _{1 to} R ₄ is pyridyl group, quinolyl group, isoquinolyl group, benzofuryl group, benzothienyl group, indolyl group, benzoxazolyl group, benzothiazolyl group. Group, quinoxalyl group, benzimidazolyl group, dibenzofuryl group, dibenzothienyl group, carbazolyl group and the like, but are not limited thereto.

Examples of the alkyl group having 1 to 15 carbon atoms used for R _{1 to} R ₄ include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, and t-butyl group. N-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2-dihydroxyethyl group 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1,2,3-trichloropropyl Group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group, 1, 2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group, 2,3-diiodo- t-butyl group, 1,2,3-triiodopropyl group, cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group, 2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropyl group 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group, nitromethyl group, 1-nitroethyl group, 2-nitroethyl Group, 2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropyl group, 2,3-dinitro-t-butyl group, 1,2,3-trinitropropyl group, cyclopropyl group, Examples thereof include, but are not limited to, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-norbornyl group, and a 2-norbornyl group.

The silyl group used for R _{1 to} R ₄ may be a trialkylsilyl group, a triarylsilyl group, a monoalkyldiarylsilyl group, a dialkylmonoarylsilyl group, such as a trimethylsilyl group or a triphenylsilyl group. Etc.

Further, examples of the halogen atom used in the R ₁ to R _4, a fluorine atom (F), it may be a chlorine atom (Cl), bromine (Br).

Here, adjacent R _{1 to} R ₄ may be bonded to each other to form a saturated or unsaturated ring.

Ar ₁ and Ar ₂ in the general formula (1) are each independently a substituted or unsubstituted phenyl group, biphenyl group, naphthyl group, phenylnaphthyl group, naphthylphenyl group or phenanthryl group, A biphenyl group is preferred. By applying a biphenyl group to Ar ₁ and / or Ar ₂ , moderate conjugation spread in the molecule can be realized, so that the stability of the material can be improved. In addition, a wide energy gap can be maintained, and a decrease in light emission efficiency can be prevented.

  L in the general formula (1) is a divalent linking group in which 4 or more and 10 or less substituted or unsubstituted phenylene groups are bonded as shown in the general formula (2). That is, the linking group L is a quarter phenylene group, a kink phenylene group, a sexi phenylene group, a septi phenylene group, an oct phenylene group, a nobi phenylene group, or a deciphenylene group. As the substituent of each phenylene group constituting the linking group L, each independently substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, substituted or unsubstituted hetero ring having 1 to 30 ring carbon atoms. Examples thereof include an aryl group, an alkyl group having 1 to 15 carbon atoms, a silyl group, a halogen atom, and a deuterium atom.

An aryl group having 6 to 30 ring carbon atoms, a heteroaryl group having 1 to 30 ring carbon atoms, and a carbon number of 1 to 15 carbon atoms, which are substituents for each phenylene group constituting the linking group L described above. The alkyl group, silyl group, and halogen atom of R _{1 to} R ₄ described above, an aryl group having 6 to 30 ring carbon atoms, a heteroaryl group having 1 to 30 ring carbon atoms, and 1 or more carbon atoms. It may be the same as 15 or less alkyl groups, silyl groups and halogen atoms.

  Here, the number of substituents of each phenylene group constituting the linking group L may be different depending on each phenylene group. In each phenylene group, when a plurality of substituents are substituted with phenylene groups, the respective substituents may be the same as or different from each other. In each phenylene group constituting the linking group L, adjacent substituents may be bonded to form a saturated or unsaturated ring.

  The linking group L in the general formula (1) preferably contains at least one metaphenylene group. That is, at least one of the 4 or more and 10 or less substituted or unsubstituted phenylene groups constituting the linking group L is preferably a metaphenylene group. In particular, the linking group L preferably contains one metaphenylene group.

  Further, when the linking group L in the general formula (1) contains at least one metaphenylene group, the metaphenylene group is preferably not directly bonded to the nitrogen atom (N) or dibenzoheteroyl site of the amine.

  The amine compound which is a material for an organic electroluminescence device of the present invention represented by the general formula (3) shown above is composed of 4 or more and 10 or less phenylene as a linking group L between an amine moiety and a dibenzoheteroyl moiety. By interposing the group, the influence of the conjugated structure between the amine moiety and the dibenzoheteroyl moiety is alleviated. Thereby, the stability of the radical at the time of carrier transport of the amine compound of the present invention is increased, and high efficiency of the organic electroluminescence device using the amine compound can be realized.

  In addition, at least one metaphenylene group is contained in the linking group L in the general formula (1), that is, at least one metaphenylene group is contained in the linking group L interposed between the amine moiety and the dibenzoheteroyl moiety. As a result, while maintaining the characteristics of the amine, the molecule is polarized by the effect of the oxygen atom of the dibenzofuran moiety or the sulfur atom of the dibenzothiophene moiety, thereby improving the amorphous nature and further improving the efficiency of the organic electroluminescence device. Can be achieved.

  The organic electroluminescent element material according to the present invention is a substance represented by the following structural formula as an example.

  The organic electroluminescent element material according to the present invention may be included in at least one of a plurality of organic layers constituting the organic electroluminescent element. In particular, it may be significantly contained in at least one of the laminated films disposed between the light emitting layer and the anode of the organic electroluminescence element.

  As described above, the organic electroluminescent element material according to the present invention includes the amine moiety and the amine moiety by interposing 4 or more and 10 or less phenylene groups as the linking group L between the amine moiety and the dibenzoheteroyl moiety. The influence of the conjugated structure with the dibenzoheteroyl moiety is mitigated. Thereby, the stability of the radical at the time of carrier transport of the organic electroluminescent element material of this invention increases, and the high efficiency of the organic electroluminescent element using this amine compound is realizable. In the organic electroluminescent device material according to the present invention, when at least one metaphenylene group is contained in the linking group L interposed between the amine moiety and the dibenzoheteroyl moiety, the oxygen atom or dibenzothiophene in the dibenzofuran moiety Polarization occurs in the molecule due to the effect of the sulfur atom at the site, which improves the amorphous nature and achieves further increase in efficiency of the organic electroluminescence element.

(Organic electroluminescence device)
The organic electroluminescent element using the organic electroluminescent element material according to the present invention will be described. FIG. 1 is a schematic view showing an organic electroluminescence device 100 according to an embodiment of the present invention. The organic electroluminescence device 100 includes, for example, a substrate 102, an anode 104, a hole injection layer 106, a hole transport layer 108, a light emitting layer 110, an electron transport layer 112, an electron injection layer 114, and a cathode 116. In one embodiment, the organic electroluminescent element material according to the present invention can be used in at least one of the laminated films disposed between the light emitting layer and the anode.

  Here, as an example, the case where the organic electroluminescent element material according to the present invention is used for the hole transport layer 108 will be described.

  The substrate 102 may be a flexible substrate such as a transparent glass substrate or a semiconductor substrate resin made of silicon or the like.

The anode 104 is disposed on the substrate 102 and can be formed using indium tin oxide (In ₂ O ₃ —SnO ₂ : ITO), indium zinc oxide (In ₂ O ₃ —ZnO), or the like. .

  The hole injection layer (HIL) 106 can be formed on the anode 104 with a thickness of 10 nm to 150 nm using a known material. For example, triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate (PPBI), N, N′-diphenyl-N, N′-bis- [4 -(Phenyl-m-tolyl-amino) -phenyl] -biphenyl-4,4'-diamine (DNTPD), phthalocyanine compounds such as copper phthalocyanine, 4,4 ', 4 "-tris (3-methylphenylphenylamino) Triphenylamine (m-MTDATA), N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (NPB), 4,4 ′, 4 ″ -tris {N, N diphenylamino} triphenyl Amine (TDATA), 4,4 ′, 4 ″ -tris (N, N-2-naphthylphenylamino) triphenylamine (2-TNATA), poly Nilin / dodecylbenzenesulfonic acid (PANI / DBSA), poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (PANI / CSA), or Polyaniline / poly (4-styrenesulfonate) (PANI / PSS) may be included.

  The hole transport layer (HTL) 108 is formed on the hole injection layer 106 with a thickness of 10 nm or more and 150 nm or less using the organic electroluminescent element material according to the present invention. The hole transport layer 108 containing the organic electroluminescence element material according to the present invention may be formed by, for example, vacuum deposition.

  In addition, when using the organic electroluminescent element material which concerns on this invention for the host material of the light emitting layer (EL) 110, the positive hole transport layer 108 may be formed using a well-known hole transport material. Known hole transport materials include, for example, carbazole such as 1,1-bis [(di-4-tolylamino) phenyl] cyclohexane (TAPC), N-phenylcarbazole, and polyvinyl carbazole. Derivatives, N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1-biphenyl] -4,4′-diamine (TPD), 4,4 ′, 4 ″ -tris ( N-carbazolyl) triphenylamine (TCTA), N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (NPB), etc. In addition, known hole transport materials and the present The hole transport layer 108 may be formed in combination with the organic electroluminescent element material according to the invention.

The light emitting layer (EL) 110 is formed on the hole transport layer 108 with a thickness of 10 nm to 60 nm using a known host material. Known host materials used for the light emitting layer 110 include, for example, tris (8-quinolinolato) aluminum (Alq ₃ ), 4,4′-N, N′-dicavazole-biphenyl (CBP), poly (n-vinylcarbazole) (PVK), 9,10-di (naphthalen-2-yl) anthracene (ADN), 4,4 ′, 4 ″ -tris (N-carbazolyl) triphenylamine (TCTA), 1,3,5-tris ( N-phenylbenzimidazol-2-yl) benzene (TPBI), 3-tert-butyl-9,10-di (naphth-2-yl) anthracene (TBADN), distyrylarylene (DSA), 4,4′- Bis (9-carbazole) -2,2′-dimethyl-biphenyl (dmCBP).

  The light-emitting layer 110 has a styryl derivative (for example, 1,4-bis [2- (3-N-ethylcarbazoryl) vinyl] benzene (BCzVB), 4- (di-p-tolylamino) -4 ′-[( di-p-tolylamino) styryl] stilbene (DPAVB), N- (4-((E) -2- (6-((E) -4- (diphenylamino) styryl) naphthalene-2-yl) vinyl) phenyl- N-phenylbenzenamine (N-BDAVBi)), perylene and its derivatives (eg 2,5,8,11-Tetra-t-butylperylene (TBPe), pyrene and its derivatives (eg 1,1-dipyrene, 1,4 It may contain a dopant such as -dipyrenylbenzene and 1,4-Bis (N, N-Diphenylamino) pyrene), but is not limited thereto.

The electron transport layer (ETL) 112 has a thickness of 15 nm or more and 50 nm or less on the light-emitting layer 110, and includes, for example, a material having Tris (8-hydroxyquinolinato) aluminum (Alq ₃ ) or a nitrogen-containing aromatic ring (for example, 1,3 , 5-tri [(3-pyridyl) -phen-3-yl] benzene-containing materials such as 2,4,6-tris (3 '-(pyridine-3-yl) biphenyl-3-yl) A material containing a triazine ring such as 1,3,5-triazine and a material containing an imidazole derivative such as 2- (4-N-phenylbenzoimidazolyl-1-ylphenyl) -9,10-dinaphthylanthracene).

  The electron injection layer (EIL) 114 has a thickness of 0.3 nm to 9 nm on the electron transport layer 112 and is formed of a material containing, for example, lithium fluoride (LiF), lithium-8-quinolinate (Liq), or the like. .

The cathode 116 is disposed on the electron injection layer 114 and is made of a metal such as aluminum (Al), silver (Ag), lithium (Li), magnesium (Mg), calcium (Ca), a mixture thereof, and an oxide. It is formed of a transparent material such as indium tin (ITO) and indium zinc oxide (In ₂ O ₃ —ZnO).

  Each electrode and each layer constituting the organic electroluminescence element according to the present invention described above can be formed by selecting an appropriate film formation method according to the material such as vacuum deposition, sputtering, and various coatings.

  In the organic electroluminescent element 100 according to the present invention, a hole transport layer capable of realizing high efficiency of the organic electroluminescent element can be formed by using the organic electroluminescent element material according to the present invention described above. it can.

  Moreover, in the organic electroluminescent element 100 which concerns on this invention, the organic electroluminescent element material which concerns on this invention mentioned above may be used as a material of a positive hole injection layer. As described above, the organic electroluminescent element material according to the present invention includes at least one of a plurality of organic layers constituting the organic electroluminescent element, thereby realizing high efficiency of the organic electroluminescent element. be able to.

  The material for an organic electroluminescence element according to the present invention can also be applied to an active matrix organic electroluminescence light emitting device using a TFT.

(Production method)
The organic electroluminescent element material according to the present invention can be synthesized, for example, as follows.

Method for synthesizing compound 5

(Synthesis of Compound A)
Under Ar atmosphere, 62.4 g of N, N-di ([1,1'-biphenyl] -4-yl) -4'-bromo- [1,1'-biphenyl] -4-amine in a 2 L flask, Pd (dppf) Cl ₂ · CH ₂ Cl ₂ (6.46 g), KOAc (33.3 g), and Bis (pinacolato) diboron (33.0 g) were added, and the mixture was stirred at 100 ° C. for 12 hours after vacuum degassing in 750 mL of Dioxane solvent. Thereafter, the solvent was distilled off, CH ₂ Cl ₂ and water were added, the organic phase was separated, magnesium sulfate and activated clay were added, and suction filtration was performed to distill off the solvent. The obtained crude product was purified by silica gel chromatography (using a mixed solvent of dichloromethane and hexane) to obtain 66.4 g (yield 98%) of Compound A as a white solid. The molecular weight of the target product measured by FAB-MS measurement was 599, the chemical formula was estimated to be C ₄₂ H ₃₈ BNO _2, and it was confirmed that the target product was Compound A.

(Synthesis of Compound B)
Next, in an Ar atmosphere, in a 300 mL three-necked flask, 10.0 g of the obtained compound A, 7.6 g of 3-bromo-4′-iodo-1,1′-biphenyl, and 41.54 Pd (PPh ₃ ). g and 5.25 g of potassium carbonate were added, and the mixture was heated and stirred at 90 ° C. for 8 hours in a mixed solvent of 450 mL of toluene and 60 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The resulting crude product is purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane) and then recrystallized with a mixed solvent of toluene / hexane to obtain 9.99 g of Compound B as a white solid (yield 85%). Obtained. The molecular weight of the target product measured by FAB-MS measurement was 703, the chemical formula was estimated to be C ₄₈ H ₃₄ BrN, and it was confirmed that the target product was Compound B.

(Synthesis of Compound 5)
Next, in an Ar atmosphere, a 500 mL three-necked flask was charged with 3.95 g of the obtained compound B, 1.2 g of dibenzofuran-4-boronic acid, 0.84 g of Pd (PPh ₃ ) ₄ and 2.35 g of potassium carbonate. In addition, the mixture was heated and stirred at 90 ° C. for 8 hours in a mixed solvent of 170 mL of toluene and 80 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane), and then recrystallized with a mixed solvent of toluene / hexane to obtain 3.76 g of Compound 5 as a white solid (yield 84%). Obtained. The molecular weight of the target product measured by FAB-MS measurement was 791, the chemical formula was estimated to be C ₆₀ H ₄₁ NO, and it was confirmed that the target product was Compound 5.

  Moreover, the organic electroluminescent element material which concerns on this invention is compoundable as follows, for example.

Synthesis of compound 9

(Synthesis of Compound C)
In an Ar atmosphere, a 300 mL three-necked flask was charged with 10.0 g of Compound A obtained by the above method, 6.0 g of 1-bromo-3-iodobenzene, 1.54 g of Pd (PPh ₃ ) ₄ and potassium carbonate. 5.25 g was added, and the mixture was stirred with heating at 90 ° C. for 8 hours in a mixed solvent of 450 mL of toluene and 60 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The resulting crude product is purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane), and then recrystallized with a mixed solvent of toluene / hexane to give 9.2 g of Compound C as a white solid (88% yield). Obtained. The molecular weight of the target product measured by FAB-MS measurement was 627, the chemical formula was estimated to be C ₄₂ H ₃₀ BrN, and it was confirmed that the target product was Compound C.

(Synthesis of Compound 9)
Next, 3.95 g of the obtained compound C, 1.8 g of (4- (dibenzo [b, d] furan-4-yl) phenyl) boronic acid, Pd ( PPh ₃ ) ₄ (0.84 g) and potassium carbonate (2.35 g) were added, and the mixture was heated and stirred at 90 ° C. for 8 hours in a mixed solvent of 170 mL toluene and 80 mL water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The resulting crude product was purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane), and then recrystallized with a mixed solvent of toluene / hexane to give 4.28 g (yield 86%) of Compound 9 as a white solid. Obtained. The molecular weight of the target product measured by FAB-MS measurement was 791, the chemical formula was estimated to be C ₆₀ H ₄₁ NO, and it was confirmed that the target product was Compound 9.

  Moreover, the organic electroluminescent element material which concerns on this invention is compoundable as follows, for example.

Synthesis of compound 6

In an Ar atmosphere, a 500 mL three-necked flask was charged with 5.00 g of compound B obtained by the above-described method, 1.50 g of dibenzofuran-3-boronic acid, 1.06 g of Pd (PPh ₃ ) ₄ and 2.97 of potassium carbonate. g was added, and the mixture was heated and stirred at 90 ° C. for 8 hours in a mixed solvent of 215 mL of toluene and 101 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The obtained crude product is purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane) and then recrystallized with a mixed solvent of toluene / hexane to obtain 4.86 g (yield 86%) of Compound 6 as a white solid. Obtained. The molecular weight of the target product measured by FAB-MS measurement was 791, the chemical formula was estimated to be C ₆₀ H ₄₁ NO, and it was confirmed that the target product was Compound 6.

  Moreover, the organic electroluminescent element material which concerns on this invention is compoundable as follows, for example.

Synthesis of Compound 49 A white solid compound by the same synthesis and purification method as Compound 5 except that dibenzofuran-4-boronic acid used in the synthesis of Compound 5 was changed to dibenzothiophene-4-boronic acid. 49 (82% yield) was obtained. The molecular weight of the target product measured by FAB-MS measurement was 807, the chemical formula was estimated to be C ₆₀ H ₄₁ NS, and it was confirmed that the target product was Compound 49.

  Moreover, the organic electroluminescent element material which concerns on this invention is compoundable as follows, for example.

Synthesis of compound 1

(Synthesis of Compound D)
Except that 3-bromo-4'-iodo-1,1'-bipheny used in the synthesis of Compound B described above was changed to 4-bromo-4'-iodo-1,1'-biphenyl, Compound D (yield 85%) was obtained as a white solid by the same synthesis and purification method as the synthesis method. The molecular weight of the target product measured by FAB-MS measurement was 703, the chemical formula was estimated to be C ₄₈ H ₃₄ NBr, and it was confirmed that the target product was Compound D.

(Synthesis of Compound 1)
A white solid compound 1 (yield 81%) was obtained by the same synthesis and purification method as the compound 5 synthesis method except that the compound B used in the synthesis of the compound 5 was changed to the compound D. The molecular weight of the target product measured by FAB-MS measurement was 791, the chemical formula was estimated to be C ₆₀ H ₄₁ NO, and it was confirmed that the target product was Compound 1.

  Moreover, the organic electroluminescent element material which concerns on this invention is compoundable as follows, for example.

Synthesis of Compound 29

(Synthesis of Compound E)
N, N-di ([1,1′-biphenyl] -4-yl) -4′-bromo- [1,1′-biphenyl] -4-amine used in the synthesis of Compound A described above is replaced with N, N. Compound except for -di ([1,1'-biphenyl] -4-yl) -4 ''-bromo- [1,1 ': 4', 1 ''-terphenyl] -4-amine Compound E (93% yield) was obtained as a white solid by the same synthesis and purification method as the synthesis method of A. The molecular weight of the target product measured by FAB-MS measurement was 675, the chemical formula was estimated to be C ₄₈ H ₄₂ BNO _2, and it was confirmed that the target product was Compound E.

(Synthesis of Compound F)
Next, under Ar atmosphere, add 10.0 g of 1,3,5-tribromobenzene, 7.80 g of phenyl boronic acid, 9.54 g of Pd (PPh ₃ ) ₄ and 20.4 g of sodium carbonate to a 1 L three-necked flask. The mixture was heated and stirred at 90 ° C. for 8 hours in a mixed solvent of 430 mL of toluene and 210 mL of water. After air cooling, water was added to separate the organic layer, and the solvent was distilled off. The resulting crude product is purified by silica gel column chromatography (using a mixed solvent of dichloromethane and hexane) and then recrystallized with a mixed solvent of toluene / hexane to obtain 5.45 g of Compound F as a white solid (yield 55%). Obtained. The molecular weight of the target product measured by FAB-MS measurement was 310, the chemical formula was estimated as C ₁₂ H ₈ Br _2, and it was confirmed that the target product was Compound F.

(Synthesis of Compound G)
A white solid was synthesized by the same synthesis and purification method as that for Compound C except that Compound A used in the synthesis of Compound C was changed to Compound E and 1-bromo-3-iodobenzene was changed to Compound F. Compound E (yield 64%) was obtained. The molecular weight of the target product measured by FAB-MS measurement was 779, the chemical formula was estimated to be C ₅₄ H ₃₈ BrN, and it was confirmed that the target product was Compound G.

(Synthesis of Compound 29)
Compound 29 (yield 82%) was obtained as a white solid by the same synthesis and purification method as the synthesis method of Compound 5, except that Compound B used in the synthesis of Compound 5 was changed to Compound G. The molecular weight of the target product measured by FAB-MS measurement was 867, the chemical formula was estimated to be C ₆₆ H ₄₅ NO, and it was confirmed that the target product was Compound 29.

Using the above-described compound 1, compound 5, compound 49, compound 6, compound 9, and compound 29 as hole transport materials, organic electroluminescence devices of Examples 1 to 6 were produced by the production method described above.

Moreover, the organic electroluminescent element of the comparative examples 1 thru | or 4 was produced as a comparative example using the comparative example compounds C1-C4 shown below as a hole transport material.

An organic electroluminescence device 200 according to this example is shown in FIG. In this embodiment, a transparent glass substrate is used as the substrate 202, the anode 204 is formed from ITO having a thickness of 150 nm, the hole injection layer 206 is formed from 2-TNATA having a thickness of 60 nm, and a film having a thickness of 30 nm is formed. A thick hole transport layer 208 is formed, a light emitting layer 210 with a thickness of 25 nm is formed by doping ADN with 3% TBP, an electron transport layer 212 with a thickness of 25 nm is formed with Alq ₃ , and 1 nm is formed with LiF. An electron injection layer 214 having a thickness of 10 nm was formed, and a cathode 216 having a thickness of 100 nm was formed of Al.

The produced organic electroluminescence element 200 was evaluated for light emission efficiency. The luminous efficiency is a value at a current density of 10 mA / cm ² . A C9920-11 luminance alignment characteristic measuring device manufactured by Hamamatsu Photonics was used for measuring the luminous efficiency. Table 1 shows the evaluation results in which the luminous efficiency value of Comparative Example 1 is set to “1.00” and the luminous efficiencies of other Examples and Comparative Examples are expressed as a ratio with Comparative Example 1.

Referring to the results in Table 1, in Examples 1 to 6, in the hole-transporting amine compound having a dibenzoheteroyl moiety, 4 to 10 linking groups L between the amine moiety and the dibenzoheteroyl moiety. By interposing the following phenylene group, the influence of the conjugated structure of the amine moiety and the dibenzoheteroyl moiety is alleviated, and the stability of the radical during carrier transport of the amine compound is increased. It was confirmed that the luminous efficiency was improved as compared with that. Moreover, in the organic electroluminescent element material of the present invention, Example 1 using a compound containing no metaphenylene group as the linking group L, and Example 2 and Example using a compound containing the metaphenylene group as the linking group L In comparison with Example 5, Example 2 and Example 5 show higher luminous efficiency than Example 1. The effect of the oxygen atom of the dibenzofuran moiety or the sulfur atom of the dibenzothiophene moiety while maintaining the properties of the amine by including at least one metaphenylene group in the linking group L interposed between the amine moiety and the dibenzoheteroyl moiety It is considered that higher luminous efficiency is exhibited by improving the amorphous property by causing polarization in the molecule. Further, Example 2 using a compound in which the metaphenylene group contained in the linking group L is directly bonded to the dibenzofuran moiety and the metaphenylene group contained in the linking group L are directly attached to the dibenzofuran moiety and the nitrogen atom (N) of the amine. When compared with Example 5 using the unbonded compound, it was confirmed that Example 5 was improved in luminous efficiency as compared with Example 2. In Examples 1 to 6, by applying a biphenyl group to Ar ₁ and Ar ₂ in the general formula (1) representing the material for an organic electroluminescence device according to the present invention, an appropriate intramolecular conjugation spread is achieved. Since this can be realized, the stability of the material is improved and a wide energy gap can be maintained, which shows high luminous efficiency.

  In Comparative Example 2 and Comparative Example 4, since the dibenzofuran moiety or dibenzothiophene moiety and the amine moiety have a structure conjugated via a p-biphenylene group, the molecule easily takes a planar structure and the amorphous property is impaired. It is considered that the luminous efficiency was lowered. In Comparative Example 1 and Comparative Example 3, it is considered that by introducing a terphenyl group into the amine, the energy gap is reduced and the efficiency is lowered.

  From the results of Table 1, it was confirmed that when the organic electroluminescence device material of the present invention was used as a hole transport material, it showed higher efficiency than the compound of the comparative example. The material for an organic electroluminescence device of the present invention has 4 or more and 10 or less phenylene groups interposed as a linking group L between an amine moiety and a dibenzoheteroyl moiety, whereby the amine moiety and the dibenzoheteroyl moiety. It can be seen that high luminous efficiency is realized by reducing the influence of the conjugated structure and increasing the radical stability during carrier transport of the amine compound.

  The organic electroluminescent element material according to the present invention includes an amine moiety and a dibenzoheteroyl moiety by interposing 4 or more and 10 or less phenylene groups as a linking group L between the amine moiety and the dibenzoheteroyl moiety. The influence of the conjugated structure is mitigated. Therefore, high luminous efficiency of the organic electroluminescence element can be realized. In addition, since the organic electroluminescent element material which concerns on this invention has a wide energy gap, it is also possible to apply to a red area | region and a green area | region.

100 organic EL device, 102 substrate, 104 anode, 106 hole injection layer, 108 hole transport layer, 110 light emitting layer, 112 electron transport layer, 114 electron injection layer, 116 cathode, 200 organic EL device, 202 substrate, 204 anode 206 hole injection layer, 208 hole transport layer, 210 light emitting layer, 212 electron transport layer, 214 electron injection layer, 216 cathode

Claims (4)

The material for organic electroluminescent elements represented by the following general formula (1).

[In General Formula (1), X is an oxygen atom or a sulfur atom, and R _{1 to} R ₄ are each independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted ring. A heteroaryl group having 1 to 30 carbon atoms, an alkyl group having 1 to 15 carbon atoms, a silyl group, a halogen atom, a hydrogen atom or a deuterium atom, and Ar ₁ and Ar ₂ are each independently substituted or unsubstituted A phenyl group, a biphenyl group, a naphthyl group, a phenylnaphthyl group, a naphthylphenyl group, or a phenanthryl group, and L is a substituted or unsubstituted divalent group represented by the following general formula (2). ), N is an integer from 4 to 10.

]   2. The organic electroluminescent element material according to claim 1, wherein L includes at least one metaphenylene group.   The organic electroluminescent element which contains the organic electroluminescent element material of Claim 1 or 2 in at least one layer.   The organic electroluminescent element which contains the organic electroluminescent element material of Claim 1 or 2 in at least one layer of the laminated films arrange | positioned between the light emitting layer and the anode.

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