JP2012056953A - Compound having oxadiazole ring structure substituted with pyridyl group and organic electroluminescent device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic compound having characteristics with excellent electron injection and transportation performances, a hole blocking ability and high stability in a thin-film state as a material for an organic EL (Electroluminescent) device having high efficiency and high durability, and to provide an organic EL device having high efficiency and high durability by using the above compound.SOLUTION: The compound is represented by general formula (1), and the organic electroluminescent (EL) device includes the compound. In the formula, Ar represents an aromatic hydrocarbon group or the like; among Rto R, one out of Rto Rand two out of Rto Rrepresent linking groups, while the others are the same or different from one another and represent a hydrogen atom or the like; m represents an integer of 1 to 3; and n represents an integer of 0 to 4. When n is 0, four out of Rto Rexcluding the linking group cannot be hydrogen atoms at the same time.

Description

  The present invention relates to a compound and an element suitable for an organic electroluminescence (EL) element which is a self-luminous element suitable for various display devices, and more specifically, an oxadiazole ring structure in which a substituted pyridyl group is linked. And an organic EL device using the compound.

Since organic EL elements are self-luminous elements, they have been actively researched because they are brighter and more visible than liquid crystal elements and can be clearly displayed.
In 1987, Eastman Kodak's C.I. W. Tang et al. Have developed an organic EL element using an organic material by developing a two-layer type laminated structure element. They laminate a phosphor that transports electrons and an organic substance that transports holes, and inject both charges into the phosphor layer to emit light, so that they can emit 1000 cd / m ² or more at a voltage of 10 V or less. High brightness can be obtained (see, for example, Patent Document 1 and Patent Document 2).
Up to now, many improvements have been made for practical use of organic EL devices, and the role of the two layers is further subdivided, and sequentially on the substrate, anode, hole injection layer, hole transport layer, light emitting layer, electron High efficiency and durability are achieved by an electroluminescent device provided with a transport layer, an electron injection layer, and a cathode (see, for example, Non-Patent Document 1).
Further, the use of triplet excitons has been attempted for the purpose of further improving the luminous efficiency, and the use of phosphorescent emitters has been studied (for example, see Non-Patent Document 2).

The light emitting layer can also be formed by doping a charge transporting compound generally called a host material with a phosphor or a phosphorescent material. As described in the above seminar proceedings collection, the selection of an organic material in an organic EL element greatly affects various characteristics such as efficiency and durability of the element.
In the organic EL element, the light injected from both electrodes is recombined in the light emitting layer to obtain light emission. However, since the hole moving speed is faster than the electron moving speed, some of the holes pass through the light emitting layer. There is a problem of efficiency reduction due to passing through. Therefore, an electron transport material having a high electron moving speed is demanded.
Tris (8-hydroxyquinoline) aluminum (hereinafter abbreviated as Alq), which is a typical light emitting material, is generally used as an electron transporting material, but is said to have a low electron moving speed. Therefore, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (hereinafter abbreviated as PBD) has been proposed as a material having a high moving speed. (For example, refer nonpatent literature 3).
However, it is pointed out that PBD is poor in stability in a thin film state, such as being easily crystallized, and various oxadiazole derivatives have been proposed (see, for example, Patent Documents 3 to 5).

In these electron transport materials, the stability compared with PBD is improved, but it is still not sufficient, and the electron transfer rate is still insufficient from the viewpoint of balance with the hole transfer rate. . For this reason, Alq having good stability was often used as an electron transport material, but satisfactory device characteristics were not obtained.
In addition, there is a method of inserting a hole blocking layer as a measure for preventing a part of holes from passing through the light emitting layer and improving the probability of charge recombination in the light emitting layer. As a hole blocking material, triazole derivatives (for example, see Patent Document 6), bathocuproine (hereinafter abbreviated as BCP), aluminum mixed ligand complex (BAlq) (for example, see Non-Patent Document 2). Etc. have been proposed.
However, any of the materials has insufficient film stability or insufficient function of blocking holes. Although the hole blocking material generally used at present is BCP, it cannot be said that it is a sufficiently stable material, so it cannot be said that it functions sufficiently as a hole blocking layer, and has satisfactory device characteristics. It was not obtained.
In order to improve the device characteristics of an organic EL device, an organic compound having excellent electron injection / transport performance and hole blocking capability and high stability in a thin film state is required.

JP-A-8-48656 Japanese Patent No. 3194657 Japanese Patent No. 2721442 Japanese Patent No. 3316236 Japanese Patent No. 3486994 Japanese Patent No. 2734341

Proceedings of the 9th meeting of the Japan Society of Applied Physics 55-61 pages (2001) Proceedings of the 9th Workshop of the Japan Society of Applied Physics 23-31 pages (2001) Jpn. J. et al. Appl. Phys. , 27, L269 (1988)

The object of the present invention is as a material for an organic EL device having high efficiency and high durability, having excellent electron injection / transport performance, hole blocking ability, and excellent stability in a thin film state. It is in providing the organic compound which has.
Another object of the present invention is to provide a highly efficient and highly durable organic EL device using the above compound.
The physical characteristics of the organic compound suitable for the present invention are as follows: (1) good electron injectability, (2) fast electron transfer speed, (3) excellent hole blocking ability, (4 ) It can be mentioned that the thin film state is stable. The physical characteristics of the element suitable for the present invention include (1) high luminous efficiency, (2) low emission starting voltage, (3) low practical driving voltage, and (4) maximum light emission. It can be mentioned that the brightness is high.

Therefore, in order to achieve the above-mentioned object, the present inventors pay attention to the fact that the nitrogen atom of the pyridine ring, which is electron-affinity, has the ability to coordinate with the metal. As a result of designing and chemically synthesizing a novel organic compound linked to a diazole ring, trial production of various organic EL devices using the compound, and diligent evaluation of device characteristics, the present invention was completed. .
That is, the above object has been achieved by providing the following compounds.

(1) A compound represented by the following general formula (1) having an oxadiazole ring structure in which substituted pyridyl groups are linked.

(In the formula, Ar represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group; R ₁ , R ₂ , R ₃ , R ₄ and R ₅ , one of them is a linking group, and the other may be the same or different, and may be a hydrogen atom, a fluorine atom, a cyano group, an alkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted group. Represents a substituted naphthyl group, and R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ are two of them being a linking group, and the others may be the same or different, and may be a hydrogen atom, a fluorine atom, a cyano group , An alkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, m represents an integer of 1 to 3, and n represents an integer of 0 to 4. However, when n = 0, _{R 1, R 2, R 3} , R 4 you Four groups excluding the linking group from the fine R ₅ shall not simultaneously hydrogen atoms.)

(2) The compound having an oxadiazole ring structure according to (1), wherein n = 1 in the general formula (1).
(3) The compound having an oxadiazole ring structure according to (1), wherein n = 2 in the general formula (1).
(4) In the above general formula (1), n = 0, and one of the four groups obtained by removing the bonding group from R ₁ , R ₂ , R ₃ , R ₄ and R ₅ is a phenyl group ( 1) The compound which has an oxadiazole ring structure as described.

  The present invention also provides an organic electroluminescence device comprising a pair of electrodes and at least one organic layer sandwiched between them, and containing the above compound as a constituent material of at least one organic layer.

Aromatic carbonization of a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group or a substituted or unsubstituted condensed polycyclic aromatic group represented by Ar in the general formula (1) Specific examples of the hydrogen group, aromatic heterocyclic group or condensed polycyclic aromatic group include phenyl group, biphenyl group, terphenyl group, tetrakisphenyl group, styryl group, naphthyl group, anthryl group, acenaphthenyl group, fluorenyl group. Group, phenanthryl group, indenyl group, pyrenyl group, pyridyl group, pyrimidyl group, furanyl group, pyronyl group, thiophenyl group, quinolyl group, benzofuranyl group, benzothiophenyl group, indolyl group, carbazolyl group, benzoxazolyl group, quinoxalyl Group, benzimidazolyl group, pyrazolyl group, dibenzofuranyl group, dibenzothiophenyl And the like.
As a substituent of a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group or a substituted or unsubstituted condensed polycyclic aromatic group represented by Ar in the general formula (1) Specifically, fluorine atom, chlorine atom, cyano group, hydroxyl group, nitro group, alkyl group, alkoxy group, amino group, substituted amino group, trifluoromethyl group, phenyl group, tolyl group, naphthyl group, aralkyl group Etc.

Specific examples of the substituted pyridyl group in the general formula (1) include a dipyridyl group, a terpyridyl group, and a phenylpyridyl group.
The compound represented by the general formula (1) of the present invention and having an oxadiazole ring structure in which a substituted pyridyl group is linked has a faster electron transfer than a conventional electron transport material and has an excellent hole blocking ability. And the thin film state is stable.
The compound represented by the general formula (1) of the present invention and having an oxadiazole ring structure in which a substituted pyridyl group is linked can be used as a constituent material of an electron transport layer of an organic EL device. By using a material having a higher electron injection / movement speed than conventional materials, the electron transport efficiency from the electron transport layer to the light emitting layer is improved, the light emission efficiency is improved, and the driving voltage is lowered, It has the effect | action that durability of an organic EL element improves.

The compound represented by the general formula (1) of the present invention and having an oxadiazole ring structure linked with a substituted pyridyl group can also be used as a constituent material of a hole blocking layer of an organic EL device. By using a material with excellent hole-blocking ability and electron transportability compared to conventional materials and high stability in the thin film state, the driving voltage is lowered and current resistance is maintained while having high luminous efficiency. Is improved and the maximum light emission luminance of the organic EL element is improved.
The compound represented by the general formula (1) of the present invention and having an oxadiazole ring structure linked with a substituted pyridyl group can also be used as a constituent material of a light emitting layer of an organic EL device. Compared with conventional materials, the material of the present invention, which has excellent electron transport properties and a wide band gap, is used as a host material for a light emitting layer, and a phosphor or phosphorescent light emitter called a dopant is supported to form a light emitting layer. By using it, the drive voltage is lowered, and an organic EL element with improved luminous efficiency can be realized.

  The organic EL device of the present invention has an oxadiazole ring linked with a substituted pyridyl group, which has faster electron movement than conventional electron transport materials, has excellent hole blocking capability, and is stable in a thin film state. Since a compound having a structure is used, high efficiency and high durability can be realized.

  The present invention is a compound having an oxadiazole ring structure in which substituted pyridyl groups are linked, which is useful as a constituent material of an electron transport layer, a hole blocking layer, or a light emitting layer of an organic EL device. It is the produced organic EL element. According to the present invention, the luminous efficiency and durability of a conventional organic EL device can be remarkably improved.

14 is a diagram showing an EL element configuration of Example 19. FIG. 22 is a diagram showing an EL element configuration of Example 21. FIG. 22 is a diagram showing an EL element configuration of Example 22. FIG. 14 is a diagram showing an EL element configuration of Example 23. FIG. 4 is a graph comparing voltage / current density characteristics of Example 19 and Comparative Example 1. FIG. 10 is a graph comparing voltage / luminance characteristics of Example 19 and Comparative Example 1. FIG. 6 is a graph comparing current density / luminance characteristics of Example 19 and Comparative Example 1. FIG. 6 is a graph comparing current density / current efficiency of Example 19 and Comparative Example 1. FIG. 6 is a graph comparing voltage / current density characteristics of Example 21 and Comparative Example 2. FIG. 10 is a graph comparing the voltage / luminance characteristics of Example 21 and Comparative Example 2. It is the graph which compared the current density / luminance characteristic of Example 21 and Comparative Example 2. FIG. It is the graph which compared the current density / current efficiency of Example 21 and Comparative Example 2.

The compounds having an oxadiazole ring structure in which a substituted pyridyl group of the present invention is linked are novel compounds, and these compounds include, for example, 6- (2H-tetrazol-5-yl) -2,2′- It can be synthesized by condensing bipyridine or the corresponding terpyridine or phenylpyridine with various aromatic acid chlorides.
Specific examples of preferable compounds among the compounds having an oxadiazole ring structure in which the substituted pyridyl groups represented by the general formula (1) are linked are shown below, but the present invention is limited to these compounds. It is not something.

These compounds were purified by column chromatography purification, adsorption purification, solvent recrystallization or crystallization. The compound was identified by NMR analysis. As physical properties, DSC measurement (Tg) and melting point were measured. The melting point is an index of vapor deposition, and the glass transition point (Tg) is an index of stability in a thin film state.
The melting point and glass transition point were measured using a powder and a high-sensitivity differential scanning calorimeter DSC3100S manufactured by Bruker AXS.
The work function was measured using an atmospheric photoelectron spectrometer AC2 manufactured by Riken Keiki Co., Ltd. after a 100 nm thin film was formed on the ITO substrate. The work function is an index of hole blocking ability.

As the structure of the organic EL device of the present invention, a structure comprising an anode, a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and a cathode sequentially on a substrate, or an electron transport Examples thereof include an electron injection layer between the layer and the cathode. In these multilayer structures, several organic layers can be omitted. For example, an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode can be sequentially formed on the substrate.
As an anode of the organic EL element, an electrode material having a large work function such as ITO or gold is used. As the hole injection layer, copper phthalocyanine (hereinafter abbreviated as CuPc), a starburst type triphenylamine derivative, a naphthaleneamine compound, or a coating type material can be used.
For the hole transport layer, N, N′-diphenyl-N, N′-di (m-tolyl) benzidine (hereinafter abbreviated as TPD) or N, N′-diphenyl-N, N′-, which is a benzidine derivative. Di (α-naphthyl) benzidine (hereinafter abbreviated as NPD), various triphenylamine tetramers, and the like can be used. Also, a coating type polymer material such as PEDOT / PSS can be used for the hole injection / transport layer.

In addition to compounds having an oxadiazole ring structure in which substituted pyridyl groups are linked as the light emitting layer, hole blocking layer, and electron transporting layer of the organic EL device of the present invention, aluminum complexes, oxazole derivatives, carbazole derivatives, poly Dialkylfluorene derivatives and the like can be used.
By using conventional light-emitting materials such as aluminum complexes and styryl derivatives in the light-emitting layer, and using compounds having an oxadiazole ring structure linked with substituted pyridyl groups as the hole-blocking layer and electron-transporting layer, high performance An organic EL element can be produced. In addition, a high-performance organic EL device can be produced by adding a dopant which is a phosphor such as quinacridone, coumarin, or rubrene, or a phosphorescent material such as an iridium complex of phenylpyridine as a host material for the light-emitting layer. can do.
Furthermore, a compound having an oxadiazole ring structure to which a substituted pyridyl group is linked can be used as an electron transport layer by stacking or co-depositing a conventional electron transport material.
The organic EL device of the present invention may have an electron injection layer. As the electron injection layer, lithium fluoride or the like can be used. As the cathode, an electrode material having a low work function such as aluminum or an alloy having a lower work function such as aluminum magnesium is used as the electrode material.

  Embodiments of the present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

Example 1
Synthesis of (1,3-bis [2- (2,2′-bipyridin-6-yl) -1,3,4-oxadiazol-5-yl] benzene (hereinafter abbreviated as BpyOXDm) (2) )
0.63 g of 6- (2H-tetrazol-5-yl) -2,2′-bipyridine was dissolved in 10 ml of dehydrated pyridine, and 0.29 g of isophthaloyl dichloride was slowly added. The mixture was heated to 115 ° C. and stirred under reflux for 6 hours. After cooling to room temperature, the reaction solution was poured into water, and the precipitated white solid was taken out by suction filtration and washed with water. After vacuum drying at 80 ° C. for 20 hours, the obtained solid was purified by column chromatography (carrier: silica gel, eluent: chloroform / methanol = 20/1) to obtain 0.62 g of BpyOXDm (81% yield). Obtained. The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 9.071 ppm (1H), 8.639-8.714 ppm (6H), 8.325-8.477 ppm (4H), 8.037 ppm (2H), 7.756-7.854 ppm (3H), 7.330 ppm (2H).

Example 2
Synthesis of (1,4-bis [2- (2,2′-bipyridin-6-yl) -1,3,4-oxadiazol-5-yl] benzene (hereinafter abbreviated as BpyOXDp) (3) )
0.67 g of 6- (2H-tetrazol-5-yl) -2,2′-bipyridine was dissolved in 10 ml of dehydrated pyridine, and 0.32 g of terephthaloyl dichloride was added. The mixture was heated to 110 ° C. and stirred under reflux for 5 hours. After cooling to room temperature, the reaction solution was poured into water, and the precipitated white solid was taken out by suction filtration and washed with water. Vacuum drying at 80 ° C. for 20 hours gave a white crude product. Purification by column chromatography yielded 0.58 g (74% yield) of BpyOXDp. The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 8.736 ppm (2H), 8.640 ppm (4H), 8.463 ppm (3H), 8.260-8.384 ppm (4H), 8.060 ppm (2H), 7.932 ppm (2H), 7.380 ppm ( 1H).

Example 3
Synthesis of (2,6-bis [2- (2,2′-bipyridin-6-yl) -1,3,4-oxadiazol-5-yl] pyridine (hereinafter abbreviated as BpyOXDPy) (4) )
0.50 g of 6- (2H-tetrazol-5-yl) -2,2′-bipyridine was dissolved in 10 ml of dehydrated pyridine, and 0.26 g of 2,6-pyridinedicarbonyl dichloride was added. The mixture was heated to 110 ° C. and stirred for 9 hours under reflux. After cooling to room temperature, the reaction solution was poured into water, and the precipitated white solid was taken out by suction filtration and washed with water. Vacuum drying at 80 ° C. for 20 hours gave a white crude product. Purification by column chromatography yielded 0.12 g (24% yield) of BpyOXDPy. The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 8.005-8.648 ppm (13H), 7.667 ppm (2H), 7.256 (2H).

Example 4
(5-tertiarybutyl (1,3-bis [2- (2,2′-bipyridin-6-yl) -1,3,4-oxadiazol-5-yl) benzene (hereinafter referred to as BpyOXDm (5 tBu) Abbreviated to (5)))
5.00 g of 6- (2H-tetrazol-5-yl) -2,2′-bipyridine was dissolved in 100 ml of pyridine and dehydrated by azeotropic distillation. 5-tertiary butyl isophthaloyl dichloride (3.06 g) was added, and the mixture was heated to 110 ° C. and stirred under reflux for 1 hour. After cooling to room temperature, the reaction solution was poured into water, an aqueous sodium hydroxide solution was added, and the precipitated solid was taken out by suction filtration and washed with water. It dried under reduced pressure at 80 degreeC and obtained 5.46 g (yield 84%) of BpyOXDm (5tBu). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 8.852-8.863 ppm (1H), 8.636-8.723 ppm (6H), 8.489-8.495 ppm (2H), 8.339-8.371 ppm (2H), 8.014-8. 086 ppm (2H), 7.76-7.828 ppm (2H), 7.307-7.357 ppm (2H), 1.526 ppm (9H).

Example 5
(3,5-bis [2- (2,2′-bipyridin-6-yl) -1,3,4-oxadiazol-5-yl] -4′-cyano-1,1′-biphenyl (Abbreviated as CPBO) (synthesis of (6))
1,200 ml of toluene and 200 ml of ethanol from 4.9 g of 3,5-bis [2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazol-5-yl] -1-bromobenzene Then, 1.79 g of 4-cyanophenylboronic acid, 186 mg of tetrakis (triphenylphosphine) palladium and 3.73 g of cesium fluoride were added. The mixture was heated to 75 ° C. and stirred for 20 hours. After cooling to room temperature, the reaction solvent was distilled off under reduced pressure, and 300 ml of chloroform was poured and washed with water. After drying the organic layer with magnesium sulfate, the solvent was distilled off under reduced pressure, and the resulting solid was purified by dispersion washing with toluene-methanol (4: 1) to obtain 3.17 g of CPBO (62% yield). ) The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 9.12 ppm (1H), 8.63-8.74 ppm (8H), 8.39 ppm (2H), 8.08 ppm (2H), 7.78-7.95 ppm (6H), 7.33-7.38 ppm (2H).

Example 6
Synthesis of (2,5-bis [2- (2,2′-bipyridin-6-yl) -1,3,4-oxadiazol-5-yl] thiophene (hereinafter abbreviated as BpyOXDTh) (7) )
5.00 g of 6- (2H-tetrazol-5-yl) -2,2′-bipyridine was dissolved in 100 ml of pyridine and dehydrated by azeotropic distillation. 2.47 g of 2,5-thiophene dicarbonyl dichloride was added, and the mixture was heated to 110 ° C. and stirred under reflux for 1 hour. After cooling to room temperature, the reaction solution was poured into water, an aqueous sodium hydroxide solution was added, and the precipitated solid was taken out by suction filtration and washed with water. It dried under reduced pressure at 70 degreeC and obtained the ocherous crude product. After washing with toluene, drying under reduced pressure was performed at 70 ° C. to obtain 4.62 g of BpyOXDTh (yield 78%). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 8.619-8.733 ppm (6H), 8.307-8.335 ppm (2H), 7.887-8.071 ppm (6H), 7.370-7.411 (2H).

Example 7
(2,6-bis [2- (2,2′-bipyridin-6-yl) -1,3,4-oxadiazol-5-yl] naphthalene (hereinafter referred to as BpyOXD (2,6NP) (8)) Abbreviated)))
5.00 g of 6- (2H-tetrazol-5-yl) -2,2′-bipyridine was dissolved in 100 ml of pyridine and dehydrated by azeotropic distillation. 2.99 g of 2,6-naphthalenedicarbonyl dichloride was added, and the mixture was heated to 110 ° C. and stirred under reflux for 1 hour. After cooling to room temperature, the reaction solution was poured into water, an aqueous sodium hydroxide solution was added, and the precipitated solid was taken out by suction filtration and washed with water. It dried under reduced pressure at 70 degreeC, and obtained 5.41 g (yield 84%) of light grayish brown BpyOXD (2,6NP). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 8.837 ppm (2H), 8.642-8.754 ppm (6H), 8.360-8.452 ppm (4H), 8.205-8.237 ppm (2H), 7.923-8.094 ppm (4H) 7.386-7.430 (2H).

Example 8
(1,3-bis [2- (2,2 ′: 6′2 ″ -terpyridin-6-yl) -1,3,4-oxadiazol-5-yl] benzene (hereinafter abbreviated as TpyOXDm) ) (9) synthesis)
6- (2H-tetrazol-5-yl) -2,2 ′: 2.0 ′ of 6′2 ″ -terpyridine was dissolved in 50 ml of dehydrated pyridine and heated to 120 ° C. to azeotropically dehydrate 30 ml. After cooling to 50 ° C., 0.68 g of isophthaloyl dichloride was added, and the mixture was heated to 110 ° C. and stirred under reflux for 3 hours. After cooling to room temperature, the reaction solution was poured into 200 ml of water, and the precipitated tan solid was taken out by suction filtration and washed with water. After vacuum drying at 80 ° C. for 20 hours, the obtained solid was purified by adsorption purification (carrier: NH silica gel, eluent: chloroform) to obtain 1.53 g (yield 67%) of TpyOXDm. The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 9.12 ppm (1H), 8.85 ppm (2H), 8.62-8.73 ppm (6H), 8.37-8.51 ppm (6H), 7.79-8.12 ppm (7H), 7.35 ppm (2H).

Example 9
(Synthesis of 5-phenyl-2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazole (hereinafter abbreviated as PhpyOXDPh) (10))
2-phenyl-6- (2H-tetrazol-5-yl) pyridine (5.0 g) was dissolved in dehydrated pyridine (125 ml), heated to 120 ° C., and 75 ml was azeotropically dehydrated. After cooling to 50 ° C., 3.17 g of benzoyl chloride was added, and the mixture was heated to 100 ° C. and refluxed with stirring for 2 hours. After cooling to room temperature, the reaction solution was poured into 300 ml of water, adjusted to pH 12 with 20% aqueous sodium hydroxide solution, and stirred for 1 hour. The precipitated yellow solid was taken out by suction filtration and washed with water. After vacuum drying at 70 ° C. for 20 hours, the obtained solid was purified by adsorption purification (carrier: NH silica gel, eluent: chloroform) to obtain 6.11 g of PhpyOXDPh (yield 91%). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 8.23-8.26 ppm (3H), 8.14-8.17 ppm (2H), 7.90-7.99 ppm (2H), 7.48-7.58 ppm (6H).

Example 10
(Synthesis of 1,3-bis [2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazol-5-yl] benzene (hereinafter abbreviated as PhpyOXDm) (11))
2-phenyl-6- (2H-tetrazol-5-yl) pyridine (5.0 g) was dissolved in dehydrated pyridine (125 ml), heated to 120 ° C., and 75 ml was azeotropically dehydrated. After cooling to 50 ° C., 2.28 g of isophthaloyl dichloride was added, heated to 100 ° C., and refluxed with stirring for 1 hour. After cooling to room temperature, the reaction solution was poured into 300 ml of water, adjusted to pH 12 with 20% aqueous sodium hydroxide solution, and stirred for 1 hour. The precipitated brown solid was taken out by suction filtration and washed with water. After drying in vacuo at 70 ° C. for 20 hours, the obtained solid was purified by column chromatography (carrier: NH silica gel, eluent: chloroform) to obtain 4.27 g of PhpyOXDm (yield 73%). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 9.07 ppm (1H), 8.46 ppm (2H), 8.28 ppm (2H), 8.17 ppm (4H), 7.92-8.15 ppm (4H), 7.78 ppm (1H), 7.46- 7.55 ppm (6H).

Example 11
(3,5-bis [2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazol-5-yl] -1,1′-biphenyl (hereinafter abbreviated as PhpyOXDBP) ( 12) Synthesis)
960 ml of toluene and 240 ml of ethanol degassed 2.4 g of 3,5-bis [2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazol-5-yl] -1-bromobenzene Then, 40 ml of 2M potassium carbonate aqueous solution, 144 mg of tetrakis (triphenylphosphine) palladium and 586 mg of phenylboronic acid were added. The mixture was heated to 80 ° C. and stirred for 20 hours. After cooling to room temperature, the reaction solvent was distilled off under reduced pressure, and 300 ml of chloroform was poured and washed with water. After drying the organic layer over magnesium sulfate, the solvent was distilled off under reduced pressure, and the resulting solid was purified by column chromatography (carrier: silica gel, eluent: chloroform) to give 1.86 g of PhpyOXDBP (yield 78 %). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 9.02 ppm (1H), 8.65 ppm (2H), 8.29 ppm (2H), 8.15 ppm (4H), 7.92-8.03 ppm (4H), 7.79 ppm (2H), 7.45- 7.56 ppm (9H).

Example 12
(3,5-bis [2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazol-5-yl] -1,1 ′: 4′1 ″ -terphenyl (Abbreviated as PhpyOXDTP) (13))
1000 ml toluene, 250 ml ethanol degassed 2.5 g 3,5-bis [2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazol-5-yl] -1-bromobenzene Then, 42 ml of 2M potassium carbonate aqueous solution, 145 mg of tetrakis (triphenylphosphine) palladium and 991 mg of 4-biphenylboronic acid were added. The mixture was heated to 80 ° C. and stirred for 20 hours. After cooling to room temperature, the reaction solvent was distilled off under reduced pressure, and 600 ml of chloroform was poured and washed with water. After drying the organic layer with magnesium sulfate, the solvent was distilled off under reduced pressure, and the resulting solid was purified by adsorption purification (carrier: NH silica gel, eluent: chloroform) to give 2.13 g of PhpyOXDTP (yield 76). %). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 9.03 ppm (1H), 8.71 ppm (2H), 8.30 ppm (2H), 8.16 ppm (4H), 7.68-8.03 ppm (10H), 7.40-7.52 ppm (9H).

Example 13
(Synthesis of 2,6-bis [2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazol-5-yl] pyridine (hereinafter abbreviated as PhpyOXDPy) (14))
2-phenyl-6- (2H-tetrazol-5-yl) pyridine (5.0 g) was dissolved in dehydrated pyridine (125 ml), heated to 120 ° C., and 75 ml was azeotropically dehydrated. After cooling to 50 ° C., 2.30 g of 2,6-pyridinedicarbonyl dichloride was added, and the mixture was heated to 100 ° C. and stirred for 2 hours. After cooling to room temperature, the reaction solution was poured into 300 ml of water, adjusted to pH 12 with 20% aqueous sodium hydroxide solution, and stirred for 1 hour. The precipitated dark green black solid was taken out by suction filtration and washed with water. After drying in vacuo at 70 ° C. for 20 hours, the obtained solid was purified by column chromatography (carrier: silica gel, eluent: chloroform) to obtain 3.95 g of PhpyOXDPy (yield 67%). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 8.54 ppm (2H), 8.30 ppm (2H), 8.14-8.20 ppm (5H), 7.94-8.01 ppm (4H), 7.41-7.51 ppm (6H).

Example 14
(Synthesis of 1,4-bis [2- (2-phenylpyridin-6-yl) -1,3,4-oxadiazol-5-yl] benzene (hereinafter abbreviated as PhpyOXDp) (15))
2-phenyl-6- (2H-tetrazol-5-yl) pyridine (5.0 g) was dissolved in dehydrated pyridine (125 ml), heated to 120 ° C., and 75 ml was azeotropically dehydrated. After cooling to 50 ° C., 2.30 g of terephthaloyl dichloride was added, heated to 100 ° C. and stirred for 5 hours. After cooling to room temperature, the reaction solution was poured into 300 ml of water, adjusted to pH 12 with 20% aqueous sodium hydroxide solution, and stirred for 1 hour. The precipitated yellow solid was taken out by suction filtration and washed with water. After drying in vacuo at 70 ° C. for 20 hours, the obtained solid was purified by dispersion washing with a mixed solution of chloroform-methanol to obtain 3.40 g of PhpyOXDp (yield 58%). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 8.45 ppm (4H), 8.29 ppm (2H), 8.16 ppm (4H), 7.93-8.02 ppm (4H), 7.50-7.59 ppm (6H).

Example 15
(1,3-bis [[2- (2′-fluorophenyl) pyridin-6-yl] -1,3,4-oxadiazol-5-yl] benzene (hereinafter abbreviated as FPhpyOXDm) (16) Synthesis)
3.0 g of 2- (2-fluorophenyl) -6- (2H-tetrazol-5-yl) pyridine was dissolved in 125 ml of dehydrated pyridine, heated to 120 ° C., and 75 ml was azeotropically dehydrated. After cooling to 50 ° C., 1.30 g of isophthaloyl dichloride was added, and the mixture was heated to 100 ° C. and stirred for 1 hour. After cooling to room temperature, the reaction solution was poured into 300 ml of water, adjusted to pH 12 with 20% aqueous sodium hydroxide solution, and stirred for 1 hour. The precipitated yellow solid was taken out by suction filtration and washed with water. After vacuum drying at 70 ° C. for 20 hours, the obtained solid was purified by adsorption purification (carrier: NH silica gel, eluent: chloroform) to obtain 2.21 g of FPhpyOXDm (yield 63%). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 9.05 ppm (1H), 8.44 ppm (2H), 8.30 ppm (2H), 8.22 ppm (2H), 7.96-8.05 ppm (4H), 7.77 ppm (1H), 7.16- 7.48 ppm (6H).

Example 16
(1,3-bis [[2- (2 ′, 4′-difluorophenyl) pyridin-6-yl] -1,3,4-oxadiazol-5-yl] benzene (hereinafter abbreviated as DFPhpyOXDm) Synthesis of (17))
3.0 g of 2- (2,4-difluorophenyl) -6- (2H-tetrazol-5-yl) pyridine was dissolved in 125 ml of dehydrated pyridine and heated to 120 ° C. to azeotropically dehydrate 75 ml. After cooling to 50 ° C., 1.20 g of isophthaloyl dichloride was added, and the mixture was heated to 100 ° C. and stirred for 1 hour. After cooling to room temperature, the reaction solution was poured into 300 ml of water, adjusted to pH 12 with 20% aqueous sodium hydroxide solution, and stirred for 1 hour. The precipitated brown solid was taken out by suction filtration and washed with water. After vacuum drying at 70 ° C. for 20 hours, the obtained solid was purified by adsorption purification (carrier: NH silica gel, eluent: chloroform) to obtain 2.79 g of DFPhpyOXDm (yield 81%). The product was identified by NMR analysis. The results of NMR analysis (CDCl3) were as follows. 9.05 ppm (1H), 8.45 ppm (2H), 8.21-8.31 ppm (4H), 7.98-8.01 ppm (4H), 7.79 ppm (1H), 6.92-7.09 ppm (4H).

Example 17
About the compound of this invention, melting | fusing point and the glass transition point were calculated | required with the highly sensitive differential scanning calorimeter (The product made from Bruker AXS, DSC3100S).

Melting point Glass transition point BpyOXDm 243 ° C 106 ° C
BpyOXDPy 253 ° C 114 ° C
BpyOXDm (5tBu) 274 ° C 105 ° C
CPBO 341 ° C 136 ° C
TpyOXDm 276 ° C 119 ° C
PhpyOXDBP 262 ° C 101 ° C
PhpyOXDTP 285 ° C 116 ° C

  The compound of the present invention has a high glass transition point and is stable in a thin film state.

Example 18
Using the compound of the present invention, a deposited film having a film thickness of 100 nm was prepared on an ITO substrate, and the work function was measured with an atmospheric photoelectron spectrometer (AC2 type, manufactured by Riken Keiki Co., Ltd.). All of the compounds of the present invention exceeded the measurement limit 6.2 eV of the measuring apparatus.
Thus, the compound of the present invention has a clearly deeper work function than the hole transport material and has a large hole blocking ability.

Example 19
As shown in FIG. 1, the organic EL element has a hole transport layer 4, a light emitting layer 5, an electron transport layer 7, a cathode (aluminum) on a glass substrate 1 on which an ITO electrode is previously formed as a transparent anode 2. Magnesium electrodes) 9 were deposited in this order. The glass substrate 1 on which ITO with a film thickness of 150 nm was formed was cleaned with an organic solvent, and then the surface was cleaned with oxygen plasma treatment. This was attached in a vacuum vapor deposition machine and depressurized to 0.001 Pa or less.
Subsequently, as the hole transport layer 4, TPD was formed to a thickness of about 50 nm at a deposition rate of 6 nm / min. Next, about 20 nm of Alq was formed as the light emitting layer 5 at a deposition rate of 6 nm / min. On this light emitting layer 5, BpyOXDm (2) of this invention was formed as an electron carrying layer 7 about 30 nm with the vapor deposition rate of 6 nm / min. The vapor deposition so far was continuously performed without breaking the vacuum. Finally, a cathode deposition mask was inserted, and an MgAg alloy was deposited at a ratio of 10: 1 by about 200 nm to form the cathode 9. The prepared element was stored in a vacuum desiccator, and the characteristics were measured at room temperature in the air.

The characteristics of the organic EL device of the present invention formed as described above are the applied voltage at which light emission of 100 cd / m ² is obtained, the light emission luminance when a current of 200 mA / cm ² is loaded, and the light emission defined by the light emission luminance / voltage. Evaluated by efficiency.
As a result of applying a DC voltage to the organic EL element, light emission of 3.7 to 100 cd / m ² was observed. At 7.8 V, a current of 200 mA / cm ² flowed, and a stable green light emission of 11900 cd / m ² was obtained. . The luminous efficiency at this luminance was as high as 6.0 cd / A.

Example 20
In the device shown in FIG. 1, an organic EL device was produced under the same conditions as in Example 19 by replacing the material of the electron transport layer 7 from BpyOXDm (2) to BpyOXDPy (4), and the characteristics thereof were examined. Light emission from 4.0 V to 100 cd / m ² was observed, and at 8.5 V, a current of 200 mA / cm ² flowed, and stable green light emission of 11500 cd / m ² was obtained. The luminous efficiency at this luminance was as high as 5.8 cd / A.

Comparative Example 1
For comparison, the material of the electron transport layer 7 was changed to Alq, and an organic EL element was produced under the same conditions as in Example 19 and the characteristics thereof were examined. That is, about 50 nm of Alq3 was formed at a deposition rate of 6 nm / min as the light emitting and electron transporting layers 5 and 7. Emission from 7.2 V to 100 cd / m ² was observed, and at 13.3 V, a current of 200 mA / cm ² flowed, and a green emission of 9600 cd / m ² was obtained. The luminous efficiency at this luminance was 4.6 cd / A.
As described above, the organic EL device of the present invention is superior in luminous efficiency and can achieve a significant reduction in driving voltage as compared with a device using Alq which is used as a general electron transport material. It was found to be excellent in durability.
In the above comparative test, a clear decrease in the driving voltage is observed, so that the electron transfer speed of the compound of the present invention is predicted to be higher in each stage than Alq which is a conventional electron transport material.

Example 21
An organic EL device as shown in FIG. 2 is formed on a glass substrate 1 on which an ITO electrode is previously formed as a transparent anode 2, and a hole transport layer 4, a light emitting layer 5, a hole blocking layer 6, an electron transport layer. 7 and cathode (aluminum magnesium electrode) 9 were deposited in this order. The glass substrate 1 on which ITO with a film thickness of 150 nm was formed was cleaned with an organic solvent, and then the surface was cleaned with oxygen plasma treatment. This was attached in a vacuum vapor deposition machine and depressurized to 0.001 Pa or less.
Subsequently, as the hole transport layer 4, TPD was formed to a thickness of about 50 nm at a deposition rate of 6 nm / min. Next, about 30 nm of Alq was formed as the light emitting layer 5 at a deposition rate of 6 nm / min. On this light emitting layer 5, BpyOXDm (2) which is this invention was formed as a hole-blocking layer 6 about 20 nm with the vapor deposition rate of 6 nm / min. Furthermore, about 20 nm of Alq was formed as the electron transport layer 7 at a deposition rate of 6 nm / min. The vapor deposition so far was continuously performed without breaking the vacuum. Finally, a cathode deposition mask was inserted, and an MgAg alloy was deposited at a ratio of 10: 1 by about 200 nm to form the cathode 9. The fabricated device was stored in a vacuum desiccator and measured for characteristics at room temperature in the atmosphere.

As a result of applying a DC voltage to the organic EL device of the present invention formed as described above, light emission of 5.7 V to 100 cd / m ² was observed, and at 11.4 V, a current of 200 mA / cm ² flowed, and 11600 cd / m ^2. A stable green emission of ² was obtained. The luminous efficiency at this luminance was as high as 6.0 cd / A. Further, the applied voltage was increased to obtain a maximum luminance of 22050 cd / m ² before breakthrough. Since the measured maximum luminance reflects the electrical stability of the element, it becomes an index of the durability of the organic EL element.

Comparative Example 2
For comparison, an organic EL element was produced under the same conditions as in Example 21 with the material of the hole blocking layer 6 replaced with BCP, and the characteristics thereof were examined. That is, about 20 nm of BCP was formed as the hole blocking layer 6 at a deposition rate of 6 nm / min. Emission from 12.0 V to 100 cd / m ² was observed, and at 19.4 V, a current of 200 mA / cm ² flowed, and green emission of 10900 cd / m ² was obtained. The luminous efficiency at this luminance was 5.3 cd / A. The maximum luminance before breakthrough was 12790 cd / m ² .
Thus, it was found that the organic EL device of the present invention was excellent in durability as compared with a device using BCP which is used as a general hole blocking material. Furthermore, it turned out that it is an organic EL element suitable for high-intensity light emission.

Example 22
An organic EL device as shown in FIG. 3 is formed on a glass substrate 1 on which an ITO electrode is previously formed as a transparent anode 2, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, and a hole blocking layer. The layer 6, the electron transport layer 7, and the cathode (aluminum magnesium electrode) 9 were deposited in this order. The glass substrate 1 on which ITO with a film thickness of 150 nm was formed was cleaned with an organic solvent, and then the surface was cleaned with oxygen plasma treatment. This was attached in a vacuum vapor deposition machine and depressurized to 0.001 Pa or less.
Subsequently, about 15 nm of CuPc was formed as the hole injection layer 3 at a deposition rate of 6 nm / min. On top of this, TPD was formed as a hole transport layer 4 at a deposition rate of 6 nm / min to about 50 nm. The vapor deposition so far was continuously performed without breaking the vacuum. The boat was replaced and the pressure was reduced again, and about 20 nm of Alq was formed on the hole transport layer 4 as the light emitting layer 5 at a deposition rate of 6 nm / min. On this light emitting layer 5, BpyOXDm (2) of the present invention was formed as a hole blocking layer / electron transport layer 6 and 7 with a deposition rate of 6 nm / min to about 30 nm. Finally, the pressure was returned to atmospheric pressure, a cathode vapor deposition mask was inserted, the pressure was reduced again, and an MgAg alloy was evaporated at a ratio of 10: 1 to about 200 nm to form the cathode 9. The fabricated device was stored in a vacuum desiccator and measured for characteristics at room temperature in the air.
As a result of applying a DC voltage to the organic EL device of the present invention formed as described above, green light emission of 3.8 V to 100 cd / m ² was observed. The maximum luminance before breakthrough of this element was 40660 cd / m ² .

Comparative Example 3
For comparison, an organic EL device was produced under the same conditions as in Example 22 by replacing BpyOXDm (2) of the present invention with Alq, and the characteristics thereof were examined. That is, as the light emitting layer / hole blocking layer / electron transport layer 5, 6 and 7, Alq was formed to a thickness of about 50 nm at a deposition rate of 6 nm / min. Green light emission of 7.2 to 100 cd / m ² was observed. The maximum luminance before breakthrough of this element was 14990 cd / m ² .
Thus, it was found that the organic EL device of the present invention is excellent in durability and is an organic EL device suitable for high luminance light emission.

Example 23
An organic EL element as shown in FIG. 4 is formed on a glass substrate 1 on which an ITO electrode is previously formed as a transparent anode 2, and a hole transport layer 4, a light emitting layer 5, an electron transport layer 7, and an electron injection layer 8. The cathode (aluminum electrode) 9 was deposited in this order. The glass substrate 1 on which ITO with a film thickness of 150 nm was formed was cleaned with an organic solvent, and then the surface was cleaned with oxygen plasma treatment. This was attached in a vacuum vapor deposition machine and depressurized to 0.001 Pa or less.
Subsequently, as the hole transport layer 4, NPD was formed at about 50 nm at a deposition rate of 6 nm / min. Next, about 20 nm of Alq was formed as the light emitting layer 5 at a deposition rate of 6 nm / min. On the light-emitting layer 5, CPBO (6) according to the present invention was formed as an electron transport layer 7 with a deposition rate of 6 nm / min to about 30 nm. Furthermore, about 0.5 nm of lithium fluoride was formed as the electron injection layer 8 at a deposition rate of 0.6 nm / min. The vapor deposition so far was continuously performed without breaking the vacuum. Finally, a cathode deposition mask was inserted, and aluminum was deposited by about 200 nm to form the cathode 9. The fabricated device was stored in a vacuum desiccator and measured for characteristics at room temperature in the atmosphere.
As a result of applying a DC voltage to the organic EL element thus formed present invention, light emission of 100 cd / ^{m 2} was observed from 3.5 V, to obtain a stable green emission of 10000 cd / ^{m 2} at 6.5V .

Example 24
In the device shown in FIG. 4, an organic EL device was produced under the same conditions as in Example 23, except that the material of the electron transport layer 7 was changed to PhpyOXDm (11) of the present invention, and the characteristics thereof were examined.
Emission of 100 cd / ^{m 2} was observed from 3.4 V, to obtain a stable green emission of 10000 cd / ^{m 2} at 6.3V.
Example 25
In the device shown in FIG. 4, an organic EL device was prepared under the same conditions as in Example 23, except that the material for the electron transport layer 7 was replaced with FPhpyOXDm (16) of the present invention.
Emission of 100 cd / ^{m 2} was observed from 3.3V, to obtain a stable green emission of 10000 cd / ^{m 2} at 6.5V.

Comparative Example 4
For comparison, the material of the electron transport layer 7 was changed to Alq, and an organic EL element was produced under the same conditions as in Example 23 and the characteristics thereof were examined. That is, about 50 nm of Alq3 was formed at a deposition rate of 6 nm / min as the light emitting and electron transporting layers 5 and 7. Emission of 100 cd / ^{m 2} was observed at 3.9V, emission of 10000 cd / ^{m 2} was obtained at 7.8 V.
In the comparative test using the electron injection material, a decrease in the driving voltage is clearly recognized. Therefore, the electron transfer speed of the compound of the present invention is higher in each stage than Alq which is a conventional electron transport material. It is predicted.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on March 25, 2004 (Japanese Patent Application No. 2004-088909) and a Japanese patent application filed on March 25, 2004 (Japanese Patent Application No. 2004-089277). Incorporated herein by reference.

  The compound having an oxadiazole ring structure in which a substituted pyridyl group of the present invention is connected is excellent as a compound for an organic EL device because it has a good electron injection, a high electron moving speed, and a stable thin film state. ing. By producing an organic EL element using the compound, the driving voltage can be remarkably lowered and the durability can be improved. For example, it has become possible to develop home appliances and lighting.

In addition, the code | symbol in a figure represents the following, respectively.
DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Transparent anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode

Claims (11)

A compound represented by the following general formula (1) having an oxadiazole ring structure in which substituted pyridyl groups are linked.

(In the formula, Ar represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group; R ₁ , R ₂ , R ₃ , R ₄ and R ₅ , one of them is a linking group, and the other may be the same or different, and may be a hydrogen atom, a fluorine atom, a cyano group, an alkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted group. Represents a substituted naphthyl group, and R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ are two of them being a linking group, and the others may be the same or different, and may be a hydrogen atom, a fluorine atom, a cyano group , An alkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, m represents an integer of 1 to 3, and n represents an integer of 0 to 4. However, when n = 0, _{R 1, R 2, R 3} , R 4 you Four groups excluding the linking group from the fine R ₅ shall not simultaneously hydrogen atoms.)   The compound having an oxadiazole ring structure according to claim 1, wherein n = 1 in the general formula (1).   The compound having an oxadiazole ring structure according to claim 1, wherein n = 2 in the general formula (1). 2 in the general formula (1), wherein n = 0, and one of the four groups excluding the binding group from R ₁ , R ₂ , R ₃ , R ₄ and R ₅ is a phenyl group. A compound having an oxadiazole ring structure. In an organic electroluminescence device having a pair of electrodes and at least one organic layer sandwiched between them, a compound having an oxadiazole ring structure represented by the following general formula (1) and linked with a substituted pyridyl group An organic electroluminescence element contained as a constituent material of at least one organic layer.

(In the formula, Ar represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group; R ₁ , R ₂ , R ₃ , R ₄ and R ₅ , one of them is a linking group, and the other may be the same or different, and may be a hydrogen atom, a fluorine atom, a cyano group, an alkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted group. Represents a substituted naphthyl group, and R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ are two of them being a linking group, and the others may be the same or different, and may be a hydrogen atom, a fluorine atom, a cyano group , An alkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, m represents an integer of 1 to 3, and n represents an integer of 0 to 4. However, when n = 0, _{R 1, R 2, R 3} , R 4 you Four groups excluding the linking group from the fine R ₅ shall not simultaneously hydrogen atoms.)   The organic electroluminescent element according to claim 5, wherein n = 1 in the general formula (1).   The organic electroluminescent element according to claim 5, wherein n = 2 in the general formula (1). A n = 0 in the general formula _(1), one of the four groups excluding the linking group from _{R 1, R 2, R 3} , R 4 and _{R 5} is a phenyl group, according to claim 5, wherein Organic electroluminescence device.   The organic electroluminescent element of Claim 5 which contains the compound represented by the said General formula (1) in an electron carrying layer.   The organic electroluminescent element of Claim 5 which contains the compound represented by the said General formula (1) in a hole-blocking layer.   The organic electroluminescent element of Claim 5 which contains the compound represented by the said General formula (1) in a light emitting layer.