JP2001143870A - Phenoxazone compound, diamino naphthol derivative and organic thin film el element using phenoxazone compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic thin film EL device in red color at high brightness the novel phenoxazone compound that can be applied by using red- luminescent dopant, the intermediative that is useful in producing that novel phenoxazone compound and the red-luminescent organic thin film EL device which utilizes that novel phenoxazone compound are realized. SOLUTION: An organic thin film EL device that can be stable in red color at high brightness can be provided by using phenoxazone compound expressed by general formula 1 as a dopant. (Herein, Ar1 and Ar2 are selected independently each other from allyl group).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an organic thin-film EL device using a novel phenoxazone compound, a diaminonaphthol derivative and a phenoxazone compound.

[0002]

2. Description of the Related Art As an organic thin film EL device, an electron transport layer composed of an organic compound is generally laminated between a cathode composed of a metal having a small work function and a transparent anode having a large work function. A hole transport layer composed of an organic compound,
And a three-layer structure in which a hole injection layer made of an organic compound is disposed.

In the organic thin-film EL device having the above structure, the holes injected from the anode and the electrons injected from the cathode recombine near the interface between the electron transport layer and the hole transport layer, and are excited. A child arises. The light emitting material in the electron transporting layer or the hole transporting layer is excited during the process of radiation deactivation of the exciton, and light is emitted to the outside.

There are two types of organic thin-film EL devices that emit light according to the above principle. One is that the hole or electron transport layer itself also functions as a light emitting material. For example, C.I. W. Tang et al.
9-194393, JP-A-63-264692, JP-A-63-295695, Applied
Physics Letter Vol. 51, No. 12, page 913 (1
987), and Journal of Applied Physics, Vol. 65, No. 9, page 3610 (1989). This element comprises indium tin oxide (hereinafter abbreviated as ITO) as an anode, copper phthalocyanine as a hole injection layer, 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane as a hole transport layer, and a light emitting layer. Tris (8-hydroxyquinolinato) aluminum (hereinafter abbreviated as Alq ₃ ) as an electron transporting layer (hereinafter abbreviated as an electron transporting luminescent layer), and MgAg as a cathode
Alloys were used. When a forward DC voltage is applied to the element, green light emission from Alq ₃ is obtained.

[0005] The other is a hole or electron transport layer in which a fluorescent organic material is doped at an appropriate ratio as a light emitting material. For example, Wakimoto et al.
There is a device which has been disclosed in Proceedings of the Annual Meeting of the Society of Polymer Science, Vol. 40, No. 10, page 3600 (1991). The element is
ITO as anode, 4,4 ', 4''as hole injection layer
-Tris (3-methylphenylphenylamino) triphenylamine, N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'- as hole transport layer
Biphenyl-4,4'-diamine, A as an electron transport layer
lq _3, (hereinafter referred to as Qd) 0.5 wt% doped with about quinacridone in Alq ₃ layer in a light-emitting material, AlLi alloy has been used as a cathode. When a forward DC voltage is applied to the device, green light emission from Qd is obtained.

In the element of the former type, the organic material constituting the carrier transport layer also serving as the light emitting layer is required to form not only a fluorescent material but also an amorphous film as the carrier transport material. , And high heat resistance, there are many restrictions on the selection of materials, but in the latter case, it is not necessary to consider the film-forming properties of the organic luminescent material used as a dopant, There is an advantage that a conductive substance can be used as a dopant.

[0007]

In order to emit multi-color light or full-color light, elements that emit light in three primary colors, red, green, and blue, are required. Among them, the red light-emitting element is represented by the formula (5). A device using DCM1 as a dopant, Nile Red represented by the formula (6), and Tetraphenylporphyrin represented by the formula (7) as a dopant is known (Journal of Applied Physics, Vol. 65, No. 9).
No. 3610, JP-A-7-212457, Journal of Applied Physics, Vol. 69, No. 20, page 2959).

[0008]

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[0009]

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[0010]

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Among these, in the organic thin film EL device using the compound represented by the formula (5) or (6) as a dopant, the luminescent color when the dopant concentration is optimized so that the luminous efficiency is maximized is the peak of the EL luminescence. Since the wavelength is about 610 nm, the wavelength is close to orange, and there is a problem that the color balance is reduced even if multicoloring is attempted.

Further, in the organic thin film EL device using the compound represented by the formula (7) as a dopant, the peak wavelength of EL emission is 655 nm and red emission is achieved, but the luminance is as low as 42 cd / m ^2. was there.

The present invention has been made to solve the above problems, and can be applied as a dopant that emits red light in order to realize an organic thin film EL device that emits red light with high luminance. It is an object of the present invention to provide a novel phenoxazone compound, an intermediate useful for producing the novel phenoxazone compound, and an organic thin-film EL device emitting red light, characterized by using the novel phenoxazone compound. .

[0014]

According to the first aspect of the present invention,
The present invention has been made in order to solve the above-mentioned problem, and has been developed in view of the dibenzo [a, j] phenoxazone represented by the formula (8).
A diarylamino group which is an electron donating group at
A phenoxazone compound represented by the general formula (1), which is capable of emitting strong red fluorescence by causing intramolecular charge transfer with a carbonyl group which is an electron-withdrawing group at the position.

[0015]

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[0016]

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Here, Ar ₁ and Ar ₂ are independently selected from aryl groups. Examples of the aryl group include a group having a benzene ring, a naphthalene ring, or an anthracene ring skeleton. These groups may be substituted, and examples of the substituent include a lower alkyl group and a lower alkoxy group. In the present invention, a lower alkyl group means an alkyl group having 1 to 6 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group,
An isopentyl group and the like can be exemplified. Further, the lower alkoxy group means an alkoxy group having 1 to 6 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group,
Examples include an isopropoxy group and a t-butoxy group.

The invention according to claim 2 is the invention according to claim 1, wherein Ar ₁ and Ar ₂ in the phenoxazone compound represented by the general formula (1) have a benzene ring skeleton. It is a phenoxazone compound represented by the formula (2).

[0019]

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Here, R _{1 to} R ₁₀ are independently selected from a hydrogen atom, a lower alkyl group and a lower alkoxy group.

A third aspect of the present invention is directed to producing a phenoxazone compound represented by the above general formula (1) according to the first aspect.
By reacting the compound represented by the formula with 2-hydroxy-1,4-naphthoquinone represented by the formula (9), the phenoxazone compound represented by the formula (1) can be easily produced.

[0022]

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(Here, Ar ₁ and Ar ₂ are each independently selected from an aryl group. R ₁₁ represents a protecting group for an amino group.)

[0024]

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The invention according to claim 4 has been made for producing a phenoxazone compound represented by the general formula (2) according to claim 2, and is represented by the general formula (4) of the invention. The compound is represented by the formula (9):
The phenoxazone compound represented by the general formula (2) can be easily produced by reacting with 1,4-naphthoquinone.

[0026]

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(Wherein, R _{1 to} R ₁₀ are each independently selected from a hydrogen atom, a lower alkyl group, or a lower alkoxy group; and R ₁₁ represents a protecting group for an amino group.)

According to a fifth aspect of the present invention, between a pair of electrodes,
An organic thin film EL device having at least one hole transport layer and an electron transport layer made of an organic compound, wherein at least one phenoxazone compound according to claim 1 or 2 is doped in the hole transport layer or the electron transport layer. An organic thin-film EL device characterized in that:

According to a sixth aspect of the present invention, based on the fifth aspect, the concentration of the phenoxazone compound according to the first or second aspect with respect to the host material in the hole transporting layer or the electron transporting layer is 0.01 to 10% by weight. % Of the organic thin film EL device.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The phenoxazone compound of the present invention is produced, for example, according to the following method.

The compound of the formula (3) or (4) is combined with 1.5 equivalents of 2-hydroxy-1,2 represented by the formula (9).
By heating 4-naphthoquinone in N, N-dimethylformamide (hereinafter abbreviated as DMF) at 80 ° C. for 24 hours in the presence of hydrochloric acid or p-toluenesulfonic acid monohydrate, the general formulas (1) and ( The phenoxazone compound represented by 2) can be easily produced.

The diaminonaphthol derivatives represented by the general formulas (3) and (4), which are intermediates of the phenoxazone compound of the present invention, are also novel compounds and are produced, for example, by the following procedure.

The 1-naphthylamine represented by the formula (10) is p-toluenesulfonylated by heating under reflux for 2 hours in pyridine together with 1.0 equivalent of p-toluenesulfonic acid chloride to give 1-naphthylamine represented by the formula (11). -(p-Toluenesulfonyl) aminonaphthalene is obtained.

[0034]

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[0035]

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(Where Ts represents a p-toluenesulfonyl group)

Next, 1- (p-toluenesulfonyl) aminonaphthalene represented by the formula (11) is reacted with 1.0 equivalent of bromine in DMF at 0 ° C. for 1 hour to form a monobrominated compound. 1-bromo-4- (p-toluenesulfonyl) aminonaphthalene is obtained.

[0038]

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Next, 1-bromo-4- represented by the formula (12)
(p-Toluenesulfonyl) aminonaphthalene was nitrated by reacting it with 1.2 equivalents of concentrated nitric acid at 60 ° C. for 1 hour to give 1-bromo-3-nitro compound represented by the formula (13).
4- (p-Toluenesulfonyl) aminonaphthalene is obtained.

[0040]

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Next, 1-bromo-3- represented by the formula (13)
Concentrated sulfuric acid was added to nitro-4- (p-toluenesulfonyl) aminonaphthalene at 70 ° C for 10 minutes, a mixture of sodium nitrite and concentrated sulfuric acid was cooled on ice for 30 minutes, and a mixture of acetic acid and sodium hydrogencarbonate was added at room temperature for 12 minutes. By acting continuously over time, 5-bromonaphtho [3,4-d] oxadiazole represented by the formula (14) is obtained.

[0042]

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Next, 5-bromonaphtho [3,4-d] oxadiazole represented by the formula (14) and an aqueous solution of hypophosphorous acid are mixed in a mixed solvent of methanol and tetrahydrofuran (hereinafter abbreviated as THF). By heating under reflux for a period of time, the formula (15)
To obtain 4-bromo-2-naphthol.

[0044]

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Next, 4-bromo- represented by the formula (15)
By reacting 2-naphthol with 2.0 equivalents of diisopropylethylamine and 1.2 equivalents of methoxymethyl chloride in dichloromethane at room temperature for 2 hours, the hydroxyl group of 4-bromo-2-naphthol was protected with a methoxymethyl group. 1-bromo-3- (methoxymethyloxy) naphthalene is obtained.

[0046]

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(Where MOM represents a methoxymethyl group)

Next, 1-bromo-3- represented by the formula (16)
(Methoxymethyloxy) naphthalene and 3.0 equivalents of a diarylamine represented by the general formula (17) or a diphenylamine derivative represented by the general formula (18), 3.0 equivalents of sodium-t-butoxide, 0.03 equivalents of tris (dibenzylidene) Acetone) dipalladium (0) and 0.045
An equivalent amount of 1,1′-bis (diphenylphosphino) ferrocene is refluxed and heated in toluene for 24 hours to obtain a compound represented by the general formula (19) or (20).

[0049]

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(Where Ar ₁ and Ar ₂ are each independently selected from aryl groups)

[0051]

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(Wherein, R _{1 to} R ₁₀ are each independently selected from a hydrogen atom, a lower alkyl group, or a lower alkoxy group)

[0053]

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(Where Ar ₁ and Ar ₂ are each independently selected from aryl groups)

[0055]

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(Wherein, R _{1 to} R ₁₀ are each independently selected from a hydrogen atom, a lower alkyl group, or a lower alkoxy group)

Next, the general formula (19) or the general formula (2)
By heating the compound represented by the formula (1) and 1.0 equivalent of p-toluenesulfonic acid monohydrate in a mixed solvent of methanol and THF at 50 ° C. for 2 hours, the compound represented by the general formula (21) or the general formula The compound represented by (22) is obtained.

[0058]

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(Where Ar ₁ and Ar ₂ are each selected from an independent aryl group)

[0060]

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(Wherein, R _{1 to} R ₁₀ are each independently selected from a hydrogen atom, a lower alkyl group, or a lower alkoxy group)

Diaminonaphthol obtained by reacting a compound represented by formula (21) or (22) with 1.5 equivalents of an aqueous solution of a diazonium salt of sulfanilic acid and 10 equivalents of sodium hydrosulfanyl. An intermediate represented by the general formula (3) or (4) is obtained by introducing an amino-protecting group into the primary amino group of the derivative. Introduction of a protecting group for an amino group can be performed by a known method, for example, TWGreen. Et al., "Protecting Groups in Organi.
c Synthesis "2nd Ed., John-Wiley & Sons, New York, 199
1, p317-397.

Hereinafter, typical examples of the phenoxazone compound of the present invention and intermediates thereof are specifically shown in Tables 1 and 2, but the present invention is not limited to the following typical examples.

[0064]

[Table 1]

[0065]

[Table 2]

The phenoxazone compound obtained by the above procedure is purified by a recrystallization method or a vacuum sublimation method.
It can be used as a dopant.

The structure of an organic thin film EL device using the phenoxazone derivative of the present invention as a red light-emitting material includes, specifically, (a) an anode / hole transport layer / cathode, and (b) an anode / hole transport layer / Electron transport layer / cathode, (c) anode / hole injection layer /
Hole transport layer / electron transport layer / cathode, (d) anode / hole injection layer / hole transport layer / electron transport layer / electron injection layer / cathode,
(E) In an element having a structure such as an anode / hole transport layer / electron transport layer / electron injection layer / cathode, and (f) an anode / electron transport layer / cathode, the general formula (1) or (2) The phenoxazone derivative represented is characterized in that at least one phenoxazone derivative is doped in the hole transport layer or the electron transport layer. The element is desirably supported on a transparent insulating substrate made of glass, transparent plastic, quartz, or the like.

Next, an embodiment of the organic thin-film EL device of the present invention will be described based on the above configuration (d) with reference to FIG. First, as a material used for the anode (2) formed on the transparent insulating substrate (1), a transparent oxide material such as ITO, SnO ₂ , ZnO and the like can be mentioned. The anode (2) is formed by forming a thin film from these electrode materials by a method such as evaporation or sputtering.

Next, the compound used for the hole injection layer (3) is a compound which is disposed between a pair of electrodes to which an electric field is applied, and which can inject holes from the anode, and has a good adhesion to the anode. Higher compounds are chosen. Specifically, copper phthalocyanine, 4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triphenylamine, or a compound represented by the formula (2)
And the compounds represented by 3). The hole injection layer (3) is formed by depositing these compounds on the anode (2).

[0070]

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The compound used for the hole transport layer (4) is selected from materials capable of appropriately transporting holes. The material may be selected from materials commonly used as hole transport materials in electrophotographic materials, and materials known as hole transport materials in organic thin film EL materials. Specifically, N, N'-
Diphenyl-N, N'-bis (1-naphthyl) -1,
1′-biphenyl-4,4′-diamine (hereinafter abbreviated as α-NPD), N, N′-diphenyl-N, N′-bis (3-
Methylphenyl) -1,1′-biphenyl-4,4′-
And diamines. The hole transport layer (4) is formed by depositing these compounds on the hole injection layer (3).

The electron transporting light emitting layer (5) is an organic thin film EL device obtained by doping a light emitting material of the present invention at a concentration of 0.01 to 10% by weight into an electron transporting material capable of appropriately transporting electrons. Refers to a layer responsible for light emission of the element when a voltage is applied between the pair of electrodes. Here, Alq ₃ is used as the electron transporting material. Examples of the light emitting material used as the dopant include at least one of the phenoxazone derivatives represented by the formula (1) or (2). The electron transporting light emitting layer (5) is formed by co-evaporating an electron transporting material and a light emitting material on the hole transporting layer (4). Further, an electron injecting layer (6) made of an organic material having an electron transporting property is formed on the electron transporting and emitting layer of (5) by a vapor deposition method.

As the cathode (7), a metal, an alloy, or an electrically conductive compound having a small work function (4.0 eV or less) is used as an electrode material. Specific examples include aluminum,
It is selected from a magnesium-indium alloy, a silver-magnesium alloy, an aluminum-lithium alloy, a fluorine-lithium alloy and a combination thereof. Further, a layer having a function of blocking atmospheric moisture and oxygen, such as a sealing layer and a protective layer, may be provided above the cathode (7).

[0074]

The present invention will be described below in more detail with reference to examples.

Example 1 Synthesis of Intermediate (A-1) 1-Naphthylamine represented by the formula (10) (25.4 g, 178 mmol)
l) and p-toluenesulfonic acid chloride (33.8 g, 178 mmo
A solution of l) in pyridine (100 ml) was stirred at 80 ° C. for 2 hours. The residue obtained by evaporating the reaction mixture under reduced pressure was dissolved in acetone (500 ml), poured into water (1000 ml) and stirred for 30 minutes. The deposited precipitate was filtered and further stirred in a mixed solvent of water / ether / hexane (2: 1: 1) (1000 ml) for 30 minutes. The precipitate was filtered, sufficiently washed with water, and dried under reduced pressure to obtain 1- (p-toluenesulfonyl) aminonaphthalene (51.7 g, 174 mmol, 98%) represented by the formula (11) as a white powder. Can be

Next, 1- (p-toluenesulfonyl) aminonaphthalene (51.7 g, 174 mmol) represented by the formula (11)
A 29.0 g / 50 ml bromine-acetic acid solution (3.6 ml) was added to the DMF solution (100 ml).
M, 47.9 ml, 174 mmol) was slowly added in an ice bath,
Stirred for hours. The reaction mixture was poured into water (1000ml) and stirred for 30 minutes. The precipitated precipitate is filtered, sufficiently washed with water, and dried under reduced pressure, whereby 1- represented by the formula (12) is obtained.
Bromo-4- (p-toluenesulfonyl) aminonaphthalene
(62.9 g, 167 mmol, 96%) is obtained as a white powder.

The 1-bromo-4- (p-) represented by the formula (12)
Toluenesulfonyl) aminonaphthalene (62.9 g, 167 mmo
A concentrated hydrochloric acid (12.6 ml, 200 mmol) in acetic acid (100 ml) was added to an acetic acid solution (400 ml) in 1), and the mixture was stirred at 60 ° C. for 1 hour. The reaction mixture was cooled to room temperature, and the deposited precipitate was filtered,
Washed thoroughly with water. The precipitate was recrystallized from methanol to give 1-bromo-3-nitro-4- (p-toluenesulfonyl) aminonaphthalene (57.
7g, 137mmol, 82%) are obtained as yellow crystals.

1-bromo-3-nitro represented by the formula (13)
-4- (p-toluenesulfonyl) aminonaphthalene (9.59
g, 22.8 mmol) in a water / concentrated sulfuric acid (1/9) mixed solution (20 ml).
Stirred at C for 10 minutes. A concentrated sulfuric acid solution (7 ml) of sodium sulfite (1.73 g, 25.0 mmol) was slowly added to the mixture under ice-cooling, and the mixture was stirred for 30 minutes.Acetic acid (10 ml) was added in an ice bath, and the mixture was further stirred at room temperature for 30 minutes. did. 3000 ml of reaction mixture
Into the ice water and slightly acidify sodium bicarbonate (about 70 g)
(pH 6), and the mixture was stirred at room temperature for 12 hours. The precipitated precipitate is filtered, sufficiently washed with water, and then dried under reduced pressure to give 5-bromonaphtho represented by the formula (14).
[3,4-d] oxadiazole (4.90 g, 19.7 mmol, 86%) is obtained as an orange powder.

The 5-bromonaphtho [3,4 represented by the formula (14)
-d] Oxadiazole (4.90 g, 19.7 mmol) in methanol / T
50% hypophosphorous acid aqueous solution in HF (1/1 v / v) mixed solution (20 ml)
(5 ml) was added and the mixture was heated under reflux for 5 hours. The solvent was distilled off from the reaction mixture under reduced pressure to obtain a residue. The residue obtained is ethyl acetate
(200 ml), and washed successively with a saturated aqueous solution of sodium bicarbonate and a saturated saline solution. The organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure to obtain a residue. The obtained residue was purified by silica gel chromatography (ethyl acetate: hexane = 1: 4) to give 4-bromo-2-naphthol (3.02 g, 13.2 g) represented by the formula (15).
(5 mmol, 69%) is obtained as a white powder.

To a dichloromethane solution (15 ml) of 4-bromo-2-naphthol (3.02 g, 13.5 mmol) represented by the formula (15) and diisopropylethylamine (4.71 ml, 27.1 mmol) were added.
Methoxymethyl chloride at room temperature under argon atmosphere
(1.23 ml, 16.3 mmol) was added and stirred for 1 hour. Water (30ml)
Was added to the reaction mixture and extracted with dichloromethane (30 ml) three times. The extract was washed with saturated saline, and the organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure to obtain a residue. The obtained residue is purified by silica gel chromatography (ethyl acetate: hexane = 0: 1 → 1: 10) to give 1-bromo-3- (methoxymethyloxy) naphthalene represented by the formula (16). (3.17g, 12.1mmol, 90%)
Is obtained as a colorless liquid.

1-bromo-3- (methoxymethyloxy) naphthalene represented by the formula (16) (1.43 g, 5.36 mmol), tris
(Dibenzylideneacetone) dipalladium (0) (147mg, 0.
161 mmol), 1,1'-bis (diphenylphosphino) ferrocene (134 mg, 0.241 mmol) and sodium-t-butoxide (1.55 g, 16.1 mmol) in toluene (5.0 ml) were frozen and degassed, followed by replacement with argon. did. This solution was frozen and degassed,
A toluene solution (5.0 ml) of diphenylamine (2.72 g, 16.1 mmol) in which R _{1 to} R ₁₀ are hydrogen atoms among the compounds represented by the formula (18) was added, and the mixture was heated under reflux for 24 hours. The reaction mixture was cooled to room temperature, ethyl acetate (50 ml) was added, and the mixture was filtered through celite. The filtrate was washed with saturated saline, and the organic layer was dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to obtain a residue. The obtained residue is purified by silica gel chromatography (ethyl acetate: hexane = 0: 1 → 1: 10) to obtain a compound represented by the formula (20) wherein R1 to R10 are hydrogen atoms. 1-diphenylamino-3-
(Methoxymethyloxy) naphthalene (1.20 g, 3.37 mmol,
63%) as a colorless liquid.

Among the compounds represented by the formula (20), R _{1 to} R
1-diphenylamino-3- (methoxymethyloxy) naphthalene (1.08 g, 3.03 mmol) and p- in which ₁₀ is a hydrogen atom
A methanol solution (10.0 ml) of toluenesulfonic acid monohydrate (1.15 g, 6.05 mmol) was stirred at 50 ° C. for 2 hours. The solvent obtained by evaporating the reaction mixture under reduced pressure was diluted with dichloromethane.
(200 ml), and the mixture was washed successively with a saturated aqueous solution of sodium hydrogen carbonate and a saturated saline solution. The organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure to obtain a residue. The resulting residue was purified by silica gel chromatography (ethyl acetate: hexane = 1: 6) to give the compound of the formula (22)
Wherein R _{1 to} R ₁₀ are hydrogen atoms among the compounds represented by
Diphenylamino-2-naphthol (0.906 g, 2.91 mmol, 96
%) As a colorless liquid.

Next, a diazonium salt of sulfanilic acid is prepared as follows. Sulfanilic acid (1.06 g, 6.1
7 mmol) and sodium carbonate (0.436 g, 4.11 mmol) in water (8
was dissolved by heating, cooled to room temperature, and an aqueous solution (4 ml) of sodium nitrite (0.482 g, 6.99 mmol) was added.
This mixture was slowly added to 2.4M hydrochloric acid (9.6 ml) under ice cooling, and the mixture was stirred under ice cooling for 1 hour.

Next, among the compounds represented by the formula (22),
An aqueous solution of sodium hydroxide (3.2 g, 80 mmol) (0.2 ml) was added to a methanol solution (150 ml) of 4-diphenylamino-2-naphthol (1.28 g, 4.11 mmol) in which R _{1 to} R ₁₀ are hydrogen atoms, The diazonium salt aqueous solution of sulfanilic acid prepared above was slowly added under ice cooling, and the mixture was stirred under ice cooling for 1 hour. Hydrosulfanyl sodium is added to the reaction mixture.
(7.16 g, 41.1 mmol) aqueous solution (80 ml)
-t-butyl (4.49 g, 20.6 mmol) was added.
Stirred for hours. Then, the solvent in the reaction mixture was distilled off under reduced pressure, and the obtained aqueous solution was diluted with ethyl acetate (300 ml).
The organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure to give 1- (t-butoxycarbonylamino) -4-diphenyl, an intermediate (A-1) shown in Table 1. Amino-2-naphthol is obtained as a brownish viscous body.

The results of ¹ H-NMR spectrum of the chloroform solution of (A-1) were as follows. ¹ H-NMR (250 MHz, CDCl ₃ ) δ [ppm]: 1.85 (9H, s, Boc), 6.69
(14H, brs), 6.90 (1H, brs), 7.55 (1H, brs), 7.95 (1H, brs)

The mass spectrum measured for (A-1) was as follows. CIMS (m / z): 427 (M + 1) +, 426 (M +), 411 (M -CH 3) +

Example 2 Synthesis of Phenoxazone Compound (B-1) Unpurified 1- (t-butoxycarbonylamino) -4-diphenylamino-2-naphthol represented by (A-1) and a compound represented by the formula ( 2-hydroxy-1,4-naphthoquinone represented by 9) (1.43 g,
8.24 mmol) and p-toluenesulfonic acid monohydrate in DMF
The solution (10 ml) was stirred at 80 ° C. for 24 hours. After the reaction mixture was cooled to room temperature, it was poured into water (100 ml) and stirred for 30 minutes. The precipitated precipitate is filtered, and the precipitate is diluted with dichloromethane (100 ml).
And washed with saturated saline. The organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure to obtain a residue. The obtained residue was purified by silica gel chromatography (dichloromethane) and further recrystallized from ethyl acetate to give the compound (B-
1) 9-Diphenylamino-5H-dibenzo [a, j] phenoxazin-5-one (230 mg, 12%) was obtained as red-brown crystals.

The result of the IR spectrum measured for (B-1) was as follows. IR (KBr, νcm ^-1 ): 3065 (w), 2935 (w), 2924 (m), 2852 (w), 16
30 (s), 1618 (s), 1589 (s), 1570 (s), 1562 (s), 1489 (s), 1460
(w), 1448 (w), 1431 (w), 1408 (w), 1342 (m), 1309 (m), 1292
(w), 1261 (s), 1230 (w), 1215 (m), 1159 (w), 1067 (m), 1080
(w), 1028 (w), 1005 (m), 908 (m), 844 (w), 777 (m), 757 (m), 73
1 (s), 696 (m), 673 (w), 646 (w), 619 (w), 601 (w), 532 (w), 511
(w), 468 (w), 420 (w).

The result of the ¹ H-NMR spectrum measured for (B-1) was as follows. ¹ H-NMR (500 MHz, CDCl ₃ ) δ (p
pm]: 6.46 (1H, s ), 7.05-7.10 (6H, m (d + t), NPh 2), 7.18 (1H,
s), 7.28 (4H, t , J = 8.6, NPh 2), 7.41 (1H, dt, J = 0.9,7.6), 7.7
1 (1H, dt, J = 0.9,7.6), 7.78 (1H, dt, J = 0.9,7.6), 7.84 (1H, d
t, J = 0.9,7.6), 7.91 (1H, d, J = 8.3), 8.37 (1H, dd, J = 0.9,7.
9), 8.97 (1H, dd, J = 0.9, 7.9), 9.09 (1H, d, J = 8.3).

The mass spectrum measured for (B-1) was as follows. EIMS (m / Z): 464 (M ⁺ ). HRMS Calcd for C32H20N2O2 (M ⁺ ): 464.1524. Found 464.1504.

[Example 3] Organic thin-film EL element using phenoxazone compound represented by (B-1) described in Example 2 as a dopant FIG. 2 is a cross-sectional view of an organic thin-film EL element according to Example 3. is there.

In FIG. 2, (11) is an anode made of ITO (ITO is transparent and also serves as a light extraction window), (12) is a hole injection layer 1 made of copper phthalocyanine, and (13) is a hole injection layer. The hole injection layer 2 composed of the formula (23), (14) is a hole transport layer composed of α-NPD represented by the formula (24), and (15) is an electron transport composed of Alq ₃ represented by the formula (25). An electron transporting / emitting layer formed by doping the material with a phenoxazone compound represented by (B-1); (16) an electron injecting layer composed of a single component of Alq ₃ ; (17) LiF and Al in order This is a stacked cathode.

[0093]

Embedded image

[0094]

Embedded image

The production of the organic thin film EL device was performed as follows. First, on a 1.1 mm-thick blue glass plate used as a transparent insulating substrate (10), a 120-nm thick
Was coated by sputtering to form an anode (11). On this anode (11), a hole injection layer 1 (12)
10 nm thick copper phthalocyanine as the hole injection layer 2
A compound represented by the formula (23) as (13) having a film thickness of 30
nm, α-NPD represented by the formula (24) as a hole transport layer (14) was vacuum-deposited in order so as to have a film thickness of 10 nm.

Next, Alq _{3 represented} by the formula (25) and (B-
The phenoxazone compound represented by 1) was deposited at a deposition rate ratio of 10
0: 1 co-evaporation, and a 40 nm-thick electron transporting light emitting layer (1
5).

Next, Alq _{3 represented} by the formula (25) was deposited to form an electron injection layer (16) having a thickness of 10 nm.

Next, after about 0.5 nm of LiF was deposited, about 200 nm of Al was finally deposited to form a cathode (17).

A lead (18) and a DC power supply (1)
9) was connected and a voltage was applied in the forward direction. As shown in FIG. 3, light emission started from a voltage of 6 V, and when the voltage reached 13 V, light was emitted stably at a luminance of 1800 cd / m ² . This device emits red light having a peak at 655 nm as shown in FIG. The luminous efficiency of this device was 0.035 lm / W at an applied voltage of 6 V.

If the concentration of the phenoxazone compound according to the present invention with respect to the host material in the hole transporting layer or the electron transporting layer is 0.01% by weight or less, light emission at a sufficient concentration cannot be obtained. When the content is 10% by weight or more, it is difficult to obtain efficient light emission due to restriction of charge transfer or interaction between dopants.

[0101]

As described above, the novel phenoxazone compound according to the present invention, when used as a dopant, can stably emit red light with high luminance by using an organic thin film E.
An L element can be obtained.

[Brief description of the drawings]

[0102]

FIG. 1 is a cross-sectional view of one configuration of an organic thin film EL device according to the present invention.

FIG. 2 is a sectional view of an organic thin-film EL device according to a third embodiment of the present invention.

FIG. 3 is a graph showing the relationship between driving voltage and light emission luminance in the organic thin film EL device manufactured in Example 3 of the present invention.

FIG. 4 is an emission spectrum of an organic thin-film EL device according to Example 3 of the present invention.

[Explanation of symbols]

 (1) ... transparent insulating substrate (2) ... anode (3) ... hole injection layer (4) ... hole transport layer (5) ... electron transport light emitting layer (6) ··· Electron injection layer (7) ··· Cathode (8) ··· Conductor (9) ··· DC power supply (10) ··· Transparent insulating substrate (11) ··· Anode (12)・ Hole injection layer 1 (13) ・ ・ ・ Hole injection layer 2 (14) ・ ・ ・ Hole transport layer (15) ・ ・ ・ Electron transport light emitting layer (16) ・ ・ ・ Electron injection layer (17) ・..Cathode (18) Conductor (19) DC power supply

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Shoji Higuchi, Inventor, Printing and Printing Co., Ltd., 1-1-5 Taito, Taito-ku, Tokyo (72) Inventor Tadashi Kato 4-8-13- Chiyoda, Sagamihara-shi, Kanagawa 305 (72) Fusae Miyata 2-53-5 Denon Chofu, Ota-ku, Tokyo (72) Osamu Omori 4-4-1 Nishi-Onuma, Sagamihara-shi, Kanagawa F-term (reference) 3K007 AB02 AB04 CA01 CB01 CB03 DA00 DB03 EB00 FA01 4C056 AA02 AB01 AC03 AD02 AE03 EA01 EB01 EC01 ED06 ED08 4H006 AA01 AB92 BJ50 BN30 BU48

Claims (6)

[Claims] 1. A phenoxazone compound represented by the general formula (1). Embedded image (Where Ar ₁ and Ar ₂ are each independently selected from aryl groups) 2. The phenoxazone compound according to claim 1, which is represented by the general formula (2). Embedded image (Where R _{1 to} R ₁₀ are each independently selected from a hydrogen atom, a lower alkyl group, or a lower alkoxy group) 3. A diaminonaphthol derivative represented by the general formula (3). Embedded image (Here, Ar ₁ and Ar ₂ are each independently selected from an aryl group. R ₁₁ represents a protecting group for an amino group.) 4. The diaminonaphthol derivative according to claim 3, which is represented by the general formula (4). Embedded image (Here, R _{1 to} R ₁₀ are each independently selected from a hydrogen atom, a lower alkyl group, and a lower alkoxy group. R ₁₁ represents a protecting group for an amino group.) 5. An organic thin-film EL device having at least one hole transport layer made of an organic compound and at least one electron transport layer between a pair of electrodes, wherein the phenoxazone compound according to claim 1 or 2 is provided in the hole transport layer. Or an organic thin film E characterized in that at least one type is doped in the electron transport layer.
L element. 6. The organic thin film EL device according to claim 5, wherein the concentration of the phenoxazone compound according to claim 1 or 2 relative to the host material in the hole transport layer or the electron transport layer is 0.01 to 10% by weight. Characteristic organic thin-film EL element.