JP2000095766A - Novel benzommidazole compound, its production and use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a novel compound excellent in durability and useful as a charge-transporting material of electrophotographic photoreceptors, organic electroluminescent elements, etc. SOLUTION: This novel benzoimidazole compound is expressed by formula I [A is an arylene which may be bonded with a bonding group; Ar1 and Ar2 are each a (substituted)aryl or a heterocycle; R1 and R2 are each H, an alkyl, an alkoxy or the like], e.g. a compound expressed by formula II. The compound of formula I is obtained by reacting, e.g. a compound of formula II (e.g. a compound of formula IV or the like) with a compound of the formula Ar1-X, Ar2-X (X is a halogen), (e.g. a compound of formula V, etc.), in the presence of a catalyst such as a dehydrohalogenation agent, etc., (e.g. anhydrous potassium carbonate, etc.), or the like and a solvent such as o-dichlorobenzene or the like at preferably 50-200 deg.C, generally under the normal pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel benzimidazole compound, a method for producing the same, and a use thereof. The benzimidazole compound of the present invention can be used for photosensitive materials, organic photoconductive materials and the like. More specifically, the benzimidazole compound of the present invention is useful for an organic electroluminescence element or an electrophotographic photosensitive member used for a surface light source or display.

[0002]

2. Description of the Related Art Organic photoconductive materials which have been developed as photoreceptors and charge transport materials have many advantages such as low cost, various processability, and no pollution, and many compounds have been proposed. ing.

For example, oxadiazole compounds, hydrazone compounds, pyrazoline compounds, oxazole compounds,
Organic photoconductive materials such as arylamine compounds, benzidine compounds, stilbene compounds, and butadiene compounds have been proposed.

One of the techniques using a charge transport material is an electrophotographic photosensitive member. The electrophotographic method is one of the image forming methods invented by Carlson. In this method, a photoreceptor is charged by corona discharge, image exposure is performed to form an electrostatic latent image on the photoreceptor, toner is adhered onto the electrostatic latent image, and the electrostatic latent image is developed. Is transferred to paper.

[0005] The basic characteristics required of the photoreceptor in such an electrophotographic system are that an appropriate potential is maintained in a dark place, that the electric charge is less dissipated in the dark place, and that the light is promptly irradiated with light. Dissipating the charge may be mentioned.

Until now, an electrophotographic photosensitive member has used an inorganic photoconductor such as selenium, a selenium alloy, zinc oxide, and cadmium sulfide. These inorganic photoconductors have advantages such as high durability and a large number of printing presses, but problems such as high production cost, poor workability, and toxicity have been pointed out. .

To overcome these drawbacks, organic photoconductors have been developed. However, conventional electrophotographic photoconductors using an organic photoconductor as a charge transporting material have a problem in chargeability, sensitivity and residual charge. At present, electrophotographic properties such as potential are not always satisfactory, and development of a charge transport material having excellent charge transport ability and durability has been desired.

[0008] Other techniques utilizing charge transport materials include:
Organic electroluminescent elements are exemplified. Electroluminescent devices using organic compounds are expected to be used as inexpensive large-area, full-color display devices of the solid-state emission type, and much research has been conducted.

In general, an organic electroluminescent element is composed of a light emitting layer and a pair of counter electrodes sandwiching the light emitting layer. In light emission, when an electric field is applied between both electrodes, electrons are injected from a cathode and holes are injected from an anode. Further, the electrons and holes are recombined in the light emitting layer, and the energy is emitted as light when the energy level returns from the conduction band to the valence band.

A conventional organic electroluminescent device has a higher driving voltage and lower luminous brightness and luminous efficiency than inorganic electroluminescent devices. In addition, the characteristics deteriorated remarkably and did not reach practical use.

In recent years, an organic electroluminescence device in which a thin film containing an organic compound having a high fluorescence quantum efficiency and emits light at a low voltage of 10 V or less has been reported and has been attracting attention (Applied Physics Letters,
51, 913, 1987). This method uses a metal chelate complex for a phosphor layer and an amine compound for a hole injection layer to obtain high-luminance green light emission.
With a DC voltage of, a luminance of several hundred cd / m ² and a maximum luminous efficiency of 1.5 lm / W are achieved, and the performance is close to the practical range.

[0012] However, the organic EL device to date has been improved in light emission intensity due to the improved structure, but does not yet have sufficient light emission luminance. In addition, there is a major problem that the stability upon repeated use is poor. Therefore, in order to develop an organic electroluminescent device having higher emission luminance and excellent stability during repeated use, it is desired to develop a charge transport material having excellent charge transport ability and durability. It is rare.

[0013]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel benzimidazole compound useful as a durable charge transport material and its production. It is to provide a method and its use.

[0014]

That is, the present invention provides a novel benzimidazole compound represented by the following general formula (I):

Embedded image (Wherein, A represents an arylene group or a heterocyclic group which may be bonded by a linking group; Ar ₁ and Ar ₂ each represent an aryl group or a heterocyclic group which may have a substituent; R ₁ and R ₂ is each independently a hydrogen atom, an alkyl group,
Represents an alkoxy group or a halogen atom).

In the general formula (I), A can be an arylene group such as a phenylene group, a biphenylene group or a naphthylene group, and is preferably a phenylene group or a biphenylene group. The arylene group may have a substituent such as an alkyl group. A may be an arylene group bonded by a linking group. The linking groups are -O-, -S-, -R
-(R represents an alkylene group which may have a substituent such as an alkyl group or an arylene group). A is a heterocyclic 2 such as thiophene or pyrrole.
It may be a valence group. It is preferably a divalent group of a thiophene ring.

Ar ₁ and Ar ₂ each independently represent an aryl group such as a phenyl group, a diphenyl group or a naphthyl group, preferably a phenyl group or a diphenyl group, or a heterocyclic group such as a thienyl group, a furyl group or a pyrrolyl group; Can be a thienyl group. The aryl group or the heterocyclic group may have a substituent such as a C1 to C5 alkyl group or a diarylamino group. The aryl group may have a substituent such as an alkyl group and a methoxy group.

R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. Preferably it is a hydrogen atom or a lower alkyl group.

The benzimidazole compound represented by the general formula (I) can be produced by using a known reaction, for example, a benzimidazole compound represented by the following general formula (II);

Embedded image (Wherein, A, R ₁ and R ₂ have the same meanings as in formula (I))
And a halogen compound represented by the following general formula (III);

Embedded image (Wherein, Ar ₁ and Ar ₂ have the same meanings as in formula (I); X represents a halogen atom).

The above reaction can be carried out by a condensation reaction in the presence of a catalyst such as a dehydrohalogenating agent and a solvent.

As the catalyst used in the synthesis, alkali metal hydroxides, carbonates, bicarbonates, alcoholates and the like are generally used, and quaternary ammonium compounds, aliphatic amines and aromatic amines are used. It is also possible to use a suitable organic base. Of these, alkali metal and quaternary ammonium carbonates and bicarbonates are preferably used. Furthermore, alkali metal carbonates and bicarbonates are most preferred from the viewpoints of reaction rate and thermal stability.

A transition metal or a transition metal compound may be used as a catalyst. Examples of the transition metal or transition metal compound include Cu, Fe, Co, Ni, Cr, V, Pd, Pt,
Although metals such as Ag and their compounds are used, copper and palladium and their compounds are preferred in terms of yield. The copper compound is not particularly limited, and most copper compounds are used, but cuprous iodide, cuprous chloride, cuprous oxide, cuprous bromide, cuprous cyanide, cuprous sulfate ,
Cupric sulfate, cupric chloride, cupric hydroxide, cupric oxide,
Cupric bromide, cupric phosphate, cuprous nitrate, cupric nitrate,
Copper carbonate, cuprous acetate, cupric acetate and the like are preferred. Among them, in particular, CuCl, CuCl, CuBr, CuBr ₂ , CuI,
CuO, Cu ₂ O, CuSO ₄ , and Cu (OCOCH ₃ ) ₂ are preferred in that they are easily available. As the palladium compound, halides, sulfates, nitrates, organic acid salts and the like can be used. The used amount of the transition metal and its compound is 0.5 to 500 mol% of the halogen compound to be reacted.

The solvent used in the synthesis may be any commonly used solvent, but aromatic solvents such as benzene, toluene, chlorobenzene and xylene are preferably used. The synthesis reaction is generally performed at a temperature of 50 to 200 ° C. under normal pressure, but may be performed under pressure.
After completion of the reaction, after removing solid substances precipitated in the reaction solution,
The product can be obtained by removing the solvent.

The following are specific examples of the benzimidazole compound of the present invention. These examples are not intended to limit the benzimidazole compound of the present invention or to disclose the benzimidazole compound of the present invention.

[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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The benzimidazole compound represented by the general formula (I) of the present invention has an excellent charge transporting function, especially a hole transporting function, and has excellent durability and heat resistance. Therefore, the benzimidazole compound represented by the general formula (I) of the present invention is excellent in use as a charge transporting material, and various applications can be considered by utilizing such a function. For example, a photoconductor or an organic electroluminescent compound can be used. It can be suitably used as a charge transport material of a sense element.

First, the case where the benzimidazole compound represented by the general formula (I) of the present invention is used for an electrophotographic photosensitive member will be described.

The benzimidazole compound represented by the general formula (I) of the present invention can be used in any layer of an electrophotographic photoreceptor, but is preferably used as a charge transport material because of its high charge transport properties. . Since the compound of the present invention acts as a charge transporting substance and can transport charges generated by light absorption or injected from an electrode very efficiently, it is possible to obtain a photoreceptor excellent in sensitivity and high-speed response. Further, the compound has ozone resistance,
Since it has excellent light stability, it is possible to obtain a photosensitive member having excellent durability.

Examples of the electrophotographic photoreceptor include, for example, a photoreceptor having a photosensitive layer formed by dispersing a charge generating material and a charge transporting material in a resin solution on a support; A photoreceptor comprising a generating layer and a charge transport layer laminated thereon, a photoreceptor comprising an undercoat layer or a conductive layer and an undercoat layer formed on a support, and a photosensitive layer formed thereon, or a support There is a photoreceptor obtained by sequentially laminating an undercoat layer, a photosensitive layer and a surface protective layer thereon.

As the support, copper, aluminum, iron,
A foil made of nickel, stainless steel, or the like, or a plate or drum-shaped one is used. These metals are vacuum-deposited or electroless-plated on paper or plastic drums, or a layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide is applied or deposited on paper or plastic drums. Can also be used. Generally aluminum is used, for example,
After extrusion, the drawn aluminum pipe is cut, and the outer surface is cut to about 0.2 to 0.3 mm using a cutting tool such as a diamond bite, and finished (cutting tube) or aluminum After the disk was deep drawn and cup-shaped, the outer surface was finished by ironing (DI pipe). After the aluminum disk was impact-processed into a cup shape, the outer surface was finished by ironing. (EI tube), extruded and then cold drawn
(ED tube) and the like. Further, those obtained by further cutting these surfaces may be used.

When an undercoat layer is formed on a support, an oxide film obtained by anodizing the surface of the support is often used as the undercoat layer. When the support is an aluminum alloy, it is effective to use an alumite layer as an undercoat layer. Alternatively, it is formed by dispersing a low-resistance compound in a solution in which a suitable resin is dissolved or in the solution, applying the solution or dispersion on the conductive support, and drying. In this case, as a material used for the undercoat layer, polyimide, polyamide, nitrocellulose, polyvinyl butyral, polyvinyl alcohol, or the like is appropriate, and a low-resistance compound may be dispersed in these resins. As the low-resistance compound, metal compounds such as tin oxide, titanium oxide, zinc oxide, zirconium oxide, and magnesium fluoride, and organic compounds such as organic pigments, electron-withdrawing organic compounds, and organic metal complexes are preferably used. The thickness of the undercoat layer is 0.1 to 5 μm
m, preferably 0.2 to 3 μm.

A photosensitive layer is formed on the support or the undercoat layer. Hereinafter, a case where a charge generation layer and a charge transport layer are laminated as the photosensitive layer will be described.

In forming the charge generation layer on the conductive substrate, the charge generation material is vacuum-deposited, dissolved in an appropriate solvent and applied, or a pigment is coated with an appropriate solvent or if necessary. A coating solution prepared by dispersing in a solution in which a resin is dissolved is formed by coating and drying. From the standpoint of adhesiveness, those dispersed in a resin are good. The thickness of the charge generation layer is preferably from 0.01 to 2 μm, and more preferably from 0.05 to 1 μm.

Examples of the charge generating material used in the charge generating layer include azo pigments (including bisazo pigments and trisazo pigments), triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, and cyanine dyes. Dyes, styryl dyes, pyrylium dyes, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indathrone pigments, squarylium pigments, phthalocyanine pigments Organic pigments such as pigments and dyes are exemplified. In addition to these, any material can be used as long as it absorbs light and generates charge carriers with a very high probability, but any of azo (bis, tris) pigments and phthalocyanine-based pigments can be used. Pigments are preferred.

Examples of the resin used together with the charge generating material include a saturated polyester resin, a polyamide resin, an acrylic resin, an ethylene-vinyl acetate copolymer, an ion-crosslinked olefin copolymer (ionomer), and a styrene-butadiene block. Copolymer, polyarylate, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, styrene resin, polyacetal resin, thermoplastic binder such as phenoxy resin, epoxy resin, urethane resin, silicone resin, phenol resin Use of thermosetting binders such as melamine resin, xylene resin, alkyd resin, thermosetting acrylic resin, photocurable resin, photoconductive resin such as poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene Can

The above-mentioned charge generating material is used together with these resins together with alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and amides such as N, N-dimethylformamide and N, N-dimethylacetamide. , Sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, and aliphatic halogens such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride, and trichloroethylene. A photosensitive coating solution prepared by dispersing or dissolving in an organic solvent such as an aromatic hydrocarbon such as a fluorinated hydrocarbon or benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. Coated on conductive substrate,
It is made to dry and to provide a charge generation layer.

The photoreceptor of the present invention can be obtained by providing a charge transport layer containing a charge transport material and a binder resin on the charge generation layer formed as described above.

As the binder resin, for example, polycarbonate, polyarylate, saturated polyester resin,
Polyamide resin, acrylic resin, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer), styrene-butadiene block copolymer, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, styrene resin, polyacetal Resin, thermoplastic binder such as phenoxy resin, epoxy resin, urethane resin, silicone resin, phenol resin, melamine resin, thermosetting binder such as xylene resin, alkyd resin, thermosetting acrylic resin, photo-curable resin And a photoconductive resin such as poly-N-vinylcarbazole, polyvinylpyrene and polyvinylanthracene.

In forming the charge transport layer of the photoreceptor of the present invention, a coating solution obtained by dissolving a charge transport material and a binder resin in an appropriate solvent is applied on the above-mentioned charge generation layer, dry. The thickness of the charge transport layer is 5 to 5.
60 μm, preferably about 10 to 50 μm is desirable. Further, the content of the charge transporting material in the charge transporting layer cannot be specified unconditionally depending on the type thereof, but is generally 0.02 to 2 parts by weight, preferably 0.5
It is desirable to add 〜1.2 parts by weight.

As the charge transporting material used in the present photoreceptor, two or more kinds of the benzimidazole compounds represented by the general formula (I) may be used, or the charge transporting material may be used in combination with another charge transporting material. it can. Other charge transport materials used include hydrazone compounds, pyrazoline compounds, styryl compounds, triphenylmethane compounds, oxadiazole compounds, carbazole compounds, stilbene compounds, enamine compounds, oxazole compounds, triphenylamine compounds, tetraphenylbenzidine Compounds, hole transport materials such as azine compounds and fluorenone compounds, anthraquinodimethane compounds, diphenoquinone compounds, stilbenequinone compounds, thiopyran dioxide compounds,
Various materials such as an oxadiazole compound, a perylenetetracarboxylic acid compound, a fluorenylidenemethane compound, an anthraquinone compound, an anthrone compound, and an electron transport material such as a cyanovinyl compound can be used.

Examples of the solvent used for forming the charge transport layer include aromatic solvents such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, methanol, and the like.
Ethanol, alcohols such as isopropanol, ethyl acetate, esters such as ethyl cellosolve, carbon tetrachloride, carbon tetrabromide, chloroform, dichloromethane, halogenated hydrocarbons such as tetrachloroethane, tetrahydrofuran, ethers such as dioxane, dimethylformamide,
Dimethyl sulfoxide, diethylformamide and the like can be mentioned. These solvents may be used alone or in combination of two or more.

When the photosensitive layer is of a laminated type, the application of the charge transport layer and the charge generation layer can be carried out using various coating apparatuses such as known ones. Specifically, various coating methods such as a dip coating method, a spray coating method, a spinner coating method, a blade coating method, a roller coating method, and a wire bar coating method can be used.

In the photosensitive layer of the present invention, in the case of lamination, especially in the charge transport layer, an additive for improving film formability or flexibility, an additive for suppressing accumulation of residual potential, and the like.
Well-known additives may be contained.

Specific examples of these compounds include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, o-ter-phenyl, m-ter-phenyl, p-ter-phenyl, diethyl biphenyl, hydrogenated t-phenyl, Plasticizers such as diisopropylbiphenyl, benzylbiphenyl, diisopropylnaphthalene, dibenzofuran, 9,10-dihydroxyphenanthrene, chloranil, tetracyanoquinodimethane, tetracyanoethylene, trinitrofluorenone, dicyanobenzoquinone, tetrachlorophthalic anhydride, 3,5 -Electron-withdrawing sensitizers such as dinitrobenzoic acid and cyanovinyl compounds, and sensitizers such as methyl violet, rhodamine B, cyanine dyes, pyrylium salts and thiapyrylium salts can be used.

The larger the amount of the plasticizer added, the more the internal stress of the layer is reduced. Therefore, when the photosensitive layer is formed by laminating the charge transport layer and the charge generation layer, the charge transport layer and the charge generation layer Is improved, and in the case of a single layer type, the adhesiveness between the photosensitive layer and the support is improved. However, if the amount is too large, problems such as a decrease in mechanical strength and a decrease in sensitivity occur. Therefore, 1 to 100 parts by weight, preferably 5 to 80 parts by weight, more preferably 10 to 100 parts by weight with respect to 100 parts by weight of the charge transporting material.
It is desirable to use about 50 parts by weight. The amount of the sensitizer to be added is preferably 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably about 0.5 to 8 parts by weight based on 100 parts by weight of the charge transporting material. .

Further, a photosensitive layer in the photosensitive member of the present invention,
In particular, an antioxidant may be added to the charge transport layer for the purpose of preventing ozone deterioration. Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, hydroquinone, spirochroman, spiroidanone, hydroquinoline and derivatives thereof, organic phosphorus compounds, organic sulfur compounds and the like.

The more the amount of the antioxidant added, the better the adhesion. However, if the amount is too large, problems such as a decrease in mechanical strength and the sensitivity occur. If the amount is too small, a sufficient effect of antioxidation is obtained. I can't. Therefore, 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight, per 100 parts by weight of the charge transporting material.
It is desirable to use about 3 to 20 parts by weight, more preferably about 3 to 20 parts by weight. When the antioxidant and the plasticizer are used in combination, the total amount of the additives is 1 to 120 parts by weight, preferably 5 to 120 parts by weight.
100 parts by weight, more preferably about 10 to 80 parts by weight. When the solubility of the plasticizer or the antioxidant is low or the melting point is high, crystal precipitation is caused or the adhesiveness is not improved so much.
It is preferable to use a compound having a temperature of 00 ° C. or lower.

The photoreceptor of the present invention may have a conductive layer provided between the support and the undercoat layer. As the conductive layer,
Metals such as aluminum, iron, nickel, etc. dispersed in a resin, or metal oxides such as conductive tin oxide, titanium oxide, antimony oxide, zirconium oxide, and ITO (indium, tin oxide solid solution) Those dispersed therein are preferably used.

Further, the photoreceptor of the present invention may have a surface protective layer provided on the photosensitive layer. The thickness of the surface protective layer is desirably 5 μm or less. As the material used for the surface protective layer, a polymer such as an acrylic resin, a polyaryl resin, a polycarbonate resin, a urethane resin, a thermosetting resin, a photocurable resin, or a low-resistance substance such as tin oxide or indium oxide is dispersed. Those that have been used can be used. Further, an organic plasma polymerized film may be used as the surface protective layer. The organic plasma polymerized film is appropriately formed of oxygen, nitrogen, halogen, Group 3 of the periodic table as needed,
It may contain Group 5 atoms.

Next, the case where the benzimidazole compound represented by the general formula (I) is used as a material for an organic electroluminescence device will be described.

FIGS. 1 to 4 schematically show an organic electroluminescent device according to the present invention. In the figure, reference numeral (1) denotes an anode, on which an organic hole injecting and transporting layer (2), an organic light emitting layer (3) and a cathode (4) are sequentially laminated. The hole injection transport layer contains the benzimidazole compound represented by the above general formula (I).

In FIG. 2, (1) is an anode, on which an organic hole injecting and transporting layer (2) and an organic light emitting layer (3), an organic electron injecting and transporting layer (5) and a cathode (4) are provided. The organic hole injecting / transporting layer or the organic light emitting layer contains a benzimidazole compound represented by the above general formula (I).

In FIG. 3, (1) is an anode, on which an organic light emitting layer (3), an organic electron injection / transport layer (5), and a cathode (4) are sequentially laminated. The organic light emitting layer contains the benzimidazole compound represented by the above general formula (I).

In FIG. 4, (1) denotes an anode, on which an organic light emitting layer (3) and a cathode (4) are sequentially laminated, and an organic light emitting material ( 6) and a charge transport material (7), and a benzimidazole compound represented by the above general formula (I) is used as the charge transport material.

The anode (1) and the cathode (4) are connected by a lead wire (8), and a voltage is applied to the anode (1) and the cathode (4). (3) emits light.

For the organic light emitting layer, the organic hole injecting / transporting layer, and the organic electron injecting / transporting layer, if necessary, a known optical substance, a light emitting auxiliary material, and a charge transporting material for transporting carriers can be used.

The specific benzimidazole compound represented by the general formula (I) has a small ionization potential and a large hole-transporting ability. Therefore, the light-emission starting voltage required for causing the organic electroluminescence device of the present invention to emit light is as follows. It is considered that the light emission may be low, which allows stable light emission for a long time. When the benzimidazole compound is used as an organic luminous body, it is considered that the function of the benzoimidazole compound itself as a luminous body and the thermal stability contribute.

Anode of organic electroluminescence element
As the conductive material used as (1), those having a work function of more than 4 eV are preferable, and carbon, aluminum, vanadium, iron, cobalt, nickel, copper, zinc,
Tungsten, silver, gold, platinum and their alloys,
Tin oxide, indium oxide, antimony oxide, zinc oxide,
A conductive metal compound such as zirconium oxide and an organic conductive resin such as polythiophene and polypyrrole are used.

The metal forming the cathode (4) is preferably a metal having a work function smaller than 4 eV.
Calcium, tin, lead, titanium, yttrium, lithium, gadolinium, ytterbium, ruthenium, manganese and their alloys are used.

The anode and the cathode may be formed of two or more layers if necessary.

In the organic electroluminescence element, at least the anode (1) or the cathode (4) needs to be a transparent electrode so that light emission can be seen. At this time, if a transparent electrode is used for the cathode, the transparency is easily impaired, so that the anode is preferably a transparent electrode.

When forming a transparent electrode, on a transparent substrate,
Using a conductive material as described above, a device such as vapor deposition, sputtering, or a method such as a sol-gel method or a method of dispersing and applying in a resin or the like is used to secure desired translucency and conductivity. I just need.

The transparent substrate is not particularly limited as long as it has an appropriate strength, is not adversely affected by heat due to vapor deposition or the like during the production of the organic electroluminescence element, and is transparent as long as it is transparent. It is also possible to use a glass substrate, a transparent resin such as polyethylene, polypropylene, polyethersulfone, polyetheretherketone, and the like. As a transparent electrode formed on a glass substrate, commercially available products such as ITO and NESA are known, but these may be used.

An example of the organic electroluminescence device of the present invention will be described with reference to a structure (FIG. 1) in which a benzimidazole compound is used in an organic hole injection / transport layer.

First, an organic hole injecting and transporting layer (2) is formed on the above-mentioned anode (1). The organic hole injecting and transporting layer (2) may be formed by vapor deposition of the benzimidazole compound represented by the general formula (I), or may be formed by dissolving the benzimidazole compound in a solution or a suitable resin. The formed liquid may be formed by dip coating or spin coating.
When formed by vapor deposition, the thickness is usually 1 to 500 nm
In the case of forming by a coating method, the thickness may be about 5 to 1000 nm. It is necessary to increase the applied voltage for emitting light as the thickness of the formed film increases, and thus the luminous efficiency is poor and the organic electroluminescent element is likely to be deteriorated.
In addition, when the film thickness is reduced, the luminous efficiency is improved, but the breakdown is easy and the life of the organic electroluminescent element is shortened.

The compounds of the general formula (I) can be used in combination with other charge transporting materials. For example, phthalocyanine compounds, naphthalocyanine compounds, porphyrin compounds, oxadiazole, triazole, imidazole,
Imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acylhydrazone, polyarylalkane, stilbene, butadiene, benzidine-type triarylamine, diamine-type triarylamine, and derivatives thereof, and Polymer materials such as polyvinyl carbazole, polysilane, and conductive polymers can be used, but they also have an excellent hole-injecting effect on the photosensitive layer or the luminescent substance, and the electrons of excitons generated in the luminescent layer Any compound can be used as long as it is a compound that prevents migration to the injection layer or the electron transport material and has excellent thin film forming ability.

An organic light emitting layer is formed on the organic hole injecting and transporting layer (2). As the organic luminescent material used for the organic luminescent layer and the luminescent auxiliary material, known materials can be used,
For example, epidolidine, 2,5-bis (5,7-di-t-pentyl-2-benzooxazolyl) thiophene,
2 ′-(1,4-phenylenedivinylene) bisbenzothiazole, 2,2 ′-(4,4′-biphenylene) bisbenzothiazole, 5-methyl-2- {2- (4- (5-methyl- 2-benzoxazolyl) phenyl) vinyl} benzoxazole, 2,5-bis (5-methyl-2-benzooxazolyl) thiophene, anthracene, naphthalene, phenanthrene, pyrene, chrysene, perylene, perinone, 1.4 -Diphenylbutadiene, tetraphenylbutadiene, coumarin, acridine, stilbene, 2-
(4-biphenyl) -6-phenylbenzoxazole,
Aluminum trisoxine, magnesium bisoxin, bis (benzo-8-quinolinol) zinc, bis (2-
Methyl-8-quinolinolate) aluminum oxide, indium trisoxine, aluminum tris
(5-methyloxin), lithium oxine, gallium trisoxin, calcium bis (5-chlorooxin),
Examples include polyzinc-bis (8-hydroxy-5-quinolinolyl) methane, dilithium epindridione, zinc bisoxin, 1,2-phthaloperinone, 1,2-naphthaloperinone, and tris (8-hydroxyquinoline) aluminum complex. Can be.

Further, general fluorescent dyes such as a fluorescent coumarin dye, a fluorescent perylene dye, a fluorescent pyran dye, a fluorescent thiopyran dye, a fluorescent polymethine dye, a fluorescent mesocyanine dye, a fluorescent imidazole dye and the like can also be used. Among them, particularly preferred are chelated oxinoid compounds.

The organic light-emitting layer may have a single-layer structure of the above-described light-emitting substance, or may have a multi-layer structure in order to adjust characteristics such as emission color and emission intensity. Further, two or more kinds of light-emitting substances may be mixed or the light-emitting layer may be doped.

The organic light emitting layer (3) may be formed by vapor deposition of the above light emitting substance, or by dip coating or spin coating a solution in which the light emitting substance is dissolved or a solution in which a suitable resin is dissolved. May be formed. In addition, the general formula (I)
May be used as the luminescent substance.

The thickness is usually 1 to 500 nm when formed by the vapor deposition method, and 5 to 1 nm when formed by the coating method.
It may be formed to about 000 nm. It is necessary to increase the applied voltage for emitting light as the thickness of the formed film increases, and thus the luminous efficiency is poor and the organic electroluminescent element is likely to be deteriorated. In addition, when the film thickness is reduced, the luminous efficiency is improved, but the breakdown is easy and the life of the organic electroluminescent element is shortened.

Next, the above-mentioned cathode is formed on the organic light emitting layer.

As described above, the organic hole injecting and transporting layer was formed on the anode (1).
(2) The organic light emitting layer (3) and the cathode (4) are sequentially laminated to form an organic luminescence device. Transport layer
(2) and the anode (1) are sequentially laminated, or on the anode (1),
Organic light emitting layer (3), organic electron injection / transport layer (5), and cathode
(4) are sequentially laminated (FIG. 3), an organic hole injecting and transporting layer (2), an organic light emitting layer (3), and an organic electron injecting and transporting layer are formed on the anode (1).
(5) and the cathode (4) are sequentially laminated (Fig. 2).
Of course, the organic electron injecting and transporting layer (5), the organic light emitting layer (3), and the anode (4) may be sequentially laminated on (4).

When the electron injection / transport layer is formed on the light emitting layer (3) as shown in FIG.
For example, fluorenone, anthraquinodimethane, diphenoquinone, stilbenequinone, thiopyran dioxide,
There are oxadiazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinone, anthrone and their derivatives, but they have the ability to transport electrons and have an excellent electron injection effect on the light-emitting layer or light-emitting substance. The compound is not limited thereto, as long as it is a compound that prevents excitons generated in the light emitting layer from moving to the hole injection layer or the hole transport material and has excellent thin film forming ability. Also,
Sensitization can also be achieved by adding an electron accepting substance or an electron donating substance to the charge transporting material.

Further, the hole injecting / transporting layer separates the hole injecting function and the hole transporting function from each other,
It may have a two-layer structure. In this case, it is preferable to use the benzimidazole compound of the present invention represented by the general formula (I) for the hole injection layer. The electron injecting and transporting layer may have a two-layer structure of an electron injecting layer and an electron transporting layer by separating the electron injecting and electron transporting functions.

A pair of transparent electrodes, ie, a cathode and an anode, are formed by using a suitable lead wire such as a nichrome wire, a gold wire, a copper wire, or a platinum wire for each electrode.
(8) is connected, and the organic luminescence device emits light by applying an appropriate voltage (Vs) to both electrodes.

The organic electroluminescence element of the present invention is applicable to various display devices, display devices, and the like.

Hereinafter, the present invention will be described by way of examples. In the examples, “parts” means “parts” unless otherwise specified.
Represents "parts by weight".

Synthesis Example 1 (Synthesis of Compound (25)) Compound (A) represented by the following chemical formula was placed in a 50 ml three-necked flask equipped with a water-cooled condenser.

Embedded image 1.55 g (0.005 mol) of a compound (B) represented by the following chemical formula;

Embedded image 4.0 g (0.01 mol), 4.2 g of anhydrous potassium carbonate, 0.85 g of copper powder, 0.17 g of 18-crown-6, and 10 ml of o-dichlorobenzene were mixed and reacted at a reflux temperature for 24 hours. . The reaction product was extracted with 200 ml of dichloromethane, the insoluble matter was removed by filtration, and the mixture was concentrated to dryness. This was purified by column chromatography (carrier; silica gel, eluent: developed with toluene / n-hexane = 1/2) to obtain 1.45 g of the desired compound (25) (yield 35.0%). The melting point was 185-186 ° C. In addition, when the molecular formula was analyzed using a CHN analyzer, the following results were obtained. Molecular formula: C ₅₈ H ₄₈ N ₆ Calculated value (%) C: 84.05%, H: 5.80%, N: 1
0.14% Analysis value (%) C: 84.12%, H: 5.76%, N: 1
0.12%

Application of Electrophotographic Photoreceptor to Charge Transport Material Example 1 Trisazo compound represented by the following formula (C):

Embedded image 0.45 part and 0.45 part of a polyester resin (Vylon 200; manufactured by Toyobo Co., Ltd.) were dispersed together with 50 parts of cyclohexanone by a sand mill. The resulting dispersion of the trisazo compound was applied on an aluminum drum of 80φ by a dip coating method so that the dry film thickness became 0.3 g / m, and then dried.

On the charge generation layer thus obtained, 50 parts of a benzimidazole compound (9) and a polycarbonate resin (Panlite K-1300; manufactured by Teijin Chemicals Ltd.)
A solution prepared by dissolving 50 parts in 400 parts of 1,4-dioxane was applied to a dry film thickness of 20 μm, and dried to form a charge transport layer. Thus, an electrophotographic photoreceptor having two photosensitive layers was obtained.

The photoreceptor thus obtained was subjected to a commercially available electrophotographic copying machine (EP-5400; manufactured by Minolta Camera Co., Ltd.).
Corona charging at −6 Kv, initial surface potential Vo (V), exposure amount E1 / 2 (lux · se) required to reduce initial potential to １ ／
c) Decay rate DD of initial potential when left in the dark for 1 second
R1 (%) was measured.

Examples 2 to 4 In the same manner as in Example 1, but having the same constitution, except that the benzimidazole compound (9) used in Example 1 was replaced with the benzimidazole compounds (10), (11), and ( 1
Photoreceptors using each of 2) were prepared. With respect to the photoreceptor thus obtained, Vo, E1 / 2,
DDR1 was measured.

Example 5 Bisazo compound represented by the following general formula (D)

Embedded image 0.45 parts, polystyrene resin (molecular weight 40000)
45 parts were dispersed together with 50 parts of cyclohexane by a sand mill.

The obtained dispersion of the bisazo compound was washed with 80
It was applied on a φ aluminum drum so that the dry film thickness was 0.3 g / m, and then dried.

On the charge generation layer thus obtained, 50 parts of a benzimidazole compound (14) and 50 parts of a polyarylate resin (U-100; manufactured by Unitika) were added in 1,
A solution dissolved in 400 parts of 4-dioxane has a dry film thickness of 2
It was applied to a thickness of 5 μm and dried to form a charge transport layer. Thus, an electrophotographic photosensitive member having a two-layer photosensitive layer was produced.

Examples 6 to 8 In the same manner as in Example 5, but having the same constitution, except that the benzimidazole compound (14) used in Example 5 was replaced with the benzimidazole compound (25), (27),
Photoconductors each using (30) were produced. With respect to the photoreceptor thus obtained, Vo, E1 were obtained in the same manner as in Example 1.
/ 2, DDR1 was measured.

Example 9 Polycyclic quinone pigment represented by the following formula (E):

Embedded image 0.45 parts, polycarbonate resin (Panlite K-1
3000: Teijin Chemicals Ltd.) 0.45 part of dichloroethane 5
It was dispersed by a sand mill together with 0 parts. The obtained dispersion of the polycyclic quinone pigment was placed on an aluminum drum of 80φ,
The coating was applied so that the dry film thickness became 0.4 g / m, and then dried. A solution prepared by dissolving 60 parts of a benzimidazole compound (31) and 50 parts of a polyarylate resin (U-100; manufactured by Unitika) in 400 parts of 1,4-dioxane was dried on the charge generation layer thus obtained. It was applied so as to have a thickness of 18 μm, and dried to form a charge transport layer. Thus, an electrophotographic photosensitive member having a two-layer photosensitive layer was produced.

Examples 10 to 11 In the same manner as in Example 10, but having the same constitution, except that the benzimidazole compound (31) used in Example 10 was replaced with the benzimidazole compounds (44) and (49)
Were prepared respectively. With respect to the photoreceptor thus obtained, Vo, E1 / 2, and DD were obtained in the same manner as in Example 1.
R1 was measured.

Example 12 0.45 part of titanyl phthalocyanine, butyral resin
(BX-1; manufactured by Sekisui Chemical Co., Ltd.) was dispersed in a sand mill together with 0.45 part of dichloroethane. The dispersion of the obtained phthalocyanine pigment was dried on an alumite drum of 80φ by a dip coating method to a dry film thickness of 0.3.
After coating to a thickness of μm, it was dried. On the charge generation layer thus obtained, 50 parts of a benzimidazole compound (59) and a polycarbonate resin (PC-
Z: manufactured by Mitsubishi Gas Chemical Company) 50 parts was 1,4-dioxane 40
The solution dissolved in 0 parts was applied so as to have a dry film thickness of 18 μm to form a charge transport layer. Thus, an electrophotographic photosensitive member having a two-layer photosensitive layer was produced. Vo, E1 / 2 and DDR1 of the photoreceptor thus obtained were measured in the same manner as in Example 1.

Example 13 50 parts of copper phthalocyanine and 0.2 parts of tetranitrocopper phthalocyanine were dissolved in 500 parts of 98% concentrated sulfuric acid with sufficient stirring, and the mixture was poured into 5000 parts of water. The conductive material composition was deposited. The precipitate is filtered, washed with water, and dried under reduced pressure.
Dried at 0 ° C.

10 parts of the photoconductive composition thus obtained was mixed with 22.5 parts of a thermosetting acrylic resin (Acrydic A405; manufactured by Dainippon Ink) and a melamine resin (Super Beckamine J820; manufactured by Dainippon Ink) 7 0.5 part and 15 parts of the benzimidazole compound (63) were placed in a ball mill pot together with 100 parts of a mixed solvent obtained by mixing methyl ethyl ketone and xylene in the same amount, and dispersed for 48 hours to prepare a photosensitive coating solution. The photosensitive layer having a thickness of about 15 μm was formed by spray coating on an alumite drum of 80φ and drying. Thus, a single-layer type photoreceptor was produced. The photoreceptor thus obtained was subjected to the same method as in Example 1 except that corona charging was performed at +6 Kv, and Vo, E1 / 2,
DDR1 was measured.

Example 14 In the same manner as in Example 13, with the same constitution, except that the benzimidazole compound (63) used in Example 13 was replaced with the benzimidazole compounds (67) and (70)
Were prepared respectively. With respect to the photoreceptor thus obtained, Vo, E1 / 2, D
DR1 was measured.

Vo of the photoreceptors obtained in Examples 1 to 15,
Table 1 summarizes the measurement results of E1 / 2 and DDR1.

[0109]

[Table 1]

As can be seen from Table 1, the photoreceptor of this example has a sufficient charge retention ability even in a laminated type or a single-layer type, and the dark decay rate is small enough to be usable as a photoreceptor. Is also excellent.

Further, a commercially available electrophotographic copying machine (EP-3)
50Z; manufactured by Minolta Co., Ltd.).
Even when 0 copies were made, clear images were obtained in the initial and final images with excellent gradation and no change in sensitivity. It can be seen that the photoreceptor of this embodiment has stable repetition characteristics.

Example 16 Application to Organic Electroluminescence Device Example 16 A thin film having a thickness of 50 nm was formed by vapor deposition of a benzimidazole compound (9) as an organic hole injecting and transporting layer on an indium tin oxide coated glass substrate. Next, aluminum trisoxine was deposited as an organic light emitting layer by evaporation to a thickness of 50 nm.
A thin film was formed to have a thickness of. Next, a thin film was formed as a cathode by evaporation of magnesium to a thickness of 200 nm. Thus, an organic electroluminescence device was manufactured.

Examples 17 to 19 In Example 16, the benzimidazole compound (9)
Instead of using a benzimidazole compound (1
Example 1 except that 1), (12), and (15) were used instead
An organic electroluminescent device was produced in exactly the same manner as in No. 6.

Example 20 A benzimidazole compound (24) was formed as an organic hole injecting and transporting layer on a glass substrate coated with indium tin oxide by evaporation to form a thin film having a thickness of 70 nm. Next, aluminum trisoxine was deposited as an organic light emitting layer by vapor deposition.
A thin film was formed so as to have a thickness of 0 nm. Next, the following oxadiazole compound (F) as an organic electron injection / transport layer;

Embedded image Was formed to a thickness of 50 nm by vapor deposition. Next, magnesium was vapor-deposited for 200 as a cathode.
A thin film was formed to a thickness of nm. Thus, an organic electroluminescence device was manufactured.

Examples 21 to 23 In Example 20, instead of using the compound (24), the benzimidazole compounds (28), (32),
An organic electroluminescent device was produced in exactly the same manner as in Example 20, except that (34) was used.

Example 24 A benzimidazole compound (37) was formed as an organic light-emitting layer on an indium tin oxide-coated glass substrate by evaporation to form a thin film having a thickness of 50 nm. Next, an oxadiazole compound (F) was deposited by evaporation as an organic electron injecting and transporting layer.
A thin film was formed so as to have a thickness of 0 nm. Next, Mg and Ag having an atomic ratio of 10: 1 were deposited as a cathode by evaporation.
A thin film was formed so as to have a thickness of 0 nm. Thus, an organic electroluminescence device was manufactured.

Example 25 A benzimidazole compound (48) was vacuum-deposited on a substrate of indium tin oxide-coated glass to obtain a hole injection layer having a thickness of 20 nm. Further, N, N'-diphenyl-N,
N '-(3-methylphenyl) -1,1'-biphenyl-
4,4′-Diamine was vacuum-deposited to obtain a hole transport layer having a thickness of 40 nm. Next, tris (8-hydroxyquinoline)
A thin film was formed by vapor deposition of an aluminum complex so as to have a thickness of 50 nm. Next, as a cathode, a thin film of 200 nm in thickness was formed by vapor deposition of Mg and Ag at an atomic ratio of 10: 1. Thus, an organic electroluminescence device was manufactured.

Example 26 On a substrate of indium tin oxide coated glass, N, N '
-Diphenyl-N, N '-(3-methylphenyl) -1,
1′-biphenyl-4,4′-diamine was vacuum-deposited to obtain a 60 nm-thick hole transport layer. Next, Tris (8
(Hydroxyquinoline) aluminum complex and benzimidazole compound (3) were formed in a ratio of 3: 1 by vacuum evaporation to form a light emitting layer having a thickness of 60 nm. Next, as a cathode, a thin film of 200 nm in thickness was formed by vapor deposition of Mg and Ag at an atomic ratio of 10: 1. Thus, an organic electroluminescence device was manufactured.

Example 27 A benzimidazole compound (57) was dissolved in dichloromethane on a substrate of indium tin oxide-coated glass.
A hole injection layer having a thickness of 50 nm was obtained by spin coating. Further, a light emitting layer was formed by vapor deposition of a tris (8-hydroxyquinoline) aluminum complex to a thickness of 20 nm. Further, an electron injection layer having a thickness of 20 nm of the oxadiazole compound (F) was obtained by a vacuum evaporation method. next,
A thin film was formed by vapor deposition of Mg and Ag in a 10: 1 atomic ratio to a thickness of 200 nm as a cathode. Thus, an organic electroluminescence device was manufactured.

Examples 28 to 29 In Example 27, the benzimidazole compound (5
An organic electroluminescent device was produced in exactly the same manner as in Example 27, except that the benzimidazole compounds (59), (61) and (65) were used instead of 7).

Example 30 A benzimidazole compound (70), a tris (8-hydroxyquinoline) aluminum complex, and polymethyl methacrylate were dissolved in tetrahydrofuran at a ratio of 3: 2: 5 on an indium tin oxide-coated glass substrate. A light emitting layer having a thickness of 100 nm was obtained by spin coating.
Next, as a cathode, a thin film of 200 nm in thickness was formed by vapor deposition of Mg and Ag at an atomic ratio of 10: 1.
Thus, an organic electroluminescence (electroluminescence) device was produced.

Comparative Example 1 A benzimidazole compound (G) as an organic hole injecting and transporting layer on a substrate of indium tin oxide coated glass;

Embedded image Was formed into a thin film having a thickness of 50 nm by vapor deposition. Next, a thin film having a thickness of 50 nm was formed as an organic light emitting layer by vapor deposition of aluminum trisoxine. Next, a thin film was formed as a cathode by evaporation of magnesium to a thickness of 200 nm. Thus, an organic electroluminescence device was manufactured.

Evaluation The organic EL device obtained in each of Examples 16 to 30 and Comparative Example 1 was used as a glass electrode as an anode, and a light emission starting voltage and a maximum light emission luminance when a DC voltage was applied, and a light emission voltage at that time. Was measured. Table 2 summarizes the measurement results.

[0124]

[Table 2]

As can be seen from Table 2, the organic electroluminescence device of this example exhibited good light emission luminance even at a low potential. When the organic electroluminescent device of Example 25 of the present invention was continuously emitted at a current density of 1 mA / cm ² , stable emission was observed for 200 hours or more.

The organic electroluminescent device of the present invention achieves an improvement in luminous efficiency, luminous luminance and a long life, and is used together with a luminescent substance, a luminescent auxiliary material, a charge transport material, a sensitizer, The invention is not limited to resin, electrode material, and the like, and the element manufacturing method.

[0127]

According to the present invention, a novel benzimidazole compound having an excellent charge transporting ability is provided. By using the benzimidazole compound, the electrophotographic photoreceptor has excellent initial electrophotographic properties such as sensitivity, charge transport properties, initial surface potential, and dark decay rate, and has less fatigue due to repeated use. An organic electroluminescent device excellent in low durability was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one configuration example of an organic electroluminescence element of the present invention.

FIG. 2 is a schematic cross-sectional view of one configuration example of the organic electroluminescence element of the present invention.

FIG. 3 is a schematic cross-sectional view of one configuration example of the organic electroluminescence element of the present invention.

FIG. 4 is a schematic cross-sectional view of one configuration example of the organic electroluminescence element of the present invention.

[Explanation of symbols]

1: anode, 2: hole injection / transport layer, 3: organic light emitting layer, 4:
Cathode, 5: electron injection transport layer, 6: organic light emitting material, 7: charge transport material, 8: lead wire

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/22 H05B 33/22 D (72) Inventor Keiichi Furukawa 2-3 Azuchicho, Chuo-ku, Osaka-shi, Osaka No. 13 Osaka International Building Minolta Co., Ltd. F-term (reference) 2H068 AA20 AA21 BA14 BA16 GA18 3K007 AB00 AB02 AB06 BB00 CA01 CA05 CB01 DA00 DB03 EB00 FA01 4C063 AA03 AA05 BB01 BB02 CC92 DD26 EE10

Claims (5)

[Claims] 1. A novel benzimidazole compound represented by the following general formula (I): (Wherein, A represents an arylene group or a heterocyclic group which may be bonded by a linking group; Ar ₁ and Ar ₂ each represent an aryl group or a heterocyclic group which may have a substituent; R ₁ and R ₂ is each independently a hydrogen atom, an alkyl group,
Represents an alkoxy group or a halogen atom). 2. A benzimidazole compound represented by the following general formula (II): (Wherein A represents an arylene group or a heterocyclic group which may be bonded by a linking group; R ₁ and R ₂ are each independently
A hydrogen atom, an alkyl group, an alkoxy group or a halogen atom) and a halogen compound represented by the following general formula (III): (Wherein, Ar ₁ and Ar ₂ each represent an aryl group or a heterocyclic group which may have a substituent; X represents a halogen atom). A method for producing an imidazole compound. 3. A hole transport material comprising the benzimidazole compound according to claim 1. 4. An organic electroluminescent device comprising a light emitting layer or a plurality of organic compound thin layers including a light emitting layer between a pair of electrodes, wherein at least one layer contains the benzimidazole compound according to claim 1. Organic electroluminescent element. 5. An electrophotographic photosensitive member comprising a charge generation material and a charge transport material on a conductive support,
An electrophotographic photosensitive member, wherein the charge transporting material comprises the hole transporting material according to claim 3.