JP4763306B2 - Anthracene compounds - Google Patents

Description

  The present invention relates to an anthracene compound and a method for producing the anthracene compound, and more particularly to an anthracene compound suitable as a charge transport material and useful as an organic photoconductor and a method for producing the anthracene compound.

  In recent years, there has been a remarkable development in information processing system machines using electrophotography. In particular, laser printers and digital copying machines that convert information into digital signals and record information using light have significantly improved print quality and reliability. Furthermore, they have been applied to laser printers or digital copiers capable of full-color printing by fusing with high-speed technology.

  Photoreceptors used in these electrophotographic laser printers and digital copying machines generally use organic photosensitive materials (OPC) for reasons of cost, productivity, and pollution-free property. Widely applied.

  By the way, the layer structure of the OPC photoreceptor is roughly classified into a single layer type and a function separation type laminated structure. The first practical OPC, the PVK-TNF charge transfer complex type photoreceptor, was the former single layer type. On the other hand, in 1968, a PVK / a-Se laminated photoreceptor was independently invented by Hayashi and Regensburger, and later called 1977 Melz et al. And 1978 Schlosser called an organic pigment dispersion layer and an organic low molecular weight dispersion polymer layer. A multi-layer photoconductor in which all photosensitive layers are made of organic materials has been announced. These are functionally separated from the concept of a charge generation layer (CGL) that absorbs light and generates charges, and a charge transport layer (CTL) that injects and transports charges generated by CGL and neutralizes surface charges. Also called a mold-laminated photoconductor.

  This development has dramatically improved sensitivity and durability compared to single-layer photoconductors. In addition, since materials having different functions, which are called charge generation materials (CGM) and charge transport materials (CTM), can be individually designed, the selection range of these materials has been greatly increased. For these reasons, the function-separated laminated photoconductor has the mainstream layer structure of the current OPC photoconductor.

  The mechanism of electrostatic latent image formation in the function-separated type photoconductor is that when the photoconductor is charged and then irradiated with light, the light passes through the charge transport layer and is absorbed by the charge generation material in the charge generation layer to generate a charge. . Charges generated thereby are injected into the charge transport layer at the interface between the charge generation layer and the charge transport layer, and further moved through the charge transport layer by an electric field, thereby forming an electrostatic latent image by canceling the surface charge of the photoreceptor. Is.

  In recent years, due to the reduction in the diameter of the photosensitive member accompanying the increase in the speed of the electrophotographic apparatus or the downsizing of the apparatus, the high-speed response and stability of the photosensitive member have become even more important issues. Commercially available charge transport materials include 1,1-bis (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene (see, for example, Patent Document 1), 5- [4- (N , N-di-p-tolylamino) benzylidene] -5H-dibenzo [a, d] cycloheptene (see, for example, Patent Document 2), 9-methylcarbazole-3-aldehyde 1,1-diphenylhydrazone, pyrene-1-aldehyde 1,1-diphenylhydrazone (see, for example, Patent Document 3), 4′-bis (4-methylphenyl) amino-α-phenylstilbene, N, N′-diphenyl-N, N′-bis (3-methylphenyl) )-[1,1′-biphenyl] -4,4′-diamine, 9,9-dimethyl-2- (di-p-tolylamino) fluorene, and the like.

  A general charge transport layer is a solid solution film of about 10 to 30 μm in which these low molecular charge transport materials are molecularly dispersed in a binder resin. As the binder resin, bisphenol-based polycarbonate resin, polyarylate resin, or a copolymer of these with other resins is used in most electrophotographic photoreceptors. However, these charge transport materials are not responsive enough to accommodate future faster process speeds.

On the other hand, there is known a document showing molecular design guidelines regarding high-speed response (high mobility) of these charge transport materials (see, for example, Non-Patent Document 1). In this non-patent document, a phenylamine group (> N-phenyl) is used as a sensitive group, and there is a clear correlation between the number and mobility, and the higher the number of sensitive groups in the molecule, the higher the mobility. It is stated.
Japanese Patent Laid-Open No. 62-030255 JP-A-63-225660 JP 58-159536 A Journal of Electrophotographic Society, 25 (3), 16 (1986)

  The present invention has been made in view of the above-described circumstances, and provides an anthracene compound useful as an organic photoconductor and a method for producing the same in order to obtain high-speed response and high photosensitivity. The purpose is to support high-speed photography.

In order to solve the above-mentioned problems, the invention described in claim 1 has an anthracene compound represented by the following general formula (1) as the main feature.
(Compounds of general formula _{(1), R 1, R} 2 is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic hydrocarbon group, may be the same or different. Also, R ₁ , R ₂ may be bonded to each other to form a substituted or unsubstituted heterocyclic group containing a nitrogen atom, R ₃ is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted Or an unsubstituted aromatic hydrocarbon group and a halogen atom are represented, and n represents the integer of 1-4.)

The anthracene compound represented by the general formula (1) can be produced by reacting 9,10-dibromoanthracene of the following general formula (2) with a boron compound of the following general formula (3). .
(In the general formula (2) and the general formula _{(3), R 1, R} 2, R 3 and n are the same groups, represents an integer.)

  According to the present invention, the anthracene compound represented by the general formula (1) is novel and functions effectively as a photoconductive material as described above. Further, it is preferably used as a charge transport material for a photosensitive layer of an electrophotographic photoreceptor, and particularly useful as a charge transport material in a so-called function-separated type photosensitive layer in which a charge generation layer and a charge transport layer are divided into two layers. It is. Furthermore, these novel anthracene compounds can be produced by the production method of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
According to the present invention, a triphenylene compound represented by the general formula (1) is provided, and the 9,10-dibromoanthracene of the general formula (2) is reacted with the boron compound of the general formula (3). A method for producing the anthracene compound of the above general formula (1) is provided.

  As described above, the anthracene compound represented by the general formula (1) of the present invention is a novel compound, and the corresponding 9,10-dibromoanthracene represented by the general formula (2) and the general formula (3). It can manufacture by making the boron compound represented by these react.

  In order to produce these, the mixture of the raw material of the said General formula (2) and the said General formula (3) or its salt using metal palladium in presence or absence of a base is about 100-250 degreeC. It can manufacture by attaching | subjecting to the coupling reaction made to react in.

  The solvent used in this reaction is not particularly limited as long as it does not adversely influence the reaction. For example, water; alcohols such as methanol, ethanol and propanol; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as methylene chloride, chloroform and dichloroethane; halogenated aromatic carbon such as dichlorobenzene Hydrogens; ethers such as dioxane, tetrahydrofuran, and anisole; esters such as ethyl acetate and butyl acetate; ketones such as acetone and methyl ethyl ketone; nitriles such as acetonitrile; N, N-dimethylformamide and N, N-dimethyl Examples include amides such as acetamide; sulfoxides such as dimethyl sulfoxide, and these solvents may be used in combination.

  Examples of basic substances include potassium acetate, potassium carbonate, sodium bicarbonate, sodium carbonate, triethylamine and the like. The amount of use is specifically 1 to 3 moles. Examples of the metal palladium include inorganic palladium salts such as palladium chloride; organic palladium salts such as palladium acetate; tetrakis (triphenylphosphine) palladium (0), bis (triphenylphosphine) palladium (II) chloride, 1,1′- And organic palladium complexes such as bis (diphenylphosphino) ferrocenepalladium (II) dichloride. Specifically, the amount used is 0.001 to 0.5 times mol.

  Specific examples of the alkyl group in the description of the general formula include methyl group, ethyl group, propyl group, butyl group, hexyl group, and undecanyl group. In addition, aromatic hydrocarbon groups include aromatic rings such as benzene, biphenyl, naphthalene, anthracene, fluorene and pyrene, and aromatic heterocyclic groups such as pyridine, quinoline, thiophene, furan, oxazole, oxadiazole and carbazole. Can be mentioned.

These substituents include those exemplified in the above specific examples of alkyl groups, alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group, or halogen atoms of fluorine atom, chlorine atom, bromine atom and iodine atom. Atoms, the aromatic hydrocarbon groups, and heterocyclic groups such as pyrrolidine, piperidine, piperazine and the like can be mentioned. Further, when R ₁ and R ₂ are bonded to each other to form a heterocyclic group containing a nitrogen atom, the heterocyclic group is a condensed heterocyclic ring in which an aromatic hydrocarbon group is condensed with a pyrrolidino group, piperidino group, piperazino group or the like. The group can be mentioned.

  The novel anthracene compound represented by the general formula (1) of the present invention is extremely useful as a photoconductive material in an electrophotographic photoreceptor. Further, the anthracene compound is particularly useful as a charge transport material in a so-called function-separated type photoreceptor using an organic pigment or an inorganic pigment as a charge generation material.

  Organic pigments for charge generation materials include CI Pigment Blue 25 (Color Index CI 21180), CI Pigment Red 41 (CI 21200), CI Acid Red 52 (CI 45100), CI Basic Red 3 (CI 45210), and carbazole skeleton. Azo pigments (described in JP-A-53-95033), azo pigments having a distyrylbenzene skeleton (described in JP-A-53-133445), azo pigments having a triphenylamine skeleton (JP-A-53 No. -132347), azo pigments having a dibenzothiophene skeleton (described in JP-A No. 54-21728), azo pigments having an oxadiazole skeleton (described in JP-A No. 54-12742), fluorenone Azo pigments having a skeleton (described in JP-A No. 54-22834), bis An azo pigment having a tilbene skeleton (described in JP-A No. 54-17733), an azo pigment having a distyryloxadiazole skeleton (described in JP-A No. 54-2129), an azo pigment having a distyrylcarbazole skeleton (Described in JP-A-54-14967), azo pigments such as azo pigments having a benzanthrone skeleton, for example, CI Pigment Blue 16 (CI 74100), Y-type oxotitanium phthalocyanine (JP-A 64-17066) ), A (β) -type oxotitanium phthalocyanine, B (α) -type oxotitanium phthalocyanine, I-type oxotitanium phthalocyanine (described in JP-A-11-21466), II-type chlorogallium phthalocyanine (Iijima et al., Nippon Chemical Co., Ltd.) 67th Annual Meeting, 1B4, 04 (1994)), V type Phthalocyanine-based pigments such as hydroxygallium phthalocyanine (Damon et al., Chemical Society of Japan 67th Spring Annual, 1B4, 05 (1994)), X-type metal-free phthalocyanine (US Pat. No. 3,816,118), C-Ibat Brown And perylene pigments such as Argo scarlet B (manufactured by Bayer), Insence scarlet R (manufactured by Bayer), and the like. These materials may be used alone or in combination of two or more. In addition, inorganic pigments such as selenium, selenium-tellurium, cadmium sulfide, and α-silicon can also be used.

  Hereinafter, the present invention will be described in detail with reference to examples.

[ Production Example 1]
Production of Boron Compound The boron compound (2) is obtained by a chemical reaction shown in the following chemical reaction formula (A).

In chemical reaction formula (A),
Bromo compound (i): terahydrofuran (dehydrated): 200 ml was added to 20 g (44 mmol), cooled to −70 ° C., and n-butyllithium (1.6 M) dissolved in n-hexane: 42 ml was added. Stir for hours. Thereafter, 13.72 g of trimethoxyborane (132 mmol) was gradually added dropwise and stirred for 6 hours.
After standing at room temperature, water was added, extracted with toluene, and washed with water. The dark yellow oil obtained by concentrating the organic layer under reduced pressure was subjected to silica gel column treatment [eluent: toluene / dichloromethane (1/1) vol] to give a yellow amorphous boron compound (ii): 18.20 g (98 .6%).

[Example 2]
Manufacture of anthracene compounds
In the chemical reaction formula (B),
9,10-dibromoanthracene (iii): 0.1 g (0.297 mmol)
Boron compound (ii): 0.374 g (0.4455 mmol)
K ₂ CO ₃ : 0.246 g
Tetrakis (triphenylphosphine)
Palladium (0): 0.205 g (0.1782 mmol)
DMF: 10ml
H ₂ O: 5 ml
o-Dichlorobenzene: 20 ml
And stirred at 95 ° C. for 7 hours. After cooling to room temperature, water was added, extracted with toluene, and washed with water. The dark yellow oily substance obtained by concentrating the organic layer under reduced pressure was subjected to silica gel column treatment [eluent: toluene / n-hexane (1/2) vol] to give yellow amorphous crystals represented by the following general formula (4). Anthracene compound (iv) of 0.236 g (yield: 86.1%) was obtained.

(The infrared absorption spectrum (KBr tablet method) of the anthracene compound (iv) of the general formula (4) is shown in FIG.

[Application example]
As a charge generation material, 500 parts of 0.5% tetrahydrofuran solution of a fluorenone-based bisazo pigment represented by the following general formula (5) and a polyester resin [Byron 200 manufactured by Toyobo Co., Ltd.] was pulverized and mixed in a ball mill. The dispersion was applied onto an aluminum vapor-deposited polyester film with a doctor blade and naturally dried to form a charge generation layer of about 0.5 μm.

Next, 1 part of a triphenylene compound represented by the above general formula (4) is dissolved as a charge transport material in a resin solution of 1 part of polycarbonate resin [Panlite K-1300 manufactured by Teijin Ltd.] and 8 parts of tetrahydrofuran, This solution was applied onto the charge transport layer with a doctor blade and dried at 80 ° C. for 2 minutes and then at 120 ° C. for 5 minutes to form a charge transport layer having a thickness of about 20 μm to prepare a photoreceptor.
Next, in order to investigate the transit time indicating the response characteristics of the multilayer electrophotographic photosensitive member thus obtained, an electrostatic copying paper test apparatus (type EPA8100 manufactured by Kawaguchi Electric Manufacturing Co., Ltd.) was used for this photosensitive member. The exposure amount that can be light-attenuated from −800 V to −100 V after 1 s with an exposure time of 33 ms is determined, and the value obtained by subtracting the exposure time of 33 ms from the time of reaching −150 V is defined as the transit time (tr). I did it. The result was tr = 12 ms.

[Comparative example]
When a photoreceptor was prepared and the tr measurement was performed by the same operation as in the application example for the amine compound represented by the following chemical formula (6) represented by the following structural formula, tr = 22 ms.

It is an infrared absorption spectrum figure of the anthracene compound of the present invention.

Claims (2)

An anthracene compound represented by the following general formula (1).
(Wherein, _{R 1} and R ₂ represents an aromatic hydrocarbon group having an alkyl group as a substituent, are the same. _{R 3} represents a hydrogen atom, n is an integer from 1 to 4 .) The anthracene compound according to claim 1, wherein the alkyl group is a methyl group.