JP5561077B2 - Novel arylamine dendrimer-like compound, production method thereof and use thereof - Google Patents

Description

  The present invention relates to a novel arylamine dendrimer-like compound, a method for producing the same, and an electronic device using the same.

  Organic EL elements are mainly divided into a light-emitting layer, a carrier transport layer that transports holes or electrons, two electrodes, a cathode and an anode, and other materials.

  As the material of the organic EL element, various low molecular weight materials and high molecular weight materials are used for the light emitting layer and the carrier transport layer. Especially, the low molecular weight material is excellent in terms of efficiency and life of the element. Therefore, many materials have been proposed and commercialized for mobile applications. However, the biggest problem of an organic EL element made of a low molecular material is the manufacturing cost, and as a solution, development of a coating material such as a polymer material is desired.

  As polymer coating materials, for example, poly (p-phenylene vinylene), polyalkylthiophene (see, for example, Patent Document 1), and polyfluorene-based conductive π-conjugated polymers are known.

  Further, PEDOT-PSS, polyarylamine, and the like have been proposed as hole injection (transport) materials. As polyarylamines, non-conjugated polymers having an arylamino group in the side chain (for example, see Patent Documents 2 to 6) and conjugated polymers having an arylamine structure in the main chain have been reported (for example, Patent Documents 7 to 8). reference).

  Regarding hole transfer, which is an important factor in the efficiency and lifetime of organic EL devices, hole transfer of non-conjugated arylamine polymers proceeds via hopping transport between molecules, whereas in conjugated arylamine polymers, In addition to via hopping transport in between, the holes can advantageously move along the main chain structure. Therefore, a conjugated arylamine polymer is particularly preferable in terms of efficiency.

  Furthermore, according to Patent Documents 7 to 8, it is reported that the device lifetime is improved by protecting the polymer terminal (for example, halogen atom, secondary amino group, etc.).

  As the polymer coating material, in addition to the various polymers as described above, a new organic EL technology using a dendrimer has been developed (for example, see Non-Patent Document 1). Since conventional polymers are linearly linked, it has been a disadvantage that they become difficult to dissolve in a solvent when the molecular weight is increased. However, dendrimers can be used by mixing a large amount of polymer light-emitting materials, so the coating properties are good. It becomes. It has been reported that a dendrimer having an arylamine as a constituent element also exhibits good solubility in an organic solvent (see, for example, Patent Document 9).

JP-A-3-230787 JP-A-8-54833 JP-A-8-259935 Japanese Patent Laid-Open No. 11-35687 JP-A-11-292828 Japanese Patent Laid-Open No. 13-98023 JP 2004-292882 A Special table 2001-527102 Special table 2009-512628 gazette

Dendritic polymer / highly functional world with multi-branched structure, 2005, pages 246-259

  Whether it is a conjugated arylamine polymer with a polymer end protected or an arylamine dendrimer, it does not reach the performance of organic EL devices made of low molecular weight materials, and further performance improvement is desired. ing.

  The present invention has been made in view of the above-described problems, and relates to a novel arylamine dendrimer-like compound that is superior in durability and luminous efficiency to conventional materials.

  As a result of intensive studies to solve the above problems, the present inventors have found that arylamine dendrimer-like compounds obtained by specific polymerization reactions are superior to conventional conjugated arylamine polymers in terms of luminous efficiency and durability. As a result, the present invention has been completed.

  That is, the present invention provides the following general formula (1)

(In the formula, Ar ¹ and Ar ² each independently represent an aromatic group having 6 to 60 carbon atoms which may have a substituent, and n represents an integer of 2 or more.)
And an arylamine polymer skeleton represented by the general formula (2)

(In the formula, Ar ³ represents an arylene group having 6 to 30 carbon atoms or a heteroarylene group having 3 to 30 carbon atoms, and R represents a binding site of the arylamine polymer skeleton represented by the general formula (1). )
An arylamine dendrimer-like compound characterized by having a structure in which an aromatic diamine which may have at least one kind of substituent represented by the above is repeatedly bonded, and a production method and use thereof.

In the compound represented by the general formula (1), Ar ¹ is not particularly limited as long as it is an aromatic group having 6 to 60 carbon atoms which may have a substituent. It is preferably any one of 3) to (6).

(In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group having 1 to 18 carbon atoms or an optionally substituted phenyl group, and m is an integer of 1 to 3) Represents).

Although R ^{1, R} 2, ^{R 3} and an alkyl group having 1 to 18 carbon atoms represented as ^{R 4,} or not particularly restricted but includes a phenyl group which may have a substituent group, include C 1-18 Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert -Pentyl group, cyclopentyl group, n-hexyl group, 2-ethylbutyl group, 3,3-dimethylbutyl group, cyclohexyl group, n-heptyl group, cyclohexylmethyl group, n-octyl group, tert-octyl group, 2-ethylhexyl Group, n-nonyl group, n-decyl group, trifluoromethyl group and the like, and as the phenyl group which may have a substituent, Phenyl group, tolyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, n-pentylphenyl group, isopentyl Phenyl group, neopentylphenyl group, tert-pentylphenyl group, cyclopentylphenyl group, n-hexylphenyl group, chlorophenyl group, bromophenyl group, fluorophenyl group, difluorophenyl group, methoxyphenyl group, acetylphenyl group, cyanophenyl group Methylthiophenyl group, methoxycarbonylphenyl group, N, N-dimethylaminophenyl group and the like.

In the compound represented by the general formula (1), Ar ² is not particularly limited as long as it is an aromatic group having 6 to 60 carbon atoms which may have a substituent. It is preferably any one of 7) to (12).

(In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ each independently have an alkyl group having 1 to 18 carbon atoms, or a substituent. A represents an integer of 0 to 5).
^{R 5, R 6, R 7} , R 8, R 9, R 10, R 11, an alkyl group having 1 to 18 carbon atoms represented as ^{R 12} and ^{R 13,} as a phenyl group which may have a substituent Although there is no particular limitation, examples represented as R ¹ , R ² , R ³ and R ⁴ can be given.

  The arylamine dendrimer-like compound of the present invention has the following general formula (13)

(In the formula, Ar ¹ and Ar ² are each independently an aromatic group having 6 to 60 carbon atoms which may have a substituent, X represents a halogen atom, and n represents an integer of 2 or more.)
And an arylamine polymer represented by the general formula (14)

(In the formula, Ar ³ represents an arylene group having 6 to 30 carbon atoms or a heteroarylene group having 3 to 30 carbon atoms.)
The aromatic diamine which may have at least one kind of substituent represented by the above can be produced by reacting in the presence of a palladium catalyst and a base.

In the arylamine polymer represented by the general formula (13), Ar ¹ and Ar ² are the same as described above.

In the polyhalogenated aromatic compound represented by the general formula (14), Ar ³ is not particularly limited as long as it is an arylene group having 6 to 30 carbon atoms or a heteroarylene group having 3 to 30 carbon atoms. However, examples of the arylene group include a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, an anthracenylene group, a phenanthrylene group, a fluorenylene group, a pyrenylene group, a chrysenylene group, and the like. Examples of the heteroarylene group include a thienylene group and a pyrrolylene group. N-substituted carbazolylene group and the like.

  Although it does not specifically limit as a palladium compound which can be used as a catalyst component of a palladium catalyst, For example, tetravalent palladium compounds (hexachloro palladium (IV) sodium tetrahydrate, hexachloro palladium (IV) potassium etc.) ) Divalent palladium compounds (palladium (II) chloride, palladium (II) bromide, palladium (II) acetate, palladium (II) acetylacetonate, dichlorobis (benzonitrile) palladium (II), dichlorobis (acetonitrile) Palladium (II), dichlorobis (triphenylphosphine) palladium (II), dichlorotetraammine palladium (II), dichloro (cycloocta-1,5-diene) palladium (II), palladium (II) trifluoroacetate, etc. , And zero-valent palladium compounds (tris (dibenzylideneacetone) dipalladium (0), tris (dibenzylideneacetone) dipalladium (0) chloroform complex, tetrakis (triphenylphosphine) palladium (0), etc.) Can do.

  The amount of the palladium compound used is not particularly limited, but in the reaction between the arylamine polymer represented by the general formula (1) and the aromatic diamine, the raw material arylamine polymer (in terms of number average molecular weight) In terms of palladium, it is usually in the range of 0.00001 to 20 mol%, and since an expensive palladium compound is used, it is usually preferably in the range of 0.001 to 5 mol%.

  In the method of the present invention, the ligand that can be used as a catalyst component of the palladium catalyst is not particularly limited, and any ligand that can coordinate to palladium, such as trialkylphosphines, aryl Examples include phosphines and carbene ligands.

  In the method of the present invention, trialkylphosphines that can be used as a catalyst component are not particularly limited. For example, triethylphosphine, tricyclohexylphosphine, triisopropylphosphine, tri-n-butylphosphine, Examples include isobutylphosphine, tri-sec-butylphosphine, tri-tert-butylphosphine and the like. Of these, tri-tert-butylphosphine is preferably used because of its particularly high reaction activity as a catalyst.

  In the method of the present invention, aryl phosphines that can be used as a catalyst component are not particularly limited, and examples thereof include triphenylphosphine, tri (o-tolyl) phosphine, and tri (m-tolyl). Phosphine, tri (p-tolyl) phosphine, 2,2′-bis (diphenylphosphino) -1,1′-binaphthyl (BINAP), trimesitylphosphine, diphenylphosphinoethane, diphenylphosphinopropane, diphenylphosphinoferrocene Etc.

  Examples of the carbene-based ligand include 1,3-bis (2,6-diisopropylphenyl) imidazol-2-ylidene hydrochloride.

  The amount of the ligand to be used is not particularly limited, but it may be used usually in the range of 0.01 to 10000 times mol of the palladium compound, and expensive trialkylphosphine, arylphosphine, carbene-based coordination. Since a child is used, it is preferably in the range of 0.1 to 10 moles relative to the palladium compound.

  The method for adding the palladium catalyst is not particularly limited, and it may be added to the reaction system alone as a catalyst component, or may be added in advance in the form of a complex comprising these catalyst components.

  The base is not particularly limited, and examples thereof include inorganic bases such as sodium and potassium carbonates, alkali metal alkoxides, and organic bases such as tertiary amines. Of these, preferred are alkali metal alkoxides such as sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, lithium-tert-butoxide, sodium-tert-butoxide, potassium-tert-butoxide, and the like. It may be added to the system as it is, or may be prepared in situ from an alkali metal, an alkali metal hydride or an alkali metal hydroxide and an alcohol and supplied to the reaction system. More preferably, a tertiary alkoxide such as lithium-tert-butoxide, sodium-tert-butoxide, potassium-tert-butoxide or the like is added to the reaction system as it is.

  The amount of the base used is not particularly limited. For example, in the reaction of the arylamine polymer represented by the general formula (1) and the aromatic diamine, preferably the halogen of the arylamine polymer added to the reaction system. If the post-treatment operation after the completion of the reaction is taken into consideration, the range of 1 to 5 times mol is more preferable.

  The production of the arylamine dendrimer-like compound of the present invention is usually preferably carried out in the presence of an inert solvent. The solvent used is not particularly limited as long as it does not significantly inhibit this reaction. For example, aromatic hydrocarbon solvents such as benzene, toluene and xylene, ethers such as diethyl ether, tetrahydrofuran and dioxane. A solvent, acetonitrile, dimethylformamide, dimethyl sulfoxide, hexamethylphosphotriamide, etc. can be mentioned. Of these, aromatic hydrocarbon solvents such as benzene, toluene and xylene are preferred.

  The production of the arylamine dendrimer-like compound of the present invention is preferably carried out under normal pressure and in an inert gas atmosphere such as nitrogen or argon, but can be carried out even under pressurized conditions.

  In the method of the present invention, the reaction temperature is not particularly limited as long as it is a reaction temperature capable of producing an arylamine dendrimer-like compound, but is usually 20 to 300 ° C, preferably 50 to 200 ° C, more preferably It is the range of 100-150 degreeC.

  In the method of the present invention, the reaction time is not particularly limited because it is not constant depending on the arylamine dendrimer-like compound to be produced, but in many cases, it may be selected from the range of several minutes to 72 hours. Preferably it is less than 24 hours.

  The arylamine dendrimer-like compound in the present invention can be purified by reprecipitation. It is also possible to perform adsorption treatment with silica gel, activated alumina or the like for removing impurities.

  Although the weight average molecular weight of the arylamine dendrimer-like compound of the present invention is not particularly limited, it is in the range of 1,000 to 1,000,000 in terms of polystyrene, and more preferably in the range of 10,000 to 1,000 in terms of polystyrene. It is in the range of 500,000.

  The arylamine dendrimer-like compound of the present invention is used as a conductive polymer material in electronic devices such as field effect transistors, optical functional devices, dye-sensitized solar cells, and organic electroluminescence devices. In particular, it is extremely useful as a hole transport material, a light emitting material, and a buffer material of an organic electroluminescence device.

  If the organic EL element of this invention is equipped with the organic layer containing the said polymeric material, an element structure will not be specifically limited. Since the arylamine dendrimer-like compound of the present invention is excellent in solubility, for example, a spin coating method, a casting method, a dipping method, a bar coating method, a roll using a solution, a mixed solution or a melt of these materials is used. The element can be easily produced by a conventionally known coating method such as a coating method. It can also be easily produced by an ink jet method, a Langmuir-Blodgett method, or the like.

  The present invention provides a novel arylamine dendrimer-like compound having superior durability and luminous efficiency over conventional materials, an efficient production method thereof, and an application thereof.

  The novel arylamine dendrimer-like compound of the present invention is excellent in solubility and also in light emission efficiency and current efficiency in the case of an organic EL device. Furthermore, it has very good film formability and stability. It is extremely useful as a conductive polymer for use in electronic devices such as field effect transistors, optical functional devices, and dye-sensitized solar cells as well as hole transport materials, light emitting materials, and buffer materials for organic EL devices. The present invention is very significant industrially.

The measurement result of the infrared spectroscopy analysis of the triarylamine polymer represented by General formula (15) is shown.

  Examples of the present invention are shown below, but the present invention is not limited to these Examples.

Reaction example 1
To a 100 ml four-necked round bottom flask equipped with a condenser and a thermometer, at room temperature, 17.05 g (42 mmol) of 4,4′-diiodobiphenyl, 5.97 g (40 mmol) of 4-n-butylaniline, sodium- There were charged 9.23 g (96 mmol; 2.4 equivalents relative to the primary amino group) of tert-butoxide and 200 ml of o-xylene. To this mixed solution, 180 mg (0.20 mmol; 0.50 mol% with respect to the primary amino group) of tris (dibenzylideneacetone) dipalladium prepared in advance in a nitrogen atmosphere and 0.33 g of tri-tert-butylphosphine (1. 60 mmol; 4 equivalents of atoms per palladium atom) in o-xylene (10 ml) was added. Thereafter, the temperature was raised to 120 ° C. in a nitrogen atmosphere, and the mixture was aged for 3 hours while heating and stirring at 120 ° C.

  After 3 hours, the reaction mixture was cooled to about 80 ° C. and then slowly added to a stirred solution of 90% aqueous acetone (1000 ml). The solid was collected by filtration and washed in the order of acetone, water, and acetone, and then dried under reduced pressure to obtain a pale yellow powder (yield 90%).

  When the obtained powder was measured by elemental analysis and infrared spectroscopic analysis, it was confirmed to be a triarylamine polymer represented by the following general formula (15). The measurement result of infrared spectroscopy is shown in FIG. The obtained polymer was analyzed by THF-based GPC (manufactured by Tosoh: HLC-8220; column: TSKgelSuperH3000-TSKgelSuperH2000-TSKgelSuperH1000 (both manufactured by Tosoh)). The molecular weight was 9,000 (dispersion degree 3.1).

Example 1
In a 300 ml four-necked round bottom flask equipped with a condenser and a thermometer, 4.00 g of arylamine polymer represented by the general formula (15) synthesized in Reaction Example 1 at room temperature (in terms of number average molecular weight: 0.44 mmol) ), 0.24 g (2.22 mmol) of sodium-tert-butoxide, 12.0 mg (0.11 mmol) of p-phenylenediamine and 136 ml of o-xylene. To this mixed solution, 11.0 mg (0.012 mmol) of tris (dibenzylideneacetone) dipalladium prepared in advance in a nitrogen atmosphere and 20 mg of tri-tert-butylphosphine (0.10 mmol; 4 equivalents with respect to palladium atom) Of o-xylene (5 ml) was added. Thereafter, the temperature was raised to 120 ° C. in a nitrogen atmosphere, and the mixture was aged for 3 hours while heating and stirring at 120 ° C.

  A solution of 75.1 mg (0.44 mmol) of diphenylamine in o-xylene (2 ml) was added and aged at 120 ° C. for another 3 hours. Next, a solution of 83.7 mg (0.53 mmol) of bromobenzene in o-xylene (2 ml) was added, and the mixture was further aged at 120 ° C. for 3 hours.

  After completion of the reaction, the reaction mixture was cooled to about 80 ° C. and then slowly added to a stirred solution of 90% aqueous acetone (1000 ml). The solid was collected by filtration, washed in the order of acetone, water, and acetone, and then dried under reduced pressure to obtain a pale yellow powder (yield 84%). The obtained arylamine dendrimer-like compound was analyzed by THF-based GPC (manufactured by Tosoh: HLC-8220), and as a result, it had a weight average molecular weight of 145,300 and a number average molecular weight of 19,000 in terms of polystyrene. The measurement results of elemental analysis are shown in Table 2.

Example 2
The reaction was performed in the same manner as in Example 1 except that p-phenylenediamine was changed to 21.8 mg (0.11 mmol) of 2,7-diaminofluorene.

  The obtained arylamine dendrimer-like compound was analyzed by THF-based GPC (manufactured by Tosoh: HLC-8220), and as a result, the weight average molecular weight was 122,000 and the number average molecular weight was 17,800 in terms of polystyrene. Table 3 shows the measurement results of elemental analysis.

Example 3
The reaction was performed in the same manner as in Example 1 except that p-phenylenediamine was changed to 38.9 mg (0.11 mmol) of 9,9-bis (4-aminophenyl) fluorene.

  The obtained arylamine dendrimer-like compound was analyzed by THF-based GPC (manufactured by Tosoh: HLC-8220). As a result, the weight average molecular weight was 134,100 and the number average molecular weight was 18,000 in terms of polystyrene. Table 4 shows the measurement results of elemental analysis.

Example 4 (Production and Evaluation of Device)
A glass substrate having an ITO transparent electrode having a thickness of 130 nm was ultrasonically washed successively with acetone and isopropyl alcohol, then boiled and washed with isopropyl alcohol, and then dried. Furthermore, what was UV / ozone treated was used as a transparent conductive support substrate.

On this ITO glass substrate, the arylamine dendrimer-like compound synthesized in Example 1 was formed into a film with a thickness of 30 nm by spin coating using the 1.0 wt% chlorobenzene solution. After drying at 160 ° C. for 3 hours, 4,4 ′, 4 ″ -tris (2-naphthylphenylamino) triphenylamine (2-TNATA, 30 nm) was added on top of 4,4′-bis [N -(1-Naphtyl) -N-phenylamino] biphenyl (α-NPB, 50 nm) and aluminum 8-quinolinol complex (Alq ₃ , 50 nm) were deposited in this order. The organic compound was deposited under the same conditions of a vacuum degree of 1.0 × 10 ⁻⁴ Pa and a deposition rate of 0.3 nm / second.

  Next, lithium fluoride (0.8 nm) and aluminum (150 nm) were deposited in this order to form a metal electrode.

  Further, a protective glass substrate was stacked in a nitrogen atmosphere, and the organic EL sealing agent was heat-cured at 80 ° C. for 3 hours, adhered and sealed.

  Table 5 shows the light emission characteristics when a voltage is applied to the EL element manufactured as described above using the ITO electrode as the positive electrode and the LiF-Al electrode as the negative electrode.

Example 5 (Production and Evaluation of Device)
A device was prepared in the same manner as in Example 4 except that the arylamine dendrimer compound synthesized in Example 2 was used instead of the arylamine dendrimer compound synthesized in Example 1. The emission characteristics are shown in Table 5.

Example 6 (Production and Evaluation of Device)
In Example 4, a device was prepared in the same manner as in Example 4 except that the arylamine dendrimer compound synthesized in Example 3 was used instead of the arylamine dendrimer compound synthesized in Example 1. The emission characteristics are shown in Table 5.

  From the above results, the EL device using the arylamine dendrimer-like compound of the present invention can be driven at a low voltage, has improved luminous efficiency and current efficiency, and requires less power consumption.

Claims (8)

The following general formula (1)

(In the formula, Ar ¹ and Ar ² each independently represent an aromatic group having 6 to 60 carbon atoms which may have a substituent, and n represents an integer of 2 or more.)
And an arylamine polymer skeleton represented by the general formula (2)

(In the formula, Ar ³ represents an arylene group having 6 to 30 carbon atoms or a heteroarylene group having 3 to 30 carbon atoms, and R represents a binding site of the arylamine polymer skeleton represented by the general formula (1). )
An arylamine dendrimer-like compound having a structure in which an aromatic diamine optionally having at least one substituent represented by The arylamine dendrimer-like compound according to claim 1, wherein in the general formula (1), Ar ¹ is any one of the following general formulas (3) to (6).

(In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group having 1 to 18 carbon atoms or an optionally substituted phenyl group, and m is an integer of 1 to 3) Represents.) The arylamine dendrimer-like compound according to claim 1 or 2, wherein in the general formula (1), Ar ² is any one of the following general formulas (7) to (12).

(In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ each independently have an alkyl group having 1 to 18 carbon atoms, or a substituent. A represents an integer of 0 to 5). Ar ^{3 in the} general formula (2) may have a phenylene group, biphenylene group, terphenylene group, thienylene group, pyrrolylene group, naphthylene group, anthracenylene group, phenanthrylene group, fluorenylene group, pyrenylene group, or The arylamine dendrimer-like compound according to any one of claims 1 to 3, which is any one of N-substituted carbazolylene groups. The arylamine dendrimer-like compound according to any one of claims 1 to 4, wherein the weight average molecular weight is in a range of 1,000 to 1,000,000 in terms of polystyrene. The following general formula (13)

(In the formula, Ar ¹ and Ar ² are each independently an aromatic group having 6 to 60 carbon atoms which may have a substituent, X represents a halogen atom, and n represents an integer of 2 or more.)
And an arylamine polymer represented by the general formula (14)

(In the formula, Ar ³ represents an arylene group having 6 to 30 carbon atoms or a heteroarylene group having 3 to 30 carbon atoms.)
The arylamine dendrimer-like compound according to claim 1, which is reacted with an aromatic diamine which may have at least one substituent represented by formula (I) in the presence of a palladium catalyst and a base. Method. An electronic device using the arylamine dendrimer-like compound according to claim 1. The electronic device according to claim 7, wherein the electronic device is an organic electroluminescence device.

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