JP4762514B2 - 3,6-diphenylcarbazole derivative - Google Patents

Description

  The present invention relates to a novel 3,6-diphenylcarbazole, and particularly to a useful carbazole derivative capable of realizing an organic EL device having high durability and high light emission efficiency. The present invention also relates to a novel 3,6-diphenylcarbazole useful as a charge transport material for an organic photoreceptor, particularly as a photoelectric conversion element which is another application field.

  Organic thin-film EL devices have been attracting attention from the viewpoints of being self-luminous and having high viewing angle dependency, high visibility, and being thin-film type completely solid devices that can save space. Practical research is being developed. However, at present, there are many problems to be solved such as further improvement of energy conversion efficiency and light emission quantum efficiency, and improvement of stability of organic thin film over time (improvement of device durability).

  So far, organic thin film EL elements have been reported to use low molecules and those using polymers. For low molecular weight materials, it has been reported that high efficiency can be realized by employing various laminated structures, and that durability can be improved by well controlling the doping method. However, in the case of a low molecular assembly, it has been reported that the film state changes with time for a long time, and has an essential problem regarding the stability of the film.

  On the other hand, with regard to polymer materials, until now, vigorous studies have been made mainly on poly-p-phenylene vinylene (PPV) series, poly-thiophene, and the like. However, it is difficult to increase the purity of these material systems, and the fluorescence quantum yield is essentially low, so that a high-performance EL element has not been obtained at present. In the case of a polymer material, when considering that the glass state is essentially stable, an excellent EL element can be constructed if high fluorescence quantum efficiency can be imparted. Thus, it is known that there are advantages and disadvantages in the use of low molecules and the use of polymers.

  In recent years, studies on high efficiency using triplet excitons have been made vigorously (Non-patent Document 1, etc.), and it has been clarified that luminous efficiency is greatly improved. Along with this, reports of host materials used for the light emitting layer are increasing. Among these, a representative host material is 4,4′-bis (carbazolyl-9) biphenyl (CBP) represented by the following formula, and CBP crystallization progresses in the light emitting layer by subsequent studies. However, it has become clear that this shortens the lifetime of the element (see, for example, Patent Document 1).

  In order to avoid this problem, carbazole compounds that replace CBP have been studied (see, for example, Patent Document 1 and Patent Document 2). Further, studies have been made on a synthesis method of a carbazole compound or an electrochemical behavior of the carbazole compound (see, for example, Non-Patent Document 2 and Non-Patent Document 3). However, none of the described compounds has sufficient durability and luminous efficiency as a device.

WO01 / 72927 A1 JP-A-9-310066 T.A. Tsutsui et al. / Jpn. J. et al. Appl. Phys. Vol. 38 L1502 (1999) M.M. Park et al. / Tetrahedron 54 (1998) 12707-12714 W. Laum et al. / Journal future Praktische Chemie (Leipzig) 317 (6) (1975) 995-1004

  The present invention has been made in view of the current state of the prior art, and an object of the present invention is to provide a novel carbazole derivative that realizes an organic EL element having particularly high durability and high light emission efficiency as a material for an organic EL element. And

The present invention achieves the above object and has the following features.
The invention according to claim 1, obtained by reaction with 3,6-diphenyl carbazole derivative and alkylation agent represented by the following general formula (I), 3 represented by the following formula (II), Characterized by 6-diphenylcarbazole derivatives.

（式中、Ｒ_１およびＲ_２はメトキシ基を表し、Ｒ_３およびＲ_４は水素原子を表し、Ｒ_５はエチル基を表す。）
また、請求項２に記載の発明は、下記一般式（Ｉ）で表される３，６−ジフェニルカルバゾール誘導体とアリール化剤との反応により得られ、下記一般式（ＩＩＩ）で表される３，６−ジフェニルカルバゾール誘導体を特徴とする。

(In the formula, R ₁ and R ₂ represent a methoxy group , R ₃ and R ₄ represent a hydrogen atom, and R ₅ represents an ethyl group .)
The invention according to claim 2 is obtained by reacting a 3,6-diphenylcarbazole derivative represented by the following general formula (I) with an arylating agent, and represented by the following general formula (III). , 6-Diphenylcarbazole derivative.

（式中、Ｒ_１、Ｒ_２はメトキシ基、又はメチル基を表し、Ｒ_３およびＲ_４は水素原子を表し、Ｒ_６は、水素原子、メチル基、メトキシ基、またはフェニル基、を表す。）
また、請求項３に記載の発明は、下記一般式（Ｉ）で表される３，６−ジフェニルカルバゾール誘導体とアリール化剤との反応により得られ、下記一般式（ＩＩＩ）で表される３，６−ジフェニルカルバゾール誘導体を特徴とする。

(In the formula, R ₁ and R ₂ represent a methoxy group or a methyl group , R ₃ and R ₄ represent a hydrogen atom, and R ₆ represents a hydrogen atom, a methyl group, a methoxy group, or a phenyl group . )
The invention according to claim 3 is obtained by reaction of a 3,6-diphenylcarbazole derivative represented by the following general formula (I) with an arylating agent, and represented by the following general formula (III). , 6-Diphenylcarbazole derivative.

（式中、Ｒ_１、Ｒ_２は、ハロゲン原子を表し、Ｒ_３Ｒ_４及びＲ_６は水素原子を表す）
また、請求項４に記載の発明は、前記請求項１乃至３のいずれかに記載の３，６−ジフェニルカルバゾール誘導体を含む有機EL素子を特徴とする。

(Wherein R ₁ and R ₂ represent a halogen atom , and R ₃ R ₄ and R ₆ represent a hydrogen atom )
According to a fourth aspect of the present invention, there is provided an organic EL device including the 3,6-diphenylcarbazole derivative according to any one of the first to third aspects.

When the novel 3,6-diphenylcarbazole derivative of the present invention is used as an organic EL device, durability is high and high light emission efficiency can be obtained.
The novel 3,6-diphenylcarbazole derivative of the present invention is useful as an organic photoreceptor charge transport material as a photoelectric conversion element.

The present invention is described in further detail below.
The 3,6-diphenyl-9H-carbazole derivative represented by the general formula (I) and the 3,6-diphenylcarbazole derivative represented by the general formula (II) of the present invention can be produced by the following route (reaction process).

  The first stage 3,6-diaryl-9H-carbazole derivative is obtained by a Suzuki-Miyaura reaction known as a cross-coupling reaction between an aryl boron compound and an organic halide using a palladium catalyst.

  Instead of the aryl boronic acid described above, an aryl boronic acid ester synthesized from an aryl halide using bis (pinacolato) diboron which is thermally stable and can be easily handled in air may be used.

  The halogen atom in the 3,6-dihalogeno-9H-carbazole derivative is preferably iodine or bromine from the viewpoint of reactivity.

Various catalysts such as Pd (PPh ₃ ) ₄ , PdCl ₂ (PPh ₃ ) ₂ , Pd (OAc) _2, and PdCl ₂ can be used as the palladium catalyst, but most commonly used is Pd (PPh ₃ ) _4. Used.

This reaction always requires a base, but relatively weak bases such as Na ₂ CO ₃ , NaHCO ₃ give good results. When affected by steric hindrance or the like, strong bases such as Ba (OH) ₂ and K ₃ PO ₄ are effective. Other caustic soda, caustic potash, metal alcosides such as potassium t-butoxide, sodium t-butoxide, lithium t-butoxide, potassium 2-methyl-2-butoxide, sodium 2-methyl-2-butoxide, sodium methoxide, sodium ethoxide, Potassium ethoxide, potassium methoxide, and the like can also be used. An organic base such as triethylamine can also be used.

  Examples of the reaction solvent include alcohols such as methanol, ethanol, isopropanol, butanol, 2-methoxyethanol, 1,2-dimethoxyethane, and bis (2-methoxyethyl) ether, and ether ethers, and cyclic ethers such as dioxane and tetrahydrofuran. Benzene, toluene, xylene, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like.

The 3,6-diaryl-9H-carbazole derivative obtained in the first step is then derivatized into the 3,6-diphenylcarbazole derivative of the present invention by, for example, an aryl halide as an arylating agent and the Ullmann reaction in the second step. Is done.
In the second stage reaction, examples of the alkylating agent used for alkylation include diethyl sulfate.

  The 3,6-diphenyl-9H-carbazole derivative represented by the general formula (I) of the present invention thus obtained and the 3,6 diphenyl-9H-carbazole derivative represented by the general formula (II), (III) or (IV). Specific examples of each substituent of the 6-diphenylcarbazole derivative are shown below.

When R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are substituted or unsubstituted alkyl groups in the general formula (I) and the general formulas (II), (III) and (IV) The following can be mentioned.

  A linear, branched or cyclic alkyl group having 1 to 25 carbon atoms, and these alkyl groups are further substituted with a fluorine atom, a cyano group, a phenyl group, a halogen atom or a linear or branched alkyl group It may contain a phenyl group. Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, t-butyl group, s-butyl group, n-butyl group, i-butyl group, pentyl group, hexyl group, heptyl group, Octyl group, nonyl group, decyl group, 3,7-dimethyloctyl group, 2-ethylhexyl group, trifluoromethyl group, 2-cyanoethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, cyclopentyl group, A cyclohexyl group etc. are mentioned.

When R ₁ , R ₂ and R ₆ are substituted or unsubstituted alkoxy groups, specific examples include those in which an oxygen atom is inserted into the bonding position of the substituted or unsubstituted alkyl group to form an alkoxy group.

When R ₁ , R ₂ and R ₆ are halogen atoms, mention may be made of fluorine atoms, chlorine atoms and bromine atoms.

An aryl group in which R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ may have a substituent in the general formula (I) and the general formulas (II), (III) and (IV) The following can be mentioned.

  Phenyl group, naphthyl group, biphenyl group, terphenyl group, pyrenyl group, fluorenyl group, 9,9-dimethyl-2-fluorenyl group, azulenyl group, anthryl group, triphenylenyl group, chrysenyl group, fluorenylidenephenyl group, 5H- Examples include dibenzo [a, d] cycloheptenylidenephenyl group, furyl group, benzofuranyl group, carbazolyl group, pyridyl group, pyrrolidyl group, oxazolyl group and the like. These include the above-mentioned substituted or unsubstituted alkyl group, alkoxy group, And a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom as a substituent.

Here, in the 3,6-diphenylcarbazole derivative of the present invention, in the general formula (I), when R ₁ and R ₂ are aryl groups which may have a substituent, at least one of the aryl groups is linked. A carbocyclic aromatic group which may have a group is preferable, and a carbocyclic aromatic group in which both of the aryl groups may have a linking group is more preferable. Further, the carbocyclic aromatic group is preferably one having no linking group.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples unless it exceeds the gist.

[ Reference Example 1]
Take 20.0 g of 3,6-dibromocarbazole, 20.6 g of 4-methoxyphenylboronic acid and 2.23 g of tetrakis (triphenylphosphine) palladium in 60 ml of ethanol and 250 ml of toluene, and add 120 ml of 22% aqueous solution of sodium carbonate to this. The mixture was heated to reflux under a nitrogen atmosphere for 5.5 hours. After removing insoluble matter using a filter aid during heating, the organic layer was separated and the solvent was distilled off under reduced pressure. After washing with water and drying, 20.2 g of a light brown powder was obtained. This was recrystallized from a mixed solvent of toluene / ethanol to obtain 13.5 g of colorless needle-like 3,6-bis (4-methoxyphenyl) carbazole.
Melting point 213.0-214.0 ° C
Elemental analysis value (%) Measured value / calculated value C: 82.69 / 82.30 H: 5.61 / 5.58 N: 3.70 / 3.69
The infrared absorption spectrum (KBr tablet method) is shown in FIG.
NH stretching vibration 3426 cm ⁻¹ COC stretching vibration 1235 cm ⁻¹ , 1035 cm ⁻¹

[Example 1 ]
13.4 g of 3,6-bis (4-methoxyphenyl) carbazole, 40 ml of iodobenzene, 19.3 g of potassium carbonate and 1.0 g of copper powder were heated to reflux for 3 hours under a nitrogen atmosphere. After cooling to 100 ° C., toluene was added, and insoluble matters were removed using a filter aid. The solvent was distilled off under reduced pressure, followed by washing with methanol to obtain 14.8 g of colorless needle-like 3,6-bis (4-methoxyphenyl) -9-phenylcarbazole. Melting point: 169.5-170.5 ° C. This was recrystallized from a mixed solvent of toluene / ethanol to obtain colorless needle crystals.
Melting point 170.0-171.0 ° C
Elemental analysis value (%) Measured value / calculated value C: 84.31 / 84.37 H: 5.44 / 5.53 N: 3.06 / 3.07
The infrared absorption spectrum (KBr tablet method) is shown in FIG.

[Example 2 ] to [Example 6 ]
The 3,6-diphenylcarbazole derivative of the present invention shown in Table 1 was obtained in the same manner as in Example 1 except that the corresponding iodo compound shown in Table 1 was used instead of iodobenzene in Example 1 . The results are shown in Table 1 together with the analysis results.

[ Reference Example 2 ]
Take 12.7 g of 3,6-dibromocarbazole, 10.0 g of phenylboronic acid, 2.61 g of tetrakis (triphenylphosphine) palladium in 40 ml of ethanol and 170 ml of toluene, add 90 ml of 22% aqueous solution of sodium carbonate to this, and add nitrogen atmosphere. The mixture was heated to reflux for 5 hours. After removing insoluble matter using a filter aid during heating, the organic layer was separated and the solvent was distilled off under reduced pressure. After washing with water and drying, a light brown powder was obtained. This was subjected to column chromatography (eluent: toluene) and then washed with hexane to obtain 6.0 g of colorless needle-like 3,6-diphenylcarbazole.
Melting point: 180.5-181.5 ° C
Elemental analysis value (%) Measured value / calculated value C: 90.44 / 90.24 H: 5.25 / 5.38 N: 4.31 / 4.39
Infrared absorption spectrum (KBr tablet method)
NH stretching vibration 3423 cm ⁻¹ , 3378 cm ⁻¹

[ Reference Example 3 ] to [ Reference Example 7 ]
Yield the corresponding other using arylboronic acids to Reference Example 2 in the same manner as in operation to illustrated in Table 2 3,6-diphenyl -9H- carbazole derivative shown in Table 2 in place of phenylboronic acid used in Reference Example 2 It was.

[ Reference Example 8 ], [Example 7 ] to [Example 11 ]
The 3,6-diphenyl-9H-carbazole derivative obtained in Reference Examples 2 to 7 and iodobenzene were used in the same manner as in Example 1 to obtain the 3,6-diphenylcarbazole derivative of the present invention shown in Table 3. Obtained.

[ Reference Example 9 ]
1.62 g of 3,6-bis (4-biphenylyl) carbazole obtained in Reference Example 7 , 1.43 g of 4-iodobiphenyl, 1.90 g of potassium carbonate, and 0.20 g of copper powder were added in 20 ml of nitrobenzene under nitrogen atmosphere. Heated to reflux for hours. After cooling to 100 ° C., insoluble matters were removed using a filter aid. The solvent was distilled off under reduced pressure, washed with methanol, and recrystallized from a mixed solvent of toluene / ethanol to obtain 0.90 g of colorless needle crystal 3,6,9-tris (4-biphenylyl) carbazole.
Melting point 273.5-275.0 ° C
Elemental analysis value (%) Measured value / calculated value C: 92.72 / 92.42 H: 5.10 / 5.33 N: 2.22 / 2.25

[ Reference Example 10 ]
2.0 g of 3,6-diphenylcarbazole obtained in Reference Example 2 and 0.26 g of sodium hydroxide were taken up in 200 ml of dehydrated acetone, and 0.89 ml of diethyl sulfuric acid was added dropwise at room temperature over 30 minutes. After stirring at room temperature for 1 day, the contents were poured into water and extracted with ethyl acetate. The organic layer was washed with an aqueous sodium hydrogen carbonate solution, then washed with water and dried, and the solvent was distilled off to obtain a colorless powder. Recrystallization from a mixed solvent of toluene / ethanol gave 1.70 g of colorless plate-like 3,6-diphenyl-9-ethylcarbazole.
Melting point: 184.5-185.0 ° C
Elemental analysis value (%) Measured value / calculated value C: 89.86 / 89.86 H: 6.03 / 6.10 N: 3.97 / 4.03

[Example 12 ]
The procedure of Example 10 was repeated except that 3,6-bis (4-methoxyphenyl) carbazole obtained in Reference Example 1 was used instead of 3,6-diphenylcarbazole used in Reference Example 10 . Plate-like 3,6-bis (4-methoxyphenyl) -9-ethylcarbazole was obtained.
Melting point 226.5-227.5 ° C
Elemental analysis value (%) Measured value / calculated value C: 82.95 / 82.53 H: 6.22 / 6.18 N: 3.48 / 3.44

[ Reference Example 11 ]
11.30 g of 3,6-dibromocarbazole, 10.40 g of 2-methylphenylboronic acid, and 1.27 g of tetrakis (triphenylphosphine) palladium were placed in 30 ml of ethanol and 125 ml of toluene, and 75 g of a 22% aqueous solution of sodium carbonate was added thereto. The mixture was heated to reflux for 4 hours under a nitrogen atmosphere. After removing insoluble matter using a filter aid during heating, the organic layer was separated and the solvent was distilled off under reduced pressure. After washing with water and drying, a light brown powder was obtained. This was subjected to silica gel column chromatography (eluent: toluene / hexane = 1/1 volume ratio) to obtain 7.44 g of colorless needle-like 3,6-bis (2-methylphenyl) carbazole.
Melting point Glassy Elemental analysis value (%) Measured value / calculated value C: 89.62 / 89.88 H: 6.00 / 6.09 N: 4.00 / 4.03
Infrared absorption spectrum (KBr tablet method)
NH stretching vibration 3411cm ^-1

[Example 13 ]
3.41 g of 3,6-bis (2-methylphenyl) carbazole, 15 ml of 2-iodotoluene, 5.51 g of potassium carbonate and 0.5 g of copper powder were heated to reflux for 3 hours under a nitrogen atmosphere. After cooling to room temperature, toluene was added and insolubles were removed using a filter aid. The solvent was distilled off under reduced pressure, followed by silica gel column chromatography (eluent: toluene / hexane = 1/8 volume ratio) to give colorless needle-like 3,6,9-tris (2-methylphenyl) carbazole 3.60 g. Got.
Melting point 80.0-82.0 ° C
Elemental analysis value (%) Measured value / calculated value C: 90.84 / 90.58 H: 6.26 / 6.22 N: 3.12 / 3.20

[Example 14 ]
In Example 13 , 3,6-bis (2-methylphenyl) -9-phenylcarbazole was obtained in the same manner as in Example 13 except that iodobenzene was used instead of 2-iodotoluene.
Melting point: 121.0-122.0 ° C
Elemental analysis value (%) Measured value / calculated value C: 90.84 / 90.74 H: 6.03 / 5.95 N: 3.19 / 3.31

[Reference Example 12 ]
Take 10.00 g of 3,6-dibromocarbazole, 9.86 g of 3-fluorophenylboronic acid and 1.08 g of tetrakis (triphenylphosphine) palladium in 30 ml of ethanol and 125 ml of toluene, and add 60 g of 21.2% aqueous solution of sodium carbonate. And heated to reflux under a nitrogen atmosphere for 5 hours. After allowing to cool to room temperature, insolubles were removed using a filter aid, the organic layer was separated, and the solvent was distilled off under reduced pressure. After washing with water and drying, a light brown powder was obtained. This was subjected to adsorption treatment using silica gel and then recrystallized from a mixed solvent of ether / hexane to obtain 4.07 g of colorless needle-like 3,6-bis (3-fluorophenyl) carbazole.
Melting point 151.5-152.5 ° C
Elemental analysis value (%) Measured value / calculated value C: 81.00 / 81.11 H: 4.26 / 4.25 N: 4.00 / 3.94
Infrared absorption spectrum (KBr tablet method)
NH stretching vibration 3392cm ^-1

[Example 15 ]
3.50 g of 3,6-bis (3-fluorophenyl) carbazole, 30 ml of iodobenzene, 5.00 g of potassium carbonate, and 0.25 g of copper powder were heated to reflux under a nitrogen atmosphere for 1.5 hours. After cooling to 100 ° C., toluene was added, and insoluble matters were removed using a filter aid. After the solvent was distilled off under reduced pressure, the residue was subjected to silica gel column chromatography (eluent: toluene) and then recrystallized from ethanol to give 3,6-bis (3-fluorophenyl) -9-phenylcarbazole as colorless needle crystals. Got.
Melting point 124.5-125.5 ° C
Elemental analysis value (%) Measured value / calculated value C: 83.26 / 83.51 H: 4.22 / 4.44 N: 3.12 / 3.25

[Example 16 ]
A light brown crude product was obtained in the same manner as in Example 1 except that 2-iodotoluene was used instead of iodobenzene in Example 1 . This was subjected to silica gel column chromatography (eluent: toluene) and recrystallized from toluene / ethanol to give colorless needle-like 3,6-bis (4-methoxyphenyl) -9- (2-methylphenyl) carbazole. Got.
Melting point: 175.5-176.5 ° C
Elemental analysis value (%) Measured value / calculated value C: 84.22 / 84.41 H: 5.84 / 5.80 N: 3.00 / 2.98

[Reference Example 13 ]
Take 6.50 g of 3,6-dibromocarbazole, 10.00 g of biphenyl 2-boronic acid, 0.72 g of tetrakis (triphenylphosphine) palladium in 20 ml of ethanol and 100 ml of toluene, and add 40 g of a 22% aqueous solution of sodium carbonate thereto. The mixture was heated to reflux for 7.5 hours under a nitrogen atmosphere. After allowing to cool, toluene and water were added, and insoluble matters were removed using a filter aid. Then, the organic layer was separated and the solvent was distilled off under reduced pressure. After washing with water and drying, a light brown powder was obtained. This was subjected to silica gel column chromatography (eluent: toluene / hexane = 2/1 volume ratio) and then washed with ethanol to obtain 5.22 g of colorless needle-like 3,6-bis (2-biphenylyl) carbazole.
Melting point 186.0-189.0 ° C
Elemental analysis value (%) Measured value / calculated value C: 91.46 / 91.69 H: 5.13 / 5.34 N: 3.05 / 2.97
Infrared absorption spectrum (KBr tablet method)
NH stretching vibration 3425cm ^-1

[ Reference Example 14 ]
3,6-bis (2-biphenylyl) carbazole (3.00 g), iodobenzene (30 ml), potassium carbonate (3.70 g) and copper powder (0.5 g) were heated to reflux for 4 hours under a nitrogen atmosphere. After cooling to room temperature, toluene was added and insolubles were removed using a filter aid. After the solvent was distilled off under reduced pressure, the precipitated crystals were washed with ethanol and recrystallized from a toluene / ethanol mixed solvent to give colorless needle-like 3,6-bis (2-biphenylyl) -9-phenylcarbazole. 60 g was obtained.
Melting point 233 ° C
Elemental analysis value (%) Measured value / calculated value C: 92.57 / 92.11 H: 5.26 / 5.34 N: 2.57 / 2.56

[Reference Example 15 ]
3,6-dibromocarbazole 5.27 g, 3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) biphenyl 11.3 g, tetrakis (triphenylphosphine) palladium 58 g was taken up in 16 ml of ethanol and 80 ml of toluene, to which 33 g of a 21.2% aqueous solution of sodium carbonate was added, and heated under reflux for 8 hours under a nitrogen atmosphere. After allowing to cool to room temperature, toluene was added and insolubles were removed using a filter aid. The organic layer was separated, washed with water and dried, and the solvent was distilled off under reduced pressure. This was subjected to silica gel column chromatography (eluent: toluene / hexane = 2/1 volume ratio) and then washed with ethanol to obtain 4.70 g of colorless needle-like 3,6-bis (3-biphenylyl) carbazole.
Melting point 262 ° C
Elemental analysis value (%) Measured value / calculated value C: 91.94 / 91.69 H: 5.15 / 5.34 N: 3.01 / 2.97
Infrared absorption spectrum (KBr tablet method)
NH stretching vibration 3394cm ^-1

[ Reference Example 16 ]
3.20 g of 3,6-bis (3-biphenylyl) carbazole, 40 ml of iodobenzene, 5.20 g of potassium carbonate and 0.70 g of copper powder were heated to reflux for 3 hours under a nitrogen atmosphere. After allowing to cool, toluene was added, and insoluble matters were removed using a filter aid. After the solvent was distilled off under reduced pressure, the precipitated crystals were washed with ethanol. Then, recrystallization from a mixed solvent of toluene / hexane gave 3.65 g of colorless plate-like 3,6-bis (3-biphenylyl) -9-phenylcarbazole.
Melting point 188.0-189.0 ° C
Elemental analysis value (%) Measured value / calculated value C: 92.55 / 92.11 H: 5.21 / 5.34 N: 2.59 / 2.56

[Application example]
The ITO substrate having a film thickness of 110 nm was sufficiently washed with a neutral detergent, acetone and isopropanol, boiled and washed with isopropanol, then treated in a UV-ozone chamber for 12 minutes, and placed in a vacuum deposition apparatus. 50 nm of N, N′-di-m-tolyl-N, N′-diphenyl-4,4′-diphenyldiamine (TPD) was formed as a hole transport layer under a vacuum of 1 × 10 ⁻⁴ Pa. Next, the carbazole derivative (CBZ) obtained in Example 1 and tris (2-phenylpyridine) indium [Ir (ppy) ₃ ] were formed as a light-emitting layer to a thickness of 20 nm by a co-evaporation method. At this time, the concentration of tris (2-phenylpyridine) indium was maintained at 6 wt%. Furthermore, 10 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 30 nm of 8-hydroxyquinolinol aluminum complex (Alq ₃ ) were deposited as an electron transport layer. Finally, MgAg / Ag was deposited as a cathode with a film thickness of 100/10 nm through a shadow mask to complete the device.
The device showed a current-quantum efficiency relationship as shown in FIG. 3, and showed a maximum quantum efficiency of 6.6%.
Moreover, as shown in FIG. 4, it showed a favorable current-voltage characteristic, and a maximum current density of 4.065 A / cm ² and a maximum light emission luminance of 122264 cd / m ² (FIG. 5) were observed at an applied voltage of 14.4 V. . In addition, light emission from tris (2-phenylpyridine) indium centered at 510 nm was observed in the emission spectrum.

2 is an infrared absorption spectrum (KBr tablet method) diagram of 3,6-bis (4-methoxyphenyl) carbazole obtained in Reference Example 1. FIG. 2 is an infrared absorption spectrum (KBr tablet method) diagram of 3,6-bis (4-methoxyphenyl) -9-phenylcarbazole obtained in Example 1. FIG. It is a graph which shows the relationship with the electric current 1 quantum efficiency of the organic electroluminescent element of an application example. It is a graph which shows the relationship with the current 1 voltage of the organic electroluminescent element of an application example. It is a graph which shows the relationship of the light emission luminance of an organic electroluminescent element of an application example, and an electric current.

Claims (4)

Obtained by reaction with 3,6-diphenyl carbazole derivative and alkylation agent represented by the following general formula (I), 3,6-diphenyl carbazole, characterized by being represented by the following general formula (II) Derivative.

(In the formula, R ₁ and R ₂ represent a methoxy group , R ₃ and R ₄ represent a hydrogen atom, and R ₅ represents an ethyl group .) 3,6-diphenylcarbazole derivative obtained by reaction of a 3,6-diphenylcarbazole derivative represented by the following general formula (I) and an arylating agent and represented by the following general formula (III) .

(In the formula, R ₁ and R ₂ represent a methoxy group or a methyl group , R ₃ and R ₄ represent a hydrogen atom, and R ₆ represents a hydrogen atom, a methyl group, a methoxy group, or a phenyl group . ) 3,6-diphenylcarbazole derivative obtained by reaction of a 3,6-diphenylcarbazole derivative represented by the following general formula (I) and an arylating agent and represented by the following general formula (III) .

(Wherein R ₁ and R ₂ represent a halogen atom , and R ₃ R ₄ and R ₆ represent a hydrogen atom ) An organic EL device comprising the 3,6-diphenylcarbazole derivative according to any one of claims 1 to 3.

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