KR20040092317A - Novel amine compound for organic electroluminescence material and manufacturing method thereof - Google Patents

Abstract

PURPOSE: Provided is an amine compound, which has excellent heat resistance and light-emitting luminance and efficiency suitable to be used as an organic electroluminescence material, has high solubility in organic solvents, and is prepared with ease. CONSTITUTION: The amine compound useful as an organic electroluminescence material is represented by the following formula 1. The amine compound of formula 1 is prepared by the method comprising a one-step coupling reaction in which 9-halophenanthrene represented by the following formula 3 as a starting material is reacted with N,N'-diphenylbenzidine, a palladium catalyst, a phosphine catalyst and a base. In formula 3, X represents a halogen atom.

Description

Novel amine compound for organic electroluminescence material and manufacturing method

The present invention relates to a novel amine compound of the formula (1) useful as an organic electroluminescent material and a method for producing the same.

More specifically, the present invention relates to a hole transport material for electroluminescence by forming electrons and excitons by transporting holes injected from the hole injection layer more effectively when voltage is applied in the organic electroluminescent device. The present invention relates to an amine compound useful as a constituent material of an organic EL device exhibiting excellent effects in hole transporting capacity, luminous efficiency, and glass transition temperature, and a method for producing the same.

Conventionally, the hole transport material is an amine derivative having a condensed aromatic ring as disclosed in U.S. Patent No. 5,061,569, wherein N, N'-di (naphthyl-1-yl) -N, N'-di Phenyl-4,4'-benzidine (hereinafter abbreviated α-NPD) has been used. However, α-NPD has a glass transition temperature (Tg) of 95 ° C., which is lower than 100 ° C., which is known to be poor in thermal stability. When the organic EL device using a material having a low glass transition temperature (Tg) is stored or used at a high temperature, there is a disadvantage that the so-called heat resistance, which shortens the life, is insufficient. Therefore, the importance of the material having a glass transition temperature of at least 130 ℃ in consideration of thermal stability has emerged in the industry.

In addition, the organic EL device using the α-NPD is insufficient in light emission luminance and efficiency due to performance other than heat resistance.

The present invention is the result of the present inventors earnest research to solve the above problems of the prior art, can be used as an organic electroluminescent material excellent in heat resistance, luminescence brightness and luminous efficiency, excellent solubility in organic solvents and manufacturing It is an object of the present invention to provide a novel amine compound and a method for preparing the same.

The present invention provides 4,4'-bis [N- (9-phenanthryl) -N-phenylamino] biphenyl {4,4'-bis [N-, which is an amine compound represented by Chemical Formula 1, which can be used as a hole transport material. (9-phenanthryl) -N-phenylamino] biphenyl; 9-PPB; and a method for preparing the same, various methods can be used without particular limitation, for example, 9-halophenanthrene and N, N'-di. The phenylbenzidine can be synthesized by the Ullmann reaction in which the reaction is carried out under a Cu catalyst. However, the method does not complete the reaction after 36 hours, and the yield is lower than 40%. Since the present inventors have disadvantages such as to be carried out, the present inventors have made a amine compound of the present invention by the following new method after a long study to improve it.

(The first method)

The amine of Chemical Formula 1 is composed of a one-step coupling reaction of reacting N, N'-diphenylbenzidine, palladium catalyst, phosphine catalyst and base with 9-halophenanthrene of Chemical Formula 3 as a starting material. The compound was prepared.

(Wherein X represents a halogen element)

In the amount of the reagents used in the reaction, 9-halofeneanthrene of Chemical Formula 3 uses 2 to 3 equivalents based on 1 equivalent of N, N'-diphenylbenzidine, wherein an amount smaller than 2 equivalents is used. In this case, since N, N'-diphenylbenzidine compound remains unreacted, there is a difficulty in purification, and when it is used more than 3 equivalents, there is a problem that 9-halophenanthrene compound is used in excess to remain as an unreacted substance. Since palladium catalyst and tri (t-butyl) phosphine are used as catalysts, the reaction rate is slower when using too small amount and the reaction rate is faster when high amount is used. Has its drawbacks. Thus, the palladium catalyst is 0.0001 equivalent to 0.005 equivalents to 1 equivalent of N, N'-diphenylbenzidine, and the tri (t-butyl) phosphine is 0.001 equivalent to 0.01 equivalent to 1 equivalent of N, N'-diphenylbenzidine It is the most efficient to use. Since o-xylene is used as a solvent, a volume of 1 to 10 times the use weight of the N, N'-diphenylbenzidine compound is used although there is a slight difference depending on the solubility of the reactants. In addition, the amount of sodium t-butoxide is not particularly limited, but in order to remove the amine proton of N, N'-diphenylbenzidine, two amine protons of N, N'-diphenylbenzidine are present in each molecule. It is preferable to use at least 2 equivalents or more based on the amount of, N'-diphenylbenzidine used.

Scheme 1 below uses N-N'-diphenylbenzidine, palladium acetate, tri (t-butyl) phosphine, sodium t- as a starting material using 9-halophenanthrene of Formula 3 as one embodiment of the method. The amine compound of Formula 1 was synthesized by reacting with butoxide and o-xylene.

(Wherein X represents a halogen element)

(The second method)

An amine compound of Chemical Formula 1 was prepared by reacting N- (9-phenanthryl) -N-phenylamine of Chemical Formula 4 with dihalobiphenyl, a palladium catalyst, a phosphine catalyst, and a base.

N- (9-phenanthryl) -N-phenylamine of Chemical Formula 4 was prepared by reacting 9-halophenanthrene of Chemical Formula 3 with aniline, a palladium catalyst, a phosphine catalyst, and a base, but is not particularly limited thereto. It is not.

At this time, the amount of the reagent used in the reaction is as follows.

First, in the case of synthesizing N- (9-phenanthryl) -N-phenylamine of Chemical Formula 4, 1 to 1.5 equivalents of 1-halophenanthrene of Chemical Formula 3 used as starting materials are used. If an amount less than 1 equivalent is used, the 9-halophenanthrene compound of Formula 3 remains unreacted, and thus, it is difficult to purify. When used in an amount greater than 1.5 equivalents, the aniline compound is used in an excessive amount to remain an unreacted substance. Palladium catalyst and phosphine catalyst are used in 0.0001 to 0.05 equivalents based on 1 equivalent of 9-halofeneanthrene, respectively. When the catalyst is used in less than 0.0001 equivalents, the reaction rate is not slowed down or the reaction does not proceed well. In the case of using a quantity, the reaction proceeds rapidly, but there is a difficulty in industrialization due to an increase in manufacturing cost. In the case of o-xylene used as a solvent, as mentioned in the first method, a volume of 1 to 10 times the use weight of the 9-halophenanthrene compound used as the starting material is used. In addition, a base such as sodium t-butoxide should be used in an amount of 1 equivalent to 1.5 equivalents to 1 equivalent of 9-halofenanthrene of Formula 3 since at least the equivalent of aniline should be used to remove the amine proton of the aniline compound used as a starting material. Use equivalents.

In the second step of synthesizing the amine compound of Formula 1 of the present invention, dihalobiphenyl has N- (9-phenanthryl) -N-phenylamine compound 1 of Formula 4, which is used as a starting material because two reaction sites exist. 0.5 equivalent should be used for the equivalent. For palladium catalyst, 0.0001 equivalent to 0.005 equivalent based on 1 equivalent of the N- (9-phenanthryl) -N-phenylamine compound represented by Formula 4, and the phosphine catalyst represented by Formula 4 0.001 equivalent to 0.01 equivalent is used for 1 equivalent of N- (9-phenanthryl) -N-phenylamine compound, and o-xylene is used as a solvent, so there is a slight difference depending on the solubility of the reactants. A volume of 1 to 10 times the use weight of the N- (9-phenanthryl) -N-phenylamine compound is used. In addition, a base such as sodium t-butoxide is used to remove N- (9-) of formula 4 to remove amine protons present in each molecule of N- (9-phenanthryl) -N-phenylamine compound of formula 4. The same amount of phenanthryl) -N-phenylamine should be used at least.

Reaction Scheme 2 is a compound of Formula 4 by reacting 9-halofeneanthrene and aniline of Formula 3 with palladium acetate, tri (t-butyl) phosphine, sodium t-butoxide, and o-xylene as one of the examples of the above method. The N- (9-phenanthryl) -N-phenylamine was synthesized and then reacted with dihalobiphenyl to synthesize the amine compound of Chemical Formula 1 of the present invention.

(Wherein X represents a halogen element)

In the present invention, the halogen element of 9-halogenanthrene and dihalobiphenyl used as starting materials in the first and second methods represents fluorine, chlorine, bromine, iodine, but fluorine, chlorine In the case of, since the reaction rate is slow or does not progress, bromine and iodine are preferable.

In addition, the palladium catalyst may be selected from the group consisting of palladium acetate, tris (dibenzylidene acetone) dipalladium can be used.

The amine compounds of Chemical Formula 1 of the present invention synthesized through the above Reaction Scheme 1 and Scheme 2 were all purified using the recrystallization and sublimation method due to the characteristics of the organic electroluminescent device requiring high purity. The amine compound of the formula (1) after the purification process has a glass transition temperature of 146 ℃ higher than 95 ℃ of α-NPD was found to be excellent thermal stability. The amine compound represented by Chemical Formula 1 of the present invention exhibited high luminance when irradiated with UV, and obtained PL results of 456 nm (Excitation: 339 nm).

Hereinafter, the present invention will be described in more detail.

The invention can be better understood by the following examples and comparative examples, which are intended to illustrate the invention and are not intended to limit the scope of protection defined by the appended claims.

<Example>

Example 1 (First Method)

1) N, N'-diphenylbenzidine (10.0 g, 28.8 mmol, 97% from Acros), 9-bromophenanthrene (15.4 g, 57.7 mmol, from Aldrich) in o-xylene (40 ml) under nitrogen atmosphere 96%), palladium acetate (3.30 mg, 0.0144 mmol, 98% from Aldrich), and sodium t-butoxide (6.86 g, 69.2 mmol, 97% from Aldrich) were added and stirred for 10 minutes before tri (t-butyl) Phosphine (118 mg, 0.0577 mmol, 99% Strem product) was added.

2) Then, the temperature of the reaction mixture was raised to 120 ° C. and the reaction was carried out for 24 hours.

3) Check the completeness of the reaction using TLC (EA / Hexane = 1/10), and when the reaction is completed, lower the temperature of the reaction mixture to 60 ° C., add acetonitrile (200 ml), stir, and filter the product. It was washed in the order of acetonitrile (500 ml), 50% aqueous methanol solution (500 ml) to give 9.70 g (49.0%) of a yellowish brown solid product.

4) The solid product was identified as 4,4'-bis [N- (9-phenanthryl) -N-phenylamino] biphenyl having the following characteristics and structural formula (1) through various tests.

* MALDI-TOF MS: 688.80 (calculated: 688.86)

* PL: 456 nm (Excitation: 339 nm)

* ^One H-NMR (500 MHz, DMSO-d ₆ ): δ = 8.92 (d, J = 8.30 Hz, 2H), 8.86 (d, J = 8.30 Hz, 2H), 7.97 (d, J = 8.30 Hz, 2H), 7.95 (d, J = 8.30 Hz, 2H), 7.77 (s, 2H), 7.70 (t, J = 7.50 Hz, 4H), 7.62 (t, J = 7.50 Hz, 2H), 7.56 (t, J = 7.50 Hz, 2H), 7.46 and 7.01 (AB, J = 8.70Hz, 8H), 7.25 (t, J = 7.50Hz, 4H), 7.05 (d, J = 7.50Hz, 4H), 6.96 (t, J = 7.50 Hz, 2H).

* m.p. : 290.1 ° C, Tg: 146.66 ° C [Measurement by DSC]

Example 2

The reaction was carried out under the same conditions except that 9-fluorophenanthrene was used instead of 9-bromophenanthrene used as a starting material in Example 1, but the reaction did not proceed.

Example 3

The reaction was carried out under the same conditions except that 9-chlorophenanthrene was used instead of 9-bromophenanthrene used as a starting material in Example 1 to obtain 5.54 g (28.0%) of a yellowish brown solid product.

Example 4

The reaction was carried out under the same conditions except that 9-iodophenanthrene was used instead of 9-bromophenanthrene used as a starting material in Example 1, to obtain 11.2 g (56.6%) of a yellowish brown solid product.

Example 5 (second method)

1) Aniline (8.40 g, 89.6 mmol, 99% from Junsei), 9-bromophenanthrene (20.0 g, 76.2 mmol, 96% from Aldrich), Tris (di) in o-xylene (50 ml) under nitrogen atmosphere Benzylideneacetone) dipalladium (1.40 g, 1.49 mmol, 98% from Aldrich), and sodium t-butoxide (11.1 g, 112 mmol, 97% from Aldrich) were added and stirred for 5 minutes before tri (t-butyl) Phosphine (3.80 g, 1.87 mmol, 99% Strem product) was added.

2) The reaction mixture was then stirred at room temperature for 1 hour and then filtered to remove solvent and aniline.

3) The filtered solid compound was washed with water, added to EA / Hexane = 1: 15 mixed solution (100 ml), stirred for 10 minutes, filtered and dried in vacuo to give 19.0 g (92.7%) of N- (9-phenane). Tril) -N-phenylamine was obtained.

4) Diiodobiphenyl (10.0 g, 22.2 mmol, 90% from Aldrich) in o-xylene (32 ml) under nitrogen atmosphere, N- (9-phenanthryl) -N-phenylamine (15.2 g) prepared above , 55.5 mmol), palladium acetate (2.55 mg, 0.0111 mmol, 98% from Aldrich), and sodium t-butoxide (5.25 g, 50.3 mmol, 97% from Aldrich) were added and stirred for 10 minutes followed by tri (t-butyl Phosphine (59.0 mg, 0.0289 mmol, 99% Strem product) was added.

5) The reaction mixture was heated up to 120 ° C. and reacted for 4 hours.

6) Check the completeness of the reaction using TLC (EA / Hexane = 1/10) and when the reaction is complete, lower the temperature of the reaction mixture to 60 ° C, add acetonitrile (200 ml) and stir and filter the product. It was washed in the order of acetonitrile (500 ml), 50% aqueous methanol solution (500 ml) to give 13.6 g (89.5%) of a yellowish brown solid product.

7) The solid product was identified as 4,4'-bis [N- (9-phenanthryl) -N-phenylamino] biphenyl having the following characteristics and structural formula (1) through various tests.

* MALDI-TOF MS: 688.80 (calculated: 688.86)

* PL: 456 nm (Excitation: 339 nm)

* ^One H-NMR (500 MHz, DMSO-d ₆ ): δ = 8.92 (d, J = 8.30 Hz, 2H), 8.86 (d, J = 8.30 Hz, 2H), 7.97 (d, J = 8.30 Hz, 2H), 7.95 (d, J = 8.30 Hz, 2H), 7.77 (s, 2H), 7.70 (t, J = 7.50 Hz, 4H), 7.62 (t, J = 7.50 Hz, 2H), 7.56 (t, J = 7.50 Hz, 2H), 7.46 and 7.01 (AB, J = 8.70Hz, 8H), 7.25 (t, J = 7.50Hz, 4H), 7.05 (d, J = 7.50Hz, 4H), 6.96 (t, J = 7.50 Hz, 2H).

* m.p. : 290.1 ° C, Tg: 146.66 ° C [Measurement by DSC]

Example 6

The reaction was carried out under the same conditions except that dibromobiphenyl was used instead of the diiodobiphenyl used in Example 5 to obtain 11.9 g (78.3%) of a yellowish brown solid product.

Comparative Example 1 (Ulman Reaction)

1) N, N'-diphenylbenzidine (3.00 g, 9.19 mmol, 97% from Acros), 9-bromophenanthrene (4.90 g, 18.4 mmol, 96% from Aldrich) in decalin (6 ml) under nitrogen atmosphere , Copper (2.60 g, 36.8 mmol), potassium carbonate (2.30 g, 18.4 mmol), and PEG (0.60 g) were added thereto, and the reaction mixture was heated up to 220 ° C. for 36 hours.

The completeness of the reaction was confirmed using TLC (EA / Hexane = 1/10), and the completeness of the reaction did not exceed 50%.

2) When the temperature of the reaction mixture was gradually lowered to 180 ° C., decalin (20 ml) was added and stirred to maintain fluidity.

3) Lower the temperature of the reaction mixture to 60 ° C, add THF (70 ml), raise the temperature to 70 ° C to dissolve the reaction mixture, perform a hot filter, and distill the filtrate under reduced pressure to obtain a solution volume of about 35 ml. 200 ml) was added, the mixture was stirred, and the product was filtered and washed with acetonitrile (500 ml) and 50% aqueous methanol solution (500 ml) in order to obtain 1.90 g of a yellowish brown solid product.

The process was not completed after 36 hours and the yield of the amine compound of formula 1 was very low, 38.4%.

Test Example 1

1) A transparent anode of ITO having a film thickness of 750 A was formed on a glass substrate having a size of 25 mm x 75 mm x 1.1 mm. The glass substrate was placed in a vacuum deposition apparatus (manufactured by Shinhan Light Vacuum) to reduce the pressure to about 10 ⁻⁷ torr. IDE 406 was then deposited into the hole injection layer, and the amine compounds of the invention prepared in Example 5 were then deposited into the hole transport layers, respectively. Alq3 was used as a green light emitting material, 1% of C545T was used as a green dopant, and Alq3 was used as an electron transport layer. Finally, the cathode was formed by depositing lithium fluoride and aluminum to prepare an organic EL device.

2) An organic electroluminescent device was manufactured in the same manner as in the above method except that α-NPD was used as the hole transport layer instead of the amine compound of the present invention.

3) The values of luminance, maximum luminance, combustion voltage (Vb), and luminous efficiency which appear when a voltage of 6 V is equally applied to each of the obtained organic EL devices are shown in Table 1 below.

Drive voltage (V) Brightness (cd / m2) Highest brightness (cd / m2) Vb Luminous Efficiency (lm / W) Amine Compounds of Example 5 6 883.5 50020 12 7.94 α-NPD 6 721.3 43650 11.5 6.12

* Vb: burn-out voltage

As a result of the above test, as shown in Table 1, the organic electroluminescent display device of the present invention manufactured by using the amine compound of the present invention, the luminance and the highest luminance or light emission than the conventional organic electroluminescent display device using the α-NPD It is excellent in efficiency, and the combustion voltage (Vb) of the present invention is also higher than the conventional combustion voltage, it can be seen that the panel of the present invention is superior in heat resistance than the conventional panel.

The amine compound of Formula 1 of the present invention has excellent solubility in organic solvents and is easy to purify. Such amine compounds are useful as constituent materials of organic electroluminescent devices and exhibit high efficiency and high glass transition temperature when used in hole transport zones, especially hole transport layers. The produced display can be used for mobile phones, PDPs and TVs.

Claims (12)

An amine compound of formula 1 useful as an organic electroluminescent material <Formula 1> An amine compound represented by Chemical Formula 1, comprising a one-step coupling reaction of reacting N, N'-diphenylbenzidine, a palladium catalyst, a phosphine catalyst, and a base with 9-halophenanthrene of Chemical Formula 3 as a starting material Manufacturing Method <Formula 3> (Wherein X represents a halogen element) The method for producing an amine compound of the formula (1) according to claim 2, wherein the halogen element of 9-halofeneanthrene and dihalobiphenyl is one selected from the group consisting of bromine and iodine. The method of claim 2, wherein the palladium catalyst is one selected from the group consisting of palladium acetate and tris (dibenzylideneacetone) dipalladium. The method of claim 2, wherein the phosphine catalyst is tri (t-butyl) phosphine. The method of claim 2, wherein the base is sodium t-butoxide. A method of preparing an amine compound of Chemical Formula 1, comprising reacting N- (9-phenanthryl) -N-phenylamine of Chemical Formula 4 with dihalobiphenyl, a palladium catalyst, a phosphine catalyst, and a base. <Formula 4> The method of claim 7, wherein the N- (9-phenanthryl) -N-phenylamine of Formula 4 is reacted with aniline, palladium catalyst, phosphine catalyst and base using 9-halophenanthrene of Formula 3 as a starting material. Method for producing an amine compound of the formula 1, characterized in that it is prepared by. The amine compound of the formula (1) according to claim 7 or 8, wherein the halogen element of the 9-halenphenanthrene and dihalobiphenyl is one selected from the group consisting of bromine and iodine. Manufacturing method. The method of claim 7 or 8, wherein the palladium catalyst is one selected from the group consisting of palladium acetate and tris (dibenzylideneacetone) dipalladium. The method of claim 7 or 8, wherein the phosphine catalyst is tri (t-butyl) phosphine. The method of claim 7 or 8, wherein the base is sodium t-butoxide.