JPH083122A - Hexaamine compound - Google Patents

Abstract

PURPOSE:To obtain the new hexaamine compound useful as an electric charge transfer substance capable of realizing organic electroluminescent elements excellent not only in luminous characteristics but also in emission stability and storage stability. CONSTITUTION:This compound is represented by formula I [R1, R2 are H, lower alkyl, lower alkoxy, substituted or nonsubstituted aryl; R3 is H, methyl, methoxy, Cl; A is 1,4-phenylene, 1,3-phenylene, group of formula II (R4 is H, methyl, methoxy, Cl), groups of formula III-IX], e.g. N,N,N'-tetrakis(4'- diphenylamino-4-biphenylyl)-O-triazine. The compound is obtained by condensing a corresponding halogenated biphenylyldiphenylamine compound with a corresponding diamine compound, or by hydrolyzing the condensation product of a corresponding halogenated biphenylylamine compound with an amide compound and subsequently condensing the obtained triamine compound with a corresponding dihalogenated product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel hexaamine compound useful as a charge transport material used in organic electroluminescent devices, electrophotographic photoreceptors and the like.

[0002]

2. Description of the Related Art Electroluminescent devices containing organic compounds as constituent elements have been studied in the past, but sufficient luminous characteristics have not been obtained. However, in recent years, the characteristics have been remarkably improved by adopting a structure in which several kinds of organic materials are laminated, and since then, studies on electroluminescent devices using organic materials have been actively conducted. This electroluminescent device having a laminated structure is manufactured by Kodak C.I. W. First reported by Tang et al. (Appl.Phys.Lett.51 (1987) 913), in which light emission of 1000 cd / m ² or more was obtained at a voltage of 10 V or less, which has been practically used in the past. There are 20 inorganic electroluminescent devices
It has been shown that it has significantly higher characteristics as compared with requiring a high voltage of 0 V or higher.

These laminated electroluminescent devices have a structure in which an organic phosphor, a charge-transporting organic material (charge-transporting material), and electrodes are stacked, and charges (holes and electrons) injected from the respective electrodes are stacked. ) Migrate in the charge transport material, and they recombine to emit light. As the organic phosphor, an 8-quinolinol aluminum complex, an organic dye that fluoresces such as coumarin, or the like is used. Further, as the charge transport material, various compounds well known as organic materials for electrophotographic photoreceptors have been studied,
For example, diamine compounds such as N, N'-di (m-tolyl) -N, N'-diphenylbenzidine and 1,1-bis [N, N-di (p-tolyl) aminophenyl] cyclohexane and 4- (N, And hydrazone compounds such as N, -diphenyl) aminobenzaldehyde-N, N-diphenylhydrazone. Furthermore, porphyrin compounds such as copper phthalocyanine have also been used.

By the way, although the organic electroluminescence device has high light emission characteristics, it is not sufficient in terms of stability during light emission and storage stability and has not been put into practical use. As one of the problems in the stability of the device when emitting light and the storage stability,
The stability of charge transport materials has been pointed out. The layer formed of the organic material of the electroluminescent device is very thin, which is one hundred to several hundred nanometers, and the voltage applied per unit thickness is very high. Further, there is also heat generation due to light emission and electric conduction, so that the charge transport material is required to have electrical, thermal or chemical stability. In addition, the charge transport layer in the device is generally in an amorphous state, but there is a phenomenon that luminescence occurs or crystallization occurs with time due to storage, which causes light emission to be hindered or device damage. Has been. In this respect, the charge transport material easily forms an amorphous state, that is, a glass state,
In addition, stable holding performance is required.

Regarding the stability of the light emitting device due to such a charge transport material, for example, many diamine compounds and porphyrin compounds are electrically and thermally stable, and high light emitting characteristics are obtained. The deterioration of the element due to crystallization has not been solved. Further, the hydrazone compound is not a preferable material because it is insufficient in electrical and thermal stability.

[0006]

DISCLOSURE OF THE INVENTION The object of the present invention is to be useful as a charge transporting material which can realize an organic electroluminescent device which is excellent not only in light emission characteristics but also in stability during light emission and storage stability, and is novel. Another object is to provide a hexaamine compound.

[0007]

According to the present invention, there is provided a hexaamine compound represented by the following general formula (1).

[0008]

[Chemical 12] (1) [In the formula, R 1 and R 2 may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, and R 3 is a hydrogen atom, Represents a methyl group, a methoxy group, or a chlorine atom, and A is the following formula

[0009]

[Chemical 13]

[0010]

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[0011]

[Chemical 15]

(In the formula, R4 represents a hydrogen atom, a methyl group, a methoxy group or a chlorine atom.)

[0013]

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[0014]

[Chemical 17]

[0015]

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[0016]

[Chemical 19]

[0017]

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[0018]

[Chemical 21]

[0019]

[Chemical formula 22] It is represented by. ]

The hexaamine compound represented by the general formula (1) of the present invention is a novel compound, which can be synthesized by condensing the corresponding halogenated biphenylyldiphenylamine compound and the corresponding diamine compound. . Alternatively, it can also be synthesized by condensing a triamine compound obtained by hydrolyzing a product obtained by the condensation reaction of a corresponding halogenated biphenylyldiphenylamine compound and an amide compound with a corresponding dihalide. These condensation reactions are methods known as the Ullmann reaction.

For example, the following formula

[0022]

[Chemical formula 23]

Where R3 is as defined above,
X represents a chlorine atom, a bromine atom or an iodine atom. However,
R3 and X are not chlorine atoms at the same time. ) Represented by 4,
A 4′-dihalogenated biphenyl compound is represented by the following formula

[0024]

[Chemical formula 24]

An equivalent amount of the diphenylamine compound represented by the formula (wherein R 1 and R 2 are as defined above) is condensed to give the following formula:

[0026]

[Chemical 25]

(Wherein R 1, R 2, R 3 and X are as defined above, provided that R 3 and X are not chlorine atoms at the same time) and the 4′-halogenated biphenylyl diphenylamine compound is can get. 4 equivalents of this 4'-halogenated biphenylyldiphenylamine compound are represented by the following formula:

[0028]

[Chemical formula 26]

Where A is as defined above and R
4 is also as defined above. The hexaamine compound of the present invention can be obtained by allowing 1 equivalent of the diamine compound represented by the formula (4) to act and condense. On the other hand, the following formula synthesized in the same manner as above for the dihalogenated biphenyl compound and the diphenylamine compound

[0030]

[Chemical 27]

4'-halogenated biphenylyldiphenylamine compound represented by the formula: wherein R1, R2, R3 and X are as defined above, provided that R3 and X are not chlorine atoms at the same time. By condensing 2 equivalents to 1 equivalent of acetamide and hydrolyzing, the following formula

[0032]

[Chemical 28]

A triamine compound represented by the formula: wherein R1, R2 and R3 are as defined above is obtained.
Further, 2 equivalents of this triamine compound are represented by the following formula

[0034]

[Chemical 29]

Where X and A are as defined above and R4 is also as defined above, provided that X and R4
Are not chlorine atoms at the same time. The compound of the present invention can also be obtained by allowing 1 equivalent of the dihalide represented by the formula (4) to act and condense. Also, of the condensation reaction,
In the condensation reaction of 2 equivalents of 4′-halogenated biphenylyldiphenylamine compound and 1 equivalent of acetamide,
Benzamide may be used instead of acetamide.

In the above-mentioned condensation reaction of various halogenated aryls with various amine compounds, the reaction is carried out without solvent or in the presence of a solvent, and nitrobenzene, dichlorobenzene or the like is used as the solvent. As the basic compound as a deoxidizer, potassium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide, sodium hydroxide and the like are used. Further, usually, the reaction is carried out using a catalyst such as copper powder or copper halide. The reaction temperature is usually 1
60 to 230 ° C.

The novel hexaamine compound obtained by the present invention easily forms a glass state and keeps it stable, and is also thermally and chemically stable, and is extremely useful as a charge transport material in an organic electroluminescence device. It is useful. Needless to say, it is a material that has a basically high charge transporting ability and is effective for an element and a system that utilize the charge transporting ability such as an electrophotographic photoreceptor.

The specific compounds of the present invention thus obtained are shown below.

[0039]

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[0040]

[Chemical 31]

[0041]

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[0042]

[Chemical 33]

[0043]

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[0044]

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[0045]

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[0046]

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[0047]

[Chemical 38]

[0048]

[Chemical Formula 39]

[0049]

[Chemical 40]

[0050]

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[0051]

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[0052]

[Chemical 43]

[0053]

[Chemical 44]

[0054]

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[0055]

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[0056]

[Chemical 47]

[0057]

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[0058]

[Chemical 49]

[0059]

EXAMPLES The present invention will be described in detail below with reference to examples.

Example 1 16.9 g (0.10 mol) of diphenylamine and 4,
4'-diyodobiphenyl 48.7 g (0.12 mol), anhydrous potassium carbonate 16.6 g (0.12 mol),
Copper powder 1.27 g (0.02 mol), nitrobenzene 20
ml was mixed and reacted at 190 to 205 ° C for 20 hours. The reaction product was extracted with 200 ml of toluene, the insoluble matter was removed by filtration, and the mixture was concentrated to dryness. This was purified by column chromatography (carrier; silica gel, eluent: toluene /
n-hexane = 1/3), N- (4′-iodo-4-biphenylyl) -N, N-diphenylamine 24.9 g
(Yield 55.6%) was obtained. Melting point is 139.5-14
It was 0.5 ° C.

Subsequently, 15.2 g (0.0) of N- (4'-iodo-4-biphenylyl) -N, N-diphenylamine
34 mol), acetamide 0.95 g (0.016 mol), anhydrous potassium carbonate 4.70 g (0.034 mol)
And 0.19 g (0.003 mol) of copper powder and 10 ml of nitrobenzene were mixed and reacted at 200 to 212 ° C for 15 hours. The reaction product was extracted with 150 ml of toluene,
The insoluble matter was removed by filtration and then concentrated to give an oily substance. The oily substance was dissolved in 120 ml of isoamyl alcohol, 1 ml of water and 1.35 g (0.024%) of 85% potassium hydroxide.
Mol) was added and the mixture was hydrolyzed at 130 ° C. After distilling off the isoamyl alcohol by steam distillation, 200 ml of toluene
The extract was washed with water, dried and concentrated. The concentrate was purified by column chromatography (carrier; silica gel, eluent; toluene / n-hexane = 1/1), and N, N-bis (4 '
-Diphenylamino-4-biphenylyl) amine 7.4
7 g (yield 71.2%) was obtained. Melting point is 212.5-2
It was 13.5 ° C.

Furthermore, 7.21 g (0.01%) of N, N-bis (4'-diphenylamino-4-biphenylyl) amine
1 mol), 2.03 g of 4,4'-diiodobiphenyl
(0.005 mol), anhydrous potassium carbonate 1.52 g
(0.011 mol), copper powder 0.13 g (0.002 mol), and nitrobenzene 10 ml are mixed, and 195-21
The reaction was carried out at 0 ° C for 15 hours. The reaction product is toluene 1
The mixture was extracted with 00 ml, the insoluble matter was filtered off, and after concentration, 120 ml of n-hexane was added to take out crude crystals. The crude crystals were purified by column chromatography (carrier; silica gel, eluent; toluene / n-hexane = 1/1), N,
4.16 g of N, N ', N'-tetrakis (4'-diphenylamino-4-biphenylyl) benzidine (yield; 5
6.9%) was obtained. 188-191 ° C obtained
And showed no clear melting point. The elemental analysis results and infrared absorption spectrum (measuring instrument; IR-700 manufactured by JASCO Corporation, measuring method; KBr tablet method) are as follows. Elemental analysis value; Carbon: measured value 88.78% (theoretical value 8
8.74%), hydrogen: measured value 5.58% (theoretical value 5.5)
1%), nitrogen: measured value 5.69% (theoretical value 5.75)
%). Infrared absorption characteristics; 3028 cm ^-1 , 1591 cm ^-1 ,
1488 cm ^-1 , 1319 cm ^-1 , 1275 cm
^-1 , 1176cm ^-1 , 818cm ^-1 , 753cm
^-1 , 697 cm ^-1 .

Example 2 20.3 g (0.12 mol) of diphenylamine and 4,
40.9 g (0.15 mol) of 4'-diiodobiphenyl, 19.3 g (0.14 mol) of anhydrous potassium carbonate,
Copper powder 1.52g (0.024mol), nitrobenzene 2
0 ml was mixed and reacted at 190 to 205 ° C for 21 hours. The reaction product was extracted with 200 ml of toluene, the insoluble matter was removed by filtration, and the mixture was concentrated to dryness. This was purified by column chromatography (carrier; silica gel, eluent: toluene / n-hexane = 1/3) and N- (4'-iodo-4-).
Biphenylyl) -N, N-diphenylamine 29.0 g
(Yield 54.1%) was obtained. Melting point is 139.5-14
It was 0.5 ° C.

Subsequently, N- (4'-iodo-4-biphenylyl) -N, N-diphenylamine 22.8 g (0.0
51 mol), o-tolidine 2.55 g (0.012 mol), anhydrous potassium carbonate 6.91 g (0.050 mol)
Further, 0.64 g (0.001 mol) of copper powder and 10 ml of nitrobenzene were mixed and reacted at 200 to 212 ° C for 28 hours. The reaction product was extracted with 160 ml of toluene,
After removing the insoluble matter by filtration, the mixture was concentrated to dryness. The obtained solid substance was purified by column chromatography (carrier; silica gel, eluent; toluene / n-hexane = 1/1), N, N,
N ', N'-tetrakis (4'-diphenylamino-4
-Biphenylyl) -o-tolidine 9.94 g (yield; 5
5.6%) was obtained. The obtained product melted at 196 to 203 ° C and did not show a clear melting point. The elemental analysis values and infrared absorption characteristics are as follows. Elemental analysis value; Carbon: measured value 88.67% (theoretical value 8
8.68%), hydrogen: measured value 5.78% (theoretical value 5.6).
8%), nitrogen: measured value 5.56% (theoretical value 5.64)
%). Infrared absorption characteristics; 3026 cm ^-1 , 1589 cm ^-1 ,
1486 cm ^-1 , 1314 cm ^-1 , 1270 cm
^-1 , 1176cm ^-1 , 816cm ^-1 , 752cm
^-1 , 696 cm ^-1 .

Example 3 20.3 g (0.12 mol) of diphenylamine and 3,
3'-dimethyl-4,4'-diiodobiphenyl 65.
1 g (0.15 mol), anhydrous potassium carbonate 19.3 g
(0.14 mol), 1.52 g (0.024 mol) of copper powder, and 20 ml of nitrobenzene are mixed to obtain 190-20
The reaction was carried out at 5 ° C for 21 hours. The reaction product is toluene 2
The mixture was extracted with 00 ml, the insoluble matter was removed by filtration, and the mixture was concentrated to dryness. This was purified by column chromatography (carrier; silica gel, eluent; toluene / n-hexane = 2/7),
32.6 g (yield 57.2%) of N- (3,3'-dimethyl-4'-iodo-4-biphenylyl) -N, N-diphenylamine was obtained.

Subsequently, N- (3,3'-dimethyl-4'-
Iodo-4-biphenylyl) -N, N-diphenylamine 24.2 g (0.051 mol), o-tolidine 2.5
5 g (0.012 mol), anhydrous potassium carbonate 6.91 g
(0.050 mol), copper powder 0.64 g (0.001 mol), and nitrobenzene 10 ml are mixed, and 200-21
The reaction was carried out at 2 ° C for 30 hours. The reaction product is toluene 1
The mixture was extracted with 50 ml, the insoluble matter was removed by filtration, and the mixture was concentrated to dryness. The obtained solid is purified by column chromatography (carrier; silica gel, eluent: toluene / n-hexane = 3/4) to give N, N, N ', N'-tetrakis (3,3).
9.48 g of 3'-dimethyl-4'-diphenylamino-4-biphenylyl) -o-tolidine (yield; 49.3)
%) Was obtained. The obtained product melted at 196 to 212 ° C and did not show a clear melting point. The elemental analysis values and infrared absorption characteristics are as follows. Elemental analysis value; Carbon: Measurement value 88.53% (theoretical value 8
8.46%), hydrogen: measured value 6.24% (theoretical value 6.2)
9%), nitrogen: measured value 5.21% (theoretical value 5.25)
%). Infrared absorption characteristics; 3026 cm ^-1 , 1589 cm ^-1 ,
1486 cm ^-1 , 1314 cm ^-1 , 1270 cm
^-1 , 1176cm ^-1 , 816cm ^-1 , 752cm
^-1 , 696 cm ^-1 .

Further, the usefulness of the compounds found from the present invention will be explained by specific application examples.

Application Example 1 On a thoroughly washed ITO electrode, the compound obtained in Example 1 (general formula (1); R1 = H, R2 = H, R3 =
H, A =

[0069]

Embedded image

, R4 = H) as a charge transport material,
It was deposited by vacuum deposition at a rate of nm / sec to a thickness of 50 nm. On the vapor-deposited film, purified tris (8-quinolinol) aluminum complex as a luminescent material was vapor-deposited by vacuum vapor deposition at a rate of 0.1 nm / sec to a thickness of 50 nm. Further, a Mg / Ag electrode having a thickness of 100 nm is formed on this film by vacuum vapor deposition, and EL
A device was produced. These vapor depositions were continuously performed without breaking the vacuum on the way. The film thickness was monitored by a crystal oscillator. Immediately after the device was manufactured, the electrode was taken out in dry nitrogen, and the characteristics were continuously measured. The emission characteristics of the device are defined by the emission brightness when a current of 100 mA / cm ² is applied, and the emission life is 100 cd / c when a current of 200 cd / m ² is continuously applied.
It was the time to reach m ² . Further, the storage stability was defined as the time until the luminance became half of the initial light emission characteristics after applying a current of 20 mA / cm ² after leaving it in the dry air at room temperature for a certain time. As a result of the measurement, the emission characteristic is 1400 cd.
/ M ² , emission life is 700 hours, storage stability is 210
It was 0 hours. As a charge transport material, for comparison,
Using N, N'-di (m-tolyl) -N, N'-diphenylbenzidine, an EL device was prepared under the same conditions and its characteristics were examined. The light emission characteristics, the light emission life, and the storage stability were 2200 cd / m ² , 220 hours, and 460 hours, respectively.

[0071]

INDUSTRIAL APPLICABILITY The novel hexaamine compound found by the present invention effectively functions as a charge-transporting material, easily forms a glass state and stably maintains the glass state, and is thermally and chemically Since it is stable, it is a substance which is particularly useful as a charge transport material in an organic electroluminescence device.

Claims (1)

[Claims] 1. A hexaamine compound represented by the following general formula: [Wherein R 1 and R 2 may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a substituted or unsubstituted aryl group, and R 3 is a hydrogen atom, a methyl group, a methoxy group, Or represents a chlorine atom, and A is the following formula: Embedded image [Chemical 4] (In the formula, R4 represents a hydrogen atom, a methyl group, a methoxy group or a chlorine atom.) [Chemical 6] [Chemical 7] Embedded image [Chemical 9] [Chemical 10] [Chemical 11] It is represented by. ]