JPH11255700A - Acetylacetone-based metal complex and its synthesis and organic multilayered type electroluminescent element using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound useful as a luminescent layer of an organic multilayer type EL element exhibiting sufficient luminescence at low voltage and having long life by introducing an atomic group having a specific structure into a ligand of β-diketone. SOLUTION: This acetylacetone-based metal complex comprises a 1,3-diketone derivative of formula I [R1 and R2 are each an alkyl and/or an allyl compound and at least either one comprises a conjugated double bond; M is Al, Zn, Mn, Ni, Cr, Co, Eu, Fe, Mg or Be; (n) is an integer of 2-4], e.g. a complex of formula II. The metal complex of formula I is obtained by introducing an atomic group selected from benzene and its derivative, an aromatic compound having one or more benzene rings and its derivative, a heterocyclic compound and its derivative and a conjugated compound and its derivative into a ligand of β-diketone and reacting the ligand with a proper metal. Thereby, β-diketone compound emitting fluorescence can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel acetylacetone compound, more specifically to a metal complex having an acetylacetone ligand, and to a novel method for synthesizing the acetylacetone compound, and to a novel acetylacetone compound. The present invention relates to an application to an organic multilayered electroluminescence device (EL device) utilizing the light emission characteristics of a metal complex having a ligand.

[0002]

2. Description of the Related Art For a long time, 1,3-diketone (β-diketone) compounds represented by acetylacetone have been well known. These compounds are generally prepared by reacting a carboxylic acid ester with a ketone using sodium ethylate, sodium amide or the like as a catalyst, a ketone and an acid anhydride using boron trifluoride as a catalyst, an α-acyl β-ketonate It is synthesized by a method such as decomposing a derivative with a dilute acid or dilute alkali. Also, β-
Diketones are also well known for producing extremely stable chelates. For example, acetylacetone is Na, K, Ti,
It forms a complex with numerous metals such as Au, Mn, and Cs. None of these conventionally known β-diketone compounds having fluorescence has been synthesized. Naturally, most types of complexes with these metals were nonfluorescent.

[0003]

SUMMARY OF THE INVENTION A β-diketone compound which has been conventionally considered to have no fluorescence has been found to emit a fluorescent compound. Although it is said that the development of applications will be carried out, no compound that emits fluorescence with β-diketone compounds has yet been found, and the emergence of these novel fluorescent β-diketone compounds is expected. I have.

[0004]

As a result of intensive studies by the present inventors, a β-diketone derivative emitting fluorescence which has not been found to date has been found by introducing an atomic group having a specific structure into a ligand of β-diketone. Was discovered and synthesized. The first of the features of the present invention is the discovery of a β-diketone derivative which emits fluorescence, which has been considered to be non-existent, and the discovery of a novel combination of ligands capable of exerting its properties. It is the establishment of a new synthesis step for a method for synthesizing a compound or the like.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The compound of the present invention is based on the introduction of an atomic group having a specific structure into a ligand of β-diketone. Introduce to one or both.
By introducing a ligand having a conjugated double bond, a β-diketone that emits unprecedented fluorescence can be obtained. When describing the atomic groups introduced into the present invention, cyclic compounds,
One or two of heterocyclic compounds and chain compounds, that is, the same compound or different compounds may be used, but at least an atomic group having a conjugated double bond must be introduced. Examples of the cyclic compound introduced into the present invention include benzene and its derivatives, aromatic compounds having one or more benzene rings such as naphthalene, anthracene, phenanthrene, pyrene and coronene and derivatives thereof, and conjugates such as biphenyl and distyryl. -Based compounds and derivatives thereof, examples of heterocyclic compounds include furan, thiofuran, oxazole,
Examples of thiooxazole, carbazole and its derivatives and chain compounds include alkane, ethylene and diene types having 1 to 12 carbon atoms. The β-diketone into which these atomic groups are introduced emits fluorescence, and these β-diketones are added to Al, Zn, Mn, Ni, Cr, Co, Eu, Fe, M
It has been found that a metal complex obtained by reacting a metal such as g, Be or the like exhibits a very efficient light-emitting phenomenon, so that a light-emitting element for an organic EL element is used as one of applications of the present invention. It was figured out.

The structure of the β-diketone used in the present invention is exemplified as follows.

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Various metals are coordinated to these β-diketones, and the metals to be coordinated are Al, Z
n, Mn, Ni, Cr, Co, Eu, Fe, Mg, Be
And luminescent materials having different color tones can be obtained depending on the combination of the structure of β-diketone and the metal to be coordinated. At this time, the coordination number of β-diketone is 2 to 6 according to the valence of the metal to be coordinated. A metal complex in which these various metals are coordinated has a high luminous efficiency and emits bright light even at a low voltage.

Here, the electroluminescent material is described as follows.
For example, self-activated ZnS and CdS, and Al ₂ O ₃ activated with a transition metal have been used as electroluminescent materials.
And various other inorganic compounds are used for specific applications such as instrument panels and indicator lights, but generally have the disadvantage of low luminance and high drive voltage. For the purpose of resolving these inconveniences, studies using organic compounds as electroluminescent materials have been actively conducted, and various compounds have been proposed. In general, an electroluminescence using an organic substance has a simplest structure including a light emitting layer and a pair of opposed electrodes sandwiching the layer. In light emission, when an electric field is applied between both electrodes, electrons are injected from the cathode side, holes are injected from the anode, and
This is a phenomenon in which the electrons recombine with holes in the light emitting layer, and energy is emitted as light when the energy level returns from the conduction band to the valence band. Conventionally, various types of electroluminescence have been reported, such as a device having a two-layer structure in which an organic fluorescent dye is used as a light-emitting layer and laminated with an organic charge transport compound, and a device using a polymer as a light-emitting material. A relatively simple general structure of an organic EL device known today is shown in FIG. 1, which has a layered structure of a cathode, a light emitting layer, an organic hole transport layer, an anode, and a substrate. As another example, there is an example in which a layer structure of a cathode, an electron transport layer, a light emitting layer, an organic hole transport layer, an anode, and a substrate is added in addition to an electron transport layer.

Generally, the cathode is made of aluminum (Al), magnesium (Mg), indium (In), silver (A
g), etc., or Al-Mg, Ag-M
g, an alloy of these metals such as Al-Li, and a material having a small work function is used.

For the light emitting layer, a substance emitting fluorescence is used. For example, there are various compounds such as anthracene, naphthalene, phenanthrene, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, and coumarin derivative.
Specifically, tris (8-quinolinol) aluminum, bis (8-quinolinol) magnesium, tris (5-chloro-8-quinolinol) gallium and the like can be exemplified.

As the organic hole transport layer, N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1
-Biphenyl 4,4'-diamine (TPD), copper phthalocyanine, 4,4'-4} -tris- {N- (3-methylphenyl) -N-phenylamino} triphenylamine (MTDATA) and the like. I can do things.

As the electron transporting layer, fluorenone, anthraquinodimethane, diphenoquinone, [2- (4'-t-
(Butylphenyl) -5- (biphenyl) -1,3,4-
Oxadiazole] and the like.

The anode is made of indium tin oxide (IT)
A transparent conductive material having a large work function such as O) or tin oxide is used.

The substrate only needs to have thermal and mechanical strength and be transparent. For example, a highly transparent resin such as a glass substrate, a polyethylene plate or a polypropylene plate can be used. For the formation of each of these layers, an appropriate method such as vacuum evaporation, sputtering, and spin coating can be applied.

The thickness of each layer is not particularly limited, but each layer must be set to an appropriate thickness. If the film thickness is too large, a high voltage is required to obtain a certain luminance, and the efficiency is reduced. Deterioration further advances due to high voltage,
The disadvantage is that the life is shortened. On the other hand, if the film thickness is too small, sufficient light emission may not be obtained even when an electric field is applied due to generation of pinholes or the like. The thickness of each layer in the present invention is 1
It is desirably about 0 nm to 1000 mμ.

The present invention is characterized by providing a novel luminous body which can be used for the luminous layer, among them, and other known materials can be used for the other cathode, organic hole transport layer, anode and substrate. . The organic multilayer EL device incorporating the β-diketone-based metal complex of the present invention exhibits sufficient light emission at a low voltage of 1 to 2 V, and can extend the life to about 50,000 hours.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Synthesis-1 Synthesis method of 1,3Di (2-thiofurane) -1,3-Propanedione (hereinafter abbreviated as DTP) 2-acetylthiophene was placed in a 500 ml four-necked flask equipped with a mechanical stirrer, a calcium chloride tube and a cooling tube. 10 g (7.93 × 10 ^-2 mol) and 2-
12.38 g of thiophenecarboxylic acid (7.93 × 10 ⁻²
mol) and 6.18 g of sodium amide (1.58 ×
(10 ^-1 mol) 300 ml of dehydrated THF was added as a solvent and stirred at 60 ° C. for 90 hours. The reaction solution was concentrated with an evaporator, acidified with an aqueous HCl solution, extracted with diethyl ether, and the ether layer was concentrated. Then, the crystals were recrystallized from 99.5% ethanol to obtain a yellow target product DTP. The reaction formula is shown below.

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Yield: 65% m.p. p. 95-98 ° C IR (KBr) See FIG. 2 ¹ H-NMR (CDCl ₃ ) ··· See FIG. 3 UV (CH ₃ CN) ········ Refer to FIG. 4 This compound was confirmed from FIG. 2, FIG. 3, and FIG.

-2 Method for synthesizing complex Al (DTP) ₃ DTP2.D was added to a 100 ml four-necked flask equipped with a mechanical stirrer, a calcium chloride tube and a condenser.
12g (8.98 × 10 ⁻⁸ mol) as a solvent.
Add 20 ml of 5% ethanol, and add 1N-Na
2 ml of OH was added to make a weak base of pH 8-9. 2.0 g of aluminum sulfate 14-18 hydrate was added to this
in a dropping funnel and dropped.
C. and stirred for 1 hour. Then a large amount of crystals were deposited. The crystals were filtered with Nutsche, and unreacted DTP was removed with distilled water and ethanol. Then, the reaction product was recrystallized from benzene to obtain a yellow target product complex Al (DTP) ₃ . The reaction formula is shown below.

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Yield: 58% m.p. p. 300 ° C or higher IR (KBr) See FIG. 5 ¹ H-NMR (CDCl ₃ )・ See FIG. 6 UV (CH ₃ CN) ・ ・ ・ ・ ・ ・ ・ ・ ・ See FIG. 7 This compound was confirmed from FIG. 5, FIG. 6 and FIG.

-1- 2-Naphtyl-4-Dimethlaminobenzo-
Synthesis Method of 1,3-Propanedione (hereinafter abbreviated as NDP) The synthesis method and purification method are the same as -1. The reaction formula is shown below.

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Yield 65% m. p. 321.1 ° C IR (KBr) See FIG. 8 ¹ H-NMR (CDCl ₃ ) ···· See FIG. 9 UV (CH ₃ CN) ········ Refer to FIG. 10 The present compound was confirmed from FIG. 8, FIG. 9 and FIG.

-2 Synthesis method of complex Zn (NDP) ₂ The synthesis method and purification method are the same as in -2. The reaction formula is shown below

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Yield: 56% m. p. 300 ° C or higher IR (KBr) See FIG. 11 ¹ H-NMR (CDCl ₃ ) - Figure 12 Referring UV (CH ₃ CN) ········· 13 see Figure 11, Figure 12, the compound than 13 were confirmed.

-1 2-Thiofurano-4-dimethylaminobe
Synthesis method of nzo-1,3-Propanedione (hereinafter abbreviated as TANC) The synthesis method and purification method are the same as -1. The reaction formula is shown below.

Embedded image The yield of the synthesized compound was 73%.

-2 Synthesis method of complex Al (TANC) ₃ The synthesis method and purification method are the same as in -2. The reaction formula is shown below

Embedded image The yield of the synthesized compound was 78%.

2. Fabrication of EL element ITO (anode) / TPD (1000Å) /
Complex of the present invention (1000 °) / cathode (Al-Li200
EL devices were manufactured in the order of 0 °). The structure of the device at this time is the same as that described in the specification. TPD is an abbreviation of the compound shown below, and its structural formula is shown below. (N, N '
-diphenyl-N, N '-(3-methylphenyl) 1,1-biphenyl-4,4 ・ di
amine)

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3. EL element measurement results

[Table 1]

[0029]

As described above, according to the present invention, by using the novel acetylacetone-based metal complex discovered by the present inventors for the light emitting layer, sufficient light emission can be exhibited at a low voltage, and the lifetime is long. An organic multilayer EL device can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a general structure of an organic multilayer EL device.

FIG. 2: 1,3Di (2-thionyl) -1,3-P synthesized in Example
It is an IR (KBr) chart of ropanedione (DTP).

FIG. 3 shows 1,3Di (2-thionyl) -1,3-P synthesized in Example
¹ H-NMR (CDCl ₃ ) of ropanedione (DTP)
It is a chart.

FIG. 4 shows 1,3Di (2-thionyl) -1,3-P synthesized in Example
It is a UV (CH ₃ CN) chart of ropanedione (DTP).

FIG. 5 is an IR (KBr) chart of a complex Al (DTP) ₃ synthesized in Examples.

FIG. 6 shows the results of complex Al (DTP) ₃ synthesized in Examples.
¹ H-NMR (CDCl ₃₎ is a chart.

FIG. 7 is a UV (CH ₃ CN) chart of a complex Al (DTP) ₃ synthesized in Example.

FIG. 8: 2-Naphtyl-4-Dimethlami synthesized in Example
IR (KBr) of nobenzo-1,3-Propanedione (NDP)
It is a chart.

FIG. 9: 2-Naphtyl-4-Dimethlami synthesized in Example
¹ H-NMR of nobenzo-1,3-Propanedione (NDP)
It is a (CDCl ₃₎ chart.

FIG. 10: 2-Naphtyl-4-Dimethla synthesized in Example
UV of minobenzo-1,3-Propanedione (NDP) (CH ₃
10 is a CN) chart.

FIG. 11 shows a complex Zn (NDP) ₂ synthesized in Example.
3 is an IR (KBr) chart.

FIG. 12 shows a complex Zn (NDP) ₂ synthesized in an example.
^{1 is} a ¹ H-NMR (CDCl ₃ ) chart.

FIG. 13 shows a complex Zn (NDP) ₂ synthesized in Example.
5 is a UV (CH ₃ CN) chart.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C07F 5/06 C07F 5/06 D 11/00 11/00 A 13/00 13/00 A 15/02 15/02 15/04 15/04 15/06 15/06 C09K 11/06 660 C09K 11/06 660 H05B 33/14 H05B 33/14 B

Claims (11)

[Claims] 1. A compound of the general formula An acetylacetone-based metal complex comprising a 1,3-diketone derivative represented by the formula: 2. The compound according to claim 1, wherein the allyl compound is benzene or a derivative thereof, an aromatic compound having one or more benzene rings and a derivative thereof, a heterocyclic compound or a derivative thereof, a conjugated compound or a compound selected from the group consisting of a derivative thereof. The acetylacetone-based metal complex according to claim 1, wherein the complex is at least one kind. 3. The acetylacetone-based metal complex according to claim 2, wherein the heterocyclic compound and its derivative are at least one of thiofuran, oxazole, thiooxazole and carbazole. 4. The method according to claim 1, wherein the aromatic compound and its derivative are The acetylacetone-based metal complex according to claim 2, wherein the acetylacetone-based metal complex has a structure represented by the following formula. 5. An aromatic compound or a derivative thereof having 2 to 2 rings.
5. The acetylacetone-based metal complex according to claim 2, wherein the complex is 5. 6. A compound of the general formula An organic multilayer-type electroluminescence device characterized by using an acetylacetone-based metal complex represented by the formula (1) for a light emitting layer. 7. A compound of the general formula A method for synthesizing an acetylacetone-based metal complex, which is synthesized via an intermediate comprising a 1,3-diketone derivative represented by the following formula: 8. The compound according to claim 1, wherein the allyl compound is benzene or a derivative thereof, an aromatic compound having one or more benzene rings or a derivative thereof, a heterocyclic compound or a derivative thereof, a conjugated compound or a compound selected from the group consisting of a derivative thereof. The method for synthesizing an acetylacetone-based metal complex according to claim 7, wherein the metal complex is at least one kind. 9. The method for synthesizing an acetylacetone-based metal complex according to claim 7, wherein the heterocyclic compound and its derivative are at least one of thiofuran, oxazole, thiooxazole and carbazole. 10. An aromatic compound and its derivative are represented by the following formula: The method for synthesizing an acetylacetone-based metal complex according to claim 7, wherein the metal complex has a structure represented by the following formula: 11. An aromatic compound or a derivative thereof having 2 rings
The method for synthesizing an acetylacetone-based metal complex according to claim 7, wherein