JP2000357588A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily control luminous wavelength, and enhance luminous effi ciency, heat resistance and the like by including a metal complex compound having a compound with a specific basic skeleton in at least one layer of plural organic compound layers located between electrodes as a ligand. SOLUTION: A metal complex compound having a compound having a basic skeleton shown in formula I is included as a ligand. An electroluminescent element preferably contains the metal complex compound having at least one layer of organic compound layers represented by formula II having a central metal represented by M, at least one ligand of one pyridylphenol skeleton, and zero to (m) auxiliary ligands represented by L. The element is formed by stacking a first electrode, an organic compound layer emitting light by applying an electric field, and a second electrode in order on a transparent board. Even by controlling the kind of the central metal, and the presence or kind of the auxiliary ligand, luminous wavelength, heat resistance, and luminous efficiency can be controlled, and the electroluminescent element having long life, high efficiency, and various luminescent colors is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device (hereinafter, referred to as an organic EL device), and particularly to an organic compound material used for the device.

[0002]

2. Description of the Related Art An organic EL device is formed on a transparent glass substrate.
A transparent first electrode (for example, ITO), an organic compound layer containing an organic compound having strong fluorescence, and a metal (for example, Mg) second electrode are sequentially laminated.

The organic compound layer has, for example, a three-layer structure in which a hole transporting functional molecular layer, a light emitting functional molecular layer, and an electron transporting functional molecular layer are sequentially stacked, and emits light by applying an electric field to a pair of electrodes. . That is, when holes are injected from the first electrode and electrons are injected from the second electrode, the injected holes and electrons move in the organic compound layer, collide and recombine, and disappear. The energy generated by the recombination is used to generate an excited state in the light-emitting molecule, whereby the organic EL element emits fluorescence.

[0004] Such an organic EL device is self-luminous, has no restriction on the viewing angle, can be driven at a low voltage, and can respond at high speed.
It has excellent characteristics as compared with currently known displays such as a liquid crystal display, a plasma display, and an inorganic electroluminescent display.

[0005]

At present, as an organic light emitting material, a quinolinol complex having both an electron transport function and a light emitting function is known. This quinolinol complex is
For example, as Alq ₃ , the following chemical formula (3)

Embedded image And a quinolinol complex of aluminum as shown in Table 1.

An organic EL device using this quinolinol complex emits green light and achieves a somewhat high luminance. However, they do not meet the requirements for practical use in terms of luminance, luminous efficiency, lifetime, and the like. Further, materials that exhibit other desired emission colors in realizing a full-color display or the like have not been optimized.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a novel organic compound having excellent characteristics, and to provide an organic EL device using the organic compound. .

[0008]

According to the present invention, there is provided an organic EL device having one or more organic compound layers between electrodes, wherein at least one of the organic compound layers is coordinated. As a child, chemical formula (1)

Embedded image And a metal complex compound having, as a ligand, a compound having a basic skeleton represented by

Further, in the organic EL device according to the present invention,
An organic electroluminescent device comprising one or more organic compound layers between electrodes, wherein at least one of the organic compound layers has a chemical formula (2)

Embedded image , A central metal represented by M, one or more l ligands of a pyridylphenol skeleton, and zero or more m L
And a metal complex compound comprising: an auxiliary ligand represented by

The compound having a pyridylphenol skeleton represented by the chemical formula (1) can be coordinated to the central metal M of the complex with an appropriate distance and directionality. The metal complex having such a ligand exhibits an excellent light emitting function, and is also excellent in molecular stability, heat resistance, luminous efficiency, and the like. Therefore, by using such a metal complex as an organic compound material of an organic EL device, the emission luminance of the device can be improved and the life of the device can be improved.

Further, in the above metal complex, if the substituents X _{1 to} X ₈ of the ligand are selected, the characteristics of the metal complex can be changed. Depending on the substituent selected, the emission wavelength of the metal complex can be adjusted, and the emission efficiency and stability can be improved. If the rigidity of the ligand is increased by the substituent of the introduced ligand to suppress the molecular motion, the stability of the metal complex in the form of a thin film can be improved, and the organic E
It is possible to prevent the deterioration of the L element and improve the stability. Also, the emission wavelength can be adjusted. Furthermore, when an electron donating or electron withdrawing group is introduced as a substituent,
By selecting the type, the emission wavelength can be adjusted,
An organic compound material that emits various colors such as red, blue, and green can be realized. In addition, by introducing these electron-donating and electron-withdrawing substituents into the metal complex, the electric polarization of the metal complex, which is a light-emitting molecule, can be made easier and the luminous efficiency can be improved. Can also.

The emission wavelength can also be adjusted by selecting the number of ligands, the central metal M of the metal complex, the type of auxiliary ligand L, the number thereof, and the like. It can also be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter, referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 shows an organic E according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a schematic structure of an L element. This element is configured by sequentially laminating a first electrode 12, an organic compound layer 14 emitting light by application of an electric field, and a second electrode 16 on a transparent substrate 10.

As the transparent substrate 10, a glass substrate, a transparent ceramics substrate, a diamond substrate or the like can be used. As the first electrode 12, a transparent electrode having high light transmittance and conductivity is used. For example, ITO (In
For example, a thin film material such as dium tin oxide, SnO ₂ , In ₂ O ₃ , or polyaniline can be used.

The organic compound layer 14 is a portion that emits light when an electric field is applied, such as a single-layer structure of a light-emitting layer, a two-layer structure of a hole-transport layer and a light-emitting layer, a hole-transport layer, a light-emitting layer, and an electron-transport layer. And a three-layer structure. In addition, it may be composed of a single layer or a multilayer. The thickness of the organic compound layer 14 is several tens to several hundreds nm.

In the embodiment of the present invention, an organic compound represented by the chemical formula (2) is used as a light emitting functional material of the organic compound layer 14. The compound of formula (2) described below is
It is a metal complex containing 1 compound (l ≠ 0) as a ligand using a compound of the formula (1) having pyridylphenol as a basic skeleton. In the chemical formula (2), M is a central metal of the complex, L is an auxiliary ligand different from a ligand having pyridylphenol as a basic skeleton, and m is the number of auxiliary ligands L (m ≧
0). The metal complex compound represented by the chemical formula (2) exhibits excellent characteristics as a light emitting functional molecule, and can alone constitute a light emitting layer of an organic EL device. For example, an organic EL element can be formed by forming a light emitting layer using the metal complex compound alone between the hole transport layer and the electron transport layer. In addition, since this metal complex has an electron transporting function in addition to a light emitting function, a light emitting layer which also serves as an electron transporting layer using the metal complex of the above chemical formula (2) without using other electron transporting molecules. And a two-layer structure with a hole transporting layer formed using a hole transporting functional molecule.

The metal complex compound can be used by dispersing it by doping another host substance. In order to realize higher emission luminance as an organic EL device, it is preferable to manufacture the device by doping the metal complex compound of the chemical formula (2) with the electron transporting molecule or the hole transporting molecule by several percent. .

The electron transporting functional molecule which can be used together with the metal complex according to the present invention includes A represented by the above formula (3).
lq ₃ and derivatives thereof. As the hole transporting functional molecule, for example, the chemical formula (4)

Embedded image Triphenylamine dimer (TPD) as shown in
And copper phthalocyanine. However, it is not limited to these materials.

In the organic EL device shown in FIG. 1, the second electrode 1 is placed on the organic compound layer 14 containing the metal complex compound.
6 is formed, and as the second electrode 16, M
g, Ag, etc., or Li, B, Be, Na, Mg, A
Alloys containing metals with low ionization potential such as l, K, Ca (eg, Mg-Ag, AlLi, LiF
/ Al) or the like.

In the organic EL device having the above structure, the first electrode 12 is used as an anode, the second electrode 16 is used as a cathode, and holes and electrons are injected into the organic compound layer 14 from these electrodes. The injected holes and electrons are recombined in the organic compound layer 14, and the light emitting material such as the metal complex of the present invention is excited, and the fluorescence of the color resulting from this metal complex is obtained.

Hereinafter, the metal complex compound represented by the chemical formula (2) according to the present invention will be described in detail. This compound
The compound has a pyridylphenol skeleton compound represented by the chemical formula (1) as a ligand. Since pyridylphenol can coordinate to the metal M with an appropriate distance and directionality, a complex using this as a ligand has excellent stability and luminous efficiency. Therefore, by using this metal complex as an organic compound material of an organic EL device, the brightness of the device is improved,
Further, the life of the element can be improved.

In the chemical formulas (1) and (2), X _{1 to} X ₈ of the pyridylphenol skeleton as a ligand are substituents, and these X _{1 to} X ₈ are an alkyl group, an aryl group, an allyl group. , Alkene group, alkyne group, alkoxy group, hydroxy group, hydroxyl group, hydroxylate group, thiocarboxy group, dithiocarboxy group, sulfo group, sulfino group, sulfeno group, oxycarbonyl group, haloformyl group, carbamoyl group, hydrazinocarbonyl Group, amidino group, cyano group, isocyanate group, cyanato group, isocyanato group, thiocyanato group, isothiocyanato group, formyl group, oxo group, thioformyl group, thioxo group, mercapto group, amino group, imino group, hydrazino group, allyloxy group, Sulfide group, hydrogen atom, halogen group, nitro group, A functional group containing a partially substituted product thereof can be used. Further, X _{1 to} X ₈ may be a bifunctional substituent such as an aromatic compound or a chain compound in which the substituents are bonded to each other. Further, the aromatic compound or the chain compound may have any of the above functional groups.

In the metal complex compound represented by the chemical formula (2), M is a metal serving as the center of the complex, and the metal M exists in the complex in a positively charged state. As the metal M, zinc, germanium, aluminum, beryllium, and the like can be used, and other than these, any metal that can be a positive ion may be used.

The auxiliary ligand represented by L in the chemical formula (2) need not always be present, but when used, has an electrically neutral or negative charge and can form a complex with the metal M. Any compound may be used. For example, chemical formula (7)

Embedded image Quinolinol as shown in the chemical formula (8)

Embedded image Phenol as shown in the chemical formula (9)

Embedded image For example, phenanthroline as shown in (1) can be used.

In the above metal complex, for example, the following chemical formulas (i) to (viii)

Embedded image

Embedded image There exists a compound having a structure as shown in FIG.

Chemical formulas (i) to (vi) are complexes in which Zn is the central metal and two pyridylphenol skeleton compounds are ligands (l = 2). The chemical formulas (vii) and (viii) have Al as the central metal, and the chemical formulas (vi
i) comprises three pyridylphenols as ligands (l = 3). The chemical formula (viii) has a structure including two pyridylphenols and one 4-phenylphenol as the auxiliary ligand L.

The properties of the metal complex compound represented by the general formula (2) can be changed by the ligand. For example, the luminous efficiency, stability, crystallinity, and the like of the metal complex change depending on the substituent introduced into the ligand. Hereinafter, the relationship between the substituent of the ligand to be introduced and the characteristics of the substituent and the metal complex will be described.

As the ligand of the pyridylphenol skeleton of the metal complex, a structure in which a phenol ring and a pyridine ring are crosslinked can be employed. For example, it has a structure in which substituents X ₄ and X _{5 of} a pyridylphenol skeleton are bonded to each other, and a phenol ring and a pyridine ring are crosslinked. The following chemical formulas (12) and (13)

Embedded image

Embedded image Are examples of the ligand having a crosslinked structure. Such a ligand having a crosslinked structure in which two rings of pyridylphenol are crosslinked has increased rigidity as compared with an uncrosslinked structure, and the stability of the metal complex, particularly the heat stability, is improved. For example, the metal complex represented by the chemical formula (ii) has a ligand represented by the chemical formula (12) in which a phenol ring and a pyridine ring are cross-linked by a 5-membered ring. When a metal complex represented by the chemical formula (ii) is used as a material for an organic EL device, the heat resistance and the life of the device can be improved. Further, by bridging the phenol ring and the pyridine ring, the planarity of the ligand changes, and the conjugate state of the ligand changes. Therefore, it becomes possible to change the emission color of a metal complex having a ligand without cross-linking. In addition, the emission color of the complex also differs due to the difference in the cross-linking structure. For example, a metal complex having the chemical formula (12) as a ligand and a metal complex having the chemical formula (13)
With the complex having as a ligand, the complex using the chemical formula (13) having a larger number of carbon atoms in the cross-linking portion tends to have a shorter emission wavelength. By adopting a cross-linked structure as the ligand and changing the cross-linked structure as described above, the emission color of the metal complex can be adjusted.

In the metal complex of the present invention, when a bulky group, for example, a bulky aliphatic group or an aromatic group is used as the substituent X _{1 to} X ₈ of the ligand, the substituent of the ligand may also be used. Since the planarity changes, the conjugate state of the ligand changes. Therefore, the emission color of the metal complex can be changed depending on the type of the substituent of the ligand. For example, the metal complex of formula (iii) is introduced t- butyl substituent X ₅ in the ligand, metal complex of formula (iv) is methyl substituent X ₅ ligand The group (Me) has been introduced. In addition, the introduction of a bulky group as a substituent has an effect of not only changing the emission color but also reducing the crystallinity of the metal complex when the metal complex is made thinner due to the bulkiness. Therefore, for example, by using a metal complex having a structure as shown in chemical formulas (iii) and (iv) as an organic compound material of an organic EL device, the uniformity and heat resistance of an organic layer formed by vapor deposition are increased, and It is possible to improve stability and extend the life.

The type of substituent introduced also affects the properties of the metal complex. The electronic state of the conjugated system of the ligand can be changed by changing the type of the substituent,
The emission wavelength can be adjusted. As the type of the substituent,
For example, there are an electron donating group and an electron withdrawing group. Examples of the electron donating substituent include an alkyl group, an amino group, and an alkoxy group. Examples of the electron-withdrawing substituent include a halogen group, a cyano group, a nitro group, and an alkyl group and an aryl group substituted with these groups. In the metal complex represented by the chemical formula (v), an alkoxy group is introduced as X _{3 and a} cyano group is introduced as X ₆ .
In the metal complex represented by the chemical formula (vi), a diethylamino group is introduced as X _{3 and a} cyano group is introduced as X ₆ .
When a desired electron donating group or electron withdrawing group is introduced as a substituent X _{1 to} X ₈ as in these chemical formulas (v) and (vi), a luminescent material having a desired emission wavelength of blue, green and red can be obtained. Can be obtained. Also, introducing an electron donating group or an electron withdrawing group as a substituent of the metal complex contributes to an increase in the luminescence intensity of the metal complex, and thus is effective in improving the luminescence intensity of the organic EL device.

Elements other than ligand substituents also affect the properties of the metal complex. For example, the central metal M of the complex corresponds. The center metal M is Zn, Al, Be, G as described above.
Although e and the like can be used, these metals affect the stability and emission color of the metal complex. Therefore, the center metal M can be selected according to the characteristics required as the organic material of the organic EL element.

Further, as another factor affecting the properties of the metal complex, the number l of ligands and L in chemical formula (2)
And the like. For example, the chemical formula (vi
As shown in i), the number of ligands may be three. Also,
When the compounds represented by the above-mentioned chemical formulas (7), (8) and (9) are used as auxiliary ligands in addition to the ligand represented by the chemical formula (1) and coordinated to the same central metal Also, the emission color, emission brightness, and the like can be adjusted. Chemical formula (vii
In the metal complex of i), 4-phenylphenol is used as the auxiliary ligand L.

As described above, the compound having a pyridylphenol skeleton represented by the chemical formula (1) is used as a ligand of a metal complex, and the substituents X _{1 to} X ₈ introduced by the ligand, the number of ligands l, By selecting the central metal M, the auxiliary ligand L, and the number m thereof, the desired emission wavelength, emission intensity, stability, and the like can be obtained. Therefore, various characteristics can be imparted to the metal complex while using the compound having the pyridylphenol skeleton represented by the chemical formula (1) as a common material.

The ligand represented by the chemical formula (1) of the metal complex according to the present embodiment is obtained by, for example, dehalogenating coupling of a halogenated aromatic oxide in which a hydroxyl group is protected and a halogenated pyridine derivative, It can be formed by removing the protecting group. However, it is not limited to such a manufacturing method.

[0036]

EXAMPLES Example 1 A synthesis example for synthesizing a compound of the formula (i) as a metal complex represented by the general formula (2), and an organic EL device using the compound (i) as an organic compound Will be described.

Example 1-1 Synthesis of Compound (i)

Embedded image (A) Synthesis of organic compound represented by chemical formula (14) To a suspension of 1.28 g of magnesium in 1 ml of THF (tetrahydrofuran) was added dropwise a solution of 10 g of orthomethoxybenzene in 15 ml of THF while stirring. After refluxing for 30 minutes, the solution was mixed with 7.5 g of 2-bromopyridine and 0.25 g of nickel catalyst in THF.
It was added dropwise to 15 ml of the solution at 0 ° C. After stirring at room temperature for 12 hours, 30 ml of water was added and the solvent was evaporated. The residue was extracted with chloroform, and the organic layer was washed with water, dried over sodium sulfate, and the solvent was removed.
g of the compound represented by the above chemical formula (14) was obtained.

(B) Synthesis of an organic compound represented by the chemical formula (15) 50 ml of the obtained methylene chloride solution of the above chemical formula (14) (8.84 g) was prepared, and this solution was cooled to -78 ° C. To this, a 1 N solution of boron tribromide in methylene chloride was added dropwise with stirring. The mixture was slowly returned to room temperature and stirred for 12 hours. 60 ml of water was slowly added to the reaction mixture, and the aqueous layer was extracted twice with 100 ml of methylene chloride. After drying the organic layer over sodium sulfate, the solvent was removed and 3.3.
5 g of the compound represented by the chemical formula (15) was obtained.

(C) Synthesis of the organic compound represented by the chemical formula (i) 294 mg of the compound of the above formula (15) was dissolved in 15 g of methanol, and a solution of 175 mg of zinc acetate in methanol (1 g) [175 mg of zinc acetate and 1 g of methanol
And a mixture of the above). Triethylamine 23
1 g of a 1 mg methanol solution was added dropwise, and the mixture was stirred at room temperature overnight. After adding 30 ml of chloroform to make a homogeneous solution, this was dropped into 300 ml of hexane. After filtration, washing with hexane and water, and drying under vacuum, the chemical formula (i) was obtained.

The compound represented by the chemical formula (i) was obtained by DSC
(Differential thermal analysis) As a result of measurement, it was found that neither the glass transition temperature Tg nor the melting point of this compound was observed below 300 ° C., indicating that this compound had a glass transition temperature and melting point higher than 300 ° C.

Example 1-2 Organic EL Device Using Compound (i) An organic EL device having a structure as shown in FIG. 1 was produced by using the metal complex compound represented by the chemical formula (i). First, the ITO electrode 12 was formed on the glass substrate 10 (however, a commercially available glass substrate on which ITO was previously formed may be used). On the ITO electrode 12, TPD represented by the above chemical formula (6) is vacuum-deposited as a hole transport layer by 60 nm, and the compound (i) is deposited thereon as a light-emitting layer by 60 nm,
Organic compound layer 14 was obtained. Finally, M is used as the metal electrode 16.
g / Ag (9: 1) was deposited to obtain an organic EL device.

When the organic EL device was driven at room temperature under a nitrogen gas atmosphere under a current injection condition of 10 mA / cm ² , blue light was emitted at a light emission luminance of 145 cd / cm ² . The half life of luminance of this element was 1500 hours.

Example 2 A synthesis example for synthesizing a compound of the formula (ii) as a metal complex represented by the general formula (2) and an organic EL device using the compound (ii) as an organic compound explain.

Example 2-1 Synthesis of Compound (ii)

Embedded image (A) Synthesis of organic compound represented by chemical formula (16) 277 g of aluminum chloride and 27.7 g of sodium chloride were mixed, heated to 150 ° C. and dissolved. Chroman-4-one was added over 10 minutes and heated at 200 ° C. for 30 minutes. After cooling, slowly add concentrated hydrochloric acid 150m
A mixture of 1 and ice was added. 3 with 200 ml of chloroform
It was extracted once, dried over sodium sulfate, evaporated and recrystallized from methanol to obtain 26.67 g of the compound represented by the chemical formula (16).

(B) Synthesis of the organic compound represented by the chemical formula (17) 25 g of the obtained compound of the chemical formula (16), THF45m
13 ml of dimethyl sulfuric acid was added over 5 minutes while stirring at 60 ° C. with 61 ml of a 10 wt% aqueous sodium hydroxide solution. The operation of adding 31 ml of an aqueous sodium hydroxide solution and then adding 7 ml of dimethyl sulfuric acid was repeated three times, followed by heating at 90 ° C. for 15 minutes. After adjusting the pH to 10 with an aqueous sodium hydroxide solution, the mixture was extracted three times with 100 ml of chloroform. After drying over sodium sulphate, evaporation and subsequent recrystallization from toluene. This was vacuum dried to obtain 20.09 g of the compound represented by the chemical formula (17).

(C) Synthesis of the organic compound represented by the chemical formula (18) 2.0 g of the obtained compound of the chemical formula (17), 0.88 g of 3-aminoacrolein and 26 mg of ammonium acetate
And heated at 120 ° C. for 20.5 hours. After adding 1 N hydrochloric acid to adjust the pH to 1, the aqueous layer was washed with 50 ml of chloroform.
Extracted twice with ml. Adjust the pH of the aqueous layer with potassium carbonate to 10
And extracted twice with 50 ml of chloroform. The organic layer was dried over sodium sulfate and dried under vacuum to obtain 2.6 g of crude product. PTLC (Preparative Thin Layer C
The product was isolated by preparative TLC to obtain 0.43 g of the compound represented by the formula (18).

(D) Synthesis of an organic compound represented by the chemical formula (19) 3.14 g of a solution of the compound represented by the chemical formula (18) in 30 ml of methylene chloride was cooled to -78 ° C., and 1.0M boron tribromide in methylene chloride was cooled. 15 ml of the solution was added dropwise. The mixture was slowly returned to room temperature and left for 12 hours. After slowly adding 50 ml of water, the mixture was extracted twice with 50 ml of chloroform.
The organic layer was evaporated and isolated by silica gel column chromatography to obtain 0.96 g of the compound represented by the formula (19).

(E) Synthesis of organic compound represented by chemical formula (ii) 294 mg of the compound represented by chemical formula (19) was dissolved in 15 g of methanol, and a solution of 175 mg of zinc acetate in 1 g of methanol [175 mg of zinc acetate and 1 g of methanol
Was added dropwise, and the mixture was stirred overnight at room temperature.
After adding 30 ml of chloroform to make a homogeneous solution, it was dropped into 300 ml of hexane. This is filtered, hexane,
After each washing with water, vacuum drying gave chemical formula (ii).

As a result of DSC measurement of the compound represented by the chemical formula (ii), neither the glass transition temperature Tg nor the melting point of the compound was observed below 300 ° C.
It has been found to have a higher glass transition temperature and melting point.

Example 2-2 Organic EL Device Using Compound (ii) An organic EL device having a structure as shown in FIG. 1 was produced using the metal complex compound represented by the above chemical formula (ii). The device was manufactured under the same conditions except that the compound of the chemical formula (i) used in Example 1-2 described above was changed to the compound (ii) according to the present example.

When the obtained organic EL device was driven at room temperature under a nitrogen gas atmosphere under a current injection condition of 10 mA / cm ² , green light was emitted at a light emission luminance of 155 cd / cm ² . The half life of luminance of this device is 1700.
It was time.

Example 3 A synthesis example for synthesizing a compound of the formula (iv) as a metal complex represented by the general formula (2) and an organic EL device using the compound (iv) as an organic compound explain.

Example 3-1 Synthesis of Compound (iv)

Embedded image (A) Synthesis of organic compound represented by chemical formula (20) 1. A suspension of 1.25 g of magnesium in 1 ml of THF was
Under stirring, 10 g of orthomethoxybromobenzene
ml THF solution was added dropwise. After refluxing for 30 minutes, this solution was added dropwise at 0 ° C. to 15 ml of a THF solution containing 8 g of 2-bromo-3-methylpyridine and 0.25 g of a nickel catalyst. After stirring at room temperature for 12 hours, 30 ml of water was added and the solvent was evaporated. The residue was extracted with chloroform, the organic layer was washed with water, dried over sodium sulfate, and the solvent was removed to obtain 8.3 g of 2- (2-methoxyphenyl) -3-methylpyridine represented by the chemical formula (20). Was.

(B) Synthesis of organic compound represented by chemical formula (21) A solution of 8.3 g of the compound represented by chemical formula (20) in 50 ml of methylene chloride was cooled to -78 ° C. To this, a 1 N solution of boron tribromide in methylene chloride was added dropwise with stirring.
The mixture was slowly returned to room temperature and stirred for 12 hours. 60 ml of water
Was slowly added to the reaction mixture, and the aqueous layer was
Extracted twice with 00 ml. After the organic layer was dried over sodium sulfate, the solvent was removed to obtain 4.1 g of 2- (2-hydroxyphenyl) -3-methylpyridine represented by the chemical formula (21).

(C) Synthesis of organic compound represented by chemical formula (iv) 305 mg of the compound represented by chemical formula (21) was dissolved in 15 g of methanol, and a solution of 178 mg of zinc acetate in 1 g of methanol [178 mg of zinc acetate and 1 g of methanol were added. Was added dropwise, and the mixture was stirred at room temperature overnight. After adding 30 ml of chloroform to make a homogeneous solution, it was dropped into 300 ml of hexane. This was filtered, washed with hexane and water, and dried under vacuum to obtain a compound represented by the chemical formula (iv).

As a result of DSC measurement of the compound represented by the chemical formula (iv), neither the glass transition temperature Tg nor the melting point of the compound was observed below 300 ° C.
It has been found to have a higher glass transition temperature and melting point.

Example 3-2 Organic EL Device Using Compound (iv) An organic EL device having a structure as shown in FIG. 1 was produced using the metal complex compound represented by the above chemical formula (iv). The device was manufactured under the same conditions except that the compound of the chemical formula (i) used in Example 1-2 described above was changed to the compound (iv) according to this example.

When the obtained organic EL device was driven at room temperature under a nitrogen gas atmosphere under a current injection condition of 10 mA / cm ² , blue-green light was emitted at an emission luminance of 205 cd / cm ² . The half life of luminance of this element is 180.
It was 0 hours.

Example 4 A synthesis example for synthesizing a compound of the formula (viii) as a metal complex represented by the general formula (2) and an organic EL device using the compound (viii) as an organic compound explain.

Example 4-1: Synthesis of compound (viii)

Embedded image 300 mg of the compound (15) was dissolved in 7 ml of a THF solution, and 0.87 ml of a 0.98 M trimethylaluminum hexane solution was added dropwise. To this, 145 mg of 4-phenylphenol represented by the chemical formula (22) was added, followed by stirring, evaporation, washing with water, and vacuum drying to obtain a compound represented by the chemical formula (viii).

The compound represented by the chemical formula (viii) was obtained by DSC
As a result of the measurement, below 300 ° C., neither the glass transition temperature Tg nor the melting point of this compound was observed.
It has been found to have a glass transition temperature and melting point higher than ° C.

Example 4-2 Organic EL Device Using Compound (viii) Using a metal complex compound represented by the above chemical formula (viii), FIG.
An organic EL device having the structure shown in FIG. The element is
The compound of formula (i) used in Example 1-2 described above was changed to the compound (viii) according to this example, and the others were prepared under the same conditions.

When the obtained organic EL device was driven at room temperature under a nitrogen gas atmosphere under a current injection condition of 10 mA / cm ² , green light was emitted with an emission luminance of 180 cd / cm ² . The half life of luminance of this device was 800 hours.

Comparative Example For comparison with the organic EL devices manufactured in Examples 1 to 4, Alq ₃ represented by the chemical formula (3) was used as a light emitting material of an organic layer instead of the metal complex of each Example. The organic EL was used under the same conditions as in each example except for the use.
An element was manufactured.

When the obtained organic EL device was driven at room temperature under a nitrogen gas atmosphere under a current injection condition of 10 mA / cm ² , green light was emitted with a light emission luminance of 150 cd / cm ² . The half life of luminance of this element is 1000.
It was time.

[Comparative study]

[Table 1] The above Table 1 shows the organic E of each of Examples 1 to 4 and Comparative Example described above.
It is a summary of each characteristic of the L element. As can be seen from the above description and the comparison of Table 1, in the organic EL device using the metal complex compound according to the present invention, blue, green, bluish green, etc. are obtained by each metal complex having a common skeleton ligand. Different emission colors are obtained. Further, a sufficient light emission luminance similar to or very high as that of Alq ₃ is obtained. As for the luminance half life, the formula (viii), but are comparable with Alq _3, the element using the other metal complexes, Alq ₃
Is significantly higher than the device using. Further, as for the glass transition temperature, all of the compounds according to the examples of the present invention have a glass transition temperature Tg of more than 300 ° C., which means that the compounds are extremely excellent in heat resistance.

In the above examples, four types of compounds exhibiting blue, blue-green, and green emission have been described as examples. However, other metal complexes represented by the general formula (2) may also be used. By selecting a ligand substituent, a central metal, an auxiliary ligand, and the like, a compound that emits blue, green, blue-green, or even red light can be obtained. For example, the compounds represented by the chemical formulas (v) and (vi) are considered to emit red to green light.

[0068]

As described above, in the present invention, the chemical formula (2) is used as the organic compound material of the organic EL device.
Is used. This compound, X ₁ ~ ligands basic skeleton represented by the chemical formula (1)
Configuration of the substituents to be introduced as X _8, by selecting the type, the emission wavelength can be easily adjusted, and can also be improved, such as luminous efficiency and heat resistance. Furthermore, the emission wavelength, heat resistance, and emission efficiency can be easily adjusted by adjusting the type of the central metal M, the existence and the type of the auxiliary ligand L, and the like.

Therefore, when such a metal complex is used as an organic compound material of an organic EL device, an organic EL device having a long life, high efficiency, and showing various luminescent colors can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an organic EL element according to an embodiment.

[Explanation of symbols]

Reference Signs List 10 transparent substrate, 12 first electrode (ITO electrode, anode), 14 organic compound layer, 16 second electrode (metal electrode, cathode).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07F 3/00 C07F 3/00 D 3/06 3/06 5/06 5/06 E 7/30 7 / 30F (72) Inventor Hisato Takeuchi 41-cho, Chuchu-Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central Research Laboratory Co., Ltd. (72) Inventor Osamu Watanabe 41-Cho, Yakumichi, Nagakute-machi, Aichi-gun (1) Toyota Central Research Institute, Inc. (72) Inventor Tomohiko Mori 41-cho, Yokomichi, Oku-cho, Nagakute-cho, Aichi-gun, Aichi Prefecture Ground 1 Inside Toyota Central Research Institute, Inc. (72) Inventor Shizutoshi Tokito Nagakute, Aichi County, Aichi Prefecture No. 41, 41, Yokomichi, Chumachi, Chuo-cho F-term in Toyota Central R & D Laboratories Co., Ltd. 3K007 AB00 AB02 AB03 AB04 AB14 CA00 CA01 CA02 CB01 DA00 DB03 EB00 FA01 FA03 4C034 CH02 4C055 AA01 BA02 BA08 BA16 BA27 BB0 1 BB02 BB13 CA01 CA02 CA05 CA06 DA01 DA59 EA01 4H048 AA03 AB92 VA20 VA30 VA32 VA60 VA66 VA80 VB10 4H049 VN02 VP01 VQ59 VQ60 VQ89 VQ93 VR42 VR52 VS59 VS60 VU29

Claims (2)

[Claims] 1. An organic electroluminescent device comprising one or more organic compound layers between electrodes, wherein at least one of the organic compound layers has the following chemical formula (1): An organic electroluminescent device comprising a metal complex compound having a compound of a basic skeleton represented by the formula (1) as a ligand. 2. An organic electroluminescent device comprising one or more organic compound layers between electrodes, wherein at least one of the organic compound layers has the following chemical formula (2). A metal complex compound comprising a central metal represented by M, one or more l ligands of a pyridylphenol skeleton, and zero or more m auxiliary ligands represented by L An organic electroluminescent device comprising: