JP4438394B2 - Organometallic complex and organic electroluminescence device using the same - Google Patents

Description

  The present invention relates to an organometallic complex useful as a novel phosphorescent dye. Specifically, the present invention relates to an organic light emitting material used for a dye laser, a lighting apparatus, a thin film type organic light emitting device, an electrophotographic photosensitive member, and the like, and an organic electroluminescent element using the organic light emitting material.

Until now, many organic dyes have been used in organic electroluminescent devices, but for applications such as flat panel displays, light sources such as fluorescent lamps and marker lamps, and near-infrared light emitting materials, There is a need to further improve the light emission efficiency of the device, and development of a new light emitting material is required.
In recent years, as one of attempts to increase the light emission efficiency of devices, the use of phosphorescent dyes utilizing light emission from triplet excited states, that is, phosphorescence, has attracted attention. When phosphorescence is used, the efficiency can be increased up to about 4 times as compared with the conventional light emission (fluorescence) from the singlet excited state. Among them, since the organometallic complex has a relatively short phosphorescence lifetime, the triplet-triplet annihilation can be suppressed, so that improvement in luminous efficiency can be expected.

Many organometallic complexes have been studied so far, and a complex having green to red phosphorescence emission has been reported to achieve high-efficiency emission exceeding that of a fluorescent dye (Non-Patent Documents 1 and 2). 3 and 4).
On the other hand, there are few reports on blue light emission and it is still under development.
For example, Patent Document 1 describes the following compounds, but none of them has a long maximum emission wavelength and blue emission with high color purity cannot be realized.

（各化合物の下に記載したものは、最大発光波長である。）
特許文献１など、これまでに提案されている青色燐光発光色素に関する報告例から、本発明者らは、電子吸引基を１個しか有さない有機金属錯体では、色純度の高い青色発光を達成することは困難であり、少なくとも２個以上の電子吸引基を発光配位子に有する必要があると考えた。

(What is listed under each compound is the maximum emission wavelength.)
From reported examples of blue phosphorescent dyes proposed so far, such as Patent Document 1, the present inventors have achieved blue light emission with high color purity in an organometallic complex having only one electron-withdrawing group. It was difficult to do so, and it was considered necessary to have at least two electron-withdrawing groups in the light-emitting ligand.

  As an organometallic complex having two or more electron-withdrawing groups, for example, Patent Document 2 discloses the following complex. This has been introduced as a phosphorescent dye that exhibits blue light emission with relatively high efficiency.

また、非特許文献５には下記錯体（Ｋ−３）が記載され、特許文献３には下記錯体（Ｋ−９）および（Ｋ−２４）が記載されており、いずれも青色発光を示すと記載されている。

Non-Patent Document 5 describes the following complex (K-3), and Patent Document 3 describes the following complexes (K-9) and (K-24), both of which emit blue light. Are listed.

However, in both of these, since the fluorine atom adjacent to the pyridyl group on the phenyl group in the ligand is partly eliminated during complex formation, the compound obtained by synthesis becomes a mixture, and the resulting dye It is considered to have an adverse effect on the color purity of.
As an example in which two or more fluorine atoms are substituted at different positions of the ligand in the same organometallic complex, for example, Patent Document 3 includes the following complexes (K-9) and (K-16). Are listed.

The maximum emission wavelength of (K-9) is 485 nm from the example of Patent Document 3. On the other hand, the maximum emission wavelength of (K-16) was 499 nm according to the inventors' further examination.
That is, in the case of such an organometallic complex, it has been found that the emission wavelength is increased by introducing a fluorine atom at the p-position with respect to the coordination position to the iridium in the phenyl group in the ligand. did. Therefore, when two or more fluorine atoms are introduced, the emission wavelength becomes longer depending on the bonding position, and it can be said that blue phosphorescence is more difficult to obtain.
WO 02/02714 WO 02/15645 JP 2002-117978 A Appl.Phys.Lett., 1999,75,5 J. Am. Chem. Soc., 2001, 123,4304 Inorg.Chem., 2001,40,1704 J.Am.Chem.Soc., 2002,124,9945 J. Am. Chem. Soc., 2003, 125, 7377

  An object of the present invention is to provide a compound exhibiting blue phosphorescence with high color purity, high electrical redox durability and electrochemical stability, and an organic electroluminescent device using this compound as a light emitting layer material. There is.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that a blue color having a high color purity can be obtained by specifying the introduction position of an electron-withdrawing group in a ligand of an organometallic complex having a specific central metal. It has been found that the stability of the compound is ensured by realizing light emission and not having a hydrogen atom, a halogen atom, a cyano group, or other group that is easily eliminated or hydrolyzed at another specific position. The present invention has been completed based on these findings.

  That is, the present invention relates to an organometallic complex represented by the following general formula (i), a luminescent material containing the organometallic complex, an organic electroluminescent element material, and an organic electroluminescent element having a layer containing the organometallic complex Exist.

Wherein X and Y are each independently a fluorine atom, an alkyl group having 1 to 15 carbon atoms substituted with at least one fluorine atom, or a carbon atom having 1 to 1 carbon atoms substituted with at least one fluorine atom.
5 alkoxy groups, C2-C30 alkoxyalkyl groups substituted with at least one fluorine atom, C2-C30 alkoxyalkoxy groups substituted with at least one fluorine atom, at least one fluorine 1 or 2 alkylamino groups having 1 or 2 alkyl chains having 1 to 10 carbon atoms substituted with atoms, or 1 or 2 aromatic hydrocarbon groups having 6 to 18 carbon atoms substituted with at least one fluorine atom An arylamino group, an acylamino group having 1 or 2 acyl groups having 2 to 30 carbon atoms substituted with at least one fluorine atom, and an alkylthio group having 1 to 15 carbon atoms substituted with at least one fluorine atom group, at least one aromatic hydrocarbon group having 6 to 18 carbon atoms which is substituted with a fluorine atom, -R ¹⁰¹ C
OR ¹⁰² , —OR ¹⁰³ COR ¹⁰⁴ , —COR ¹⁰⁵ , and —OCOR ¹⁰⁶ (where R ^{101 to} R ¹⁰⁶ each independently represents an alkyl group having 1 to 15 carbon atoms substituted with at least one fluorine atom, or Represents an alkylene group.) Represents an electron-withdrawing group selected from the group consisting of: X and Y which are the electron-withdrawing groups may be bonded to each other to form a 5- or 6-membered ring substituted with at least one fluorine atom .
Z has a hydroxyl group, a halogen atom or an alkyl group having 1 to 4 carbon atoms as a substituent, and an alkyl group having 1 to 15 carbon atoms, a halogen atom or an alkyl group having 1 to 4 carbon atoms as a substituent. An optionally substituted alkoxyl group having 1 to 10 carbon atoms, a halogen atom or an alkyl group having 1 to 4 carbon atoms, which may have a substituent, and an aromatic hydrocarbon group having 6 to 18 carbon atoms , and halogen Aromatics consisting of 5- or 6-membered monocyclic or 2-4 condensed rings containing oxygen atoms, nitrogen atoms or sulfur atoms which may have an atom or an alkyl group having 1 to 4 carbon atoms as a substituent It represents a substituent selected from the group consisting of heterocyclic groups.
M represents Re, Ru, Co, Ir, Pt, or Au, and L represents a monovalent bidentate ligand that forms a 5-membered ring or a 6-membered ring with the central metal M at the time of complex formation. n represents the valence of the metal M and is an integer of 1 to 3.
Ring A is a 5- or 6-membered ring optionally having a substituent selected from the group consisting of a fluorine atom, an acetyl group, an alkyl group having 1 to 5 carbon atoms , and an alkoxyl group having 1 to 5 carbon atoms. Represents an aromatic heterocycle.
Z and ring A may be bonded to each other to form a 5- or 6-membered ring which may contain an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom.
X ¹ represents a carbon atom or a nitrogen atom.
In the formula

Represents a single bond or a double bond. )
Such an organometallic complex is suitable for obtaining blue phosphorescence having high color purity, but is preferably one having a maximum emission wavelength of 480 nm or less.
The organometallic complex of the present invention preferably has a molecular weight of 500 or more and 5000 or less.
As the organic electroluminescent element of the present invention, a layer containing the organometallic complex of the present invention is preferably a light emitting layer. In particular, the light emitting layer may contain a host material having hole injection / transport properties or electron injection / transport properties, and the host material is doped with the organometallic complex of the present invention. More preferable.
Moreover, as an organic electroluminescent element of this invention, what has a hole-blocking layer which contact | connects the cathode side interface of a light emitting layer is preferable.

  According to the present invention, it is possible to improve the chemical and electrical stability, improve the color purity, and adjust the acid value reduction potential of an organometallic complex that exhibits blue phosphorescence. By using such an organometallic complex, an organic electroluminescent device having high color purity and high luminous efficiency can be obtained.

Hereinafter, the present invention will be described in detail.
The organometallic complex according to the present invention will be described. The organometallic complex of the present invention has a ligand formed by bonding a phenyl group and a heteroaryl group, an electron-withdrawing group is bonded to a specific part of the phenyl group, and another specific part includes It has a feature that it does not have a hydrogen atom, a halogen atom, a cyano group, or the like, and a group that can be easily removed and hydrolyzed. Specifically, as shown in the following general formula (i), X and Y have an electron-withdrawing group, and Z has a group other than a hydrogen atom, a halogen atom and a cyano group.

(Wherein X and Y each independently represent an electron-withdrawing group, or X and Y may be bonded to each other to form an optionally substituted ring.
Z represents any substituent other than a halogen atom and a cyano group.
M represents Re, Ru, Co, Ir, Pt or Au, and L represents a monovalent bidentate ligand. n represents the valence of the metal M and is an integer of 1 to 3. Ring A represents an aromatic ring which is a 5- or 6-membered ring which may have a substituent.
In the formula

Represents a single bond or a double bond. )
In general formula (i), X and Y each independently represent an electron-withdrawing group. In the present invention, the “electron withdrawing group” is a general term for the following groups.
[Electron withdrawing group]
The following [α group], [β group] substituted with at least one group selected from [α group], and optionally substituted with at least one group selected from [α group] [ γ group].
[Α group] fluorine atom, chlorine atom, carbonyl group, carboxyl group,

[Β group]
An alkyl group having 1 to 15 carbon atoms,
An alkoxy group having 1 to 15 carbon atoms,
An alkoxyalkyl group having 2 to 30 carbon atoms,
An alkoxyalkoxy group having 2 to 30 carbon atoms,
An alkylamino group having one or two alkyl chains having 1 to 10 carbon atoms,
An arylamino group having 1 or 2 aromatic hydrocarbon groups having 6 to 18 carbon atoms,
An acylamino group having 1 or 2 acyl groups having 2 to 30 carbon atoms,
An alkylthio group having 1 to 15 carbon atoms,
An aromatic hydrocarbon group having 6 to 18 carbon atoms,
-R ¹⁰¹ COR ¹⁰² , -OR ¹⁰³ COR ¹⁰⁴ , -COR ¹⁰⁵ , -OCOR ¹⁰⁶
(However, R < ¹⁰¹ > -R < ¹⁰⁶ > represents a C1-C15 alkyl group or alkylene group each independently.)

[Γ group]
An alkylboryl group having 1 or 2 alkyl chains having 1 to 15 carbon atoms,
An arylboryl group having 1 or 2 aromatic hydrocarbon groups having 6 to 18 carbon atoms,
An alkylsulfonyl group having 1 or 2 alkyl chains having 1 to 15 carbon atoms,
The arylsulfonyl group having one or two aromatic hydrocarbon groups having 6 to 18 carbon atoms, specific examples of the electron-withdrawing group include the following groups, but are not limited thereto.

（上記構造中、Ｍｅはメチル基、Ｂｕはブチル基を表す。）
なお、合成のしやすさの観点からは、ＸとＹは同一の基であることが好ましく、また色純度の調整の観点からは、ＸとＹは異なる基であることが好ましい。

(In the above structure, Me represents a methyl group and Bu represents a butyl group.)
From the viewpoint of ease of synthesis, X and Y are preferably the same group, and from the viewpoint of adjusting color purity, X and Y are preferably different groups.

  X and Y may be bonded to each other to form a ring that may have a substituent. When forming a ring, examples of the partial structure formed by bonding X and Y include the following structures.

(In the above structure, Me represents a methyl group.)
X and Y are each preferably an electron-withdrawing group from the viewpoint of color purity, and from the viewpoint of suppressing concentration quenching, X and Y may be bonded to each other to form an optionally substituted ring. The case where it forms is preferable.

In the organometallic complex represented by the general formula (i), X and Y are more preferably a fluorine atom and a β group substituent having a fluorine atom from the viewpoint of sublimation,
A fluorine atom, and an alkyl group, an alkoxyl group, and an aryl group having a fluorine atom are particularly preferable.
In the general formula (i), Z represents a group that is neither a halogen atom nor a cyano group.

Among them, Z is preferably
Hydroxyl group,
An alkyl group which may have a substituent (for example, an alkyl group having 1 to 15 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group),
An alkoxyl group which may have a substituent (for example, an alkoxy group having 1 to 10 carbon atoms such as a methoxy group or an ethoxy group),
An aromatic hydrocarbon group which may have a substituent (for example, an aromatic hydrocarbon group having 6 to 18 carbon atoms such as a phenyl group, a naphthyl group, a phenanthryl group),
An aromatic heterocyclic group which may have a substituent (for example, an aromatic heterocyclic group consisting of a 5- or 6-membered monocyclic ring or a 2-4 condensed ring such as a xylyl group, a pyridyl group, a pyrazole group or an imidazole group) Ring group)
Etc.

Examples of the substituent that the alkyl group, alkoxy group, aromatic hydrocarbon group, and aromatic heterocyclic group may have include a halogen atom and an alkyl group having about 1 to 4 carbon atoms.
From the viewpoint of synthesis, Z is particularly preferably an alkyl group that may have a substituent, a hydroxyl group, an alkoxyl group that may have a substituent, a phenyl group that may have a substituent, and a pyridyl group. is there.

  Ring A represents a 5- or 6-membered aromatic heterocyclic ring which may have a substituent. Preferably, the ring shown below is mentioned, but it is not limited to these.

Among these, a pyridine ring is most preferable in that high luminance emission can be expected.
Examples of the substituent that ring A may have include, for example, a fluorine atom; an acetyl group having 1 to 5 carbon atoms; an alkyl group having 1 to 5 carbon atoms such as a methyl group and an ethyl group; and a carbon number such as a methoxy group and an ethoxy group. 1-5 alkoxyl groups; C3-C8 aromatic heterocyclic groups such as pyridyl groups and pyrazyl groups; C6-C10 aromatic hydrocarbon groups such as phenyl groups and naphthyl groups. Among these, a fluorine atom, an acetyl group, an alkyl group, and an alkoxyl group are preferable.
L represents a monovalent bidentate ligand and is preferably a relatively soft base. Preferably, it represents a bidentate ligand that forms a 5-membered ring or a 6-membered ring with the central metal M during complex formation. Specific examples include the following bidentate ligands, but are not limited thereto.

  When a bidentate ligand in which two atoms forming a coordination bond with the central metal M both form part of an aromatic ring is used as the ligand L, the ligand L is There is a possibility that the characteristics of the light-emitting ligand, which is a characteristic part of the present invention, are not sufficiently exhibited due to strong participation in light emission of the organometallic complex. As a result, since it may be difficult to obtain blue light emission, as represented by the above example, as the ligand L, among the two atoms that form a coordination bond with the central metal M, A ligand in which at least one does not constitute a part of the aromatic ring is preferable.

In the general formula (i), M represents the central metal of the organometallic complex and represents Re, Ru, Co, Ir, Pt, or Au. From the viewpoint of efficiency, Ir or Pt is preferable.
n represents the valence of the metal M and is an integer of 1 to 3. From the viewpoint of the stability of the complex,
More preferably, it is 2 or 3.
The molecular weight of the compound represented by the general formula (i) is usually about 5000 or less, preferably about 2500 or less, and more preferably about 1500 or less. The lower limit of the molecular weight is usually about 1200, preferably about 1000, and more preferably about 800. If the molecular weight is too large, the sublimation property is lowered, and for example, it tends to be difficult to form a thin film by vapor deposition, which may cause a problem when used for a layer constituting an organic electroluminescent element as described later. On the other hand, if the molecular weight is too small, for example, the sublimation temperature becomes too low, so that it may be difficult to form a thin film by vapor deposition.

Note that when the thin film is formed by a wet film formation method such as spin coating, the molecular weight range is not necessarily satisfied.
Specific examples of the organometallic complex represented by the general formula (i) are shown below, but the present invention is not limited thereto. In the figure, Me represents a methyl group.
Structural formulas (I) to (IV) in the following table correspond to the following.

本発明の有機金属錯体は、公知の手法で合成することができる。その一例を以下に説明する。
まず、以下に配位子の一般的合成法を示す。

The organometallic complex of the present invention can be synthesized by a known method. One example will be described below.
First, the general synthesis method of a ligand is shown below.

The aryl halide and the corresponding Grignard reagent, aryl zinc halide, aryl tin compound, and aryl boronic acid are reacted in an organic solvent using a metal catalyst.
As the metal catalyst, tetrakistriphenylphosphine palladium (0), dichlorobistriphenylphosphine palladium (II), or the like is used.
Examples of the organic solvent include benzene, toluene, tetrahydrofuran, dimethylformamide, dimethoxyethane and the like.
The reaction temperature is 0 ° C to 200 ° C, preferably 20 ° C to 120 ° C.

In order to obtain the organometallic complex of the present invention using the obtained ligand, Bull. Chem. Soc. Jpn., 1974, 47, 767, Inorg. Chem., 2001, 40, 1704, J. Am. Chem. Reaction may be carried out according to the method described in Soc., 2003, 125, 7377, etc.
Such an organometallic complex of the present invention exhibits blue light emission with high color purity and is excellent in various points such as luminous efficiency and durability. As a luminescent material, coloring of various materials such as resins, dyes, and inks is possible. , And laser dyes, organic electroluminescent element dyes, electrophotographic photoreceptor raw materials, near-infrared light emitting organometallic complexes, and the like.

Further, by using the organometallic complex of the present invention, an excellent organic electroluminescence device having high luminous efficiency and high fastness and suitable for a blue light emitting device can be obtained, and therefore, it is suitable as an organic electroluminescence device material.
The organic electroluminescent element of the present invention is characterized in that an anode, a light emitting layer, and a cathode are sequentially laminated on a substrate, and has a layer containing an organometallic complex represented by the general formula (i). . The organometallic complex represented by the general formula (i) is preferably contained in the light-emitting layer, and is particularly doped with a host material having hole injection / transport properties or electron injection / transport properties in the light-emitting layer. It is preferable to contain.

In addition, in the light emitting layer of the organic electroluminescent element of this invention, 1 type of the organometallic complex of this invention may be contained independently, and 2 or more types may be contained.
Hereinafter, the host material suitable for the present invention will be described.
The host material preferably has an excited triplet level in an energy state higher than the excited triplet level of the organometallic complex represented by the general formula (i) included in the light emitting layer. Moreover, it is necessary to be a compound which gives a stable thin film shape, has a high glass transition temperature (Tg), and can efficiently transport holes and / or electrons.

Furthermore, the compound is required to be a compound that is electrochemically and chemically stable, and does not easily generate impurities during production or use, which become traps or quench light emission.
Examples of the host material satisfying these conditions include a compound represented by the following general formula (I) or (II) or a compound having a group represented by the following general formula (III).

(In the formula (I), the carbazolyl group and the phenylene group may have an arbitrary substituent. Z ¹ represents a direct bond or a divalent linking group.)

(In the formula (II), M ⁰ represents a metal selected from Group 1, 2, 3, 12, or 13 of the periodic table, k represents the valence of the metal, and L ⁰ represents an arbitrary value. Represents a substituent, and j represents the number of the substituent L ⁰ and is 0 or 1. X ² represents a carbon atom or a nitrogen atom, ring A ⁰ represents a nitrogen-containing heterocyclic ring, and has a substituent. Ring B ⁰ represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring, which may have a substituent.

((III) wherein independently each R ⁵¹ to R ^54, represent a hydrogen atom or an arbitrary substituent, R ⁵¹
And R ⁵² , R ⁵³ and R ⁵⁴ may be bonded to each other to form a ring. X ³ represents an oxygen atom or a sulfur atom. )
The compound having an N-phenylcarbazole skeleton represented by the general formula (I) is preferably a compound represented by the following general formula (I-1).

(In formula (I-1), R ^{1 to} R ¹⁶ are each independently a hydrogen atom, halogen atom, alkyl group, aralkyl group, alkenyl group, cyano group, amino group, acyl group, alkoxycarbonyl group, carboxyl group, An alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, R ¹ and R ² , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁷ and R ⁸ , R ⁹ and R ¹⁰ , R ¹¹ and R ¹² , R ¹³ and R ¹⁴ , R ¹⁵ and R ¹⁶ are bonded to each other to form a ring. Z ¹
Represents a direct bond or a divalent linking group. (I-1) As R ^{1 to} R ¹⁶ in the formula, specifically, a hydrogen atom; a halogen atom such as a chlorine atom or a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group; An aralkyl group such as a group; an alkenyl group having 2 to 6 carbon atoms such as a vinyl group; a cyano group; an amino group; an acyl group; an alkoxycarbonyl group having 2 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; C1-C6 alkoxy groups such as methoxy group and ethoxy group; alkylamino groups such as diethylamino group and diisopropylamino group; aralkylamino groups such as dibenzylamino group and diphenethylamino group; haloalkyl such as trifluoromethyl group Group; hydroxyl group; aryloxy group such as phenoxy group and benzyloxy group; phenyl group optionally having substituent; Aromatic hydrocarbon groups such as methyl group, which may have a substituent group thienyl group, an aromatic heterocyclic group such as pyridyl group.

  Examples of the substituent that the aromatic hydrocarbon group and aromatic heterocyclic group may have include a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; and a carbon number such as a vinyl group. An alkenyl group having 2 to 6 carbon atoms; an alkoxycarbonyl group having 2 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; a phenoxy group and a benzyloxy group Aryloxy group; alkylamino group such as dimethylamino group and diethylamino group; acyl group such as acetyl group; haloalkyl group such as trifluoromethyl group; cyano group and the like.

In addition, all the alkyl chain parts contained in each of the above-described substituents may be linear or branched. The same applies to the following examples of substituents.
R ¹ and R ² , R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁷ and R ⁸ , R ⁹ and R ¹⁰ , R ¹¹ and R ¹² , R ¹³ and R ¹⁴ , R ¹⁵ and R ¹⁶ are Each of the adjacent substituents may be bonded to each other to form a 5- to 7-membered ring such as a benzene ring or a cyclohexane ring.

Particularly preferred as R ¹ to R ¹⁶ are a hydrogen atom, an alkyl group, or a cyano group.
Z ¹ in the general formula (I) or (I-1) is preferably a direct bond, an oxygen atom,
A sulfur atom, a linking group shown below,

Examples thereof include a divalent aromatic hydrocarbon group or aromatic heterocyclic group which may have a substituent, or any of the following linking groups.

(The benzene ring moiety in the above structure may have any substituent, and Ar ^{1 to} Ar ⁶ may have an aromatic hydrocarbon group or aromatic heterocyclic group which may have a substituent. Or a group represented by the following general formula (I-2).

In addition, the carbazolyl group and phenylene group in Formula (I-2) may have an arbitrary substituent. )
Of the preferred linking groups represented by Z ^{1 in} the general formula (I) or (I-1), the aromatic hydrocarbon group may be a 5- to 6-membered single ring such as a phenylene group, a naphthylene group, an anthranyl group, or a naphthacene group. Examples of the aromatic heterocyclic group include 5 divalent thiophene ring residue, furan ring residue, pyridine ring residue, pyrimidine ring residue or quinoline ring residue. A 6-membered monocyclic ring or a 2-3 condensed ring may be mentioned.

These aromatic hydrocarbon groups and aromatic heterocyclic groups include alkyl groups having 1 to 6 carbon atoms such as methyl groups and ethyl groups, halogen atoms such as fluorine atoms, and α-haloalkyl groups such as trifluoromethyl groups. You may have a substituent.
Ar ^{1 to} Ar ⁶ include a phenyl group, a naphthyl group, an anthranyl group, a naphthacenyl group, and the like, an aromatic hydrocarbon group that is a 5- or 6-membered monocyclic ring or a 2-4 condensed ring, or a thienyl group, An aromatic heterocyclic group which is a 5- to 6-membered monocyclic ring or a 2-3 condensed ring, such as a furyl group, a pyridyl group, a pyrimidinyl group, or a quinolyl group. These aromatic hydrocarbon groups and aromatic heterocyclic groups have substituents such as alkyl groups such as methyl groups and ethyl groups, halogen atoms such as fluorine atoms, and α-haloalkyl groups such as trifluoromethyl groups. Also good.
The structure represented by the formula (I-2) is preferably represented by the following formula (I-3).

(In formula (I-3), R ^{17 to} R ²⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group which may have a substituent, or an acyl group. A group, an alkoxycarbonyl group, a carboxyl group, an alkoxy group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, R ¹⁷ and R ¹⁸ , R ¹⁹ and R ²⁰ , R ²¹ and R ²² , R ²³ and R ²⁴ may be bonded to each other to form a ring.)

In the above formula (I-3), as R ^{17 to} R ²⁴ , specifically, a hydrogen atom; a halogen atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group; an aralkyl group such as a benzyl group; C2-C6 alkenyl group such as vinyl group; cyano group; amino group; alkylamino group such as diethylamino group and diisopropylamino group; aralkylamino group such as dibenzylamino group and diphenethylamino group; acyl group; A C2-C6 alkoxycarbonyl group such as a carbonyl group or an ethoxycarbonyl group; a carboxyl group; a C1-C6 alkoxy group such as a methoxy group or an ethoxy group; a haloalkyl group such as a trifluoromethyl group; a hydroxyl group; a phenoxy group , Aryloxy groups such as benzyloxy group; aromatic groups such as phenyl group and naphthyl group which may have a substituent A hydrocarbon group; an aromatic heterocyclic group such as a thienyl group and a pyridyl group which may have a substituent.

  Examples of the substituent that the aromatic hydrocarbon group and aromatic heterocyclic group may have include a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; and a carbon number such as a vinyl group. An alkenyl group having 2 to 6 carbon atoms; an alkoxycarbonyl group having 2 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; a phenoxy group and a benzyloxy group Aryloxy group; dialkylamino group such as dimethylamino group and diethylamino group; acyl group such as acetyl group; haloalkyl group such as trifluoromethyl group; cyano group and the like.

R ¹⁷ and R ¹⁸ , R ¹⁹ and R ²⁰ , R ²¹ and R ²² , R ²³ and R ²⁴ are bonded together by adjacent substituents to form a 5- to 7-membered ring such as a benzene ring or a cyclohexane ring. May be.
Although the preferable specific example of a compound represented by the said general formula (I) is shown below, it is not limited to these.

  The organic electroluminescent element of the present invention may use an organometallic complex compound represented by the general formula (II) as a host material in the light emitting layer. As the host material represented by the general formula (II), in particular, an organometallic complex represented by the following general formula (II-1), a mixed ligand complex represented by the following general formula (II-2), or the following A binuclear metal complex represented by the general formula (II-3) is preferred.

(In formula (II-1), M ¹ represents a monovalent to trivalent metal, and k, X ² , ring A ⁰ and ring B ⁰ have the same meanings as in general formula (II).)

(In formula (II-2), M ² represents a trivalent metal, and X ² , ring A ⁰ and ring B ⁰ have the same meanings as in general formula (II). L ¹ represents the following general formula (II- 2a), (II-2b) or (II-2c)
Represents. )

(In the formulas (II-2a), (II-2b) and (II-2c), Ar ^{11 to} Ar ¹⁵ may have an aromatic hydrocarbon group or a substituent which may have a substituent. Represents a good aromatic heterocyclic group, Z ² represents silicon or germanium.)

((II-3) In the formula, M ³ and M ^{3 ′} represent a trivalent metal, X ² , ring A ⁰ and ring B ⁰ have the same meaning as in general formula (II), and X ^{2 ′} represents X ² and ring A ⁰ ′ are synonymous with ring A ^0, and ring B ⁰ ′ is synonymous with ring B ⁰ .
In addition, a plurality of the following structural parts contained in one molecule of the compound represented by the general formulas (II) and (II-1) to (II-3)

(In the general formula (II-3), the following structural moiety exists two by one in one compound)

That is, ring A ⁰ , ring B ⁰ , and X ² (in the case of formula (II-3), ring A ⁰ , ring A ⁰ ′, ring B ⁰ , ring B ⁰
', X ² and X ^2' ) may be the same or different. From the viewpoint of easy synthesis, it is preferable that they are all the same.
Similarly, M ³ and M ^{3 ′} in the compound represented by the general formula (II-3) may be the same or different, and are preferably the same from the viewpoint of easy synthesis.
Ring A ⁰ , ring A ⁰ ′, ring B ⁰ , and ring B ⁰ ′ of the compounds represented by the general formulas (II) and (II-1) to (II-3) are each selected from the following: Those are preferred.

[Ring A ⁰ and Ring A ⁰ ′] is a 5-membered or 6-membered nitrogen-containing aromatic heterocycle optionally having a substituent, and the ring is a 5- or 6-membered aromatic hydrocarbon ring Alternatively, one or two aromatic heterocycles may be condensed to form a condensed ring.
[Ring B ⁰ and Ring B ⁰ ′] A 6-membered aromatic hydrocarbon ring or an aromatic heterocyclic ring which may have a substituent, and a 5- or 6-membered aromatic hydrocarbon ring in the ring Alternatively, one or two aromatic heterocycles may be condensed to form a condensed ring.

Ring A and ring A ⁰ ′ of the compounds represented by the general formulas (II) and (II-1) to (II-3)
, Ring B ⁰ , and ring B ⁰ ′ are each more preferably a single ring, and among them, a ring selected from the following is preferable.
[Ring A ⁰ and Ring A ⁰ ′] each optionally having a substituent, a diazole ring, thiazole ring, oxazole ring, thiadiazole ring, oxadiazole ring, triazole ring, pyridine ring, diazine ring, triazine ring [ Ring B ⁰ and Ring B ⁰ ′], each of which may have a substituent, a benzene ring, a pyridine ring, a diazine ring, a triazine ring, and the general formulas (II) and (II-1) to (II-3) A ring A ^{0 of the} compound represented by:
Most preferably, ring A ⁰ ′, ring B ⁰ , and ring B ⁰ ′ are each selected from the following structural formulae.

(Wherein R ^{31 to} R ³⁷ are each independently a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, an alkoxy group, an alkylamino group) A group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, R ³¹ and R ³² , R ³¹ and R ³³ , R ³⁴ and R ³⁵ , R ³⁵ and R ³⁶ , and R ³⁶ and R ³⁷ may be bonded to each other to form a ring.)

(Wherein R ^{38 to} R ⁴¹ are each independently a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, an alkoxy group, an alkylamino group) A group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, R ³⁸ and R ³⁹ , R ³⁹ and R ⁴⁰ , and R ⁴⁰ and R ⁴¹ may be bonded to each other to form a ring.)

Note the [Ring B ⁰ and ring B ⁰ '] 2 pieces of bonds in the structure of the formula (II) and (II-1) ~ (II -3) in the ring B ⁰ and ring B ^0' of the structure As long as the definition is satisfied, either an oxygen atom or atoms X ² and X ^{2 ′} in ring A ⁰ and ring A ⁰ ′ may be bonded to any one.

Specific examples of R ^{31 to} R ⁴¹ include a hydrogen atom; a halogen atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; an aralkyl group such as a benzyl group; and a C 2 to 6 carbon atom such as a vinyl group. Alkenyl group; cyano group; amino group; acyl group; carboxyl group; alkoxy group having 1 to 6 carbon atoms such as methoxy group and ethoxy group; alkoxycarbonyl group having 2 to 6 carbon atoms such as methoxycarbonyl group and ethoxycarbonyl group; Aryloxy groups such as phenoxy group and benzyloxy group; dialkylamino groups such as diethylamino group and diisopropylamino group; dibenzylamino groups; diaralkylamino groups such as diphenethylamino group; α-haloalkyl groups such as trifluoromethyl group; A hydroxyl group; an optionally substituted aromatic hydrocarbon group such as a phenyl group or a naphthyl group; Also it has good thienyl group, an aromatic heterocyclic group such as pyridyl group.

  Examples of the substituent that the aromatic hydrocarbon group and aromatic heterocyclic group may have include a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; and a carbon number such as a vinyl group. An alkenyl group having 2 to 6 carbon atoms; an alkoxycarbonyl group having 2 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; a phenoxy group and a benzyloxy group Aryloxy group; dialkylamino group such as dimethylamino group and diethylamino group; acyl group such as acetyl group; haloalkyl group such as trifluoromethyl group; cyano group and the like.

Incidentally, R ³¹ and R ^32, R ³¹ and R ^33, R ³⁴ and R ^35, R ³⁵ and R ^36, R ³⁶ and R ^37, R ³⁸ and R ^39, R ³⁹ and R ^40, R ⁴⁰ and R ⁴¹ is Examples of the ring formed by bonding between adjacent groups include a benzene ring or a cyclohexane ring. R ^{31 to} R ⁴¹ are preferably a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a haloalkyl group, or an aromatic hydrocarbon group which may have a substituent, or bonded to adjacent groups. To form a ring.

Metals M ⁰ (M ¹ , M ² ) of the compounds represented by the general formulas (II) and (II-1) to (II-3)
, M ³ and M ^{3 ′} ) are not particularly limited as long as they are metals selected from Groups 1, 2, 3, 12, and 13 of the periodic table, but preferably zinc, aluminum, gallium, beryllium, and Magnesium is mentioned.
Although the preferable specific example of the compound represented by the said general formula (II) and (II-1)-(II-3) is shown below, it is not limited to these.

Moreover, the organic electroluminescent element of this invention may use the compound which has group represented by the said general formula (III) as a host material in a light emitting layer.
In the general formula (III), examples of the ring formed by combining R ⁵¹ and R ⁵² and R ⁵³ and R ⁵⁴ include a benzene ring and a cyclohexane ring.

In the general formula (III), R ^{51 to} R ⁵⁴ are specifically a hydrogen atom; a halogen atom;
An alkyl group having 1 to 6 carbon atoms, such as a methyl group or an ethyl group; an aralkyl group such as a benzyl group; an alkenyl group such as a vinyl group; a cyano group; an amino group; an acyl group; Alkoxy group having 1 to 6 carbon atoms such as methoxycarbonyl group and ethoxycarbonyl group; aryloxy group such as phenoxy group and benzyloxy group; dialkylamino group such as diethylamino group and diisopropylamino group; Diaralkylamino groups such as amino groups and diphenethylamino groups; α-haloalkyl groups such as trifluoromethyl groups; hydroxyl groups; optionally substituted aromatic hydrocarbon groups such as phenyl groups and naphthyl groups; Represents an aromatic heterocyclic group such as a thienyl group and a pyridyl group which may have a group, Halogen atoms such as fluorine atoms; alkyl groups having 1 to 6 carbon atoms such as methyl groups and ethyl groups; alkenyl groups such as vinyl groups; alkoxycarbonyl groups having 1 to 6 carbon atoms such as methoxycarbonyl groups and ethoxycarbonyl groups; C1-C6 alkoxy groups such as methoxy group and ethoxy group; aryloxy groups such as phenoxy group and benzyloxy group; dialkylamino groups such as dimethylamino group and diethylamino group; acyl groups such as acetyl group; trifluoromethyl A haloalkyl group such as a group, and a cyano group.
Although the preferable specific example of group represented by the said general formula (III) is shown below, it is not limited to these.

The compound having a group represented by the general formula (III) may be a low molecule or a polymer. In the case of a polymer, it may be contained in the main chain or may be contained as a side chain.
This compound is preferably a low molecular weight compound having a molecular weight of about 400 to 1200, and the compound having a group represented by the general formula (III) preferably has a total number of rings of 6 to 20 as the whole compound. More preferably, it is 7-18. The compound having a group represented by the general formula (III) is preferably a compound having 2 to 3 units represented by the general formula (III) in the molecule.

Among them, the group represented by the general formula (III) is particularly preferably the above (S-1) or (S-2).
The compound having a group represented by the general formula (III) is represented by the following general formula (III-1) or (III-
It is preferable that it is a compound represented by 2).

Wherein R ^{55 to} R ⁶² are each independently a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, an allyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, or an alkoxy group. , An alkylamino group, an α-haloalkyl group, a hydroxyl group, an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group, R ⁵⁵ and R ⁵⁶ , R ⁵⁷ and R ⁵⁸ , R ⁵⁹ and R ^60, R ⁶¹ and R ⁶² each may be bonded to each other to form a ring in .X ⁴
And X ⁵ each independently represents an oxygen atom or a sulfur atom, and Q ¹ represents a divalent linking group composed of an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group. )

(In the formula, R ^{63 to} R ⁷⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, an allyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, or an alkoxy group. , An alkylamino group, an α-haloalkyl group, a hydroxyl group, an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group, R ⁶³ and R ⁶⁴ ,
R ⁶⁵ and R ⁶⁶ , R ⁶⁷ and R ⁶⁸ , R ⁶⁹ and R ⁷⁰ , R ⁷¹ and R ⁷² , and R ⁷³ and R ⁷⁴ may be bonded to each other to form a ring. X ^{6 to} X ⁸ each independently represents an oxygen atom or a sulfur atom, and Q ² represents a trivalent linking group consisting of an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group. . )

In the general formula (III-1), the R ⁵⁵ to R ⁶² are each independently a hydrogen atom, a halogen atom, an aralkyl group such as benzyl group; vinyl alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group An alkenyl group such as a group; a cyano group; an amino group; an acyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; an alkoxycarbonyl group having 1 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; Aryloxy groups such as phenoxy group and benzyloxy group; dialkylamino groups such as diethylamino group and diisopropylamino group; diaralkylamino groups such as dibenzylamino group and diphenethylamino group; α-haloalkyl groups such as trifluoromethyl group; A hydroxyl group; an optionally substituted aromatic hydrocarbon group such as a phenyl group or a naphthyl group; Represents an aromatic heterocyclic group such as a thienyl group and a pyridyl group, and examples of the substituent include a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; a vinyl group and the like An alkoxycarbonyl group having 1 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; an aryloxy group such as a phenoxy group and a benzyloxy group A dialkylamino group such as a dimethylamino group or a diethylamino group, an acyl group such as an acetyl group, a haloalkyl group such as a trifluoromethyl group, or a cyano group. R ⁵⁵ and R ^56, R ⁵⁷ and R ^58, R ⁵⁹ and R ^60, R ⁶¹ and R ⁶² are respectively bonded, a benzene ring, may form a cyclohexane ring.

X ^{4 to} X ⁵ each independently represents an oxygen atom or a sulfur atom.
Q ¹ represents a divalent linking group composed of an aromatic aromatic hydrocarbon group or aromatic heterocyclic group which may have a substituent, and the substituent includes a halogen atom such as a fluorine atom; a methyl group An alkyl group having 1 to 6 carbon atoms such as an ethyl group; an alkenyl group having 2 to 6 carbon atoms such as a vinyl group; an alkoxycarbonyl group having 2 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; a methoxy group and an ethoxy group An alkoxy group having 1 to 6 carbon atoms such as a group; an aryloxy group such as a phenoxy group and a benzyloxy group; a dialkylamino group such as a dimethylamino group and a diethylamino group; an acyl group such as an acetyl group; and a haloalkyl such as a trifluoromethyl group Group, cyano group and the like.
Preferred examples of the linking group Q ¹ are shown below.

Among these, the linking group Q ¹ is (A-2), (A-6), (A-8), (A-10).
Or (A-12) is preferable. These linking groups Q ¹ have a ring structure (S
The compound having -1) or (S-2) is most preferable.
Although the preferable specific example of a compound represented by the said general formula (III-1) is shown in the following table | surfaces, it is not limited to these.

In the general formula (III-2), R ^{63 to} R ⁷⁴ are each independently a hydrogen atom; a halogen atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group; an aralkyl group such as a benzyl group; An alkenyl group such as a group; a cyano group; an amino group; an acyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; an alkoxycarbonyl group having 1 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; Aryloxy groups such as phenoxy group and benzyloxy group; dialkylamino groups such as diethylamino group and diisopropylamino group; diaralkylamino groups such as dibenzylamino group and diphenethylamino group; α-haloalkyl groups such as trifluoromethyl group; A hydroxyl group; an optionally substituted aromatic hydrocarbon group such as a phenyl group or a naphthyl group; Represents an aromatic heterocyclic group such as a thienyl group and a pyridyl group, and examples of the substituent include a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; a vinyl group and the like An alkoxycarbonyl group having 1 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; an aryloxy group such as a phenoxy group and a benzyloxy group A dialkylamino group such as a dimethylamino group or a diethylamino group, an acyl group such as an acetyl group, a haloalkyl group such as a trifluoromethyl group, or a cyano group. R ⁶³ and R ⁶⁴ , R ⁶⁵ and R ⁶⁶ , R ⁶⁷ and R ⁶⁸ , R ⁶⁹ and R ⁷⁰ , R ⁷¹ and R ⁷² , R ⁷³ and R ⁷⁴ are bonded to each other to form a benzene ring, a cyclohexane ring, etc. You may do it.

X ^{6 to} X ⁸ each independently represents an oxygen atom or a sulfur atom.
Q ² represents a trivalent linking group comprising an aromatic aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, and the substituent includes a halogen atom such as a fluorine atom; a methyl group An alkyl group having 1 to 6 carbon atoms such as an ethyl group; an alkenyl group having 2 to 6 carbon atoms such as a vinyl group; an alkoxycarbonyl group having 2 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; a methoxy group and an ethoxy group An alkoxy group having 1 to 6 carbon atoms such as a group; an aryloxy group such as a phenoxy group and a benzyloxy group; a dialkylamino group such as a dimethylamino group and a diethylamino group; an acyl group such as an acetyl group; and a haloalkyl such as a trifluoromethyl group Group, cyano group and the like.

Preferred examples of the linking group Q ² are shown below.

Among these, the linking group Q ² is preferably (B-1), (B-2) or (B-7). Most preferably, it has these linking groups and has (S-1) or (S-2) as the ring structure.
Preferred specific examples of the compound represented by the general formula (III-2) are shown in the following table, but are not limited thereto.

The compound represented by the general formula (I), the compound represented by the general formula (II), and the compound having a group represented by the general formula (III) are each only one type in the light emitting layer. It may be included, and two or more of each may be included. Moreover, you may use together the compound represented by a different general formula.
As the host material, in addition to the general formulas (I) to (III), the following compounds may be used.

(In the above formula (IV), the 8-hydroxyquinoline structure as a ligand is a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, or a carbon such as a methyl group, an ethyl group or a t-butyl group. It may be substituted with a linear or branched alkyl group of 1 to 5.
The three ligands in one compound may be the same structure or different. )
As described above, the host material may be used in combination of a plurality of compounds that can be represented by the same general formula, or may be used in combination of two or more compounds that cannot be represented by the same general formula.

In the organic electroluminescent device of the present invention, the compound represented by the general formula (I) or the compound represented by the general formula (IV) is particularly preferable as the host material of the light emitting layer.
Next, the structure of the organic electroluminescent element of the present invention will be described with reference to the drawings. However, the structure of the organic electroluminescent element of the present invention is not limited to the illustrated one.

1 to 3 are cross-sectional views schematically showing an embodiment of the organic electroluminescence device of the present invention, wherein 1 is a substrate, 2 is an anode, 3 is an anode buffer layer, 4 is a hole transport layer, and 5 is light emission. 6 represents a hole blocking layer, 7 represents an electron transport layer, and 8 represents a cathode. In the following, description will be made centering on the element shown in FIG.
The substrate 1 serves as a support for the organic electroluminescence device, and a quartz or glass plate, a metal plate or a metal foil, a plastic film, a sheet, or the like is used. In particular, a glass plate, a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, polysulfone, or a film is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic electroluminescent element may be deteriorated by the outside air that has passed through the substrate, which is not preferable. For this reason, a method of providing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

  An anode 2 is provided on the substrate 1, and the anode 2 plays a role of hole injection into the hole transport layer 4. The anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or poly It is composed of conductive polymers such as (3-methylthiophene), polypyrrole, and polyaniline. In general, the anode 2 is often formed by a sputtering method, a vacuum deposition method, or the like. Further, when the anode 2 is formed of metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, and conductive polymer fine powder, It can also be formed by dispersing and coating on the substrate 1. Further, when the anode 2 is formed of a conductive polymer, a polymerized thin film can be directly formed on the substrate 1 by electrolytic polymerization, or a conductive polymer can be applied to the substrate 1 (Appl). Phys. Lett., 60, 2711, 1992).

The anode 2 usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.
The thickness of the anode 2 varies depending on the required transparency. When transparency is required, the visible light transmittance is usually 60% or more, preferably 80% or more. In this case, the thickness of the anode is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably about 500 nm or less. When it may be opaque, the thickness of the anode 2 is arbitrary, and if desired, it may be formed of metal to serve as the substrate 1.

In the element having the configuration shown in FIG. 1, a hole transport layer 4 is provided on the anode 2. As conditions required for the material of the hole transport layer, it is necessary that the material has a high hole injection efficiency from the anode and can efficiently transport the injected holes. For this purpose, the ionization potential is small, the transparency to visible light is high, the hole mobility is large, the stability is high, and trapping impurities are unlikely to be generated during manufacturing or use. Required. Further, in order to contact the light emitting layer 5, it is required not to quench the light emitted from the light emitting layer or to form an exciplex with the light emitting layer to reduce the efficiency. In addition to the above general requirements, when the application for in-vehicle display is considered, the element is further required to have heat resistance. Therefore, a material having a Tg value of 85 ° C. or higher is desirable.

  Examples of such a hole transport material include two or more tertiary amines represented by 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl, and two or more Aromatics having a starburst structure such as aromatic diamines in which condensed aromatic rings are substituted with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681), 4,4 ', 4'-tris (1-naphthylphenylamino) triphenylamine Group amine compounds (J. Lumin., 72-74, 985, 1997), aromatic amine compounds consisting of tetramers of triphenylamine (Chem. Commun., 2175, 1996), 2, 2 Spiro compounds such as', 7,7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, 91, 209) , 1997). These compounds may be used alone or in combination as necessary.

In addition to the above compounds, polyarylene ether sulfone (Polym. Adv. Tech.) Containing polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Laid-Open No. 7-53953), and tetraphenylbenzidine as the material of the hole transport layer 4 is used. , 7, p. 33, 1996).
The hole transport layer 4 may be formed by a normal coating method such as a spray method, a printing method, a spin coating method, a dip coating method, or a die coating method, a wet film forming method such as various printing methods such as an ink jet method or a screen printing method, or a vacuum. It can be formed by a dry film formation method such as a vapor deposition method.

  In the case of the coating method, one or more hole transport materials are added, and if necessary, additives such as binder resins and coating property improving agents that do not trap holes are added and dissolved in a suitable solvent. A solution is prepared, applied onto the anode 2 by a method such as spin coating, and dried to form the hole transport layer 4. Examples of the binder resin include polycarbonate, polyarylate, and polyester. When the binder resin is added in a large amount, the hole mobility is lowered. Therefore, it is desirable that the binder resin be less, and usually 50% by weight or less is preferable.

In the case of the vacuum evaporation method, the hole transport material is put in a crucible installed in a vacuum vessel, the inside of the vacuum vessel is evacuated to about 10 ⁻⁴ Pa with a suitable vacuum pump, and then the crucible is heated, The hole transport material is evaporated and a hole transport layer 4 is formed on the substrate 1 on which the anode 2 is formed, which is placed facing the crucible.
The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and is usually 300 nm or less, preferably 100 nm or less. In order to uniformly form such a thin film, a vacuum deposition method is generally used.

  A light emitting layer 5 is provided on the hole transport layer 4. The light emitting layer 5 contains at least the compound represented by the general formula (i) (the organometallic complex of the present invention), and usually further contains the various host materials described above. This light-emitting layer 5 is composed of holes injected from the anode 2 to move through the hole transport layer 4 and electrons injected from the cathode 8 to move through the hole blocking layer 6 between electrodes to which an electric field is applied. Excited by recombination, shows strong emission.

In addition, the light emitting layer 5 may contain components other than the organometallic complex and host material of this invention in the range which does not impair the performance of this invention.
For example, in addition to (1) the host material and (2) the organometallic complex of the present invention, (3) phosphorescence is emitted at room temperature, and the maximum emission wavelength is shorter than the maximum emission wavelength of (2). It may contain the compound which is. This is because, when the compound (3) is used in combination, it serves as a sensitizer and the light emission of the organometallic complex of the present invention is enhanced.

The above (3) may be selected from the compounds represented by the general formula (i) of the present invention, and is a known phosphorescent compound described in various documents and patents cited in this specification. You may choose from. As long as the condition (3) is satisfied, the structure is not limited.
The content of the organometallic complex of the present invention represented by the general formula (i) exhibiting phosphorescence emission is preferably 0.1% by weight or more and preferably 30% by weight or less with respect to the entire light emitting layer. If the lower limit is not reached, it may not be possible to contribute to improving the luminous efficiency of the device. If the upper limit is exceeded, concentration quenching may occur due to the formation of a dimer between organometallic complexes, etc. There is. The amount of the phosphorescent dopant in the light emitting layer exhibiting phosphorescence tends to be preferably slightly larger than the amount of the fluorescent dye (dopant) contained in the light emitting layer in a conventional device using fluorescence (singlet). There is.

When the fluorescent dye is contained in the light emitting layer together with the phosphorescent dopant, the amount of the fluorescent dye is preferably 0.05% by weight or more, and more preferably 0.1% by weight or more. Moreover, 10 weight% or less is preferable and 3 weight% or less is more preferable.
The compound of the present invention represented by the general formula (i) may be uniformly distributed in the light emitting layer, or may be nonuniformly distributed in the film thickness direction.

The thickness of the light emitting layer 5 is usually 3 nm or more, preferably 5 nm or more, and is usually 200 nm or less, preferably 100 nm or less.
In addition, the light emitting layer 5 may contain components other than the above in the range which does not impair the performance of this invention. The light emitting layer is formed into a thin film by the same method as the hole transport layer 4.
The light emitting layer can also be formed by the same method as the hole transport layer. A method for doping the above-described fluorescent dye and / or phosphorescent dye (phosphorescent dopant) into the host material of the light emitting layer will be described below.

In the case of coating, the above light emitting layer host material, dope dye, and if necessary, additives such as a binder resin that does not become an electron trap or a light quenching quencher, and a coating property improving agent such as a leveling agent are added and dissolved. The applied coating solution is prepared, applied onto the hole transport layer 4 by a method such as spin coating, and dried to form the light emitting layer 5. Examples of the binder resin include polycarbonate, polyarylate, and polyester. When the amount of the binder resin added is large, the hole / electron mobility is lowered. Therefore, the smaller amount is desirable, and 50% by weight or less is preferable.

In the case of the vacuum deposition method, the host material is put in a crucible installed in a vacuum vessel, the dye to be doped is put in another crucible, and the inside of the vacuum vessel is 1.0 × 10 ⁻⁴ Torr with an appropriate vacuum pump. After evacuating to a degree, each crucible is heated and evaporated simultaneously to form a layer on the substrate placed opposite the crucible. As another method, a mixture of the above materials in a predetermined ratio may be evaporated using the same crucible.

When each said dopant is doped in a light emitting layer, although doped uniformly in the film thickness direction of a light emitting layer, there may exist concentration distribution in a film thickness direction. For example, it may be doped only in the vicinity of the interface with the hole transport layer, or conversely, it may be doped in the vicinity of the interface of the hole blocking layer.
The light emitting layer can also be formed by the same method as the hole transport layer, but usually a vacuum deposition method is used.

In the element shown in FIG. 1, the hole blocking layer 6 is laminated on the light emitting layer 5 so as to be in contact with the cathode side interface of the light emitting layer 5.
The hole blocking layer has a role of blocking the holes moving from the hole transport layer from reaching the cathode, and a compound that can efficiently transport the electrons injected from the cathode toward the light emitting layer. Preferably it is formed. The physical properties required for the material constituting the hole blocking layer are required to have high electron mobility and low hole mobility. The hole blocking layer 6 has a function of confining holes and electrons in the light emitting layer and improving luminous efficiency.

  The ionization potential of the hole blocking layer used in the present invention is preferably at least 0.1 eV greater than the ionization potential of the light-emitting layer (or the ionization potential of the host material when the light-emitting layer contains a host material and a dopant). The ionization potential is defined by the energy required to emit electrons at the HOMO (highest occupied molecular orbital) level of the material to the vacuum level. The ionization potential can be defined directly by photoelectron spectroscopy or can be determined by correcting the electrochemically measured oxidation potential relative to the reference electrode. In the case of the latter method, for example, when a saturated sweet potato electrode (SCE) is used as a reference electrode,

  Furthermore, the electron affinity (EA) of the hole blocking layer used in the present invention is equivalent to the electron affinity of the light emitting layer (when the light emitting layer contains a host material and a dopant, the electron affinity of the host material). The above is preferable. Similar to the ionization potential, the electron affinity is also defined by the energy at which the electrons in the vacuum level fall to the LUMO (lowest unoccupied molecular orbital) level of the material and stabilize, with the vacuum level as a reference. The electron affinity can be obtained by subtracting the optical band gap from the above-mentioned ionization potential, or similarly obtained from the electrochemical reduction potential by the following formula.

Therefore, the hole blocking layer used in the present invention uses an oxidation potential and a reduction potential, and (the oxidation potential of the hole blocking material) − (the oxidation potential of the light emitting material) ≧ 0.1 V (the reduction of the hole blocking material). It can also be expressed as (potential) ≧ (reduction potential of the light emitting material).
Further, in the case of an element having an electron transport layer described later, the electron affinity of the hole blocking layer is preferably equal to or less than that of the electron transport layer.
(Reduction potential of electron transport material) ≧ (Reduction potential of hole blocking material) ≧ (Reduction potential of light emitting material)
As a hole blocking material satisfying such conditions, a mixed ligand complex represented by the following general formula (VII) is preferably used.

(Wherein R ^{16 to} R ²¹ represent a hydrogen atom or an arbitrary substituent. M ⁸ represents a metal atom selected from aluminum, gallium, and indium. L ⁵ represents a general formula (VIIa) shown below, ( It is represented by either VIIb) or (VIIc).

(In the formula, Ar ^{11 to} Ar ¹⁵ represent an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and Z ³ represents silicon or germanium. To express.)
In the general formula (VII), R ^{16 to} R ²¹ represent a hydrogen atom or an arbitrary substituent, preferably a hydrogen atom; a halogen atom such as chlorine or bromine; a carbon number of 1 to 6 such as a methyl group or an ethyl group. An aralkyl group such as a benzyl group; an alkenyl group having 2 to 6 carbon atoms such as a vinyl group; a cyano group; an amino group; an acyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; An alkoxycarbonyl group having 2 to 6 carbon atoms such as a carbonyl group and an ethoxycarbonyl group; a carboxyl group; an aryloxy group such as a phenoxy group and a benzyloxy group; a dialkylamino group such as a diethylamino group and a diisopropylamino group; a dibenzylamino group; Diaralkylamino groups such as diphenethylamino groups; α-haloalkyl groups such as trifluoromethyl groups; hydroxyl groups; substituents Represents an aromatic hydrocarbon group such as a phenyl group and naphthyl group which may have a substituent; an aromatic heterocyclic group such as a thienyl group and a pyridyl group which may have a substituent.

Examples of the substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group may have include: a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; and a carbon number such as a vinyl group. An alkenyl group having 2 to 6 carbon atoms; an alkoxycarbonyl group having 2 to 6 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; a phenoxy group and a benzyloxy group Aryloxy groups; dialkylamino groups such as dimethylamino groups and diethylamino groups; acyl groups such as acetyl groups; haloalkyl groups such as trifluoromethyl groups; cyano groups and the like. R ¹⁶ to R ²¹ are more preferably a hydrogen atom, an alkyl group, a halogen atom or a cyano group. R ¹⁹ is particularly preferably a cyano group.

In the above formula (VII), as Ar ^{11 to} Ar ¹⁵ , specifically, an aromatic hydrocarbon group such as phenyl group, biphenyl group, naphthyl group or the like which may have a substituent, thienyl group, pyridyl group, etc. Represents an aromatic heterocyclic group.
Preferred specific examples of the compound represented by the general formula (VII) are shown below, but are not limited thereto.

  In addition, these compounds may be used independently in a hole-blocking layer, and may be mixed and used as needed.

As the hole blocking material, in addition to the mixed ligand complex of the general formula (VII), a compound having at least one 1,2,4-triazole ring residue represented by the following structural formula may be used. it can.
Specific examples of the compound having at least one 1,2,4-triazole ring residue represented by the above structural formula are shown below.

  Examples of the hole blocking material further include compounds having at least one phenanthroline ring represented by the following structural formula.

  Specific examples of the compound having at least one phenanthroline ring represented by the above structural formula are shown below.

  The film thickness of the hole blocking layer 6 is usually 0.3 or more, preferably 0.5 nm or more, and is usually 100 nm or less, preferably 50 nm or less. The hole blocking layer can also be formed by the same method as the hole transporting layer, but usually a vacuum deposition method is used.

  The cathode 8 serves to inject electrons into the light emitting layer 5 through the hole blocking layer 6. The material used for the cathode 8 can be the material used for the anode 2, but a metal having a low work function is preferable for efficient electron injection, such as tin, magnesium, indium, calcium, A suitable metal such as aluminum or silver or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy. Furthermore, inserting an ultrathin insulating film (0.1 to 5 nm) such as LiF, MgF2, or Li2O at the interface between the cathode and the light emitting layer or the electron transport layer is also an effective method for improving the efficiency of the device (Appl Phys., Lett., 70, 152, 1997; JP-A-10-74586; IEEE Trans. Electron. Devices, 44, 1245, 1997). The film thickness of the cathode 8 is usually the same as that of the anode 2. For the purpose of protecting the cathode made of a low work function metal, further laminating a metal layer having a high work function and stable to the atmosphere on the cathode increases the stability of the device. For this purpose, metals such as aluminum, silver, copper, nickel, chromium, gold, platinum are used.

For the purpose of further improving the luminous efficiency of the device, an electron transport layer 7 may be provided between the hole blocking layer 6 and the cathode 8 as shown in FIGS. The electron transport layer 7 is formed of a compound that can efficiently transport electrons injected from the cathode between the electrodes to which an electric field is applied in the direction of the hole blocking layer 6.
Materials satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, oxadiazole derivatives, Styryl biphenyl derivative, silole derivative, 3- or 5-hydroxyflavone metal complex, benzoxazole metal complex, benzothiazole metal complex, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), quinoxaline compound No. 207169), phenanthroline derivatives (Japanese Patent Laid-Open No. 5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinonediimine, n-type hydrogenated amorphous silicon carbide, n-type sulfide Examples include zinc and n-type zinc selenide.

The thickness of the electron transport layer 6 is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.
The electron transport layer 7 is formed by laminating on the hole blocking layer 6 by a coating method or a vacuum deposition method in the same manner as the hole transport layer 4. Usually, a vacuum deposition method is used.
An anode buffer layer 3 is also inserted between the hole transport layer 4 and the anode 2 for the purpose of further improving the efficiency of hole injection and improving the adhesion of the entire organic layer to the anode. (See FIG. 3). By inserting the anode buffer layer 3, the driving voltage of the initial element is lowered, and at the same time, an increase in voltage when the element is continuously driven with a constant current is suppressed. As conditions required for the material used for the anode buffer layer, it is possible to form a uniform thin film with good contact with the anode and thermally stable, that is, the melting point and the glass transition temperature are high, and the melting point is 300 ° C. or higher. The glass transition temperature is preferably 100 ° C. or higher. Furthermore, the ionization potential is low, hole injection from the anode is easy, and the hole mobility is high.

For this purpose, porphyrin derivatives, phthalocyanine compounds (Japanese Unexamined Patent Publication No. 63-295695), hydrazone compounds, alkoxy-substituted aromatic diamine derivatives, p- (9-anthryl) have been used as materials for the anode buffer layer 3 so far. ) -N, N'-di-p-tolylaniline, polythienylene vinylene, poly-p-phenylene vinylene, polyaniline (Appl. Phys. Lett., 64, 1245, 1994), polythiophene (OpticalMaterials, 9 Vol. 125, 1998), organic compounds such as starbust aromatic triamine (JP-A-4-308688), sputtered carbon film (Synth. Met. 91, 73, 1997) Metal oxides such as vanadium oxide, ruthenium oxide, molybdenum oxide (J. Phys. D, 29, 2750, 1996) have been reported.

  In addition, a layer containing a hole injection / transporting low molecular organic compound and an electron accepting compound (described in JP-A-11-251067, JP-A-2000-159221, etc.), an aromatic amino group, etc. A layer obtained by doping the contained non-conjugated polymer compound with an electron-accepting compound as necessary (Japanese Patent Laid-Open Nos. 11-135262, 11-283750, 2000-36390, Examples include JP 2000-150168, JP-A 2001-223084, and WO 97/33193), or layers containing a conductive polymer such as polythiophene (JP-A 10-92584). It is not limited to.

As the anode buffer layer material, either a low molecular compound or a high molecular compound can be used.
Of the low molecular weight compounds, those often used include porphine compounds and phthalocyanine compounds. These compounds may have a central metal or may be metal-free. Preferred examples of these compounds include the following compounds:
Porphin
5,10,15,20-Tetraphenyl-21H, 23H-porphine
5,10,15,20-Tetraphenyl-21H, 23H-porphine cobalt (II)
5,10,15,20-Tetraphenyl-21H, 23H-porphine copper (II)
5,10,15,20-Tetraphenyl-21H, 23H-porphine zinc (II)
5,10,15,20-Tetraphenyl-21H, 23H-porphine vanadium (IV) oxide
5,10,15,20-Tetra (4-pyridyl) -21H, 23H-porphine
29H, 31H-phthalocyanine copper (II) phthalocyanine zinc (II) phthalocyanine titanium phthalocyanine oxide magnesium phthalocyanine lead phthalocyanine copper (II) 4,4'4 '', 4 '''-tetraaza-29H, 31H-phthalocyanine anode buffer layer In this case, a thin film can be formed in the same manner as the hole transport layer, but in the case of an inorganic material, a sputtering method, an electron beam evaporation method, or a plasma CVD method is further used.

When the anode buffer layer 3 formed as described above is formed using a low molecular weight compound, the lower limit is usually 3 nm, preferably about 10 nm, and the upper limit is usually 100 nm, preferably about 50 nm. is there.
When using a polymer compound, for example, the polymer compound or the electron-accepting compound, and if necessary, additives such as a binder resin and a coating agent such as a leveling agent that do not trap holes are added and dissolved. A coating solution is prepared, applied to the anode 2 by a normal coating method such as a spray method, a printing method, a spin coating method, a dip coating method, a die coating method, an ink jet method or the like, and dried to form the anode buffer layer 3. A thin film can be formed. Examples of the binder resin include polycarbonate, polyarylate, and polyester. Since the binder resin may reduce hole mobility when the content of the binder resin is large, it is desirable that the content of the binder resin in the anode buffer layer 3 is 50% by weight or less.

Alternatively, a thin film may be formed in advance on a medium such as a film, a support substrate, or a roll by the above-described thin film forming method, and the thin film on the medium is thermally or pressure transferred onto the anode 2. it can.
As described above, the lower limit of the film thickness of the anode buffer layer 3 formed using the polymer compound is usually 5 nm, preferably about 10 nm, and the upper limit is usually about 1000 nm, preferably about 500 nm.

The organic electroluminescence device of the present invention has a structure opposite to that shown in FIG. 1, that is, a cathode 8, a hole blocking layer 6, a light emitting layer 5, a hole transport layer 4 and an anode 2 can be laminated on a substrate in this order. As described above, it is also possible to provide the organic electroluminescence device of the present invention between two substrates, at least one of which is highly transparent. Similarly, the layers can be stacked in the reverse order of the layer configuration shown in FIG. 2 or FIG. Moreover, in any layer structure of FIGS. 1-3, in the range which does not deviate from the meaning of this invention, it may have arbitrary layers other than the above-mentioned, and the layer which has the function of several said layers together By providing, it is possible to appropriately modify the layer structure, for example.

Alternatively, the top emission structure and both the cathode and anode can be made transmissive using transparent electrodes.
The present invention can be applied to any of an organic electroluminescent element having a single element, an element having a structure arranged in an array, and a structure having an anode and a cathode arranged in an XY matrix.

  According to the organic electroluminescent element of the present invention, an element having good color purity and greatly improved driving stability can be obtained by incorporating a compound having a specific skeleton in the hole blocking layer. In particular, in a blue (fluorescent) light-emitting element or phosphorescent light-emitting element in which formation of a hole blocking layer has been difficult due to difficulty in material selection, an element excellent in luminous efficiency, emission color purity, and driving stability can be obtained. Therefore, it can exhibit excellent performance in application to full-color or multi-color panels.

EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.
(Synthesis Example 1)

4. 2-bromo-4,5-difluoroanisole in dehydrated THF solution under nitrogen gas atmosphere;
6 g and 1.5 g of tetrakistriphenylphosphine palladium (0) were added, and 50 mL of a 2-pyridylzinc bromide 0.5 M solution was added dropwise at room temperature, followed by heating to 80 ° C. and refluxing for 6 hours. After completion of the reaction, the solvent was distilled off, water was added, and extraction with hexane was repeated several times. After drying the organic layer with magnesium sulfate, the solvent was removed and purification by column chromatography was performed to obtain 1.5 g of a yellow oil. From the mass spectrum measurement result of the obtained compound, it was confirmed that it was the target product.
M / z: 221
Example 1

@0013

@ 0013

To 920 mg of the compound obtained in Synthesis Example 1 and 780 mg of iridium trichloride trihydrate, 20 mL of 2-ethoxyethanol and 5 mL of water were added and reacted at 120 ° C. for 11 hours under nitrogen. After cooling to room temperature, 30 mL of water was added and the precipitate was filtered. The resulting precipitate and 488 mg of sodium acetyl acetate were further reacted in 20 mL of 2-ethoxyethanol at 80 ° C. for 3 hours in a nitrogen atmosphere. After completion of the reaction, water was added and the resulting crude product was filtered and dried. Thereafter, purification was performed by column chromatography to obtain 600 mg of yellow crystals. From the mass measurement result of the obtained compound, it was confirmed that it was the target product. (M / e: 732) The fluorescence emission spectrum of a methylene chloride solution (4.0 × 10 ⁻⁵ M) of the obtained compound is shown in FIG.

  Thus, the organometallic complex of the present invention emits blue light. In addition, since the organometallic complex of the present invention has high chemical and electrical stability, the use of the complex can provide an organic electroluminescence device that has high luminous efficiency and can be driven stably for a long period of time.

It is typical sectional drawing which showed an example of embodiment of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of embodiment of the organic electroluminescent element of this invention. It is typical sectional drawing which showed another example of embodiment of the organic electroluminescent element of this invention. It is the fluorescence emission spectrum in the solution of the compound obtained in Example 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Anode buffer layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Cathode

Claims (9)

An organometallic complex represented by the following general formula (i).

(Wherein X and Y are each independently a fluorine atom, an alkyl group having 1 to 15 carbon atoms substituted with at least one fluorine atom, or an alkyl group having 1 to 15 carbon atoms substituted with at least one fluorine atom) An alkoxy group, an alkoxyalkyl group having 2 to 30 carbon atoms substituted with at least one fluorine atom, an alkoxyalkoxy group having 2 to 30 carbon atoms substituted with at least one fluorine atom, and at least one fluorine atom; An alkylamino group having 1 or 2 substituted alkyl chains having 1 to 10 carbon atoms, and an aryl having 1 or 2 aromatic hydrocarbon groups having 6 to 18 carbon atoms substituted by at least one fluorine atom An amino group, an acylamino group having one or two acyl group moieties of 2 to 30 carbon atoms substituted with at least one fluorine atom, at least one fluorine atom; Substituted alkylthio group having 1 to 15 carbon atoms in the atom, at least one aromatic hydrocarbon group having 6 to 18 carbon atoms which is substituted with a fluorine atom, -R ¹⁰¹ C
OR ¹⁰² , —OR ¹⁰³ COR ¹⁰⁴ , —COR ¹⁰⁵ , and —OCOR ¹⁰⁶ (where R ^{101 to} R ¹⁰⁶ each independently represents an alkyl group having 1 to 15 carbon atoms substituted with at least one fluorine atom, or Represents an alkylene group.) Represents an electron-withdrawing group selected from the group consisting of: X and Y which are the electron-withdrawing groups may be bonded to each other to form a 5- or 6-membered ring substituted with at least one fluorine atom .
Z has a hydroxyl group, a halogen atom or an alkyl group having 1 to 4 carbon atoms as a substituent, and an alkyl group having 1 to 15 carbon atoms, a halogen atom or an alkyl group having 1 to 4 carbon atoms as a substituent. An optionally substituted alkoxyl group having 1 to 10 carbon atoms, a halogen atom or an alkyl group having 1 to 4 carbon atoms, which may have a substituent, and an aromatic hydrocarbon group having 6 to 18 carbon atoms , and halogen Aromatics consisting of 5- or 6-membered monocyclic or 2-4 condensed rings containing oxygen atoms, nitrogen atoms or sulfur atoms which may have an atom or an alkyl group having 1 to 4 carbon atoms as a substituent It represents a substituent selected from the group consisting of heterocyclic groups.
M represents Re, Ru, Co, Ir, Pt, or Au, and L represents a monovalent bidentate ligand that forms a 5-membered ring or a 6-membered ring with the central metal M at the time of complex formation. n represents the valence of the metal M and is an integer of 1 to 3.
Ring A is a 5- or 6-membered ring optionally having a substituent selected from the group consisting of a fluorine atom, an acetyl group, an alkyl group having 1 to 5 carbon atoms , and an alkoxyl group having 1 to 5 carbon atoms. Represents an aromatic heterocycle.
Z and ring A may be bonded to each other to form a 5- or 6-membered ring which may contain an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom.
X ¹ represents a carbon atom or a nitrogen atom.
In the formula

Represents a single bond or a double bond. ) The organometallic complex according to claim 1, which has a molecular weight of 500 or more and 5000 or less. The organometallic complex according to claim 1 or 2, wherein the maximum emission wavelength is 480 nm or less. A luminescent material comprising the organometallic complex according to any one of claims 1 to 3. The organic electroluminescent element material which comprises the organometallic complex as described in any one of Claim 1 thru | or 3. An organic electroluminescent device in which an anode, a light emitting layer, and a cathode are sequentially laminated on a substrate, characterized in that it has a layer containing the organometallic complex according to any one of claims 1 to 3. An organic electroluminescent device. The organic electroluminescent element of Claim 6 whose layer containing the organometallic complex as described in any one of Claim 1 thru | or 3 is a light emitting layer. The light emitting layer contains a host material having hole injection / transport property or electron injection / transport property, and the host material is doped with the organometallic complex according to any one of claims 1 to 3. The organic electroluminescent element according to claim 7. Furthermore, the organic electroluminescent element of Claim 7 or 8 which has a hole-blocking layer which contact | connects the cathode side interface of a light emitting layer.

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