JP4810805B2 - Organic compound, charge transport material, organic electroluminescent element material, and organic electroluminescent element - Google Patents

Description

The present invention relates to a novel organic compound, relates the charge transport material, more particularly a high heat resistance, and electrical oxidation and reduction receiving stable organic compounds also relates the charge transport material.

Conventionally, as a thin film type electroluminescent (EL) element, ZnS, CaS, SrS, etc., which are inorganic material II-VI compound semiconductors, Mn or rare earth elements (Eu, Ce, Tb, Sm, etc.) that are emission centers. ) Is generally used, but an EL element made from the above inorganic material is
1) AC drive is required (50-1000Hz),
2) High driving voltage (~ 200V),
3) Full color is difficult (especially blue),
4) There is a problem that the cost of the peripheral drive circuit is high.

  However, in recent years, EL devices using organic thin films have been developed to improve the above problems. In particular, in order to improve luminous efficiency, the type of electrode is optimized for the purpose of improving the efficiency of carrier injection from the electrode, and a hole transporting layer made of aromatic diamine and a light emitting layer made of 8-hydroxyquinoline aluminum complex, (Appl. Phys. Lett., 51, 913, 1987) significantly improves luminous efficiency compared to conventional EL devices using single crystals such as anthracene. Has been made. Further, for example, by using an aluminum complex of 8-hydroxyquinoline as a host material and doping a fluorescent dye for laser such as coumarin (J. Appl. Phys., 65, 3610, 1989), luminous efficiency is improved. In addition, conversion of light emission wavelength and the like are also being performed, which is approaching practical characteristics.

  In addition to the electroluminescent device using the low molecular weight material as described above, as the material of the light emitting layer, poly (p-phenylene vinylene), poly [2-methoxy-5- (2-ethylhexyloxy) -1,4 Development of electroluminescent devices using polymer materials such as -phenylene vinylene] and poly (3-alkylthiophene), and devices that mix low molecular light emitting materials and electron transfer materials with polymers such as polyvinyl carbazole. Has been done.

  As an attempt to increase the luminous efficiency of the device, the use of phosphorescence instead of fluorescence has been studied. If phosphorescence is used, that is, light emission from a triplet excited state is used, an efficiency improvement of about three times is expected as compared with a conventional device using fluorescence (singlet). For this purpose, it has been studied to use a coumarin derivative or a benzophenone derivative as a light emitting layer (see Non-Patent Document 1), but only a very low luminance was obtained. Thereafter, the use of a europium complex has been studied as an attempt to utilize the triplet state, but this also did not lead to highly efficient light emission.

  Recently, it has been reported that highly efficient red light emission is possible by using the following platinum complex (T-1) (see Non-Patent Document 2). Then, the efficiency is greatly improved by further green light emission by doping the light emitting layer with the iridium complex (T-2) shown below (see Non-Patent Document 3).

In order to apply the organic electroluminescence device to a display device such as a flat panel display, it is necessary to improve the light emission efficiency of the device and at the same time to ensure sufficient stability during driving.
However, the organic electroluminescent element using the phosphorescent molecule (T-2) described in the above-mentioned document has high efficiency light emission, but has insufficient driving stability for practical use (see Non-Patent Document 4). Realization of a highly efficient display element is a difficult situation.
It is estimated that the main cause of the drive deterioration is due to deterioration of the light emitting layer.
The charge injected from the electrode becomes an electron-hole pair (exciton) with a certain probability. In general, light emission (phosphorescence) by triplet excitons has a longer lifetime than light emission (fluorescence) by singlet excitons. Conversely, thermal stability of singlet excitons is higher than that of triplet excitons. Is also expensive. Here, when the current applied to the element increases, the charge injected into the light emitting layer increases, and accordingly, the amount of charges that do not become excitons also increases. Further, among those that have become excitons, those that do not contribute to light emission in the light emitting layer and are thermally deactivated increase. For this reason, the temperature of the light emitting layer is increased, and in particular, triplet excitons are inferior in thermal stability to singlet excitons, so that the device is considered to deteriorate. This is also presumed from the fact that the luminous efficiency of the organic electroluminescent element using phosphorescent molecules (T-2) greatly decreases with the increase in injection current (see Non-Patent Document 3).

  Many of the organic electroluminescence devices using phosphorescent molecules developed so far are characterized by using a material containing a carbazolyl group as a host of the light emitting layer. For example, Non-Patent Document 3 uses the following biphenyl derivatives as host materials.

However, since the above (H-1) is very easy to crystallize and Tg is low, it is known that the stability of the film is poor, and the luminous efficiency as an element is not sufficiently satisfactory.
Patent Document 1 discloses a compound (H-2) shown below as a host material.

However, although the above compound is excellent in film forming property, it has a serious problem in terms of heat resistance.
Patent Document 2 suggests the following compounds and the like as materials for organic electroluminescent elements.

Although the synthesis and evaluation examples of these compounds are not specified, as far as the examples in the literature are concerned, such compounds emit light only under a high voltage, and the essential light emission luminance and light emission efficiency are completely absent. It was sufficient and far from practical use.
Non-Patent Document 5 discloses the following compound (H-3) as a novel fluorescent material, but the compound has extremely poor solubility and is extremely difficult to purify and characterize.

Further, in this document, for the purpose of improving the solubility of (H-3), a compound in which a total of 12 long-chain alkyl groups are introduced at the 3,6-positions of 6 N-carbazolyl groups (not shown) Have been disclosed and their specific photoexcited emission properties have been reported.
However, long-chain alkyl groups have large molecular motion, and a compound having many such groups is disadvantageous in terms of luminous efficiency as a light-emitting material. In addition, no study has been made on the electroluminescence characteristics of the compound.
For the reasons described above, in particular, organic electroluminescent devices using phosphorescent molecules have a serious problem in the heat resistance and luminous efficiency of the device for practical use, particularly in terms of the material.
Special table 2003-515897 gazette JP-A-6-1972 The 51st Japan Society of Applied Physics, 28a-PB-7, 1990 Nature, 395, 151, 1998 Appl. Phys. Lett., 75, 4, pp. 1999 Jpn. J. Appl. Phys., 38, L1502, 1999 Chemical Physics Letters, 289 (1998), 13-18

  As a result of intensive studies aimed at providing an organic electroluminescence device having high efficiency and high driving stability in view of the above situation, the present inventor has solved the above problem by using a specific compound particularly in the light emitting layer. The inventors have found that the problem can be solved and have completed the present invention.

As a result of intensive studies by the present inventors, it has been found that a compound having a certain skeleton can solve the above-mentioned problems, and has led to the present invention.
That is, the present invention resides in the organic electroluminescent device having a charge transport material comprising an organic compound represented by the following general formula (I), the organic electroluminescent element material, and a layer containing the compound.

（式中、Ｌ^１およびＬ^２は水素原子または、炭素数１〜６のアルキル基、炭素数１〜４のアルコキシ基、ハロゲン原子、炭素数２〜６のアルケニル基、炭素数１〜４のアルキル鎖を有するジアルキルアミノ基、炭素数１〜４のアルキルチオ基、およびフェニル基よりなる群から選ばれる置換基を表す。） (In the formula, ring A is a 5- or 6-membered monocyclic ring or an aromatic hydrocarbon ring composed of 2 to 5 condensed rings, or a 5- or 6-membered monocyclic ring or an aromatic heterocyclic ring composed of 2 to 4 condensed rings. N represents an integer of 3 or more.
The ring A has a —NR ¹ R ² group at three or more adjacent substitution positions, and one or more substitution positions are unsubstituted, or a linear or branched group having 1 to 8 carbon atoms. An alkyl group having 2 to 9 carbon atoms, an alkynyl group having 2 to 9 carbon atoms, an aralkyl group having 7 to 15 carbon atoms, and an alkyl group having 1 to 8 carbon atoms which may have a substituent. An alkylamino group having one or more, an arylamino group having an optionally substituted aromatic hydrocarbon group having 6 to 12 carbon atoms, an optionally substituted 5- or 6-membered aromatic ring A heteroarylamino group having a heterocyclic group, an acylamino group having an acyl group having 2 to 10 carbon atoms which may have a substituent, an alkoxy group having 1 to 8 carbon atoms which may have a substituent, Aryloxy group having an aromatic hydrocarbon group having 6 to 12 carbon atoms A heteroaryloxy group having a 5- or 6-membered aromatic ring group, an optionally substituted acyl group having 2 to 10 carbon atoms, and an optionally substituted substituent having 2 to 10 carbon atoms Alkoxycarbonyl group, optionally substituted aryloxycarbonyl group having 7 to 13 carbon atoms, alkylcarbonyloxy group having 2 to 10 carbon atoms, carboxyl group, cyano group, hydroxyl group, mercapto group, 1 to carbon atoms An alkylthio group having 8 carbon atoms, an arylthio group having 6 to 12 carbon atoms, a sulfonyl group which may have a substituent, a silyl group which may have a substituent, a boryl group which may have a substituent, In a group selected from the group consisting of an optionally substituted phosphino group, an optionally substituted aromatic hydrocarbon group and an optionally substituted aromatic heterocyclic group Has been replaced. Further, the n —NR ¹ R ² groups contained in one molecule may be the same or different. However, the —NR ¹ R ² group is a group represented by the following formula R-27. )

(In the formula, L ¹ and L ² are a hydrogen atom , an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, an alkenyl group having 2 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. It represents a substituent selected from the group consisting of a dialkylamino group having an alkyl chain, an alkylthio group having 1 to 4 carbon atoms, and a phenyl group .)

In the compound represented by formula (I), —NR ¹ R ² groups are successively bonded to three or more adjacent substitution positions on ring A. Three or more, more preferably four or more, and even more preferably five or more nitrogen atoms (-NR ¹ R ² groups) are continuously arranged at very close positions substantially in the same plane as ring A. As a result, excellent charge transportability and electrical redox durability are exhibited. In addition, when a hydrogen atom or a group different from the —NR ¹ R ² group is bonded to at least one or more substitution positions, the symmetry of the molecule is lowered and the solubility is improved.
In the present invention, the “substitution position” means a position where a hydrogen atom is bonded, that is, a substitutable position, assuming that the ring A is not substituted.

According to the light emitting layer of the organic electroluminescent element using the organic compound of the present invention, it is possible to emit light with high luminance and high efficiency at a low voltage, and further, the stability of the element is improved.
In addition, due to its excellent heat resistance, film-forming property, charge transportability, and light emission characteristics, it can be used in accordance with the layer structure of the device, light emitting material, hole injection material, hole transport material, electron injection material, electron transport material, hole It can also be applied as a blocking material, an electronic blocking material, or the like.
Therefore, the organic electroluminescent device according to the present invention is a flat panel display (for example, for OA computers and wall-mounted televisions), an in-vehicle display device, a light source utilizing characteristics of a mobile phone display or a surface light emitter (for example, a light source of a copying machine, It can be applied to liquid crystal displays and back light sources for instruments, display panels, and indicator lights, and its technical value is great.
The organic compound of the present invention is also useful for electrophotographic photoreceptors and the like because of its inherently excellent redox stability.

The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and is not specified by these contents.
The organic compound of the present invention is represented by the following general formula (I).

(In the formula, ring A represents an arbitrary aromatic ring, and n represents an integer of 3 or more.
The ring A has a —NR ¹ R ² group (provided that R ¹ and R ² each independently represents an arbitrary substituent, or are bonded to each other to have a substituent at three or more adjacent substitution positions. And one or more substitution positions are unsubstituted or substituted with an arbitrary group different from the —NR ¹ R ² group. Yes. Further, the n —NR ¹ R ² groups contained in one molecule may be the same or different. )
-NR ¹ N atom in R ² groups, and N atoms in addition to -NR ¹ R ² group present in the same molecule, electrical (including, electrostatic) positioned intramolecular interactions possible distance It is important that Preferably, the distance is approximately equal to or less than the sum of van der Waals radii of two nitrogen atoms. In addition, the ring A is deformed by being too close, the bond distance between the ring A and the —NR ¹ R ² group is extended, or the bond angle is remarkably changed. It is also important that the distance is some distance so as not to impair the repeated stability against redox. From this viewpoint, the N-N distance is preferably 1.5 angstroms or more, more preferably 2.0 angstroms or more, and further preferably 2.5 angstroms or more. Further, it is preferably 5.0 angstroms or less, more preferably 4.0 angstroms or less, and further preferably 3.5 angstroms or less.

The NN distance is a normal MM2 calculation method (for example, “J. Compute. Chem.” (16, 791-816 (1995)), co-authored by M. J. Dudek and J. W. Ponder. And the value calculated from the spatial position between the atoms obtained by deriving the most stable structure of the organic compound of the present invention.
The compound of the present invention has n —NR ¹ R ² groups in one molecule, and n is an integer of 3 or more. Preferably it is 10 or less, more preferably 8 or less, and most preferably 6 or less. Exceeding the upper limit is not preferable because film formation by vapor deposition is difficult, and it is difficult to increase the purity of the material due to an increase of by-products by synthesis and a decrease in solubility of the product.
Arbitrary groups can be applied as R ¹ and R ^{2 in} the present invention, and they may be the same or different from each other. To illustrate,
An alkyl group which may have a substituent (preferably a linear or branched alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, n-propyl, 2-propyl, n-butyl, isobutyl, tert, -Butyl group and the like).
An alkenyl group which may have a substituent (preferably an alkenyl group having 2 to 9 carbon atoms, such as vinyl, allyl, 1-butenyl group, etc.),

An alkynyl group which may have a substituent (preferably an alkynyl group having 2 to 9 carbon atoms, such as ethynyl and propargyl groups);
An aralkyl group which may have a substituent (preferably an aralkyl group having 7 to 15 carbon atoms, such as a benzyl group);
An acyl group which may have a substituent (preferably an acyl group having 2 to 10 carbon atoms which may have a substituent, for example, a formyl, acetyl, benzoyl group, etc.),

An alkoxycarbonyl group which may have a substituent (preferably an alkoxycarbonyl group having 2 to 10 carbon atoms which may have a substituent, including, for example, methoxycarbonyl and ethoxycarbonyl groups),
An aryloxycarbonyl group which may have a substituent (preferably an aryloxycarbonyl group having 7 to 13 carbon atoms which may have a substituent, such as a phenoxycarbonyl group);
An alkylcarbonyloxy group which may have a substituent (preferably an alkylcarbonyloxy group having 2 to 10 carbon atoms which may have a substituent, including, for example, an acetoxy group),
Carboxyl group,

An aromatic hydrocarbon group which may have a substituent (for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, etc. A monovalent group derived from a 5- or 6-membered monocyclic ring or a 2-5 condensed ring is included)
Or an aromatic heterocyclic group which may have a substituent (for example, furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, Pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring,
Furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, benzimidazole ring And monovalent groups derived from 5- or 6-membered monocyclic rings or 2-4 condensed rings such as perimidine ring, quinazoline ring, quinazolinone ring, and azulene ring).

Examples of the substituent that each of the above-described groups may have are described in the specific examples. For example, an alkyl group having about 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom (particularly a fluorine atom or chlorine). Atom), an alkenyl group having 2 to 6 carbon atoms, a dialkylamino group having an alkyl chain having 1 to 4 carbon atoms, an alkylthio group having 1 to 4 carbon atoms, and a phenyl group.
In the general formula (I), in addition to intramolecular interactions between N atoms occurring between a plurality of —NR ¹ R ² groups in the same molecule, R ^{1 to} each other, R ^{2 to} each other, or R ^{1 to} R ² R ¹ and R ² are aromatic hydrocarbons which may have a substituent from the viewpoint that an intramolecular interaction at the same temperature can be obtained, and an improvement in charge transportability and electrical redox durability can be obtained. An aromatic heterocyclic group which may have a group or a substituent is preferable, and an aromatic hydrocarbon group which may have a substituent is more preferable.
Among them, the following groups are particularly preferable, but are not limited thereto.

Among the above groups, R-1, R-2, R-3, and R-8 are more preferable from the viewpoint of having an appropriate redox potential difference, and R-1, R-2, and R-8 are more preferable. preferable.
On the other hand, in the organic compound of the present invention, from the viewpoint of improving the emission quantum efficiency by suppressing nonradiative deactivation (thermal deactivation) of excitons due to unnecessary molecular motion, the —NR ¹ R ² group is R ^1. And R ² are linked directly or via a linking group to form a ring (hereinafter referred to as cyclic —NR ¹ R ² group). In addition to the intramolecular interaction between N atoms, an intramolecular interaction between cyclic —NR ¹ R ² can be obtained, and the improvement in charge transportability and electrical redox durability can be achieved. More preferably, NR ¹ R ² has a π electron that can be conjugated with an unshared electron pair on the N atom contained in itself, and the group as a whole is an aromatic group (aromatic hydrocarbon group and aromatic group). A heterocyclic group is preferred.
As cyclic -NR ¹ R ² , more preferable cyclic groups from the above viewpoint are shown below, but are not limited thereto.

In each of the above structures, L ¹ and L ² represent a hydrogen atom or an arbitrary substituent represented by a group exemplified as a substituent that R ¹ and R ² may have. The cyclic -NR ¹ R ² group is L ¹
In addition to L ² , it may have an arbitrary substituent.
Among the above groups, R-14, R-15, R-16, R-21, R-22, R- from the viewpoint of having an appropriate redox potential difference and stability against electrical redox. 24, R-27, R-32, R-39, and R-40 are more preferable, R-14, R-16, R-21, R-22, R-27, and R-40 are more preferable. -14, R-27 is more preferred, and R-27 is most preferred.

Cyclic —NR ¹ R ² may have any substituent, for example
An alkyl group which may have a substituent (preferably a linear or branched alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, n-propyl, 2-propyl, n-butyl, isobutyl, tert, -Butyl group and the like).
An alkenyl group which may have a substituent (preferably an alkenyl group having 2 to 9 carbon atoms, such as vinyl, allyl, 1-butenyl group, etc.),
An alkynyl group which may have a substituent (preferably an alkynyl group having 2 to 9 carbon atoms, such as ethynyl and propargyl groups);
An aralkyl group which may have a substituent (preferably an aralkyl group having 7 to 15 carbon atoms, such as a benzyl group);
An amino group optionally having a substituent

[Preferably, an alkylamino group having one or more alkyl groups having 1 to 8 carbon atoms which may have a substituent (for example, methylamino, dimethylamino, diethylamino, dibenzylamino group, etc.),
An arylamino group having an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent (for example, phenylamino, diphenylamino, ditolylamino group, etc.);
A heteroarylamino group having a 5- or 6-membered aromatic heterocyclic group which may have a substituent (for example, pyridylamino, thienylamino, dithienylamino group, etc.);
An acylamino group having an acyl group having 2 to 10 carbon atoms which may have a substituent (for example, acetylamino, benzoylamino group and the like are included)],

An alkoxy group which may have a substituent (preferably an alkoxy group having 1 to 8 carbon atoms which may have a substituent, for example, a methoxy, ethoxy, butoxy group, etc.);
An aryloxy group which may have a substituent (preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2-naphthyloxy group, etc. ),
An optionally substituted heteroaryloxy group (preferably having a 5- or 6-membered aromatic heterocyclic group, including, for example, pyridyloxy, thienyloxy groups),
An acyl group which may have a substituent (preferably an acyl group having 2 to 10 carbon atoms which may have a substituent, for example, a formyl, acetyl, benzoyl group, etc.),

An alkoxycarbonyl group which may have a substituent (preferably an alkoxycarbonyl group having 2 to 10 carbon atoms which may have a substituent, including methoxycarbonyl, ethoxycarbonyl group, etc.), substituted An aryloxycarbonyl group which may have a group (preferably an aryloxycarbonyl group having 7 to 13 carbon atoms which may have a substituent, such as a phenoxycarbonyl group),
An alkylcarbonyloxy group which may have a substituent (preferably an alkylcarbonyloxy group having 2 to 10 carbon atoms which may have a substituent, including, for example, an acetoxy group),
Carboxyl group,
A cyano group,
Hydroxyl group,
Mercapto group,

An alkylthio group which may have a substituent (preferably an alkylthio group having 1 to 8 carbon atoms, including, for example, a methylthio group, an ethylthio group, etc.);
An arylthio group which may have a substituent (preferably an arylthio group having 6 to 12 carbon atoms, including, for example, a phenylthio group, a 1-naphthylthio group, etc.);
A sulfonyl group which may have a substituent (for example, mesyl group, tosyl group and the like are included),
A silyl group which may have a substituent (for example, a trimethylsilyl group, a triphenylsilyl group, etc.),
An optionally substituted boryl group (for example, a dimesitylboryl group),
Phosphino group which may have a substituent (for example, diphenylphosphino group and the like are included),
An aromatic hydrocarbon group which may have a substituent (for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, etc. A monovalent group derived from a 5- or 6-membered monocyclic ring or a 2-5 condensed ring is included)

  Or an aromatic heterocyclic group which may have a substituent (for example, furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, Pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring , Pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, sinoline ring, quinoxaline ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, etc. Environment Etc. include monovalent group).

Examples of the substituent that each of the above-described groups may have are described in the specific examples. For example, an alkyl group having about 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom (particularly a fluorine atom or chlorine). Atom), an alkenyl group having 2 to 6 carbon atoms, a dialkylamino group having an alkyl chain having 1 to 4 carbon atoms, an alkylthio group having 1 to 4 carbon atoms, and a phenyl group.
From the viewpoint of limiting molecular vibrations in the compound, the cyclic —NR ¹ R ² group in the general formula (I) is unsubstituted or has an alkyl group which may have a substituent, or a substituent. It may preferably have an aromatic hydrocarbon group (in particular, a hydrocarbon group having about 6 to 12 carbon atoms), particularly preferably unsubstituted or substituted with a methyl group or a phenyl group.

In the general formula (I), the ring A is substituted at one or more substitution positions with no substitution (a hydrogen atom is bonded) or with any group different from the —NR ¹ R ² group. ing. This is important from the viewpoint of improving the solubility of the compound (if the solubility is poor, there is no purification method other than sublimation purification, which causes a problem in increasing the purity of the compound) or charge transportability.
As "any group that is different from the -NR ¹ R ² group" satisfies the definition of the -NR ¹ R ² group, but three or more adjoining attached at the actual ring A -NR ¹ R it may be different groups, the ² groups, or may be a group which does not meet the definition of -NR ¹ R ² group. A group that does not satisfy the definition of the —NR ¹ R ² group is preferable. Examples of such groups include:

An alkyl group which may have a substituent (preferably a linear or branched alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, n-propyl, 2-propyl, n-butyl, isobutyl, tert, -Butyl group and the like).
An alkenyl group which may have a substituent (preferably an alkenyl group having 2 to 9 carbon atoms, such as vinyl, allyl, 1-butenyl group, etc.),
An alkynyl group which may have a substituent (preferably an alkynyl group having 2 to 9 carbon atoms, such as ethynyl and propargyl groups);
An aralkyl group which may have a substituent (preferably an aralkyl group having 7 to 15 carbon atoms, such as a benzyl group);

An amino group which may have a substituent [preferably, an alkylamino group having one or more alkyl groups having 1 to 8 carbon atoms which may have a substituent (for example, methylamino, dimethylamino, diethylamino, Dibenzylamino group, etc.),
An arylamino group having an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent (for example, phenylamino, diphenylamino, ditolylamino group, etc.);
A heteroarylamino group having a 5- or 6-membered aromatic heterocyclic group which may have a substituent (for example, pyridylamino, thienylamino, dithienylamino group, etc.);

An acylamino group having an acyl group having 2 to 10 carbon atoms which may have a substituent (for example, acetylamino, benzoylamino group and the like are included)],
An alkoxy group which may have a substituent (preferably an alkoxy group having 1 to 8 carbon atoms which may have a substituent, for example, a methoxy, ethoxy, butoxy group, etc.);
An aryloxy group which may have a substituent (preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, including, for example, phenyloxy, 1-naphthyloxy, 2-naphthyloxy group, etc. ),

An optionally substituted heteroaryloxy group (preferably having a 5- or 6-membered aromatic ring group, including, for example, a pyridyloxythienyloxy group),
An acyl group which may have a substituent (preferably an acyl group having 2 to 10 carbon atoms which may have a substituent, for example, a formyl, acetyl, benzoyl group, etc.),
An alkoxycarbonyl group which may have a substituent (preferably an alkoxycarbonyl group having 2 to 10 carbon atoms which may have a substituent, including, for example, methoxycarbonyl and ethoxycarbonyl groups),

An aryloxycarbonyl group which may have a substituent (preferably an aryloxycarbonyl group having 7 to 13 carbon atoms which may have a substituent, such as a phenoxycarbonyl group);
An alkylcarbonyloxy group which may have a substituent (preferably an alkylcarbonyloxy group having 2 to 10 carbon atoms, including, for example, an acetoxy group),
Carboxyl group,
A cyano group,
Hydroxyl group,
Mercapto group,

An alkylthio group which may have a substituent (preferably an alkylthio group having 1 to 8 carbon atoms, including, for example, a methylthio group, an ethylthio group, etc.);
An arylthio group which may have a substituent (preferably an arylthio group having 6 to 12 carbon atoms, including, for example, a phenylthio group, a 1-naphthylthio group, etc.);
A sulfonyl group which may have a substituent (for example, mesyl group, tosyl group and the like are included),
A silyl group which may have a substituent (for example, a trimethylsilyl group, a triphenylsilyl group, etc.),
An optionally substituted boryl group (for example, a dimesitylboryl group),
Phosphino group which may have a substituent (for example, diphenylphosphino group and the like are included),
An aromatic hydrocarbon group which may have a substituent (for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, etc. A monovalent group derived from a 5- or 6-membered monocyclic ring or a 2-5 condensed ring is included)

  Or an optionally substituted aromatic heterocyclic group (eg, furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrrolo) Imidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, A monovalent group derived from a 5- or 6-membered monocyclic ring or a 2-4 condensed ring such as a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a sinoline ring, a quinoxaline ring, a benzimidazole ring, a perimidine ring or a quinazoline ring Is included) It is mentioned as preferable examples.

In the general formula (I), the ring A is substituted at one or more substitution positions with no substitution (a hydrogen atom is bonded) or with any group different from the —NR ¹ R ² group. However, for the purpose of imparting a moderately wide redox potential to the compound, it is a hydrogen atom or a hydrocarbon group (an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group or an aromatic hydrocarbon group). preferable. Further, from the viewpoint of limiting molecular vibrations in the compound and from the viewpoint of imparting durability against electrical oxidation / reduction, the compound preferably has a hydrogen atom, an alkyl group which may have a substituent, or a substituent. An aromatic hydrocarbon group that may be present (in particular, an aromatic hydrocarbon group having about 6 to 12 carbon atoms) or an aromatic heterocyclic group that may have a substituent (such as a pyridyl group), particularly preferably. A hydrogen atom, a methyl group, a pyridyl group or a phenyl group is most preferred, and a pyridyl group or a phenyl group is most preferred.

From the viewpoint of suppressing molecular vibration and ensuring sublimation, the molecular weight of “an arbitrary group different from the —NR ¹ R ² group” should be small, specifically about 500 or less, preferably about 200 or less. Further preferred.
The molecular weight of the compound represented by the general formula (I) is usually preferably 4000 or less, more preferably 2500 or less, and still more preferably 1500 or less. Moreover, 200 or more are preferable, 300 or more are more preferable, and 400 or more are further more preferable. If the molecular weight exceeds the upper limit, the sublimation property is remarkably lowered, which may hinder the vapor deposition operation when producing the electroluminescent device, or it becomes difficult to purify to high purity due to the lower solubility in the solvent. If the molecular weight is less than the lower limit, the glass transition temperature, melting point, vaporization temperature, film-forming property, etc. will decrease, and heat resistance may be significantly impaired. There is sex.
Ring A in general formula (I) represents an aromatic ring.

Specifically, for example, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, a fluoranthene ring, etc. Or an aromatic hydrocarbon ring composed of 2 to 5 condensed rings;
Furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene Ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline Examples thereof include aromatic heterocycles composed of a 5- or 6-membered monocyclic ring or a 2-4 condensed ring such as a ring, a benzimidazole ring, a perimidine ring, and a quinazoline ring.
Preferred examples in the case where ring A is a single ring are given below, but the present invention is not limited thereto.

  Moreover, although the preferable example in case the ring A is a condensed ring is given below, this invention is not necessarily limited to these.

Ring A is represented by the following formula (I ′) as “an arbitrary group different from the —NR ¹ R ² group”.

で表される基を有し、一化合物中に本発明の特徴的構造を２以上有していても良い。このような化合物の例としては、例えば下記化合物が挙げられるが、これに限定されない。

And one compound may have two or more characteristic structures of the present invention. Examples of such compounds include, but are not limited to, the following compounds.

In the above exemplary compounds A-1 to A-38, R ^{41 to} R ⁵⁰ are each independently a hydrogen atom, or any group typified by the group listed above as the group that Ring A may have. To express.
In formula A-36, Z represents a direct bond or a divalent linking group. Examples of the divalent linking group include an alkane group (including a perfluoroalkane group) that may have a substituent,
An alkene group which may have a substituent,
An alkyne group which may have a substituent,
—NR ^a — (wherein R ^a is an optional substituent), —O—, —CO—, —COO—, —SO—, —SO ₂ —
An amide group which may have a substituent,
A silyl group which may have a substituent,
An optionally substituted boryl group,
A phosphino group which may have a substituent,
An aromatic hydrocarbon group which may have a substituent,
Or the aromatic heterocyclic group etc. which may have a substituent are mentioned.
Specific examples of each include the divalent group corresponding to the monovalent group described above as an example of the arbitrary group that the ring A may have. The same group as what a group may have is mentioned.
In addition, as R ^a , the same groups as those listed above can be given as examples of arbitrary groups that ring A may have.
Particularly preferred examples of the linking group Z are described below.

Among the above specific examples relating to ring A, A-1, A-2, A-3, A-4, A-5, from the viewpoint of having an appropriate redox potential difference and stability against electrical redox. A-8, A-9, A-10, A-11, A-16, A-17, A-18, A-19, A-20, A-21, A-22, A-23, A- 24, A-25, A-28, A-29, A-30, A-31, A-32, A-33, A-34, A-35, A-36, A-37, A-38 More preferably, A-1, A-5, A-9, A-10, A-11, A-17, A-18, A-22, A-24, A-28, A-32, A-35. , A-36, and A-38 are more preferable, and A-1 and A-5 are most preferable.
Among the compounds represented by the general formula (I), the point having a wide redox potential difference, the point of stability against electrical redox, the point of increasing triplet excited state energy, and the solubility are improved, From the viewpoint of facilitating coating film formation by a wet method and facilitating high-purity purification of the compound, compounds represented by the following general formula (II) or the following general formula (III) are preferred.

Wherein (II), X ¹ ~X ⁵ represents -NR ¹ R ² group. The —NR ¹ R ² group has the same meaning as in the general formula (I). X ^{1 to} X ⁵ may be the same or different from each other. A ⁰ is —NR ¹ R ²
An arbitrary substituent different from the group is represented.

In formula (III), Y ^{1 to} Y ⁵ represent a —NR ¹ R ² group. The —NR ¹ R ² group has the same meaning as in the general formula (I). Y ^{1 to} Y ⁵ may be the same or different from each other.
Preferred specific examples of the compound represented by the general formula (I) are shown below, but the present invention is not limited thereto. In the table, Ph represents an unsubstituted phenyl group.

It can synthesize | combine using the well-known method represented with the said general formula (I).
For example, in the ring A, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, a silyl group such as a trimethylsilyl group, a hydrogen atom, or the like at a substitution position where a —NR ¹ R ² group or other substituent is to be introduced. In the case of synthesizing using a ring A precursor having a -NR ¹ R ² group can be introduced by reacting the ring A precursor with H-NR ¹ R ² or a derivative thereof. Moreover, arbitrary substituents can be introduced by reacting a derivative corresponding to the substituent to be introduced.
When synthesizing using a ring A precursor having a —NH ₂ group, a —NHR ¹ group, or a derivative thereof at a substitution position where a —NR ¹ R ² group is to be introduced, the ring A precursor is converted to X—R ¹ and X
By reacting with —R ² (X is a halogen atom or the like), a —NR ¹ R ² group can be introduced.

  As these reaction methods, for example, Ullman method using a base such as 0 to 2 valent copper catalysts such as Cu, CuO and CuI, sodium carbonate and potassium carbonate (the solvent includes, for example, no solvent, glycerin, etc. Strong base method using sodium hydride, tert-butoxypotassium, triethylamine, LDA (lithium diisopropylamine), n-BuLi, etc. (as solvents, for example, THF, 1,4-dioxane, diethyl ether, DMF , DMA, etc. can be used) ・ Substitution of the halogen element on ring A with boron, in the presence of a base such as potassium phosphate, sodium carbonate, cesium carbonate, silver carbonate, tetrakis (triphenylphosphine) palladium, etc. Suzuki coupling method using palladium catalyst (as solvent For example, toluene, ethanol, water can be used),

Exchange ligands such as divalent palladium complexes such as palladium acetate, tri (tert-butyl) phosphine, triphenylphosphine, dppf (1,1′-bis (diphenylphosphino) ferrocene) as necessary, Palladium method in which a strong base such as tert-butoxy sodium or silver carbonate is used for reaction (for example, DMF or DMA can be used as a solvent), a divalent copper catalyst such as copper acetate, a base such as triethylamine, and the like Depending on the divalent copper catalyst method in which the reaction is carried out in the presence of a dehydrating agent such as molecular sieves (for example, dichloromethane can be used as a solvent),
Photoreaction method that reacts by irradiating light using a mercury lamp, etc.,
An ultrasonic method of reacting by irradiating ultrasonic waves,
An electron beam method in which an electron beam is irradiated and reacted using a microwave oven,
A high-temperature method of reacting by applying high heat of 300 ° C. or higher,
Tin catalyst method using tin chloride,
Lewis acid method using aluminum chloride, titanium tetrachloride, trifluoroboron, etc.
Strong acid method using phosphorus oxychloride, polyphosphoric acid, sulfuric acid,
What is necessary is just to select suitably according to the kind of compound from various well-known reactions, such as the lead method using lead acetate.

More preferably, a ring A precursor having a fluorine atom at a substitution position to which -NR ¹ R ² group or other substituent is to be introduced in ring A, sodium hydride, tert-butoxypotassium, triethylamine, This is a case of synthesis by a strong base method using LDA, n-BuLi or the like. This is because the reaction between a compound having three or more fluorine atoms on the same aromatic ring and an anionic secondary amine that has undergone hydrogen abstraction by a strong base proceeds radically, so the reaction is completed in a short time. The molecule in which the substitution reaction has started (in this case, the precursor molecule that should become ring A) is preferentially substituted over the unreacted molecule (the unreacted precursor molecule that should become ring A). Therefore, in spite of the multi-substitution reaction, the yield of by-products is very small. Even if the F-substituted product remains, the sublimation property is much better than the target product containing no F. Therefore, it has many advantages such as being easily removable by sublimation purification.
An example of a synthesis scheme of the compound represented by the general formula (I) having two kinds of —NR ¹ R ² groups in one molecule is shown below.

Since the compound represented by the general formula (I) has an appropriate charge transporting property, it is suitable as an electrophotographic photosensitive member, an organic electroluminescent device, a photoelectric conversion device, an organic solar cell, an organic rectifying device, etc. as a charge transporting material. Can be used for
In addition, since it is difficult to crystallize and has a high glass transition temperature, it has excellent thin film formability. Therefore, it is possible to provide an organic electroluminescent device that has excellent heat resistance and can be stably driven (emitted) for a long period of time. Suitable as a material.
Then, the organic electroluminescent element using the compound of this invention is demonstrated.
The organic electroluminescent device of the present invention has an anode, a cathode, and a light emitting layer provided between both electrodes, and the general electroluminescent element as the light emitting layer or as a layer between the light emitting layer and the anode or cathode. It has the layer containing the compound represented by Formula (I), It is characterized by the above-mentioned.

When the compound represented by the general formula (I) is contained in a hole transporting layer provided between the light emitting layer and the anode, the compound has a moderately low oxidation potential and a moderately high reduction potential. In particular, since it is necessary to be stable even in repeated electric oxidation, it is preferable that R ¹ and R ² in the —NR ¹ R ² group are not linked (for example, a diarylamino group). . More preferable examples include R-1, R-2, R-3, and R-8 among the structures listed above as specific examples, and R-1, R-2, and R-8 are more preferable.
In addition, when contained in an electron transporting layer provided between the light emitting layer and the cathode, it is desirable to have a moderately high oxidation potential and a moderately low reduction potential, especially for repeated electrical reduction. Need to be stable. Thus, R ¹ and R ² in the -NR ¹ R ² groups, cyclic -NR ¹ R ² group is desirable comprising linked directly or through a linking group, it contains many among them N atoms or fused ring group structure in It is more preferable that Preferable examples include, for example, R-14, R-15, R-20, R-21, R-24, R-25, R-26, R-27, R-28 among the structures listed above as specific examples. , R-29, R-30, R-31, R-32, R-33, R-34, R-35, R-36, R-37, R-40, R-41, R-42, R -43, R-44, R-45, R-46, etc., and R-14, R-15, R-20, R-21, R-24, R-27, R-28, R-32 , R-34, and R-40 are more preferable.

Furthermore, when it is contained in the light-emitting layer, particularly as a host material, it is desirable to have a moderately high oxidation potential and a moderately high reduction potential. Sex is necessary. Thus, R ¹ and R ² in the -NR ¹ R ² groups, cyclic -NR ¹ R ² group is desirable comprising linked directly or through a linking group, further comprises an aromatic heterocyclic fused ring group More preferable is a structure containing a moderate amount of. As a preferable example,
For example, among the structures listed above as specific examples, R-14, R-15, R-16, R-21, R-22, R-24, R-27, R-32, R-39, R-40, etc. R-14, R-16, R-21, R-22, R-27, R-39, R-40 are more preferable, R-14, R-27 are more preferable, and R-27 is Most preferred.

In the present invention, the compound represented by the general formula (I) is excellent in both hole transportability and electron transportability, has a good balance between both, and further has a high triplet exciton energy level. For this reason, when it is used as a light emitting layer material, particularly as a host material, it is preferable because the advantages are most utilized.
In the organic electroluminescent element of the present invention, two or more compounds represented by the general formula (I) may be contained in the same layer. When the compound represented by the general formula (I) is contained in two or more layers, the compounds contained in these layers may be the same or different.
In the organic electroluminescence device of the present invention, the cathode-light emitting layer is referred to as an “electron transport layer”, and in the case of two or more layers, the layer in contact with the cathode is referred to as an “electron injection layer”, and the other layers are collectively referred to. This is referred to as an “electron transport layer”. Of the layers provided between the cathode and the light emitting layer, the layer in contact with the light emitting layer may be particularly referred to as a “hole blocking layer”.
Hereinafter, with reference to the attached drawings, embodiments of the organic electroluminescent device of the present invention will be described in detail by taking as an example the case where the compound represented by the general formula (I) is contained in a light emitting layer.

FIG. 1 is a cross-sectional view schematically showing a structural example of a general organic electroluminescence device used in the present invention. 1 is a substrate, 2 is an anode, 4 is a hole transport layer, 5 is a light emitting layer, and 6 is a light emitting layer. A hole blocking layer, 8 represents a cathode.
The substrate 1 serves as a support for the organic electroluminescent element, 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 made of metal such as aluminum, gold, silver, nickel, palladium, platinum, metal oxide such as oxide of indium and / or tin, 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.
Hereinafter, it is 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 high, the stability is high, and impurities that become traps are less likely to be generated during manufacturing and 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.

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.
In the element shown in FIG. 1, a light emitting layer 5 is provided on the hole transport layer 4. The light emitting layer 5 is excited by recombination of holes injected from the anode and moving through the hole transport layer and electrons injected from the cathode and moved through the hole blocking layer 6 between the electrodes to which an electric field is applied. And formed from a compound that exhibits strong luminescence.
The compound used for the light emitting layer 5 is a compound that has a stable thin film shape, exhibits a high emission (fluorescence or phosphorescence) quantum yield in a solid state, and can efficiently transport holes and / or electrons. It is necessary to be. Further, it is required to be a compound that is electrochemically and chemically stable and does not easily generate impurities as traps during production or use.

Since the compound represented by the general formula (I) satisfies such a condition, it is preferably used as a light emitting layer material in an organic electroluminescent element. The light emitting layer 5 may be a layer made of only the compound, but is preferably a layer containing a light emitting material (dopant) for various purposes described below.
For the purpose of improving the light emission efficiency of the device and changing the emission color, for example, doping a fluorescent dye for laser such as coumarin with an aluminum complex of 8-hydroxyquinoline as a host material (J. Appl. Phys., Volume 65). , 3610, 1989) and the like, and it is preferable to dope a fluorescent dye also to the light emitting layer in the organic electroluminescent device of the present invention.
As a doping material, various fluorescent dyes can be used in addition to coumarin. Examples of fluorescent dyes that emit blue light include perylene, pyrene, anthracene, coumarin, and derivatives thereof. Examples of the green fluorescent dye include quinacridone derivatives and coumarin derivatives. Examples of yellow fluorescent dyes include rubrene and perimidone derivatives. Examples of red fluorescent dyes include DCM compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene and the like.

Other than the above-mentioned fluorescent dyes for doping, depending on the host material, listed in Laser Research, 8, 694, 803, 958 (1980); 9, 9, 85 (1981). Fluorescent dyes and the like that can be used as a doping material for the light emitting layer.
The amount of the fluorescent dye doped with respect to the host material is preferably 10 ⁻³ wt% or more, and more preferably 0.1 wt%. Moreover, 10 weight% or less is preferable and 3 weight% or less is more preferable. 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, leading to a reduction in luminous efficiency.

On the other hand, a light-emitting layer that emits phosphorescence is usually formed including a phosphorescent dopant and a host material. Examples of the phosphorescent dopant include organometallic complexes containing a metal selected from Groups 7 to 11 of the periodic table, and charge transporting organic compounds having a T1 higher than the T1 (lowest excited triplet level) of the metal complex. It is preferable to use it as a host material. The compound represented by the general formula (I) can be suitably used as a host material in the light emitting layer exhibiting phosphorescence emission.
Preferred examples of the metal in the phosphorescent organometallic complex containing a metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. As these organometallic complexes, compounds represented by the following general formula (i) or general formula (ii) are preferable.

（式中、Ｍは金属、ｐは該金属の価数を表す。ＬおよびＬ’は二座配位子を表す。ｊは０または１または２を表す。）

(In the formula, M represents a metal, p represents a valence of the metal, L and L ′ represent a bidentate ligand, and j represents 0, 1 or 2.)

(Wherein M ⁷ represents a metal, T represents carbon or nitrogen. When T is nitrogen, there is no R ¹⁴ or R ¹⁵ , and when T is carbon, R ¹⁴ or R ¹⁵ represents a hydrogen atom, a halogen atom, or an alkyl. Group, aralkyl group, alkenyl group, cyano group, amino group, acyl group, alkoxycarbonyl group, carboxyl group, alkoxy group, alkylamino group, aralkylamino group, haloalkyl group, hydroxyl group, aryloxy group, substituent Represents an aromatic hydrocarbon group or an aromatic heterocyclic group.
R ¹² and R ¹³ are hydrogen atom, halogen atom, alkyl group, aralkyl group, alkenyl group, cyano group, amino group, acyl group, alkoxycarbonyl group, carboxyl group, alkoxy group, alkylamino group, aralkylamino group, haloalkyl group , A hydroxyl group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent, and may be linked to each other to form a ring. )
In the general formula (i), the bidentate ligands L and L ′ each represent a ligand having the following partial structure.

(Ring A1 and Ring A1 ′ each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group, which may have a substituent. Ring A2 and Ring A2 ′ are nitrogen-containing aromatic heterocyclic groups. R ′, R ″, and R ′ ″ each represent a halogen atom; an alkyl group; an alkenyl group; an alkoxycarbonyl group; a methoxy group; an alkoxy group; an aryloxy group; (Amino group; diarylamino group; carbazolyl group; acyl group; haloalkyl group or cyano group)
More preferred examples of the compound represented by the general formula (i) include compounds represented by the following general formulas (ia), (ib) (ic).

(Wherein M ⁴ represents a metal, p represents a valence of the metal, ring A 1 represents an aromatic hydrocarbon group which may have a substituent, and ring A 2 may have a substituent. Represents a good nitrogen-containing aromatic heterocyclic group.)

(Wherein M ⁵ represents a metal, p represents a valence of the metal, ring A 1 represents an aromatic hydrocarbon group or aromatic heterocyclic group which may have a substituent, and ring A 2 represents a substituent. Represents a nitrogen-containing aromatic heterocyclic group which may have

(Wherein M ⁶ is a metal, p is a valence of the metal, and j is 0, 1 or 2. Ring A
1 and ring A1 ′ each independently represent an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group, and ring A2 and ring A2 ′ each independently have a substituent. A nitrogen-containing aromatic heterocyclic group which may be )
As the ring A1 and ring A1 of the compounds represented by the general formulas (ia), (ib), and (ic), a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, a thienyl group, a furyl group, a benzothienyl group are preferable. , Benzofuryl group, pyridyl group, quinolyl group, isoquinolyl group,
Or a carbazolyl group is mentioned.
Ring A2 and ring A2 ′ are preferably a pyridyl group, pyrimidyl group, pyrazyl group, triazyl group, benzothiazole group, benzoxazole group, benzimidazole group, quinolyl group, isoquinolyl group, quinoxalyl group, or phenanthridyl group. Can be mentioned.

Examples of the substituent that the compounds represented by the general formulas (ia), (ib) and (ic) may have include a halogen atom such as a fluorine atom; a C 1-6 carbon atom such as a methyl group and an ethyl group An alkyl 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; 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 and a diethylamino group; a diarylamino group such as a diphenylamino group; a carbazolyl group; an acyl group such as an acetyl group; A haloalkyl group; a cyano group, and the like, which may be linked to each other to form a ring.
In addition, the substituent which ring A1 and the substituent which ring A2 has may combine, or the substituent which ring A1 'and the substituent which ring A2' may combine may form one condensed ring, Examples of such a condensed ring include a 7,8-benzoquinoline group.
As the substituent for ring A1, ring A1 ′, ring A2 and ring A2 ′, an alkyl group, an alkoxy group, an aromatic hydrocarbon group, a cyano group, a halogen atom, a haloalkyl group, a diarylamino group, or a carbazolyl group is more preferable. Can be mentioned.
M ⁴ to M ⁵ in the formulas (ia) and (ib) are preferably ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold.
M ⁷ in formula (ii) is preferably ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold, and particularly preferably a divalent metal such as platinum or palladium.
Specific examples of the organometallic complexes represented by the general formulas (i), (ia), (ib) and (ic) are shown below, but are not limited to the following compounds.

  Specific examples of the organometallic complex represented by the general formula (ii) are shown below, but are not limited to the following compounds. In the formula, Me represents a methyl group, and Et represents an ethyl group.

Furthermore, the light emitting layer containing the compound represented by the general formula (I) may contain the above-described fluorescent dye together with the phosphorescent dopant.
The amount of the organometallic complex contained as a dopant in the light emitting layer is preferably 0.1% by weight or more, and more preferably 30% by weight or less. 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 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.
For example, a metal complex such as an aluminum complex of 8-hydroxyquinoline (JP 59-194393 A), a metal complex of 10-hydroxybenzo [h] quinoline (JP 6-322362 A), a bisstyrylbenzene derivative ( JP-A-1-245087 and JP-A-2-222484), bisstyrylarylene derivatives (JP-A-2-247278), metal complexes of (2-hydroxyphenyl) benzothiazole (JP-A-8-315983) , A light emitting layer material that emits fluorescence such as silole derivatives, carbazole derivatives such as 4,4′-N, N′-dicarbazolebiphenyl (WO 00/70655), tris (8-hydroxyquinoline) aluminum (USP) 6,303,238), 2,2 ′, 2 ″-(1,3,5- Luminescent layer that generates phosphorescence such as benzenetolyl) tris [1-phenyl-1H-benzimidazole] (Appl. Phys. Lett., 78, 1622, 2001), polyvinylcarbazole (Japanese Patent Laid-Open No. 2001-257076), etc. It may contain materials.

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 0.1 eV or more larger 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 a 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,

で定義される。（“Ｍｏｌｅｃｕｌａｒ Ｓｅｍｉｃｏｎｄｕｃｔｏｒｓ”，Ｓｐｒｉｎｇｅｒ−Ｖｅｒｌａ
ｇ，１９８５年、９８頁）。

Defined by ("Molecular Semiconductors", Springer-Verla
g, 1985, page 98).

  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.

従って、本発明で用いられる正孔阻止層は、酸化電位と還元電位をもちいて、（正孔阻止材料の酸化電位）−（発光材料の酸化電位）≧０．１Ｖ（正孔阻止材料の還元電位）≧（発光材料の還元電位）と表現することも出来る。
さらに後述の電子輸送層を有する素子の場合には、正孔阻止層の電子親和力は電子輸送層の電子親和力と比較して同等以下であることが好ましい。
（電子輸送材料の還元電位）≧（正孔阻止材料の還元電位）≧（発光材料の還元電位）
このような条件を満たす正孔阻止材料として、好ましくは、下記一般式（VII）で表わ
される混合配位子錯体が挙げられる。

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 ring group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and Z ³ represents silicon or germanium. Represents.)
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; A C2-C6 alkoxycarbonyl group such as a carbonyl group or an ethoxycarbonyl group; a carboxyl group; an aryloxy group such as a phenoxy group or a benzyloxy group; a dialkylamino group such as a diethylamino group or 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 ring group such as a phenyl group or naphthyl group which may have an aromatic group; an aromatic heterocyclic group such as a thienyl group or a pyridyl group which may have a substituent.

Examples of the substituent that the aromatic hydrocarbon ring 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 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 A dialkylamino group such as a dimethylamino group and a diethylamino group; an acyl group such as an acetyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group 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 ring group such as phenyl group, biphenyl group, naphthyl group or the like which may have a substituent, thienyl group, pyridyl group Represents an aromatic heterocyclic group such as
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.

  Further, as the hole blocking material, a compound having at least one pyridine ring substituted at the 2,4,6-position represented by the following structural formula can also be used.

(In the formula, R ⁹¹ , R ⁹² and R ⁹³ each independently represents a hydrogen atom or an arbitrary substituent. The linking group Q represents an n′-valent linking group, and the pyridine ring and the linking group Q are pyridine rings. Directly bonded to any one of positions 2 to 6. n ′ is an integer of 1 to 8.)
Specific examples of the compound having at least one pyridine ring substituted at the 2,4,6-position represented by the above structural formula are shown below, but are not limited thereto.

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 transporting 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, a uniform thin film can be formed with good contact with the anode, and it is 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, phthalocyanine compounds such as copper phthalocyanine (Japanese Patent Laid-Open No. 63-295695), polyaniline (Appl. Phys. Lett., 64, 1245, 1994), polythiophene (Optical Materials, 9, 125, 1998), etc., sputtered carbon films (Synth. Met., 91, 73, 1997), metals such as vanadium oxide, ruthenium oxide, molybdenum oxide Oxides (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.
In the case of the anode buffer layer, 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. The lower limit of the 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.

As described above, the organic electroluminescent element of the present invention has been described by taking as an example the layer structure containing the compound represented by the general formula (I) in the light emitting layer. The compound to be formed may be contained in an arbitrary layer provided between the light emitting layer and the cathode or the anode, and the light emitting layer in that case is selected from the compounds represented by the general formula (I) Even if it is a thing, it may consist of other materials.
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 present invention, by using the compound represented by the general formula (I), it is possible to obtain an organic electroluminescence device having excellent driving stability, long driving life, high light emission efficiency and low driving voltage. it can.

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)

480 mg of 2- (2,4-difluorophenyl) pyridine and 489 mg of trisacetylacetonatoiridium were added to 20 mL of glycerol subjected to nitrogen flow at 120 ° C. for 30 minutes, and stirred at 210 ° C. for 7 hours. After cooling to room temperature, 20 mL of methanol and 20 mL of water were added, and the deposited precipitate was filtered.
The obtained precipitate was purified by column chromatography (developing solvent was dichloromethane) and then sublimation purified to obtain 190 mg of a pale yellow solid. As a result of mass spectrum analysis of the obtained compound, it was confirmed that it was the target compound 1.
According to this synthesis example, compound 1 was obtained as a mixture of facial and meridional isomers, and defluorinated compounds 2, 3, and 4 were also included.
(Example 1)

Under a nitrogen atmosphere, a solution of carbazole (9.2 g) in anhydrous DMF (50 ml) was added over 20 minutes to a suspension of sodium hydride (55%, 2.4 g) in anhydrous DMF (N, N-dimethylformamide) (40 ml). After stirring at room temperature for 30 minutes and at 50 ° C. for 50 minutes, a DMF (10 ml) solution of 1,2,3,4,5-pentafluoropyridine (1.7 g) was added dropwise over 10 minutes, The mixture was stirred at room temperature for 40 minutes and at 80 ° C. for 70 minutes. The obtained solution was dropped into water (200 ml), and the deposited precipitate was filtered and washed with water (20 ml) and ethanol (3 × 50 ml). The obtained solid was extracted with chloroform and purified by recrystallization from chloroform-ethanol to obtain Target 1 (3.5 g). This compound had a glass transition temperature of 216 ° C., a vaporization temperature of 476 ° C., and a melting point of 449 ° C.
¹ H-NMR (270 MHz, CDCl ₃ ), 7.76 (d, 4H), 7.48 (d, 4H), 7.40 (d, 4H), 7.35 (d, 2H), 7.44 (t, 4H), 6.94-6.74 ( m, 16H), 6.60 (t, 4H), 6.52 (t, 2H)
DEI-MS m / z = 904 (M ⁺ ) (Example 2)

Under a nitrogen atmosphere, a solution of carbazole (9.2 g) in anhydrous DMF (80 ml) was added to an anhydrous DMF (N, N-dimethylformamide) (80 ml) suspension of sodium hydride (55%, 2.4 g) over 15 minutes. After stirring at 50 ° C. for 45 minutes, 1,2,3,4,5-pentafluorotoluene (1.8 g) was added dropwise in an ice bath, and 10 minutes in an ice bath at 15 ° C. for 15 minutes. The mixture was stirred at 80 ° C. for 25 minutes, 100 ° C. for 15 minutes, 120 ° C. for 40 minutes, and heated under reflux for 3 hours. After cooling to room temperature, the precipitate was separated by filtration, washed with methanol, dispersed in water (200 ml) and then washed with boiling to obtain the desired product 2 (6.6 g). In addition, the precipitate deposited from the mixture of the previous filtrate (DMF solution) and the washing solution (methanol solution) was filtered, dispersed in water (200 ml), washed by boiling, and the target product 2 (2.1 g) was obtained. . The vaporization temperature of this compound was 512 ° C., and the melting point was 448 ° C.
¹ H-NMR (270 MHz, CDCl ₃ ), 7.75 (dd, 4H), 7.33-7.27 (m, 8H), 7.18 (dd, 8H), 7.12-7.03 (m, 8H), 6.75-6.61 (m, 12H ), 2.04 (s, 3H)
DEI-MS m / z = 917 (M ⁺ ) (Example 3)

Under a nitrogen atmosphere, a solution of carbazole (8.0 g) in anhydrous DMF (80 ml) was added over 20 minutes to a suspension of sodium hydride (55%, 2.1 g) in anhydrous DMF (N, N-dimethylformamide) (70 ml). After stirring at 50 ° C. for 70 minutes, 1,2,3,5-hexafluorobenzene (1.5 g) was added dropwise, and at 70 ° C. for 100 minutes, 90 ° C. for 15 minutes, and 120 ° C. for 80 minutes. The mixture was stirred for 4.5 hours under heating to reflux. After cooling this to room temperature, water (70 ml) and methanol (30 ml) were added and stirred well, then the precipitate was filtered off, washed with water and methanol, and extracted with chloroform-toluene. The extract was purified by column and then purified by recrystallization from chloroform-ethanol to obtain the desired product 3 (5.5 g). This compound had a melting point of 448 ° C. and a boiling point of 478 ° C.
¹ H-NMR (270 MHz, CDCl ₃ ), 8.22 (s, 2H), 8.18 (d, 2H), 7.80-7.75 (m, 6H), 7.49 (t, 2H), 7.42-7.29 (m, 8H), 7.09-7.01 (m, 10H), 6.80 (t, 2H), 6.69 (t, 2H)
DEI-MS m / z = 738 (M ⁺ )

Example 4

Under a nitrogen atmosphere, a mixed solution of pentafluoroaniline (0.74 g), 1,2-dibenzoylethane (1.05 g), p-toluenesulfonic acid monohydrate (0.23 g), and toluene (25 ml) The mixture was stirred for 6 hours under reflux. After cooling this to room temperature, water (100 ml) and toluene (100 ml) were added and stirred well, then the organic layer was separated, dried over anhydrous magnesium sulfate, filtered and concentrated, and the resulting mixture was purified by silica gel. Purification by column chromatography gave the target product 4 (1.19 g).
EI-MS m / z = 385 (M +)
Under a nitrogen atmosphere, carbazole (2.60 g) was added to an anhydrous N, N-dimethylformamide (100 ml) suspension of sodium hydride (55%, 0.68 g) over 10 minutes, and the mixture was stirred at 60 ° C. for 20 minutes. After that, the target product 4 (1.0 g) was added under ice-cooling conditions, and the mixture was stirred for 5 hours under heating to reflux. After cooling to room temperature, ethyl acetate (10 ml), water (20 ml) and ethanol (20 ml) were added and stirred well. The deposited precipitate was separated by filtration, washed with ethanol, extracted from the remaining residue in chloroform (300 ml) under heating and reflux conditions, and the obtained extract was concentrated and then added in tetrahydrofuran (100 ml) -chloroform (100 ml). Then, suspension washing was performed in chloroform (100 ml) with heating under reflux to obtain the intended product 5 (0.40 g). This compound had a melting point of 340 ° C. and a boiling point of 571 ° C.
MALDI-TOF-MS m / z = 1120.77 (M +)

(Example 5)

Under a nitrogen atmosphere, carbazole (12.0 g) was added to an anhydrous N, N-dimethylformamide (200 ml) suspension of sodium hydride (55%, 3.13 g) over 10 minutes, and the mixture was stirred at 80 ° C. for 50 minutes. Then, 2,3,4,5,6-pentafluorobiphenyl (2.5 g) was added, and the mixture was stirred at 80 ° C. for 30 minutes and heated under reflux for 5 hours. After cooling to room temperature, the precipitate was filtered off and washed with methanol. The residue was stirred and washed with chloroform (200 ml) -monochlorobenzene (150 ml) under heating and reflux conditions. The remaining residue was extracted in monochlorobenzene (300 ml) under heating and reflux conditions, and the resulting extract was concentrated and then suspended and washed in methanol to obtain the desired product 6 (1.5 g). The melting point of this compound was not observed, the glass transition temperature was 301 ° C., and the vaporization temperature was 526 ° C.
DEI-MS m / z = 979 (M +)

(Example 6)

In a nitrogen stream and in an ice bath, a solution of diphenylamine (1.69 g) in anhydrous tetrahydrofuran (32 ml) was added to a normal hexane solution of normal butyl lithium (1.6 M, 6.2).
5 ml) was added dropwise and stirred at room temperature for 1 hour. The obtained solution was added dropwise over 34 minutes to a solution of pentafluoropyridine (10.0 ml) in anhydrous tetrahydrofuran (70 ml) under nitrogen cooling in a nitrogen stream and stirred for 5.8 hours. To the resulting solution was added 50 ml of brine, extracted with methylene chloride (150 ml), dried (anhydrous magnesium sulfate), filtered and concentrated. The obtained solid was purified by suspension washing in methanol (40 ml) to obtain the desired product 7 (1.56 g).
EI-MS, m / z = 318 (M +)
Carbazole (4.09 g) was added to a suspension of sodium hydride (55%, 1.07 g) in anhydrous N, N-dimethylformamide (50 ml) in a nitrogen stream and stirred at 80 ° C. for 35 minutes. Product 7 (1.56 g) was added, and the mixture was stirred with heating under reflux for 5.5 hours. After cooling to room temperature, 10 ml of water and 20 ml of methanol were added, and the precipitate was filtered off. The obtained solid was extracted with chloroform and purified by reprecipitation from chloroform-methanol to obtain the desired product 8 (4.25 g). The glass transition temperature of this compound was not detected, the melting point was 420 ° C., and the vaporization temperature was 472 ° C.
DEI-MS m / z = 906 (M +)

(Example 7)
Thin films of the compounds (target products 1 and 2) obtained in Examples 1 and 2 were each formed on a glass substrate by vacuum deposition. The obtained thin films were all transparent amorphous films, and no crystallization was observed after storage for 1 month at room temperature in a nitrogen atmosphere. Thus, the compound of the present invention is suitably used as a material for an organic electroluminescence device having excellent stability and heat resistance.
(Comparative Example 1)
A CBP thin film was prepared in the same manner as in Example 7. In this thin film, crystallization and cloudiness were observed in about 24 hours.

(Example 8)
An organic electroluminescent element having the structure shown in FIG. 3 was produced by the following method.
An indium tin oxide (ITO) transparent conductive film 2 deposited on a glass substrate 1 with a thickness of 150 nm (sputtered film; sheet resistance 15 Ω) is formed into a 2 mm wide stripe using normal photolithography and hydrochloric acid etching. An anode was formed by patterning. The patterned ITO substrate was cleaned in the order of ultrasonic cleaning with acetone, water with pure water, and ultrasonic cleaning with isopropyl alcohol, then dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning.
Next, an aromatic diamine-containing polyether (P-1) having the following structure as the anode buffer layer 3
(Weight average molecular weight 25,300; glass transition temperature 171 ° C.) and 10% by weight of the following compound (P-2) based on this (P-1) were spin-coated on the glass substrate under the following conditions.

Solvent Ethyl benzoate P-1 concentration 20 [mg / ml]
P-2 concentration 2 [mg / ml]
Spinner speed 1500 [rpm]
Spinner rotation time 30 [seconds]
Drying conditions 100 ° C for 1 hour

A uniform thin film having a thickness of 30 nm was formed by the above spin coating.
Next, the substrate 1 on which the anode buffer layer 3 was applied and formed was placed in a vacuum evaporation apparatus. After rough evacuation of the apparatus using an oil rotary pump, the apparatus was evacuated using a cryopump until the degree of vacuum in the apparatus was 1.0 × 10 ⁻⁴ Pa or less.
The following 4,4′-bis [N- (1-), placed in a ceramic crucible placed in the above device
Phenanthyl) -N-phenylamino] biphenyl

Vapor deposition was performed by heating with a tantalum wire heater around the crucible. At this time, the temperature of the crucible was controlled in the range of 301 to 311 ° C. A hole transport layer 4 having a thickness of 60 nm was obtained at a vacuum degree of 6.4 × 10 ⁻⁵ Pa and a deposition rate of 0.2 nm / sec.
Subsequently, as the light-emitting layer 5, the target product 1 obtained in Example 1 and the iridium complex (shown below) shown in (T-2) in the text were placed in separate ceramic crucibles, and subjected to a binary co-evaporation method. Film formation was performed.

The crucible temperature of the target product 1 is controlled to 268 ° C., the deposition rate is controlled to 0.10 nm / second, the iridium complex (T-2) is controlled to a temperature range of 267 to 268 ° C., and the iridium complex (T− The light emitting layer 5 containing 2% by weight of 2) was laminated on the hole transport layer 4. The degree of vacuum during deposition was 7.7 × 10 ⁻⁵ Pa.
Further, a compound shown as (HB-12) in the text as a hole blocking layer 6 was laminated with a crucible temperature of 181 ° C. and a film thickness of 10 nm at a deposition rate of 0.1 nm / second. Vacuum degree during deposition is 4.4 × 10 ^-5 Pa
Met.
On the hole blocking layer 6, an aluminum 8-hydroxyquinoline complex represented by the following structural formula (ET-1) as an electron transport layer 7, Al (C ₉ H ₆ NO) ₃

Was deposited. At this time, the crucible temperature of the 8-hydroxyquinoline complex of aluminum is 243 to
It was controlled in the range of 257 ° C., the degree of vacuum during deposition was 4.2 × 10 ⁻⁵ Pa, the deposition rate was 0.2 nm / second, and the film thickness was 35 nm.
The substrate temperature when vacuum-depositing the hole transport layer, the light emitting layer, the hole blocking layer, and the electron transport layer was maintained at room temperature.
Here, the element on which the electron transport layer 7 has been deposited is once taken out from the vacuum deposition apparatus into the atmosphere, and a 2 mm wide stripe-shaped shadow mask is used as a cathode deposition mask. The device was placed in close contact with each other so as to be orthogonal to each other, placed in another vacuum vapor deposition apparatus, and evacuated until the degree of vacuum in the apparatus was 5 × 10 ⁻⁴ Pa or less in the same manner as the organic layer. As the cathode 8, first, lithium fluoride (LiF) is vapor deposited at a rate of 0.01 nm / second using a molybdenum boat.
The film was formed on the electron transport layer 7 at a vacuum degree of 5 × 10 ⁻⁴ Pa and a film thickness of 0.5 nm. Next, aluminum was similarly heated by a molybdenum boat to form an aluminum layer having a thickness of 80 nm at a deposition rate of 0.5 nm / second and a degree of vacuum of 1 × 10 ⁻³ Pa, thereby completing the cathode 8. The substrate temperature at the time of vapor deposition of the above two-layer cathode 8 was kept at room temperature.

As described above, an organic electroluminescent element having a light emitting area portion having a size of 2 mm × 2 mm was obtained. The light emission characteristics of this element are shown in Table-2. In Table 2, luminous efficiency is a value at 100 cd / m ² , luminance / current is a slope of luminance-current density characteristics, and voltage is a value at 100 cd / m ² . The maximum wavelength of the emission spectrum of the device was 514 nm, which was identified as that from the iridium complex (T-2).

Example 9
A device was fabricated in the same manner as in Example 8, except that the target 1 which was the host material of the light emitting layer was replaced with the target 2 obtained in Example 2. The light emission characteristics of this element are shown in Table-1. The maximum wavelength of the emission spectrum of the device was about 514 nm, which was almost the same as in Example 8, and it was identified as that from the iridium complex (T-2).

(Comparative Example 2)
A device was fabricated in the same manner as in Example 8, except that the target 1 which was the host material of the light emitting layer was replaced with the CBP used in Comparative Example 1. The light emission characteristics of this element are shown in Table-2. The maximum wavelength of the emission spectrum of the device was 512 nm, which was almost the same as in Example 8, and was identified as that from the iridium complex (T-2). Compared with Examples 8 and 9, the luminous efficiency is low and the driving voltage is high.

(Comparative Example 3)
A device was fabricated in the same manner as in Example 8 except that the target compound 1 which is the host material of the light emitting layer was used and a similar compound of target compound 1 shown below was used. The light emission characteristics of this element are shown in Table-2. The maximum wavelength of the emission spectrum of the device was 519 nm, and the chromaticity was CIE (x, y) = (0.32, 0.61), which was identified as that from the organic iridium complex (T-2). Compared with Examples 8 and 9, the luminous efficiency is low.

(Example 10)
A device was fabricated in the same manner as in Example 8, except that the iridium complex (T-2), which is the dopant material of the light emitting layer, was replaced with the mixture containing the following blue light emitting iridium complex (X) obtained in Synthesis Example 1. did.

The light emission characteristics of this element are shown in Table-3. The maximum wavelength of the emission spectrum of the device was 486 nm, and it was identified to be from a mixture containing iridium complex (X).
(Example 11)
A device was fabricated in the same manner as in Example 10 except that the target 1 as the host material of the light emitting layer was replaced with the target 2. The light emission characteristics of this element are shown in Table-3. The maximum wavelength of the emission spectrum of the device was 484 nm, and it was identified to be from a mixture containing iridium complex (X).
(Comparative Example 4)
A device was fabricated in the same manner as in Example 10 except that the target product 1 as the host material of the light emitting layer was replaced with CBP. The light emission characteristics of this element are shown in Table-3. Compared to Examples 10 and 11, the emission spectrum is broad, the emission efficiency is low, and the drive voltage is high.

(Example 12)
As a material for the anode buffer layer 3, a material comprising a non-conjugated polymer compound (P-1) having an aromatic amino group having the structural formula shown below and an electron accepting compound (P-3) is used as a hole blocking layer. Example 8 except that the pyridine derivative (HB-21) shown below as 6 was used and the film thickness of the organic low molecular layer (layer from the hole transport layer 4 to the electron transport layer 7) was changed as described below. A device was fabricated in the same manner.
Non-conjugated polymer compound having an aromatic amino group (P-1)

Weight average molecular weight: 29400
Number average molecular weight: 12600
Electron-accepting compound (P-3): ionic compound of number A-1 described in the table in the 0059 column of Japanese Patent Application No. 2004-68958

Spin coating conditions Solvent Ethyl benzoate Coating concentration 2 [wt%]
P-1: P-3 10: 2
Spinner speed 1500 [rpm]
Spinner rotation time 30 [seconds]
Drying condition 230 ° C. 15 minutes A uniform thin film having a thickness of 30 nm was formed by the above spin coating.
Organic low molecular layer hole transport layer 4 (40 nm) 4,4′-bis [N- (1-phenanthyl) -N-phenylamino] biphenyl light emitting layer 5 (30 nm) Host material: purpose obtained in Example 1 Thing 1

  Hole blocking layer 6 (5 nm) Pyridine derivatives represented by the following structural formula (HB-21)

Electron transport layer 7 (30 nm) 8-hydroxyquinoline complex of Al (ET-1)
The light emission characteristics of this element are shown in Table-4. The maximum wavelength of the emission spectrum of the device was 515 nm, and the chromaticity was CIE (x, y) = (0.32,0.61), which was identified as that from the organic iridium complex (T-2).

(Example 13)
A device was fabricated in the same manner as in Example 12 except that the hole blocking layer 6 was not provided.
The light emission characteristics of this element are shown in Table-4. The maximum wavelength of the emission spectrum of the device was 515 nm, and the chromaticity was CIE (x, y) = (0.31,0.62), which was identified as that from the organic iridium complex (T-2). Despite the absence of the hole blocking layer, high luminous efficiency was exhibited.
(Example 14)
A device was fabricated in the same manner as in Example 12 except that the target product 6 obtained in Example 5 shown below was used instead of the target product 1 as the host material of the light emitting layer.
The light emission characteristics of this element are shown in Table-4. The maximum wavelength of the emission spectrum of the device was 515 nm, and the chromaticity was CIE (x, y) = (0.32, 0.62), which was identified as that from the organic iridium complex (T-2).

(Example 15)
A device was fabricated in the same manner as in Example 14 except that the hole blocking layer was not provided.
The light emission characteristics of this element are shown in Table-4. The maximum wavelength of the emission spectrum of the device was 515 nm, and the chromaticity was CIE (x, y) = (0.31,0.62), which was identified as that from the organic iridium complex (T-2). Despite the absence of the hole blocking layer, high luminous efficiency was exhibited.

The schematic cross section which showed an example of the organic electroluminescent element. The schematic cross section which showed another example of the organic electroluminescent element. The schematic cross section which showed another example of the organic electroluminescent element.

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 (15)

A charge transport material comprising an organic compound represented by the following general formula (I).

[ Wherein, ring A is a 5- or 6-membered monocyclic ring or an aromatic hydrocarbon ring composed of 2 to 5 condensed rings, or a 5- or 6-membered monocyclic ring or an aromatic heterocyclic ring composed of 2 to 4 condensed rings N represents an integer of 3 or more.
The ring A has a —NR ¹ R ² group at three or more adjacent substitution positions, and one or more substitution positions are unsubstituted, or a linear or branched group having 1 to 8 carbon atoms. An alkyl group having 2 to 9 carbon atoms, an alkynyl group having 2 to 9 carbon atoms, an aralkyl group having 7 to 15 carbon atoms, and an alkyl group having 1 to 8 carbon atoms which may have a substituent. An alkylamino group having one or more, an arylamino group having an optionally substituted aromatic hydrocarbon group having 6 to 12 carbon atoms, an optionally substituted 5- or 6-membered aromatic ring A heteroarylamino group having a heterocyclic group, an acylamino group having an acyl group having 2 to 10 carbon atoms which may have a substituent, an alkoxy group having 1 to 8 carbon atoms which may have a substituent, Aryloxy having an aromatic hydrocarbon group having 6 to 12 carbon atoms Heteroaryloxy group having a 5- or 6-membered aromatic ring group, an optionally substituted acyl group having 2 to 10 carbon atoms, and optionally having 2 to 10 carbon atoms Alkoxycarbonyl group, optionally substituted aryloxycarbonyl group having 7 to 13 carbon atoms, alkylcarbonyloxy group having 2 to 10 carbon atoms, carboxyl group, cyano group, hydroxyl group, mercapto group, carbon number 1 -8 alkylthio group, arylthio group having 6 to 12 carbon atoms, sulfonyl group which may have a substituent, silyl group which may have a substituent, boryl group which may have a substituent A phosphino group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and an aromatic heterocyclic group which may have a substituent (provided that the following formula R-27 the group consisting of the exception.) is It is substituted at al chosen group. Further, the n —NR ¹ R ² groups contained in one molecule may be the same or different. However, the —NR ¹ R ² group is a group represented by the following formula R-27. ]

(In the formula, L ¹ and L ² are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, an alkenyl group having 2 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. It represents a substituent selected from the group consisting of a dialkylamino group having an alkyl chain, an alkylthio group having 1 to 4 carbon atoms, and a phenyl group.) In the general formula (I), the ring A has an —NR ¹ R ² group at three or more adjacent substitution positions, and one or more substitution positions are unsubstituted. Or it is chosen from the group which consists of a C1-C8 linear or branched alkyl group, the aromatic hydrocarbon group which may have a substituent, and the aromatic heterocyclic group which may have a substituent. The charge transport material according to claim 1, wherein the charge transport material is substituted with a group having a molecular weight of 200 or less.   The charge transport according to any one of claims 1 and 2, wherein in the general formula (I), the ring A is a benzene ring or a pyridine ring, and n is 4 or 5. material. The charge transport material according to claim 1, wherein the organic compound is represented by the following general formula (II).

^(Wherein, X 1 to X ^5, the formula ^.X 1 to X ⁵ represents a group represented by R-27 are identical, respectively, may be different .A ⁰ is a hydrogen atom Or a linear or branched alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkynyl group having 2 to 9 carbon atoms, an aralkyl group having 7 to 15 carbon atoms, and a substituent. An alkylamino group having one or more alkyl groups having 1 to 8 carbon atoms, an arylamino group having an aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent, and a substituent. A heteroarylamino group having a 5- or 6-membered aromatic heterocyclic group which may have, an acylamino group having a C2-10 acyl group which may have a substituent, and a substituent. C1-C8 alkoxy group, C6-C12 aromatic An aryloxy group having a hydrocarbon group, a heteroaryloxy group having a 5- or 6-membered aromatic ring group, an optionally substituted acyl group having 2 to 10 carbon atoms, and a substituent An optionally substituted alkoxycarbonyl group having 2 to 10 carbon atoms, an optionally substituted aryloxycarbonyl group having 7 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 10 carbon atoms, a carboxyl group, a cyano group, A hydroxyl group, a mercapto group, an alkylthio group having 1 to 8 carbon atoms, an arylthio group having 6 to 12 carbon atoms, a sulfonyl group which may have a substituent, a silyl group which may have a substituent, and a substituent. Boryl group which may have, phosphino group which may have substituent, aromatic hydrocarbon group which may have substituent and aromatic heterocyclic group which may have substituent Group of It represents an al substituent selected.) In the above general formula (II), A ⁰ is a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, an aromatic hydrocarbon group or substituent which may have a substituent. The charge transport material according to claim 4, wherein the charge transport material is an aromatic heterocyclic group optionally having a molecular weight of 200 or less. In the organic compound, L ¹ and L ² in the formula R-27 are a hydrogen atom, a methyl group or a phenyl group, and A ⁰ is an aromatic heterocycle which may have a hydrogen atom, an alkyl group or a substituent. 6. The charge transport material according to claim 4, wherein the charge transport material is a group. A charge transport material comprising an organic compound represented by the following general formula (III).

^(Wherein, Y 1 to Y ⁵ are the ^.Y 1 to Y ⁵ represents a group represented by the following formula R-27, may be the same, respectively, may be different.)

(In the formula, L ¹ and L ² are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, an alkenyl group having 2 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. It represents a substituent selected from the group consisting of a dialkylamino group having an alkyl chain, an alkylthio group having 1 to 4 carbon atoms, and a phenyl group.) The charge transport material according to claim 1, wherein the organic compound has a molecular weight of 4000 or less. The organic electroluminescent element material formed by containing the organic compound in any one of Claims 1-8. The organic electroluminescent element which has a layer containing the organic compound in any one of Claims 1-8 in the organic electroluminescent element which has an anode, a cathode, and the light emitting layer provided between these both on a board | substrate. The organic electroluminescent element of Claim 10 whose layer containing the organic compound in any one of Claims 1-8 is a light emitting layer. Light-emitting layer, the organic compound according to any one of claims 1 to 8 as a host material, with respect to the host material, the organometallic complex is characterized by comprising doped, organic claim 11 Electroluminescent device. Furthermore, the organic electroluminescent element in any one of Claims 10-12 which has a hole-blocking layer which contact | connects the cathode side interface of a light emitting layer. An organic compound represented by the following general formula (III).

^(Wherein, Y 1 to Y ⁵ are the ^.Y 1 to Y ⁵ represents a group represented by the following formula R-27, may be the same, respectively, may be different.)

(In the formula, L ¹ and L ² are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, an alkenyl group having 2 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. It represents a substituent selected from the group consisting of a dialkylamino group having an alkyl chain, an alkylthio group having 1 to 4 carbon atoms, and a phenyl group.) The organic compound of Claim 14 whose molecular weight is 4000 or less.

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