JP5412809B2 - Method for producing imidazole compound - Google Patents

Description

  The present invention relates to a method for producing an imidazole compound, an organic electroluminescence element using the compound, a display device, and a lighting device.

  Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (hereinafter referred to as “ELD”). As a component of ELD, an inorganic electroluminescence element and an organic electroluminescence element (hereinafter also referred to as “organic EL element”) can be given.

  Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic EL device has a structure in which a light-emitting layer containing a light-emitting compound is sandwiched between a cathode and an anode, and excitons (excitons) are generated by injecting electrons and holes into the light-emitting layer and recombining them. The device emits light by utilizing the emission of light (fluorescence / phosphorescence) when the exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Therefore, it has a wide viewing angle, high visibility, and since it is a thin-film type completely solid element, it has attracted attention from the viewpoints of space saving and portability.

  However, in organic EL elements for practical use in the future, development of organic EL elements that emit light efficiently and with high luminance with lower power consumption is desired.

  In Japanese Patent No. 3093796, a small amount of a phosphor is doped into a stilbene derivative, a distyrylarylene derivative or a tristyrylarylene derivative to achieve an improvement in light emission luminance and a longer device lifetime.

  Moreover, the element which has an organic light emitting layer which doped 8-hydroxyquinoline aluminum complex as a host compound and a trace amount fluorescent substance to this, and the organic light emission which doped 8-quinoquinoline aluminum complex as a host compound and this to the quinacridone series pigment | dye Devices having layers are known.

  As described above, when light emission from excited singlet is used, the generation ratio of singlet excitons and triplet excitons is 1: 3, and thus the generation probability of luminescent excited species is 25%. Since the efficiency is about 20%, the limit of the external extraction quantum efficiency (η) is set to 5%.

  However, since Princeton University reported on an organic EL device using phosphorescence emission from an excited triplet (MA Baldo et al., Nature, 395, 151-154 (1998)), Research on materials that exhibit phosphorescence has become active.

  For example, M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), US Pat. No. 6,097,147, and the like.

  When the excited triplet is used, the upper limit of the internal quantum efficiency is 100%. In principle, the luminous efficiency is four times that of the excited singlet, and there is a possibility that almost the same performance as a cold cathode tube can be obtained. Therefore, it is attracting attention as a lighting application.

  For example, S.M. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), etc., many compounds are being studied for synthesis centering on heavy metal complexes such as iridium complexes.

  In addition, the aforementioned M.I. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), studies have been made using tris (2-phenylpyridine) iridium as a dopant.

In addition, M.M. E. Thompson et al. In The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) used L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac), e 0 g, Tetsuo Tsutsui, etc., again The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu), the dopant as tris (2-(p-tolyl) pyridine) iridium (Ir _{(ptpy) 3),} tris ( Studies using benzo [h] quinoline) iridium (Ir (bzq) ₃ ) and the like are being conducted (note that these metal complexes are generally called ortho-metalated iridium complexes).

  In addition, the S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001) and Japanese Patent Application Laid-Open No. 2001-247859, etc., attempts have been made to form devices using various iridium complexes.

  In order to obtain high luminous efficiency, in the 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu), Ikai et al. Uses a hole transporting compound as a host of a phosphorescent compound. In addition, M.M. E. Thompson et al. Use various electron transporting materials as a host of phosphorescent compounds, doped with a novel iridium complex.

  Orthometalated complexes in which the central metal is platinum instead of iridium are also attracting attention. With respect to this type of complex, many examples are known in which ligands are characterized.

  In either case, the light emission brightness and light emission efficiency of the light emitting device are greatly improved compared to conventional devices because the emitted light is derived from phosphorescence. There was a problem that it was lower than the conventional element.

  As described above, it is difficult for phosphorescent highly efficient light-emitting materials to shorten the light emission wavelength and improve the light emission lifetime of the device, and the performance that can withstand practical use cannot be sufficiently achieved.

  In addition, regarding wavelength shortening, introduction of an electron withdrawing group such as a fluorine atom, a trifluoromethyl group, a cyano group or the like into phenylpyridine as a substituent, and picolinic acid or a pyrazabole-based ligand as a ligand. It is known to introduce.

  However, with these ligands, the emission wavelength of the light-emitting material is shortened to achieve blue, and a high-efficiency device can be achieved. On the other hand, the light-emitting lifetime of the device is greatly deteriorated, so an improvement in the trade-off is required. It was.

  It is disclosed that a metal complex having phenylpyrazole as a ligand is a light emitting material having a short emission wavelength (see, for example, Patent Documents 1 and 2). Furthermore, a metal complex formed from a ligand having a partial structure in which a 6-membered ring is condensed to a 5-membered ring of phenylpyrazole is disclosed (for example, see Patent Documents 3 and 4). There is also a disclosure of a metal complex having a phenanthridine skeleton. (For example, refer to Patent Documents 5 and 6.)

  Among metal complexes having a phenanthridine skeleton, compounds having an imidazophenanthridine skeleton and a group of compounds similar thereto have excellent performance, but there are problems in the manufacturing process. It turns out that it is essential to solve the problem in order to further improve the performance.

  The problems of the prior art are listed below.

  Any material used for the production of a high-performance organic electroluminescent element needs to be highly pure. In order to produce a metal complex having an imidadiphenanthridine skeleton with high purity, it is necessary to produce an imidadiphenanthyridine compound as a ligand with high purity.

However, it has been found that the production methods disclosed in Patent Documents 5 and 6 that disclose metal complexes having a phenanthridine skeleton cannot obtain sufficiently high purity ligands. Furthermore, the disclosed purification method is insufficient, and further, if the purity is not improved through a more advanced purification step, the synthetic yield of the finally produced metal complex is reduced, and the produced metal complex is reduced. It has been found that there is a problem in that the purity of the resin is lowered.
International Publication No. 2004/085450 Pamphlet JP 2005-53912 A JP 2006-28101 A US Pat. No. 7,147,937 US Patent No. 20070190359 International Publication No. 2007/095118 Pamphlet

  The present invention has been made in view of the above problems and circumstances, and a solution to the problem is a high light intensity required for an organic EL element that exhibits specific short-wave light emission, exhibits high light emission efficiency, and has a long light emission lifetime. It is providing the manufacturing method of a pure imidazole compound, the imidazole compound manufactured by the manufacturing method, an organic EL element using the same, an illuminating device, and a display apparatus.

  That is, the main subject of the present invention is to provide a novel method for producing an imidazole compound, but as a basic or typical embodiment, there is a method for producing an imidazole compound represented by the following general formula (1). The present invention provides a method for producing an imidazole compound having a mode in which a compound represented by the following general formula (2) and a compound represented by the following general formula (3) are reacted in a solvent. .

[Wherein, R _{1 to} R ₉ each represents a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. X represents a halogen atom. ]
Hereinafter, in order to assist the understanding of the above-mentioned problems and the present invention, problems of the prior art and considerations thereof will be described in detail.

  First, methods for synthesizing a metal complex having an imidazophenanthridine skeleton are disclosed in Patent Documents 5 and 6 as follows. The following three examples are cited as examples.

  Cited Example 1: Example of R1 = R2 = H (From Examples 2 and 3 of Patent Document 5)

  Citation 2: Example of R1 ≠ R2 ≠ H (from Example 36 of Patent Document 5)

  Reference example 3: R1 ≠ R2 ≠ H (from Example 37 of Patent Document 5)

  That is, the reaction of a 6-aminophenanthridine derivative and α-haloaldehyde is disclosed as a method for producing imidazophenanthridine which is a ligand of a metal complex, and the reaction solvent is 2 -Propanol (Examples 2, 6, 36, etc. of Patent Document 5), NMP (N-methylpyrrolidone, Example 37 of Patent Document 5) are disclosed, and sodium carbonate is disclosed as a base. Moreover, use of silica gel column chromatography is disclosed as a purification method of the ligand.

However, in the case of R ₁ = R ₂ = H as in Citation 1 disclosed in many examples of Patent Document 5, R ₁ ≠ R ₂ as in Citation 2 and Citation 3 In some cases, it has been found that the disclosed reaction conditions and purification methods do not yield sufficiently pure ligands.

  That is, when it reacts on the reaction conditions currently disclosed by patent document 5, an unnecessary by-product other than the target ligand is produced | generated in a considerable ratio, Moreover, patent document 5 discloses. It was found that these impurities could not be completely removed by purification using silica gel column chromatography alone. Chromatography (for example, alumina etc.) using an adsorbent carrier other than silica gel was also tried, but none of them could achieve a sufficient purification effect. This is presumably because the by-product polarity is very close to the target ligand and cannot be separated by the difference in adsorptivity.

  The only purification effect was confirmed by the chromatographic purification method by GPC (gel permeation chromatography). In this method, since the separation principle is based on the difference in the bulkiness of the molecules, the purification effect can be obtained because the bulkiness of the impurities and the target molecules are somewhat different. However, this method is low in purification efficiency, and the amount of substances that can be purified in one purification operation is very low compared to silica gel chromatography and the like, and is not suitable for mass production.

  Therefore, in order to obtain a ligand having sufficient purity to produce a metal complex useful as an organic electroluminescence device material, it is necessary to develop a reaction method that suppresses the generation of impurities itself. As a purification method in this case, it is a necessary condition that a ligand with sufficient purity can be obtained only by purification by silica gel chromatography or the like having a certain degree of productivity.

  The structure of the by-product in question is not completely elucidated because not all the by-products of the same composition are produced by the individual raw materials. Can think.

  That is, two raw materials, ie, a 6-aminophenanthridine derivative and an α-haloaldehyde (or α-haloketone) are used in the ligand synthesis reaction in question here. I think that this is caused by the fact that the compound has a reaction point.

Hereinafter, a by-product isolated and confirmed in the case of R ₁ = n-Hexyl and R ₂ = H will be described as an example.

  That is, originally, 1) amino group and carbonyl group, then 2) ring nitrogen and bromine atom should react in order, but the target product should be obtained, It was found that the formation of unnecessary by-products was invited. Since the reaction between the amino group and the bromine atom is not negligible, other than this, a high molecular weight by-product such as the reaction of two or more 6-aminophenanthridine derivatives and α-haloaldehyde (or α-haloketone). It is easily speculated that the product will form. In fact, although the structure cannot be confirmed even in the purification process using GPC, the fact that many high-molecular-weight by-products are confirmed as compared with the target product is considered to support this idea.

  Therefore, in order to suppress the production of by-products, among the first two reactions that can occur from the two raw materials, the target reaction (reaction route A) is promoted, and an undesirable reaction (reaction route B) is performed. Suppressing reaction environment or target reaction has little effect, but reaction environment that suppresses undesirable reaction or target reaction is promoted but unfavorable reaction has less effect It would be good if we can give a reaction environment that doesn't exist.

<< Scope of application of the present invention >>
As a result of the study, the present inventors have studied a method for efficiently producing high-purity imidazophenanthridines, which has no problem as a ligand of a metal complex necessary for production of a high-performance organic electroluminescence device. The inventors have succeeded in finding out the present invention and have arrived at the present invention, but further examined the applicable range of the production method of the present invention.

  As a result, the raw material is not limited to the 6-aminophenanthridine derivative, but a heterocyclic amine in which two aromatic rings are condensed on the 2-aminopyridine mother nucleus and an α-haloaldehyde or α-haloketone are used as raw materials. Thus, it was confirmed that the effects of the present invention were manifested in the synthesis of imidazole derivatives, and the present invention was completed.

  That is, the production method of the imidazole compound represented by the general formula (4), (6), (8) or (10) is represented by the following general formula (5), (7), (9) or (11). And a compound represented by the above general formula (3) are reacted in a non-polar aprotic solvent to obtain a ligand of a metal complex necessary for the production of a high-performance organic electroluminescence device. The present inventors have succeeded in finding a method for efficiently producing high purity and have reached the present invention.

  Here, the raw material and the product are structurally related to each other. That is, the imidazole compound represented by the general formula (4) from the compound represented by the general formula (5), and the imidazole compound represented by the general formula (6) from the compound represented by the general formula (7). However, from the compound represented by the general formula (9), the imidazole compound represented by the general formula (8) is represented by the imidazole compound represented by the general formula (10). Indicates that each is generated.

[Wherein, E ^{1a to} E ^1k represent a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and E ^1l represents a carbon atom or a nitrogen atom. In the imidazole compound represented by the general formula (4), (6), (8) or (10), the skeleton composed of E ^{1a to} E ¹¹ and the imidazole ring has a total of 18π electrons. R ^{1b to} R ^1e and R ^{1h to} R ^1j each represent a hydrogen atom or a substituent. However, when E ^{1 *} to which R ^{1 *} is bonded is an oxygen atom or a sulfur atom, R ^{1 *} does not exist. In addition, when E1 * to which R ^{1 *} is bonded is a nitrogen atom, R ^{1 *} may not exist. Here, * represents any of the characters b, c, d, e, h, i, and j. R ₁ and R ₂ each represent a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. X represents a halogen atom. In addition, among the compounds represented by the above general formula, the raw material and the product are structurally related to each other. ]

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used the following method as a method for producing imidazophenanthridine having a substituent in at least one of 2-position and 3-position. It is possible to manufacture high-purity imidazophenanthridines, which have no problems as ligands for metal complexes necessary for the manufacture of high-performance organic electroluminescence devices, using only a purification method capable of supporting mass production. And found the present invention.

That is, the said subject which concerns on this invention is solved by the following means 1-18.
Specifically, according to the present invention, in the means 1, a nonpolar aprotic solvent having a dielectric constant of 10 or less is used as the apolar aprotic solvent , and the general formula (5), (7), (9) or (11) (and in general formula (4), (6), (8) or (10)), each of the rings formed by E ^{1a to} E ^1f and E ^{1g to} E ^1l is a 6-membered aromatic carbonization. Represents a hydrogen ring or a 5-membered or 6-membered aromatic heterocycle, the 6-membered aromatic hydrocarbon ring is a benzene ring, and the 5-membered or 6-membered aromatic heterocycle is a furan ring, a thiophene ring, or an oxazole Provided is a method for producing an imidazole compound which is a ring, an imidazole ring or a pyridine ring .

  1. A method for producing an imidazole compound represented by the following general formula (4), (6), (8) or (10), wherein the following general formula (5), (7), (9) or (11): A method for producing an imidazole compound, comprising reacting a compound represented by the following general formula (3) in a nonpolar aprotic solvent:

[Wherein, R ₁ and R ₂ each represent a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. E ^{1a to} E ^1k represent a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and E ^1l represents a carbon atom or a nitrogen atom. In the imidazole compound represented by the general formula (4), (6), (8) or (10), the skeleton composed of E ^{1a to} E ¹¹ and the imidazole ring has a total of 18π electrons. R ^{1b to} R ^1e and R ^{1h to} R ^1j each represent a hydrogen atom or a substituent. However, when E ^{1 *} to which R ^{1 *} is bonded is an oxygen atom or a sulfur atom, R ^{1 *} does not exist. In addition, when E ^{1 *} to which R ^{1 *} is bonded is a nitrogen atom, R ^{1 *} may not exist. Here, * represents any of the characters b, c, d, e, h, i, and j. In addition, among the compounds represented by the above general formula, the raw material and the product are structurally related to each other. ]
2. 2. The method for producing an imidazole compound according to 1 above, wherein the nonpolar aprotic solvent is an aromatic compound.

  3. 3. The method for producing an imidazole compound according to 1 or 2, wherein the nonpolar aprotic solvent is alkyl-substituted benzene or chloro-substituted benzene.

  4). In addition to the compound represented by the general formula (3) and the compound represented by the general formula (5), (7), (9) or (11), the reaction is performed using an organic base. The manufacturing method of the imidazole compound as described in any one of said 1 to 3.

  5. 5. The production of an imidazole compound according to 4 above, wherein 1.1 to 1.5 equivalents of the compound represented by the general formula (5), (7), (9) or (11) is used as the organic base. Method.

  6). 6. The method for producing an imidazole compound according to 4 or 5, wherein the organic base is a trialkylamine.

  7). The said reaction is performed at 50-200 degreeC, The manufacturing method of the imidazole compound as described in any one of said 1-6 characterized by the above-mentioned.

  8). The said reaction is performed at 100-150 degreeC, The manufacturing method of the imidazole compound as described in any one of said 1 to 7 characterized by the above-mentioned.

  9. Said X is bromine or chlorine, The manufacturing method of the imidazole compound as described in any one of said 1-8 characterized by the above-mentioned.

  10. A method for producing an imidazole compound represented by the following general formula (1), wherein a compound represented by the following general formula (2) and a compound represented by the following general formula (3) are nonpolar aprotic 10. The method for producing an imidazole compound according to any one of 1 to 9, wherein the reaction is performed in a solvent.

[Wherein, R _{1 to} R ₉ each represents a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. X represents a halogen atom. ]
11. An organic electroluminescence device having a light emitting layer sandwiched between an anode and a cathode, wherein the light emitting layer contains a compound containing a partial structure represented by the following general formulas (12) to (15), and The compound containing the partial structure represented by general formula (12)-(15) is manufactured using the corresponding imidazole compound manufactured with the manufacturing method as described in any one of said 1-10. An organic electroluminescence device characterized in that there is.

[Wherein, E ^{1a to} E ^1k represent a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and E ^1l represents a carbon atom or a nitrogen atom. The skeleton composed of E ^{1a to} E ¹¹ and the imidazole ring has a total of 18π electrons. R ^{1b to} R ^1e and R ^{1h to} R ^1j each represent a hydrogen atom or a substituent. However, when E ^{1 *} to which R ^{1 *} is bonded is an oxygen atom or a sulfur atom, R ^{1 *} does not exist. In addition, when E ^{1 *} to which R ^{1 *} is bonded is a nitrogen atom, R ^{1 *} may not exist. Here, * represents any of the characters b, c, d, e, h, i, and j.

R ₁ and R ₂ each represent a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. M represents a group 8-10 transition metal element in the periodic table. ]
12 12. The organic electroluminescence device as described in 11 above, wherein M is platinum or iridium.

  13. The light emitting layer contains a carbazole derivative or a derivative having a ring structure in which at least one carbon atom of a hydrocarbon ring constituting the carbazole ring of the carbazole derivative is substituted with a nitrogen atom. Or the organic electroluminescent element of 12.

  14 As a constituent layer, it has an organic layer containing at least one compound containing a partial structure represented by any one of the general formulas (12) to (15) described in 12, and the organic layer uses a wet process. 14. The organic electroluminescence device according to any one of 11 to 13, wherein the organic electroluminescence device is formed.

  15. Any one of 11 to 14 above, characterized in that it contains at least one polymer having a partial structure of a compound containing the partial structure represented by any one of the general formulas (12) to (15). The organic electroluminescent element of description.

  16. 16. The organic electroluminescence element according to any one of 11 to 15, which emits white light.

  17. A display device comprising the organic electroluminescent element according to any one of 11 to 16 above.

  18. An illumination device comprising the organic electroluminescence element according to any one of 11 to 16 above.

  By means of the present invention, a method for producing a high-purity imidazole compound necessary for an organic EL device that exhibits specific short-wave luminescence, exhibits high luminous efficiency, and has a long emission lifetime, and imidazole produced by the production method A compound, an organic EL element using the compound, a lighting device, and a display device can be provided.

  That is, by means of the present invention, it is possible to provide an organic EL element in which the initial deterioration at the start of element driving is greatly reduced, and further, the occurrence of dark spots in the light emitting element during element driving is greatly reduced. In addition, a high-performance lighting device or display device using the element can be provided.

The method for producing an imidazole compound of the present invention is a method for producing an imidazole compound having chemical structures similar to each other represented by the general formula (1), (4), (6), (8) or (10). And a compound having a chemical structure similar to each other represented by the general formula (2), (5), (7), (9) or (11), and represented by the following general formula (3): The compound is reacted with a non-polar aprotic solvent. This feature is a technical feature common (identical or corresponding) to the means 1 to 18 .

  As an embodiment of the present invention, the nonpolar aprotic solvent is preferably an aromatic compound from the viewpoint of manifesting the effects of the invention. Further, the nonpolar aprotic solvent is preferably alkyl-substituted benzene or chloro-substituted benzene.

  Moreover, in this invention, the aspect made to react using an organic base other than the compound represented by the said General formula (2), (5), (7), (9) or (11) and (3). It is preferable that In this case, it is preferable to use 1.1 to 1.5 equivalents of the compound represented by the general formula (2), (5), (7), (9) or (11). Furthermore, the organic base is preferably a trialkylamine.

  In an embodiment of the present invention, the reaction is preferably performed in a temperature range of 50 to 200 ° C, and more preferably 100 to 150 ° C.

  Moreover, it is preferable that the X in the general formula (3) is bromine or chlorine.

  The imidazole compound produced using the method for producing an imidazole compound of the present invention can be suitably used for an organic electroluminescence device. That is, the organic electroluminescence element is an organic electroluminescence element having a light emitting layer sandwiched between an anode and a cathode, and the light emitting layer has a partial structure represented by the general formulas (12) to (15). It is preferable that it is the aspect containing the compound to contain. In the general formulas (12) to (15), M (group 8 to group 10 transition metal element in the periodic table) is preferably platinum or iridium. The light-emitting layer preferably contains a carbazole derivative or a derivative having a ring structure in which at least one carbon atom of a hydrocarbon ring constituting the carbazole ring of the carbazole derivative is substituted with a nitrogen atom.

  Furthermore, the organic electroluminescence element has an organic layer containing at least one compound containing a partial structure represented by any one of the general formulas (12) to (15) as the constituent layer, It is preferable that the layer is formed using a wet process. Moreover, it is preferable to contain at least 1 type of the polymer which uses as a partial structure the compound containing the partial structure represented by either of the said General formula (12)-(15).

  The organic electroluminescence element according to the present invention can be suitably used as an element that emits white light. Therefore, the organic electroluminescence element can be suitably used for a display device and a lighting device.

  Hereinafter, the present invention, its components, and the best mode and mode for carrying out the present invention will be described in detail.

(Method for producing imidazole compound)
Among the methods for producing an imidazole compound of the present invention, the method for producing an imidazole compound represented by the following general formula (1), (4), (6), (8) or (10) is represented by the following general formula (2). , (5), (7), (9) or (11) and a compound represented by the following general formula (3) are reacted in a non-polar aprotic solvent, To do.

[Wherein, R ^{1b to} R ^1j each represents a hydrogen atom or a substituent. R ₁ and R ₂ each represent a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. X represents a halogen atom. The compounds represented by the general formulas (1) to (3) are the same as the compounds represented by the general formulas (1) to (3) described in the means 10 , respectively. ]

[Wherein, E ^{1a to} E ^1k represent a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and E ^1l represents a carbon atom or a nitrogen atom. In the imidazole compound represented by the general formula (4), (6), (8) or (10), the skeleton composed of E ^{1a to} E ¹¹ and the imidazole ring has a total of 18π electrons. R ^{1b to} R ^1e and R ^{1h to} R ^1j each represent a hydrogen atom or a substituent. However, when E ^{1 *} to which R ^{1 *} is bonded is an oxygen atom or a sulfur atom, R ^{1 *} does not exist. In addition, when E1 * to which R ^{1 *} is bonded is a nitrogen atom, R ^{1 *} may not exist. Here, * represents any of the characters b, c, d, e, h, i, and j. R ₁ and R ₂ each represent a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. In addition, among the compounds represented by the above general formula, the raw material and the product are structurally related to each other. ]
The present invention provides a compound represented by the general formula (2), (5), (7), (9) or (11) and a compound represented by the general formula (3) in a nonpolar aprotic solvent. In the method for producing an imidazole compound represented by the general formula (1), the solvent used for the reaction can be freely selected as long as it is nonpolar aprotic.

  The “aprotic solvent” is a solvent having no proton donating property, and the “nonpolar solvent” is a solvent having a dielectric constant of 10 or less.

  Examples of nonpolar aprotic solvents include hydrocarbon compounds (eg, hexane, heptane, octane, dodecane, etc.), aromatic hydrocarbon compounds (eg, toluene, xylene, mesitylene, tetramethylbenzene, etc.), halogens Aromatic hydrocarbon compounds (chlorobenzene, dichlorobenzene, trichlorobenzene, etc.), ether compounds (dibutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dioxane, etc.), ester compounds (ethyl acetate, butyl acetate, ethyl butyrate, Etc.).

  Preferred is a solvent selected from aromatic hydrocarbon compounds and halogenated aromatic hydrocarbon compounds, and more preferred is a solvent selected from alkyl-substituted benzenes and halogen-substituted benzenes.

  These have an appropriate boiling point (100 ° C. to 200 ° C.) and well dissolve phenanthridines as raw materials, phenanthridines, α-haloaldehydes, α-haloketones as reaction raw materials, etc. It is selected from the fact that it is an inert solvent that does not react with, and that it is industrially available at a relatively low cost.

  In the present invention, the reaction proceeds without adding a base during the reaction. When no base is added, half of the raw material phenanthridine acts as a base and combines with the hydrogen halide produced during the reaction to form a salt. Therefore, the reaction yield based on aminophenanthridine is 50. % Cannot be exceeded. Therefore, in order to use aminophenanthyridines efficiently, it is preferable to add a base during the reaction.

  The base added during the reaction is preferably an organic base because it is required to have good compatibility with the solvent. Examples of the organic base include alkylamines (triethylamine, diisopropylethylamine, tripropylamine, tributylamine, etc.) and pyridines (pyridine, α-picoline, β-picoline, γ-picoline, 4-aminopyridine, etc.). It is done.

  With regard to the type of base, if the basicity is weak, an equilibrium occurs with respect to the capture of hydrogen halide with the raw material phenanthridine, which may reduce the utilization rate of phenanthridine. It is preferable to use a base that is so basic that such equilibrium can be ignored. Specifically, it is preferable to use alkylamines among the organic bases mentioned above. Furthermore, a trialkylamine is preferable from the viewpoint of solubility, boiling point and the like.

  The amount of base used is to capture the hydrogen halide generated during the reaction without leaking, so it is preferable to use more than the generated hydrogen halide. However, if the amount used is too large, the amount of the solvent including the base Since the reaction is adversely affected by increasing the polarity or lowering the boiling point of the solvent, it is not preferable to use it excessively. Preferably, it can be made to function as necessary and sufficiently by using 1.1 to 1.5 equivalents with respect to the raw material phenanthridine.

  Regarding the reaction temperature, if the solubility of the raw material phenanthridine is sufficient, the reaction proceeds at a reaction temperature of 50 ° C. or higher. If the boiling point of the solvent is sufficiently high, the reaction can be completed in a short time by reacting at a temperature of about 200 ° C.

  In order not to unnecessarily increase the reaction time, the reaction temperature is preferably 100 ° C. or higher. Although it is influenced by the reactivity of each raw material, if it reacts at this temperature, reaction will be completed in several hours-several dozen hours. Further, if the reaction temperature is raised too much, the organic base is vaporized to reduce the action as a base, or low-boiling α-haloaldehyde, α-haloketone, etc. may be vaporized to reduce the reactivity. It is preferable to keep the temperature to about ℃.

  The α-haloaldehyde or α-haloketone as the raw material may be bromine or chlorine as the halogen from the viewpoint of the availability of the raw material, the ease of synthesis of the raw material, and the reactivity of the raw material compound itself. preferable.

《Metal complex》
The metal complex (also referred to as “metal complex compound”) manufactured using the ligand manufactured by the manufacturing method of the present invention will be described.

  The present inventors paid attention to the organic EL element material used for the light emitting layer of the organic EL element, and examined various metal complex compounds used as a light emitting dopant.

  The present inventors have introduced a substituent into the basic skeleton of a metal complex, and thus it is not a conventionally known approach to control the wavelength or improve the lifetime, but to expand the π-conjugated surface of the condensed ring. Various complexes were studied under the focus of increasing stability.

  As a result, the improvement tendency of lifetime was found in several condensed ring structures. However, when a fused ring as known so far is introduced, the red shift of the emission wavelength is remarkable, resulting in green and red emission.

  The present inventors have further studied, and compounds (metal complexes, metals) in which a condensed ring as shown in the partial structure represented by any one of the general formulas (12) to (15) according to the present invention is introduced. In the case where a complex compound) is applied to a light emitting material, the present inventors have succeeded in developing a light emitting dopant having a small emission wavelength shift and a long lifetime at a desired emission wavelength.

  Further examination of this new basic skeleton has the disadvantage that the π-conjugate plane becomes larger, and the planarity becomes higher, so that the association between metal complexes becomes a problem, and the lifetime of the device is remarkably reduced. I understood.

  As for the waveform, sub-luminescence is seen on the long wave side, and a decrease in color purity has become a problem. As a result of various studies, by introducing at least one substituent into the imidazole part of the ligand, association between molecules can be prevented, side-light emission on the long wave side can be suppressed, and metal complexes (metal complex compounds) It was found that stability was also improved.

  The transition metal complex compound including the partial structure represented by any one of the general formulas (12) to (15) according to the present invention includes a plurality of ligands depending on the valence of the transition metal element represented by M. The ligands may all be the same, or may have ligands each having a different structure.

  Here, the ligand is a portion obtained by removing the transition metal element M from the partial structure represented by any one of the general formulas (12) to (15).

(Conventionally known ligand)
Moreover, as what is called a ligand, the said trader can use together a well-known ligand (it is also called a coordination compound) as a ligand as needed.

  From the viewpoint of preferably obtaining the effects described in the present invention, the type of ligand in the complex is preferably composed of 1 to 2 types, and more preferably 1 type.

  There are various known ligands used in conventionally known metal complexes. For example, “Photochemistry and Photophysics of Coordination Compounds” Springer-Verlag H. Published by Yersin in 1987, “Organometallic Chemistry-Fundamentals and Applications-” Liu Huabo Company, Akio Yamamoto, published in 1982, etc. (for example, halogen ligands (preferably chlorine ligands), Nitrogen heterocyclic ligands (for example, bipyridyl, phenanthroline, etc.) and diketone ligands).

(Transition metal element of group 8-10 of the periodic table)
As a metal used for forming a compound (also referred to as a transition metal complex, a metal complex, or a metal complex compound) containing a partial structure represented by any one of the general formulas (12) to (15) according to the present invention, A transition metal element belonging to Group 8 to 10 of the periodic table (also referred to simply as a transition metal) is used, among which iridium and platinum are preferable transition metal elements.

(Contained layer of transition metal complex according to the present invention)
The transition metal complex compound-containing layer including the partial structure represented by any one of the general formulas (12) to (15) according to the present invention is not particularly limited as long as it is a layer that transports charges (charge transport layer). However, a hole transport layer or a light emitting layer, a light emitting layer or an electron blocking layer is preferable, a light emitting layer or an electron blocking layer is more preferable, and a light emitting layer is particularly preferable.

  Moreover, when it contains in a light emitting layer, by using as a light emission dopant in a light emitting layer, the efficiency improvement (high brightness) of the external extraction quantum efficiency of the organic EL element of this invention and the lifetime improvement of a light emission lifetime are achieved. be able to. The constituent layers of the organic EL element of the present invention will be described in detail later.

  Next, the partial structure represented by any of the general formulas (12) to (15) according to the present invention will be described.

<< Partial structure represented by any one of general formulas (12) to (15) >>
The partial structure represented by any one of the general formulas (12) to (15) according to the present invention will be described.

In the partial structure represented by any one of the general formulas (12) to (15), the ring formed by E ^{1a to} E ^1f is a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocycle. Represents a ring.

Examples of the 6-membered aromatic hydrocarbon ring formed by E ^{1a to} E ^1f include a benzene ring. Furthermore, you may have the substituent mentioned later.

Examples of the 5-membered or 6-membered aromatic heterocycle formed by E ^{1a to} E ^1f include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. Etc.

  Each of these rings may further have a substituent described later.

In the partial structure represented by any one of the general formulas (12) to (15), the ring formed by E ^{1g to} E ¹¹ is a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocycle. These rings represent the same meaning as the 6-membered aromatic hydrocarbon ring or 5-membered or 6-membered aromatic heterocycle formed by E ^{1a to} E ^1f , respectively.

In the partial structure represented by any one of the general formulas (12) to (15), each of the substituents represented by R ^{1b to} R ^1j includes an alkyl group (for example, a methyl group, an ethyl group, a propyl group, and an isopropyl group). Group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (for example, vinyl) Group, allyl group, etc.), alkynyl group (for example, ethynyl group, propargyl group, etc.), aryl group (for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group) , Acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, Phenylyl group, heteroaryl group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazole-1-) Yl, 1,2,3-triazol-1-yl, etc.), oxazolyl, benzoxazolyl, thiazolyl, isoxazolyl, isothiazolyl, furazanyl, thienyl, quinolyl, benzofuryl, dibenzofuryl Group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the previous carbolinyl group is replaced by a nitrogen atom), Quinoxalinyl group, pyridazinyl group, tria Nyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, Hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, Methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (for example, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (for example, phenylthio group, Naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, Naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group) , Phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl) Group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group) , Ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonyl) Amino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecyl Carbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, Octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc., ureido group (for example, methylureido group, ethylureido group, pentylureido) Group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.) Sulfinyl group (eg, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl Group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group) 2-pyridylsulfonyl group), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentyla) Group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon group (eg. , Fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group) Group, phenyldiethylsilyl group, etc.), phosphono group and the like. These substituents may be further substituted with the above substituents.

  A plurality of these substituents may be bonded to each other to form a ring, and when a plurality of substituents are present, each substituent may be the same or different, and linked to each other to form a ring. May be formed.

<< Polymerizable substituent >>
In the partial structure represented by any one of the general formulas (12) to (15), the substituents represented by R ^{1b to} R ^1j are styryl group, epoxy group, oxetanyl group, You may have polymeric groups, such as an acryl group and a methacryl group.

  Furthermore, the compound represented by the partial structure represented by any one of the general formulas (1) to (4) can react with the polymerizable groups or with other polymerizable monomers to form a polymer. .

  When a plurality of partial structures are present in the polymer, the partial structures represented by any one of the general formulas (1) to (4) may be the same or different.

<Method of polymerizing a partial structure represented by any one of the general formulas (12) to (15)>
The polymer (polymer) of the partial structure represented by any one of the general formulas (12) to (15) is “Revised Polymer Synthesis Chemistry” Chemistry “Polymer Synthesis Experimental Method” Chemistry Dojin “4th Edition Experiment It can be synthesized using the method described in Chemistry Course 28 “Polymer Synthesis” Maruzen et al.

  Preferable polymerization methods include 1) polycondensation, 2) radical polymerization, 3) ionic polymerization, 4) polyaddition, addition condensation, and the like, which can be used depending on the type of polymerizable group.

  The polymer having a partial structure represented by any one of the general formulas (12) to (15) can be made into a homopolymer using the above method, or can be made into a copolymer combined with a plurality of monomers. is there.

  Specific examples of the compound (also referred to as a metal complex or a metal complex compound) containing a partial structure represented by any one of the general formulas (12) to (15) according to the present invention are shown below. It is not limited.

The substituents J1 to J15 and the secondary ligand (X ₁ -L ₁ -X ₂ ) used in the table are shown below.

  Substituent: * indicates a bond at a binding site with another part of the molecule.

Subsidiary ligand: was shown in the form that is bound to M _1.

  These metal complexes are described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), Organic Letter, vol. 3, pages 415 to 418 (2006), and further by applying methods such as references described in these documents.

  Although the synthesis example of the metal complex based on this invention is shown below, this invention is not limited to these.

  << Synthesis Example: Synthesis of Exemplary Compound A-1 >>

Step 1: Synthesis of Complex A A 100 ml four-necked flask was charged with 1.5 g of 2-methylimidazo [1,2-f] phenanthridine, 13 ml of 2-ethoxyethanol, and 3 ml of water, a nitrogen blowing tube, a thermometer, a condenser And set on an oil bath stirrer.

To this, 0.55 g of IrCl ₃ .3H ₂ O and 0.16 g (0.001560 mol) of triethylamine were added, and the reaction was completed by boiling and refluxing at an internal temperature of about 100 ° C. for 6 hours under a nitrogen stream. .

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added, and the precipitated solid was collected by filtration. The obtained solid was thoroughly washed with methanol and dried to obtain 1.37 g (77.0%) of complex A.

Step 2: Synthesis of complex B In a 50 ml four-necked flask, 1.0 g (0.0007244 mol) of complex A, 0.29 g of acetylacetone, 1.0 g of sodium carbonate, and 24 ml of 2-ethoxyethanol were introduced, and nitrogen was blown into the flask. A tube, a thermometer and a condenser were attached and set on an oil bath stirrer.

  Under nitrogen flow, the mixture was heated and stirred at an internal temperature of about 80 ° C. for 1.5 hours.

  After completion of the reaction, the reaction solution was cooled to room temperature, methanol was added to the reaction solution, and the precipitated crystals were filtered. The crystals were washed with 30 ml of water and 10 ml of MeOH and dried to obtain 0.42 g of complex D (38.5%).

Step 3: Synthesis of Exemplary Compound A-1 In a 50 ml four-necked flask, 0.386 g (0.0005120 mol) of complex B, 0.357 g of 2-methylimidazo [1,2-f] phenanthridine, glycerin 20 ml was added, and a nitrogen blowing tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. The reaction was completed by heating and stirring for 4.5 hours at an internal temperature of 150 ° C. under nitrogen flow.

  After completion of the reaction, the mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.38 g of crude crystals.

  The crystals are purified by column chromatography (developing solvent: toluene / ethyl acetate), and the obtained crystals are heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, filtered, and 0.3 g (66. 6%).

  The structure of the obtained exemplary compound A-1 was confirmed using 1H-NMR (nuclear magnetic resonance spectrum). Measurement conditions, chemical shift of each peak of the obtained spectrum, proton number, etc. are shown below.

¹ H-NMR (400 MHz, tetrahydrofuran-d8)
Measuring apparatus: JEOL JNM-AL400 (400 MHz): manufactured by JEOL Ltd. Spectrum attribution (chemical shift δ, proton number, peak shape)
8.48 (3H, d), 7.93 (3H, d), 7.75 (3H, s), 7.64 (3H, d), 7.54 (3H, t), 7.46 (3H) , T), 6.95 (3H, t), 6.83 (3H, d), 1.85 (9H, s) The emission maximum wavelength at 77 K in 2-methyltetrahydrofuran solution of Exemplified Compound A-1 is It was 455 nm.

  << Synthesis Example: Synthesis of Exemplary Compound A-65 >>

Step 1: Synthesis of Complex C A 100 ml four-necked flask was charged with 2.3 g of 3-mesityl-6-methylimidazo [1,2-f] phenanthridine, 13 ml of 2-ethoxyethanol, 3 ml of water, a nitrogen blowing tube, A thermometer and a condenser were attached and set on an oil bath stirrer.

To this, 0.55 g of IrCl ₃ .3H ₂ O and 0.16 g (0.001560 mol) of triethylamine were added, and the reaction was completed by bubbling and refluxing at an internal temperature of about 100 ° C. for 6 hours under nitrogen flow. .

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added, and the precipitated solid was collected by filtration. The obtained solid was thoroughly washed with methanol and dried to obtain 2.08 g (72.0%) of Complex C.

Step 2: Synthesis of Complex D In a 50 ml four-necked flask, 1.0 g (0.000540 mol) of Complex C, 0.25 g of acetylacetone, 1.0 g of sodium carbonate, and 24 ml of 2-ethoxyethanol were introduced, and nitrogen was blown into the flask. A tube, a thermometer and a condenser were attached and set on an oil bath stirrer.

  The mixture was heated and stirred for 1.5 hours at about 80 ° C. under nitrogen flow.

  After completion of the reaction, the reaction solution was cooled to room temperature, methanol was added to the reaction solution, and the precipitated crystals were filtered. The crystals were washed with 30 ml of water and 10 ml of MeOH and dried to obtain 0.37 g of Complex D (35%).

Step 3: Synthesis of Exemplified Compound A-65 In a 50 ml four-necked flask, 0.370 g (0.0003740 mol) of Complex D, 0.540 g of 3-mesityl-6-methylimidazo [1,2-f] fe Nanthridine and 20 ml of glycerin were added, and a nitrogen blowing tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. The reaction was completed by heating and stirring for 4.5 hours at an internal temperature of 150 ° C. under nitrogen flow.

  After completion of the reaction, the mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.37 g of crude crystals.

  The crystals are purified by column chromatography (developing solvent: toluene / ethyl acetate), and the obtained crystals are heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, followed by filtration, and 0.3 g (64.64) of Exemplified Compound A-65. 7%).

  The structure of the obtained exemplary compound A-65 was confirmed using 1H-NMR (nuclear magnetic resonance spectrum). Measurement conditions, chemical shift of each peak of the obtained spectrum, proton number, etc. are shown below.

¹ H-NMR (400 MHz, dichloromethane-d2)
Measuring apparatus: JEOL JNM-AL400 (400 MHz): manufactured by JEOL Ltd. Spectrum attribution (chemical shift δ, proton number, peak shape)
8.32 (3H, d), 7.64 (3H, d), 7.22 (3H, d), 7.13 (3H, t), 7.05 (3H, d), 7.01 (3H) , S), 6.98 (3H, s), 6.91 (3H, s), 6.85 (3H, s), 2.36 (3H, s), 2.13 (3H, s), 2 .00 (3H, s), 1.86 (3H, s)
The emission maximum wavelength at 77 K in the 2-methyltetrahydrofuran solution of Exemplified Compound A-97 was 456 nm.

  In the present invention, the emission wavelength of the exemplified compound was measured as follows. First, an absorption spectrum of the exemplary compound is measured, and an absorption maximum wavelength in the range of 300 to 350 nm is set as excitation light.

  Using the set excitation light, the emission wavelength is measured with a fluorometer F-4500 (manufactured by Hitachi, Ltd.) while performing nitrogen bubbling.

  In addition, although there is no restriction | limiting in the solvent which can be used, 2-methyltetrahydrofuran, a dichloromethane, etc. are used preferably from a soluble viewpoint of a compound.

The concentration at the time of measurement is preferably sufficiently diluted, and specifically, it is preferably measured in the range of 10 ⁻⁶ to 10 ⁻⁴ mol / l.

  Moreover, there is no restriction | limiting in particular as temperature at the time of measurement, However, Generally, it is preferable that temperature setting of the range of room temperature-77K is performed.

(Organic electroluminescence device)
The imidazole compound produced by using the method for producing an imidazole compound of the present invention can be suitably used for an organic electroluminescence device (hereinafter also referred to as “organic EL device”). That is, the organic electroluminescence element is an organic electroluminescence element having a light emitting layer sandwiched between an anode and a cathode, and the light emitting layer has a partial structure represented by the general formulas (12) to (15). It is preferable that it is the aspect containing the compound to contain. In the general formulas (12) to (15), M (group 8 to group 10 transition metal element in the periodic table) is preferably platinum or iridium. The light-emitting layer preferably contains a carbazole derivative or a derivative having a ring structure in which at least one carbon atom of a hydrocarbon ring constituting the carbazole ring of the carbazole derivative is substituted with a nitrogen atom.

  Furthermore, the organic electroluminescence element has an organic layer containing at least one compound containing a partial structure represented by any one of the general formulas (12) to (15) as the constituent layer, It is preferable that the layer is formed using a wet process. Moreover, it is preferable to contain at least 1 type of the polymer which uses as a partial structure the compound containing the partial structure represented by either of the said General formula (12)-(15).

  The organic electroluminescence element according to the present invention can be suitably used as an element that emits white light. Therefore, the organic electroluminescence element can be suitably used for a display device and a lighting device.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element of the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode In the organic EL device of the present invention, the blue light emitting layer preferably has a light emission maximum wavelength of 430 to 480 nm, and the green light emitting layer has a light emission maximum wavelength of 510 to 550 nm, The red light emitting layer is preferably a monochromatic light emitting layer having a light emission maximum wavelength in the range of 600 to 640 nm, and is preferably a display device using these. Alternatively, a white light emitting layer may be formed by laminating at least three light emitting layers. Further, a non-light emitting intermediate layer may be provided between the light emitting layers. The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  Each layer which comprises the organic EL element of this invention is demonstrated.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 to 200 nm, and particularly preferably in the range of 10 to 20 nm.

  For the production of the light-emitting layer, a light-emitting dopant or a host compound, which will be described later, is formed by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink-jet method. it can.

  The light emitting layer of the organic EL device of the present invention preferably contains a light emitting host compound and at least one kind of light emitting dopant (such as a phosphorescent dopant (also referred to as a phosphorescent dopant) or a fluorescent dopant).

(Host compound)
A host compound (also referred to as a light-emitting host or the like) used in the present invention will be described.

  Here, the host compound in the present invention is a phosphorescent quantum yield of phosphorescence emission at a room temperature (25 ° C.) having a mass ratio of 20% or more in the compound contained in the light emitting layer. Is defined as a compound of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

  As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the efficiency of the organic EL element can be further increased. Moreover, it becomes possible to mix different light emission by using multiple types of light emission dopants mentioned later, and, thereby, arbitrary luminescent colors can be obtained.

  The light emitting host used in the present invention may be a low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). Alternatively, one or a plurality of such compounds may be used.

  Although the specific example of the host compound preferably used for this invention below is shown, this invention is not limited to these.

  As a known host compound that may be used in combination, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

  Specific examples of known host compounds include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

(Luminescent dopant)
The light emitting dopant according to the present invention will be described.

  As the light-emitting dopant according to the present invention, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) can be used. From the viewpoint of obtaining an organic EL device with high luminous efficiency, the light emitting dopant used in the light emitting layer or the light emitting unit of the organic EL device of the present invention (sometimes simply referred to as a light emitting material) contains the above host compound. At the same time, it is preferable to contain a phosphorescent dopant.

(Phosphorescent dopant)
The phosphorescent dopant according to the present invention will be described.

  The phosphorescent dopant according to the present invention is a compound in which light emission from an excited triplet is observed. Specifically, the phosphorescent dopant is a compound that emits phosphorescence at room temperature (25 ° C.) and has a phosphorescence quantum yield of 25. Although it is defined as a compound of 0.01 or more at ° C., a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

  There are two types of light emission of phosphorescent dopants in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. The energy transfer type that obtains light emission from the phosphorescent dopant, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. Although it is a trap type, in any case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

  The phosphorescent dopant can be appropriately selected from known materials used for the light emitting layer of the organic EL device.

  The phosphorescent dopant according to the present invention is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound), Rare earth complexes, most preferably iridium compounds.

  The compound used as the phosphorescent dopant according to the present invention is preferably a transition metal complex compound including a partial structure represented by any one of the general formulas (1) to (4) according to the present invention.

  Moreover, you may use together a conventionally well-known light emission dopant as shown below.

(Fluorescent dopant)
Fluorescent dopants (also referred to as fluorescent compounds) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes. Perylene dyes, stilbene dyes, polythiophene dyes, rare earth complex phosphors, and the like.

  Next, an injection layer, a blocking layer, an electron transport layer, and the like used as a constituent layer of the organic EL element of the present invention will be described.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking.

  Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

  The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  The hole blocking layer contains the carbazole derivative, carboline derivative, or diazacarbazole derivative (shown in which any one of the carbon atoms constituting the carboline ring of the carboline derivative is replaced by a nitrogen atom). It is preferable to contain.

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

  The ionization potential is defined by the energy required to emit an electron at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained by the following method, for example.

  (1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  (2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved.

  Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thicknesses of the hole blocking layer and the electron transport layer according to the present invention are preferably 3 nm to 100 nm, and more preferably 5 to 30 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, these materials are preferably used because a light-emitting element with higher efficiency can be obtained.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like.

  Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Also, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg, Cu , Ca, Sn, Ga, or Pb can also be used as an electron transport material.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and hole transport layer Can also be used as an electron transporting material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method. A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
As a support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic, etc., and it is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. A high barrier film having a permeability of 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, and ceramic substrates.

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more.

  Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited.

  Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

  In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned.

Furthermore, the polymer film has an oxygen permeability of 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less measured by a method according to JIS K 7126-1987, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive.

  Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435), A method of improving efficiency by providing a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951) Gazette).

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.

  In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating in any layer or medium (in a transparent substrate or transparent electrode), and the light is removed. I want to take it out.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much.

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.

  At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.

  The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL device of the present invention is processed on the light extraction side of the substrate so as to provide, for example, a microlens array structure, or combined with a so-called condensing sheet, for example, with respect to a specific direction, for example, the device light emitting surface. By condensing in the front direction, the luminance in a specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode will be described.

  First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm, thereby producing an anode.

  Next, organic compound thin films such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer, which are organic EL element materials, are formed thereon.

  As a method for forming each of these layers, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, printing method) and the like as described above, but it is easy to obtain a homogeneous film and it is difficult to generate pinholes. In view of the above, film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is preferable in the present invention.

  Examples of the liquid medium for dissolving or dispersing the organic EL material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used. Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

  After these layers are formed, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm. By providing, a desired organic EL element can be obtained.

  Further, it is also possible to reverse the production order and produce the cathode, the electron transport layer, the hole blocking layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.

  In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE1931 color system at 1000 cd / m ² is X when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

  First, the effects of the present invention will be described with reference to the synthesis of an imidazole compound that becomes a ligand of a metal complex and the synthesis of metal complexes A to F using the ligand.

Synthesis Example 1: Synthesis of Metal Complex A-1
Step 1: Synthesis of ligand (method of the present invention)

  A 100 ml three-headed flask was charged with a solution of 3.88 g (20 mmol) of phenanthridine-6-amine in 50 ml of toluene and 4.71 g (30 mmol) of 2-chloroacetaldehyde (50% aqueous solution) while heating in a 140 ° C. oil bath. The reaction was carried out for 2 hours under reflux. Next, 3.04 g (30 mmol) of triethylamine was added, and the reaction was further performed under reflux for 2 hours. The reaction was completed after confirming the disappearance of the raw materials by thin layer chromatography.

  The reaction solution was filtered to remove insolubles, and then concentrated under reduced pressure until the volume was reduced to about half. The solution was purified by silica gel column chromatography (hexane-tetrahydrofuran = 10: 1 to 2: 1) to obtain 3.75 g (yield 86%) of imidazo [1,2, f] phenanthridine.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.0%.

  Step 2: Synthesis of metal complex A

  In a 50 ml four-necked flask, put 1.22 g (2.5 mmol) of trisacetylacetonatoiridium complex, 2.73 g of imidazo [1,2-f] phenanthridine, 10 drops of tridecane, a nitrogen blowing tube, temperature The total was set on an oil bath stirrer with an air-cooled tube attached. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 1.03 g of crude crystals.

  The crystal was purified by column chromatography (developing solvent: toluene / ethyl acetate), and the obtained crystal was heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, followed by filtration to obtain 0.83 g (39.3%) of metal complex A. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.3%.

Synthesis Comparative Example 1: Synthesis of Metal Complex A-2
Step 1: Synthesis of ligand (method described in US Pat. No. 2,070,190,359)

  In a 100 ml three-headed flask, 3.88 g (20 mmol) of phenanthridine-6-amine in 100 ml of 2-propanol, 4.71 g (30 mmol) of 2-chloroacetaldehyde (50% aqueous solution), and 4.77 g (45 mmol) of sodium carbonate were added. The mixture was reacted for 2 hours under reflux at an internal temperature of 80 ° C. The reaction was completed after confirming the disappearance of the raw materials by thin layer chromatography.

  The reaction solution was concentrated under reduced pressure to completely remove the solvent, and then purified by sika gel column chromatography (hexane-tetrahydrofuran = 10: 1 to 2: 1) to obtain 3.67 g of imidazo [1,2, f] phenanthridine. (Yield 84%) was obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 97.0%.

  Step 2: Synthesis of metal complex A

  In a 50 ml four-necked flask, put 1.22 g (2.5 mmol) of trisacetylacetonatoiridium complex, 2.73 g of imidazo [1,2-f] phenanthridine, 10 drops of tridecane, a nitrogen blowing tube, temperature The total was set on an oil bath stirrer with an air-cooled tube attached. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.97 g of crude crystals.

  After purifying the crystals by column chromatography (developing solvent toluene / ethyl acetate), the obtained crystals were heated with a mixed solvent of tetrahydrofuran and ethyl acetate, filtered, and 0.79 g (37.4%) of metal complex A was filtered. Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 98.4%.

  From the comparison between Synthesis Example 1 and Synthesis Comparative Example 1, in the synthesis of imidazo [1,2-f] phenanthridine having no substituent at the 2,3-position, the method of the present invention is not between It can be seen that there is not much difference in yield and purity.

Synthesis Example 2: Synthesis of metal complex B-1
Step 1: Synthesis of ligand (method of the present invention)

  A solution of 3.88 g (20 mmol) of phenanthridine-6-amine in 50 ml of toluene, 2.78 g (30 mmol) of chloroacetone, and 3.04 g (30 mmol) of triethylamine are placed in a 100 ml three-head flask and heated in an oil bath at 140 ° C. The reaction was carried out for 3 hours under reflux. The reaction was completed after confirming the disappearance of the raw materials by thin layer chromatography.

  The reaction solution was filtered to remove insolubles, and then concentrated under reduced pressure until the volume was reduced to about half. The solution was purified by column gel chromatography (hexane-tetrahydrofuran = 10: 1 to 2: 1) to obtain 4.09 g of 2-methylimidazo [1,2, f] phenanthridine (yield 88%). .

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.0%.

  Step 2: Synthesis of metal complex B

  Into a 50 ml four-necked flask, put 1.22 g (2.5 mmol) of trisacetylacetonatoiridium complex, 2.90 g of 2-methylimidazo [1,2-f] phenanthridine, 10 drops of tridecane, and blow nitrogen. A tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 1.23 g of crude crystals.

  The crystal was purified by column chromatography (developing solvent: toluene / ethyl acetate), and the obtained crystal was heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, and then filtered to obtain 1.07 g (48.0%) of metal complex B. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.4%.

Synthesis Comparative Example 2: Synthesis of metal complex B-2
Step 1: Synthesis of ligand (method described in US Pat. No. 2,070,190,359)

  A 100 ml three-headed flask was charged with 7.76 g (40 mmol) of phenanthridine-6-amine in 200 ml of 2-propanol, 5.56 g (60 mmol) of chloroacetone, and 9.54 g (90 mmol) of sodium carbonate. The reaction was carried out for 24 hours under reflux. The reaction was completed after confirming the disappearance of the raw materials by thin layer chromatography.

  The reaction solution was concentrated under reduced pressure to completely remove the solvent, and then purified by silica gel column chromatography (hexane-tetrahydrofuran = 10: 1 to 2: 1) to obtain 2-methylimidazo [1,2, f] phenanthridine. 4.36 g (yield 47%) was obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 82.0%.

  Since the purity was low, chromatographic purification by a recycle GPC method using tetrahydrofuran as an eluent was performed. The product was split in half and half was purified.

  Since high molecular weight components that were difficult to confirm by thin layer chromatography were included, recycle purification was performed several times to remove high molecular weight components.

  The recovered target product was 1.73 g (yield 37.2% [converted]).

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) improved to 98.3%.

  Step 2: Synthesis of metal complex B

2-1: Synthesis Using Low-Purity Ligands A metal complex was synthesized using a ligand (HPLC purity: 82.0%) that had only been purified by Sicagel column chromatography.

  Into a 50 ml four-necked flask, put 0.73 g (1.5 mmol) of trisacetylacetonatoiridium complex, 1.74 g of 2-methylimidazo [1,2-f] phenanthridine, 10 drops of tridecane, and blow nitrogen. A tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.55 g of crude crystals.

  The crystal was purified by column chromatography (developing solvent: toluene / ethyl acetate), and the obtained crystal was heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, and then filtered to obtain 0.48 g (36.1%) of metal complex B. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 98.3%.

2-2: Synthesis using a high-purity ligand In addition to purification by Sicagel column chromatography, a metal complex was prepared using a ligand (HPLC purity: 98.3%) that was chromatographically purified by the GPC method. Synthesized.

  Into a 50 ml four-necked flask, put 0.73 g (1.5 mmol) of trisacetylacetonatoiridium complex, 1.73 g of 2-methylimidazo [1,2-f] phenanthridine, 10 drops of tridecane, and blow nitrogen. A tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.70 g of crude crystals.

  The crystal was purified by column chromatography (developing solvent: toluene / ethyl acetate), and the obtained crystal was heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, and then filtered to obtain 0.61 g (45.9%) of metal complex B. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.0%.

  From the comparison between Synthesis Example 2 and Synthesis Comparative Example 2, in the synthesis of imidazo [1,2-f] phenanthridine having a substituent at the 2-position, the method of the present invention produces a high-purity product in high yield. On the other hand, in the known method, the yield is lowered and the purity of the product obtained by silica gel column chromatographic purification is also low. The purity can be increased by chromatographic purification by the GPC method, but the final yield is further reduced.

  From the comparison between Synthesis Example 2 and Synthesis Comparative Example 2, synthesis of a metal complex having imidazo [1,2-f] phenanthridine having a substituent at the 2-position as a ligand is also synthesized by the method of the present invention. It can be seen that a high-purity metal complex can be obtained in a higher yield when the prepared ligand is used than when a ligand synthesized by a known method is used.

Synthesis Example 3 Synthesis of Metal Complex C-1
Step 1: Synthesis of ligand (method of the present invention)

  A 100 ml three-headed flask is charged with a solution of 3.17 g (20 mmol) of 3-methylphenanthridine-6-amine in 50 ml of toluene, 6.21 g (30 mmol) of 1-bromo-2-octanone, 3.04 g (30 mmol) of triethylamine, and 140 The mixture was reacted for 3 hours under reflux with heating in an oil bath at 0 ° C. The reaction was completed after confirming the disappearance of the raw materials by thin layer chromatography.

  The reaction solution was filtered to remove insolubles, and then concentrated under reduced pressure until the volume was reduced to about half. The solution was purified by column gel chromatography (hexane-tetrahydrofuran = 10: 1 to 2: 1) to give 5.70 g of 2-n-hexyl-6-methylimidazo [1,2, f] phenanthridine (yield). 90%).

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.0%.

  Step 2: Synthesis of metal complex C

  In a 50 ml four-necked flask, 1.22 g (2.5 mmol) of trisacetylacetonatoiridium complex, 3.96 g of 2-n-hexyl-6-methylimidazo [1,2, f] phenanthridine, tridecane 10 Drops were added, and a nitrogen blowing tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 1.45 g of crude crystals.

  After the crystals were purified by column chromatography (developing solvent: toluene / ethyl acetate), the obtained crystals were heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, and then filtered to obtain 1.30 g (45.7%) of metal complex C. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.2%.

Synthesis Comparative Example 3: Synthesis of metal complex C-2
Step 1: Synthesis of ligand (method described in US Pat. No. 2,070,190,359)

  In a 100 ml three-headed flask, a solution of 3-methylphenanthridine-6-amine 8.34 g (40 mmol) in 2-propanol 200 ml, 1-bromo-2-octanone 12.42 g (60 mmol), sodium carbonate 9.54 g (90 mmol) The mixture was reacted for 24 hours under reflux at an internal temperature of 80 ° C. The reaction was completed after confirming the disappearance of the raw materials by thin layer chromatography.

  The reaction solution was concentrated under reduced pressure to completely remove the solvent, and then purified by silica gel column chromatography (hexane-tetrahydrofuran = 10: 1 to 2: 1) to obtain 2-n-hexyl-6-methylimidazo [1,2 , F] Phenanthridine (6.33 g, yield 50%) was obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 85.0%.

  Since the purity was low, chromatographic purification by a recycle GPC method using tetrahydrofuran as an eluent was performed. The product was split in half and half was purified.

  Since high molecular weight components that were difficult to confirm by thin layer chromatography were included, recycle purification was performed several times to remove high molecular weight components.

  The recovered target product was 2.70 g (yield 42.7% [converted]).

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) improved to 98.5%.

  Step 2: Synthesis of metal complex C

2-1: Synthesis using low-purity ligand A metal complex was synthesized using a ligand (HPLC purity was 85.0%) that had been purified only by Sicagel column chromatography.

  In a 50 ml four-necked flask, 0.73 g (1.5 mmol) of trisacetylacetonatoiridium complex, 2.37 g of 2-n-hexyl-6-methylimidazo [1,2, f] phenanthridine, tridecane 10 Drops were added, and a nitrogen blowing tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.75 g of crude crystals.

  After the crystals were purified by column chromatography (developing solvent: toluene / ethyl acetate), the obtained crystals were suspended with heating in a mixed solvent of tetrahydrofuran and ethyl acetate, and then filtered to obtain 0.65 g (38.1%) of metal complex C. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 98.5%.

2-2: Synthesis using a high-purity ligand In addition to purification by Sicagel column chromatography, a metal complex was prepared using a ligand (HPLC purity was 98.5%) that was chromatographically purified by the GPC method. Synthesized.

  In a 50 ml four-necked flask, 0.73 g (1.5 mmol) of trisacetylacetonatoiridium complex, 2.37 g of 2-n-hexyl-6-methylimidazo [1,2, f] phenanthridine, tridecane 10 Drops were added, and a nitrogen blowing tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.85 g of crude crystals.

  The crystal was purified by column chromatography (developing solvent: toluene / ethyl acetate), and the obtained crystal was heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, followed by filtration to obtain 0.74 g (43.3%) of metal complex C. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.0%.

  From the comparison between Synthesis Example 3 and Synthesis Comparative Example 3, in the synthesis of imidazo [1,2-f] phenanthridine having a substituent at the 2-position, the method of the present invention produces a high-purity product in high yield. On the other hand, in the known method, the yield is lowered and the purity of the product obtained by silica gel column chromatographic purification is also low. The purity can be increased by chromatographic purification by the GPC method, but the final yield is further reduced.

  From the comparison between Synthesis Example 3 and Synthesis Comparative Example 3, synthesis of a metal complex having a ligand of imidazo [1,2-f] phenanthridine having a substituent at the 2-position is also synthesized by the method of the present invention. It can be seen that a high-purity metal complex can be obtained in a higher yield when the prepared ligand is used than when a ligand synthesized by a known method is used.

Synthesis Example 4 Synthesis of Metal Complex D-1
Step 1: Synthesis of ligand (method of the present invention)

  A 100 ml three-headed flask is charged with a solution of 3-methylphenanthridine-6-amine 4.17 g (20 mmol) in toluene, 2-bromo-2-mesityl-acetophenone 7.23 g (30 mmol), and triethylamine 3.04 g (30 mmol). The mixture was reacted for 3 hours under reflux with heating in an oil bath at 140 ° C. The reaction was completed after confirming the disappearance of the raw materials by thin layer chromatography.

  The reaction solution was filtered to remove insolubles, and then concentrated under reduced pressure until the volume was reduced to about half. The solution was purified by column gel chromatography (hexane-tetrahydrofuran = 10: 1 to 2: 1) to give 6.45 g of 3-mesityl-7-methylimidazo [1,2, f] phenanthridine (yield 92%). )

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.0%.

  Step 2: Synthesis of metal complex D

  In a 50 ml four-necked flask, 1.22 g (2.5 mmol) of trisacetylacetonatoiridium complex, 4.38 g of 3-mesityl-7-methylimidazo [1,2, f] phenanthridine, 10 drops of tridecane. It was set on an oil bath stirrer with a nitrogen blowing tube, a thermometer, and an air cooling tube. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 1.63 g of crude crystals.

  After the crystals were purified by column chromatography (developing solvent: toluene / ethyl acetate), the obtained crystals were heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, and then filtered to obtain 1.50 g (48.4%) of metal complex D. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.3%.

Synthesis Comparative Example 4: Synthesis of metal complex D-2
Step 1: Synthesis of ligand (method described in US Pat. No. 2,070,190,359)

  In a 100 ml three-headed flask, a solution of 3-methylphenanthridine-6-amine 8.34 g (40 mmol) in 2-propanol 200 ml, 2-bromo-2-mesityl-acetophenone 14.47 g (60 mmol), sodium carbonate 9.54 g (90 mmol) ) And reacted under reflux at an internal temperature of 80 ° C. for 24 hours. The reaction was completed after confirming the disappearance of the raw materials by thin layer chromatography.

  The reaction solution was concentrated under reduced pressure to completely remove the solvent, and then purified by silica gel column chromatography (hexane-tetrahydrofuran = 10: 1 to 2: 1) to obtain 3-mesityl-7-methylimidazo [1,2, f ] 5.89 g (42% yield) of phenanthridine was obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 84.0%.

  Since the purity was low, chromatographic purification by a recycle GPC method using tetrahydrofuran as an eluent was performed. The product was split in half and half was purified.

  Since high molecular weight components that were difficult to confirm by thin layer chromatography were included, recycle purification was performed several times to remove high molecular weight components.

  The recovered target product was 2.44 g (yield 34.8% [converted]).

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) improved to 98.7%.

  Step 2: Synthesis of metal complex D

2-1: Synthesis Using Low-Purity Ligands A metal complex was synthesized using a ligand (HPLC purity was 84.0%) that had been purified only by silica gel column chromatography.

  In a 50 ml four-necked flask, 0.73 g (1.5 mmol) of trisacetylacetonatoiridium complex, 2.63 g of 3-mesityl-7-methylimidazo [1,2, f] phenanthridine, and 10 drops of tridecane are added. It was set on an oil bath stirrer with a nitrogen blowing tube, a thermometer, and an air cooling tube. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.74 g of crude crystals.

  After the crystals were purified by column chromatography (developing solvent toluene / ethyl acetate), the obtained crystals were heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, filtered, and 0.64 g (34.4%) of metal complex C was filtered. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 98.6%.

2-2: Synthesis using a high-purity ligand In addition to purification by Sicagel column chromatography, a metal complex was prepared using a ligand (HPLC purity was 98.7%) that was chromatographically purified by the GPC method. Synthesized.

  In a 50 ml four-necked flask, 0.73 g (1.5 mmol) of trisacetylacetonatoiridium complex, 2.37 g of 2-n-hexyl-6-methylimidazo [1,2, f] phenanthridine, tridecane 10 Drops were added, and a nitrogen blowing tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. In a nitrogen atmosphere, the reaction was conducted by heating and stirring in an oil bath at 240 ° C. for 20 hours.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 0.89 g of crude crystals.

  The crystal was purified by column chromatography (developing solvent: toluene / ethyl acetate), and the obtained crystal was heated and suspended in a mixed solvent of tetrahydrofuran and ethyl acetate, followed by filtration to obtain 0.79 g (42.5%) of metal complex C. )Obtained.

The purity measured by HPLC analysis (ODS-2: tetrahydrofuran-H ₂ O = 20: 80) was 99.0%.

  From the comparison between Synthesis Example 4 and Synthesis Comparative Example 4, in the synthesis of imidazo [1,2-f] phenanthridine having a substituent at the 3-position, the method of the present invention produces a high-purity product in high yield. On the other hand, in the known method, the yield is lowered and the purity of the product obtained by silica gel column chromatographic purification is also low. The purity can be increased by chromatographic purification by the GPC method, but the final yield is further reduced.

  From the comparison between Synthesis Example 4 and Synthesis Comparative Example 4, synthesis of a metal complex having imidazo [1,2-f] phenanthridine having a substituent at the 3-position as a ligand is also synthesized by the method of the present invention. It can be seen that a high-purity metal complex can be obtained in a higher yield when the prepared ligand is used than when a ligand synthesized by a known method is used.

  Synthesis Example 5 to Synthesis Example 6, Synthesis Comparison Example 5 to Synthesis Comparison Example 6: Metal Complex E to Metal Complex F were synthesized in the same manner as in the above Examples and Comparative Examples.

  The synthesis route is shown below, and only the reaction conditions, yield and purity are summarized in Tables 1 and 2 together with Synthesis Examples 1 to 4 and Synthesis Comparative Examples 1 to 4.

  Although not included in the scope of the present invention, the reaction conditions (most constituent elements) are the same as those of the present invention, but the effects of the invention are different from those of the prior art. A configuration example in which no appears is described as a reference example (the same applies to other tables).

Synthesis Example 5 and Synthesis Comparative Example 5
Step1: Synthesis of ligand

  Step 2: Synthesis of metal complex E

Synthesis Example 6 and Synthesis Comparative Example 6
Step1: Synthesis of ligand

  Step 2: Synthesis of metal complex F

  From the comparison between Synthesis Examples 5 and 6 and Synthesis Comparative Examples 5 and 6, in the synthesis of imidazo [1,2-f] phenanthridine having a substituent at the 2- and 3-positions, the method of the present invention produces high purity. The product can be obtained in a high yield, whereas in the known method, the yield is also lowered, and the purity of the product obtained by silica gel column chromatographic purification is also low. The purity can be increased by chromatographic purification by the GPC method, but the final yield is further reduced.

  From the comparison between Synthesis Examples 5 and 6 and Synthesis Comparative Examples 5 and 6, in the synthesis of a metal complex having an imidazo [1,2-f] phenanthridine having a substituent at the 2,3-position as a ligand, It can be seen that the use of the ligand synthesized by the method of the present invention provides a high-purity metal complex in a higher yield than that using a ligand synthesized by a known method.

  Below, the synthesis method of the present invention is applied to the synthesis of imidazole compounds represented by the general formulas (4), (6), (8), and (10) other than imidazo [1,2-f] phenanthridine. An example is shown. In addition, the synthesis of metal complexes G to J using the synthesized compound as a ligand is also shown.

  Synthetic Example 7 to Synthetic Example 10, Synthetic Comparative Example 7 to Synthetic Comparative Example 10: Ligand and Metal Complex G to Metal Complex J in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6 above. Was synthesized. The synthesis route is shown below, and only the results of reaction conditions, yield and purity are summarized in Tables 3 and 4.

Synthesis Example 7 and Synthesis Comparative Example 7
Step1: Synthesis of ligand

  Step 2: Synthesis of metal complex G

Synthesis Example 8 and Synthesis Comparative Example 8
Step1: Synthesis of ligand

  Step 2: Synthesis of metal complex H

Synthesis Example 9 and Synthesis Comparative Example 9
Step1: Synthesis of ligand

  Step 2: Synthesis of metal complex I

Synthesis Example 10 and Synthesis Comparative Example 10
Step1: Synthesis of ligand

  Step 2: Synthesis of metal complex J

  From the comparison of Synthesis Examples 7 to 10 and Synthesis Comparative Examples 7 to 10, the method of the present invention can be applied to the synthesis of imidazole compounds represented by the general formulas (4), (6), (8), and (10). A product having a high purity can be obtained in a high yield, whereas in the known method, the yield is also lowered, and the purity of the product obtained by silica gel column chromatography purification is also low. The purity can be increased by chromatographic purification by the GPC method, but the final yield is further reduced.

  From the comparison between Synthesis Examples 7 to 10 and Synthesis Comparative Examples 7 to 10, synthesis of metal complexes having imidazole compounds represented by the general formulas (4), (6), (8), and (10) as ligands. However, it can be seen that a high-purity metal complex can be obtained in a higher yield when using the ligand synthesized by the method of the present invention than when using a ligand synthesized by a known method. .

  Next, an organic electroluminescent element is produced using the metal complex manufactured using the ligand manufactured by the manufacturing method of this invention, and the effect of this invention is demonstrated.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

  Below, the structure of the compound used in an Example is shown below.

Example 1
<< Production of Organic EL Element 1-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of α-NPD was put in a molybdenum resistance heating boat, and 200 mg of H-1 as a host compound was put in another molybdenum resistance heating boat, Another molybdenum resistance heating boat was charged with 200 mg of BAlq, another molybdenum resistance heating boat was charged with 100 mg of Firpic, and another molybdenum resistance heating boat was charged with 200 mg of Alq ₃ and attached to a vacuum deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was heated by heating, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / sec. The hole transport layer was provided.

  Further, the heating boat containing H-1 and Ferric was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively, to obtain a film thickness of 40 nm. The light emitting layer was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing BAlq was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer.

In addition, the heating boat containing Alq ₃ is further energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further provide an electron transport layer having a thickness of 40 nm. It was. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the organic EL element 1-1 was produced.

<< Production of Organic EL Elements 1-2 to 1-21 >>
In the production of the organic EL device 1-1, the organic EL devices 1-2 to 1- 1 were prepared in the same manner except that H-1 as the host compound of the light-emitting layer and Firpic as the dopant compound were replaced with the compounds shown in Table 5. 21 was produced.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements 1-1 to 1-21, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the periphery, and this is placed on the cathode so as to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 3 and 4 was formed and evaluated.

  FIG. 3 is a schematic diagram of the lighting device, and the organic EL element 101 is covered with a glass cover 102 (in addition, the sealing operation with the glass cover is performed in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. (In a high purity nitrogen gas atmosphere with a purity of 99.999% or more).

  4 shows a cross-sectional view of the lighting device. In FIG. 4, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

(External quantum efficiency)
By lighting the organic EL element under a constant current condition of room temperature (about 23 to 25 ° C.) and ^2.5 mA / cm ² , and measuring the light emission luminance (L) [cd / m ² ] immediately after the start of lighting, The external extraction quantum efficiency (η) was calculated. Here, CS-1000 (manufactured by Konica Minolta Sensing) was used for measurement of light emission luminance.

  The external extraction quantum efficiency was expressed as a relative value with the organic EL element 1-1 as 100.

(Half life)
The half-life was evaluated according to the measurement method shown below.

Each organic EL device driven with a constant current at a current giving an initial luminance 1000 cd / ^{m 2,} obtains the time to be 1/2 (500cd / ^{m 2)} of the initial luminance, which was used as a measure of the half-life.

  The half life was expressed as a relative value when the comparative organic EL element 1-1 was set to 100.

(Initial deterioration)
The initial deterioration was evaluated according to the measurement method shown below.

When the half-life was measured, the time required for the luminance to reach 90% was measured and used as a measure of initial deterioration. The initial deterioration was 100 for the comparative organic EL element 1-1. The initial deterioration was calculated based on the following formula.
Initial deterioration = (luminance 90% arrival time of organic EL element 1-1) / (luminance 90% arrival time of each element) × 100
That is, the smaller the initial deterioration value is, the smaller the initial deterioration is.

(Dark spot)
The light emitting surface when each organic EL element was continuously lit under a constant current condition of ^2.5 mA / cm ² at room temperature was visually evaluated. When the number of people who confirmed dark spots in each element after 10 hours of continuous lighting by visual evaluation by 10 randomly selected people was 5 or more: ×
When the number of confirmed dark spots is 1-4: △
When the number of confirmed dark spots is 0: ○
It was.

  The above evaluation results are shown in Table 5.

  From Table 5, it can be seen that the organic EL device of the present invention has less initial luminance degradation and a longer life as a result, compared to the comparative device. It can also be seen that the generation of dark spots is suppressed. That is, a device manufactured using a metal complex manufactured using a ligand manufactured by the manufacturing method of the present invention is a comparison manufactured using a ligand manufactured by a manufacturing method that does not depend on the manufacturing method of the present invention. It is clear that the device exhibits superior performance as compared with the device.

Example 2
<< Preparation of White Light Emitting Element and White Lighting Device-1 >>
<< Preparation of Organic EL Element 2-1 >>
The electrode of the transparent electrode substrate of Example 1 was patterned to 50 mm × 50 mm, and α-NPD was formed as a hole injection / transport layer with a thickness of 25 nm thereon as in Example 1, and further H— The heating boat containing 4 and the boat containing Irpic and the boat containing Ir-9 are energized independently, and the deposition rates of H-4 as a light-emitting host and Irpic as a light-emitting dopant and Ir-9 are increased. It adjusted so that it might be set to 100: 5: 0.6, it vapor-deposited so that it might become a film thickness of 30 nm, and the light emitting layer was provided.

Next, 10 nm of BAlq was deposited to provide a hole blocking layer. Furthermore, it was deposited Alq ₃ at 40nm an electron transporting layer.

  Next, as in Example 1, a square perforated mask having the same shape as the transparent electrode made of stainless steel was placed on the electron transport layer, and lithium fluoride 0.5 nm as the cathode buffer layer and aluminum 150 nm as the cathode. The white light emitting organic EL element 2-1 was produced by vapor deposition and film formation.

  This element was provided with a sealing can having the same method and the same structure as in Example 1, and a flat lamp as shown in FIGS. 3 and 4 was produced. When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

<< Production of Organic EL Elements 2-2 to 2-15 >>
In the production of the organic EL device 2-1, the organic EL devices 1-2 to 2-2 were prepared in the same manner except that H-4, which is a host compound of the light-emitting layer, and Firpic, which is a dopant compound, were replaced with compounds shown in Table 6. 15 was produced.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements 2-1 to 2-15, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the periphery, and this is placed on the cathode so as to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 3 and 4 was formed and evaluated.

  FIG. 3 is a schematic diagram of the lighting device, and the organic EL element 101 is covered with a glass cover 102 (in addition, the sealing operation with the glass cover is performed in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. (In a high purity nitrogen gas atmosphere with a purity of 99.999% or more).

  4 shows a cross-sectional view of the lighting device. In FIG. 4, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

(External quantum efficiency)
By lighting the organic EL element under a constant current condition of room temperature (about 23 to 25 ° C.) and ^2.5 mA / cm ² , and measuring the light emission luminance (L) [cd / m ² ] immediately after the start of lighting, The external extraction quantum efficiency (η) was calculated. Here, CS-1000 (manufactured by Konica Minolta Sensing) was used for measurement of light emission luminance.

  The external extraction quantum efficiency was expressed as a relative value with the organic EL element 2-1 being 100.

(Half life)
The half-life was evaluated according to the measurement method shown below.

Each organic EL device driven with a constant current at a current giving an initial luminance 1000 cd / ^{m 2,} obtains the time to be 1/2 (500cd / ^{m 2)} of the initial luminance, which was used as a measure of the half-life.

  The half life was expressed as a relative value when the comparative organic EL element 2-1 was set to 100.

(Initial deterioration)
+ Initial degradation was evaluated according to the measurement method shown below.

When the half-life was measured, the time required for the luminance to reach 90% was measured and used as a measure of initial deterioration. The initial deterioration was 100 for the comparative organic EL element 2-1. The initial deterioration was calculated based on the following formula.
Initial deterioration = (luminance 90% arrival time of organic EL element 1-1) / (luminance 90% arrival time of each element) × 100
That is, the smaller the initial deterioration value is, the smaller the initial deterioration is.

(Dark spot)
The light emitting surface when each organic EL element was continuously lit under a constant current condition of ^2.5 mA / cm ² at room temperature was visually evaluated. When the number of people who confirmed dark spots in each element after 10 hours of continuous lighting by visual evaluation by 10 randomly selected people was 5 or more: ×
When the number of confirmed dark spots is 1-4: △
When the number of confirmed dark spots is 0: ○
It was.

  The above evaluation results are shown in Table 6.

  From Table 6, it can be seen that the organic EL element of the present invention has less initial luminance degradation and a longer life as a result, compared to the comparative element. It can also be seen that the generation of dark spots is suppressed. That is, a device manufactured using a metal complex manufactured using a ligand manufactured by the manufacturing method of the present invention is a comparison manufactured using a ligand manufactured by a manufacturing method that does not depend on the manufacturing method of the present invention. It is clear that the device exhibits superior performance as compared with the device.

Example 3
<< Production of White Light Emitting Element and White Lighting Device-2 >>
<< Production of Organic EL Element 3-1 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After the film formation by spin coating, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of compound A dissolved in 10 ml of toluene was formed on the first hole transport layer by spin coating at 1000 rpm for 30 seconds. After irradiating with ultraviolet light for 180 seconds to carry out photopolymerization / crosslinking, vacuum drying was performed at 60 ° C. for 1 hour to form a second hole transport layer.

  Next, a film in which Compound B (60 mg), Firpic (3.0 mg), and Ir-14 (3.0 mg) were dissolved in 6 ml of toluene was used, and a film was formed by a spin coating method at 1000 rpm for 30 seconds. Irradiated with ultraviolet light for 15 seconds to cause photopolymerization / crosslinking, and further heated in vacuum at 150 ° C. for 1 hour to obtain a light emitting layer.

  Further, a solution of compound C (20 mg) dissolved in 6 ml of toluene was used to form a film by spin coating under conditions of 1000 rpm and 30 seconds. Ultraviolet light was irradiated for 15 seconds, photopolymerization / crosslinking was performed, and further heating was performed in vacuum at 80 ° C. for 1 hour to form a hole blocking layer.

Subsequently, this substrate was fixed to a substrate holder of a vacuum vapor deposition apparatus, and 200 mg of Alq ₃ was put into a molybdenum resistance heating boat and attached to the vacuum vapor deposition apparatus. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, energizing and heating the heating boat containing Alq ₃ , depositing on the hole blocking layer at a deposition rate of 0.1 nm / second, An electron transport layer having a thickness of 40 nm was provided.

  In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the white light emission organic EL element 3-1 was produced.

  This element was provided with a sealing can having the same method and the same structure as in Example 1, and a flat lamp as shown in FIGS. 3 and 4 was produced.

  When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

<< Production of Organic EL Elements 3-2 to 3-15 >>
In the production of the organic EL element 2-1, the organic EL elements 3-2 to 3-15 were similarly performed except that the compound B as the host compound of the light emitting layer and the dopant as the dopant compound were replaced with the compounds shown in Table 7. Was made.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements 3-1 to 3-15, the non-light-emitting surface of each organic EL element after production is covered with a glass case, and a glass substrate having a thickness of 300 μm is used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the periphery, and this is placed on the cathode so as to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 3 and 4 was formed and evaluated.

  FIG. 3 is a schematic diagram of the lighting device, and the organic EL element 101 is covered with a glass cover 102 (in addition, the sealing operation with the glass cover is performed in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. (In a high purity nitrogen gas atmosphere with a purity of 99.999% or more).

  4 shows a cross-sectional view of the lighting device. In FIG. 4, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

(External quantum efficiency)
By lighting the organic EL element under a constant current condition of room temperature (about 23 to 25 ° C.) and ^2.5 mA / cm ² , and measuring the light emission luminance (L) [cd / m ² ] immediately after the start of lighting, The external extraction quantum efficiency (η) was calculated. Here, CS-1000 (manufactured by Konica Minolta Sensing) was used for measurement of light emission luminance.

  The external extraction quantum efficiency was expressed as a relative value with the organic EL element 3-1 as 100.

(Half life)
The half-life was evaluated according to the measurement method shown below.

Each organic EL device driven with a constant current at a current giving an initial luminance 1000 cd / ^{m 2,} obtains the time to be 1/2 (500cd / ^{m 2)} of the initial luminance, which was used as a measure of the half-life.

  The half-life was expressed as a relative value when the comparative organic EL element 3-1 was set to 100.

(Initial deterioration)
The initial deterioration was evaluated according to the measurement method shown below.

  When the half-life was measured, the time required for the luminance to reach 90% was measured and used as a measure of initial deterioration.

The initial deterioration was 100 for the comparative organic EL element 3-1. The initial deterioration was calculated based on the following formula.
Initial deterioration = (luminance 90% arrival time of organic EL element 1-1) / (luminance 90% arrival time of each element) × 100
That is, the smaller the initial deterioration value is, the smaller the initial deterioration is.

(Dark spot)
The light emitting surface when each organic EL element was continuously lit under a constant current condition of ^2.5 mA / cm ² at room temperature was visually evaluated. When the number of people who confirmed dark spots in each element after 10 hours of continuous lighting by visual evaluation by 10 randomly selected people was 5 or more: ×
When the number of confirmed dark spots is 1-4: △
When the number of confirmed dark spots is 0: ○
It was.

  The above evaluation results are shown in Table 7.

  From Table 7, it can be seen that the organic EL element of the present invention has less initial luminance deterioration and a longer life as a result, compared to the comparative element. It can also be seen that the generation of dark spots is suppressed. That is, a device manufactured using a metal complex manufactured using a ligand manufactured by the manufacturing method of the present invention is a comparison manufactured using a ligand manufactured by a manufacturing method that does not depend on the manufacturing method of the present invention. It is clear that the device exhibits superior performance as compared with the device.

Example 4
<< Preparation of Organic EL Element 4-1 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After the film formation by spin coating, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of compound A dissolved in 10 ml of toluene was formed on the first hole transport layer by spin coating at 1000 rpm for 30 seconds.

  After irradiating with ultraviolet light for 180 seconds to carry out photopolymerization / crosslinking, vacuum drying was performed at 60 ° C. for 1 hour to form a second hole transport layer.

  Next, using a solution obtained by dissolving Compound B (60 mg) and Firpic (3.0 mg) in 6 ml of toluene, a film was formed by spin coating under conditions of 1000 rpm and 30 seconds to form a light emitting layer.

  Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, 200 mg of BAlq was put into a molybdenum resistance heating boat, and attached to the vacuum deposition apparatus.

After the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, the heating boat containing BAlq was energized and heated, deposited on the light emitting layer at a deposition rate of 0.1 nm / second, and a film thickness of 40 nm. The electron transport layer was provided.

  In addition, the substrate temperature at the time of vapor deposition was room temperature. Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the organic EL element 4-1 was produced.

<< Production of Organic EL Elements 4-2 to 4-21 >>
In the production of the organic EL element 4-1, the organic EL elements 4-2 to 4-21 were similarly performed except that the compound B as the host compound in the light emitting layer and the dopant as the dopant compound were replaced with the compounds shown in Table 8. Was made.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements 4-1 to 4-21, the non-light emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the periphery, and this is placed on the cathode so as to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 3 and 4 was formed and evaluated.

  FIG. 3 is a schematic diagram of the lighting device, and the organic EL element 101 is covered with a glass cover 102 (in addition, the sealing operation with the glass cover is performed in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. (In a high purity nitrogen gas atmosphere with a purity of 99.999% or more).

  4 shows a cross-sectional view of the lighting device. In FIG. 4, reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

(External quantum efficiency)
By lighting the organic EL element under a constant current condition of room temperature (about 23 to 25 ° C.) and ^2.5 mA / cm ² , and measuring the light emission luminance (L) [cd / m ² ] immediately after the start of lighting, The external extraction quantum efficiency (η) was calculated.

  Here, CS-1000 (manufactured by Konica Minolta Sensing) was used for measurement of light emission luminance.

  The external extraction quantum efficiency was expressed as a relative value with the organic EL element 4-1 as 100.

(Half life)
The half-life was evaluated according to the measurement method shown below. Each organic EL device driven with a constant current at a current giving an initial luminance 1000 cd / ^{m 2,} obtains the time to be 1/2 (500cd / ^{m 2)} of the initial luminance, which was used as a measure of the half-life.

  The half life was expressed as a relative value with the organic EL element 4-1 as 100.

(Initial deterioration)
The initial deterioration was evaluated according to the measurement method shown below.

  At the time of measuring the half-life, a time for 90% of the initial luminance was obtained and used as a measure of initial deterioration.

The initial degradation was expressed as a relative value with the organic EL element 4-1 as 100. The initial deterioration was calculated based on the following formula.
Initial degradation = (90% reach time of luminance of organic EL element 4-1) / (90% reach time of brightness of each element) × 100
That is, the smaller the initial deterioration value is, the smaller the initial deterioration is.

(Dark spot)
The light emitting surface when the organic EL element was continuously lit under a constant current condition of ^2.5 mA / cm ² at room temperature was visually evaluated. When the number of people who confirmed dark spots by visual evaluation by 10 randomly selected people is 5 or more: ×
When the number of confirmed dark spots is 1-4: △
When the number of confirmed dark spots is 0: ○
It was.

  The above evaluation results are shown in Table 8.

  From Table 8, it can be seen that the organic EL element of the present invention has less initial luminance deterioration and a longer life as a result, compared to the comparative element. It can also be seen that the generation of dark spots is suppressed. That is, a device manufactured using a metal complex manufactured using a ligand manufactured by the manufacturing method of the present invention is a comparison manufactured using a ligand manufactured by a manufacturing method that does not depend on the manufacturing method of the present invention. It is clear that the device exhibits superior performance as compared with the device.

Schematic diagram showing an example of a display device composed of organic EL elements Schematic diagram of the display unit Schematic of lighting device Cross section of the lighting device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line A Display part B Control part 101 Organic EL element 107 Glass substrate with a transparent electrode 106 Organic EL layer 105 Cathode 102 Glass cover 108 Nitrogen gas 109 Water catching agent

Claims (10)

A method for producing an imidazole compound represented by the following general formula (4), (6), (8) or (10),
A compound represented by the following general formula (5), (7), (9) or (11) and a compound represented by the following general formula (3) are nonpolar aprotic having a dielectric constant of 10 or less. The manufacturing method of the imidazole compound characterized by making it react in a solvent.

[Wherein, R ₁ and R ₂ each represent a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. E ^{1a to} E ^1k represent a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and E ^1l represents a carbon atom or a nitrogen atom. Each of the rings formed by E ^{1a to} E ^1f and E ^{1g to} E ¹¹ represents a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocyclic ring, and the 6-membered aromatic hydrocarbon ring Is a benzene ring, and the 5-membered or 6-membered aromatic heterocycle is a furan ring, a thiophene ring, an oxazole ring, an imidazole ring, or a pyridine ring. In the imidazole compound represented by the general formula (4), (6), (8) or (10), the skeleton composed of E ^{1a to} E ¹¹ and the imidazole ring has a total of 18π electrons. R ^{1b to} R ^1e and R ^{1h to} R ^1j each represent a hydrogen atom or a substituent. However, when E ^{1 *} to which R ^{1 *} is bonded is an oxygen atom or a sulfur atom, R ^{1 *} does not exist. In addition, when E ^{1 *} to which R ^{1 *} is bonded is a nitrogen atom, R ^{1 *} may not exist. Here, * represents any of the characters b, c, d, e, h, i, and j. In addition, among the compounds represented by the above general formula, the raw material and the product are structurally related to each other. ]

[Wherein, R ₁ and R ₂ each represent a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. X represents a halogen atom. ]   The method for producing an imidazole compound according to claim 1, wherein the nonpolar aprotic solvent is an aromatic compound.   The method for producing an imidazole compound according to claim 1 or 2, wherein the nonpolar aprotic solvent is alkyl-substituted benzene or chloro-substituted benzene.   In addition to the compound represented by the general formula (3) and the compound represented by the general formula (5), (7), (9) or (11), the reaction is performed using an organic base. The manufacturing method of the imidazole compound as described in any one of Claim 1 to 3.   The imidazole compound according to claim 4, wherein the organic base is used in an amount of 1.1 to 1.5 equivalents of the compound represented by the general formula (5), (7), (9) or (11). Production method.   6. The method for producing an imidazole compound according to claim 4, wherein the organic base is a trialkylamine.   The said reaction is performed at 50-200 degreeC, The manufacturing method of the imidazole compound as described in any one of Claim 1 to 6 characterized by the above-mentioned.   The said reaction is performed at 100-150 degreeC, The manufacturing method of the imidazole compound as described in any one of Claim 1 to 7 characterized by the above-mentioned.   X is bromine or chlorine, The manufacturing method of the imidazole compound as described in any one of Claim 1 to 8 characterized by the above-mentioned. A method for producing an imidazole compound represented by the following general formula (1),
The compound represented by the following general formula (2) and the compound represented by the following general formula (3) are reacted in the nonpolar aprotic solvent. A method for producing the imidazole compound according to claim 1.

[Wherein, R _{1 to} R ₉ each represents a hydrogen atom or a substituent. R ₁ and R ₂ are not both hydrogen. X represents a halogen atom. ]

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