Method for producing an organometallic complex

Abstract

Provided is a production method which makes it possible to produce an organic metal complex with high yield. This method for producing an organic metal complex comprises reacting a dinuclear complex containing a cyano group represented by general formula (Gp) with a β-diketone represented by general formula (L1) in the presence of an aprotic solvent having a boiling point of 80℃ or higher and a base. (In the formulae, A1 to A4 independently represent a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; R1 to R6 independently represent any one of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms; and R7 to R11 independently represent any one of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, in which at least one of R7 to R11 represents a cyano group.)

Description

Technical Field

[0001] One aspect of the present invention relates to a method for producing an organometallic complex. In particular, it relates to a method for producing an organometallic complex capable of converting energy in the triplet excited state into light emission.

Background Art

[0002] A light-emitting device (also referred to as an organic EL element) having an organic compound as a light-emitting substance between a pair of electrodes has characteristics such as being thin, lightweight, having a high-speed response, and being driven at a low voltage. Therefore, development related to displays applying this has been advanced in various fields. When a voltage is applied to this light-emitting device, electrons and holes injected from the electrodes recombine, whereby the light-emitting substance becomes an excited state and emits light when the excited state returns to the ground state. Note that as types of excited states, there are a singlet excited state (S * ) and a triplet excited state (T * ), and light emission from the singlet excited state is called fluorescence, and light emission from the triplet excited state is called phosphorescence. Also, the statistical generation ratio of these in the light-emitting device is considered to be S * :T * = 1:3.

[0003] Among the above light-emitting substances, a compound capable of converting energy in the singlet excited state into light emission is called a fluorescent compound (fluorescent material), and a compound capable of converting energy in the triplet excited state into light emission is called a phosphorescent compound (phosphorescent material).

[0004] Therefore, based on the above generation ratio, the theoretical limit of the internal quantum efficiency (the ratio of photons generated with respect to injected carriers) in a light-emitting device using each of the above light-emitting substances is 25% when using a fluorescent material and 75% when using a phosphorescent material.

[0005] That is, compared with a light-emitting device using a fluorescent material, a light-emitting device using a phosphorescent material can achieve higher efficiency. Therefore, in recent years, the development of various types of phosphorescent materials has been actively carried out. In particular, organometallic complexes having iridium or the like as a central metal have attracted attention in terms of practical application (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Although the development of phosphorescent materials showing excellent properties as reported in the above-mentioned Patent Document 1 has been progressing, a technique for manufacturing them with a higher yield is desired.

[0008] Therefore, in one aspect of the present invention, a novel method for manufacturing an organometallic complex is provided. In another aspect of the present invention, a manufacturing method for obtaining an organometallic complex with a high yield is provided. Note that the description of these problems does not prevent the existence of other problems. Also, one aspect of the present invention does not necessarily need to solve all of these problems. Further, other problems will be naturally apparent from the description in the specification, drawings, claims, etc., and it is possible to extract these other problems from the description in the specification, drawings, claims, etc.

Means for Solving the Problems

[0009] One aspect of the present invention is a method for manufacturing an organometallic complex, which comprises reacting a polynuclear complex containing a cyano group crosslinked with chlorine and a β-diketone in the presence of an aprotic solvent having a boiling point of 80°C or higher and a base. In particular, as the aprotic solvent, an ether-based solvent, a nitrile-based solvent, an amide-based solvent, etc. are preferable.

[0010] Another aspect of the present invention is a method for producing an organometallic complex by reacting a polynuclear complex containing a cyano group crosslinked with chlorine and a β-diketone in the presence of an amide compound having a boiling point of 80 °C or higher and a base. In particular, as the amide compound, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone and the like are preferable.

[0011] In the above configuration, the polynuclear complex preferably has pyrazine. Further, in the above configuration, the polynuclear complex preferably has pyrazine and the central metal is iridium.

[0012] Another aspect of the present invention is a method for producing a cyclometal complex by reacting a polynuclear complex containing a cyano group crosslinked with chlorine and a β-diketone in the presence of an aprotic solvent having a boiling point of 80 °C or higher and a base. In particular, as the aprotic solvent, ether solvents, nitrile solvents, amide solvents and the like are preferable.

[0013] Another aspect of the present invention is a method for producing a cyclometal complex by reacting a polynuclear complex containing a cyano group crosslinked with chlorine and a β-diketone in the presence of an amide compound having a boiling point of 80 °C or higher and a base. In particular, as the amide compound, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone and the like are preferable.

[0014] In the above configuration, the polynuclear complex preferably has pyrazine.

[0015] Another aspect of the present invention is a method for producing an organometallic complex by reacting a polynuclear complex containing a cyano group represented by the general formula (Gp) and a β-diketone represented by the general formula (L1) in the presence of an aprotic solvent having a boiling point of 80 °C or higher and a base.

[0016]

Chemical formula

[0017] In the above general formula (Gp), A1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group. Further, in the general formula (L1), R 20 ~R 22 each independently represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms.

[0018] Another aspect of the present invention is a method for producing an organometallic complex in which a polynuclear complex containing a cyano group represented by the general formula (Gp) and a β-diketone represented by the general formula (L1) are reacted in the presence of an amide compound and a base having a boiling point of 80°C or higher.

[0019]

Chemical formula

[0020] In the above general formula (Gp), A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R 7 ~R11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group. Further, in general formula (L1), R 20 ~R 22 each independently represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms.

[0021] Further, by the above production method which is one aspect of the present invention, for example, an organometallic complex represented by the following general formula (G1) can be obtained.

[0022]

Chemical formula

[0023] However, in general formula (G1), A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group. L represents a monoanionic ligand having a β-diketone structure.

[0024] In the above general formula (G1), R 7 ~R 11It is preferable that at least one of them is an alkyl group having 1 to 6 carbon atoms. In particular, in order to prevent the emission spectrum peak from going too far to the long wavelength side and maintain visual sensitivity, R 7 or R 11 It is preferable that at least one of them is an alkyl group having 1 to 6 carbon atoms. That is, this configuration is particularly suitable for obtaining deep red color with high color purity and high efficiency.

[0025] In addition, the organometallic complex represented by the general formula (G1) can emit phosphorescence, that is, emission from the triplet excited state can be obtained and emission can be exhibited. Therefore, by applying it to a light-emitting device, high efficiency can be achieved, which is very effective. Therefore, a light-emitting device using the organometallic complex obtained by the production method which is one aspect of the present invention (for example, used in an EL layer between a pair of electrodes) is included in one aspect of the present invention.

[0026] One aspect of the present invention also includes a light-emitting device having the above light-emitting device, and a lighting device having the light-emitting device in its scope. Therefore, the light-emitting device in this specification refers to an image display device or a light source (including a lighting device). In addition, a module in which a connector, for example, an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) is attached to the light-emitting device, a module in which a printed wiring board is provided at the tip of the TCP, or a module in which an IC (integrated circuit) is directly mounted on the light-emitting device by a COG (Chip On Glass) method are all included in the light-emitting device.

Effects of the Invention

[0027] In one aspect of the present invention, a novel method for producing an organometallic complex can be provided. Further, in one aspect of the present invention, a novel production method capable of obtaining an organometallic complex in a high yield can be provided. Therefore, by using the novel production method of the organometallic complex which is one aspect of the present invention, the production efficiency in mass production etc. can be enhanced. Note that the description of these effects does not prevent the existence of other effects. Also, one aspect of the present invention does not necessarily have to have all of these effects. Further, other effects will be apparent from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc.

Brief Description of Drawings

[0028] FIG. 1A and FIG. 1B are diagrams for explaining the structure of a light-emitting element. FIG. 2A and FIG. 2B are diagrams for explaining the structure of a light-emitting element. FIG. 3 is the 1 1H-NMR chart of the organometallic complex represented by Structural Formula (100). FIG. 4 is a diagram showing the relationship between the heating temperature and the yield.

Embodiments for Carrying Out the Invention

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is possible to variously change its form and details without departing from the spirit and scope of the present invention. Therefore, the present invention is not to be construed as being limited to the description of the embodiments shown below.

[0030] (Embodiment 1) In this embodiment, a method for producing an organometallic complex (synthesis method), which is one aspect of the present invention, will be described. Here, as an example, a method for synthesizing an organometallic complex represented by the following general formula (G1) will be described.

[0031]

Chemical Formula

[0032] ≪Synthesis method of pyrazine derivative represented by general formula (G0)≫ The pyrazine derivative represented by the above general formula (G0) and used for the synthesis of an organometallic complex can be synthesized by the synthesis methods shown in the following three types of synthetic schemes (A1), (A2), and (A3).

[0033]

Chemical formula

[0034] In general formula (G0), A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Also, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group.

[0035] For example, the pyrazine derivative represented by general formula (G0) can be obtained by lithiating a halogenated benzene derivative (a1-1) with an alkyllithium or the like and reacting it with diphenylpyrazine (a2-1) as shown in the following synthetic scheme (A1).

[0036]

Chemical formula

[0037] In the above synthetic scheme (A1), Z represents a halogen, and A 1 ~A4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group.

[0038] In addition, the pyrazine derivative represented by the general formula (G0) can be obtained by coupling a boronic acid (a1-2) of a benzene derivative and a halide (a2-2) of diphenylpyrazine as shown in the following synthesis scheme (A2).

[0039]

Chemical formula

[0040] In the synthesis scheme (A2), X represents a halogen, and A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group.

[0041] In addition, the pyrazine derivative represented by the general formula (G0) can be obtained by reacting a benzene derivative-substituted diketone (a1-3) with a diamine (a2-3) as shown in the following synthesis scheme (A3).

[0042]

Chemical formula

[0043] In the synthesis scheme (A3), A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Also, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group.

[0044] In addition to the above three methods, there are multiple known synthesis methods for the synthesis of the derivative (G0). Therefore, any method can be used.

[0045] Also, since the above compounds (a1-1), (a1-2), (a1-3), (a2-1), (a2-2), and (a2-3) are commercially available in various types or can be synthesized, a large number of types of pyrazine derivatives represented by the general formula (G0) can be synthesized. Therefore, the organometallic complex which is one aspect of the present invention is characterized by having a rich variety of ligand variations.

[0046] ≪Synthesis method of the organometallic complex represented by the general formula (G1)≫ Next, a method for synthesizing an organometallic complex represented by the general formula (G1) is shown. First, as shown in the following synthesis scheme (B-1), a pyrazine derivative represented by the general formula (G0) and an iridium compound containing a halogen (such as iridium chloride, iridium bromide, iridium iodide, etc.) are heated in an inert gas atmosphere without a solvent, or using an alcohol-based solvent (such as glycerol, ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol, etc.) alone, or a mixed solvent of one or more alcohol-based solvents and water, to obtain a dinuclear complex (Gp), which is a kind of organometallic complex having a structure crosslinked by a halogen. There are no particular limitations on the heating means, and an oil bath, a sand bath, an aluminum block, etc. can be used. It is also possible to use microwaves as the heating means.

[0047]

Chemical formula

[0048] In the synthesis scheme (B-1), X represents a halogen, and A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Also, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group.

[0049] Furthermore, as shown in the following synthesis scheme (B-2), by reacting the dinuclear complex (Gp) obtained in the above synthesis scheme (B-1) with β-diketone (HL) in an inert gas atmosphere, the proton of HL is eliminated and L coordinates to the central metal iridium, thereby obtaining an organometallic complex represented by the general formula (G1).

[0050] As the reaction solvent used here, an aprotic solvent is preferable from the viewpoint of yield, and ether solvents such as 1,4-dioxane, anisole, 1,2-dimethoxyethane, and diethylene glycol dimethyl ether, nitrile solvents such as acetonitrile and propionitrile, amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone can be used. Since aprotic solvents prevent the generation of protons more than protic solvents, for example, side reactions such as the elimination of the cyano group due to the reaction of the proton as an electrophilic reagent with the cyano group having a high electron density contained in the organometallic complex can be suppressed. Thereby, the yield in the above reaction can be improved.

[0051] There is no particular limitation on the heating means, and an oil bath, a sand bath, an aluminum block, etc. can be used. It is also possible to use microwaves as the heating means.

[0052] [Chemical formula]

[0053] In the synthesis scheme (B-2), L represents β-diketone from which a proton has been eliminated, X represents a halogen, and A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 1 ~R 6Each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Also, R 7 ~R 11 Each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group.

[0054] Next, an organometallic complex that can be synthesized by the above-described synthesis method will be described.

[0055] The organometallic complex synthesized in this embodiment has iridium as the central metal and a ligand. The ligand has a pyrazine skeleton, and iridium is bonded to the nitrogen at the 1-position of the pyrazine skeleton. Phenyl groups are bonded to the 2-, 3-, and 5-positions of the pyrazine skeleton, and the phenyl groups bonded to the 2- and 3-positions each have an alkyl group as a substituent, and the phenyl group bonded to the 5-position has a cyano group as a substituent.

[0056] Furthermore, the organometallic complex shown in this embodiment has a first ligand and a second ligand that are bonded to iridium as the central metal. The first ligand has a pyrazine skeleton, and iridium is bonded to the nitrogen at the 1-position of the pyrazine skeleton. Phenyl groups are bonded to the 2-, 3-, and 5-positions of the pyrazine skeleton, and the phenyl groups bonded to the 2- and 3-positions each have an alkyl group as a substituent, and the phenyl group bonded to the 5-position has a cyano group as a substituent. The second ligand is a monoanionic bidentate chelate ligand having a β-diketone structure.

[0057] In addition, in the organometallic complex shown in this embodiment, phenyl groups each having an alkyl group as a substituent are bonded to the 2-position and 3-position of the pyrazine skeleton contained in the ligand, and a phenyl group having a cyano group as a substituent is bonded to the 5-position of the pyrazine skeleton. Further, the phenyl group bonded to the 2-position of the pyrazine skeleton is orthometalated to iridium.

[0058] In addition, since the phenyl groups bonded to the 2-position and 3-position of the pyrazine skeleton in the organometallic complex shown in this embodiment each have an alkyl group as a substituent, carbonization due to the reaction between the organometallic complexes during sublimation can be prevented, and the sublimation temperature can be further reduced. Furthermore, by having a cyano group as a substituent of the phenyl group bonded to the 5-position of the pyrazine skeleton, although the sublimation temperature is higher than that in the case of not having a cyano group, the generation of low-molecular-weight decomposition products derived from the above alkyl group, that is, the generation of desorbed gas due to this, can be prevented even when treated at a high temperature during sublimation.

[0059] In addition, since the organometallic complex shown in this embodiment has the effect of shifting the emission spectrum of the organometallic complex to a longer wavelength by having the above cyano group, it has high color purity and exhibits deep red emission. When showing deep red emission, usually, since it also has a spectrum in the near-infrared region, the visibility deteriorates. However, the above alkyl group (the alkyl group possessed by the phenyl groups bonded to the 2-position and 3-position of the pyrazine skeleton) also has the effect of narrowing the emission spectrum, so the decrease in visibility can be suppressed to the maximum extent. Therefore, the above organometallic complex can obtain high efficiency even in deep red with high color purity.

[0060] In the above configuration, it is more preferable that the phenyl group bonded to the 5-position of the pyrazine skeleton has not only a cyano group but also an alkyl group in order to further suppress carbonization due to the reaction between the organometallic complexes. In particular, by having an alkyl group at the 2-position of the phenyl group bonded to the 5-position of the pyrazine skeleton, it is possible to prevent the emission spectrum peak from going too far to a long wavelength and maintain the visibility. That is, it is particularly suitable for obtaining deep red with high color purity and high efficiency.

[0061] The organometallic complex shown in this embodiment is an organometallic complex represented by the following general formula (G1).

[0062]

Chemical formula

[0063] In the general formula (G1), A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Also, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group. L represents a monoanionic ligand having a β-diketone structure.

[0064] The organometallic complex shown in this embodiment is an organometallic complex represented by the following general formula (G2).

[0065]

Chemical formula

[0066] In the general formula (G2), A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 6 represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Also, R 7 ~R 11Each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group. L represents a monoanionic ligand having a β-diketone structure.

[0067] Further, the monoanionic ligand having the β-diketone structure is represented by the following general formula (L1).

[0068]

Chemical formula

[0069] In the general formula (L1), R 71 ~R 73 each independently represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms.

[0070] Further, the organometallic complex shown in this embodiment is an organometallic complex represented by the following general formula (G3).

[0071]

Chemical formula

[0072] In the general formula (G3), A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 1 ~R 6 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R 7 ~R 11represents, independently of each other, any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group. Further, R 71 , R 73 each independently represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms.

[0073] Further, the organometallic complex shown in this embodiment is an organometallic complex represented by the following general formula (G4).

[0074] [Chemical formula]

[0075] In the general formula (G4), A 1 ~A 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R 6 represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R 7 ~R 11 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, and a cyano group, and at least one represents a cyano group. Further, R 71 , R 73 each independently represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms.

[0076] In any of the general formulas (G1) to (G4), when a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms has a substituent, examples of the substituent include alkyl groups having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, and hexyl group, cycloalkyl groups having 5 to 7 carbon atoms such as cyclopentyl group, cyclohexyl group, cycloheptyl group, 1-norbornyl group, and 2-norbornyl group, and aryl groups having 6 to 12 carbon atoms such as phenyl group and biphenyl group.

[0077] Also, A in the general formulas (G1) to (G4) 1 ~A 4 、R 1 ~R 11 Specific examples of the alkyl group having 1 to 6 carbon atoms in any of them include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, neohexyl group, 3-methylpentyl group, 2-methylpentyl group, 2-ethylbutyl group, 1,2-dimethylbutyl group, 2,3-dimethylbutyl group, trifluoromethyl group, and the like.

[0078] Also, A in the general formulas (G1) to (G4) 1 ~A 4 、R 1 ~R 11Specific examples of the aryl group having 6 to 13 carbon atoms in any of them include a phenyl group, a tolyl group (o-tolyl group, m-tolyl group, p-tolyl group), a naphthyl group (1-naphthyl group, 2-naphthyl group), a biphenyl group (biphenyl-2-yl group, biphenyl-3-yl group, biphenyl-4-yl group), a xylyl group, a pentalenyl group, an indenyl group, a fluorenyl group, a phenanthryl group, etc. In addition, the above substituents may be bonded to each other to form a ring. Examples of such cases include, for example, when the 9-position carbon of the fluorenyl group has two phenyl groups as substituents, and the phenyl groups are bonded to each other to form a spirofluorene skeleton.

[0079] In addition, A in the above general formulas (G1) to (G4) 1 ~A 4 , R 1 ~R 11 Specific examples of the heteroaryl group having 3 to 12 carbon atoms in any of them include an imidazolyl group, a pyrazolyl group, a pyridyl group, a pyridazyl group, a triazolyl group, a benzimidazolyl group, a quinolyl group, etc.

[0080] Since the organometallic complex represented by the above general formulas (G1) to (G4) has an alkyl group in A 1 ~A 4 , carbonization due to the reaction between organometallic complexes during sublimation can be prevented, and the sublimation temperature can be further reduced. However, while this alkyl group has such an effect, it slightly generates low-molecular-weight decomposition products during sublimation, which reduces the lifetime of the light-emitting device. In addition, when at least one of R 7 ~R 11 has a cyano group as a substituent of the phenyl group bonded to the 5-position of the pyrazine skeleton, although the sublimation temperature becomes higher compared to the case where it does not have a cyano group, generation of low-molecular-weight decomposition products derived from the above alkyl group, that is, generation of desorbed gas, can be prevented even when treatment is performed at a high temperature during sublimation.

[0081] Therefore, the above organometallic complex is A in the general formulas (G1) to (G4) 1 ~A4 each has an alkyl group as a substituent, and R 7 ~R 11 is characterized in that at least one of them has a cyano group as a substituent. Therefore, when an element is fabricated by vacuum deposition using this organometallic complex, contamination of decomposition products into the element can be suppressed, so that an element having good lifetime characteristics can be obtained.

[0082] In addition, when A 1 ~A 4 does not have an alkyl group as a substituent, even if at least one of R 7 ~R 11 has a cyano group, carbonization due to the reaction between organometallic complexes occurs during sublimation. Therefore, the above organometallic complex has an alkyl group in one of A 1 or A 2 and one of A 3 or A 4 and has a cyano group in at least one of R 7 ~R 11 is a necessary configuration to suppress carbonization due to the reaction between organometallic complexes and the generation of low molecular weight desorbed gas.

[0083] Furthermore, at least one cyano group possessed by R 7 ~R 11 has the effect of shifting the emission spectrum of the organometallic complex to a longer wavelength. That is, the organometallic complex shown in this embodiment has high color purity and exhibits deep red emission. When showing deep red emission, usually, since it also has a spectrum in the near-infrared region, the visual sensitivity deteriorates. However, since the alkyl group introduced into A 1 ~A 4 also has the effect of narrowing the emission spectrum, the decrease in visual sensitivity can be suppressed to the maximum extent. Therefore, the above organometallic complex can obtain high efficiency even in deep red with high color purity.

[0084] In the above general formulas (G1) to (G4), it is more preferable that the phenyl group bonded to the 5-position of the pyrazine skeleton has not only a cyano group but also an alkyl group in order to suppress carbonization due to the reaction between organometallic complexes during sublimation. Therefore, in the above general formulas (G1) to (G4), R 7 ~R 11 is preferably at least one of alkyl groups having 1 to 6 carbon atoms. In particular, when at least one of R 7 or R 11 is an alkyl group having 1 to 6 carbon atoms, it is possible to prevent the emission spectrum peak from going too far to the long wavelength side and maintain the visual sensitivity. That is, in the above organometallic complex, high color purity can be obtained and highly efficient deep red color can be obtained.

[0085] Next, specific structural formulas of the organometallic complexes represented by the above general formulas (G1) to (G4) are shown below. However, the present invention is not limited thereto.

[0086]

Chemical formula

[0087]

Chemical formula

[0088]

Chemical formula

[0089]

Chemical formula

[0090] Note that the organometallic complexes represented by the above structural formulas (100) to (125) are novel substances capable of emitting phosphorescence. Depending on the type of ligand, geometric isomers and stereoisomers may exist for these substances, and all of these isomers are included in the organometallic complexes shown here.

[0091] In addition, since the organometallic complex synthesized by the above-described synthesis method can emit phosphorescence, it can be used as a luminescent substance for a luminescent material or a luminescent device.

[0092] Moreover, by using the organometallic complex produced by the production method which is one aspect of the present invention, a luminescent device, a light-emitting device, an electronic device, or a lighting device with high luminous efficiency can be realized. Also, a luminescent device, a light-emitting device, an electronic device, or a lighting device with low power consumption can be realized.

[0093] The configuration shown in this embodiment can be used in appropriate combination with the configuration shown in other embodiments.

[0094] (Embodiment 2) In this embodiment, a light-emitting device having an EL layer in which an organometallic complex produced by the production method which is one aspect of the present invention can be used will be described with reference to FIG. 1.

[0095] The light-emitting device shown in this embodiment has an EL layer 102 including a light-emitting layer 113 sandwiched between a pair of electrodes (a first electrode (anode) 101 and a second electrode (cathode) 103). The EL layer 102 is formed including, in addition to the light-emitting layer 113, a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, an electron injection layer 115, and the like.

[0096] When a voltage is applied to such a light-emitting device, holes injected from the first electrode 101 side and electrons injected from the second electrode 103 side recombine in the light-emitting layer 113, and due to the energy generated thereby, a luminescent substance such as an organometallic complex contained in the light-emitting layer 113 emits light.

[0097] Note that the hole injection layer 111 in the EL layer 102 is a layer capable of injecting holes into the hole transport layer 112 or the light emitting layer 113. For example, it can be formed of a substance with high hole transportability and an acceptor substance. In this case, holes are generated by electrons being extracted from the substance with high hole transportability by the acceptor substance. Therefore, holes are injected from the hole injection layer 111 through the hole transport layer 112 into the light emitting layer 113. Note that a substance with high hole injectability can also be used for the hole injection layer 111. For example, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. can be used. In addition, phthalocyanine-based compounds such as phthalocyanine (abbreviation: H 2 Pc), copper phthalocyanine (CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) can also be used to form the hole injection layer 111.

[0098] A preferred specific example for manufacturing the light emitting device shown in this embodiment will be described below.

[0099] For the first electrode (anode) 101 and the second electrode (cathode) 103, metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Specifically, indium tin oxide, indium tin oxide containing silicon or silicon oxide, indium zinc oxide, indium oxide containing tungsten oxide and zinc oxide, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), in addition, elements belonging to Group 1 or Group 2 of the periodic table, that is, alkali metals such as lithium (Li) and cesium (Cs), and alkaline earth metals such as calcium (Ca) and strontium (Sr), magnesium (Mg), and alloys containing these (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb) and alloys containing these, and others such as graphene can be used. Note that the first electrode (anode) 101 and the second electrode (cathode) 103 can be formed by, for example, sputtering method, vapor deposition method (including vacuum vapor deposition method), etc.

[0100] As substances with high hole transport properties used for the hole injection layer 111 and the hole transport layer 112, various organic compounds such as aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that the organic compound used for the composite material is preferably an organic compound with high hole transport properties. Specifically, it is preferably a substance having a hole mobility of 1×10 -6 cm 2 / Vs or more. Also, the layer formed using a substance with high hole transport properties may be not only a single layer but also a laminate of two or more layers. Hereinafter, organic compounds that can be used as hole transport substances are specifically listed.

[0101] For example, as aromatic amine compounds, N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), DNTPD, 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), etc. can be mentioned.

[0102] Also, as carbazole derivatives, specifically, 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), etc. can be mentioned. In addition, 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.

[0103] Examples of the aromatic hydrocarbon include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. Thus, it is more preferable to use an aromatic hydrocarbon having a hole mobility of 1×10 -6 cm 2 / Vs or more and having 14 to 42 carbon atoms. The aromatic hydrocarbon may have a vinyl skeleton. Examples of the aromatic hydrocarbon having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), etc.

[0104] Furthermore, polymer compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N’-[4-(4-diphenylamino)phenyl]phenyl-N’-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N’-bis(4-butylphenyl)-N,N’-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used.

[0105] In addition, as acceptor substances used for the hole injection layer 111 and the hole transport layer 112, compounds having an electron-withdrawing group (halogen group or cyano group) such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F 4 -TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN), etc. can be mentioned. In particular, a compound in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms like HAT-CN is thermally stable and preferable. Also, metal oxides belonging to Groups 4 to 8 in the periodic table of elements can be mentioned. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because they have high electron-accepting properties. Among them, molybdenum oxide is particularly preferable because it is stable even in the atmosphere, has low hygroscopicity, and is easy to handle.

[0106] The light-emitting layer 113 is a layer containing a light-emitting substance. Examples of the light-emitting substance include a fluorescent light-emitting substance and a phosphorescent light-emitting substance. In the light-emitting device which is one aspect of the present invention, it is preferable to use the organometallic complex shown in Embodiment 1 as the light-emitting substance in the light-emitting layer 113. Further, the light-emitting layer 113 preferably contains a substance having a larger triplet excitation energy than this organometallic complex (guest material) as a host material. Further, in addition to the light-emitting substance, the light-emitting layer 113 may be configured to contain two types of organic compounds (which may be any of the above host materials) that can form an exciplex (also referred to as an exciplex) when carriers (electrons and holes) in the light-emitting layer 113 recombine. In order to efficiently form an exciplex, it is particularly preferable to combine a compound that easily receives electrons (a material having electron-transporting properties) and a compound that easily receives holes (a material having hole-transporting properties). When a host material that forms an exciplex by combining a material having electron-transporting properties and a material having hole-transporting properties is used, it becomes easy to optimize the carrier balance between holes and electrons in the light-emitting layer by adjusting the mixing ratio of the material having electron-transporting properties and the material having hole-transporting properties. By optimizing the carrier balance between holes and electrons in the light-emitting layer, it is possible to suppress the deviation of the region where recombination of electrons and holes occurs in the light-emitting layer. By suppressing the deviation of the recombination region, the reliability of the light-emitting device can be improved.

[0107] In addition, as the compound that easily receives electrons (a material having electron-transporting properties) preferably used for forming the above exciplex, a π-electron deficient heteroaromatic such as a nitrogen-containing heteroaromatic compound or a metal complex can be used. Specifically, bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2) Metal complexes such as bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and heterocyclic compounds having a polyazole skeleton such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2’,2’’-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3’-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3’-(9H-carbazol-9-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,Heterocyclic compounds having a diazine skeleton such as 6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), heterocyclic compounds having a triazine skeleton such as 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), and heterocyclic compounds having a pyridine skeleton such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB) can be mentioned. Among the above, heterocyclic compounds having a diazine skeleton and a triazine skeleton and heterocyclic compounds having a pyridine skeleton are preferable because they have good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton and a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage.,

[0108] In addition, as a compound (material having hole transporting property) that is preferably used for forming the above-mentioned exciplex and is easily receptive to holes, π-electron-excessive heteroaromatics (e.g., carbazole derivatives and indole derivatives) or aromatic amines can be preferably used. Specifically, 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPA2SF), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), NPB, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), BSPB, 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,(9-Dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), PCzPCA1, 3-[N-(4-Diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-Bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), DNTPD, 3,6-Bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), PCzPCA2, 4-Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-Diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-Naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-Di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 3-[N-(1-Naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 9,9-Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-Phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-amine (abbreviation: PCBASF), N-(4-Biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(1,1'-Biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) and other compounds having an aromatic amine skeleton, 1,3-Bis(N-carbazolyl)benzene (abbreviation: mCP), CBP, 3,6-Bis(3,Compounds having a carbazole skeleton such as 5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 9-phenyl-9H-3-(9-phenyl-9H-carbazol-3-yl)carbazole (abbreviation: PCCP), and compounds having a thiophene skeleton such as 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton such as 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) can be mentioned. Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage.,

[0109] In addition, in the light-emitting layer 113, by forming it including the above-described organometallic complex (guest material) and host material, highly efficient phosphorescent light emission can be obtained from the light-emitting layer 113.

[0110] In addition, the light-emitting layer 113 is not limited to the single-layer structure shown in FIG. 1A in the light-emitting device, and may have a stacked structure of two or more layers as shown in FIG. 1B. However, in this case, it is assumed that light emission can be obtained from each of the stacked layers. For example, the first light-emitting layer 113(a1) may be configured to emit fluorescence, and the second light-emitting layer 113(a2) stacked on the first light-emitting layer 113(a1) may be configured to emit phosphorescence. Note that the stacking order may be reversed. In addition, in the layer where phosphorescence is obtained, it is preferable that light emission is obtained by energy transfer from an exciplex to a dopant. Regarding the emission color, the emission color obtained from one layer and the emission color obtained from the other layer may be the same or different. When they are different, for example, the configuration may be such that blue light emission is obtained from one layer and orange light emission or yellow light emission is obtained from the other layer. In addition, each layer may be configured to contain a plurality of types of dopants.

[0111] Note that when the light-emitting layer 113 has a stacked structure, in addition to the organometallic complex shown in Embodiment 1, a light-emitting substance that converts singlet excitation energy into light emission, a light-emitting substance that converts triplet excitation energy into light emission, or the like can be used alone or in combination. In this case, for example, the following can be mentioned.

[0112] Examples of the light-emitting substance that converts singlet excitation energy into light emission include substances that emit fluorescence (fluorescent compounds).

[0113] Examples of the fluorescent substances include N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyl-di-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N''' -octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-Biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), Rubrene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), {2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), {2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), etc. can be mentioned.,

[0114] Examples of luminescent materials that convert triplet excitation energy into luminescence include, for example, substances that emit phosphorescence (phosphorescent compounds) and TADF materials (thermally activated delayed fluorescence compounds) that exhibit thermally activated delayed fluorescence (TADF). Note that the delayed fluorescence in TADF materials refers to luminescence that has a spectrum similar to that of normal fluorescence but has a significantly longer lifetime. The lifetime is 1×10 -6 seconds or more, preferably 1×10 -3 seconds or more.

[0115] Examples of substances that emit phosphorescence include bis{2-[3’,5’-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}iridium(III) picolinate (abbreviation: [Ir(CF 3 ppy) 2 (pic)]), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’ iridium(III) acetylacetonate (abbreviation: FIracac), tris(2-phenylpyridinato)iridium(III) (abbreviation: [Ir(ppy) 3 ), bis(2-phenylpyridinato)iridium(III) acetylacetonate (abbreviation: [Ir(ppy) 2 (acac)]), tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) 3 (Phen)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq) 2 (acac)]), bis(2,4-diphenyl-1,3-oxazolato-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(dpo) 2 (acac)]), bis{2-[4’-(perfluorophenyl)phenyl]pyridinato-N,C 2’}iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph) 2 (acac)]), bis(2-phenylbenzothiazolato-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(bt) 2(acac)]), bis[2-(2'-benzo[4,5-a]thienyl)pyridinato-N,C 3’ ) iridium(III) acetylacetonate (abbreviation: [Ir(btp) 2 (acac)]), bis(1-phenylisoquinolinato-N,C 2’ ) iridium(III) acetylacetonate (abbreviation: [Ir(piq) 2 (acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) 2 (acac)]), (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me) 2 (acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr) 2 (acac)]), (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr) 2 (acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr) 2 (dpm)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) 2 (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) 2 (acac)]), 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP), tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM) 3 (Phen)]), tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA) 3(Phen), etc. can be mentioned.

[0116] In addition, examples of TADF materials include fullerenes and their derivatives, acridine derivatives such as proflavine, eosin, etc. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), etc. can be mentioned. Examples of the metal-containing porphyrins include protoporphyrin-tin fluoride complex (abbreviation: SnF 2 (Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF 2 (Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF 2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF 2 (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF 2 (OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF 2 (Etio I)), octaethylporphyrin-platinum chloride complex (abbreviation: PtCl 2 OEP), etc. can be mentioned. Furthermore, heterocyclic compounds having a π-electron-excessive heteroaromatic ring and a π-electron-deficient heteroaromatic ring such as 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ) can also be used. Note that a substance in which a π-electron-excessive heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferable because both the donor property of the π-electron-excessive heteroaromatic ring and the acceptor property of the π-electron-deficient heteroaromatic ring become strong, and the energy difference between S1 and T1 becomes small.

[0117] Furthermore, quantum dots (QD) with unique optical properties can also be used in the light-emitting layer 113. Note that QD refers to nanoscale semiconductor crystals, specifically having a diameter of approximately several nm to several tens of nm. Also, since the optical and electronic properties can be changed by varying the crystal size, it is easy to adjust the emission color, etc. In addition, because the peak width of the emission spectrum of quantum dots is narrow, light emission with good color purity can be obtained.

[0118] Examples of materials constituting quantum dots include Group 14 elements, Group 15 elements, Group 16 elements of the periodic table, compounds composed of a plurality of Group 14 elements, compounds of elements belonging to Groups 4 to 14 and Group 16 elements, compounds of Group 2 elements and Group 16 elements, compounds of Group 13 elements and Group 15 elements, compounds of Group 13 elements and Group 17 elements, compounds of Group 14 elements and Group 15 elements, compounds of Group 11 elements and Group 17 elements, iron oxides, titanium oxides, chalcogenide spinels, various semiconductor clusters, and the like.

[0119] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, indium arsenide, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium antimonide, aluminum phosphide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, indium selenide, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, calcium selenide, calcium telluride, beryllium sulfide, beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide, tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron trioxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide, silicon nitride, germanium nitride, aluminum oxide, barium titanate, a compound of selenium, zinc and cadmium, a compound of indium, arsenic and phosphorus, a compound of cadmium, selenium and sulfur, a compound of cadmium, selenium and tellurium, a compound of indium, gallium and arsenic, a compound of indium, gallium and selenium, a compound of indium, selenium and sulfur, a compound of copper, indium and sulfur, and combinations thereof, etc. can be mentioned. However, it is not limited thereto. Also, so-called alloy-type quantum dots whose composition is represented by an arbitrary ratio may be used. For example, alloy-type quantum dots of cadmium, selenium and sulfur can change the emission wavelength by changing the content ratio of the elements, so it is one of the effective means to obtain blue light emission.

[0120] In addition, as the structure of the quantum dots, there are core type, core-shell type, core-multi-shell type, etc., and any of them may be used. In the case of core-shell type or core-multi-shell type quantum dots where a shell is formed covering the core, by forming the shell using another inorganic material having a wider bandgap than the inorganic material used for the core, the influence of defects and dangling bonds present on the nanocrystal surface can be reduced, and the quantum efficiency of light emission can be greatly improved, which is preferable.

[0121] In addition, since QD can be dispersed in a solution, the light-emitting layer 113 can be formed by a coating method, an inkjet method, a printing method, etc. Since QD not only has bright and vivid color development, can emit light of a wide range of wavelengths, and is highly efficient and long-lived, the device characteristics can be improved by using it for the light-emitting layer 113.

[0122] The electron transport layer 114 is a layer containing a substance with high electron transport properties (also referred to as an electron transport compound). Tris(8-quinolinolato)aluminum (abbreviation: Alq 3 ), Tris(4-methyl-8-quinolinolato)aluminum (abbreviation: Almq 3 ), BeBq 2 , BAlq, Bis[2-(2-hydroxyphenyl)benzoxazolato]zinc (abbreviation: Zn(BOX) 2 ), Bis[2-(2-hydroxyphenyl)benzothiazolato]zinc (abbreviation: Zn(BTZ) 2Metal complexes such as can be used. Also, heteroaromatic compounds such as PBD, 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), TAZ, 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs) can also be used. Further, in addition to poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy), a polymer compound having a phosphine oxide skeleton and the like can also be used. The substances described here mainly have an electron mobility of 1×10 -6 cm 2 / Vs or more. Note that as long as the substance has higher electron transportability than holes, substances other than the above may be used as the electron transport layer 114.

[0123] Also, the electron transport layer 114 may have not only a single-layer structure but also a structure in which two or more layers made of the above substances are laminated.

[0124] The electron injection layer 115 is a layer containing a substance with high electron injection properties. For the electron injection layer 115, alkali metals, alkaline earth metals, or their compounds such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF 2 ), lithium oxide (LiOx), etc. can be used. Also, erbium fluoride (ErF 3It is possible to use a rare earth metal compound such as (0)). Further, an electride may be used for the electron injection layer 115. Examples of the electride include a substance obtained by adding electrons at a high concentration to a mixed oxide of calcium and aluminum. In addition, the substance constituting the above-described electron transport layer 114 can also be used.

[0125] Further, a composite material formed by mixing an organic compound and an electron donor may be used for the electron injection layer 115. Since electrons are generated in the organic compound by the electron donor in such a composite material, it has excellent electron injection properties and electron transport properties. In this case, the organic compound is preferably a material excellent in transporting the generated electrons. Specifically, for example, the substance (metal complex, heteroaromatic compound, etc.) constituting the above-described electron transport layer 114 can be used. Any substance that exhibits electron-donating properties with respect to the organic compound may be used as the electron donor. Specifically, an alkali metal, an alkaline earth metal, or a rare earth metal is preferable, and examples include lithium, cesium, magnesium, calcium, erbium, ytterbium, etc. In addition, an alkali metal oxide or an alkaline earth metal oxide is preferable, and examples include lithium oxide, calcium oxide, barium oxide, etc. Further, a Lewis base such as magnesium oxide can also be used. Further, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can also be used.

[0126] Note that the above-described hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115 can be formed by using a method such as a vapor deposition method (including a vacuum vapor deposition method), a printing method (for example, a relief printing method, an intaglio printing method, a gravure printing method, a lithographic printing method, a screen printing method, etc.), an inkjet method, a coating method, etc. alone or in combination. In addition to the above-described materials, inorganic compounds such as quantum dots or polymer compounds (oligomers, dendrimers, polymers, etc.) may be used for the above-described hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115.

[0127] In the above-described light-emitting device, a current flows due to the potential difference applied between the first electrode 101 and the second electrode 103, and light is emitted by the recombination of holes and electrons in the EL layer 102. Then, this light emission is taken out to the outside through either one or both of the first electrode 101 and the second electrode 103. Therefore, either one or both of the first electrode 101 and the second electrode 103 are electrodes having translucency.

[0128] Since the light-emitting device described above can obtain phosphorescent light emission based on an organometallic complex, a highly efficient light-emitting device can be realized as compared with a light-emitting device using only a fluorescent compound.

[0129] It should be noted that the configuration shown in this embodiment can be used in appropriate combination with the configuration shown in other embodiments.

[0130] (Embodiment 3) In this embodiment, a light-emitting device having an EL layer that can use an organometallic complex produced by a production method which is one aspect of the present invention, and having a structure with a plurality of EL layers (hereinafter referred to as a tandem type light-emitting device) will be described.

[0131] The light-emitting device shown in this embodiment is a tandem type light-emitting device having a plurality of EL layers (first EL layer 202(1), second EL layer 202(2)) between a pair of electrodes (first electrode 201 and second electrode 204) via a charge generation layer 205 as shown in Fig. 2A.

[0132] In this embodiment, the first electrode 201 is an electrode that functions as an anode, and the second electrode 204 is an electrode that functions as a cathode. Note that the first electrode 201 and the second electrode 204 can use the same configuration as in Embodiment 2. Also, the plurality of EL layers (the first EL layer 202(1), the second EL layer 202(2)) may have the same configuration as the EL layer shown in Embodiment 2, or either one of them may have the same configuration. That is, the first EL layer 202(1) and the second EL layer 202(2) may have the same configuration or different configurations. In the case of the same configuration, Embodiment 2 can be applied.

[0133] Also, the charge generation layer 205 provided between the plurality of EL layers (the first EL layer 202(1), the second EL layer 202(2)) has a function of injecting electrons into one EL layer and holes into the other EL layer when a voltage is applied between the first electrode 201 and the second electrode 204. In the case of this embodiment, when a voltage is applied so that the potential of the first electrode 201 is higher than that of the second electrode 204, electrons are injected from the charge generation layer 205 into the first EL layer 202(1), and holes are injected into the second EL layer 202(2).

[0134] Note that the charge generation layer 205 preferably has translucency with respect to visible light (specifically, the transmittance of visible light of the charge generation layer 205 is 40% or more) from the viewpoint of light extraction efficiency. Also, the charge generation layer 205 can function even with a lower conductivity than the first electrode 201 or the second electrode 204.

[0135] The charge generation layer 205 may have a configuration in which an electron acceptor is added to an organic compound with high hole transportability, or a configuration in which an electron donor is added to an organic compound with high electron transportability. Also, both of these configurations may be laminated.

[0136] When the structure is such that an electron acceptor is added to an organic compound with high hole transport properties, as the organic compound with high hole transport properties, the substances shown as the substances with high hole transport properties used for the hole injection layer 111 and the hole transport layer 112 in Embodiment 2 can be used. For example, aromatic amine compounds such as NPB, TPD, TDATA, MTDATA, and BSPB can be used. The substances described here mainly have a hole mobility of 1×10 -6 cm 2 / Vs or more. However, as long as it is an organic compound with higher hole transport properties than electrons, substances other than the above can also be used.

[0137] In addition, examples of the electron acceptor include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F 4 -TCNQ), chloranil, etc. Metal oxides belonging to Groups 4 to 8 in the periodic table of elements can also be mentioned. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because they have high electron accepting properties. Among them, molybdenum oxide is particularly preferable because it is stable in the air, has low hygroscopicity, and is easy to handle.

[0138] On the other hand, when the structure is such that an electron donor is added to an organic compound with high electron transport properties, as the organic compound with high electron transport properties, the substances shown as the substances with high electron transport properties used for the electron transport layer 114 in Embodiment 2 can be used. For example, metal complexes having a quinoline skeleton or a benzoquinoline skeleton such as Alq, Almq 3 、BeBq 2 、BAlq, etc. can be used. In addition, metal complexes having oxazole-based or thiazole-based ligands such as Zn(BOX) 2 、Zn(BTZ) 2 can also be used. Furthermore, in addition to metal complexes, PBD, OXD-7, TAZ, BPhen, BCP, etc. can also be used. The substances described here mainly have an electron mobility of 1×10 -6 cm 2It is a substance having an electron mobility of 1 / Vs or more. In addition, as long as it is an organic compound with higher electron transportability than holes, substances other than the above may be used.

[0139] In addition, as the electron donor, an alkali metal, an alkaline earth metal, a rare earth metal, a metal belonging to Groups 2 and 13 in the periodic table, and their oxides and carbonates can be used. Specifically, it is preferable to use lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, etc. Also, an organic compound such as tetrathianaphthacene may be used as the electron donor.

[0140] Note that by forming the charge generation layer 205 using the above-described materials, an increase in the driving voltage when the EL layer is laminated can be suppressed. Further, as a method for forming the charge generation layer 205, methods such as a vapor deposition method (including a vacuum vapor deposition method), a printing method (for example, a relief printing method, an intaglio printing method, a gravure printing method, a lithographic printing method, a screen printing method, etc.), an inkjet method, and a coating method can be used alone or in combination.

[0141] In this embodiment, a light-emitting device having two EL layers has been described. However, as shown in FIG. 2B, the same applies to a light-emitting device in which n EL layers (202(1) to 202(n), where n is 3 or more) are laminated. When there are a plurality of EL layers between a pair of electrodes as in the light-emitting device according to this embodiment, by disposing charge generation layers (205(1) to 205(n - 1)) between the EL layers, light emission in a high-luminance region is possible while keeping the current density low. Since the current density can be kept low, a long-life element can be realized.

[0142] Also, by making the emission colors of the respective EL layers different, it is possible to obtain emission of a desired color for the entire light-emitting device. For example, in a light-emitting device having two EL layers, by making the emission color of the first EL layer and the emission color of the second EL layer be in a complementary color relationship, it is also possible to obtain a light-emitting device that emits white light as a whole. Note that complementary colors refer to the relationship between colors that become achromatic when mixed. That is, when lights of colors in a complementary color relationship are mixed with each other, white light can be obtained. Specifically, an example is a combination in which blue emission is obtained from the first EL layer and yellow emission or orange emission is obtained from the second EL layer. In this case, it is not necessary for both the blue emission and the yellow emission (or orange emission) to be the same fluorescence emission or phosphorescence emission. A combination in which the blue emission is fluorescence emission and the yellow emission (or orange emission) is phosphorescence emission, or the reverse combination may also be used.

[0143] The same applies to a light-emitting device having three EL layers. For example, when the emission color of the first EL layer is red, the emission color of the second EL layer is green, and the emission color of the third EL layer is blue, white light can be obtained for the entire light-emitting device.

[0144] Note that the configuration shown in this embodiment can be used in appropriate combination with the configuration shown in other embodiments.

Example

[0145] ≪Synthesis Example 1≫ In this example, a method for synthesizing an organometallic complex represented by the structural formula (100) of Embodiment 1, bis{4,6-dimethyl-2-[5-(5-cyano-2-methylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O’)iridium(III) (abbreviation: [Ir(dmdppr-m5CP) 2 (dpm)]) will be described. Note that the structure of [Ir(dmdppr-m5CP) 2 (dpm)] is shown below.

[0146]

Chem.

[0147] <Step 1: Synthesis of 5-(5-Cyano-2-methylphenyl)-2,3-bis(3,5-dimethylphenyl)pyrazine (abbreviation: Hdmdppr-m5CP)> First, 1.83 g of 5,6-bis(3,5-dimethylphenyl)pyrazin-2-yl trifluoromethanesulfonate, 0.79 g of 5-cyano-2-methylphenylboronic acid, 3.17 g of tripotassium phosphate, 33 mL of toluene, and 3.3 mL of water were placed in a three-necked flask, and the inside was purged with nitrogen. After degassing by stirring under reduced pressure in the flask, 0.038 g of tris(dibenzylideneacetone)dipalladium(0) and 0.075 g of tris(2,6-dimethoxyphenyl)phosphine were added, and the mixture was refluxed for 8 hours. After the reaction, extraction with toluene was performed. Then, purification was carried out by flash column chromatography using hexane:ethyl acetate = 5:1 as the developing solvent to obtain the target pyrazine derivative, Hdmdppr-m5CP (abbreviation) (white solid, yield 96%). The synthesis scheme of Step 1 is shown in the following (a-1).

[0148]

Chem.

[0149] <Step 2: Synthesis of Di-μ-chloro-tetrakis{4,6-dimethyl-2-[5-(5-cyano-2-methylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}diiridium(III) (abbreviation: [Ir(dmdppr-m5CP) 2 Cl] 2 ) Next, 15 mL of 2-ethoxyethanol, 5 mL of water, 1.59 g of Hdmdppr-m5CP (abbreviation) obtained in Step 1 above, iridium chloride hydrate (IrCl 3 ·H 20.57 g of O) (manufactured by Furuya Metal Co., Ltd.) was placed in an eggplant-shaped flask equipped with a reflux tube, and the inside of the flask was purged with argon. Then, it was irradiated with microwaves (2.45 GHz, 100 W) for 1 hour to cause a reaction. After distilling off the solvent, the obtained residue was suction filtered and washed with methanol to obtain a dinuclear complex, [Ir(dmdppr-m5CP) 2 Cl] 2 (reddish-brown solid, yield 66%). The synthesis scheme of Step 2 is shown in (a-2) below.

[0150]

Chemical formula

[0151] <Step 3: Synthesis of bis{4,6-dimethyl-2-[5-(5-cyano-2-methylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O’)iridium(III) (abbreviation: [Ir(dmdppr-m5CP) 2 (dpm)]> Next, 1.00 g of the dinuclear complex, [Ir(dmdppr-m5CP) 2 Cl] 2 , 0.38 g of dipivaloylmethane (abbreviation: Hdpm), and 0.51 g of sodium carbonate were placed in a three-necked flask equipped with a reflux tube, and the inside of the flask was purged with nitrogen. Then, 12 mL of (anhydrous) N,N-dimethylformamide (abbreviation: DMF) was added, and the mixture was stirred at 153 °C for 2 hours to cause a reaction.

[0152] After a predetermined time had elapsed, the obtained mixture was suction filtered with toluene, and the filtrate was concentrated. The obtained residue was purified by silica gel column chromatography using dichloromethane as the developing solvent, and then recrystallized from a mixed solvent of dichloromethane and methanol to obtain an organometallic complex, [Ir(dmdppr-m5CP) 2 (dpm)] as a dark red solid (yield, 0.68 g, yield 59%).

[0153] The obtained 0.68 g of dark red solid was purified by sublimation using the train sublimation method. The sublimation purification conditions were as follows: while flowing argon gas at a flow rate of 10.5 mL / min under a pressure of 2.6 Pa, the solid was heated at 300 °C. After sublimation purification, 0.56 g of the target dark red solid was obtained with a yield of 82%. The synthesis scheme of Step 3 is shown in (a-3) below.

[0154] [Chemical formula]

[0155] In addition, the analysis results of the dark red solid obtained in Step 3 by nuclear magnetic resonance spectroscopy ( 1 1H-NMR) are shown below. Also, 1 the 1H-NMR chart is shown in Figure 3. From this, in this example, it was found that the organometallic complex represented by the above structural formula (100), [Ir(dmdppr-m5CP) 2 (dpm)] was obtained.

[0156] 1 1H-NMR. δ(CD 2 Cl 2 ): 0.95 (s, 18H), 1.42 (s, 6H), 1.95 (s, 6H), 2.38 (s, 12H), 2.49 (s, 6H), 5.68 (s, 1H), 6.48 (s, 2H), 6.83 (s, 2H), 7.20 (s, 2H), 7.35 (s, 4H), 7.43 (d, 2H), 7.62 (d, 2H), 7.70 (s, 2H), 8.43 (s, 2H).

[0157] Also, in this example, the same reaction was carried out using another reaction solvent instead of the reaction solvent used in Step 3 shown in the above synthesis scheme (a-3), N,N-dimethylformamide (abbreviation: DMF), to synthesize the organometallic complex, [Ir(dmdppr-m5CP) 2 (dpm)]. Table 1 below shows the heating temperature (°C) and heating time (hours) during the reaction for each solvent, and [Ir(dmdppr-m5CP) 2(dpm)] yields (%) are shown in Table 1 below. The heating temperature of each solvent in Table 1 corresponds to the boiling point of each solvent.

[0158] [Table 1]

[0159] From the results shown in Table 1, in the relationship between the heating temperature (°C) and the yield (%) shown in Figure 4, among the solvents capable of heating at 80°C or higher, excluding alcohols which are protic solvents, it was found that a yield of 24% or more can be obtained when using aprotic solvents such as amide compounds, ethers, and nitriles. Among them, when an amide compound with a high heating temperature of 150°C or higher is used as the reaction solvent, the yield of the organometallic complex, [Ir(dmdppr-m5CP) 2 (dpm)] was found to be as high as 40% or more.

[0160] Note that aprotic solvents prevent the generation of protons more than protic solvents. For example, they can suppress side reactions such as the reaction of protons as electrophiles with the highly electron-dense cyano group contained in the organometallic complex, resulting in the elimination of the cyano group. Therefore, it is preferable to use an aprotic solvent as the reaction solvent in the above reaction.

[0161] Also, when the heating temperature is high, the main reaction proceeds faster than the side reaction, and the side reaction is suppressed. Therefore, among the above-mentioned aprotic solvents, those with particularly high boiling points are preferred, preferably aprotic solvents with a boiling point of 80°C or higher, and more preferably aprotic solvents with a boiling point of 150°C or higher.

[0162] Therefore, as shown in this example, by reacting a multinuclear complex containing a cyano group cross-linked with chlorine with β-diketone in the presence of an aprotic solvent and a base such as an amide compound, an ether, and a nitrile, which have a boiling point of 80°C or higher, it is possible to improve the yield of the produced organometallic complex.

Explanation of Symbols

[0163] 101: First electrode, 102: EL layer, 103: Second electrode, 111: Hole injection layer, 112: Hole transport layer, 113: Light-emitting layer, 114: Electron transport layer, 115: Electron injection layer, 201: First electrode, 202(1): First EL layer, 202(2): Second EL layer, 202(n - 1): (n - 1)th EL layer, 202(n): nth EL layer, 204: Second electrode, 205: Charge generation layer, 205(1): First charge generation layer, 205(2): Second charge generation layer, 205(n - 2): (n - 2)th charge generation layer, 205(n - 1): (n - 1)th charge generation layer

Claims

A method for producing an organometallic complex, which comprises reacting a polynuclear complex containing a cyano group represented by the general formula (Gp) with a β-diketone represented by the general formula (L1) in the presence of an amide compound having a boiling point of 80 °C or higher and a base. (In the general formula (Gp), A1 to A4 each independently represent a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R1 to R6 each independently represent hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R7 to R11 each independently represent hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, or a cyano group, and at least one represents a cyano group. In the general formula (L1), R20 to R22 each independently represent hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms.) 【Chemical 1】 A method for producing an organometallic complex according to claim 1, wherein the amide compound has a boiling point of 150 °C or higher. A method for producing an organometallic complex, which comprises reacting a polynuclear complex containing a cyano group represented by the general formula (Gp) with a β-diketone represented by the general formula (L1) in the presence of an aprotic solvent having a boiling point of 80 °C or higher and a base. ​ ​ ​ 【Chemical Formula 2】 (In the general formula (Gp), A1 to A4 each independently represent a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R1 to R6 each independently represent hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Further, R7 to R11 each independently represent hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms, or a cyano group, and at least one represents a cyano group. Also, in the general formula (L1), R20 to R22 each independently represent hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms.)

4. In claim 3, A method for producing an organometallic complex, wherein the boiling point of the aprotic solvent is 150 °C or higher.

5. In claim 3 or claim 4, A method for producing an organometallic complex, wherein the aprotic solvent is either an ether-based solvent or a nitrile-based solvent.

6. In claim 3 or claim 4, A method for producing an organometallic complex, wherein the aprotic solvent is any one of N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,2-dimethoxyethane, 1,4-dioxane, anisole, diethylene glycol dimethyl ether, acetonitrile, and propionitrile.

7. In any one of claims 1 to 6, A method for producing an organometallic complex, wherein the polynuclear complex containing a cyano group represented by the general formula (Gp) is a polynuclear complex represented by the following formula (a-2). 【Chemical 3】

8. In any one of claims 1 to 7, A method for producing an organometallic complex, wherein the β-diketone represented by the general formula (L1) is dipivaloylmethane.

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