Heterocyclic compound and organic electroluminescent element, electronic device

Abstract

The present application aims at providing a compound having a high refractive index in the range of wavelengths of 450 nm to 750 nm in a capping layer, in order to improve the light extraction efficiency of an organic EL element. The present application is directed to a heterocyclic compound having excellent stability and durability of a thin film, capable of increasing the refractive index by adjusting the molecular structure, and designed as a material constituting a capping layer, thereby obtaining an organic EL element having excellent luminous efficiency.

Description

Technical Field

[0001] The present invention relates to heterocyclic compounds suitable for self-emissive electronic components, particularly organic electroluminescent elements (hereinafter referred to as organic EL elements), or electronic devices suitable for various display devices, and organic EL elements or electronic devices using the heterocyclic compounds. Background Technology

[0002] In 1987, CWTang et al. of Eastman Kodak developed a layered structure element that distributed various functions among different materials, thus making organic EL elements using organic materials practical devices. They achieved luminescence by layering an electron-transferring phosphor and a hole-transferring organic material, injecting the charges of both into the phosphor layer, thereby obtaining 1000 cd / m² at voltages below 10V. 2 The above high brightness (see Patent Document 1 and Patent Document 2).

[0003] To date, numerous improvements have been made to make organic EL devices practical, and the various functions of the stacked structure have been further subdivided. Among the electroluminescent devices that have an anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer and cathode arranged sequentially on the substrate, the light-emitting device with a bottom-emitting structure that emits light from the bottom has achieved high efficiency and durability (see, for example, non-patent literature 1).

[0004] In recent years, metals with high work functions have been used as anodes, and top-emitting light-emitting elements with upward-emitting structures have been increasingly adopted. In bottom-emitting structures where light is extracted from the bottom (where pixel circuitry is located), the area of ​​the light-emitting portion is limited. However, in top-emitting light-emitting elements, light is extracted from the top, thus avoiding obstruction of the pixel circuitry and providing the advantage of a wider light-emitting area. In top-emitting light-emitting elements, semi-transparent electrodes such as LiF / Al / Ag (see, for example, Non-Patent Document 2), Ca / Mg (see, for example, Non-Patent Document 3), and LiF / MgAg are used as cathodes.

[0005] In such light-emitting elements, if light emitted from the light-emitting layer is incident on other films at an angle greater than a certain angle, total internal reflection occurs at the interface between the light-emitting layer and other films. Therefore, only a portion of the emitted light can be utilized. In recent years, to improve light extraction efficiency, light-emitting elements with a high-refractive-index "capping layer" disposed on the outside of a semi-transparent electrode with a low refractive index have been proposed (see, for example, Non-Patent Literature 2 and Non-Patent Literature 3).

[0006] The effect of the capping layer in the top-emitting structure of the light-emitting element: In the light-emitting element using Ir(ppy)3 as the light-emitting material, the current efficiency is 38 cd / A without the capping layer, while in the light-emitting element using ZnSe with a film thickness of 60 nm as the capping layer, it is 64 cd / A, confirming an efficiency improvement of approximately 1.7 times. Furthermore, it is shown that the maximum transmittance of the semi-transparent electrode and the capping layer does not necessarily coincide with the maximum efficiency, indicating that the maximum light extraction efficiency is determined by interference effects (see, for example, Non-Patent Literature 3).

[0007] Previously, high-precision metal masks were used for the formation of capping layers. However, under high-temperature conditions, these masks deform due to heat, leading to reduced alignment accuracy. Since ZnSe has a melting point exceeding 1100°C (see, for example, Non-Patent Document 3), even with high-precision metal masks, improper deposition at the correct positions could potentially affect the light-emitting element itself. Furthermore, even sputtering methods can impact the light-emitting element, making capping layers composed of inorganic materials unsuitable.

[0008] Furthermore, when using tris(8-hydroxyquinoline)aluminum (Alq3) as a capping layer to adjust the refractive index (for example, see Non-Patent Literature 2), Alq3 is known to be an organic EL material commonly used as a green light-emitting material or an electron transport material. It has weak absorption around 450 nm when used in blue light-emitting materials, and therefore, in the case of blue light-emitting elements, there are also problems of reduced color purity and reduced light extraction efficiency.

[0009] In order to improve the characteristics of organic EL devices and to significantly improve the light extraction efficiency, the material used as the capping layer is required to be a material with high refractive index, low extinction coefficient, and excellent film stability and durability.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 8-048656

[0013] Patent Document 2: Japanese Patent No. 3194657

[0014] Non-patent literature

[0015] Non-patent literature 1: Proceedings of the 9th Workshop of the Chinese Society of Applied Physics, pp. 55-61 (2001)

[0016] Non-patent literature 2: Appl. Phys. Let., 78, 544 (2001)

[0017] Non-patent literature 3: Appl. Phys. Let., 82, 466 (2003) Summary of the Invention

[0018] The problem that the invention aims to solve

[0019] The object of this invention is to provide a compound with a high refractive index that allows light to pass through the capping layer (organic thin film) of an organic EL element in the wavelength range of 450 nm to 750 nm and has no absorption near 450 nm. Furthermore, by using the above-mentioned compound, an organic EL element, or an electronic device or electronic component, that improves light extraction efficiency can be provided.

[0020] As physical properties of the compounds constituting the capping layer (organic thin film) suitable for the present invention, the following can be listed: (1) high refractive index; (2) vapor deposition capability; (3) stable thin film state; (4) high glass transition temperature. In addition, as physical properties of the elements suitable for the present invention, the following can be listed: (1) high light extraction efficiency; (2) reduction in colorless purity; (3) light transmission without time variation; (4) long lifespan.

[0021] Methods for solving problems

[0022] In order to achieve the above-mentioned objectives, the inventors focused on the excellent stability and durability of thin films made of heterocyclic compounds, and the ability to increase the refractive index by adjusting the molecular structure. They designed molecules, manufactured organic EL elements using heterocyclic compounds as the material constituting the capping layer, and conducted in-depth evaluation of the characteristics of the elements, resulting in the completion of this invention.

[0023] That is, according to the present invention, the following heterocyclic compounds and organic EL elements are provided.

[0024] 1) Heterocyclic compounds represented by the following general formula (1),

[0025] [Chemistry 1]

[0026]

[0027] (In the formula, X1 and X2 can be the same or different, representing nitrogen atoms or CH groups, up to...)

[0028] One less nitrogen atom; L1 and L2 can be the same or different, representing a single bond, a substituted or unsubstituted ring forming a divalent group of an aromatic hydrocarbon with 6-18 carbon atoms, or a substituted or unsubstituted ring forming a divalent group of an aromatic heterocycle with 5-18 atoms. Ar1 and Ar2 can be the same or different, representing a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group.

[0029] 2) The heterocyclic compound according to 1) above, wherein the heterocyclic compound is represented by the following general formula (1-a):

[0030] [Chemistry 2]

[0031]

[0032] (In the formula, L1, L2, Ar1, and Ar2 are defined as in the general formula (1).)

[0033] 3) The heterocyclic compound according to 1) above, wherein the heterocyclic compound is represented by the following general formula (1-b):

[0034] [Chemistry 3]

[0035]

[0036] (In the formula, L1, L2, Ar1, and Ar2 are defined as in the general formula (1).)

[0037] 4) The heterocyclic compound according to any one of 1) to 3) above, characterized in that, in the general formula (1), general formula (1-a), or general formula (1-b), at least one of L1 and L2 is a single bond, a divalent group generated by removing two hydrogen atoms from substituted or unsubstituted benzene, a divalent group generated by removing two hydrogen atoms from substituted or unsubstituted biphenyl, or a divalent group generated by removing two hydrogen atoms from substituted or unsubstituted naphthalene.

[0038] 5) A heterocyclic compound according to any one of 1) to 3) above, wherein, in general formula (1), general formula (1-a), or general formula (1-b), at least one of L1 and L2 is represented by the following general formula (2):

[0039] [Chemistry 4]

[0040]

[0041] (In the formula, R1 to R4 represent hydrogen atoms, cyano groups, substituted or unsubstituted alkyl groups with 1 to 6 carbon atoms, substituted or unsubstituted alkoxy groups with 1 to 6 carbon atoms, and substituted or unsubstituted aromatic hydrocarbon groups with 6 to 12 carbon atoms forming a ring.)

[0042] 6) An organic thin film comprising a heterocyclic compound according to any one of 1) to 5) above, characterized in that the refractive index is 1.70 or higher in the wavelength range of 450 nm to 750 nm.

[0043] 7) An organic EL element having at least an anode electrode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode electrode, and a capping layer in sequence, characterized in that the capping layer is an organic thin film according to 6) above.

[0044] 8) An electronic device or electronic component having a pair of electrodes and at least one organic layer sandwiched therebetween, characterized in that the organic layer uses a heterocyclic compound according to any one of 1) to 5) above as its constituent material.

[0045] In this invention, the "substituent" used for "substituted or unsubstituted" can specifically include cyano, nitro, halogen atoms; alkyl groups with 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, and n-hexyl; alkoxy groups with 1 to 6 carbon atoms, such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy, and n-hexyloxy; phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthrene, etc. Aromatic hydrocarbon groups such as fluorenyl, spirodifluorenyl, indyl, pyrene, peryl, fluoranyl, and benzo[9,10]phenanthrene; aromatic heterocyclic groups such as pyridyl, pyrimidinyl, triazinyl, furanyl, pyrrolithyl, thiopheneyl, quinolinyl, isoquinolinyl, benzofuranyl, benzothiopheneyl, indolyl, carbazoyl, quinoxalinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothiopheneyl, naphridinyl, phenanthrolinyl, acridineyl, carbazoyl, benzoxazolyl, benzothiazoyl, and phenoxazinyl, which may be further substituted by the "substituents" exemplified above.

[0046] In this invention, among the "substituents" exemplified above, cyano, nitro, halogen atom, alkyl with 1 to 3 carbon atoms, alkoxy with 1 to 3 carbon atoms, phenyl, naphthyl, and quinolinyl are preferably used.

[0047] As for "aromatic hydrocarbons" in the general formula (1), which are "a divalent group of an aromatic hydrocarbon with 6 to 18 carbon atoms consisting of substituted or unsubstituted rings", specific examples include benzene, biphenyl, terphenyl, naphthalene, anthracene, phenanthrene, fluorene, etc.

[0048] Furthermore, the "divalent group of an aromatic hydrocarbon" in the general formula (1), which is represented by L1 and L2, which are "a divalent group of an aromatic hydrocarbon with 6 to 18 carbon atoms consisting of substituted or unsubstituted rings", refers to the divalent group generated by removing 2 hydrogen atoms from the above-mentioned "aromatic hydrocarbon".

[0049] Here, as the aforementioned "divalent group of aromatic hydrocarbon", the preferred divalent group is the one generated by removing two hydrogen atoms from benzene (phenylene), the divalent group generated by removing two hydrogen atoms from biphenyl, and the divalent group generated by removing two hydrogen atoms from naphthalene. More preferably, the divalent group is the one generated by removing two hydrogen atoms from benzene (phenylene) and the divalent group is the one generated by removing two hydrogen atoms from naphthalene.

[0050] Furthermore, as a divalent group (phenylene) generated by removing two hydrogen atoms from benzene, it is preferable to generate a divalent group (1,4-phenylene) by removing two hydrogen atoms at the 1,4-position of benzene, or to generate a divalent group (1,3-phenylene) by removing two hydrogen atoms at the 1,3-position of benzene.

[0051] Furthermore, as a divalent group generated by removing two hydrogen atoms from biphenyl, it is preferable to generate a divalent group by removing two hydrogen atoms at the 4,4'-position of biphenyl.

[0052] Furthermore, as a divalent group generated by removing two hydrogen atoms from naphthalene, it is preferable to generate a divalent group by removing two hydrogen atoms at the 1,4-position of naphthalene.

[0053] As for the "aromatic heterocycles" represented by L1 and L2 in general formula (1), which are "divalent groups of aromatic heterocycles with 5 to 18 atoms consisting of substituted or unsubstituted rings", examples include pyridine, pyrimidine, furan, pyrrole, thiophene, quinoline, benzofuran, benzothiophene, dibenzofuran, dibenzothiophene, phenanthroline, etc.

[0054] Furthermore, the "divalent group of an aromatic heterocycle" in the general formula (1), represented by L1 and L2, which are "divalent groups of an aromatic heterocycle with 5 to 18 atoms consisting of substituted or unsubstituted rings", refers to the divalent group generated by removing two hydrogen atoms from the aforementioned "aromatic heterocycle".

[0055] As for the "substituted or unsubstituted aromatic hydrocarbon groups" represented by Ar1 and Ar2 in general formula (1), specifically, phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthryl, fluorenyl, spirodifluorenyl, indyl, pyrene, perylene, fluoranyl, benzo[9,10]phenanthryl, etc.

[0056] As for the "aromatic heterocyclic group" represented by Ar1 and Ar2 in general formula (1), specifically, pyridyl, pyrimidinyl, triazinyl, furanyl, pyrrolithyl, thiopheneyl, quinolinyl, isoquinolinyl, benzofuranyl, benzothiopheneyl, indolyl, carbazolyl, quinoxolinyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothiopheneyl, naphridinyl, phenanthrololinyl, acridineyl, carbazolyl, benzoxazolyl, benzothiazolyl, phenoxazinyl, etc.

[0057] As for "alkyl groups with 1 to 6 carbon atoms" represented by R1 to R4 in general formula (2), specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, etc. can be listed.

[0058] As for the "alkoxy group with 1 to 6 carbon atoms" represented by R1 to R4 in general formula (2), specifically, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy, n-hexoxy, etc.

[0059] Specifically, the "aromatic hydrocarbon group with 6 to 12 carbon atoms formed by substituted or unsubstituted rings" represented by R1 to R4 in general formula (2) can be exemplified by phenyl, biphenyl, naphthyl, etc.

[0060] As a heterocyclic compound represented by the above general formula (1) of the present invention, it is preferred to have a refractive index of 1.70 or more in the wavelength range of 450 nm to 750 nm, more preferably 1.80 or more, and even more preferably 1.85 or more.

[0061] As a heterocyclic compound represented by the above general formula (1) of the present invention, a heterocyclic compound represented by (1-a) or (1-b) is preferred.

[0062] In addition, in general formula (1), general formula (1-a), or general formula (1-b), it is preferred that at least one of L1 and L2 is a divalent group represented by general formula (2).

[0063] In general formula (2), it is preferred that R1 to R4 are hydrogen atoms, and more preferably all of R1 to R4 are hydrogen atoms.

[0064] In the organic EL element of the present invention, the thickness of the capping layer is preferably in the range of 30 nm to 120 nm, and more preferably in the range of 40 nm to 80 nm.

[0065] Furthermore, in the organic EL element of the present invention, the above-mentioned capping layer can be manufactured by laminating or forming a hybrid layer of two or more different constituent materials.

[0066] Furthermore, in the organic EL element of the present invention, the refractive index of the capping layer is preferably 1.70 or more, more preferably 1.80 or more, and even more preferably 1.85 or more, in the wavelength range of light transmitted through the capping layer.

[0067] The effects of the invention

[0068] By using the heterocyclic compound of the present invention as a capping layer with a higher refractive index than the transparent or semi-transparent electrode disposed on the outside of the transparent or semi-transparent electrode of the organic EL element, it is possible to obtain an organic EL element that can significantly improve the light extraction efficiency.

[0069] Furthermore, the heterocyclic compounds of the present invention can be used not only in organic EL devices, but also in electronic devices such as electrophotographic sensors, image sensors, photoelectric conversion elements, and solar cells. Attached Figure Description

[0070] Figure 1 A diagram showing the structural formulas of compounds (1-1) to (1-16) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0071] Figure 2 A diagram showing the structural formulas of compounds (1-17) to (1-34) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0072] Figure 3 A diagram showing the structural formulas of compounds (1-35) to (1-50) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0073] Figure 4 A diagram showing the structural formulas of compounds (1-51) to (1-68) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0074] Figure 5 A diagram showing the structural formulas of compounds (1-69) to (1-82) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0075] Figure 6 A diagram showing the structural formulas of compounds (1-83) to (1-96) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0076] Figure 7 A diagram showing the structural formulas of compounds (1-97) to (1-110) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0077] Figure 8 A diagram showing the structural formulas of compounds (1-111) to (1-124) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0078] Figure 9A diagram showing the structural formulas of compounds (1-125) to (1-138) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0079] Figure 10 A diagram showing the structural formulas of compounds (1-139) to (1-152) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0080] Figure 11 A diagram showing the structural formulas of compounds (1-153) to (1-155) that are heterocyclic compounds represented by the general formula (1) of the present invention.

[0081] Figure 12 The diagram illustrates the configuration of the organic EL elements in Examples 21-38 and Comparative Examples 1-2. Detailed Implementation

[0082] The heterocyclic compounds represented by the general formula (1) of the present invention are novel compounds that can be synthesized by methods known to them.

[0083] Specific examples of heterocyclic compounds represented by the general formula (1) of the present invention are shown in Figures 1 to 11 However, it is not limited to these compounds.

[0084] There are no particular limitations on the method for manufacturing the heterocyclic compound represented by the general formula (1) of the present invention. The compound can be purified by known methods used in the purification of organic compounds, such as purification by column chromatography, adsorption purification by silica gel, activated carbon, activated clay, etc., recrystallization by solvent, and crystallization, and finally purification by sublimation. The compound can be identified by NMR analysis, etc. As physical properties, it is preferable to measure the melting point, glass transition temperature (Tg), and refractive index.

[0085] Melting point and glass transition temperature (Tg) can be determined, for example, using powder and a high-sensitivity differential scanning calorimeter (manufactured by Bruker-AXS, DSC3100SA).

[0086] Regarding the refractive index, it is possible to fabricate an 80 nm thin film on a silicon substrate and measure it using a spectrophotometer (Filmetrics, F10-RT-UV).

[0087] As for the structure of the organic EL element of the present invention, for example, in the case of a top-emitting light-emitting element, structures can be listed as follows: a structure that sequentially includes an anode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, and a capping layer on a glass substrate; a structure that has a hole injection layer between the anode and the hole transport layer; a structure that has an electron blocking layer between the hole transport layer and the light-emitting layer; a structure that has a hole blocking layer between the light-emitting layer and the electron transport layer; and a structure that has an electron injection layer between the electron transport layer and the cathode. In these multilayer structures, several organic layers can be omitted or combined, for example, a structure that combines a hole injection layer and a hole transport layer; a structure that combines a hole transport layer and an electron blocking layer; a structure that combines a hole blocking layer and an electron transport layer; or a structure that combines an electron transport layer and an electron injection layer. In addition, it is also possible to have a structure that stacks two or more organic layers with the same function, or a structure that stacks two hole transport layers; a structure that stacks two light-emitting layers; a structure that stacks two electron transport layers; or a structure that stacks two capping layers.

[0088] The total thickness of all layers in the organic EL element is preferably around 200 nm to 750 nm, more preferably around 350 nm to 600 nm. Furthermore, the thickness of the capping layer is preferably 30 nm to 120 nm, more preferably 40 nm to 80 nm. In this case, good light extraction efficiency can be obtained. It should be noted that the thickness of the capping layer can be appropriately varied depending on the type of light-emitting material used in the light-emitting element and the thickness of each layer of the organic EL element other than the capping layer.

[0089] As the anode of the organic EL element of the present invention, electrode materials with high work functions such as ITO and gold are used.

[0090] As the hole injection layer of the organic EL element of the present invention, arylamine compounds having a structure in which two or more triphenylamine structures are linked by single bonds or divalent groups without heteroatoms are preferred. Examples include benzidine derivatives and other arylamine compounds having a structure in which two triphenylamine structures are linked by single bonds or divalent groups without heteroatoms, starburst-type triphenylamine derivatives, and various triphenylamine tetramers. Additionally, porphyrin compounds represented by copper phthalocyanine, acceptor heterocyclic compounds such as hexacyanoazabenzo[9,10]phenanthrene, and coating-type polymers can be used. These can be used individually as films, as monolayers mixed with other materials, or as stacked structures of individually formed layers, mixed layers, or individually formed layers and mixed layers. In addition to vapor deposition, known methods such as spin coating and inkjet printing can also be used to form thin films with these materials.

[0091] As the hole transport layer of the organic EL element of the present invention, benzidine derivatives such as N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD), N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine (NPD), and N,N,N',N'-tetra(biphenyl)benzidine, 1,1-bis[4-(di-4-tolylamino)phenyl]cyclohexane (TAPC), and especially arylamine compounds having a structure in which two triphenylamine structures are linked by single bonds or divalent groups without heteroatoms, such as N,N,N',N'-tetra(biphenyl)benzidine, are preferred. Furthermore, arylamine compounds having only one triphenylamine structure in the molecule, arylamine compounds having a structure in which three or more triphenylamine structures are linked by single bonds or divalent groups without heteroatoms, such as various triphenylamine trimers and tetramers, are also preferred. These materials can be formed into films individually, or used as monolayers mixed with other materials, or as stacked structures of individual layers, mixed layers, or individual and mixed layers. Furthermore, coating-type polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) / poly(styrene sulfonate) (PSS) can be used as hole injection / transport layers. For these materials, in addition to vapor deposition, known methods such as spin coating and inkjet printing can also be used for film formation.

[0092] Furthermore, in the hole injection layer or hole transport layer, it is preferable to further p-dopat the material commonly used in this layer with antimony hexachloride, axial alkene derivatives, etc. Additionally, polymeric compounds such as TPD, which have a benzidine derivative structure in part of their structure, can be used.

[0093] As the electron blocking layer of the organic EL element of the present invention, carbazole derivatives such as 4,4',4”-tris(N-carbazole)triphenylamine (TCTA), 9,9-bis[4-(carbazole-9-yl)phenyl]fluorene, 1,3-bis(carbazole-9-yl)benzene (mCP), and 2,2-bis(4-carbazole-9-yl)adamantane (Ad-Cz) can be used, as well as 9-[4-(carbazole-9-yl)phenyl]-9-[4-(triphenylsilyl)benzene] Compounds with electron-blocking properties, such as those with triphenylsilyl and triarylamine structures, such as [-9H-fluorene], can be used as individual films, monolayers mixed with other materials, or in stacked structures of individual layers, mixed layers, or mixed layers. In addition to vapor deposition, these materials can be formed into thin films using known methods such as spin coating and inkjet printing.

[0094] As the light-emitting layer of the organic EL element of the present invention, in addition to metal complexes of hydroxyquinoline derivatives, primarily Alq3, various metal complexes, anthracene derivatives, bis(styrene)benzene derivatives, pyrene derivatives, oxazole derivatives, poly(p-phenylene)ethyne derivatives, etc., can also be used. Furthermore, the light-emitting layer can be constructed using a host material and a dopant material. As the host material, anthracene derivatives are preferred. In addition to the aforementioned light-emitting materials, heterocyclic compounds with a partial structure having an indole ring as a fused ring, heterocyclic compounds with a partial structure having a carbazole ring as a fused ring, carbazole derivatives, thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, etc., can also be used. Furthermore, as dopant materials, quinacridone, coumarin, rubrene, perylene and their derivatives, benzopyran derivatives, rhodamine derivatives, aminostyrene derivatives, etc., can be used. They can be used as individual films, as monolayers mixed with other materials, or as stacked structures of individual film layers, mixed film layers, or individual film layers and mixed film layers.

[0095] In addition, phosphorescent materials can also be used as luminescent materials. Phosphorescent materials composed of metal complexes such as iridium and platinum can be used. Green phosphorescent materials such as Ir(ppy)3, blue phosphorescent materials such as Firpic and Fir6, and red phosphorescent materials such as Btp2Ir(acac) can be used. As the host material, carbazole derivatives such as 4,4'-bis(N-carbazolyl)biphenyl (CBP), TCTA, and mCP can be used as the host material for hole injection / transport. As the host material for electron transport, p-bis(triphenylsilyl)benzene (UGH2) and 2,2',2”-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (TPBI) can be used to manufacture high-performance organic EL devices.

[0096] Regarding the doping of phosphorescent luminescent materials into the host material, in order to avoid concentration quenching, it is preferable to dope by co-evaporation at a rate of 1 to 30% by weight relative to the overall luminescent layer.

[0097] In addition, materials that emit delayed fluorescence can also be used as luminescent materials. For these materials, in addition to vapor deposition, known methods such as spin coating and inkjet printing can also be used to form thin films.

[0098] As the hole-blocking layer for the organic EL element of the present invention, compounds with hole-blocking properties, such as phenanthroline derivatives like copper hydroxide (BCP), metal complexes of hydroxyquinoline derivatives like bis(2-methyl-8-quinoline)-4-phenylphenol aluminum(III) (BAlq), various rare earth complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, and benzo[a]azole derivatives, can be used. These materials can also serve as electron transport layer materials. They can be formed into films individually, or used as monolayers mixed with other materials, or as stacked structures of layers formed individually, layers mixed together, or layers formed individually and layers mixed together. In addition to vapor deposition, known methods such as spin coating and inkjet printing can also be used to form thin films with these materials.

[0099] As the electron transport layer of the organic EL element of the present invention, in addition to metal complexes of hydroxyquinoline derivatives, primarily Alq3 and BAlq, various metal complexes, triazole derivatives, triazine derivatives, pyrimidine derivatives, oxadiazole derivatives, pyridine derivatives, benzimidazole derivatives, benzoxazole derivatives, thiadiazole derivatives, anthracene derivatives, carbodiimide derivatives, quinoxaline derivatives, pyridinodole derivatives, phenanthroline derivatives, thiophene derivatives, etc., can be used. These can be formed individually, used as monolayers mixed with other materials, or as stacked structures of individually formed layers, mixed layers, or individually formed layers and mixed layers. Regarding these materials, in addition to vapor deposition, known methods such as spin coating and inkjet printing can also be used for thin film formation.

[0100] As the electron injection layer of the organic EL element of the present invention, alkali metal salts such as lithium fluoride and cesium fluoride, alkaline earth metal salts such as magnesium fluoride, metal complexes of hydroxyquinoline derivatives such as lithium hydroxyquinoline, metal oxides such as aluminum oxide, or metals such as ytterbium (Yb), samarium (Sm), calcium (Ca), strontium (Sr), and cesium (Cs) can be used. With the preferred selection of the electron transport layer and the cathode, these can be omitted.

[0101] Furthermore, in the electron injection layer or electron transport layer, it is possible to use products obtained by further n-doping metals such as cesium with materials commonly used in that layer.

[0102] As the cathode of the organic EL element of the present invention, electrode materials with low work function such as aluminum, magnesium-silver alloys, magnesium-calcium alloys, magnesium-indium alloys, aluminum-magnesium alloys, ITO, IZO, etc. are used as electrode materials.

[0103] As the capping layer for the organic EL element of the present invention, heterocyclic compounds represented by the above general formulas (1), (1-a), or (1-b) are preferably used. With regard to these materials, in addition to vapor deposition, known methods such as spin coating and inkjet printing can also be used to form thin films.

[0104] It should be noted that the above description refers to organic EL elements with a top-emitting structure, but the present invention is not limited thereto. The same principle applies to organic EL elements with a bottom-emitting structure, and organic EL elements with a dual-emitting structure that emits light from both the top and bottom. In these cases, the electrode located in the direction that directs light from the emitting element outward needs to be transparent or semi-transparent.

[0105] Example

[0106] The following describes the embodiments of the present invention in detail using examples. The present invention is not limited to the following examples as long as it does not depart from its spirit.

[0107] [Example 1]

[0108] <Synthesis of 2,5-bis{4-(phenanthrene-9-yl)phenyl}pyrimidine: compounds (1-7)>

[0109] In a nitrogen-purged reaction vessel, 5.0 g of 2,5-dichloropyrimidine, 50 mL of 1,4-dioxane, and 28.1 g of 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaborhexacyclopentane were added sequentially. Then, a solution obtained by dissolving 21.4 g of tripotassium phosphate in 15 mL of purified water was added, and the mixture was bubbled under nitrogen for 30 minutes. Next, 1.5 g of tris(dibenzylacetone)dipalladium and 1.9 g of tricyclohexylphosphine were added, and the mixture was stirred under reflux for 12 hours. After cooling to room temperature, 50 mL of methanol was added, and the precipitated solid was collected by filtration. 1.0 L of chlorobenzene was added to the solid, and the mixture was heated to 100 °C to dissolve the solid. Then, 10 g of silica gel and 10 g of activated clay were added, and the mixture was stirred for 1 hour. Insoluble components were removed by hot filtration, and the filtrate was concentrated. By recrystallizing the residue with chlorobenzene, 12.6 g of white powder of 2,5-bis{4-(phenanthrene-9-yl)phenyl}pyrimidine: compounds (1-7) was obtained (yield: 64%).

[0110] [Chemistry 5]

[0111]

[0112] The structure of the obtained white powder was identified using NMR.

[0113] use 1 H-NMR (THF-d8) detected the following 28 hydrogen signals.

[0114] δ(ppm)=9.33(2H), 8.80-8.94(6H), 7.99-8.06(6H), 7.60-7.85(14H).

[0115] [Example 2]

[0116] <Synthesis of 2,5-bis{4-(phenanthrene-9-yl)phenyl}pyridine: compounds (1-41)>

[0117] In Example 1, 2,5-dichloropyrimidine was replaced with 2,5-dibromopyridine, and the same operation was performed to obtain 11.5 g of white powder of 2,5-bis{4-(phenanthrene-9-yl)phenyl}pyridine:compound (1-41) (yield: 78%).

[0118] [Chemistry 6]

[0119]

[0120] The structure of the obtained white powder was identified using NMR.

[0121] use 1 H-NMR (THF-d8) detected the following 29 hydrogen signals.

[0122] δ(ppm)=9.14(1H), 8.81-8.89(4H), 8.39-8.41(2H), 8.22-8.23(1H), 8.12-8.14(1H), 7.95-8.01(6H), 7.80(2H), 7.56-7.79(12H).

[0123] [Example 3]

[0124] <5-{4-(dibenzofuran-3-yl)phenyl}-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine: Synthesis of Compounds (1-71)>

[0125] In a nitrogen-purged reaction vessel, 9.4 g of 2,5-dichloropyrimidine, 160 mL of toluene, 60 mL of ethanol, and 20.0 g of 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaborhecyclopentane were added sequentially. Then, a solution obtained by dissolving 10.9 g of potassium carbonate in 40 mL of purified water was added, and the mixture was bubbled under nitrogen for 30 minutes. Next, 0.6 g of tetra(triphenylphosphine)palladium(O) was added, and the mixture was stirred under reflux for 15 hours. After cooling to room temperature, the mixture was separated. The organic layer was washed sequentially with water and saturated brine, and then dried with anhydrous magnesium sulfate. The desiccant was removed by filtration, and the filtrate was concentrated. 200 mL of toluene was added to the residue, and the mixture was heated to 80°C. Then, 10 g of silica gel and 10 g of activated clay were added, and the mixture was stirred for 1 hour. Insoluble components were removed by filtration, and the filtrate was concentrated. Acetone was added to the residue, and the mixture was dispersed and washed to obtain 16.5 g of a white powder of 5-chloro-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine (yield: 86%).

[0126] 8.0 g of the obtained 5-chloro-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine was added to a reaction vessel purged with nitrogen. Then, 100 mL of 1,4-dioxane and 28.1 g of 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborhexacyclopentan-2-yl)phenyl}dibenzofuran were added sequentially. A solution obtained by dissolving 21.4 g of tripotassium phosphate in 15 mL of purified water was then added, and the mixture was bubbled under nitrogen for 30 minutes. Next, 0.2 g of tris(dibenzylacetone)dipalladium and 0.1 g of tricyclohexylphosphine were added, and the mixture was stirred under reflux for 13 hours. After cooling to room temperature, the precipitated solid was collected by filtration. Methanol and water were added to the solid, and the mixture was refluxed for 1 hour to disperse and wash it. The solid was collected, 750 mL of chlorobenzene was added, and the mixture was heated to 100°C to dissolve the solid. Then, 8 g of silica gel and 8 g of activated clay were added, and the mixture was stirred for 1 hour. Insoluble components were removed by hot filtration, and the filtrate was concentrated. The residue was recrystallized with chlorobenzene to obtain 10.5 g of white powder of 5-{4-(dibenzofuran-3-yl)phenyl}-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine: compound (1-71) (yield: 72%).

[0127] [Chemistry 7]

[0128]

[0129] The structure of the obtained white powder was identified using NMR.

[0130] use 1 H-NMR (THF-d8) detected the following 26 hydrogen signals.

[0131] δ(ppm)=9.28(2H), 8.76-8.92(4H), 7.96-8.18(9H), 7.36-7.86(11H).

[0132] [Example 4]

[0133] <5-{4-(phenanthrene-2-yl)phenyl}-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine: Synthesis of Compounds (1-74)>

[0134] In Example 3, 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborhexacyclopentan-2-yl)phenyl}dibenzofuran was replaced with 4,4,5,5-tetramethyl-2-{4-(phenanthrene-2-yl)phenyl}-1,3,2-dioxaborhexacyclopentanane, and the same operation was performed to obtain 8.6 g of white powder of 5-{4-(phenanthrene-2-yl)phenyl}-2-{4-(phenanthrene-9-yl)phenyl}pyrimidine:compound (1-74) (yield: 58%).

[0135] [Chemistry 8]

[0136]

[0137] The structure of the obtained white powder was identified using NMR.

[0138] use 1 H-NMR (THF-d8) detected the following 28 hydrogen signals.

[0139] δ(ppm)=9.31(2H), 8.78-8.93(6H), 8.35-8.36(1H), 7.91-8.13(9H), 7.85-7.87(2H), 7.60-7.76(8H).

[0140] [Example 5]

[0141] <2-{4-(phenanthrene-9-yl)phenyl}-5-{4-(1,10-phenanthroline-2-yl)phenyl}pyrimidine: Synthesis of compound (1-137)>

[0142] In Example 3, 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborhecyclopentan-2-yl)phenyl}dibenzofuran was replaced with 4,4,5,5-tetramethyl-2-{4-(1,10-phenanthroline-2-yl)phenyl}-1,3,2-dioxaborhecyclopentanane, and the same operation was performed to obtain 7.5 g of white powder of 2-{4-(phenanthroline-9-yl)phenyl}-5-{4-(1,10-phenanthroline-2-yl)phenyl}pyrimidine:compound (1-137) (yield: 46.8%).

[0143] [Chemistry 9]

[0144]

[0145] The structure of the obtained white powder was identified using NMR.

[0146] use 1 H-NMR (CDCl3) detected the following 26 hydrogen signals.

[0147] δ(ppm)=9.47(1H), 8.82(1H), 8.76(1H), 8.47(1H), 8.39(2H), 8.31(1H), 8.21(1H), 8.17(1H), 8.03(1 H), 8.00-7.89(6H), 7.86(1H), 7.78(1H), 7.74(2H), 7.70(2H), 7.66(1H), 7.61(1H), 7.56-7.50(2H).

[0148] [Example 6]

[0149] <Synthesis of 2,5-bis{4-(dibenzothiophene-4-yl)phenyl}pyrimidine: compounds (1-20)>

[0150] In Example 1, 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaborhecyclopentane was replaced with 4,4,5,5-tetramethyl-2-{4-(dibenzothiophene-4-yl)phenyl}-1,3,2-dioxaborhecyclopentane, and the same operation was performed to obtain 4.0 g of white powder of 2,5-bis{4-(dibenzothiophene-4-yl)phenyl}pyrimidine:compound (1-20) (yield: 40.0%).

[0151] [Chemistry 10]

[0152]

[0153] The structure of the obtained white powder was identified using NMR.

[0154] use 1 H-NMR (CDCl3) detected the following 24 hydrogen signals.

[0155] δ(ppm)=9.18(2H), 8.69(2H), 8.23(4H), 7.95(4H), 7.86(4H), 7.64-7.54(4H), 7.54-7.45(4H).

[0156] [Example 7]

[0157] <2,5-Bis{4-(1,10-phenanthroline-2-yl)phenyl}pyrimidine: Synthesis of Compound (1-154)>

[0158] In Example 1, 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaboranecyclopentane was replaced with 4,4,5,5-tetramethyl-2-{4-(1,10-phenanthrene-2-yl)phenyl}-1,3,2-dioxaboranecyclopentane, and the same operation was performed to obtain 10.6 g of white powder of 2,5-bis{4-(1,10-phenanthrene-2-yl)phenyl}pyrimidine:compound (1-154) (yield: 59.5%).

[0159] [Chemistry 11]

[0160]

[0161] The structure of the obtained white powder was identified using NMR.

[0162] use 1 H-NMR (CDCl3) detected the following 24 hydrogen signals.

[0163] δ(ppm)=9.28(1H), 8.80(1H), 8.75(1H), 8.50(2H), 8.33(1H), 8.27(1H), 8.18(1H), 8.03(1H), 7.95-7.74(8H), 7.72-7.54(7H).

[0164] [Example 8]

[0165] <5-(dibenzofuran-3-yl)-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: Synthesis of compounds (1-89)>

[0166] In a nitrogen-purged reaction vessel, 30.0 g of 2,5-dichloropyrimidine, 66.0 g of 2-9,9'-spirobis[9H]fluoreneboronic acid, 2.1 g of tetrakis(triphenylphosphine)palladium(O), and 38.0 g of potassium carbonate were added and refluxed in a toluene / ethanol / water mixture overnight. After natural cooling, toluene / water was added, and the organic layer was collected by extraction and separation, and concentrated to obtain the crude product. The crude product was purified by column chromatography (support: silica gel, eluent: dichloromethane / n-heptane) to obtain 39.0 g of a white powder of 5-chloro-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine (yield: 49.6%).

[0167] 9.5 g of the obtained 5-chloro-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine was added to a nitrogen-purged reaction vessel, followed by 5.2 g of (dibenzofuran-3-yl)boric acid, 6.1 g of tripotassium phosphate, 0.2 g of tris(dibenzylacetone)dipalladium(0), 0.1 g of tricyclohexylphosphine, 100 mL of 1,4-dioxane, and 30 mL of purified water. The mixture was stirred under reflux overnight. After natural cooling, methanol was added, and the precipitated solid was collected by filtration to obtain the crude product. The crude product was purified by crystallization using a chlorobenzene / acetone mixed solvent to obtain 8.4 g of white powder of 5-(dibenzofuran-3-yl)-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: compound (1-89) (yield: 68.0%).

[0168] [Chemistry 12]

[0169]

[0170] The structure of the obtained white powder was identified using NMR.

[0171] use 1 H-NMR (CDCl3) detected the following 24 hydrogen signals.

[0172] δ(ppm)=8.97(2H), 8.61(1H), 8.04(1H), 8.00(1H), 7.98(1H), 7.92(1H), 7.90(1H), 7.88(2H), 7 .74(1H), 7.59(1H), 7.53(1H), 7.49(1H), 7.39(4H), 7.14(1H), 7.11(2H), 6.79(2H), 6.74(1H).

[0173] [Example 9]

[0174] <5-{4-(naphthyl-1-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: Synthesis of compound (1-142)>

[0175] In Example 8, (dibenzofuran-3-yl)boronic acid was replaced with 4-(naphth-1-yl)phenylboronic acid, and the same operation was performed to obtain 9.8 g of white powder of 5-{4-(naphth-1-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: compound (1-142) (yield: 71.0%).

[0176] [Chemistry 13]

[0177]

[0178] The structure of the obtained white powder was identified using NMR.

[0179] use 1 H-NMR (CDCl3) detected the following 28 hydrogen signals.

[0180] δ(ppm)=8.98(2H), 8.62(1H), 8.01(1H), 7.90(7H), 7.65(4H), 7.58-7.34(7H), 7.14(1H), 7.11(2H), 6.79(2H), 6.74(1H).

[0181] [Example 10]

[0182] <Synthesis of 5-{4-(naphthyl-2-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine; Compound (1-143)>

[0183] In Example 8, (dibenzofuran-3-yl)boronic acid was replaced with 4-(naphth-2-yl)phenylboronic acid, and the same operation was performed to obtain 10.6 g of white powder of 5-{4-(naphth-2-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: compound (1-143) (yield: 76.3%).

[0184] [Chemistry 14]

[0185]

[0186] The structure of the obtained white powder was identified using NMR.

[0187] use 1 H-NMR (CDCl3) detected the following 28 hydrogen signals.

[0188] δ(ppm)=8.95(2H), 8.60(1H), 8.07(1H), 8.00(1H), 7.96-7.81(9H), 7.76(1H) ), 7.67(2H), 7.51(2H), 7.38(3H), 7.14(1H), 7.11(2H), 6.79(2H), 6.74(1H).

[0189] [Example 11]

[0190] <5-{4-(benzothiophene-2-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: Synthesis of Compounds (1-146)>

[0191] In Example 8, (dibenzofuran-3-yl)boronic acid was replaced with 4,4,5,5-tetramethyl-2-{4-(benzothiophen-2-yl)phenyl}-1,3,2-dioxaborane, and the same operation was performed to obtain 9.4 g of white powder of 5-{4-(benzothiophen-2-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine:compound (1-146) (yield: 70.0%).

[0192] [Chemistry 15]

[0193]

[0194] The structure of the obtained white powder was identified using NMR.

[0195] use 1 H-NMR (CDCl3) detected the following 26 hydrogen signals.

[0196] δ(ppm)=8.93(2H), 8.60(1H), 8.00(1H), 7.92(1H), 7.90-7.81(6H), 7.79( 1H), 7.62(3H), 7.43-7.30(5H), 7.14(1H), 7.11(2H), 6.78(2H), 6.74(1H).

[0197] [Example 12]

[0198] <5-{4-(benzoxazol-2-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: Synthesis of compound (1-147)>

[0199] In Example 8, (dibenzofuran-3-yl)boronic acid was replaced with 4,4,5,5-tetramethyl-2-{4-(benzoxazol-2-yl)phenyl}-1,3,2-dioxaborhecyclopentane, and the same operation was performed to obtain 12.5 g of white powder of 5-{4-(benzoxazol-2-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine:compound (1-147) (yield: 91.2%).

[0200] [Chemistry 16]

[0201]

[0202] The structure of the obtained white powder was identified using NMR.

[0203] use 1 H-NMR (CDCl3) detected the following 25 hydrogen signals.

[0204] δ(ppm)=8.96(2H), 8.61(1H), 8.37(2H), 8.00(1H), 7.92(1H), 7.90(1H), 7.88(2H), 7.8 0(1H), 7.72(2H), 7.61(1H), 7.42-7.35(5H), 7.15(1H), 7.11(2H), 6.78(2H), 6.74(1H).

[0205] [Example 13]

[0206] <5-{4-(benzothiazol-2-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: Synthesis of Compounds (1-148)>

[0207] In Example 8, (dibenzofuran-3-yl)boronic acid was converted to 4,4,5,5-tetramethyl-2-{4-(benzothiazol-2-yl)phenyl}-1,3,2-dioxaborhecyclopentane, and the same operation was performed to obtain 11.5 g of white powder of 5-{4-(benzothiazol-2-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine:compound (1-148) (yield: 81.6%).

[0208] [Chemistry 17]

[0209]

[0210] The structure of the obtained white powder was identified using NMR.

[0211] use 1 H-NMR (CDCl3) detected the following 25 hydrogen signals.

[0212] δ(ppm)=8.95(2H), 8.61(1H), 8.22(2H), 8.10(1H), 8.00(1H), 7.92(2H), 7.89(1H), 7.8 8(2H), 7.69(2H), 7.52(1H), 7.44-7.35(4H), 7.15(1H), 7.11(2H), 6.78(2H), 6.75(1H).

[0213] [Example 14]

[0214] <5-{4-(9-phenyl-carbazole-3-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: Synthesis of compound (1-149)>

[0215] In Example 8, (dibenzofuran-3-yl)boronic acid was converted to 4,4,5,5-tetramethyl-2-{4-(9-phenyl-carbazole-3-yl)phenyl}-1,3,2-dioxaboranecyclopentane, and the same operation was performed to obtain 10.1 g of pale yellow powder of 5-{4-(9-phenyl-carbazole-3-yl)phenyl}-2-(9,9'-spirobis[9H]fluorene-2-yl)pyrimidine: compound (1-149) (yield: 62.9%).

[0216] [Chemistry 18]

[0217]

[0218] The structure of the obtained pale yellow powder was identified using NMR.

[0219] use 1 H-NMR (CDCl3) detected the following 33 hydrogen signals.

[0220] δ(ppm)=8.97(2H), 8.61(1H), 8.38(1H), 8.20(1H), 8.00(1H), 7.92(1H), 7.90(1H), 7.88(2H), 7.85(2H), 7.7 0-7.56(7H), 7.50(1H), 7.48(1H), 7.43(2H), 7.38(3H), 7.32(1H), 7.14(1H), 7.11(2H), 6.79(2H), 6.74(1H).

[0221] [Example 15]

[0222] <2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(naphthyl-2-yl)phenyl}pyrimidine: Synthesis of Compounds (1-150)>

[0223] In Example 3, 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborhecyclopentan-2-yl)phenyl}dibenzofuran was replaced with 4,4,5,5-tetramethyl-2-{3,5-bis(naphthyl-2-yl)phenyl}-1,3,2-dioxaborhecyclopentanane, and the same operation was performed to obtain 1.8 g of white powder of 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(naphthyl-2-yl)phenyl}pyrimidine:compound (1-150) (yield: 22.2%).

[0224] [Chemistry 19]

[0225]

[0226] The structure of the obtained white powder was identified using NMR.

[0227] use 1 H-NMR (CDCl3) detected the following 32 hydrogen signals.

[0228] δ(ppm)=9.25(2H), 8.81(1H), 8.75(1H), 8.69(2H), 8.22(2H), 8.16(1H), 8. 04-7.88(12H), 7.77(1H), 7.74(2H), 7.70(2H), 7.64(1H), 7.60-7.51(5H).

[0229] [Example 16]

[0230] <2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(quinolin-3-yl)phenyl}pyrimidine: Synthesis of compound (1-151)>

[0231] In Example 3, 3-{4-(4,4,5,5-tetramethyl-1,3,2-dioxaborhecyclopentan-2-yl)phenyl}dibenzofuran was replaced with 4,4,5,5-tetramethyl-2-{3,5-bis(quinoline-3-yl)phenyl}-1,3,2-dioxaborhecyclopentanane, and the same operation was performed to obtain 4.3 g of white powder of 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(quinoline-3-yl)phenyl}pyrimidine:compound (1-151) (yield: 47.6%).

[0232] [Chemistry 20]

[0233]

[0234] The structure of the obtained white powder was identified using NMR.

[0235] use 1 H-NMR (CDCl3) detected the following 30 hydrogen signals.

[0236] δ(ppm)=9.34(2H), 9.24(2H), 8.80(1H), 8.74(1H), 8.69(2H), 8.49(2H), 8.22(2H), 8.13(1H), 8.0 3(2H), 8.00(1H), 7.97(2H), 7.93(1H), 7.80(2H), 7.77(1H), 7.74(2H), 7.72-7.61(5H), 7.57(1H).

[0237] [Example 17]

[0238] <2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(naphthyl-2-yl)phenyl}pyridine: Synthesis of compound (1-152)>

[0239] In a nitrogen-purged reaction vessel, 9.3 g of 2,5-dichloropyridine, 10.0 g of 4,4,5,5-tetramethyl-2-{4-(phenanthrene-9-yl)phenyl}-1,3,2-dioxaborhexacyclopentane, 0.8 g of tetra(triphenylphosphine)palladium(0), and 10.9 g of potassium carbonate were added and refluxed in a toluene / ethanol / water mixture for 5 hours. After natural cooling, toluene / water was added, and the organic layer was collected by extraction and separation, and concentrated to obtain the crude product. The crude product was purified by column chromatography (support: silica gel, eluent: toluene / n-heptane) to obtain 9.6 g of a white powder of 5-chloro-2-{4-(phenanthrene-9-yl)phenyl}pyridine (yield: 81.5%).

[0240] 5.0 g of the obtained 5-chloro-2-{4-(phenanthrene-9-yl)phenyl}pyridine was added to a reaction vessel purged with nitrogen. Then, 6.7 g of 4,4,5,5-tetramethyl-2-{3,5-bis(naphthyl-2-yl)phenyl}-1,3,2-dioxaborhecyclopentane, 0.4 g of tetra(triphenylphosphine)palladium(0), and 2.5 g of potassium carbonate were added. The mixture was refluxed and stirred overnight in a toluene / ethanol / water mixture. After natural cooling, methanol was added, and the precipitated solid was collected by filtration to obtain the crude product. The crude product was purified by recrystallization using toluene to obtain 6.7 g of a white powder of 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(naphthyl-2-yl)phenyl}pyridine: compound (1-152) (yield: 83.3%).

[0241] [Chemistry 21]

[0242]

[0243] The structure of the obtained white powder was identified using NMR.

[0244] use 1 H-NMR (CDCl3) detected the following 33 hydrogen signals.

[0245] δ(ppm)=9.17(1H), 8.80(1H), 8.75(1H), 8.25(2H), 8.22(2H), 8.18(1H), 8.12(1H), 8. 04-7.95(8H), 7.95-7.88(5H), 7.76(1H), 7.74-7.66(4H), 7.64(1H), 7.60-7.51(5H).

[0246] [Example 18]

[0247] <Synthesis of 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(quinolin-3-yl)phenyl}pyridine; Compound (1-153)>

[0248] In Example 17, 4,4,5,5-tetramethyl-2-{3,5-bis(naphthyl-2-yl)phenyl}-1,3,2-dioxaborhecyclopentane was replaced with 4,4,5,5-tetramethyl-2-{3,5-bis(quinoline-3-yl)phenyl}-1,3,2-dioxaborhecyclopentane, and the same operation was performed to obtain 5.3 g of white powder of 2-{4-(phenanthrene-9-yl)phenyl}-5-{3,5-bis(quinoline-3-yl)phenyl}pyridine:compound (1-153) (yield: 73.0%).

[0249] [Chemistry 22]

[0250]

[0251] The structure of the obtained white powder was identified using NMR.

[0252] use 1 H-NMR (CDCl3) detected the following 31 hydrogen signals.

[0253] δ(ppm)=9.34(2H), 9.16(2H), 8.80(1H), 8.74(1H), 8.48(2H), 8.28(2H), 8.21(2H), 8.17(1H) , 8.08(1H), 8.05(2H), 8.00(2H), 7.96(2H), 7.92(1H), 7.79(2H), 7.74-7.60(7H), 7.56(1H).

[0254] [Example 19]

[0255] For heterocyclic compounds represented by general formula (1), the glass transition temperature (Tg) and melting point were determined using a high-sensitivity differential scanning calorimeter (manufactured by Bruker-AXS, DSC3100SA). The results are summarized in Table 1.

[0256] [Table 1]

[0257]

[0258] Thus, the heterocyclic compound represented by the general formula (1) of the present invention has a glass transition temperature (Tg) of 100°C or higher, or no glass transition temperature (Tg) is observed, indicating that the film is in a stable state.

[0259] [Example 20]

[0260] A vapor-deposited film with a thickness of 80 nm was fabricated on a silicon substrate using a heterocyclic compound represented by general formula (1). The refractive index n at wavelengths of 450 nm and 750 nm was measured using a spectrophotometer (Filmetrics F10-RT-UV). Additionally, for comparison, measurements were performed on comparative compounds (2-1) and Alq3 with the following structural formulas. The results are summarized in Table 2.

[0261] [Chemistry 23]

[0262]

[0263] [Table 2]

[0264]

[0265] Thus, the refractive index n of the heterocyclic compound represented by the general formula (1) of the present invention has a value equal to or greater than that of Alq3 and the comparative compound (2-1) in the wavelength range of 450 nm to 750 nm. This means that by using the heterocyclic compound represented by the general formula (1) of the present invention as the constituent material of the capping layer, it is possible to expect an improvement in the light extraction efficiency in the organic EL element.

[0266] [Example 21]

[0267] Organic EL components such as Figure 12 As shown, the product on which a reflective ITO electrode is pre-formed as a metal anode 2 is mounted on a glass substrate 1, by sequentially depositing a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, a cathode 8, and a capping layer 9.

[0268] Specifically, for a product on a glass substrate 1 having sequentially formed a 50 nm thick ITO film, a 100 nm thick silver alloy reflective film, and a 5 nm thick ITO film as a metal anode 2, after ultrasonic cleaning in isopropanol for 20 minutes, it is dried for 10 minutes on a hot plate heated to 250°C. Then, after a 2-minute UV ozone treatment, the glass substrate with ITO is mounted in a vacuum evaporation machine, and the pressure is reduced to below 0.001 Pa. Next, in a manner covering the metal anode 2, a binary evaporation process is performed using an electron acceptor (Acceptor-1) of the following structure and a compound (3-1) of the following structure at a evaporation rate ratio of (Acceptor-1):compound (3-1) = 3:97 to form a hole injection layer 3 with a film thickness of 10 nm. On this hole injection layer 3, a hole transport layer 4 is formed using a compound (3-1) of the following structure with a film thickness of 140 nm. On the hole transport layer 4, compound (3-2) and compound (3-3) of the following structural formulas were subjected to binary vapor deposition at a deposition rate ratio of compound (3-2):compound (3-3) = 5:95 to form a light-emitting layer 5 with a film thickness of 20 nm. On the light-emitting layer 5, compound (3-4) and compound (3-5) of the following structural formulas were subjected to binary vapor deposition at a deposition rate ratio of compound (3-4):compound (3-5) = 50:50 to form an electron transport layer 6 with a film thickness of 30 nm. On the electron transport layer 6, an electron injection layer 7 was formed using lithium fluoride with a film thickness of 1 nm. On the electron injection layer 7, a cathode 8 was formed using a magnesium-silver alloy with a film thickness of 12 nm. Finally, a capping layer 9 was formed using compound (1-7) of Example 1 with a film thickness of 60 nm. The manufactured organic EL element was subjected to characteristic measurements in atmospheric conditions at room temperature.

[0269] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0270] [Chemistry 24]

[0271]

[0272] [Chemistry 25]

[0273]

[0274] [Chemistry 26]

[0275]

[0276] [Chemistry 27]

[0277]

[0278] [Chemistry 28]

[0279]

[0280] [Chemistry 29]

[0281]

[0282] [Chemistry 30]

[0283]

[0284] [Example 22]

[0285] Except that in Example 21, compounds (1-41) of Example 2 were used instead of compounds (1-7) of Example 1 as the capping layer 9, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0286] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0287] [Chemistry 31]

[0288]

[0289] [Example 23]

[0290] Except that in Example 21, the compound (1-71) of Example 3 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0291] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0292] [Chemistry 32]

[0293]

[0294] [Example 24]

[0295] Except that in Example 21, compound (1-74) of Example 4 was used as the capping layer 9 instead of compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0296] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0297] [Chemistry 33]

[0298]

[0299] [Example 25]

[0300] Except that in Example 21, compound (1-137) of Example 5 was used instead of compound (1-7) of Example 1 as capping layer 9, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0301] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0302] [Chemistry 34]

[0303]

[0304] [Example 26]

[0305] Except that in Example 21, compounds (1-20) of Example 6 were used instead of compounds (1-7) of Example 1 as the capping layer 9, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0306] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0307] [Chemistry 35]

[0308]

[0309] [Example 27]

[0310] Except that in Example 21, compound (1-154) of Example 7 was used instead of compound (1-7) of Example 1 as capping layer 9, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0311] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0312] [Chemistry 36]

[0313]

[0314] [Example 28]

[0315] Except that in Example 21, compounds (1-89) from Example 8 were used instead of compounds (1-7) from Example 1 as the capping layer 9, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0316] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0317] [Chemistry 37]

[0318]

[0319] [Example 29]

[0320] Except that in Example 21, compounds (1-142) of Example 9 were used instead of compounds (1-7) of Example 1 as the capping layer 9, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0321] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0322] [Chemistry 38]

[0323]

[0324] [Example 30]

[0325] Except that in Example 21, the compound (1-143) of Example 10 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0326] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0327] [Chemistry 39]

[0328]

[0329] [Example 31]

[0330] Except that in Example 21, the compound (1-146) of Example 11 was used instead of the compound (1-7) of Example 1 as the capping layer 9, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0331] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0332] [Chemistry 40]

[0333]

[0334] [Example 32]

[0335] Except that in Example 21, the compound (1-147) of Example 12 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0336] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0337] [Chemistry 41]

[0338]

[0339] [Example 33]

[0340] Except that in Example 21, the compound (1-148) of Example 13 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0341] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0342] [Chemistry 42]

[0343]

[0344] [Example 34]

[0345] Except that in Example 21, the compound (1-149) of Example 14 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0346] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0347] [Chemistry 43]

[0348]

[0349] [Example 35]

[0350] Except that in Example 21, the compound (1-150) of Example 15 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0351] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0352] [Chemistry 44]

[0353]

[0354] [Example 36]

[0355] Except that in Example 21, the compound (1-151) of Example 16 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0356] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0357] [Chemistry 45]

[0358]

[0359] [Example 37]

[0360] Except that in Example 21, the compound (1-152) of Example 17 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0361] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0362] [Chemistry 46]

[0363]

[0364] [Example 38]

[0365] Except that in Example 21, the compound (1-153) of Example 18 was used as the capping layer 9 instead of the compounds (1-7) of Example 1, the organic EL element was manufactured under the same conditions. The characteristics of the manufactured organic EL element were measured in air at room temperature.

[0366] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0367] [Chemistry 47]

[0368]

[0369] [Comparative Example 1]

[0370] For comparison, organic EL elements were manufactured under the same conditions, except that Alq3 was used as the capping layer 9 instead of compounds (1-7) of Example 1 in Example 21. The characteristics of the manufactured organic EL elements were measured in air at room temperature.

[0371] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0372] [Comparative Example 2]

[0373] For comparison, except that in Example 21, comparative compound (2-1) was used instead of compounds (1-7) of Example 1 as capping layer 9, organic EL elements were manufactured under the same conditions. The characteristics of the manufactured organic EL elements were measured in air at room temperature.

[0374] The results of measuring the light emission characteristics of the manufactured organic EL elements after applying a DC voltage are summarized in Table 3.

[0375] The results of measuring the device lifetime using the organic EL devices manufactured in Examples 21-38 and Comparative Examples 1-2 are summarized in Table 3. Regarding device lifetime, a measurement of 10 mA / cm was taken as the baseline. 2 The constant current drive was measured until the light decayed to 95% of the initial brightness when it was set to 100% (95% decay).

[0376] [Table 3]

[0377]

[0378] As shown in Table 3, the current density is 10 mA / cm². 2The driving voltage was approximately the same in the devices of Comparative Examples 1 and 2 as in the devices of Examples 21-38 using a heterocyclic compound represented by the general formula (1) of the present invention as a capping layer. However, the devices of Examples 21-38 showed significant improvements in brightness, luminous efficiency, power efficiency, and device lifetime compared to the devices of Comparative Examples 1 and 2. This indicates that the heterocyclic compound represented by the general formula (1) of the present invention is a suitable material for use as a capping layer, and due to the high refractive index of the capping layer, the light extraction efficiency of the organic EL device can be significantly improved.

[0379] Industrial availability

[0380] The heterocyclic compound represented by general formula (1) of the present invention has a high refractive index, which can significantly improve the light extraction efficiency and the film state is stable. Therefore, it is an excellent compound suitable for use as a capping layer for organic EL elements. Organic EL elements manufactured using the heterocyclic compound represented by general formula (1) of the present invention can achieve high efficiency. In addition, by using the heterocyclic compound represented by general formula (1) of the present invention, which does not have absorption in the blue, green and red wavelength regions, it is particularly suitable for displaying images with good color purity, vividness and brightness. For example, it can be developed for applications such as home electrical products and lighting.

[0381] Explanation of reference numerals in the attached figures

[0382] 1 Glass substrate

[0383] 2 Metal Anode

[0384] 3 Hole Injection Layer

[0385] 4 Hole transport layer

[0386] 5 light-emitting layers

[0387] 6 Electron transport layer

[0388] 7 Electron Injection Layer

[0389] 8 cathodes

[0390] 9 capping layers

Claims

1. Heterocyclic compounds represented by the following general formula (1-a): In the formula, L1 and L2 may be the same or different, representing a single bond and an unsubstituted 1,4-phenylene. Ar1 and Ar2 may be the same or different, representing a substituted phenyl, a substituted or unsubstituted naphthyl, a substituted or unsubstituted phenanthryl, a substituted or unsubstituted spirodifluorenyl, a substituted or unsubstituted benzothiophene, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted dibenzothiophene, a substituted or unsubstituted benzoxazolyl, or a substituted or unsubstituted benzothiazolyl. In this case, L1 and L2 are not both single bonds, and at least one of L1 and L2 is an unsubstituted 1,4-phenylene. When Ar1 and Ar2 have substituents, the substituents are selected from unsubstituted alkyl groups having 1 to 6 carbon atoms, unsubstituted naphthyl, unsubstituted phenanthrolinyl, and unsubstituted quinolinyl.

2. An organic thin film comprising the heterocyclic compound according to claim 1, characterized in that, The refractive index is above 1.70 in the wavelength range of 450nm to 750nm.

3. An organic electroluminescent element, comprising at least an anode electrode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode electrode, and a capping layer in sequence, characterized in that, The capping layer is an organic thin film containing the heterocyclic compound according to claim 1.

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