Pyrimidine compound and organic electroluminescent device

Abstract

The purpose of one mode of the present disclosure is to provide: a novel pyrimidine compound for forming an organic electroluminescent element that exerts high electric current efficiency; and an organic electroluminescent element material and an organic electroluminescent element containing said pyrimidine compound.　Said mode of the present disclosure is achieved by: a pyrimidine compound having a specific structure represented by formula (1); and an organic electroluminescent element material and an organic electroluminescent element containing said pyrimidine compound.

Description

[Technical field]

[0001] The present disclosure relates to a pyrimidine compound and an organic electroluminescent device. [Background technology]

[0002] Organic electroluminescent devices have begun to be put to practical use, mainly for small mobile applications. However, further expansion of applications requires improved performance, and materials with high current efficiency, low driving voltage, high luminous efficiency, and long life are required. Patent documents 1 and 2 disclose pyridine compounds having 1,3,5-triazine as a partial structure, which are materials for organic electroluminescent devices with long life and excellent luminous properties. Patent documents 2 to 5 disclose pyrimidine compounds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-314503 A [Patent Document 2] WO2020 / 0117026 publication [Patent Document 3] JP 2011-084553 A [Patent Document 4] Korean Patent Publication No. 2017 / 0093023 [Patent Document 5] Korean Patent Publication No. 2017 / 0113397 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to expand the applications of pyrimidine compounds related to organic electroluminescent devices and the environments in which they can be used, it is necessary to improve three properties, i.e., current efficiency, luminous efficiency, and life characteristics. However, the compounds described in Patent Documents 1 to 5 cannot be said to fully satisfy these requirements, and there is a demand for compounds that achieve a higher level of current efficiency, in particular.

[0005] Therefore, one aspect of the present disclosure is directed to providing a new pyrimidine compound that may have particularly high current efficiency and contributes to the formation of an organic electroluminescent device exhibiting high levels of current efficiency and luminous efficiency characteristics.

[0006] Furthermore, still another aspect of the present disclosure is directed to providing an organic electroluminescent device that has high current efficiency and high luminous efficiency and can be used in a variety of applications or under a variety of environments. [Means for solving the problem]

[0007] Embodiments of the present disclosure are described below. 1. A pyrimidine compound according to one embodiment of the present disclosure is a pyrimidine compound represented by formula (1).

[0008] [ka] In formula (1), Ar 1 teeth, an aromatic group having 5 to 20 carbon atoms, which may be a monocyclic ring, a condensed ring, or a ring or rings linked thereto; The aromatic group is formed by the following ring alone or in combination: Aromatic hydrocarbon rings, Heteroaromatic rings containing Group 16 elements, and Heteroaromatic rings formed exclusively of six-membered rings and containing one N as a heteroatom; L is An aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, or represents a heteroaromatic group having 5 to 17 carbon atoms, which is formed only of 6-membered rings and consists only of C, H and N, and which may have a substituent; Ar 2 is a structure represented by formula (2-A) or (2-B), The dotted line indicates the site of attachment to L; X 11 ~X 14 and X 21~X 24 represents C-Ra, C-Rb or N; X 11 ~X 14 and X 21 ~X 24 Two or more of the following cannot be N at the same time; X 11 ~X 14 Of these, three or more cannot be C-Ra at the same time; X 21 ~X 24 Of these, two or more cannot be C-Ra at the same time; R 1 , R 2 and Ra is an aromatic group having 5 to 20 carbon atoms, which may be a monocyclic ring, a condensed ring, or a ring or rings linked thereto; The aromatic group is formed by the following ring alone or in combination: Aromatic hydrocarbon rings, A heteroaromatic ring having a Group 16 element and not containing two or more N atoms, and Heteroaromatic rings formed exclusively of six-membered rings and containing one N as a heteroatom; Rb is Hydrogen, deuterium, alkyl groups having 1 to 10 carbon atoms; Two or more of Ra and Rb may be different from each other;

[0009] [ka] a represents an integer from 0 to 3; b represents an integer from 1 to 4; a+b is 3 or 4; c represents an integer from 1 to 3; Ar 1 , Ar 2 If there are two or more Ls, multiple Ar 1 , Ar 2 , L may be different from each other; Ar 1 , Ar 2 , L, R 1 , R 2, Ra and Rb may be substituted with an alkyl group having 1 to 10 carbon atoms or a CN group, and these are Ar 1 , L, R 1 , R 2 and the number of carbon atoms of the aromatic groups forming Ra is not included in the number of carbon atoms. However, Ar 1 and Ar 2 does not have the following groups: The dotted lines indicate the points of attachment to other groups.

[0010] [ka]

[0011] 2. The pyrimidine compound according to the above 1, wherein the formula (2-A) or (2-B) is any one of the following formulae (2-1) to (2-8): During the ceremony, The dotted line indicates the site of attachment to L; X 1 ~X 4 represents CH or N, and X 1 ~X 4 Two or more of the following cannot be N at the same time; R 3 is R 1 and R 2 is synonymous with.

[0012] [ka] 3. The pyrimidine compound according to claim 1, wherein a+b is 3. 4. The pyrimidine compound according to claim 1, wherein L is optionally substituted phenylene, optionally substituted naphthylene, or optionally substituted pyridylene. 5. The pyrimidine compound according to claim 1, wherein L is phenylene, naphthylene, or pyridylene. 6. The pyrimidine compound according to 1 above, wherein L is selected from formulae (L-1) to (L-16). In the formula, the dotted line represents a pyrimidine moiety, or Ar 2 Represents the bonding point with.

[0013] [ka] 7. Ar 2 The pyrimidine compound according to the above item 2, wherein the pyrimidine compound is (2-1) to (2-3) or (2-5) to (2-8). 8. R 1 , R 2 but, an aromatic group having 5 to 20 carbon atoms, which may be a monocyclic ring, a condensed ring, or a ring or rings linked thereto; The aromatic group is formed by the following ring alone or in combination: an aromatic hydrocarbon ring, and A heteroaromatic ring having a Group 16 element and not containing two or more N atoms. The pyrimidine compound described in 1 above. 9. R 1 ~R 2 is a monocyclic or condensed ring, or an aromatic hydrocarbon group having 6 to 20 carbon atoms which may be linked thereto. 10. Ar 1 The pyrimidine compound according to 1 above, wherein the ring constituting the formula is benzene, naphthalene, phenanthrene, pyridine, or quinoline. 11. The pyrimidine compound according to 1 above, which is any one of (E1) to (E19) and (E21) below.

[0014] [ka] 12. An organic electroluminescent device having one or more organic thin film layers, including at least an emitting layer, between an anode and a cathode, wherein at least one of the organic thin film layers contains the pyrimidine compound described in any one of 1 to 11 above. Effect of the Invention

[0015] According to one embodiment of the present disclosure, it is possible to provide a pyrimidine compound suitable for forming an organic electroluminescent device exhibiting high current efficiency, high luminous efficiency characteristics, and long life characteristics at a high level.

[0016] According to another aspect of the present disclosure, a material for an organic electroluminescent element containing the pyrimidine compound and an electron transport material for an organic electroluminescent element can be provided. Furthermore, according to another aspect of the present disclosure, an organic electroluminescent element that exhibits low driving voltage, high luminous efficiency, and long life characteristics and can be used for various applications can be provided. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a layered structure of an organic electroluminescence element according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing another example of a laminate structure (structure of Element Example 1) of an organic electroluminescence element according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The pyrimidine compounds according to each aspect of the present disclosure will be described in detail below. A pyrimidine compound according to one embodiment of the present disclosure is represented by formula (1).

[0019] [ka] In formula (1), Ar 1 teeth, an aromatic group having 5 to 20 carbon atoms, which may be a monocyclic ring, a condensed ring, or a ring or rings linked thereto; The aromatic group is formed by the following ring alone or in combination: Aromatic hydrocarbon rings, Heteroaromatic rings containing Group 16 elements, and Heteroaromatic rings formed exclusively of six-membered rings and containing one N as a heteroatom; L is An aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, or represents a heteroaromatic group having 5 to 17 carbon atoms, which is formed only of 6-membered rings and consists only of C, H and N, and which may have a substituent; Ar 2 is a structure represented by formula (2-A) or (2-B), The dotted line indicates the site of attachment to L; X 11 ~X 14 and X 21 ~X 24 represents C-Ra, C-Rb or N; X 11 ~X 14 and X 21 ~X 24 Two or more of the following cannot be N at the same time; X 11 ~X 14 Of these, three or more cannot be C-Ra at the same time; X 21 ~X 24 Of these, two or more cannot be C-Ra at the same time; R 1 , R 2 and Ra is an aromatic group having 5 to 20 carbon atoms, which may be a monocyclic ring, a condensed ring, or a ring or rings linked thereto; The aromatic group is formed by the following ring alone or in combination: Aromatic hydrocarbon rings, A heteroaromatic ring having a Group 16 element and not containing two or more N atoms, and Heteroaromatic rings formed exclusively of six-membered rings and containing one N as a heteroatom; Rb is Hydrogen, deuterium, alkyl groups having 1 to 10 carbon atoms; Two or more of Ra and Rb may be different from each other;

[0020] [ka] a represents an integer from 0 to 3; b represents an integer from 1 to 4; a+b is 3 or 4; c represents an integer from 1 to 3; Ar 1 , Ar 2 If there are two or more Ls, multiple Ar 1 , Ar 2, L may be different from each other; Ar 1 , Ar 2 , L, R 1 , R 2 , Ra and Rb may be substituted with an alkyl group having 1 to 10 carbon atoms or a CN group, and these are Ar 1 , L, R 1 , R 2 and the number of carbon atoms of the aromatic groups forming Ra is not included in the number of carbon atoms. However, Ar 1 and Ar 2 does not have the following groups: The dotted lines indicate the points of attachment to other groups.

[0021] [ka]

[0022] [Ar 1 About Ar 1 is a monocyclic or condensed ring, or an aromatic group having 5 to 20 carbon atoms which may be linked together, and the aromatic group is formed by the following ring alone or in combination: Aromatic hydrocarbon rings, Heteroaromatic rings containing Group 16 elements, and heteroaromatic rings formed exclusively of six-membered rings and containing one N as a heteroatom.

[0023] Ar 1 is preferably an aromatic group having 6 to 18 carbon atoms, and more preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms.

[0024] Ar 1 is preferably an optionally substituted phenyl group, an optionally substituted biphenylyl group, or an optionally substituted naphthyl group. 1 may be substituted with one or more groups selected from the group consisting of a phenyl group, a biphenylyl group, a naphthyl group, a pyridyl group, a cyano group, and a methyl group.

[0025] [About L] L represents an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, or a heteroaromatic group having 5 to 17 carbon atoms which is formed only of a 6-membered ring and consists only of C, H and N, and which may have a substituent.

[0026] L is preferably an aromatic hydrocarbon group having 6 to 16 carbon atoms which may have a substituent, and more preferably an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have a substituent. Furthermore, L is preferably a heteroaromatic group having 5 to 15 carbon atoms which is formed only of a 6-membered ring and consists only of C, H and N, and may have a substituent, and more preferably a heteroaromatic group having 5 to 9 carbon atoms which is formed only of a 6-membered ring and consists only of C, H and N.

[0027] It is preferred that L is optionally substituted phenylene, optionally substituted naphthylene, or optionally substituted pyridylene, and it is further preferred that L is phenylene, naphthylene, or pyridylene.

[0028] It is particularly preferable that L is selected from the formulae (L-1) to (L-16). In the formula, the dotted line represents a pyrimidine moiety, or Ar 2 Represents the bonding point with.

[0029] [ka]

[0030] [Ar 2 About Ar 2 is a structure represented by the following formula (2-A) or (2-B), in which the dotted line represents the bonding site with L; X 11 ~X 14 and X 21 ~X 24 represents C-Ra, C-Rb or N; X 11 ~X 14 and X 21 ~X 24 Two or more of the following cannot be N at the same time; X 11 ~X 14 Of these, three or more cannot be C-Ra at the same time; X 21 ~X 24 Of these, two or more cannot be C-Ra at the same time;

[0031] R 1 , R 2 and Ra represent a monocyclic, condensed, or an aromatic group having 5 to 20 carbon atoms which may be linked, and the aromatic group is formed by the following ring alone or in combination: Aromatic hydrocarbon rings, A heteroaromatic ring having a Group 16 element and not containing two or more N atoms; Heteroaromatic rings containing group 16 elements and heteroaromatic rings formed exclusively with six-membered rings and containing one N heteroatom.

[0032] R 1 , R 2 and Ra are preferably aromatic groups having 5 to 17 carbon atoms, more preferably aromatic groups having 6 to 20 carbon atoms, and more preferably aromatic groups having 5 to 15 carbon atoms, and further preferably phenyl groups, biphenylyl groups, naphthyl groups, pyridyl groups, quinolyl groups, and isoquinolyl groups, and particularly preferably phenyl groups, biphenylyl groups, and pyridyl groups.

[0033] Rb represents hydrogen, deuterium, or an alkyl group having 1 to 10 carbon atoms, preferably hydrogen or an alkyl group having 1 to 8 carbon atoms, more preferably hydrogen or an alkyl group having 1 to 4 carbon atoms, more preferably hydrogen or a methyl group, and still more preferably hydrogen. Two or more of Ra and Rb may be different from each other.

[0034] [ka]

[0035] a represents an integer of 0 to 3, preferably an integer of 1 to 3, and more preferably an integer of 1 to 2; b represents an integer of 1 to 4, preferably an integer of 1 to 3, more preferably an integer of 2 to 4, and more preferably an integer of 1 or 2; a+b is 3 or 4; c represents an integer of 1 to 3, preferably 1 or 2, and more preferably 2 or 3;

[0036] Ar 1 , Ar 2 , L, R 1 , R 2 , Ra and Rb may be substituted with an alkyl group having 1 to 10 carbon atoms or a CN group, and these are Ar 1 , L, R 1 , R 2 and the number of carbon atoms of the aromatic groups forming Ra is not included in the number of carbon atoms.

[0037] Ar 1 , Ar 2 , L, R 1 , R 2 Each of Ar, Ra, and Rb is preferably substituted with an alkyl group having 1 to 8 carbon atoms, and more preferably with an alkyl group having 1 to 4 carbon atoms. 1 , Ar 2 , L, R 1 , R 2 , Ra and Rb are preferably substituted with a CN group.

[0038] However, Ar 1 and Ar 2 does not have the following groups. The dotted lines indicate the points of attachment to other groups.

[0039] [ka] The formula (2-A) or (2-B) is preferably any of the following formulas (2-1) to (2-8). In the formula, the dotted line represents the bonding point with L. X 1 ~X 4 represents CH or N, and X 1 ~X 4 Two or more of these cannot be N at the same time. R3 is R 1 and R 2 is synonymous with.

[0040] [ka]

[0041] [X 11 ~X 14 and X 21 ~X 24 About X 11 ~X 14 and X 21 ~X 24 represents C-Ra, C-Rb or N, and X 11 ~X 14 and X 21 ~X 24 Two or more of the following cannot be N at the same time. Also, X 11 ~X 14 Of these, three or more cannot be C-Ra at the same time, and X 21 ~X 24 Two or more of these cannot be C-Ra at the same time.

[0042] [X 1 ~X 4 About X 1 ~X 4 represents CH or N, and X 1 ~X 4 Two or more of the following cannot be N at the same time.

[0043] [R 1 , R 2 and Ra] R 1 , R 2 and Ra represent a monocyclic or condensed ring, or an aromatic group having 5 to 20 carbon atoms which may be linked thereto, and the aromatic group is an aromatic hydrocarbon ring formed by a single ring or a combination of rings listed below, a heteroaromatic ring having a Group 16 element and not containing two or more N atoms, and a heteroaromatic ring formed only by 6-membered rings and containing one N as a heteroatom.

[0044] R 1 , R 2 and Ra are preferably aromatic groups having 5 to 17 carbon atoms, more preferably aromatic groups having 6 to 20 carbon atoms, and more preferably aromatic groups having 5 to 15 carbon atoms, and further preferably phenyl groups, biphenylyl groups, naphthyl groups, pyridyl groups, quinolyl groups, and isoquinolyl groups, and particularly preferably phenyl groups, biphenylyl groups, and pyridyl groups.

[0045] [R b About Rb represents hydrogen, deuterium, or an alkyl group having 1 to 10 carbon atoms, preferably hydrogen or an alkyl group having 1 to 8 carbon atoms, more preferably hydrogen or an alkyl group having 1 to 4 carbon atoms, more preferably hydrogen or a methyl group, and still more preferably hydrogen. Two or more of Ra and Rb may be different from each other.

[0046] [Regarding a, b, and c] a represents an integer of 0 to 3, preferably an integer of 1 to 3, and more preferably an integer of 1 to 2. b represents an integer of 1 to 4, preferably an integer of 1 to 3, more preferably an integer of 2 to 4, and even more preferably an integer of 2 to 3. a+b is 3 or 4; c represents an integer of 1 to 3, preferably 1 or 2, and more preferably 2 or 3. It is preferred that a+b is 3.

[0047] [Other partial structures] Ar 1 , Ar 2 If there are two or more Ls, multiple Ar 1 , Ar 2 and L may be different from each other. 1 , Ar 2 , L, R 1 , R 2 , Ra and Rb may be substituted with an alkyl group having 1 to 10 carbon atoms or a CN group, and these are Ar 1, L, R 1 , R 2 and the number of carbon atoms of the aromatic groups forming Ra is not included in the number of carbon atoms.

[0048] Ar 1 , Ar 2 , L, R 1 , R 2 Each of Ra and Rb is preferably unsubstituted or substituted with an alkyl group having 1 to 8 carbon atoms, more preferably unsubstituted or substituted with an alkyl group having 1 to 4 carbon atoms, and further preferably unsubstituted. Ar in formula (1) 1 and Ar 2 does not have the following groups: The dotted lines indicate the points of attachment to other groups.

[0049] [ka] The above group has two 3-pyridyl groups, which are likely to form intermolecular hydrogen bonds, arranged in a straight line, and thus promotes spontaneous molecular orientation, and has a strong tendency to increase the crystallinity of the compound and inhibit its amorphous nature.

[0050] Specific examples of the pyrimidine compound of the present disclosure will be shown below in relation to preferred embodiments of the present disclosure, but the present disclosure is not limited thereto.

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[0084] The pyrimidine compounds can be used, for example, in organic electronic devices such as organic electroluminescent devices and photoelectric devices.

[0085] <Materials for organic electroluminescence devices> A material for an organic electroluminescent device according to one embodiment of the present disclosure contains a pyrimidine compound. The pyrimidine compound can be used, for example, as an electron transport material for an organic electroluminescent device.

[0086] The structural reason why the pyrimidine compound according to one embodiment of the present disclosure exhibits high current efficiency as, for example, an electron transport material for an organic electroluminescent device is presumed to be as follows.

[0087] <Structural reasons for high current efficiency> Triazine rings, which are incorporated into materials that are widely used for small mobile applications, have three highly electronegative nitrogen atoms in the ring structure, which gives the ring itself a large electron affinity and provides high electron injection and transport capabilities from the cathode.

[0088] However, the high electron affinity of the triazine ring inhibits electron injection into the commonly used light-emitting layer or hole-blocking layer. On the other hand, pyrimidine rings contain multiple nitrogen atoms like triazine, but reducing the number of nitrogen atoms reduces the electron affinity and promotes electron injection into the light-emitting layer or hole-blocking layer. This promoted electron injection can provide high current efficiency.

[0089] On the other hand, unlike the triazine ring, the pyrimidine ring itself has a large dipole moment. It is known that when organic molecules in an organic thin film have a dipole moment, the organic molecules spontaneously orient themselves to form a film with an order similar to a crystal structure. It is generally known that a film with high crystallinity generates defects in the film, which impedes charge transport, and therefore a high degree of amorphousness is required for organic films used in organic electroluminescent devices.

[0090] In addition, the spontaneous orientation of organic molecules increases the sublimation temperature, which accelerates thermal decomposition during the production of organic electroluminescent devices and ultimately affects the deterioration of the durability of the organic electroluminescent devices due to the inclusion of decomposed materials.

[0091] That is, although a compound having a pyrimidine ring can promote the electron injection into the light-emitting layer or the hole-blocking layer, there is a problem in that the electron transport in the film is suppressed.

[0092] In contrast, a compound according to one embodiment of the present disclosure is represented by the general formula (1):2 Since it has a high steric hindrance, it is possible to suppress spontaneous molecular orientation and have a high amorphous property. In addition, it contributes to lowering the sublimation temperature, so it is possible to contribute to suppressing thermal decomposition of the material and suppressing deterioration of the durability of the organic electroluminescent device.

[0093] [ka]

[0094] <Organic electroluminescent device> Hereinafter, an organic electroluminescent device including a pyrimidine compound according to one embodiment of the present disclosure (hereinafter, may be simply referred to as an organic electroluminescent device) will be described.

[0095] The organic electroluminescent device according to one embodiment of the present disclosure contains a pyrimidine compound. The configuration of the organic electroluminescent device is not particularly limited, but examples thereof include the following configurations (i) to (vi). (i): Anode / Emitting layer / Cathode (ii): anode / hole transport layer / light emitting layer / cathode (iii): anode / light-emitting layer / electron transport layer / cathode (iv): anode / hole transport layer / light emitting layer / electron transport layer / cathode (v): anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (vi): Anode / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode

[0096] The pyrimidine compound may be contained in any of the above layers, but is preferably contained in one or more layers selected from the group consisting of the light-emitting layer and the layer between the light-emitting layer and the cathode, in terms of excellent light-emitting properties of the organic electroluminescent device. Therefore, in the case of the configurations shown in (i) to (vi) above, the pyrimidine compound is preferably contained in one or more layers selected from the group consisting of the light-emitting layer, the electron transport layer, and the electron injection layer.

[0097] Hereinafter, the organic electroluminescent device according to one embodiment of the present disclosure will be described in more detail with reference to FIG. 1, taking the above configuration (v) as an example.

[0098] 1 has a so-called bottom emission type element configuration, the organic electroluminescent element according to one embodiment of the present disclosure is not limited to the bottom emission type element configuration. That is, the organic electroluminescent element according to one embodiment of the present disclosure may have another known element configuration, such as a top emission type.

[0099] FIG. 1 is a schematic cross-sectional view showing an example of a layered structure of an organic electroluminescent device according to one embodiment of the present disclosure.

[0100] The organic electroluminescent device 100 includes a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, an emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode 8, in this order. However, some of these layers may be omitted, or other layers may be added. For example, a hole blocking layer may be provided between the emitting layer 5 and the electron transport layer 6, or the hole injection layer 3 may be omitted and the hole transport layer 4 may be provided directly on the anode 2.

[0101] Alternatively, a single layer having the functions of the multiple layers, such as an electron injection / transport layer having both the functions of the electron injection layer and the electron transport layer in a single layer, may be provided instead of the multiple layers. Furthermore, for example, the single-layer hole transport layer 4 and the single-layer electron transport layer 6 in the above example may each be made up of multiple layers.

[0102] <Layer Containing Pyrimidine Compound> 1, the organic electroluminescent device 100 contains the pyrimidine compound in one or more layers selected from the group consisting of the light-emitting layer 5, the electron transport layer 6, and the electron injection layer 7. In particular, it is preferable that the electron transport layer 6 contains the pyrimidine compound. The pyrimidine compound may be contained in multiple layers of the organic electroluminescent device.

[0103] In the following, an organic electroluminescent device 100 in which the electron transport layer 6 contains a pyrimidine compound will be described.

[0104] [Substrate 1] There is no particular limitation on the substrate 1, and any substrate that can be used for a normal organic electroluminescent device can be used, such as a glass plate, a quartz plate, or a plastic plate.

[0105] [Anode 2] An anode 2 is provided on the substrate 1 (on the hole injection layer 3 side). The anode material may be a compound that can be used in a normal organic electroluminescent device. For example, metals with a large work function (e.g., 4 eV or more), alloys, electrically conductive compounds, and mixtures thereof may be used. Specific examples of the anode material include metals such as Au; and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO.

[0106] [Hole injection layer 3, hole transport layer 4] Between the anode 2 and a light-emitting layer 5 described below, a hole injection layer 3 and a hole transport layer 4 are provided in this order from the anode 2 side.

[0107] The material for the hole injection layer and the hole transport layer may be one having at least one of hole injection property, hole transport property, and electron barrier property. The material for the hole injection layer and the hole transport layer may be either an organic substance or an inorganic substance, and a compound that can be used for a general organic electroluminescence device may be used.

[0108] The hole injection layer and the hole transport layer may have a single structure made of one or more materials, or may have a laminate structure made of multiple layers of the same or different compositions.

[0109] The hole transport layer 4 may have a laminated structure of two or more layers, and is provided in the following order from the anode 2 side: a first hole transport layer 41 and a second hole transport layer 42. This second hole transport layer 42 can be used as an electron blocking layer in the above configuration (vi).

[0110] [Light-emitting layer 5] The light-emitting layer 5 is provided between the hole transport layer 4 and the electron transport layer 6 described below. The material for the light-emitting layer may be any light-emitting material that can be used in ordinary organic electroluminescent devices, such as phosphorescent materials, fluorescent materials, and thermally activated delayed fluorescent materials. The light-emitting layer may consist of a single small molecule or single polymeric material, but more commonly consists of a host material doped with a guest compound. Emission comes primarily from the dopant and can be of any color.

[0111] In addition, the light-emitting material is not limited to being contained only in the light-emitting layer. For example, the light-emitting material may be contained in a layer adjacent to the light-emitting layer (hole transport layer 4 or electron transport layer 6). This can further increase the light-emitting efficiency of the organic electroluminescent device.

[0112] The light-emitting layer may have a single layer structure made of one or more materials, or may have a laminate structure made of multiple layers of the same composition or different compositions.

[0113] [Electron transport layer 6] An electron transport layer 6 is provided between the light emitting layer 5 and an electron injection layer 7 described below.

[0114] The electron transport layer preferably contains a pyrimidine compound. The electron transport layer may further contain, in addition to the pyrimidine compound, one or more types selected from conventionally known electron transport materials.

[0115] When the pyrimidine compound is not contained in the electron transport layer but is contained in another layer, one or more types selected from conventionally known electron transport materials can be used as the electron transport material constituting the electron transport layer.

[0116] Examples of conventionally known electron transporting materials include alkali metal complexes, alkaline earth metal complexes, and earth metal complexes. Examples of alkali metal complexes, alkaline earth metal complexes, and earth metal complexes include 8-hydroxyquinolinato lithium (Liq), bis(8-hydroxyquinolinato) zinc, bis(8-hydroxyquinolinato) copper, bis(8-hydroxyquinolinato) manganese, tris(8-hydroxyquinolinato) aluminum, tris(2-methyl-8-hydroxyquinolinato) aluminum, and tris(8-hydroxyquinolinato). Examples of such compounds include gallium, bis(10-hydroxybenzo[h]quinolinato)beryllium, bis(10-hydroxybenzo[h]quinolinato)zinc, bis(2-methyl-8-quinolinato)chlorogallium, bis(2-methyl-8-quinolinato)(o-cresolate)gallium, bis(2-methyl-8-quinolinato)-1-naphtholate aluminum, and bis(2-methyl-8-quinolinato)-2-naphtholate gallium.

[0117] The electron transport layer may have a single layer structure made of one or more materials, or may have a laminate structure made of multiple layers of the same composition or different compositions.

[0118] In the organic electroluminescent device according to this embodiment, an electron injection layer may be provided for the purpose of improving the electron injection property and improving the device characteristics (for example, luminous efficiency, low-voltage driving, or high durability).

[0119] The electron transport layer 6 may have a laminated structure of two or more layers, and is provided in the following order from the light-emitting layer 5 side: a first electron transport layer 61 and a second electron transport layer 62. This first electron transport layer 61 can be used as a hole blocking layer in the above configuration (vi).

[0120] The pyrimidine compound according to one embodiment of the present disclosure can be used in both or either of the first electron transport layer and the second electron transport layer.

[0121] [Electron injection layer 7] Between the electron transport layer 6 and a cathode 8 described below, an electron injection layer 7 is provided. The material for the electron injection layer may be a compound that can be used in a normal organic electroluminescent device, such as fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylene tetracarboxylic acid, fluorenylidene methane, anthraquinodimethane, anthrone, or 8-hydroxyquinolinato lithium (Liq).

[0122] Examples of materials for the electron injection layer include inorganic compounds such as various oxides, fluorides, nitrides, and oxynitrides, such as SiO, AlO, SiN, SiON, AlON, GeO, LiO, LiON, TiO, TiON, TaO, TaON, TaN, and LiF, as well as metals, such as Li, Cs, and Yb, and compositions of combinations of two or more of these metals.

[0123] [Cathode 8] A cathode 8 is provided on the electron injection layer 7 . The cathode material can be a compound that can be used in a normal organic electroluminescent device. For example, a metal with a small work function (hereinafter also referred to as an electron injection metal), an alloy, an electrically conductive compound, and a mixture thereof can be used. Here, the metal with a small work function is, for example, a metal with a work function of 4 eV or less.

[0124] As the material for the cathode, a mixture of an electron injecting metal and a second metal which has a larger and more stable work function than the electron injecting metal, such as a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al2O3) mixture, or a lithium / aluminum mixture, is preferred.

[0125] [How each layer is formed] Each layer except for the electrodes (anode, cathode) described above can be formed into a thin film by a known method such as vacuum deposition, spin coating, casting, LB (Langmuir-Blodgett) method, etc. The material of each layer may be used alone or, if necessary, together with a material such as a binder resin or a solvent.

[0126] The thickness of each layer thus formed is not particularly limited and can be appropriately selected depending on the situation, but is usually in the range of 5 nm to 5 μm, and more preferably in the range of 5 nm to 500 nm.

[0127] The anode and cathode can be formed by forming a thin film of an electrode material by a method such as vapor deposition, sputtering, etc. A pattern may be formed through a mask having a desired shape during vapor deposition or sputtering, or a pattern having a desired shape may be formed by photolithography after forming a thin film by vapor deposition, sputtering, etc.

[0128] The film thickness of the anode and cathode is preferably 1 μm or less, and more preferably 10 nm or more and 200 nm or less.

[0129] In addition, when forming a layer containing a pyrimidine compound, the above-mentioned conventionally known electron transporting material may be used in combination. Thus, for example, the pyrimidine compound and the conventionally known electron transporting material may be co-deposited, or a layer of the conventionally known electron transporting material may be laminated on the layer of the pyrimidine compound.

[0130] The organic electroluminescent device may be used as a type of lamp for illumination or exposure light source, or as a projection device that projects an image onto a screen or the like, or as a display device (display) that directly displays still images or moving images.

[0131] When an organic electroluminescent element is used as a display device for playing moving images, the driving method may be a simple matrix (passive matrix) method or an active matrix method. In addition, by using two or more kinds of organic electroluminescent elements having different luminescent colors, a full-color display device can be produced.

[0132] The pyrimidine compound according to one embodiment of the present disclosure can provide an organic electroluminescent device having significantly superior current efficiency and luminous efficiency when used in an electron transport layer, as compared with known pyrimidine compounds.

[0133] The pyrimidine compound according to one embodiment of the present disclosure can be used as an electron transport layer in an organic electroluminescent device to provide a pyrimidine compound capable of achieving high current efficiency, high luminous efficiency, and long life of the device. Furthermore, an organic electroluminescent device that can achieve high current efficiency, high luminous efficiency, and long life using the pyrimidine compound according to one embodiment of the present disclosure can be provided. EXAMPLES

[0134] The present disclosure will be described in more detail below based on examples, but the present disclosure should not be construed as being limited to these examples.

[0135] 1 H-NMR spectra were measured using a Gemini200 (Varian) or a Bruker ASCEND 400 (400 MHz; BRUKER). The light-emitting characteristics of the organic electroluminescent device were evaluated by applying a direct current to the fabricated device at room temperature using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse Corporation).

[0136] Synthesis Example 1 (Synthesis of E1)

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] 4-Chlorobenzamidine hydrochloride (5.00g, 26.2mmol) and 1,3-(4-biphenylyl)propen-3-one (19.8g, 55.0mmol) were suspended in acetic acid (90.8mL), to which 2M potassium hydroxide-ethanol solution (40mL) was added dropwise, and the mixture was refluxed for 20 hours. After cooling, water was added to the reaction mixture, and the solid was filtered out, and the filtered product was washed with water. The filtered product was recrystallized from toluene (130mL) to obtain the desired 2-(4-chlorophenyl)-4,6-bis(4-biphenylyl)pyrimidine (M1). (Complete 8.0g, yield 62%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.68(d,J=8.7Hz,2H),8.36(d,J=8.48,4H).8.08(s,1H ),7.80(d,J=8.5Hz,4H),7.69-7.71(m,4H),7.49-7.54(m,6H),7.42(t,J=7.3Hz,2H).

[0141] Under an argon atmosphere, 2-(4-chlorophenyl)-4,6-bis(4-biphenylyl)pyrimidine (5.00 g, 10.1 mmol), bis(pinacolato)diboron (2.82 g, 11.1 mmol), potassium acetate (2.97 g, 30.3 mmol), palladium acetate (22.4 mg, 0.10 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 95 mg, 0.20 mmol) were suspended in THF (51 mL) and refluxed for 15 hours. The reaction mixture was filtered and the filtrate was concentrated. The concentrated filtrate was added to methanol to precipitate a solid, which was then filtered to obtain the target compound, 4,6-bis(4-biphenylyl)-2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-pyrimidine (final value 5.54 g, yield 94%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.74(d,J=8.3Hz,2H),8.40(d,J=8.5Hz,4H),8.11(s,1H),8.00(d,J=8.3H z,2H),7.82(d,J=8.5Hz,4H),7.70-7.72(m,4H),7.49-7.52(m,4H),7.42((t,J=7.4Hz,2H),1.40(s,12H).

[0142] Under an argon atmosphere, 4,6-bis(4-biphenylyl)-2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-pyrimidine (2.50 g, 4.26 mmol), 2,6-diphenyl-3-chloropyridine (1.25 g, 4.69 mmol), 2M potassium phosphate aqueous solution (4.3 mL), palladium acetate (19 mg, 0.085 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 81 mg, 0.17 mmol) were suspended in THF (43 mL) and refluxed for 15 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 2-[4-(2,6-diphenylpyridyl-3-yl)phenyl]-4,6-bis(4-biphenylyl)pyrimidine (E1) (yield: 3.18 g, 90%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.71(dd,J=8.5Hz,2H),8.39(d,J=8.6Hz,4H),8.17-8.19(m,2H),8.10(s,1H),7.90(d,J=8.0Hz,1H),7.9 3(d,J=8.0Hz,1H),7.80(d,J=8.5Hz,4H),7.69-7.71(m,4H),7.55-7.58(m,2H),7.49-7.53(m,6H),7.39-7.46(m,5H),7.27-7.30(m,3H).

[0143] Synthesis Example 2 (Synthesis of E2)

[0144] [ka]

[0145] Under an argon atmosphere, 4,6-bis(4-biphenylyl)-2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-pyrimidine (3.35 g, 5.71 mmol), m-terphenyl-4-trifluoromethanesulfonate (2.38 g, 6.28 mmol), 2M potassium phosphate aqueous solution (8.6 mL), and tetrakis(triphenylphosphine)palladium (270 mg, 0.23 mmol) were suspended in THF (54 mL) and refluxed for 72 hours. After cooling, water was added to the reaction mixture, and the solid was filtered and washed with water and methanol to obtain 2-(2'-phenyl-1,1':4',1''-terphenyl-4-yl)-4,6-bis(4-biphenylyl)pyrimidine (E2) (yield 3.14 g, 90%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.65(d,J=8.5Hz,2H),8.39(d,J=8.5Hz,4H),8.09(s,1H),7,80(d,J=8.5 Hz,4H),7.72-7.69(m,8H),7.63(d,J=8.6Hz,1H),7.52-47(m,6H),7.43-7.37(m,5H),7.30-7.23(m,5H).

[0146] Synthesis Example 3 (Synthesis of E3)

[0147] [ka]

[0148] Under an argon atmosphere, 4,6-bis(4-biphenylyl)-2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-pyrimidine (3.00 g, 5.11 mmol), 5,6-diphenyl-3-chloropyridine (1.63 g, 6.14 mmol), 2M potassium phosphate aqueous solution (7.7 mL), palladium acetate (11 mg, 0.05 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 49 mg, 0.10 mmol) were suspended in THF (51 mL) and refluxed for 15 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 2-[4-(2,6-diphenylpyridyl-3-yl)phenyl]-4,6-bis(4-biphenylyl)pyrimidine (E3) (yield: 3.30 g, 94%). 1 H-NMR(400MHz,CDCl3)δ(ppm):9.05(d,J=2.3Hz,1H), 8.89(d,J=8.4Hz,2H),8.42(d,J=8.3Hz,4H),8.13(s,1H),8.04(d,J=2.2Hz,1H),7.88(d,J=8.4Hz,2H) ,7.82(d,J=8.4Hz,4H),7.70-7.72(m,4H),7.51(t,J=7.3Hz,4H),7.40-7.45(m,4H),7.27-7.34(m,8H).

[0149] Synthesis Example 4 (Synthesis of E4)

[0150] [ka]

[0151] Under an argon atmosphere, 2,4-bis(4-biphenylyl)-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-pyrimidine (3.00 g, 5.11 mmol), 2,6-diphenyl-3-chloropyridine (1.49 g, 5.63 mmol), 2M potassium phosphate aqueous solution (7.7 mL), palladium acetate (23 mg, 0.10 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 98 mg, 0.20 mmol) were suspended in THF (51 mL) and refluxed for 15 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 4-[4-(2,6-diphenylpyridyl-3-yl)phenyl]-2,6-bis(4-biphenylyl)pyrimidine (E4) (yield: 3.18 g, 90%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.81(d,J=8.5Hz,2H),8.39(d,J=8.5Hz,2H),8.28(d,J=8.4Hz,2H),8.17-8.19(m,2H),8.06(s,1H),7.88(d, J=8.0Hz,1H),7.83(d,J=8.0Hz,1H),7.81(d,J=6.5Hz,2H),7.78(d,J=6.5Hz,2H),7.68-7.73(m,4H),7.38-7.57(m,13H),7.29-7.32(m,3H).

[0152] Synthesis Example 5 (Synthesis of E5)

[0153] [ka] Under an argon atmosphere, 4,6-bis(4-biphenylyl)-2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-pyrimidine (11.6 g, 19.7 mmol), o-terphenyl-3-trifluoromethanesulfonate (8.20 g, 21.7 mmol), 2M potassium phosphate aqueous solution (30.0 mL), and tetrakis(triphenylphosphine)palladium (455 mg, 0.39 mmol) were suspended in THF (197 mL) and refluxed for 118 hours. After cooling, water was added to the reaction mixture, and the solid was filtered and washed with water and methanol to obtain 2-(3'-phenyl-1,1':2',1''-terphenyl-4-yl)-4,6-bis(4-biphenylyl)pyrimidine (E5) (yield 12.8 g, 94%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.58(d,J=8.5Hz,2H),8.36(d,J=8.5Hz,4H),8.06(s,1H),7.78(d,J=8.5Hz,4H),7.69(d,J=7.1Hz,4H),7. 47-7.54(m,7H),7.41(t,J=7.3Hz,2H),7.29(d,J=8.5Hz,2H),7.15-7.18(m,3H),7.09-7.12(m,2H),6.99-7.01(m,3H),6.91-6.93(m,2H).

[0154] Synthesis Example 6 (Synthesis of E6)

[0155] [ka] Under an argon atmosphere, 4,6-bis(4-biphenylyl)-2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-pyrimidine (3.00 g, 5.10 mmol), 4'-phenyl-1,1':3',1''-terphenyl-6-trifluoromethanesulfonate (3.54 g, 6.14 mmol), 2M potassium phosphate aqueous solution (8.0 mL), and tetrakis(triphenylphosphine)palladium (177 mg, 0.15 mmol) were suspended in THF (102 mL) and refluxed for 17 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 2-(4',5'-diphenyl-1,1':2',1''-terphenyl-4-yl)-4,6-bis(4-biphenylyl)pyrimidine (E6) (yield: 3.45 g, 88%). 1 H-NMR(CDCl3)δ(ppm):8.73(d,J=8.4Hz,2H),8.59(d,J=9.2Hz,4H),8.47(s,1H),7.89(d,J=8. 4Hz,4H),7.80-7.77(m,4H),7.66(s,1H),7.59(s,1H),7.52-7.39(m,8H),7.37-7.21(m,15H).

[0156] Synthesis Example-7 (Synthesis of E7)

[0157] [ka] Under an argon atmosphere, 4-(4-biphenylyl)-6-phenyl-2-(4-chlorophenyl)-pyrimidine (6.50 g, 15.5 mmol), 3-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-2,6-diphenylpyridine (8.07 g, 18.6 mmol), 2M potassium phosphate aqueous solution (23.3 mL), palladium acetate (35 mg, 0.16 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 148 mg, 0.31 mmol) were suspended in THF (155 mL) and refluxed for 15 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 2-[4'-(2,6-diphenylpyridin-3-yl)-biphenyl-4-yl]-4-(4-biphenylyl)-6-phenylpyrimidine (E7) (yield: 4.10 g, 38%). 1 H-NMR(CDCl3)δ(ppm):8.75(d,J=8.4Hz,2H),8.34(d,J=8.8Hz,2H),8.26(dd,J=8.4Hz ,1.6Hz,2H),8.11(d,J=7.6Hz,2H),8.01(s,1H),7.81-7.73(m,6H),7.62(dd,J=15.6H z,7.2Hz,4H),7.55-7.50(m,3H),7.49(d,J=2.4Hz,1H),7.44(dd,J=7.6Hz,7.6Hz,4H) ,7.36(dd,J=15.2Hz,7.6Hz,4H),7.29(d,J=8.4Hz,2H),7.24(dd,J=3.6Hz,3.6Hz,4H).

[0158] Synthesis Example-8 (Synthesis of E8)

[0159] [ka] Under an argon atmosphere, 4-(4-biphenylyl)-6-phenyl-2-(4-chlorophenyl)-pyrimidine (3.00 g, 7.16 mmol), 3-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-2,6-diphenylpyridine (3.60 g, 8.59 mmol), 2M potassium phosphate aqueous solution (10.7 mL), palladium acetate (16 mg, 0.07 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 68 mg, 0.14 mmol) were suspended in THF (72 mL) and refluxed for 41 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 2-[3'-(2,6-diphenylpyridin-3-yl)-biphenyl-4-yl]-4-(4-biphenylyl)-6-phenylpyrimidine (E8) (yield: 4.19 g, 85%). 1 H-NMR(CDCl3)δ(ppm):8.78(d,J=8.8Hz,2H),8.42(d,J=8.8Hz,2H),8.35(dd,J=8.0Hz,2.0Hz,2H),8 .20(dd,J=8.4Hz,1.2Hz,2H),8.10(s,1H),7.93(d,J=7.6Hz,1H),7.85(dd,J=8.8Hz,6.4Hz,3H),7.7 3(brdd,J=8.4Hz,1.6Hz,2H),7.65-7.62(m,2H),7.61(dd,J=2.0Hz,2.0Hz,2H),7.59(dd,J=2.0Hz,2 .0Hz,2H),7.58-7.53(m,6H),7.51(brdd,J=2.0Hz,2.0Hz,1H),7.48-7.42(m,3H),7.38-7.31(m,4H).

[0160] Synthesis Example-9 (Synthesis of E9)

[0161] [ka] Under an argon atmosphere, 6-(4-biphenylyl)-2-phenyl-4-(4-chlorophenyl)-pyrimidine (15.0 g, 32.4 mmol), 3-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-2,6-diphenylpyridine (16.3 g, 38.9 mmol), 2M potassium phosphate aqueous solution (48.6 mL), palladium acetate (73 mg, 0.32 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 309 mg, 0.65 mmol) were suspended in THF (324 mL) and refluxed for 3 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 4-[3'-(2,6-diphenylpyridin-3-yl)-biphenyl-4-yl]-6-(4-biphenylyl)-2-phenylpyrimidine (E9) (yield: 18.6 g, 83%). 1 H-NMR(CDCl3)δ(ppm):8.78(dd,J=8.4Hz,2.0Hz,2H),8.42(d,J=8.0Hz,2H),8.36(d,J=8.8Hz,2H),8.20(dd,J=7.6Hz,1.6Hz,2H),8.1 1(s,1H),7.93(d,J=8.4Hz,1H),7.87-7.82(m,3H),7.73(brd,J=6.8Hz,2H),7.64-7.51(m,13H),7.50-7.42(m,3H),7.38-7.34(m,4H).

[0162] Synthesis Example 10 (Synthesis of E10)

[0163] [ka] Under an argon atmosphere, 2-[4'-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-biphenyl-4-yl]-4-(4-biphenyl)-6-phenylpyrimidine (7.20 g, 12.3 mmol), o-terphenyl-3-trifluoromethanesulfonate (5.57 g, 14.7 mmol), 2M potassium phosphate aqueous solution (18.0 mL), and tetrakis(triphenylphosphine)palladium (426 mg, 0.37 mmol) were suspended in THF (246 mL) and refluxed for 48 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 2-(3''-phenyl-1,1':4',1'':2'',1''-quaterphenyl-4-yl)-4-(4-biphenylyl)-6-phenylpyrimidine (E5) (yield: 8.46 g, 70%). 1 H-NMR(CDCl3)δ(ppm):8.81(d,J=8.4Hz,2H),8.42(d,J=8.4Hz,2H),8.35(dd,J=8.0Hz,2.4H z,2H),8.09(s,1H),7.83(d,J=8.4Hz,2H),7.78(d,J=8.4Hz,2H),7.74-7.72(m,2H),7.64-7 .56(m,3H),7.55-7.53(m,4H),7.50(d,J=4.4Hz,1H),7.49-7.41(m,2H),7.23(d,J=8.0Hz,2 H),7.20-7.17(m,4H),7.13-7.10(m,2H),7.07-7.01(m,3H),6.93(dd,J=5.2Hz,1.6Hz,2H).

[0164] Synthesis Example 11 (Synthesis of E11)

[0165] [ka] Under an argon atmosphere, 2-(4-chlorophenyl)-4-[4-(9-phenanthryl)phenyl]-6-phenylpyrimidine (5.00 g, 9.63 mmol), 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)biphenyl (3.05 g, 11.56 mmol), 2M potassium phosphate aqueous solution (14 mL), palladium acetate (43 mg, 0.19 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 184 mg, 0.39 mmol) were suspended in THF (96 mL) and refluxed for 21 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 4-[4-(9-phenanthryl)phenyl]-2-(1,1',2',1''-terphenyl-4-yl)-6-phenylpyrimidine (E11) (yield: 6.11 g, 99%). 1 H-NMR(CDCl3)δ(ppm):8.81(d,J=8.4Hz,1H),8.76(d,J=8.4Hz,1H),8.64(d,J=8. 0Hz,2H),8.43(d,J=8.0Hz,2H),8.32(brdd,J=8.0Hz,2.4Hz,2H),8.11(s,1H),7.9 6(brdd,J=13.6Hz,8.4Hz,2H),7.76-7.69(m,4H),7.65(brdd,J=7.6Hz,7.6Hz,1H ),7.61-7.52(m,6H),7.49-7.45(m,3H),7.35(d,J=8.8Hz,2H),7.25-7.20(m,5H).

[0166] Synthesis Example 12 (Synthesis of E12)

[0167] [ka] Under an argon atmosphere, 6-phenyl-2,4-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]pyrimidine (2.00g, 3.60mmol), 2-(1-naphthyl)-3-chloropyridine (1.88g, 7.85mmol), 2M potassium phosphate aqueous solution (10.7mL), palladium acetate (32mg, 0.14mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 136mg, 0.29mmol) were suspended in THF (36mL) and refluxed for 17 hours. After cooling, water was added to the reaction mixture and the solid was filtered and washed with water and methanol. The obtained solid was recrystallized from toluene to obtain 2,4-bis[2-(1-naphthyl)pyridin-3-yl]-6-phenylpyrimidine (E12) (yield: 1.32 g, 60%). 1 H-NMR(CDCl3)δ(ppm):8.80(ddd,J=9.6Hz,9.6Hz,1.6Hz,2H),8.37(d,J=8.8Hz,2H),8.13(brdd, J=6.0Hz,2.0Hz,2H),7.95-7.91(m,4H),7.85-7.73(m,7H),7.51-7.38(m,9H),7.34-7.20(m,8H).

[0168] Synthesis Example 13 (Synthesis of E13)

[0169] [ka] Under an argon atmosphere, 2-phenyl-4,6-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]pyrimidine (13.0g, 23.2mmol), 2-(1-naphthyl)-3-chloropyridine (12.2g, 51.0mmol), 2M potassium phosphate aqueous solution (35.0mL), palladium acetate (208mg, 0.93mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 885mg, 1.86mmol) were suspended in THF (232mL) and refluxed for 17 hours. After cooling, water was added to the reaction mixture, and the solid was filtered and washed with water and methanol. The obtained solid was recrystallized from toluene to obtain 4,6-bis[2-(1-naphthyl)pyridin-3-yl]-2-phenylpyrimidine (E12) (yield: 5.14 g, 31%). 1 H-NMR(CDCl3)δ(ppm):8.81(dd,J=4.8Hz,1.2Hz,2H),8.57(dd,J=6.8Hz,3.2Hz,2H),7.95(d,J=8 .0Hz,5H),7.83(dd,J=6.4Hz,1.2Hz,2H),7.82(brd,J=2.4Hz,1H),7.78(d,J=7.2Hz,2H),7.74(m, 2H),7.69(s,1H),7.51-7.49(m,2H),7.47(dd,J=5.6Hz,2.8Hz,4H),7.44(d,J=1.6Hz,1H),7.42( dd,J=2.0Hz,2.0Hz,2H),7.41(d,J=2.0Hz,1H),7.32(dd,J=8.0Hz,8.0Hz,2H),7.24-7.21(m,6H).

[0170] Synthesis Example 14 (Synthesis of E14)

[0171] [ka] Under an argon atmosphere, 2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-4-(4-biphenylyl)-6-phenylpyrimidine (22.0 g, 43.1 mmol), 3-(4-chlorophenyl)-2-phenylpyridine (13.7 g, 51.7 mmol), 2M potassium phosphate aqueous solution (65 mL), palladium acetate (194 mg, 0.86 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 822 mg, 1.72 mmol) were suspended in THF (216 mL) and refluxed for 15 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 2-[4'-(2-phenylpyridin-3-yl)-biphenyl-4-yl]-4-(4-biphenylyl)-6-phenylpyrimidine (E14) (yield: 10.6 g, 40%). 1 H-NMR(CDCl3)δ(ppm):8.81(d,J=8.4Hz,2H),8.72(dd,J=4.8Hz,2.0Hz,1H),8.40(d ,J=8.0Hz,2H),8.33(dd,J=8.0Hz,1.6Hz,2H),8.07(s,1H),7.82-7.78(m,5H),7.71( brdd,J=7.2Hz,1.2Hz,2H),7.65(d,J=8.4Hz,2H),7.62-7.56(m,3H),7.51(dd,J=7.2 Hz,7.2Hz,2H),7.45-7.41(m,3H),7.37(dd,J=8.0Hz,5.2Hz,1H),7.32-7.28(m,5H).

[0172] Synthesis Example 15 (Synthesis of E15)

[0173] [ka] Under an argon atmosphere, 2-(4'-chlorobiphenyl-4-yl)-4-(biphenyl-4-yl)-6-phenylpyrimidine (2.40 g, 4.84 mmol), 2-phenylpyridine (1.50 g, 9.68 mmol), 4-(trifluoromethyl)benzoic acid (276 mg, 1.45 mmol), potassium carbonate (1.34 g, 9.68 mmol) and dichloro(p-cymene)ruthenium dimer (89 mg, 0.15 mmol) were suspended in toluene (48 mL) and refluxed for 23 hours. After cooling, the solvent was removed by distillation, and the residue was washed with water, ethanol, and hexane to obtain 2-[2″-(2-pyridyl)-1,1′:4′,1″-terphenyl-4-yl]-4-(biphenyl-4-yl)-6-phenylpyrimidine (E15) (yield: 1.03 g, 35%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.80(d,J=8.3Hz,2H),8.67(dd,J=4.9,1.0Hz,1H) ,8.40(d,J=8.5Hz,2H),8.33(dd,J=7.9,2.0Hz,2H),8.07(s,1H),7.81(d,J=8.6Hz ,2H),7.78(d,J=8.6Hz,2H),7.70-7.74(m,3H),7.56-7.62(m,5H),7.39-7.53(m,7 H)7.29(d,J=8.4Hz,2H),7.14(ddd,J=7.5,4.9,1.3Hz,1H),7.01(d,J=7.8Hz,1H).

[0174] Synthesis Example 16 (Synthesis of E16)

[0175] [ka] Under an argon atmosphere, 2-(4-chlorophenyl)-4-(biphenyl-4-yl)-6-phenylpyrimidine (2.00 g, 4.77 mmol), 4-(2-pyridyl)biphenyl (2.21 g, 9.55 mmol), 4-(trifluoromethyl)benzoic acid (272 mg, 1,43 mmol), potassium carbonate (1.32 g, 9.55 mmol) and dichloro(p-cymene)ruthenium dimer (88 mg, 0.14 mmol) were suspended in toluene (48 mL) and refluxed for 23 hours. After cooling, the solvent was distilled off and the residue was washed with water, ethanol and hexane to obtain 2-[2'-(2-pyridyl)-1,1':5',1"-terphenyl-4-yl]-4-(biphenyl-4-yl)-6-phenylpyrimidine (E16) (yield 2.63 g, 90%). 1 H-NMR(400MHz, CDCl3)δ(ppm):8.7

[0176] Synthesis Example 17 (Synthesis of E17)

[0177] [ka] Under an argon atmosphere, 2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-4,6-bis(4-biphenylyl)pyrimidine (3.00 g, 5.11 mmol), 3-(4-chlorophenyl)-2-phenylpyridine (1.63 g, 6.14 mmol), 2M potassium phosphate aqueous solution (8 mL), palladium acetate (11 mg, 0.05 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 49 mg, 0.10 mmol) were suspended in THF (26 mL) and refluxed for 15 hours. After cooling, water was added to the reaction mixture, and the solid was filtered off and washed with water and methanol to obtain 2-[4'-(2-phenylpyridin-3-yl)-biphenyl-4-yl]-4,6-bis(4-biphenylyl)pyrimidine (E17) (yield: 3.00 g, 85%). 1H-NMR(CDCl3)δ(ppm):8.83(d,J=8.8Hz,2H),8.73(dd,J=4.8Hz,1.6Hz,1H),8.41(d,J=8.8Hz,4H),8.11(s,1H),7.83-7.79 (m,7H),7.72-7.69(m,4H),7.65(brd,J=13.2Hz,2H),7.51(dd,J=7.2Hz,7.2Hz,4H),7.45-7.36(m,5H),7.33-7.28(m,5H).

[0178] Synthesis Example-18 (Synthesis of E18)

[0179] [ka] Under an argon atmosphere, 4-[4'-chloro-[(1,1'-biphenyl)-4-yl]]-2,6-diphenyl-pyrimidine (4.70 g, 11.2 mmol), 3-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-2,6-diphenylpyridine (5.65 g, 13.5 mmol), palladium acetate (50.9 mg, 0.22 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.32 g, 0.45 mmol) were suspended in THF (56 mL). 2M potassium phosphate aqueous solution (17 mL, 34 mmol) was added to this suspension and stirred at 70 ° C for 60 hours. After cooling to room temperature, water and methanol were added and the precipitated solid was collected by filtration. The residue was suspended in toluene (300 mL) and heated to 110°C, and activated carbon was added and stirred, followed by celite filtration. The filtrate was concentrated and purified by recrystallization from toluene to obtain 4-[3' '-(2,6-diphenylpyridin-3-yl)-(1,1':4',1' '-terphenyl)-4-yl]-2,6-diphenyl-pyrimidine (E18) (6.6 g, yield 85%). 1H-NMR(CDCl3)δ(ppm):8.75(dd,J=8.0Hz,2.4Hz,2H),8.40(d,J=8.8Hz,2H),8.32(dd,J=8.4Hz,3.2Hz,2H),8.18(brdd,J=8.8Hz,1.6Hz,2H),8.07(s,1H), 7.90-7.82(m,4H),7.73(d,J=8.0Hz,2H),7.61-7.53(m,10H),7.51(d,J=2.0 Hz,2H),7.49(dd,J=1.6Hz,1.6Hz,2H),7.46-7.40(m,2H),7.35-7.27(m,4H).

[0180] Synthesis Example-19 (Synthesis of E19)

[0181] [ka] Under an argon atmosphere, 4-[(1,1'-biphenyl)-4-yl]-6-phenyl-2-[4'-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-(1,1':2',1''-terphenyl)-4-yl]pyrimidine (1.57g, 2.08mmol), 4-bromobenzonitrile (0.518g, 2.50mmol), palladium acetate (16.0mg, 0.064mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.0678g, 0.125mmol) were suspended in THF (24mL). 2M-potassium phosphate aqueous solution (3.6mL, 6.3mmol) was added to the suspension and stirred at 70°C for 16 hours. After cooling to room temperature, methanol was added and the precipitated solid was filtered. The filtered material was suspended in toluene (60 mL) and heated to 100°C, activated carbon was added, stirred, and then filtered through Celite. The filtrate was concentrated and purified by recrystallization with toluene under an argon atmosphere to obtain 4-[(1,1'-biphenyl)-4-yl]-6-phenyl-2-[4'-(4-benzonitrile)-(1,1':2',1''-terphenyl)-4-yl]pyrimidine (E19) (0.91 g, yield 68%). 1H-NMR(CDCl3)δ(ppm):8.64(d,J=8.0Hz,2H),8.37(d,J=8.8Hz,2H),8.31-8.28(m,2H),8.06(s,1H),7.82-7.76(m ,6H),7.71-7.64(m,5H),7.60-7.54(m,3H),7.50(dd,J=8.8Hz,8.8Hz,2H),7.43-7.36(m,3H),7.28-7.26(m,5H).

[0182] Synthesis Reference Example 20 (Synthesis of E20)

[0183] [ka] Under an argon atmosphere, 4-chloro-6-(4-biphenyl)-2-phenylpyrimidine (3.00 g, 8.8 mmol), 2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-4-(9-phenanthryl)biphenyl (4.81 g, 10.5 mmol), 2M potassium phosphate aqueous solution (13 mL) and tetrakis(triphenylphosphine)palladium (202 mg, 0.18 mmol) were suspended in THF (88 mL) and refluxed for 15 hours. After cooling, water was added to the reaction mixture, and the solid was filtered and washed with water and methanol. The obtained solid was recrystallized with toluene to obtain 4-[4-(9-phenanthryl)biphenyl-2-yl]-6-(4-biphenyl)-2-phenylpyrimidine (E20) (yield 3.54 g, 64%). 1 H-NMR(CDCl3)δ(ppm):8.83(d,J=8.8Hz,2H),8.76(d,J=8.0Hz,1H),8.50-8.47(m,2H),8.24(d,J=1.6Hz,1H),8.12(brd,J =8.8Hz,1H),7.96(dd,J=7.6Hz,1.2Hz,1H),7.94(brd,J=8.4Hz,2H),7.85(s,1H),7.78-7.59(m,10H),7.49-7.34(m,11H).

[0184] The cyclic azine compounds used in the following experimental examples were synthesized by the same means as in the production methods shown in the above synthesis examples.

[0185] [ka]

[0186] <Measurement of sublimation temperature> Purification Example 1 (Example) The white powders (2.66 g) of compounds E1 to E4 were purified by sublimation under vacuum conditions. The results are shown in Table 1. Purification Example 2 (Comparative Example) A white powder (1.50 g) of compound ETL-a (a compound described in Patent Document 3) was purified by sublimation under vacuum conditions. The results are shown in Table 1. Purification Example 3 (Comparative Example) A white powder (1.15 g) of compound ETL-b (a compound described in Patent Document 1) was purified by sublimation under vacuum conditions. The results are shown in Table 1.

[0187] [ka]

[0188] [Table 1]

[0189] The results in Table 1 show that the compound according to one embodiment of the present disclosure is more amorphous than known compounds having a comparable molecular weight and can be purified by sublimation at a lower temperature.

[0190] The structural formulas and abbreviations of the compounds used in the preparation and performance evaluation of the organic electroluminescent device are shown below.

[0191] [ka]

[0192] Element Example 1 (see Figure 2) (Preparation of substrate 101 and anode 102) A glass substrate with an indium-tin oxide (ITO) transparent electrode, on which a 2 mm wide ITO film (thickness: 110 nm) was patterned in stripes, was prepared as a substrate with an anode on its surface. The substrate was then washed with isopropyl alcohol and then subjected to surface treatment with ozone ultraviolet cleaning.

[0193] (Preparation for vacuum deposition) After cleaning and surface treatment, each layer was deposited by vacuum deposition on the substrate by vacuum deposition, so that each layer was laminated. First, the glass substrate was placed in a vacuum deposition chamber and 1.0×10 -4 The pressure was reduced to 10 Pa. Then, each layer was formed according to the film formation conditions in the following order.

[0194] (Fabrication of Hole Injection Layer 103) The sublimation-purified HTL-1 and NDP-9 were formed into a film of 10 nm at a rate of 0.15 nm / sec to form a hole injection layer 103 .

[0195] (Preparation of the first hole transport layer 1051) The sublimation-purified HTL was formed into a film of 85 nm at a rate of 0.15 nm / sec to form a first hole transport layer 1051 .

[0196] (Preparation of second hole transport layer 1052) The sublimation-purified EBL-1 was formed into a film having a thickness of 5 nm at a rate of 0.15 nm / sec to prepare a second hole transport layer 1052 .

[0197] (Fabrication of the Light-Emitting Layer 106) Sublimation-purified BH-1 and BD-1 were mixed in a ratio of 95:5 (mass ratio) to form a film of 20 nm, thereby producing the light-emitting layer 106. The film formation rate was 0.18 nm / sec.

[0198] (Preparation of First Electron Transport Layer 1071) The sublimation-purified HBL-1 was formed into a film of 6 nm at a rate of 0.05 nm / sec to form a first electron transport layer 1071 .

[0199] (Preparation of second electron transport layer 1072) The compound E1 and Liq were mixed in a ratio of 50:50 (mass ratio) to form a film having a thickness of 25 nm, thereby forming a second electron transport layer 1072. The film formation rate was 0.15 nm / sec.

[0200] (Preparation of cathode 108) Finally, a metal mask was placed so as to be perpendicular to the ITO stripes on the substrate, and the cathode 108 was formed. The cathode was a three-layer structure in which ytterbium, silver / magnesium (mass ratio 9 / 1), and silver were formed in that order to thicknesses of 2 nm, 12 nm, and 90 nm, respectively. The deposition rate of ytterbium was 0.02 nm / sec, that of silver / magnesium was 0.5 nm / sec, and that of silver was 0.2 nm / sec.

[0201] As a result, the light-emitting area of ​​4 mm2 shown in Figure 2 2 An organic electroluminescence device 100 was produced. The film thickness of each layer was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0202] Furthermore, this element was sealed in a nitrogen atmosphere glove box with oxygen and moisture concentrations of 1 ppm or less by sealing a glass sealing cap and the film-formed substrate (element) with bisphenol F type epoxy resin (manufactured by Nagase ChemteX Corporation).

[0203] A direct current was applied to the organic electroluminescent device fabricated as described above, and the light-emitting characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse). 2 The current efficiency (cd / A) was measured when current was passed through the electrode. The current efficiency is a relative value with the result in Comparative Example 2 of the element described later taken as the reference value (100). The measurement results are shown in Table 2.

[0204] Element Examples 2 to 19 An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that the compound shown in Table 2 below was used instead of Compound E1 in Element Example 1. The measurement results obtained are shown in Table 2.

[0205] Element comparison examples 1 to 6 An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that the compound shown in Table 2 below was used instead of Compound E1 in Element Example 1. The measurement results obtained are shown in Table 2.

[0206] [Table 2]

[0207] As can be seen from Table 2, the pyrimidine compound (1) according to one embodiment of the present disclosure can provide an organic electroluminescent device that combines excellent current efficiency characteristics with those of conventionally known compounds.

[0208] In addition, the pyrimidine compound (1) according to one embodiment of the present disclosure is used as an electron transport material for an organic electroluminescence device that has both excellent driving voltage characteristics and current efficiency characteristics. Furthermore, the pyrimidine compound (1) can provide an organic electroluminescence device with low power consumption. [Explanation of symbols]

[0209] 100 Organic electroluminescent device 1 Board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Light-emitting layer 6 Electron transport layer 7 Electron injection layer 8 cathode 101 Substrate 102 Anode 103 Hole injection layer 105 Hole transport layer 1051 First hole transport layer 1052 Second hole transport layer 106 Light-emitting layer 107 Electron transport layer 1071 First electron transport layer 1072 Second electron transport layer 108 cathode

Claims

1. A pyrimidine compound represented by formula (1): 【Chemistry 1】 In formula (1), Ar １ teeth, an aromatic group having 5 to 20 carbon atoms, which may be a monocyclic ring, a condensed ring, or a ring or rings connected thereto; The aromatic group is formed by the following ring alone or in combination: Aromatic hydrocarbon rings, a heteroaromatic ring having a Group 16 element, and Heteroaromatic rings consisting of only 6-membered rings and containing one N as a heteroatom; L is, represents an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent; Ar ２ is a structure represented by formula (2-A) or (2-B), The dotted line represents the point of attachment to L; X １１ ~X １４ and X ２１ ~X ２４ represents C-Ra, C-Rb or N; X １１ ~X １４ and X ２１ ~X ２４ Two or more of the following cannot be N at the same time; X １１ ~X １４ Of these, three or more do not become C-Ra at the same time; X ２１ ~X ２４ Of these, two or more do not become C-Ra at the same time; R ２ and Ra is an aromatic group having 5 to 20 carbon atoms, which may be a monocyclic ring, a condensed ring, or a ring or rings connected thereto; The aromatic group is formed by the following ring alone or in combination: Aromatic hydrocarbon rings, A heteroaromatic ring having a Group 16 element and not containing two or more N atoms, and Heteroaromatic rings consisting of only 6-membered rings and containing one N as a heteroatom; R 1 is represents a phenyl group, a biphenylyl group, a naphthyl group, a pyridyl group, a quinolyl group, or an isoquinolyl group; Rb is Hydrogen, deuterium, alkyl groups having 1 to 10 carbon atoms; Two or more of Ra and Rb may be different from each other; 【Chemistry 2】 a represents an integer of 0 to 3; b represents an integer of 1 to 4; a+b is 3 or 4; c represents an integer of 1 to 3; Ar １ , Ar ２ When there are two or more L's, there are two or more Ar １ , Ar ２ , L may be different from each other; Ar １ , Ar ２ , L, R １ , R ２ , Ra and Rb may be substituted with an alkyl group having 1 to 10 carbon atoms or a CN group, and these are Ar １ , L, R １ , R ２ and the number of carbon atoms of the aromatic group forming Ra is not included in the number of carbon atoms. However, Ar １ and Ar ２ does not have the following groups: The dotted lines indicate the points of attachment to other groups. 【Chemistry 3】

2. The pyrimidine compound according to claim 1, wherein the formula (2-A) or (2-B) is any one of the following formulae (2-1) to (2-8): During the ceremony, The dotted line represents the point of attachment to L; X １ ~X ４ represents C—H or N, and X １ ~X ４ Two or more of the following cannot be N at the same time; R ３ is R ２ is synonymous with. 【Chemistry 4】

3. The pyrimidine compound of claim 1 , wherein a+b is 3.

4. 2. The pyrimidine compound according to claim 1, wherein L is optionally substituted phenylene or optionally substituted naphthylene.

5. 2. The pyrimidine compound of claim 1, wherein L is phenylene or naphthylene.

6. The pyrimidine compound according to claim 1, wherein L is selected from formulas (L-1) to (L-12). In the formula, the dotted line represents a pyrimidine moiety, or Ar ２ Represents the bonding point with. 【Chemistry 5】

7. The Ar ２ The pyrimidine compound according to claim 2, wherein is any one of (2-1) to (2-3) and (2-5) to (2-8).

8. The R ２ but, an aromatic group having 5 to 20 carbon atoms, which may be a monocyclic ring, a condensed ring, or a ring or rings connected thereto; The aromatic group is formed by the following ring alone or in combination: an aromatic hydrocarbon ring, and A heteroaromatic ring having a Group 16 element and not containing two or more N atoms. The pyrimidine compound according to claim 1.

9. The R ２ The pyrimidine compound according to claim 1, wherein is a monocyclic, condensed, or aromatic hydrocarbon group having 6 to 20 carbon atoms which may be linked to one another.

10. The Ar １ The pyrimidine compound according to claim 1, wherein the ring constituting the formula (I) is benzene, naphthalene, phenanthrene, pyridine or quinoline.

11. The pyrimidine compound according to claim 1, which is the following (E1) to (E19) or (E21): 【Chemistry 6】

12. An organic electroluminescent device having one or more organic thin film layers including at least a light-emitting layer between an anode and a cathode, wherein at least one of the organic thin film layers contains the pyrimidine compound according to any one of claims 1 to 11.

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