Diamantane compound, material for organic electroluminescent device, and organic electroluminescent device

Abstract

Provided are: a diamantane compound that makes it possible to produce an organic electroluminescence element that achieves excellent light-emission efficiency characteristics or, more preferably, excellent drive voltage characteristics and excellent light-emission efficiency characteristics; and an organic electroluminescence element material that includes the diamantane compound. Also provided is an organic electroluminescence element that achieves high-level light-emission efficiency characteristics or, more preferably, high-level drive voltage characteristics and high-level light-emission efficiency characteristics.　The present invention provides a diamantane compound that includes a group represented by formula (1) and a group represented by formula (2). (In formula (1), the carbon atoms of the diamantane ring may be substituted with a C6–12 aryl group. In formula (1), * indicates a bond. a represents an integer from 1 to 6.) (In formula (2), Ar indicates (i) an optionally substituted C6–60 aromatic hydrocarbon group, (ii) an optionally substituted C3–60 heteroaromatic group, or (iii) a combination of (i) and (ii). However, when Ar has a total of at least 8 carbon atoms and is only the C6–60 aromatic hydrocarbon group of (i), Ar has a total of at least 13 carbon atoms. In formula (2), * indicates a bond. b represents an integer from 1 to 6.)

Description

[Technical Field]

[0001] The present invention relates to a diamantane compound, a material for an organic electroluminescent device, and an organic electroluminescent device. [Background technology]

[0002] Organic electroluminescent devices have begun to be put to practical use, primarily in small mobile devices. However, further expansion of their applications requires improved performance, and materials with low driving voltage and high luminous efficiency are in demand.

[0003] Patent Document 1 discloses an azine compound that is a material for an organic electroluminescent device that is highly efficient and can reduce the driving voltage. Patent Document 2 discloses a compound, which is a material for an organic electroluminescent device, and is represented by a specific structural formula in which a fluorene moiety and a 6-membered heterocycle are bonded via a linker group to form a basic skeleton. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-82136 [Patent Document 2] Special Publication No. 2018-507174 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a strong demand from the market for expanding the range of applications and the environments in which they can be used, and there is a demand for providing organic electroluminescent devices that are even better in terms of the two properties of driving voltage and luminous efficiency. From the viewpoint of providing organic electroluminescent devices that exhibit even better driving voltage and luminous efficiency, the compounds that are materials for organic electroluminescent devices described in Patent Documents 1 and 2 above are not sufficient, and there is room for improvement.

[0006] Therefore, one aspect of the present invention is to provide a compound that is a material for an organic electroluminescent device, which can be used to fabricate an organic electroluminescent device that can exhibit excellent driving voltage characteristics and luminous efficiency characteristics.

[0007] Furthermore, another aspect of the present invention is to provide an organic electroluminescent device that can achieve high levels of driving voltage characteristics and luminous efficiency characteristics. [Means for solving the problem]

[0008] As a result of extensive research to solve the above problems, the present inventors have found that the use of a specific diamantane compound as an electron transport layer or a hole transport layer of an organic electroluminescent element improves the luminous efficiency characteristics, more preferably the driving voltage characteristics and luminous efficiency characteristics of the organic electroluminescent element, and have thus completed the present invention.

[0009] That is, the present invention includes the following aspects. [1] A diamantane compound having a group represented by the following formula (1) and a group represented by the following formula (2): [ka] (In formula (1), a carbon atom in the diamantane ring may be substituted with an aryl group having 6 to 12 carbon atoms. In formula (1), * represents a bond, and a represents an integer of 1 to 6.) [ka] (Ar in formula (2) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). However, the total number of carbon atoms constituting Ar is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group having 6 to 60 carbon atoms as defined in (i) above, the total number of carbon atoms constituting Ar is 13 or more. In formula (2), * represents a bond. b represents an integer of 1 to 6. [2] The diamantane compound according to [1], wherein the diamantane compound is represented by the following formula (3) or the following formula (4): [ka] In the diamantane ring in formula (3), a carbon atom other than the carbon atom bonded to the -Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. In formula (3), each Ar is independently (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group in which the groups (i) and (ii) are combined. However, each Ar in formula (3) independently has a total of 8 or more carbon atoms constituting Ar, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more. In formula (3), m represents an integer of 1, 2, or 3. [ka] (In the diamantane ring in formula (4), each carbon atom other than the carbon atom bonded to the -Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (4) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group in which the groups (i) and (ii) are combined. However, the total number of carbon atoms constituting Ar in formula (4) is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more. In formula (4), n represents an integer of 2 or 3. [3] The diamantane compound according to [2], which is represented by any one of the following formulas (3-1) to (3-3): [ka] [ka] [ka] In the diamantane rings in the formulae (3-1) to (3-3), carbon atoms other than the carbon atom bonded to the -Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (3-1) to formula (3-3) each independently represents (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). However, each Ar in formulas (3-1) to (3-3) independently has a total of 8 or more carbon atoms constituting Ar, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more. [4] The diamantane compound according to [2], which is represented by any one of the following formulas (4-1) and (4-2): [ka] [ka] In the diamantane rings in formulae (4-1) and (4-2), each carbon atom other than the carbon atom bonded to the -Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (4-1) to formula (4-2) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). However, the total number of carbon atoms constituting Ar in formulas (4-1) and (4-2) is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more. [5] The diamantane compound according to any one of [1] to [4], wherein the heteroaromatic group is a single ring or a fused ring containing any one of a nitrogen atom, an oxygen atom, and a sulfur atom, or a linked ring to which any ring selected from these rings is linked. [6] The aromatic hydrocarbon group contains an arylamino group, The diamantane compound according to any one of [1] to [5], wherein the heteroaromatic group contains a heterocyclic amino group. [7] The substituent in the optionally substituted aromatic hydrocarbon group of (i) or the optionally substituted heteroaromatic group of (ii) is a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a formyl group, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, P(═O)(Ar 2 )2, C(=O)Ar 2 , B(Ar 2 )2, B(OAr 2 )2, OSO2Ar 2 , S(=O)Ar 2 , Si(Ar 2 )3, P(=S)(Ar 2)2, and C(=C(CN)2)Ar 2 The diamantane compound according to any one of [1] to [6], wherein the diamantane compound is a group selected from group 2. (The aforementioned Ar 2 is a group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 60 carbon atoms, and a heteroaromatic group having 3 to 60 carbon atoms. [8] The diamantane compound according to [5], which has the optionally substituted heteroaromatic group (ii) having 3 to 60 carbon atoms and containing any one of a nitrogen atom, an oxygen atom, and a sulfur atom. [9] The diamantane compound according to [8], wherein the diamantane compound has the optionally substituted heteroaromatic group (ii) having 3 to 60 carbon atoms and containing a nitrogen atom.

[10] The diamantane compound according to any one of [1] to [9], wherein the diamantane compound has a fused ring aromatic hydrocarbon group having 14 or more carbon atoms.

[11] The diamantane compound according to any one of [1] to

[10] , wherein the diamantane ring has no aryl group substituted on any carbon atom other than the carbon atom bonded to the -Ar group.

[12] A material for an organic electroluminescent device, comprising the diamantane compound according to any one of [1] to

[11] .

[13] The material for organic electroluminescent devices according to

[12] , wherein the material for organic electroluminescent devices is an electron transport material for organic electroluminescent devices or a hole transport material for organic electroluminescent devices.

[14] An organic electroluminescent device containing the diamantane compound according to any one of [1] to

[11] .

[15] A diamantane compound represented by the following formula (5) or (6): [ka] (In the diamantane ring in formula (5), -L 1 -X 1 Carbon atoms other than the carbon atom bonded to the group may be substituted with an aryl group having 6 to 12 carbon atoms. L in equation (5)1 are each independently (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group in which the groups (i) and (ii) are combined. L 1 The total number of carbon atoms that make up the group is 8 or more. X in equation (5) 1 represents a halogen atom or a trifluoromethanesulfonyloxy group. In formula (5), p and q each represent an integer of 1 to 3, and when p is 1, q represents an integer of 1, 2, or 3, and when q is 1, p represents an integer of 1, 2, or 3. [ka] (In the diamantane ring in formula (6), -L 2 -B(OR 1 Carbon atoms other than the carbon atoms bonded to the 2) groups may be substituted with an aryl group having 6 to 12 carbon atoms. L in equation (6) 2 are each independently a single bond, or (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group in which the groups (i) and (ii) are combined. R in equation (6) 1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. B(OR 1 )2 of 2 R 1 may be the same or different. 1 may be joined together to form a ring containing the oxygen atom and the boron atom. In formula (6), p and q each represent an integer of 1 to 3, and when p is 1, q represents an integer of 1, 2, or 3, and when q is 1, p represents an integer of 1, 2, or 3. [Effects of the Invention]

[0010] According to one aspect of the present invention, it is possible to provide a diamantane compound with which an organic electroluminescent element capable of exhibiting excellent luminous efficiency characteristics, more preferably excellent driving voltage characteristics and excellent luminous efficiency characteristics, can be fabricated, and a material for an organic electroluminescent element containing the diamantane compound can be provided.

[0011] According to another aspect of the present invention, an organic electroluminescent device can be provided that can achieve high levels of luminous efficiency characteristics, more preferably high levels of driving voltage characteristics and luminous efficiency characteristics. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view showing an example of a layer structure of an organic electroluminescent device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing another example of the laminated structure of an organic electroluminescent device according to one embodiment of the present invention (structure of Device Example 1). DETAILED DESCRIPTION OF THE INVENTION

[0013] The diamantane compound according to one embodiment of the present invention will be described in detail below.

[0014] <Diamantane compounds> A diamantane compound according to one embodiment of the present invention is a diamantane compound having a group represented by the following formula (1) and a group represented by the following formula (2).

[0015] [ka]

[0016] In formula (1), a carbon atom in the diamantane ring may be substituted with an aryl group having 6 to 12 carbon atoms. In formula (1), * represents a bond. a represents an integer of 1 to 6.

[0017] [ka]

[0018] Ar represented by formula (2) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). However, in Ar represented by formula (2), the total number of carbon atoms constituting Ar is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more. In formula (2), * represents a bond. b represents an integer of 1 to 6.

[0019] [Diamantane ring in formula (1)] In the diamantane ring in formula (1), the carbon atom bonded to the Ar group represented by formula (2) is not particularly limited, and the Ar group represented by formula (2) may be bonded to any carbon atom within the diamantane skeletal structure represented by formula (1). In addition, in the diamantane ring in formula (1), the number of carbon atoms bonded to the Ar group represented by formula (2) is not particularly limited, and multiple carbon atoms in the diamantane ring in formula (1) can be bonded to the Ar group represented by formula (2). As described above, in the diamantane ring in formula (1), carbon atoms other than the carbon atom bonded to the Ar group represented by formula (2) may be substituted with an aryl group having 6 to 12 carbon atoms. However, in the present invention, from the viewpoints of availability, ease of preparation, etc., it is more preferable that no aryl group is substituted with any carbon atoms other than the carbon atom bonded to the Ar group in the diamantane ring in formula (1). Here, examples of the aryl group as a substituent include a phenyl group, a naphthyl group, and a biphenyl group.

[0020] [Regarding Ar in formula (2)] Ar is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group in which the groups (i) and (ii) are combined. The aromatic hydrocarbon group and heteroaromatic group may each be in the form of a single ring, a condensed ring, or a linked ring in which any ring selected from these rings is linked.

[0021] Examples of aromatic hydrocarbon groups having 6 to 60 carbon atoms include a phenyl group, a naphthyl group, a phenanthryl group, an anthryl group, a pyrenyl group, a perylenyl group, a fluorenyl group, a dimethylfluorenyl group, a diphenylfluorenyl group, a triphenylenyl group, a fluoranthenyl group, a benzofluoranthenyl group, a chrysenyl group, a dibenzochrysenyl group, and a dinaphthochrysenyl group. In the present invention, the aromatic hydrocarbon group also includes an arylamino group. An arylamino group refers to a group in which one or both hydrogen atoms of an amino group are substituted with an aryl group. Examples of the arylamino group include a phenylamino group, a diphenylamino group, a biphenylylamino group, a dibiphenylylamino group, a naphthylamino group, and a dinaphthylamino group. In the present invention, the aromatic hydrocarbon group having 6 to 60 carbon atoms is more preferably a fused ring aromatic hydrocarbon group having 14 or more carbon atoms.

[0022] The heteroaromatic group is preferably, for example, a heteroaromatic group containing any one of a nitrogen atom, an oxygen atom, and a sulfur atom, and among these, a heteroaromatic group containing a nitrogen atom is preferred. Examples of heteroaromatic groups having 3 to 60 carbon atoms include a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazinyl group, a quinolyl group, an isoquinolyl group, a dithyridinyl group, an acridinyl group, a phenanthrolinyl group, a phenanthridinyl group, a pyrrolyl group, an indolyl group, an indolizinyl group, a carbazolyl group, a carbolinyl group, a benzocarbazolyl group, a benzocarbolinyl group, a furanyl group, a benzofuranyl group, a dibenzofuranyl group, a xanthenyl group, a spiroxanthenyl group, a benzoxanthenyl group, a thienyl group, a benzothienyl group, a dibenzothienyl group, an oxazolyl group, a benzoxazolyl group, a thiazolyl group, and a benzothiazalyl group. In the present invention, the heteroaromatic group also includes a heterocyclic amino group. A heterocyclic amino group refers to a group in which one or both hydrogen atoms of an amino group are substituted with a heteroaromatic group. Examples of heterocyclic amino groups include a pyridylamino group, a dipyridylamino group, a pyrimidylamino group, a dipyrimidylamino group, a pyrazylamino group, and a dipyrazylamino group.

[0023] Examples of the substituent in the optionally substituted aromatic hydrocarbon group of (i) or the optionally substituted heteroaromatic group of (ii) include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a formyl group, a cyano group, a nitro group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, P(═O)(Ar 2 )2, C(=O)Ar 2 , B(Ar 2 )2, B(OAr 2 )2, OSO2Ar 2 , S(=O)Ar 2 , Si(Ar 2 )3, P(=S)(Ar 2 )2, and C(=C(CN)2)Ar 2 Examples of the group include groups selected from the group 2. Here, the above Ar 2Examples of the group include a group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 60 carbon atoms, and a heteroaromatic group having 3 to 60 carbon atoms.

[0024] Ar in the above formula (2) preferably has a group selected from the group consisting of a phenyl group, a naphthyl group, an azabenzofluoranthenyl group, a triazinyl group, a fluoranthenyl group, a benzofluoranthenyl group, and a triazinylphenyl group.

[0025] Preferred embodiments of the diamantane compound of the present invention having a group represented by the above formula (1) and a group represented by the above formula (2) include a diamantane compound represented by the following first aspect or a diamantane compound represented by the following second aspect. The diamantane compound represented by the first embodiment and the diamantane compound represented by the second embodiment will be described below.

[0026] [First aspect] A preferred embodiment of the diamantane compound of the present invention is a diamantane compound represented by the following formula (3).

[0027] [ka]

[0028] In the diamantane ring in formula (3), the carbon atoms other than the carbon atom bonded to the Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. In formula (3), each Ar is independently (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group in which the groups (i) and (ii) are combined. However, each Ar in formula (3) independently has a total of 8 or more carbon atoms constituting Ar, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more. In formula (3), m represents an integer of 1, 2, or 3.

[0029] Furthermore, preferred embodiments of the diamantane compound represented by the above formula (3) include diamantane compounds represented by any of the following formulas (3-1) to (3-3).

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] In the diamantane rings in the formulae (3-1) to (3-3), carbon atoms other than the carbon atom bonded to the -Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (3-1) to formula (3-3) each independently represents (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). However, each Ar in formulas (3-1) to (3-3) independently has a total of 8 or more carbon atoms constituting Ar, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more.

[0034] In the above formula (3) and the above formulas (3-1) to (3-3), the explanations regarding the diamantyl group and the Ar group are as described above in the section [Diamantane ring in formula (1)] and the section [Regarding Ar in formula (2)].

[0035] [Second aspect] A preferred embodiment of the diamantane compound of the present invention is a diamantane compound represented by the following formula (4).

[0036] [ka]

[0037] In the diamantane ring in formula (4), each carbon atom other than the carbon atom bonded to the -Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (4) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). However, the total number of carbon atoms constituting Ar in formula (4) is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more. In formula (4), n represents an integer of 2 or 3.

[0038] Furthermore, preferred embodiments of the diamantane compound represented by the above formula (4) include diamantane compounds represented by any one of the following formulas (4-1) and (4-2).

[0039] [ka]

[0040] [ka]

[0041] In the diamantane rings in formulae (4-1) and (4-2), each carbon atom other than the carbon atom bonded to the -Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (4-1) to formula (4-2) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). However, the total number of carbon atoms constituting Ar in formulas (4-1) and (4-2) is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more.

[0042] In the above formula (4) and the above formulas (4-1) and (4-2), the explanations regarding the diamantyl group and the Ar group are as described above in the section [Diamantane ring in formula (1)] and the section [Regarding Ar in formula (2)].

[0043] The molecular weight of the diamantane compound of the present invention, as determined by mass spectrometry, is preferably 300 to 1200, more preferably 400 to 900. Diamantane compounds having a molecular weight within the above range have a high glass transition point and are highly stable even when repeatedly subjected to electrical oxidation and reduction. Therefore, by using the diamantane compound of the present invention having a desired molecular weight as a material for an organic electroluminescent element, it is possible to provide an organic electroluminescent element that can achieve even higher levels of driving voltage characteristics and luminous efficiency characteristics.

[0044] [Specific examples of diamantane compounds] Specific examples of the diamantane compound are shown below, but the present invention is not limited to these.

[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056] [Method for producing diamantane compounds] A method for producing a diamantane compound will now be described. The diamantane compound according to the present invention can be produced by appropriately combining known reactions (such as Suzuki-Miyaura cross-coupling reaction) that are commonly used by those skilled in the art as a method for synthesizing aromatic compounds. For example, it can be produced by the methods shown in the following synthetic routes (i) to (iii).

[0057] [ka]

[0058] [ka]

[0059] [ka]

[0060] In the above synthesis routes (i) to (iii), L, Ar 1 , R 1 , X 1 , X 2 , p, and q are as follows: Each L is independently a single bond, or (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). Ar 1 are each independently (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group in which the groups (i) and (ii) are combined. X 1 and X 2 represents a halogen atom or a trifluoromethanesulfonyloxy group. R 1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. B(OR 1 )2 of 2 R 1 may be the same or different. 1 may be joined together to form a ring containing the oxygen atom and the boron atom. p and q each represent an integer of 1 to 3; when p is 1, q represents an integer of 1, 2 or 3; when q is 1, p represents an integer of 1, 2 or 3; -L-Ar 1 has the same meaning as -Ar in formula (2).

[0061] X 1 and X 2 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom or a bromine atom is preferred in terms of inexpensive raw materials. B(OR) in boron compounds 1 )2 is not particularly limited, but examples thereof include B(OH)2, B(OMe)2, B(OiPr)2, B(OBu)2, and B(OPh)2. Note that Me represents a methyl group, iPr represents an isopropyl group, Bu represents a butyl group, and Ph represents a phenyl group. In addition, two R 1 When these are united to form a ring containing an oxygen atom and a boron atom, B(OR 1 Examples of 2) are not particularly limited, but include the following groups (I) to (VI), with the group (II) being preferred in terms of good yield.

[0062] [ka]

[0063] The coupling reaction in synthetic routes (ii) and (iii) is a method of reacting an aryl halide compound with a boron compound in the presence of a palladium catalyst and a base, and general reaction conditions for the Suzuki-Miyaura reaction can be applied. The boron compound used in the coupling reaction can be produced according to the method disclosed in, for example, The Journal of Organic Chemistry, Vol. 60, p. 7508, 1995 or The Journal of Organic Chemistry, Vol. 65, p. 164, 2000. Commercially available products may also be used. The aryl halide used in the coupling reaction can be produced, for example, according to the method described in Journal of the American Chemical Society, Vol. 74, p. 6289, 1952, or Synlett, p. 808, 2002. Commercially available products may also be used. There are no particular restrictions on the molar equivalent of the aryl halide used, but it is preferable to use 0.5 to 3.0 molar equivalents relative to the boron compound in terms of good reaction yield. The palladium catalyst used in the coupling reaction is not particularly limited, but specific examples include palladium salts such as palladium chloride, palladium acetate, palladium trifluoroacetate, and palladium nitrate. Further examples include complex compounds such as π-allylpalladium chloride dimer, palladium acetylacetonate, tris(dibenzylideneacetone)dipalladium, bis(dibenzylideneacetone)palladium, dichlorobis(acetonitrile)palladium, and dichlorobis(benzonitrile)palladium, as well as palladium complexes having a tertiary phosphine as a ligand, such as dichlorobis(triphenylphosphine)palladium, tetrakis(triphenylphosphine)palladium, dichloro(1,1'-bis(diphenylphosphino)ferrocene)palladium, bis(tri-tert-butylphosphine)palladium, bis(tricyclohexylphosphine)palladium, and dichlorobis(tricyclohexylphosphine)palladium. These can also be prepared in the reaction system by adding a tertiary phosphine to a palladium salt or complex compound. Examples of tertiary phosphines that can be used in this case include triphenylphosphine, trimethylphosphine, tributylphosphine, tri(tert-butyl)phosphine, tricyclohexylphosphine, tert-butyldiphenylphosphine, 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene, 2-(diphenylphosphino)-2'-(N,N-dimethylamino)biphenyl, 2-(di-tert-butylphosphino)biphenyl, 2-(dicyclohexylphosphino)biphenyl, bis(diphenylphosphine), Examples of the bis(diphenylphosphino) include 1,2-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,1'-bis(diphenylphosphino)ferrocene, tri(2-furyl)phosphine, tri(o-tolyl)phosphine, tris(2,5-xylyl)phosphine, (±)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl. Among these, palladium complexes having a tertiary phosphine as a ligand are preferred in terms of good yield, and palladium complexes having 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl as a ligand are even more preferred. The molar ratio of the tertiary phosphine to the palladium salt or complex compound is preferably in the range of 1:10 to 10:1, and more preferably in the range of 1:2 to 3:1 in terms of good yield. There is no limitation on the amount of palladium catalyst used in the above-mentioned coupling reaction, but in terms of good yield, the molar equivalent of the palladium catalyst is preferably in the range of 0.005 to 0.5 molar equivalents relative to the boron compound. The base used in the coupling reaction is not particularly limited, but examples thereof include metal hydroxide salts such as sodium hydroxide, potassium hydroxide, and calcium hydroxide; metal carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, and cesium carbonate; metal acetates such as potassium acetate and sodium acetate; metal phosphates such as potassium phosphate and sodium phosphate; metal fluoride salts such as sodium fluoride, potassium fluoride, and cesium fluoride; and metal alkoxides such as sodium methoxide, potassium methoxide, sodium ethoxide, potassium isopropyl oxide, and potassium tert-butoxide. Among these, metal carbonates and metal phosphates are preferred in terms of good reaction yield, with potassium carbonate or potassium phosphate being more preferred. The amount of base used is not particularly limited, but in terms of good reaction yield, the molar ratio of the base to the boron compound is preferably in the range of 1:2 to 10:1, and more preferably in the range of 1:1 to 4:1. The coupling reaction can be carried out in a solvent. Solvents that can be used in the above-mentioned coupling reaction include water, ethers such as diisopropyl ether, dibutyl ether, cyclopentyl methyl ether (CPME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, and dimethoxyethane, aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, and tetralin, carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and 4-fluoroethylene carbonate, ethyl acetate, butyl acetate, methyl propionate, methyl propionate, methyl butyrate, and γ-lanthate. Examples of suitable solvents include esters such as methacrylate, amides such as N,N-dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP), ureas such as N,N,N',N'-tetramethylurea (TMU) and N,N'-dimethylpropyleneurea (DMPU), and alcohols such as dimethyl sulfoxide (DMSO), methanol, ethanol, isopropyl alcohol, butanol, octanol, benzyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and 2,2,2-trifluoroethanol, and may be mixed in any ratio. The amount of solvent used is not particularly limited. Among these, water, ethers, amides, alcohols, or mixed solvents thereof are preferred in terms of high reaction yield, and a mixed solvent of THF and water is even more preferred. The above-mentioned coupling reaction can be carried out at a temperature appropriately selected from 0°C to 200°C, and is preferably carried out at a temperature appropriately selected from 100°C to 160°C in terms of good reaction yield. The above-mentioned coupling reaction can be carried out by carrying out a usual treatment after the completion of the coupling reaction, and if necessary, the product can be purified by recrystallization, column chromatography, sublimation, preparative HPLC, or the like.

[0064] [Intermediate of diamantane compounds] The diamantane compounds represented by the following formula (5) or (6) used in the above-described synthetic routes (i) to (iii) are effective intermediates for producing the diamantane compound of the present invention. By using these intermediates, the diamantane compound of the present invention can be obtained efficiently and in high yield.

[0065] [ka] (In the diamantane ring in formula (5), -L 1 -X 1 Carbon atoms other than the carbon atom bonded to the group may be substituted with an aryl group having 6 to 12 carbon atoms. L in equation (5) 1 are each independently (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). L 1 The total number of carbon atoms that make up the group is 8 or more. X in equation (5) 1 represents a halogen atom or a trifluoromethanesulfonyloxy group. In formula (5), p and q each represent an integer of 1 to 3, and when p is 1, q represents an integer of 1, 2, or 3, and when q is 1, p represents an integer of 1, 2, or 3.

[0066] [ka] (In the diamantane ring in formula (6), -L 2 -B(OR 1 Carbon atoms other than the carbon atoms bonded to the 2) groups may be substituted with an aryl group having 6 to 12 carbon atoms. L in equation (6) 2 are each independently a single bond, or (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) A group formed by combining the groups (i) and (ii). R in equation (6) 1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. B(OR 1 )2 of 2 R 1 may be the same or different. 1 may be joined together to form a ring containing the oxygen atom and the boron atom. In formula (6), p and q each represent an integer of 1 to 3, and when p is 1, q represents an integer of 1, 2, or 3, and when q is 1, p represents an integer of 1, 2, or 3.

[0067] <Materials for organic electroluminescent devices> Diamantane compounds are useful as materials for organic electroluminescent devices. The diamantane compounds can be used, for example, as electron transport materials for organic electroluminescent devices or hole transport materials for organic electroluminescent devices. Materials for organic electroluminescent devices containing diamantane compounds exhibit high luminous efficiency, more preferably low driving voltage and high luminous efficiency, and can be used to produce organic electroluminescent devices that can be used for a variety of purposes or in a variety of environments.

[0068] <Organic electroluminescent device> An organic electroluminescent device containing a diamantane compound (hereinafter, sometimes simply referred to as an organic electroluminescent device) will be described below.

[0069] The organic electroluminescent device according to one aspect of the present invention contains a diamantane compound.

[0070] The configuration of the organic electroluminescent device is not particularly limited, but examples thereof include the following configurations (i) to (v). (i): Anode / Emitting layer / Cathode (ii): Anode / hole transport layer / light-emitting layer / cathode (iii): Anode / 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

[0071] The diamantane compound may be contained in any of the above layers. In one embodiment, however, in terms of excellent light-emitting properties of the organic electroluminescent device, it is preferable that the diamantane compound be 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. Alternatively, in another embodiment, it 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 anode.

[0072] Therefore, in the case of the configurations (i) to (v) above, in one embodiment, the diamantane compound is preferably contained in one or more layers selected from the group consisting of an emitting layer, an electron transport layer, and an electron injection layer. Alternatively, in the above-mentioned other embodiment, the diamantane compound is preferably contained in one or more layers selected from the group consisting of a light-emitting layer, a hole-transporting layer, and a hole-injecting layer.

[0073] Hereinafter, an organic electroluminescent device according to one embodiment of the present invention will be described in more detail with reference to FIG. 1, taking the above configuration (v) as an example.

[0074] 1 has a so-called bottom-emission type element configuration, the organic electroluminescent element according to one embodiment of the present invention is not limited to the bottom-emission type element configuration. That is, the organic electroluminescent element according to one embodiment of the present invention may have another known element configuration, such as a top-emission type.

[0075] FIG. 1 is a schematic cross-sectional view showing an example of a layer structure of an organic electroluminescent device containing a diamantane compound according to one embodiment of the present invention.

[0076] The organic electroluminescent device 100 comprises, in this order, 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. 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.

[0077] Alternatively, a single layer having the functions of multiple layers, such as an electron injection / transport layer having the functions of both an electron injection layer and an electron transport 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 may each be composed of multiple layers.

[0078] <<Layer containing a diamantane compound>> 1, when the diamantane compound is 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, the organic electroluminescent device 100 contains the diamantane 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. It is preferable that the electron transport layer 6 contains the diamantane compound. The diamantane compound may be contained in multiple layers of the organic electroluminescent device. In addition, in an embodiment in which the diamantane compound is contained in one or more layers selected from the group consisting of the light-emitting layer, the hole-transport layer, and the hole-injection layer, the organic electroluminescent device 100 contains the diamantane compound in one or more layers selected from the group consisting of the light-emitting layer 5, the hole-transport layer 4, and the hole-injection layer 3. It is preferable that the hole-transport layer 4 contains the diamantane compound. The diamantane compound may be contained in multiple layers of the organic electroluminescent device.

[0079] Hereinafter, the organic electroluminescent device 100 will be described taking as an example a case where the electron transport layer 6 contains a diamantane compound.

[0080] [Board 1] The substrate 1 is not particularly limited as long as it is a commonly used substrate, and examples thereof include a glass plate, a quartz plate, a plastic plate, a plastic film, etc. Among these, a glass plate, a quartz plate, and a light-transmitting plastic film are preferred.

[0081] Examples of light-transmitting plastic films include films made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), etc.

[0082] In the case where light is extracted from the substrate 1 side, the substrate 1 is transparent to the wavelength of the emitted light.

[0083] [Anode 2] An anode 2 is provided on the substrate 1 (on the hole injection layer 3 side). Examples of anode materials include metals, alloys, electrically conductive compounds, and mixtures thereof, each having a large work function (e.g., 4 eV or more). Specific examples of anode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO, and ZnO. In the case of an organic electroluminescent device configured so that light is extracted through the anode, the anode is formed from a conductive transparent material that is transparent or substantially transparent to the light emitted.

[0084] [Hole injection layer 3, hole transport layer 4] Between the anode 2 and the 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.

[0085] The hole injection layer 3 and the hole transport layer 4 have the function of transporting holes injected from the anode to the light-emitting layer. By interposing the hole injection layer 3 and the hole transport layer 4 between the anode 2 and the light-emitting layer 5, a large number of holes can be injected into the light-emitting layer 5 with a lower electric field.

[0086] The hole injection layer 3 and the hole transport layer 4 also function as electron blocking layers. That is, electrons injected from the cathode 8 and transported from the electron injection layer 7 and / or the electron transport layer 6 to the light-emitting layer 5 are prevented from leaking to the hole injection layer 3 and / or the hole transport layer 4 by the electron barrier present at the interface between the light-emitting layer 5 and the hole injection layer 3 and / or the hole transport layer 4. As a result, the electrons accumulate at the interface within the light-emitting layer 5, which brings about effects such as improved luminous efficiency, and an organic electroluminescent device with excellent luminous performance is obtained.

[0087] The material for the hole injection layer 3 and the hole transport layer 4 has at least one of hole injection property, hole transport property, and electron barrier property. The material for the hole injection layer 3 and the hole transport layer 4 may be either an organic compound or an inorganic substance.

[0088] Specific examples of materials for the hole injection layer 3 and the hole transport layer 4 include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers (particularly thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds.

[0089] Among these, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferred in terms of good performance of the organic electroluminescent device, and aromatic tertiary amine compounds are particularly preferred.

[0090] Specific examples of the aromatic tertiary amine compound and the styrylamine compound include N,N,N',N'-tetraphenyl-4,4'-diaminophenyl, N,N'-diphenyl-N,N'-bis(m-tolyl)-[1,1'-biphenyl]-4,4'-diamine (TPD), 2,2-bis(4-di-p-tolylaminophenyl)propane, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl, 1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane, bis(4-dimethylamino-2-methylphenyl)phenylmethane, bis(4-di-p-tolylaminophenyl)phenylmethane, N,N'-diphenyl-N,N'- Examples include di(4-methoxyphenyl)-4,4'-diaminobiphenyl, N,N,N',N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis(diphenylamino)quadriphenyl, N,N,N-tri(p-tolyl)amine, 4-(di-p-tolylamino)-4'-[4-(di-p-tolylamino)styryl]stilbene, 4-N,N-diphenylamino-(2-diphenylvinyl)benzene, 3-methoxy-4'-N,N-diphenylaminostilbenzene, N-phenylcarbazole, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD), and 4,4',4''-tris[N-(m-tolyl)-N-phenylamino]triphenylamine (MTDATA).

[0091] Furthermore, examples of materials for the hole injection layer 3 and the hole transport layer 4 include inorganic compounds such as p-type Si and p-type SiC.

[0092] The hole injection layer 3 and the hole transport layer 4 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.

[0093] [Emitting layer 5] The light-emitting layer 5 is provided between the hole transport layer 4 and the electron transport layer 6 . Examples of the material for the light-emitting layer 5, that is, the light-emitting material, include phosphorescent materials, fluorescent materials, and thermally activated delayed fluorescent materials. In the light-emitting layer 5, electron-hole pairs recombine, resulting in light emission.

[0094] The light-emitting layer 5 may consist of a single small molecule or single polymer 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.

[0095] Examples of the host material include compounds having a biphenylyl group, a fluorenyl group, a triphenylsilyl group, a carbazole group, a pyrenyl group, and an anthryl group. More specific examples include 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl (DPVBi), 4,4'-bis(9-ethyl-3-carbazovinylene)1,1'-biphenyl (BCzVBi), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (TBADN), 9,10-di(2-naphthyl)anthracene (ADN), 4,4'-bis(carbazol-9-yl)biphenyl (ADN), 4,4'-bis(carbazol-9-yl)-2,2'-dimethylbiphenyl (CDBP), 2-(9-phenylcarbazol-3-yl)-9-[4-(4-phenylphenylquinazolin-2-yl)carbazole, 9,10-bis(biphenyl)anthracene, and the like.

[0096] Examples of fluorescent dopants include anthracene, pyrene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, quinacridone, dicyanomethylenepyran compounds, thiopyran compounds, polymethine compounds, pyrylium, thiapyrylium compounds, fluorene derivatives, periflanthene derivatives, indenoperylene derivatives, bis(azinyl)amine boron compounds, bis(azinyl)methane compounds, carbostyril compounds, boron compounds, cyclic amine compounds, etc. The fluorescent dopant may be a combination of two or more selected from these.

[0097] Examples of phosphorescent dopants include complexes of metals such as iridium, platinum, palladium, and osmium.

[0098] Specific examples of fluorescent dopants and phosphorescent dopants include tris(8-hydroxyquinoline)aluminum (Alq3), 4,4'-bis[4-(di-p-tolylamino)styryl]biphenyl (DPAVBi), perylene, bis[2-(4-n-hexylphenyl)quinoline](acetylacetonate)iridium(III), Ir(PPy)3 (tris(2-phenylpyridine)iridium(III)), and bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III)) (FIrPic).

[0099] Furthermore, the luminescent material is not limited to being contained only in the luminescent layer 5. For example, the luminescent material may be contained in a layer adjacent to the luminescent layer 5 (the hole transport layer 4 or the electron transport layer 6). This can further increase the luminous efficiency of the organic electroluminescent device 100.

[0100] The light-emitting layer 5 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 or different compositions.

[0101] [Electron transport layer 6] Between the light-emitting layer 5 and the electron injection layer 7, an electron transport layer 6 is provided. The electron transport layer 6 has a function of transporting electrons injected from the cathode 8 to the light-emitting layer. By interposing the electron transport layer 6 between the cathode 8 and the light-emitting layer 5, electrons are injected into the light-emitting layer 5 at a lower electric field.

[0102] As described above, the electron transport layer 6 preferably contains a diamantane compound. In addition to the diamantane compound, the electron transport layer 6 may further contain one or more types selected from conventionally known electron transport materials.

[0103] In addition, when the diamantane compound is not contained in the electron transport layer 6 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 6.

[0104] Conventionally known electron transporting materials include alkali metal compounds, alkaline earth metal compounds, transition metal compounds, zinc group element compounds, earth metal compounds, etc. Examples of alkali metal compounds, alkaline earth metal compounds, transition metal compounds, zinc group element compounds, earth metal compounds, etc. include 8-hydroxyquinolinatolithium (Liq), bis(8-hydroxyquinolinato)zinc, bis(8-hydroxyquinolinato)copper, bis(8-hydroxyquinolinato)manganese, tris(8-hydroxyquinolinato)aluminum, tris(2-methyl-8-hydroxyquinolinato)aluminum, tris(8-hydroxyquinolinato)aluminum, tris(8-hydroxyquinolinato) bis(2-methyl-8-quinolinato)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-naphtholatealuminum, and bis(2-methyl-8-quinolinato)-2-naphtholategallium are examples of chelate-type aryloxides.

[0105] The electron transport layer 6 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 or different compositions.

[0106] In the organic electroluminescent device 100, an electron injection layer 7 may be provided for the purpose of improving electron injection properties and improving device characteristics (for example, luminous efficiency, low-voltage driving, or high durability).

[0107] [Electron injection layer 7] An electron injection layer 7 is provided between the electron transport layer 6 and a cathode 8, which will be described later. The electron injection layer 7 has a function of transferring electrons injected from the cathode to the light-emitting layer 5. By interposing the electron injection layer between the cathode 8 and the light-emitting layer 5, electrons are injected into the light-emitting layer 5 at a lower electric field.

[0108] Examples of materials for the electron injection layer 7 include organic compounds such as fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylene tetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane, and anthrone.

[0109] Further, examples of materials for the electron injection layer 7 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, LiF, C, and Yb.

[0110] [Cathode 8] A cathode 8 is provided on the electron injection layer 7 . In the case of an organic electroluminescence element configured so that only light emitted through the anode 8 is extracted, the cathode 8 can be formed from any conductive material. Examples of materials for the cathode 8 include metals with a low work function (hereinafter also referred to as electron injection metals), alloys, electrically conductive compounds, and mixtures thereof. Here, the metals with a low work function are, for example, metals with a work function of 4 eV or less.

[0111] Specific examples of materials for the cathode 8 include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture, indium, lithium / aluminum mixture, and rare earth metals.

[0112] Among these, from the viewpoints of electron injection properties and durability against oxidation, etc., mixtures of an electron-injecting metal and a second metal that has a larger and more stable work function than the electron-injecting metal, such as magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al2O3) mixtures, and lithium / aluminum mixtures, are preferred.

[0113] [Hole blocking layer] As described above, the organic electroluminescent device 100 may further be provided with a hole blocking layer. Although not shown in FIG. 1, for example, a hole blocking layer can be provided between the light-emitting layer 5 and the electron-transporting layer 6. The hole blocking layer has a role of improving the luminous efficiency by, for example, suppressing leakage of holes from the light emitting layer and increasing the probability of recombination of electrons and holes. Specific examples of materials for the hole blocking layer include triazine derivatives, pyrimidine derivatives, fluoranthene derivatives, polycyclic aromatic hydrocarbon compounds, carbazole derivatives, fluorene derivatives, and spirofluorene derivatives.

[0114] In an embodiment in which the hole transport layer 4 of the organic electroluminescent device 100 contains a diamantane compound, the diamantane compound is used as the material for the hole transport layer 4 in the configuration described above for the organic electroluminescent device 100. The hole transport layer 4 may further contain, in addition to the diamantane compound, one or more types selected from conventionally known hole transport materials. Furthermore, conventionally known electron transport materials can be used for the electron transport layer 6.

[0115] [How each layer is formed]

[0116] Each layer except for the electrodes (anode and 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 for each layer may be used alone or, if necessary, together with a material such as a binder resin or a solvent.

[0117] There are no particular limitations on the thickness of each layer thus formed, and it can be selected appropriately depending on the situation, but it is usually in the range of 5 nm to 5 μm.

[0118] The anode 1 and the cathode 8 can be formed by thinning an electrode material by a method such as vapor deposition or sputtering. A pattern may be formed using a mask of a desired shape during vapor deposition or sputtering, or a pattern of a desired shape may be formed by photolithography or the like after forming a thin film by vapor deposition or sputtering.

[0119] The thickness of the anode 1 and the cathode 8 is preferably 1 μm or less, and more preferably 10 nm or more and 200 nm or less.

[0120] When a layer containing a diamantane compound is formed as an electron transport layer, it may be used in combination with, for example, the above-mentioned conventionally known electron transport material. For example, the diamantane compound and the conventionally known electron transport material may be co-deposited, or a layer of the conventionally known electron transport material may be laminated on the layer of the diamantane compound. When a layer containing a diamantane compound is formed as a hole transport layer, it may be used in combination with, for example, the above-mentioned conventionally known hole transport material. Thus, for example, the diamantane compound and the conventionally known hole transport material may be co-deposited, or a layer of the conventionally known hole transport material may be laminated on a layer of the diamantane compound.

[0121] The organic electroluminescent device according to one embodiment of the present invention may be used as a kind of lamp for illumination or exposure light source, or may be used as a projection device that projects an image onto a screen or the like, or as a display device that directly displays still images or moving images.

[0122] When the organic electroluminescent device according to one embodiment of the present invention is used as a display device for playing moving images, the driving method may be a passive matrix method or an active matrix method. In addition, by using two or more kinds of organic electroluminescent devices having different emission colors, it is possible to fabricate a full-color display device.

[0123] When the diamantane compound is used in an electron transport layer or a hole transport layer, it can provide an organic electroluminescent device having significantly superior luminous efficiency compared to conventionally known azine compounds or amine compounds. In particular, when the diamantane compound is used in an electron transport layer, it can provide an organic electroluminescent device having significantly superior driving voltage and luminous efficiency compared to conventionally known azine compounds.

[0124] Therefore, it is expected that the driving stability and luminous efficiency of organic electroluminescent devices will be improved. Diamantane compounds have a low refractive index, which improves light extraction efficiency and contributes to improving luminous efficiency. Furthermore, due to their characteristic skeleton, diamantane compounds have high chemical stability and can contribute to extending the life of organic electroluminescent devices.

[0125] The diamantane compound can be used as an electron transport layer or a hole transport layer of an organic electroluminescent element, thereby providing a diamantane compound that can achieve low-voltage operation and high efficiency of the element at a high level.Furthermore, an organic electroluminescent element that can exhibit low-voltage operation and high efficiency using the diamantane compound can be provided. [Example]

[0126] The present invention will be described in more detail below based on examples, but the present invention should not be construed as being limited to these examples.

[0127] [ 1 H-NMR measurement] 1 H-NMR spectra were measured using a Bruker ASCEND 400 (400 MHz; manufactured by BRUKER). 1H-NMR spectra were measured using deuterated chloroform (CDCl3) as the measurement solvent and tetramethylsilane (TMS) as the internal standard. Commercially available reagents were used.

[0128] [DSC measurement (glass transition temperature, crystallization temperature, melting point)] The glass transition temperature, crystallization temperature, and melting point were measured using a DSC7020 (product name, manufactured by Hitachi High-Tech Science Corporation).

[0129] The DSC measurement conditions are as follows. The measurement was carried out under a nitrogen atmosphere (flow rate 50 mL / min). The measurement was carried out in the order of first heating, first cooling, and second heating. The glass transition temperature, crystallization temperature, and melting point during the second heating were taken as the glass transition temperature, crystallization temperature, and melting point of the sample, respectively. Sample amount: 5 to 10 mg Measurement conditions: <Fast Heating> Heating rate: 15℃ / min Measurement temperature range: 30℃~360℃ <First cooling> Rapid cooling with dry ice <Second heating> Heating rate: 5℃ / min Measurement temperature range: 30℃~360℃

[0130] [Emission characteristics measurement] The light-emitting characteristics of the organic electroluminescent device were evaluated by applying a direct current to the fabricated device in a 25° C. environment using a luminance meter BM-9 (product name, manufactured by Topcon Technohouse Corporation).

[0131] (Synthesis Example 1)

[0132] [ka] Diamantane (2.40 g, 12.8 mmol) was suspended in trifluoroacetic acid (18 mL). A 50% aqueous solution of nitric acid (61 μL) was added to this suspension and stirred at 50°C for 16 hours. After cooling to room temperature, the solvent was distilled off, and a 10% ethanol solution of potassium hydroxide, diethyl ether, and saturated saline were added to separate the organic layer. Sodium sulfate was added to the organic layer, and the mixture was allowed to stand. The drying agent was then filtered off, and the filtrate was concentrated under reduced pressure. A solid was obtained which was a mixture of 1-hydroxydiamantane (a) and 4-hydroxydiamantane (b). The resulting solid was purified by silica gel column chromatography (hexane / ethyl acetate) to separate 1.12 g of 1-hydroxydiamantane (white solid, 43% yield) and 0.88 g of 4-hydroxydiamantane (white solid, 36% yield). The following synthesis was carried out using each of the separated compounds.

[0133] (a) 1-hydroxydiamantane 1 H-NMR(CDCl3)δ(ppm):2.16-2.18(m,1H),2.13-2.15(n,1H),2.03-2.08(m,1H),1.94-1. 97(m,2H),1.72-1.76(m,1H),1.61-1.67(m,11H),1.45-1.47(m,1H),1.41-1.44(m,1H). (b) 4-hydroxydiamantane 1 H-NMR(CDCl3)δ(ppm):1.92-1.96(m,3H),1.77-1.81(m,1H),1.74-1.76(m,6H),1.69-1.71(m,9H).

[0134] (Synthesis Example 2)

[0135] [ka] 1-Hydroxydiamantane (1.69 g, 8.28 mmol) obtained in Synthesis Example 1 was suspended in thionyl chloride (4.5 mL, 58.0 mmol) and stirred at room temperature for 1 hour. After stirring, low-boiling components were distilled off under reduced pressure. The resulting solid was purified by silica gel column chromatography (hexane) to obtain 1-chlorodiamantane as a white solid (1.54 g, 84% yield). 1 H-NMR(CDCl3)δ(ppm):2.37-2.40(m,1H),2.34-2.37(m,1H),2.16-2.17(m,2H ),1.98-2.05(m,5H),1.65-1.81(m,8H),1.52-1.56(m,1H),1.48-1.51(m,1H).

[0136] (Synthesis Example 3)

[0137] [ka] 1-Chlorodiamantane (1.54 mg, 6.92 mmol) obtained in Synthesis Example 2 was suspended in phenol (5.21 g, 55.3 mmol) and stirred at 120°C for 16 hours. After stirring, the suspension was filtered while hot, and the resulting filter cake was washed with hot water. The resulting solid was purified by silica gel column chromatography (hexane / ethyl acetate = 9:1) to give 4-(1-diamantyl)phenol as a white solid (1.81 g, yield 93%). 1 H-NMR(CDCl3)δ(ppm):7.21(d,J=8.8Hz,2H),6.79(d,J=8.8Hz,2H),4.50(s,1H),2.28-2.30(m,2H),1.96-1 .98(m,2H),1.75-1.89(m,8H),1.63-1.68(m,3H),1.52-1.53(m,2H),1.41-1.45(m,1H),1.38-1.42(m,1H).

[0138] (Synthesis Example 4)

[0139] [ka] Under an argon atmosphere, 4-(1-diamantyl)phenol (1.81 g, 6.45 mmol) obtained in Synthesis Example 3 was suspended in dichloromethane (16 mL) and pyridine (1.53 g, 19.4 mmol) was added. This suspension was cooled to 0°C, and a solution of trifluoromethanesulfonic anhydride (2.73 g, 9.68 mmol) dissolved in dichloromethane (8.0 mL) was added dropwise. After the addition was complete, the mixture was stirred at 0°C for 2 hours, then warmed to room temperature and stirred for 17 hours. After stirring, 1 M aqueous hydrochloric acid and chloroform were added to separate the organic layer. Sodium sulfate was added to the organic layer and allowed to stand. The desiccant was then filtered off, and the filtrate was concentrated under reduced pressure. The resulting liquid was purified by silica gel column chromatography (hexane) to give 4-(1-diamantyl)phenyl trifluoromethanesulfonate as a colorless liquid (2.32 g, 87% yield). 1 H-NMR(CDCl3)δ(ppm):7.41(d,J=9.0Hz,2H),7.20(d,J=9.0Hz,2H),2.30-2.33(m,2H),1.99 -2.01(m,2H),1.88-1.92(m,1H),1.68-1.81(m,10H),1,51-1.52(m,2H),1.43-1.49(m,2H).

[0140] (Synthesis Example 5)

[0141] [ka] Under an argon atmosphere, 4-(1-diamantyl)phenyl triflumethanesulfonate (3.00 g, 7.27 mmol) obtained in Synthesis Example 4, bis-pinacolatodiboron (2.03 g, 8.01 mmol), palladium acetate (0.0327 g, 0.146 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.139 g, 0.291 mol), and potassium acetate (2.14 g, 21.8 mmol) were suspended in tetrahydrofuran (73 mL) and stirred at 70°C for 16 hours. After cooling to room temperature, the precipitate was removed by filtration. The filtrate was concentrated under reduced pressure and dried to obtain a crude product. Methanol was added, the mixture was stirred and suspended, and the solid was collected by filtration. The obtained solid was dried under reduced pressure to obtain 4-(1-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as a gray powder (yield: 2.8 g, 89%). 1 H-NMR(CDCl3)δ(ppm):7.78(d,J=8.3Hz,2H),7.37(d,J=8.3Hz,2H),2.36-2.40(m,2H),1.96-1.99( m,2H),1.87-1.89(m,1H),1.63-1.82(m,10H),1.49-1,53(m,2H),1.40-1.46(m,2H),1.34(s,12H).

[0142] (Synthesis Example 6)

[0143] [ka] 4-Hydroxydiamantane (4.50 g, 22.0 mmol) obtained in Synthesis Example 1 was suspended in thionyl chloride (11.9 mL, 154 mmol) and stirred at room temperature for 1 hour. After stirring, low-boiling components were distilled off under reduced pressure. The resulting solid was purified by silica gel column chromatography (hexane) to obtain 4-chlorodiamantane as a white solid (4.76 g, 97% yield). 1 H-NMR(CDCl3)δ(ppm):2.10-2.11(m,6H),1.94(s,3H),1.77-1.81(m,4H),1.72-1.73(m,6H).

[0144] (Synthesis Example 7)

[0145] [ka] 4-Chlorodiamantane (4.71 g, 21.1 mmol) obtained in Synthesis Example 6 was suspended in phenol (15.9 g, 169 mmol) and stirred at 120°C for 16 hours. After stirring, the suspension was filtered while hot, and the resulting filter cake was washed with hot water. The resulting solid was purified by silica gel column chromatography (hexane / ethyl acetate = 9:1) to obtain 4-(4-diamantyl)phenol as a white solid (1.81 g, yield 93%). 1 H-NMR(CDCl3)δ(ppm):7.21(d,J=8.8Hz,2H),6.78(d,J=8.8Hz,2H),4.45(s ,1H),1.90(s,3H),1.84-1.85(m,6H),1.76-1.77(m,9H),1.51-1.52(m,1H).

[0146] (Synthesis Example 8)

[0147] [ka] Under an argon atmosphere, 4-(4-diamantyl)phenol (2.00 g, 7.10 mmol) obtained in Synthesis Example 7 was suspended in toluene (36 mL) and pyridine (1.69 g, 21.4 mmol) was added. This suspension was cooled to 0°C, and a solution of trifluoromethanesulfonic anhydride (4.02 g, 14.3 mmol) dissolved in toluene (4.0 mL) was added dropwise. After the addition was complete, the mixture was stirred at 0°C for 2 hours, then warmed to room temperature and stirred for 17 hours. After stirring, water was added to separate the organic layer. Sodium sulfate was added to the organic layer and allowed to stand. The desiccant was removed by filtration, and the filtrate was concentrated under reduced pressure. The resulting liquid was purified by silica gel column chromatography (hexane) to obtain 4-(4-diamantyl)phenyl trifluoromethanesulfonate as a colorless liquid (2.30 g, 78% yield). 1H-NMR(CDCl3)δ(ppm):7.44(d,J=8.8Hz,2H),7.19(d,J=8.8Hz,2H),1.93(s,3H),1.84-1.87(m,7H),1,78(d,J=2.8Hz,9H).

[0148] (Synthesis Example 9)

[0149] [ka] 4-(1-diamantyl)phenol (5.00 g, 17.83 mmol) and p-toluenesulfonic acid hydrate (339 mg, 1.78 mmol) were suspended in dichloromethane (90 mL) and stirred at room temperature for 10 minutes. After stirring, N-iodosuccinimide (4.01 g, 17.83 mmol) was added and the mixture was stirred at room temperature for 24 hours. After stirring, saturated aqueous sodium thiosulfate was added and the organic layer was separated. Sodium sulfate was added to the organic layer and the mixture was allowed to stand. The desiccant was then filtered off, and the filtrate was concentrated under reduced pressure. The resulting solid was purified by silica gel column chromatography (hexane / chloroform) to give 2-iodo-4-(1-diamantyl)phenol as a white solid (6.64 g, 92% yield). 1 H-NMR(CDCl3)δ(ppm):7.57(d,J=2.3Hz,1H),7.22(dd,J=8.6,2.3Hz,1H),6.94(d,J=8.6Hz,1H),5.09(s,1H),2.22-2.25(m,2H),1.96-1.98(m,2H) ,1.85-1.89(m,1H),1.82(brs,1H),1.79(brs,2H),1.75-1.77(m,4H),1. 65-1.69(m,3H),1.51-1.52(m,2H),1.43-1.46(m,1H),1.39-1.42(m,1H).

[0150] (Synthesis Example 10)

[0151] [ka] Under an argon atmosphere, 4-(4-diamantyl)phenyl triflumethanesulfonate (6.30 g, 15.3 mmol) obtained in Synthesis Example 8, bis-pinacolatodiboron (4.27 g, 16.8 mmol), palladium acetate (0.0686 g, 0.306 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.291 g, 0.611 mol), and potassium acetate (4.50 g, 45.8 mmol) were suspended in tetrahydrofuran (153 mL) and stirred at 70°C for 2 hours. After cooling to room temperature, the precipitate was removed by filtration. The filtrate was concentrated under reduced pressure and dried to obtain a crude product. Methanol was added, the mixture was stirred and suspended, and the solid was collected by filtration. The obtained solid was dried under reduced pressure to obtain 4-(4-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as a gray powder (yield: 4.5 g, 76%). 1 H-NMR(CDCl3)δ(ppm):7.77(d,J=8.4Hz,2H),7.40(d,J=8.4Hz,2H),1.88-1.91(m,9H),1.77-1.78(m,10H),1.33(s,12H).

[0152] (Synthesis Example 1)

[0153] [ka] Under an argon atmosphere, 2-chloro-4,6-diphenyl-1,3,5-triazine (1.50 g, 15.6 mmol), 4-(1-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.41 g, 6.16 mmol) obtained in Synthesis Example 5, and tetrakis(triphenylphosphine)palladium (0.194 g, 0.168 mmol) were dissolved in THF (56.0 mL). To this solution was added 2 M aqueous potassium phosphate solution (8.40 mL, 16.8 mmol) and stirred at 70 °C for 20 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. The collected material was suspended in toluene (300 mL), heated to 110 °C, added with activated carbon, and stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-6) as a white solid (2.20 g, yield 80%). The glass transition temperature was 92°C. 1 H-NMR(CDCl3)δ(ppm):8.77-8.79(m,4H),8.71(brd,J=8.8Hz,2H),7.55-7.63(m,8H),2.46(s,2H), 2.03(s,2H),1.79-1.96(m,8H),1.67-1.72(m,3H),1.62(d,J=2.4Hz,2H),1.51(s,1H),1.47(s,1H).

[0154] (Synthesis Example 2)

[0155] [ka] Under an argon atmosphere, 2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (2.00 g, 4.59 mmol), 4-(1-diamantyl)phenyl triflumethanesulfonate (2.08 g, 5.05 mmol) obtained in Synthesis Example 4, and tetrakis(triphenylphosphine)palladium (0.106 g, 0.092 mmol) were dissolved in THF (45.9 mL). To this solution was added 2 M aqueous potassium phosphate (6.90 mL, 13.8 mmol) and stirred at 70 °C for 20 hours. After cooling to room temperature, the precipitated solid was collected by filtration. The collected material was suspended in toluene (300 mL), heated to 100 °C, added with activated carbon, and stirred. The mixture was then filtered through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-27) as a white solid (2.2 g, yield 84%). The glass transition temperature was 131°C. 1 H-NMR(CDCl3)δ(ppm):8.84(brd,J=8.0Hz,2H),8.79-8.82(m,4H),7.83(brd,J=8.4Hz,2H),7.69(brd,J=8.0Hz,2H),7.57-7.65(m,6H),7.49(brd,J= 8.4Hz,2H),2.43(s,2H),2.03(s,2H),1.89-1.94(m,3H),1.77-1.85(m,5H) ,1.71(brd,J=1.6Hz,3H),1.62(d,J=2.8Hz,2H),1.51(s,1H),1.47(s,1H).

[0156] (Synthesis Example 3)

[0157] [ka] Under an argon atmosphere, 2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (2.00 g, 4.59 mmol), 4-(4-diamantyl)phenyl triflumethanesulfonate (2.08 g, 5.05 mmol) obtained in Synthesis Example 8, and tetrakis(triphenylphosphine)palladium (0.106 g, 0.092 mmol) were dissolved in THF (45.9 mL). To this solution was added 2 M aqueous potassium phosphate (6.90 mL, 13.8 mmol) and stirred at 70 °C for 20 hours. After cooling to room temperature, the precipitated solid was collected by filtration. The collected material was suspended in toluene (100 mL), heated to 100 °C, added activated carbon, and stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-87) as a white solid (2.0 g, yield 75%). The glass transition temperature was 138°C. 1 H-NMR(CDCl3)δ(ppm):8.84(brd,J=8.4Hz,2H),8.79-8.81(m,4H),7.81(brd,J=8.4Hz,2H),7.68 (brd,J=8.4Hz,2H),7.57-7.65(m,6H),7.52(brd,J=8.4Hz,2H),1.95(s,9H),1.77-1.85(m,10H).

[0158] (Synthesis Example 4)

[0159] [ka] Under an argon atmosphere, 4-(3-fluoranthenyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.75 g, 4.33 mmol), 4-(1-diamantyl)phenyl triflumethanesulfonate (1.70 g, 4.12 mmol) obtained in Synthesis Example 4, and tetrakis(triphenylphosphine)palladium (0.143 g, 0.124 mmol) were dissolved in THF (41.2 mL). To this solution was added 2 M aqueous potassium phosphate (6.18 mL, 12.4 mmol) and stirred at 70 °C for 4 hours. After cooling to room temperature, the precipitated solid was collected by filtration. The collected material was suspended in toluene (600 mL), heated to 100 °C, added with activated carbon, and stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-19) as a white solid (0.89 g, yield 40%). The glass transition temperature was 131°C. 1 H-NMR(CDCl3)δ(ppm):8.03(s,1H),8.01(s,1H),7.99(d,J=7.2Hz,1H),7. 92-7.96(m,2H),7.75-7.79(m,2H),7.63-7.69(m,6H),7.48(d,J=8.4Hz,2 H),7.38-7.42(m,2H),2.43(s,2H),2.02(s,2H),1.91-1.97(m,3H),1.78- 1.86(m,5H),1.72(s,3H),1.63(d,J=1.2Hz,2H),1.51(s,1H),1.47(s,1H).

[0160] (Synthesis Example 5)

[0161] [ka]

[0162] [ka] Under an argon atmosphere, 4,6-diphenyl-2-[3'-chloro-1,1':6',1''-terphenyl-3-yl]-1,3,5-triazine (1.50 g, 3.02 mmol), bis(neopentylglycolato)diboron (0.890 g, 3.93 mmol), palladium acetate (33.9 mg, 0.160 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.140 g, 0.300 mmol), and potassium acetate (0.890 g, 9.07 mmol) were suspended in THF (30 mL) and stirred at 80 °C for 16 hours. After cooling to room temperature, chloroform, water, and saturated brine were added, and the organic layer was separated. Sodium sulfate was added to the organic layer and allowed to stand. The desiccant was then removed by filtration, and the filtrate was concentrated under reduced pressure. The resulting solid was dissolved in chloroform, activated carbon was added, and the mixture was filtered through Celite. The filtrate was concentrated and washed with hexane to give 4,6-diphenyl-2-[3'-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)-1,1':6',1''-terphenyl-3-yl]-1,3,5-triazine as a white solid (1.50 g, 86% yield). 1 H-NMR(CDCl3)δ(ppm):8.71-8.75(m,4H),8.62(s,1H),8.59-8.62(m,1H),8.00(d,J=0.8Hz,1H),7.92(dd,J=7.6,0. 8Hz,1H),7.55-7.64(m,7H),7.51(d,J=7.6Hz,1H),7.39-7.40(m,2H),7.13-7.26(m,4H),3.81(s,4H),1.06(s,6H).

[0163] Under an argon atmosphere, 4,6-diphenyl-2-[3'-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)-1,1':6',1''-terphenyl-3-yl]-1,3,5-triazine (1.50 g, 2.61 mmol), 4-(1-diamantyl)phenyl trifluoromethanesulfonate (1.29 g, 3.13 mmol) obtained in Synthesis Example 4, palladium acetate (12 mg, 0.05 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (49.6 mg, 0.10 mmol) were dissolved in THF (26 mL). A 2M aqueous potassium carbonate solution (1.3 mL, 2.6 mmol) was added to the solution, and the mixture was stirred at 80°C for 16 hours. After allowing the mixture to cool to room temperature, water and methanol were added to the reaction mixture, and the precipitated solid was collected by filtration. The filtered material was dissolved in chloroform, stirred with activated carbon, and then filtered through Celite. The filtrate was concentrated and purified by recrystallization from toluene to obtain compound (1-54) as a white solid (1.50 g, yield 79%). The glass transition temperature was 148°C. 1 H-NMR(CDCl3)δ(ppm):8.72-8.75(m,4H),8.68-8.69(m,1H),8.64-8.66(m,1H),7.82(d,J=1.8Hz ,1H),7.74(dd,J=8.0,1.8Hz,1H),7.68(d,J=8.3Hz,2H),7.55-7.64(m,7H),7.46(d,J=8.3Hz,2H ),7.40-7.43(m,2H),7.23-7.31(m,4H),7.15-7.19(m,1H),2.39-2.42(m,2H),1.99-2.04(m,2H) ,1.88-1.93(m,3H),1.76-1.85(m,5H),1.68-1.71(m,3H),1.60-1.62(m,2H),1.44-1.49(m,2H).

[0164] (Synthesis Example 6)

[0165] [ka] Under an argon atmosphere, 2-chloro-4,6-bisbiphenylyl-1,3,5-triazine (2.00 g, 4.76 mmol), 4-(1-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.23 g, 5.72 mmol) obtained in Synthesis Example 5, and tetrakis(triphenylphosphine)palladium (0.550 g, 0.476 mmol) were dissolved in THF (48 mL). To this solution was added 2 M aqueous potassium carbonate (7.10 mL, 14.3 mmol) and stirred at 80 °C for 15 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. The collected material was suspended in chloroform, heated to 110 °C, added with activated carbon, and stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-8) as a white solid (1.88 g, yield 61%). The glass transition temperature was 147°C. 1 H-NMR(CDCl3)δ(ppm):8.87(d,J=8.6Hz,4H),8.74(d,J=8.6Hz,2H),7.82(d,J=8 .6Hz,4H),7.71-7.74(m,4H),7.60(d,J=8.6Hz,2H),7.49-7.53(m,4H),7.40-7.4 4(m,2H),2.45-2.49(m,2H),2.02-2.06(m,2H),1.93-1.97(m,1H)1.79-1.91(m, 7H),1.68-1.74(m,3H),1.63-1.64(m,2H),1.52-1.55(m,1H),1.47-1.50(m,1H).

[0166] (Synthesis Example 7)

[0167] [ka] Under an argon atmosphere, 2-chloro-4-biphenylyl-6-phenyl-1,3,5-triazine (2.00 g, 5.82 mmol), 4-(1-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.73 g, 6.98 mmol), and tetrakis(triphenylphosphine)palladium (0.336 g, 0.291 mmol) were dissolved in tetrahydrofuran (58 mL). To this solution was added 2 M aqueous potassium carbonate (8.70 mL, 17.45 mmol) and stirred at 80 °C for 15 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. The collected material was dissolved in chloroform, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-9) as a white solid (1.69 g, 51% yield). The glass transition temperature was 118°C. 1 H-NMR(CDCl3)δ(ppm):8.85(d,J=8.6Hz,2H),8.79-8.81(m,2H),8.73(d,J=8.6Hz,2 H),7.8(d,J=8.6Hz,2H),7.70-7.73(m,2H),7.57-7.62(m,5H),7.48-7.53(m,2H),7. 40-7.44(m,1H),2.44-2.49(m,2H),2.02-2.06(m,2H),1.93-1.96(m,1H),1.78-1.90 (m,7H),1.68-1.71(m,3H),1.63-1.64(m,2H),1.51-1.53(m,1H),1.48-1.50(m,1H).

[0168] (Synthesis Example 8)

[0169] [ka]

[0170] [ka]

[0171] [ka] Under an argon atmosphere, 2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (3.86 g, 8.86 mmol), 2-iodo-4-(1-diamantyl)phenol (3.00 g, 7.38 mmol), palladium acetate (83 mg, 0.37 mmol), and tricyclohexylphosphine (124 mg, 0.44 mmol) were dissolved in tetrahydrofuran (73.8 mL). To this solution was added 2 M aqueous potassium carbonate (11.1 mL, 22.15 mmol) and stirred at 80 °C for 16 hours. After cooling to room temperature, water was added and the organic layer was separated. Sodium sulfate was added to the organic layer, and the mixture was allowed to stand. The drying agent was removed by filtration, and the filtrate was concentrated under reduced pressure. The residue was dissolved in chloroform (250 mL), activated carbon was added, and the mixture was stirred and then filtered through Celite. The filtrate was concentrated, and the resulting solid was purified by silica gel column chromatography (hexane / chloroform) to give a white solid of 4,6-diphenyl-2-[2'-hydroxy-4'-(1-diamantyl)-1,1'-biphenyl-4-yl]-1,3,5-triazine (2.0 g, yield 75%). The glass transition temperature was 147°C. 1 H-NMR(CDCl3)δ(ppm):8.89(d,J=8.5Hz,2H),8.79-8.81(m,4H),7.73(d,J=8. 5Hz,2H),7.57-7.66(m,6H),7.28-7.31(m,2H),6.98(d,J=8.3Hz,1H),5.07(br s,1H),2.34-2.37(m,2H),1.98-2.02(m,2H),1.95(brs,1H),1.90-1.92(m,2H ),1.75-1.83(m,5H),1.68-1.72(m,3H),1.61-1.62(m,2H),1.44-1.49(m,2H).

[0172] Under an argon atmosphere, 4,6-diphenyl-2-[2'-hydroxy-4'-(4-diamantyl)-1,1'-biphenyl-4-yl]-1,3,5-triazine (2.86 g, 4.86 mmol) was suspended in 24.3 mL of dichloromethane, and pyridine (1.54 g, 19.43 mmol) was added. This suspension was cooled to 0°C, and trifluoromethanesulfonic anhydride (2.74 g, 9.71 mmol) was added dropwise. After the dropwise addition was completed, the mixture was stirred at 0°C for 2 hours, then warmed to room temperature and stirred for 17 hours. After stirring, water was added and the organic layer was separated. Sodium sulfate was added to the organic layer, and the mixture was allowed to stand. The drying agent was then filtered off, and the filtrate was concentrated under reduced pressure. The resulting liquid was purified by silica gel column chromatography (hexane) to give a white solid of 4,6-diphenyl-2-[2'-trifulmethanesulfonate-4'-(1-diamantyl)-1,1'-biphenyl-4-yl]-1,3,5-triazine (3.09 g, yield 88%). 1 H-NMR(CDCl3)δ(ppm):8.88(d,J=8.4Hz,2H),8.79-8.81(m,4H),7.69(d,J=8. 4Hz,2H),7.57-7.66(m,6H),7.50(d,J=2.4Hz,1H),7.45(dd,J=8.6,2.4Hz,1H) ,7.37(d,J=8.6Hz,1H),2.37-2.40(m,2H),2.00-2.04(m,2H),1.92-1.96(m,1H ),1.80-1.84(m,6H),1.70-1.74(m,3H),1.61-1.62(m,2H),1.48-1.52(m,2H).

[0173] Under an argon atmosphere, 4,6-diphenyl-2-[2'-triflumethanesulfonato-4'-(1-diamantyl)-1,1'-biphenyl-4-yl]-1,3,5-triazine (2.89 g, 4.01 mmol), phenylboronic acid (1.96 g, 16.06 mmol), and tetrakis(triphenylphosphine)palladium (0.928 g, 0.80 mmol) were dissolved in tetrahydrofuran (12 mL). To this solution was added 2 M aqueous potassium carbonate (12.05 mL, 24.09 mmol) and stirred at 80 °C for 15 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. The collected material was dissolved in chloroform, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-103) as a white solid (1.77 g, 68% yield). 1 H-NMR(CDCl3)δ(ppm):8.75-8.78(m,4H),8.65(d,J=8.6Hz,2H),7.55-7.63( m,6H),7.47(brs,1H),7.43-7.45(m,2H),7.38(d,J=8.6Hz,2H),7.22(brs,5 H),2.44-2.47(m,2H),2.00-2.03(m,3H),1.98(brs,1H),1.93-1.95(m,1H), 1.77-1.86(m,5H),1.72-1.75(m,3H),1.68-1.69(m,2H),1.48-1.54(m,2H).

[0174] (Synthesis Example 9)

[0175] [ka] Under an argon atmosphere, 2-[1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolane)phenyl-3-yl]-4-(1,1'-biphenyl-2-yl)-6-biphenylyl-1,3,5-triazine (2.22 g, 3.78 mmol), 4-(1-diamantyl)phenyl trifluoromethanesulfonate (1.30 g, 3.15 mmol), palladium acetate (0.035 g, 0.158 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (150.2 mg, 0.315 mmol) were dissolved in tetrahydrofuran (32 mL). 2 M aqueous potassium phosphate solution (4.73 mL, 9.46 mmol) was added and stirred at 80 °C for 15 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. The filtered material was dissolved in chloroform, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization with toluene to obtain compound (1-104) as a white solid (1.64 g, yield 72%). The glass transition temperature was 125°C. 1 H-NMR(CDCl3)δ(ppm):8.60(t,J=1.7Hz,1H),8.41(d,J=8.5Hz,2H),8.36(dd,J=7.3,1. 7Hz,1H),8.31-8.33(m,1H),7.77-7.80(m,1H),7.67-7.70(m,4H),7.47-7.65(m,10H), 7.38-7.43(m,1H),7.35-7.38(m,2H),7.29-7.33(m,2H),7.18-7.23(m,1H),2.43-2.46(m,2H),2.01-2.05(m,2H), 1.92-1.95(m,3H),1.78-1.87(m,5H),1.70-1.74(m,3H),1.64-1.65(m,2H),1.51-1.53(m,1H),1.48-1.50(m,1H).

[0176] (Synthesis Example 10)

[0177] [ka] Under an argon atmosphere, 4-(4-diamantyl)phenyl trifluoromethanesulfonate (1.78 g, 4.30 mmol), bis(4-biphenylyl)amine (1.66 g, 5.16 mmol), trisdibenzylideneacetonedipalladium (118 mg, 0.13 mol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (106 mg, 0.26 mmol), and sodium tert-butoxide (620 mg, 6.45 mmol) were suspended in xylene (17 mL) and stirred at 140 °C for 40 h. After cooling to room temperature, toluene was added to the reaction mixture and the mixture was filtered through Celite. The solvent was evaporated, and the resulting crude product was purified by silica gel column chromatography (hexane / chloroform) to give compound (1-106) as a white powder (1.61 g, 64% yield). The glass transition temperature was 104 °C. 1 H-NMR(CDCl3)δ(ppm):7.57-7.60(m,4H),7.50(d,J=8.4Hz,4H),7.40-7.44 (m,4H),7.28-7.33(m,2H),7.25(d,J=8.4Hz,2H),7.19(d,J=8.4Hz,4H),7.1 2(d,J=8.4Hz,2H),2.30-7.35(m,2H),1.97-2.01(m,2H),1.88-1.95(m,3H), 1.76-1.83(m,5H),1.69-1.72(m,3H),1.59-1.60(m,2H),1.42-1.48(m,2H).

[0178] (Synthesis Example 11)

[0179] [ka] Under an argon atmosphere, 4-(4-diamantyl)phenyl trifluoromethanesulfonate (2.06 g, 5.00 mmol), 2-(1,1'-biphenyl-4-yl)amino-9,9-dimethylfluorene (2.17 g, 6.00 mmol), trisdibenzylideneacetonedipalladium (137 mg, 0.15 mol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (123 mg, 0.30 mmol), and sodium tert-butoxide (721 mg, 7.50 mmol) were suspended in xylene (20 mL) and stirred at 140 °C for 40 h. After cooling to room temperature, toluene was added to the reaction mixture and the mixture was filtered through Celite. The solvent was evaporated, and the resulting crude product was purified by silica gel column chromatography (hexane / chloroform) to give compound (1-113) as a white powder (1.94 g, 61% yield). The glass transition temperature was 116°C. 1 H-NMR(CDCl3)δ(ppm):7.64(d,J=7.6Hz,1H),7.58-7.60(m,3H),7.49(d,J=8.6Hz,2H ),7.38-7.44(m,3H),7.29-7.34(m,2H),7.22-7.28(m,4H),7.19(d,J=8.6Hz,2H),7.1 2(d,J=8.4Hz,2H),7.06-7.09(m,1H),2.30-2.34(m,2H),1.96-2.00(m,2H),1.88-1.9 5(m,3H),1.74-1.83(m,5H),1.69-1.72(m,3H),1.59-1.60(m,2H),1.42-1.47(m,8H).

[0180] (Synthesis Example 12)

[0181] [ka] Under an argon atmosphere, N,N-bis(1,1'-biphenyl-4-yl)-N-(4-bromophenyl)amine (2.37 g, 4.96 mmol), 4-(1-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.13 g, 5.46 mmol), and tetrakis(triphenylphosphine)palladium (0.287 g, 0.248 mmol) were dissolved in 1,4-dioxane (50 mL). To this solution was added 2 M aqueous potassium carbonate (7.44 mL, 14.88 mmol), and the mixture was stirred at 110 °C for 18 hours. After stirring, water was added to separate the organic layer. Sodium sulfate was added to the organic layer, and the mixture was allowed to stand. The desiccant was removed by filtration, and the filtrate was concentrated under reduced pressure. The resulting solid was dissolved in chloroform, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-108) as a white solid (2.65 g, yield 81%). The glass transition temperature was 129°C. 1 H-NMR(CDCl3)δ(ppm):7.51-7.61(m,12H),7.41-7.45(m,6H),7.30-7.34(m,2H),7.22-7.25(m,6H),2.38-2.41(m,2H) ),1.99-2.02(m,2H),1.86-1.93(m,3H),1.76-1.85(m,5H),1.67-1.71(m,3H),1.59-1.60(m,2H),1.45-1.48(m,2H).

[0182] (Synthesis Example 13)

[0183] [ka] Under an argon atmosphere, 4-(4-diamantyl)phenyl trifluoromethanesulfonate (2.06 g, 5.00 mmol), N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9-diphenyl-9H-fluoren-2-amine (3.15 g, 6.00 mmol), trisdibenzylideneacetonedipalladium (137 mg, 0.15 mol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (123 mg, 0.30 mmol), and sodium tert-butoxide (721 mg, 7.50 mmol) were suspended in xylene (20 mL) and stirred at 140 °C for 40 h. After cooling to room temperature, the reaction mixture was added with toluene and filtered through Celite. The solvent was removed by distillation, and the resulting crude product was purified by silica gel column chromatography (hexane / chloroform) to give compound (1-117) as a white powder (2.69 g, yield 68%). The glass transition temperature was 151°C. 1 H-NMR(CDCl3)δ(ppm):7.66-7.68(m,1H),7.60-7.62(m,2H),7.52(d,J=8.3Hz,1H),7.36 -7.38(m,1H),7.27-7.33(m,3H),7.21-7.24(m,2H),7.12-7.21(m,14H),7.09(dd,J=8.3, 2.0Hz,1H),6.97-7.01(m,3H),2.28-2.31(m,2H),1.96-1.99(m,2H),1.85-1.91(m,3H), 1.74-1.82(m,5H),1.68-1.71(m,3H),1.57-1.58(m,2H),1.41-1.46(m,2H),1.35(s,6H).

[0184] (Synthesis Example 14)

[0185] [ka] Under an argon atmosphere, 4-(4-diamantyl)phenyl triflumethanesulfonate (2.06 g, 5.00 mmol), 3-[4-(4-biphenylylamino)phenyl]-9-phenylcarbazole (2.92 g, 6.00 mmol), trisdibenzylideneacetonedipalladium (137 mg, 0.15 mol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (123 mg, 0.30 mmol), and sodium tert-butoxide (721 mg, 7.50 mmol) were suspended in xylene (20 mL) and stirred at 140 °C for 40 hours. After cooling to room temperature, toluene was added to the reaction mixture, which was then filtered through Celite. The solvent was removed by distillation, and the resulting crude product was purified by silica gel column chromatography (hexane / chloroform) to give compound (1-118) as a white powder (2.52 g, 67% yield). The glass transition temperature was 144°C. 1 H-NMR(CDCl3)δ(ppm):8.34(s,1H),8.18(d,J=7.7Hz,1H),7.57-7.67(m,10H),7.47-7.52(m,4H),7.39-7.46(m,5H),7.20-7.34(m,4H),7.14-7. 19(m,4H),2.32-2.35(m,2H),1.97-2.00(m,2H),1.89-1.96(m,3H),1.7 7-1.83(m,5H),1.69-1.72(m,3H),1.60-1.61(m,2H),1.43-1.49(m,2H).

[0186] (Synthesis Example 15)

[0187] [ka]

[0188] [ka]

[0189] [ka]

[0190] [ka]

[0191] [ka] Under an argon atmosphere, Congresane (4.16 g, 22.07 mmol) and aluminum bromide (0.46 g, 1.72 mmol) were suspended in heptane (22.0 mL). To the suspension cooled to -10 °C, a solution of bromine (17.99 g, 112.56 mmol) in heptane (10.4 mL) was added dropwise over 2 hours. After the addition, the mixture was warmed to 0 °C and stirred for 1 hour. After that, the mixture was transferred to an ice bath using carbon tetrachloride (24 mL) and sodium bicarbonate was added. Water and dichloromethane were added, and the organic layer was separated. Sodium sulfate was added to the organic layer, and the mixture was allowed to stand. The desiccant was then filtered off, and the filtrate was concentrated under reduced pressure. The resulting solid was purified by recrystallization from acetone to give 3,7-dibromodiamantane as a white solid (3.07 g, 40% yield). 1 H-NMR(CDCl3)δ(ppm):2.32(brs,12H),1.97(brs,6H).

[0192] 3,7-Dibromodiamantane (3.01 g, 8.70 mmol) was suspended in phenol (8.18 g, 86.97 mmol) and stirred at 120°C for 116 hours. After stirring, the suspension was filtered while hot, and the resulting filter cake was washed with hot water. The resulting solid was purified by recrystallization from methanol to give 3,7-di(1-hydroxyphenyl-4-yl)diamantane as a white solid (3.09 g, 95% yield). 1 H-NMR(DMSO-d6)δ(ppm):7.17(d,J=8.6Hz,4H),6.69(d,J=8.6Hz,4H),1.88(brs,6H),1.83(brs,12H).

[0193] Under an argon atmosphere, 3,7-di(1-hydroxyphenyl-4-yl)diamantane (3.09 g, 8.28 mmol) was suspended in methylene chloride (41.4 mL). Pyridine (5.24 g, 66.25 mmol) was added to this suspension, which was then cooled to 0°C. Trifluoromethanesulfonic anhydride (9.35 g, 33.13 mmol) was added dropwise and stirred for 4 hours. After confirming the disappearance of the starting materials by TLC, the mixture was quenched with hydrochloric acid and extracted with chloroform. The resulting organic layer was washed with saturated aqueous sodium bicarbonate, dried over sodium sulfate, and the solvent was evaporated. The resulting crude product was purified by silica gel column chromatography (hexane / ethyl acetate) to give 3,7-di(1-trifluoromethanesulfonylphenyl-4-yl)diamantane as a white solid (4.91 g, 93% yield). 1 H-NMR(CDCl3)δ(ppm):7.46(d,J=8.9Hz,4H),7.22(d,J=8.9Hz,4H),1.99(brs,6H),1.95(brs,12H).

[0194] Under an argon atmosphere, 3,7-di(1-trifluoromethanesulfonylphenyl-4-yl)diamantane (2.00 g, 3.14 mmol), bis-pinacolatodiboron (1.91 g, 7.54 mmol), palladium acetate (0.07 g, 0.31 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.30 g, 0.63 mol), and potassium acetate (1.85 g, 18.85 mmol) were suspended in tetrahydrofuran (31 mL) and stirred at 80 °C for 16 hours. After cooling to room temperature, water was added and the organic layer was separated. Sodium sulfate was added to the organic layer and the mixture was allowed to stand. The desiccant was removed by filtration, and the filtrate was concentrated under reduced pressure. The resulting solid was dissolved in chloroform, activated carbon was added, and the mixture was stirred and then filtered through Celite. The filtrate was concentrated, and the resulting solid was purified by recrystallization from toluene to give 3,7-di[1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl-4-yl]diamantane as a white solid (1.21 g, yield 65%). 1H-NMR(CDCl3)δ(ppm):7.79(d,J=8.3Hz,4H),7.43(d,J=8.3Hz,4H),1.96-1.98(m,18H),1.34(s,24H).

[0195] Under an argon atmosphere, 2-chloro-4,6-diphenylyl-1,3,5-triazine (62 mg, 0.23 mmol), 3,7-di[1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl-4-yl]diamantane (58 mg, 0.10 mmol), and tetrakis(triphenylphosphine)palladium (11 mg, 0.01 mmol) were dissolved in tetrahydrofuran (1 mL). 5 M aqueous sodium hydroxide solution (0.12 mL, 0.58 mmol) was added and stirred at 80 °C for 15 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. The collected material was dissolved in hot chlorobenzene, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from chlorobenzene to give compound (1-100) as a white solid (38 mg, 49% yield). No glass transition temperature was detected. 1 H-NMR(CDCl3)δ(ppm):8.78-8.80(m,8H),8.74(d,J=8.5Hz,4H),7.57-7.65(m.16H),2.08-2.10(m,18H).

[0196] (Synthesis Example 16)

[0197] [ka] Under an argon atmosphere, 4-(1-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (100 mg, 0.26 mmol), 9-bromo-10-phenylanthracene (102 mg, 0.31 mmol), and tetrakis(triphenylphosphine)palladium (9 mg, 0.01 mmol) were dissolved in tetrahydrofuran (2.6 mL). 5 M aqueous sodium hydroxide solution (0.15 mL, 0.77 mmol) was added and stirred at 80 °C for 15 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. The collected material was dissolved in hot toluene, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-122) as a white solid (112 mg, 84% yield). The glass transition temperature was 140 °C. 1 H-NMR(CDCl3)δ(ppm):7.75-7.78(m,2H),7.67-7.70(m,2H),7.55-7.62(m,5H),7.48-7.50(m,2H),7.42(d,J=8.4Hz,2H),7.30- 7.36(m,4H),2.49-2.51(m,2H),2.06-2.09(m,4H),1.97-2.00(m,1H),1.79-1.89(m,6H),1.75-1.77(m,4H),1.53-1.58(m,1H).

[0198] (Synthesis Example 17)

[0199] [ka]

[0200] [ka]

[0201] [ka] Under an argon atmosphere, 2-bromodibenzofuran (200 mg, 0.81 mmol), anthracene-9-boronic acid (216 mg, 0.97 mmol), and tetrakis(triphenylphosphine)palladium (47 mg, 0.04 mmol) were dissolved in tetrahydrofuran (8.1 mL). To this solution was added 2M aqueous potassium carbonate (1.21 mL, 2.43 mmol), and the mixture was stirred at 80 °C for 15 hours. After cooling to room temperature, water was added and the organic layer was separated. Sodium sulfate was added to the organic layer, and the mixture was allowed to stand. The desiccant was removed by filtration, and the filtrate was concentrated under reduced pressure. The resulting crude product was purified by silica gel column chromatography (hexane / toluene) to give 2-(9-anthracene)dibenzofuran as a yellow solid (223 mg, 80% yield). 1 H-NMR(CDCl3)δ(ppm):8.54(s,1H),8.06-8.09(m,2H),8.02-8.03(m,1H),7.92-7.93(m,1 H),7.78(dd,J=8.8,0.5Hz,1H),7.67-7.70(m,3H),7.46-7.54(m,4H),7.33-7.38(m,3H).

[0202] Under an argon atmosphere, 2-(9-anthracene)dibenzofuran (100 mg, 0.29 mmol) was dissolved in dimethylformamide (1.0 mL). A solution of N-bromosuccinimide (52 mg, 0.29 mmol) in dimethylformamide (1.3 mL) was added dropwise to the reaction mixture and stirred at 60 °C for 3 hours. After cooling to room temperature, water was added and the organic layer was separated. Sodium sulfate was added to the organic layer and the mixture was allowed to stand. The desiccant was then filtered off, and the filtrate was concentrated under reduced pressure. The resulting crude product was purified by silica gel column chromatography (hexane / toluene) to give 2-(10-bromoanthracen-9-yl)dibenzofuran as a yellow solid (108 mg, 88% yield). 1H-NMR(CDCl3)δ(ppm):8.63-8.66(m,2H),8.00(dd,J=1.7,0.5Hz,1H),7.91-7.93(m,1H),7.78(dd,J=8.3,0.5Hz ,1H),7.66-7.69(m,3H),7.59-7.63(m,2H),,7.50-7.55(m,1H),7.48(dd,J=8.3,1.7Hz,1H),7.34-7,40(m,3H).

[0203] Under an argon atmosphere, 4-(1-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (70 mg, 0.18 mmol), 2-(10-bromoanthracen-9-yl)dibenzofuran (91 mg, 0.22 mmol), and tetrakistriphenylphosphinopalladium (6.2 mg, 0.01 mmol) were suspended in tetrahydrofuran (1.8 mL). 5 M aqueous sodium hydroxide solution (0.11 mL, 0.54 mmol) was added to the suspension and stirred at 80 °C for 16 hours. After cooling to room temperature, water was added to separate the organic layer. Sodium sulfate was added to the organic layer and the mixture was allowed to stand. The desiccant was removed by filtration, and the filtrate was concentrated under reduced pressure. The resulting crude product was purified by silica gel column chromatography (hexane / toluene) to give compound (1-125) as a yellow solid (98 mg, 90% yield). The glass transition temperature was 152 °C. 1 H-NMR(CDCl3)δ(ppm):8.07-8.08(m,1H),7.92-7.94(m,1H),7.78-7.81(m,3 H),7.70-7.72(m,2H),7.67-7.69(m,1H),7.56-7.60(m,3H),7.50-7.54(m,1H ),7.43-7.46(m,2H),7.30-7.39(m,5H),2.50-2.53(m,2H),2.05-2.11(m,4H) ,1.98-2.01(m,1H),1.80-1.90(m,6H),1.77-1.78(m,4H),1.54-1.59(m,1H).

[0204] (Synthesis Example 18)

[0205] [ka] Under an argon atmosphere, 4-(1-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (100 mg, 0.26 mmol), 2-bromo-9,10-di(1-naphthyl)anthracene (157 mg, 0.31 mmol), and tetrakis(triphenylphosphine)palladium (9 mg, 0.01 mmol) were dissolved in tetrahydrofuran (2.6 mL). 5 M aqueous sodium hydroxide solution (0.15 mL, 0.77 mmol) was added and stirred at 80 °C for 15 hours. After cooling to room temperature, methanol was added, and the precipitated solid was collected by filtration. The collected material was dissolved in hot toluene, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-128) as a white solid (148 mg, 83% yield). No glass transition temperature was detected. 1 H-NMR(CDCl3)δ(ppm):8.11(d,J=8.2Hz,2H),8.03-8.06(m,4H),7.93-7.96(m,3H),7 .81(d,J=9.1Hz,1H),7.66-7.76(m,4H),7.60-7.64(m,5H),7.47(d,J=8.6Hz,2H),7. 29-7.33(m,4H),2.29-2.32(m,2H),1.94-1.97(m,2H),1.83-1.87(m,1H),1.81-1.83 (m,1H),1.73-1.80(m,6H),1.60-1.66(m,3H),1.50-1.51(m,2H),1.37-1.42(m,2H).

[0206] (Synthesis Example 19)

[0207] [ka] Under an argon atmosphere, 2,4-bis([1,1'-biphenyl]-4-yl)-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine (2.00 g, 3.40 mmol), 4-(1-diamantyl)phenyl triflumethanesulfonate (1.68 g, 4.08 mmol), palladium acetate (38 mg, 0.17 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.16 g, 0.34 mol) were suspended in tetrahydrofuran (34 mL). To this suspension was added 2 M aqueous potassium carbonate (5.1 mL, 10.21 mmol), and the mixture was stirred at 80 °C for 15 hours. After cooling to room temperature, water and methanol were added, and the precipitated solid was collected by filtration. The filtered material was dissolved in chlorobenzene, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization with toluene to give compound (1-28) as a white solid (yield: 2.20 g, 89%). The glass transition temperature was 166 °C. 1 H-NMR(CDCl3)δ(ppm):8.86-8.89(m,6H),7.85(d,J=8.0Hz,2H),7.83(d,J =8.4Hz,4H),7.72-7.74(m,4H),7.70(d,J=8.4Hz,2H),7.48-7.53(m,6H),7 .47.45(m,2H),2.41-2.45(m,2H),2.01-2.04(m,2H),1.89-1.93(m,3H),1 .78-1.85(m,5H),1.70-1.73(m,3H),1.61-1.63(m,2H),1.57-1.52(m,2H).

[0208] (Synthesis Example 20)

[0209] [ka] Under an argon atmosphere, 5-(8-chloro-fluoranthene-3-yl)-2-phenyl-pyridine (1.00 g, 2.56 mmol), 4-(4-diamantyl)phenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.20 g, 5.64 mmol), palladium acetate (5.76 mg, 0.256 mmol), and tricyclohexylphosphine (24.5 mg, 0.513 mmol) were dissolved in tetrahydrofuran (26 mL). To this solution was added 2 M aqueous potassium phosphate (3.85 mL, 7.69 mmol) and stirred at 70 °C for 5 hours. After cooling to room temperature, the precipitated solid was collected by filtration. The collected material was dissolved in hot toluene, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give compound (1-130) as a white solid (1.52 g, yield 96%). The glass transition temperature was 163°C. 1 H-NMR(CDCl3)δ(ppm):8.18(d,J=2.4Hz,1H),8.13(d,J=1.2Hz,1H),8.11(brs,1H),8.08(d,J=7.2Hz,1H),8.01-8.02(m,1H),8.00(s,1H) ,7.97(d,J=9.6Hz,1H),7.93(d,J=2.8Hz,1H),7.64-7.72(m,6H),7.52-7.56(m,5H),1.95-1.98(m,10H),1.92(s,1H),1.78-1.82(m,9H).

[0210] (Synthesis Example 21)

[0211] [ka] Under an argon atmosphere, 2,4-bis([1,1'-biphenyl]-4-yl)-6-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine (1.78 g, 3.18 mmol), 4-(1-diamantyl)phenyl triflumethanesulfonate (1.58 g, 3.82 mmol), and tetrakis(triphenylphosphine)palladium (308 mg, 0.32 mol) were suspended in tetrahydrofuran (30 mL). 2 M aqueous potassium phosphate solution (4.8 mL, 9.54 mmol) was added to the suspension and stirred at 80 °C for 15 hours. After cooling to room temperature, water and methanol were added, and the precipitated solid was collected by filtration. The collected material was dissolved in hot toluene, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to obtain compound (1-134) as a white solid (yield: 1.40 g, 61%). The glass transition temperature was 148°C. 1 H-NMR(CDCl3)δ(ppm):9.05(t,J=1.6Hz,1H),8.88(d,J=8.6Hz,4H),8.77(dt,J=7.7,1. 6Hz,1H),7.86-7.89(m,1H),7.83(d,J=8.6Hz,4H),7.72-7.76(m,6H),7.66(t,J=7.7Hz, 1H),7.49-7.54(m,6H),7.40-7.46(m,2H),2.43-2.47(m,2H),2.02-2.05(m,2H),1.93-1 .96(m,3H),1.79-1.87(m,5H),1.71-1.74(m,3H),1.64-1.65(m,2H),1.48-1.53(m,2H).

[0212] (Synthesis Example-22)

[0213] [ka] Under an argon atmosphere, 2-([1,1'-biphenyl]-4-yl)-4-phenyl-6-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine (1.58 g, 3.82 mmol), 4-(1-diamantyl)phenyl triflumethanesulfonate (1.66 g, 3.18 mmol), and tetrakis(triphenylphosphine)palladium (368 mg, 0.38 mol) were suspended in tetrahydrofuran (38 mL). To this suspension was added 2 M aqueous potassium phosphate solution (4.8 mL, 9.54 mmol), and the mixture was stirred at 80 °C for 15 hours. After cooling to room temperature, water and methanol were added, and the precipitated solid was collected by filtration. The collected material was dissolved in hot toluene, activated carbon was added, and the mixture was stirred, followed by filtration through Celite. The filtrate was concentrated and purified by recrystallization from toluene to give (1-135) as a white solid (yield: 1.43 g, 58%). The glass transition temperature was 133°C. 1 H-NMR(CDCl3)δ(ppm):9.05(t,J=1.6Hz,1H),8.88(d,J=8.6Hz,2H),8.81-8.84(m,2H),8. 75-8.78(m,1H),7.86-7.88(m,1H),7.83(d,J=8.6Hz,2H),7.72-7.75(m,4H),7.59-7.67( m,4H),7.50-7.54(m,4H),7.40-7.45(m,1H),2.43-2.46(m,2H),2.02-2.05(m,1H),1.93- 1.96(m,3H),1.79-1.88(m,5H),1.71-1.74(m,3H),1.65-1.66(m,2H),1.48-1.53(m,2H).

[0214] (Comparative Synthesis Example 1) Furthermore, a compound represented by the following structural formula described in Patent Document 1 (also referred to as ETL-1 in this specification) was synthesized according to the method described in Patent Document 1.

[0215] [ka]

[0216] <Fabrication of organic electric field element> Next, the obtained diamantane compound, ETL-1, was used to carry out device evaluation.

[0217] <<Element Example 1 (See Figure 2)>> (Preparation of substrate 101 and anode 102) A glass substrate with an indium-tin oxide (ITO) transparent electrode, patterned with a 2 mm wide stripe of ITO (110 nm thick), was prepared as a substrate with an anode on its surface. The substrate was then cleaned with isopropyl alcohol and then subjected to surface treatment using ozone and ultraviolet light.

[0218] (Preparation for vacuum deposition) After cleaning, each layer was deposited on the surface-treated substrate by vacuum deposition using a vacuum deposition method, and each layer was laminated. First, the glass substrate was placed in a vacuum deposition chamber. -4 The pressure was reduced to Pa. Then, each layer was formed in the following order according to the film formation conditions.

[0219] (Fabrication of Hole Injection Layer 103) Sublimation-purified N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine and 1,2,3-tris[(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane were deposited at a rate of 0.15 nm / s to form a 10 nm thick hole injection layer.

[0220] (Preparation of First Hole Transport Layer 1051) N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine was deposited at a rate of 0.15 nm / sec to a thickness of 85 nm to form a first hole transport layer.

[0221] (Fabrication of second hole transport layer 1052) A film of N-phenyl-N-(9,9-diphenylfluoren-2-yl)-N-(1,1'-biphenyl-4-yl)amine was formed to a thickness of 5 nm at a rate of 0.15 nm / second to form a second hole transport layer.

[0222] (Fabrication of the light-emitting layer 106) The light-emitting layer was formed by depositing a 20 nm thick film of 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tertbutylphenyl)]amino-bisbenzofuranyl-9,9'-spirofluorene in a mass ratio of 95:5 at a deposition rate of 0.18 nm / s.

[0223] (Fabrication of First Electron Transport Layer 1071) Sublimation-purified 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)[1,1'-biphenyl]-3-yl]-4,6-diphenyl-1,3,5-triazine (also referred to herein as ETL-2) was deposited to a thickness of 6 nm at a rate of 0.15 nm / s to form a first electron transport layer.

[0224] (Preparation of second electron transport layer 1072) The compound (1-6) synthesized in Synthesis Example 1 and 8-hydroxyquinolinolatolithium (hereinafter, Liq) were mixed in a mass ratio of 50:50 to form a 25 nm film, which formed the second electron transport layer. The film formation rate was 0.15 nm / sec.

[0225] (Fabrication of the cathode 108) Finally, a metal mask was placed perpendicular to the ITO stripes on the substrate, and the cathode 108 was formed. The cathode had a three-layer structure, with ytterbium, silver / magnesium (mass ratio 9 / 1), and silver deposited in that order to thicknesses of 2 nm, 12 nm, and 90 nm, respectively. The deposition rates for ytterbium, silver / magnesium, and silver were 0.02 nm / sec, 0.5 nm / sec, and 0.2 nm / sec, respectively.

[0226] As a result, the light-emitting area of ​​4mm as shown in Figure 2 2An organic electroluminescent device 100 was produced. The thickness of each film was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0227] The device was then sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less by sealing the glass sealing cap and the film-formed substrate (device) with bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

[0228] A direct current was applied to the organic electroluminescent device fabricated according to the above procedure, and the light-emitting characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse Co., Ltd.). 2 The current efficiency (cd / A) was measured when the current was passed through the electrode.

[0229] The voltage and current efficiencies are relative values, with the result of Comparative Example Element-1 set as the reference value (100). Table 1 shows the measurement results.

[0230] <<Element Example 2>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-27) synthesized in Synthesis Example 2 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0231] <<Element Example 3>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-87) synthesized in Synthesis Example 3 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0232] <<Element Example 4>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-19) synthesized in Synthesis Example 4 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0233] <<Element Example 6>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-8) synthesized in Synthesis Example 6 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0234] <<Element Example 7>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-9) synthesized in Synthesis Example 7 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0235] <<Element Example 8>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-103) synthesized in Synthesis Example 8 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0236] <<Element Example 9>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-104) synthesized in Synthesis Example 9 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0237] <<Element Example 15>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-100) synthesized in Synthesis Example 15 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0238] <<Element Example 18>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-128) synthesized in Synthesis Example 18 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0239] <<Element Example 19>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-28) synthesized in Synthesis Example 19 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0240] <<Element Example-20>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-130) synthesized in Synthesis Example 20 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0241] <<Element Example-21>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-134) synthesized in Synthesis Example 21 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0242] <<Element Example-22>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 1, except that compound (1-135) synthesized in Synthesis Example 22 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0243] <<Comparative element example 1>> An organic electroluminescent device was produced and evaluated in the same manner as in Element Example 1, except that ETL-1 was used instead of compound (1-6) in Element Example 1. The measurement results obtained are shown in Table 1.

[0244] [Table 1]

[0245] <<Element Example 5 (see Figure 2)>> (Preparation of substrate 101 and anode 102) A glass substrate with an indium-tin oxide (ITO) transparent electrode, patterned with a 2 mm wide stripe of ITO (110 nm thick), was prepared as a substrate with an anode on its surface. The substrate was then cleaned with isopropyl alcohol and then subjected to surface treatment using ozone and ultraviolet light.

[0246] (Preparation for vacuum deposition) After cleaning, each layer was deposited on the surface-treated substrate by vacuum deposition using a vacuum deposition method, and each layer was laminated. First, the glass substrate was placed in a vacuum deposition chamber. -4 The pressure was reduced to Pa. Then, each layer was formed in the following order according to the film formation conditions.

[0247] (Fabrication of Hole Injection Layer 103) Sublimation-purified N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine and 1,2,3-tris[(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane were deposited at a rate of 0.15 nm / s to form a 10 nm thick hole injection layer.

[0248] (Preparation of First Hole Transport Layer 1051) N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine was deposited at a rate of 0.15 nm / sec to a thickness of 85 nm to form a first hole transport layer.

[0249] (Fabrication of second hole transport layer 1052) A film of N-phenyl-N-(9,9-diphenylfluoren-2-yl)-N-(1,1'-biphenyl-4-yl)amine was formed to a thickness of 5 nm at a rate of 0.15 nm / second to form a second hole transport layer.

[0250] (Fabrication of the light-emitting layer 106) The light-emitting layer was formed by depositing a 20 nm thick film of 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tertbutylphenyl)]amino-bisbenzofuranyl-9,9'-spirofluorene in a mass ratio of 95:5 at a deposition rate of 0.18 nm / s.

[0251] (Fabrication of First Electron Transport Layer 1071) The compound 1-54 synthesized in Synthesis Example 5 was deposited at a rate of 0.15 nm / second to a thickness of 6 nm to form a first electron transport layer.

[0252] (Preparation of second electron transport layer 1072) A 25 nm thick film was formed by mixing sublimation-purified 4,6-diphenyl-2-(4-{4-[4'-cyano-(1,1'-biphenyl)-4-yl]naphthalen-1-yl}phenyl)-1,3,5-triazine and 8-hydroxyquinolinolatolithium (hereinafter referred to as Liq) in a 50:50 (mass ratio) mixture to form a second electron transport layer. The film formation rate was 0.15 nm / sec.

[0253] (Fabrication of the cathode 108) Finally, a metal mask was placed perpendicular to the ITO stripes on the substrate, and the cathode 108 was formed. The cathode had a three-layer structure, with ytterbium, silver / magnesium (mass ratio 9 / 1), and silver deposited in that order to thicknesses of 2 nm, 12 nm, and 90 nm, respectively. The deposition rates for ytterbium, silver / magnesium, and silver were 0.02 nm / sec, 0.5 nm / sec, and 0.2 nm / sec, respectively.

[0254] As a result, the light-emitting area of ​​4mm as shown in Figure 2 2 An organic electroluminescent device 100 was produced. The thickness of each film was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0255] The device was then sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less by sealing the glass sealing cap and the film-formed substrate (device) with bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

[0256] A direct current was applied to the organic electroluminescent device fabricated according to the above procedure, and the light-emitting characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse Co., Ltd.). 2 The current efficiency (cd / A) was measured when the current was passed through the electrode.

[0257] The voltage and current efficiencies are relative values, with the result of Comparative Example Element 2 set as the reference value (100). Table 2 shows the measurement results.

[0258] <<Comparative element example 2>> An organic electroluminescent device was produced and evaluated in the same manner as in Element Example 5, except that compound (ETL-2) described in Synthesis Example 11 of Patent Document 2 was used instead of compound (1-54). The measurement results obtained are shown in Table 2.

[0259] [Table 2]

[0260] <<Element Example 10 (see Figure 2)>> (Preparation of substrate 101 and anode 102) A glass substrate with an indium-tin oxide (ITO) transparent electrode, patterned with a 2 mm wide stripe of ITO (110 nm thick), was prepared as a substrate with an anode on its surface. The substrate was then cleaned with isopropyl alcohol and then subjected to surface treatment using ozone and ultraviolet light.

[0261] (Preparation for vacuum deposition) After cleaning, each layer was deposited on the surface-treated substrate by vacuum deposition using a vacuum deposition method, and each layer was laminated. First, the glass substrate was placed in a vacuum deposition chamber. -4 The pressure was reduced to Pa. Then, each layer was formed in the following order according to the film formation conditions.

[0262] (Fabrication of Hole Injection Layer 103) Sublimation-purified N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine and 1,2,3-tris[(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane were deposited at a rate of 0.15 nm / s to form a 10 nm thick hole injection layer.

[0263] (Preparation of First Hole Transport Layer 1051) The compound (1-106) synthesized in Synthesis Example 10 was deposited at a rate of 0.15 nm / sec to a thickness of 85 nm to form a first hole transport layer.

[0264] (Fabrication of second hole transport layer 1052) A film of N-phenyl-N-(9,9-diphenylfluoren-2-yl)-N-(1,1'-biphenyl-4-yl)amine was formed to a thickness of 5 nm at a rate of 0.15 nm / second to form a second hole transport layer.

[0265] (Fabrication of the light-emitting layer 106) The light-emitting layer was formed by depositing a 20 nm thick film of 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tertbutylphenyl)]amino-bisbenzofurano-9,9'-spirofluorene in a mass ratio of 95:5 at a deposition rate of 0.18 nm / s.

[0266] (Fabrication of First Electron Transport Layer 1071) Sublimation-purified 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)[1,1'-biphenyl]-3-yl]-4,6-diphenyl-1,3,5-triazine was deposited at a rate of 0.15 nm / sec to form a 6 nm film to form a first electron transport layer.

[0267] (Preparation of second electron transport layer 1072) A 25 nm thick film was formed by mixing sublimation-purified 4,6-diphenyl-2-(4-{4-[4'-cyano-(1,1'-biphenyl)-4-yl]naphthalen-1-yl}phenyl)-1,3,5-triazine and 8-hydroxyquinolinolatolithium (hereinafter referred to as Liq) in a 50:50 (mass ratio) mixture to form a second electron transport layer. The film formation rate was 0.15 nm / sec.

[0268] (Fabrication of the cathode 108) Finally, a metal mask was placed perpendicular to the ITO stripes on the substrate, and the cathode 108 was formed. The cathode had a three-layer structure, with ytterbium, silver / magnesium (mass ratio 9 / 1), and silver deposited in that order to thicknesses of 2 nm, 12 nm, and 90 nm, respectively. The deposition rates for ytterbium, silver / magnesium, and silver were 0.02 nm / sec, 0.5 nm / sec, and 0.2 nm / sec, respectively.

[0269] As a result, the light-emitting area of ​​4mm as shown in Figure 2 2 An organic electroluminescent device 100 was produced. The thickness of each film was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0270] The device was then sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less by sealing the glass sealing cap and the film-formed substrate (device) with bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

[0271] A direct current was applied to the organic electroluminescent device fabricated according to the above procedure, and the light-emitting characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse Co., Ltd.). 2 The current efficiency (cd / A) was measured when the current was passed through the electrode.

[0272] The current efficiency is a relative value with the result of Comparative Example Element 3 set as the reference value (100). Table 3 shows the measurement results.

[0273] <<Element Example 11>> An organic electroluminescent device was produced and evaluated in the same manner as in Element Example 10, except that compound (1-113) synthesized in Synthesis Example 11 was used instead of compound (1-106) in Element Example 10. The measurement results obtained are shown in Table 3.

[0274] <<Element Example 12>> An organic electroluminescent device was produced and evaluated in the same manner as in Element Example 10, except that compound (1-108) synthesized in Synthesis Example 12 was used instead of compound (1-106) in Element Example 10. The measurement results obtained are shown in Table 3.

[0275] <<Element Example 13>> An organic electroluminescent device was produced and evaluated in the same manner as in Element Example 10, except that compound (1-117) synthesized in Synthesis Example 13 was used instead of compound (1-106) in Element Example 10. The measurement results obtained are shown in Table 3.

[0276] <<Element Example 14>> An organic electroluminescent device was produced and evaluated in the same manner as in Element Example 10, except that compound (1-118) synthesized in Synthesis Example 14 was used instead of compound (1-106) in Element Example 10. The measurement results obtained are shown in Table 3.

[0277] <<Comparative element example 3>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Device Example 10, except that N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine (HTL-1) was used instead of compound (1-106) in Device Example 10. The measurement results obtained are shown in Table 3.

[0278] [Table 3]

[0279] <<Element Example 16 (see Figure 2)>> (Preparation of substrate 101 and anode 102) A glass substrate with an indium-tin oxide (ITO) transparent electrode, patterned with a 2 mm wide stripe of ITO (110 nm thick), was prepared as a substrate with an anode on its surface. The substrate was then cleaned with isopropyl alcohol and then subjected to surface treatment using ozone and ultraviolet light.

[0280] (Preparation for vacuum deposition) After cleaning, each layer was deposited on the surface-treated substrate by vacuum deposition using a vacuum deposition method, and each layer was laminated. First, the glass substrate was placed in a vacuum deposition chamber. -4 The pressure was reduced to Pa. Then, each layer was formed in the following order according to the film formation conditions.

[0281] (Fabrication of Hole Injection Layer 103) Sublimation-purified N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine and 1,2,3-tris[(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane were deposited at a rate of 0.15 nm / s to form a 10 nm thick hole injection layer.

[0282] (Preparation of First Hole Transport Layer 1051) The compound (1-106) synthesized in Synthesis Example 10 was deposited at a rate of 0.15 nm / sec to a thickness of 85 nm to form a first hole transport layer.

[0283] (Fabrication of second hole transport layer 1052) A film of N-phenyl-N-(9,9-diphenylfluoren-2-yl)-N-(1,1'-biphenyl-4-yl)amine was formed to a thickness of 5 nm at a rate of 0.15 nm / second to form a second hole transport layer.

[0284] (Fabrication of the light-emitting layer 106) The compound (1-122) synthesized in Synthesis Example 16 and 2,7-bis[N,N-di-(4-tertbutylphenyl)]amino-bisbenzofurano-9,9'-spirofluorene were mixed in a mass ratio of 95:5 to form a 20 nm film, which was used to form an emitting layer. The film formation rate was 0.18 nm / sec.

[0285] (Fabrication of First Electron Transport Layer 1071) Sublimation-purified 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)[1,1'-biphenyl]-3-yl]-4,6-diphenyl-1,3,5-triazine was deposited at a rate of 0.15 nm / sec to form a 6 nm film to form a first electron transport layer.

[0286] (Preparation of second electron transport layer 1072) A 25 nm thick film was formed by mixing sublimation-purified 4,6-diphenyl-2-(4-{4-[4'-cyano-(1,1'-biphenyl)-4-yl]naphthalen-1-yl}phenyl)-1,3,5-triazine and 8-hydroxyquinolinolatolithium (hereinafter referred to as Liq) in a 50:50 (mass ratio) mixture to form a second electron transport layer. The film formation rate was 0.15 nm / sec.

[0287] (Fabrication of the cathode 108) Finally, a metal mask was placed perpendicular to the ITO stripes on the substrate, and the cathode 108 was formed. The cathode had a three-layer structure, with ytterbium, silver / magnesium (mass ratio 9 / 1), and silver deposited in that order to thicknesses of 2 nm, 12 nm, and 90 nm, respectively. The deposition rates for ytterbium, silver / magnesium, and silver were 0.02 nm / sec, 0.5 nm / sec, and 0.2 nm / sec, respectively.

[0288] As a result, the light-emitting area of ​​4mm as shown in Figure 2 2 An organic electroluminescent device 100 was produced. The thickness of each film was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0289] The device was then sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less by sealing the glass sealing cap and the film-formed substrate (device) with bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

[0290] A direct current was applied to the organic electroluminescent device fabricated according to the above procedure, and the light-emitting characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse Co., Ltd.). 2 The current efficiency (cd / A) was measured when the current was passed through the electrode.

[0291] The current efficiency is a relative value with the result of Comparative Example Element 4 set as the reference value (100). Table 4 shows the measurement results.

[0292] <<Element Example 17>> An organic electroluminescent device was produced and evaluated in the same manner as in Element Example 16, except that compound (1-125) synthesized in Synthesis Example 17 was used instead of compound (1-122) in Element Example 16. The measurement results obtained are shown in Table 4.

[0293] <<Comparative element example-4>> An organic electroluminescent device was fabricated and evaluated in the same manner as in Element Example 16, except that 3-(10-phenyl-9-anthryl)-dibenzofuran (EML-1) was used instead of compound (1-122). The measurement results are shown in Table 4.

[0294] [Table 4]

[0295] The diamantane compound according to one embodiment of the present invention can provide an organic electroluminescent device that is excellent in luminous efficiency, more preferably excellent in driving voltage and luminous efficiency.

[0296] Furthermore, the diamantane compound according to one embodiment of the present invention can be used as a material for organic electroluminescent elements (specifically, an electron transport material for organic electroluminescent elements, a hole transport material for organic electroluminescent elements, etc.) that contributes to the production of organic electroluminescent elements that are excellent in luminous efficiency, more preferably, have a low driving voltage and are excellent in luminous efficiency. Furthermore, the diamantane compound according to one embodiment of the present invention can provide an organic electroluminescent element with high luminous efficiency, more preferably, an organic electroluminescent element with low power consumption and high luminous efficiency. [Explanation of symbols]

[0297] 100. Organic electroluminescent devices 1. Substrate 2. Anode 3. Hole injection layer 4. Hole transport layer 5. Emitting layer 6. Electron transport layer 7. Electron injection layer 8. Cathode 101. Circuit Board 102. Anode 103. Hole injection layer 105. Hole transport layer 1051. First hole transport layer 1052. Second hole transport layer 106. Emitting layer 107. Electron transport layer 1071. First electron transport layer 1072. Second electron transport layer 108. Cathode

Claims

1. A material for organic electroluminescent devices containing a diamantane compound, The diamantane compound is a material for an organic electroluminescent device, which is a diamantane compound having a group represented by the following formula (1) and a group represented by the following formula (2): 【Chemical 1】 (In formula (1), a carbon atom in the diamantane ring may be substituted with an aryl group having 6 to 12 carbon atoms. In formula (1), * represents a bond, and a represents an integer of 1 to 6.) 【Chemistry 2】 (Ar in formula (2) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. However, the total number of carbon atoms constituting Ar is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group having 6 to 60 carbon atoms as defined in (i) above, the total number of carbon atoms constituting Ar is 13 or more. In formula (2), * represents a bond, and b represents an integer of 1 to 6.

2. A diamantane compound having a group represented by the following formula (1) and a group represented by the following formula (2), the diamantane compound not including a dipolar compound: 【Chemistry 3】 (In formula (1), a carbon atom in the diamantane ring may be substituted with an aryl group having 6 to 12 carbon atoms. In formula (1), * represents a bond, and a represents an integer of 1 to 6.) 【Chemistry 4】 (Ar in formula (2) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. However, the total number of carbon atoms constituting Ar is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group having 6 to 60 carbon atoms as defined in (i) above, the total number of carbon atoms constituting Ar is 13 or more. In formula (2), * represents a bond. b represents an integer of 1 to 6. The substituent in the (i) optionally substituted aromatic hydrocarbon group or the (ii) optionally substituted heteroaromatic group is selected from the group consisting of a fluorine atom, a cyano group, a nitro group, and an alkyl group having 1 carbon atom.

3. The diamantane compound according to claim 2, which is represented by the following formula (3) or (4): 【Chemistry 5】 In the diamantane ring in formula (3), a carbon atom other than the carbon atom bonded to the —Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. In formula (3), each Ar is independently (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. However, each Ar in formula (3) independently has a total number of carbon atoms constituting Ar of 8 or more, and when Ar is composed only of the aromatic hydrocarbon group having 6 to 60 carbon atoms as defined in (i) above, the total number of carbon atoms constituting Ar is 13 or more. In formula (3), m represents an integer of 1, 2, or 3. The substituent in the (i) optionally substituted aromatic hydrocarbon group or the (ii) optionally substituted heteroaromatic group is selected from the group consisting of a fluorine atom, a cyano group, a nitro group, and an alkyl group having 1 carbon atom. 【Chemistry 6】 In the diamantane ring in formula (4), each carbon atom other than the carbon atom bonded to the —Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (4) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. However, in the formula (4), the total number of carbon atoms constituting Ar is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group having 6 to 60 carbon atoms as defined in (i) above, the total number of carbon atoms constituting Ar is 13 or more. In formula (4), n represents an integer of 2 or 3. The substituent in the (i) optionally substituted aromatic hydrocarbon group or the (ii) optionally substituted heteroaromatic group is selected from the group consisting of a fluorine atom, a cyano group, a nitro group, and an alkyl group having 1 carbon atom.

4. The diamantane compound according to claim 3, wherein the diamantane compound is represented by any one of the following formulas (3-1) to (3-3): 【Chemistry 7】 【Chemistry 8】 【Chemistry 9】 In the diamantane rings of formulas (3-1) to (3-3), carbon atoms other than the carbon atom bonded to the —Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (3-1) to formula (3-3) is each independently (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. However, each Ar in formulas (3-1) to (3-3) independently has a total of 8 or more carbon atoms constituting Ar, and when Ar is composed only of the aromatic hydrocarbon group (i) having 6 to 60 carbon atoms, the total number of carbon atoms constituting Ar is 13 or more. The substituent in the (i) optionally substituted aromatic hydrocarbon group or the (ii) optionally substituted heteroaromatic group is selected from the group consisting of a fluorine atom, a cyano group, a nitro group, and an alkyl group having 1 carbon atom.

5. The diamantane compound according to claim 3, wherein the diamantane compound is represented by any one of the following formulas (4-1) to (4-2): 【Chemistry 10】 【Chemistry 11】 In the diamantane rings of formulas (4-1) and (4-2), each carbon atom other than the carbon atom bonded to the -Ar group may be substituted with an aryl group having 6 to 12 carbon atoms. Ar in formula (4-1) to formula (4-2) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. However, in the formulas (4-1) and (4-2), the total number of carbon atoms constituting Ar is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group having 6 to 60 carbon atoms of (i) above, the total number of carbon atoms constituting Ar is 13 or more. The substituent in the (i) optionally substituted aromatic hydrocarbon group or the (ii) optionally substituted heteroaromatic group is selected from the group consisting of a fluorine atom, a cyano group, a nitro group, and an alkyl group having 1 carbon atom.

6. 3. The diamantane compound according to claim 2, wherein the heteroaromatic group is a single ring or fused ring containing any one of a nitrogen atom, an oxygen atom, and a sulfur atom, or a linked ring to which any ring selected from these rings is linked.

7. the aromatic hydrocarbon group contains an arylamino group, 3. The diamantane compound of claim 2, wherein the heteroaromatic group comprises a heterocyclic amino group.

8. 7. The diamantane compound according to claim 6, wherein the diamantane compound has the (ii) optionally substituted heteroaromatic group having 3 to 60 carbon atoms and containing any one of a nitrogen atom, an oxygen atom, and a sulfur atom.

9. 9. The diamantane compound according to claim 8, wherein the diamantane compound has the optionally substituted heteroaromatic group (ii) having 3 to 60 carbon atoms and containing a nitrogen atom.

10. The diamantane compound according to claim 2 , which has a fused-ring aromatic hydrocarbon group having 14 or more carbon atoms.

11. 3. The diamantane compound according to claim 2, wherein the diamantane ring has no aryl group substituted on any carbon atom other than the carbon atom bonded to the -Ar group.

12. An organic electroluminescent material comprising the diamantane compound according to claim 2.

13. The material for organic electroluminescent devices according to claim 1 , wherein the material for organic electroluminescent devices is an electron transport material for organic electroluminescent devices or a hole transport material for organic electroluminescent devices.

14. An organic electroluminescent device containing a diamantane compound, The diamantane compound is a diamantane compound having a group represented by the following formula (1) and a group represented by the following formula (2): 【Chemistry 12】 (In formula (1), a carbon atom in the diamantane ring may be substituted with an aryl group having 6 to 12 carbon atoms. In formula (1), * represents a bond, and a represents an integer of 1 to 6.) 【Chemistry 13】 (Ar in formula (2) is (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. However, the total number of carbon atoms constituting Ar is 8 or more, and when Ar is composed only of the aromatic hydrocarbon group having 6 to 60 carbon atoms as defined in (i) above, the total number of carbon atoms constituting Ar is 13 or more. In formula (2), * represents a bond, and b represents an integer of 1 to 6.

15. A diamantane compound represented by the following formula (5) or (6): 【Chemistry 14】 (In the diamantane ring in formula (5), -L １ -X １ Carbon atoms other than the carbon atom bonded to the group may be substituted with an aryl group having 6 to 12 carbon atoms. L in formula (5) １ are each independently (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. L １ The total number of carbon atoms constituting the group is 8 or more. X in formula (5) １ represents a halogen atom or a trifluoromethanesulfonyloxy group. In formula (5), p and q each represent an integer of 1. 【Chemistry 15】 (In the diamantane ring in formula (6), -L ２ -B(OR １ ) ２ Carbon atoms other than the carbon atom bonded to the group may be substituted with an aryl group having 6 to 12 carbon atoms. L in formula (6) ２ are each independently a single bond, or (i) an optionally substituted aromatic hydrocarbon group having 6 to 60 carbon atoms; (ii) an optionally substituted heteroaromatic group having 3 to 60 carbon atoms, or (iii) represents a group in which the groups (i) and (ii) are combined. R in formula (6) １ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. B(OR １ ) ２ The two R's １ may be the same or different. １ may be joined together to form a ring containing the oxygen atom and the boron atom. In formula (6), p and q each represent an integer of 1.

16. In the diamantane ring in the formula (5), carbon atoms other than the carbon atom bonded to the -L 1 -X 1 group have no substituents, 16. The diamantane compound according to claim 15, wherein in the diamantane ring in said formula (6), carbon atoms other than the carbon atom bonded to the -L 2 -B(OR 1 ) 2 group have no substituent.

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