JP5672667B2 - Benzo [a] carbazole compound, light-emitting material containing the compound, and organic electroluminescent device using the same - Google Patents

Description

The present invention relates to a benzo [a] carbazole compound, a light-emitting material containing the compound, an organic electroluminescence device using the light-emitting material (hereinafter sometimes abbreviated as an organic EL device), and the like.

The organic EL element is a self-luminous light emitting element and is expected as a light emitting element for display or illumination. 2. Description of the Related Art Conventionally, various display devices using light emitting elements that emit electroluminescence have been studied because they can be reduced in power and thinned. Furthermore, organic EL elements made of organic materials can be easily reduced in weight and size. It has been actively studied.

The organic EL element has a structure composed of a pair of electrodes composed of an anode and a cathode, and a single layer or a plurality of layers disposed between the pair of electrodes and containing an organic compound. The layer containing an organic compound includes a light-emitting layer and a charge transport / injection layer that transports or injects charges such as holes and electrons. Various organic materials have been developed as the organic compound. In particular, research and development of organic materials for the light emitting layer are actively conducted.

The light emitting material of the organic EL element is classified into a fluorescent material using singlet excitons and a phosphorescent material using triplet states depending on the light emission mechanism. It is known that the theoretical luminous efficiency is improved about 4 times by using a phosphorescent material as the light emitting material of the organic EL element (see Non-Patent Document 1).

In a phosphorescent organic EL device, phosphorescence emission is extracted by doping a host material with a metal complex light emitting material containing a heavy metal such as platinum or iridium as a dopant that emits phosphorescence (hereinafter abbreviated as phosphorescent dopant) (non-patent document). Reference 1). The light emission efficiency and light emission lifetime of the phosphorescent dopant depend on the host material. The basic performance required for the host material of the phosphorescent organic EL device is that it has a hole transporting property and an electron transporting property, and the triplet state energy level (T1) of the host material is the triplet state energy level of the phosphorescent dopant. It is higher than (T1). In order to put phosphorescent organic EL elements into practical use, green phosphorescent host materials have been actively developed so far (see, for example, Patent Document 1, Patent Document 2, and Non-Patent Document 2). Many of these green phosphorescent host materials are characterized by using a material containing a carbazolyl group. For example, it is well known to use 4,4-N, N′-dicarbazole-biphenyl (hereinafter abbreviated as CBP) (see, for example, Patent Document 3 and Non-Patent Document 1). However, since CBP has a symmetric molecular structure and has a property of being easily crystallized, there is a concern that the stability of the light emitting layer containing the compound is poor. For these reasons, the phosphorescent organic EL element has a serious problem in driving stability of the element for practical use.

JP 2005-174917 A JP 2008-311528 A JP 2001-313178 A

Apllied Physics Letters, 75, 4 (1999) Thin Solid Films, 436, 264 (2003)

From the actual situation as described above, an organic EL element having sufficient performance with respect to heat resistance, driving voltage, light emission efficiency, current efficiency, element lifetime, external quantum efficiency, and the like has not been obtained yet. Under such circumstances, it is desired to develop an organic EL element, in particular, a phosphorescent organic EL element, having better performance in heat resistance, driving voltage, light emission efficiency, current efficiency, element lifetime, external quantum efficiency, and the like. That is, there is a demand for the development of a compound capable of obtaining the device, in particular, a green phosphorescent host material that can form a stable light-emitting layer that is difficult to crystallize and realizes high efficiency and high driving stability. There is nothing else.

Also, in order to cope with the mass production of full-color flat panel displays, it is necessary to develop a host material that has high performance and can be used simultaneously with fluorescence and phosphorescence.

As a result of intensive studies to solve the above problems, the present inventors have succeeded in producing a benzo [a] carbazole compound represented by the following formula (1). In addition, an organic electroluminescent device is configured by arranging this benzo [a] carbazole compound-containing layer between a pair of electrodes, thereby improving driving voltage, luminous efficiency, current efficiency, device lifetime, external quantum efficiency, and the like. As a result, it was found that a phosphorescent organic EL device excellent in green light emission characteristics was obtained, and the present invention was completed.

The terms used in the present invention are defined as follows. Alkyl may be a linear group or a branched group. The term “arbitrary” used in the present invention indicates that the position and the number are arbitrary, and means “at least one selected without distinction”. When a plurality of atoms (hydrogen) are replaced with groups, each may be replaced with a different group. Further, in the present specification, the “compound represented by the formula (1-1)” may be expressed as “compound (1-1)”.

式（１）中、Ａｒは置換されていてもよいアリールまたは置換されていてもよいヘテロアリールであり、Ｒ^１〜Ｒ^１６はそれぞれ独立して、水素、置換されていてもよいアルキル、置換されていてもよいシクロアルキル、置換されていてもよいアリール、または置換されていてもよいヘテロアリールである。 Said subject is solved by each item shown below.
[1] A compound represented by the following formula (1).

In the formula (1), Ar is an optionally substituted aryl or an optionally substituted heteroaryl, and R ^{1 to} R ¹⁶ are each independently hydrogen, an optionally substituted alkyl, a substituted Optionally substituted cycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl.

[2] Ar is optionally substituted aryl having 6 to 30 carbon atoms, optionally substituted heteroaryl having 2 to 30 carbon atoms, and R ^{1 to} R ¹⁶ are each independently hydrogen, substituted An optionally substituted alkyl having 1 to 24 carbon atoms, an optionally substituted cycloalkyl having 3 to 12 carbon atoms, an optionally substituted aryl having 6 to 30 carbon atoms, or an optionally substituted carbon The compound according to item [1], which is heteroaryl having 2 to 30.

[3] Ar is an optionally substituted aryl having 6 to 20 carbon atoms, an optionally substituted heteroaryl having 2 to 20 carbon atoms, and R ^{1 to} R ¹⁶ are all hydrogen. ] The compound according to item.

[4] The compound according to item [1], represented by the following formula (1-1).

[5] A luminescent material containing the compound according to any one of [1] to [4].

[6] In an organic electroluminescent device having at least one organic compound layer sandwiched between a pair of electrodes consisting of an anode and a cathode, the compound according to any one of [1] to [4] is added to the organic electroluminescent device. An organic electroluminescent element contained in the compound layer.

[7] The organic electroluminescent element according to the above [6], wherein the light-emitting layer contains the compound according to any one of the above [1] to [4].

[8] The organic electroluminescent element according to the above [7], further comprising an iridium complex, a platinum complex or a rhenium complex in the light emitting layer.

[9] Further, it has an electron transport layer and / or an electron injection layer disposed between the cathode and the light emitting layer, and at least one of the electron transport layer and the electron injection layer is a quinolinol-based metal complex or a pyridine derivative. And the organic electroluminescence device according to the item [7] or [8], which contains at least one selected from the group consisting of phenanthroline derivatives.

According to a preferred embodiment of the present invention, for example, a benzo [a] carbazole compound having excellent characteristics as a light emitting layer material can be provided. In addition, an organic EL element improved in heat resistance, drive voltage, light emission efficiency, current efficiency, element lifetime, external quantum efficiency, and the like can be provided. The benzo [a] carbazole compound according to a preferred embodiment of the present invention can be used as a host material for a phosphorescent device, particularly a green phosphorescent organic EL device, and a green phosphorescent organic EL device having high efficiency and high driving stability can be obtained. . Further, the benzo [a] carbazole compound according to a preferred embodiment of the present invention has an advantage that it can be applied not only to a phosphorescent device but also to a fluorescent device. For example, the benzo [a] carbazole compound according to a preferred embodiment of the present invention can be used not only as a green phosphorescent device but also as a host material for red phosphorescent devices, and further as a host material for fluorescent blue devices. As a result, a material suitable for mass production of a full color flat panel display can be provided. By using the organic EL element of the present invention, a high-performance display device such as full-color display can be created.

式（１）中、Ａｒは置換されていてもよいアリールまたは置換されていてもよいヘテロアリールであり、Ｒ^１〜Ｒ^１６はそれぞれ独立して、水素、置換されていてもよいアルキル、置換されていてもよいシクロアルキル、置換されていてもよいアリール、または置換されていてもよいヘテロアリールである。 Hereinafter, the present invention will be described in more detail.
1. Benzo [a] carbazole compound represented by formula (1) First, the benzo [a] carbazole compound represented by formula (1) will be described.

In the formula (1), Ar is an optionally substituted aryl or an optionally substituted heteroaryl, and R ^{1 to} R ¹⁶ are each independently hydrogen, an optionally substituted alkyl, a substituted Optionally substituted cycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl.

Examples of “aryl” of “optionally substituted aryl” in Ar and R ^{1 to} R ¹⁶ in formula (1) include “aryl having 6 to 30 carbon atoms”. The “aryl” for Ar is preferably “aryl having 6 to 20 carbon atoms”.

Examples of “C6-C30 aryl” are phenyl, 1-naphthyl, 2-naphthyl, acenaphthylene-1-yl, acenaphthylene-3-yl, acenaphthylene-4-yl, acenaphthylene-5-yl, fluorene-1 -Yl, fluoren-2-yl, fluoren-3-yl, fluoren-4-yl, fluoren-9-yl, phenalen-1-yl, phenalen-2-yl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl 4-phenanthryl, 9-phenanthryl, fluoranthen-1-yl, fluoranthen-2-yl, fluoranthen-3-yl, fluoranthen-7-yl, fluoranthen-8-yl, triphenylene-1-yl, triphenylene-2-yl 2-biphenylyl, 3-biphenylyl, 4-biphenylyl m-terphenyl-2′-yl, m-terphenyl-4′-yl, m-terphenyl-5′-yl, o-terphenyl-3′-yl, o-terphenyl-4′-yl, p-terphenyl-2′-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl -3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, p-terphenyl-4-yl, 5'-phenyl-m-terphenyl 2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, m-quaterphenyl-2-yl, m-quaterphenyl-3 -Yl, m-quaterphenyl-4-yl, o- Ater phenyl-2-yl, o- quaterphenyl-3-yl, and o- quaterphenyl-4-yl. Of these, phenyl, 2-biphenylyl, 3-biphenylyl, 4-biphenylyl, 1-naphthyl, 9-phenanthryl, triphenylene-1-yl, and triphenylene-2-yl are preferred.

Arbitrary hydrogen in "C6-C30 aryl" is C1-C24 alkyl, C3-C12 cycloalkyl, C6-C30 aryl, C2-C30 heteroaryl, or silyl May be replaced. The number of substituents is, for example, the maximum possible number of substitution, preferably 0-3, more preferably 0-2, and even more preferably 0 (unsubstituted).

Examples of “alkyl having 1 to 24 carbon atoms” are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, n -Hexyl, isohexyl, 1-methylpentyl, 2-methylpentyl, n-hexyl, isohexyl, 1-methylpentyl, 2-methylpentyl, and 5-methylhexyl.

Examples of “aryl having 6 to 30 carbon atoms” in which any hydrogen is replaced by alkyl having 1 to 24 carbon atoms include o-tolyl, m-tolyl, p-tolyl, 2,4-dimethylphenyl, 2,6 -Dimethylphenyl, 2,4,6-trimethylphenyl, 4-tert-butylphenyl, 2,4-ditert-butylphenyl, 2,4,6-tritert-butylphenyl, 4-methyl-1-naphthyl, 4-tert-butyl-1-naphthyl, 6-methyl-2-naphthyl, 6-tert-butyl-2-naphthyl, and 9,9-dimethyl-2-fluorenyl.

Examples of “C3-C12 cycloalkyl” are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclopentyl, cycloheptyl, methylcyclohexyl, cyclooctyl, and dimethylcyclohexyl.

Examples of “aryl having 6 to 30 carbon atoms” in which any hydrogen is replaced by cycloalkyl having 3 to 12 carbon atoms include 2-cyclohexylphenyl, 3-cyclohexylphenyl, 4-cyclohexylphenyl, and 2,4-dicyclohexylphenyl. 3,5-dicyclohexylphenyl 4-cyclohexyl-1-naphthyl, 6-cyclohexyl-2-naphthyl, and 9,9-dicyclohexyl-2-fluorenyl.

Examples of “aryl having 6 to 30 carbon atoms” in which any hydrogen is replaced by aryl having 6 to 30 carbon atoms include 2- (1-naphthyl) phenyl, 3- (1-naphthyl) phenyl, 4- (1 -Naphthyl) phenyl, 2- (2-naphthyl) phenyl, 3- (2-naphthyl) phenyl, 4- (2-naphthyl) phenyl, 4- (9-phenanthryl) phenyl, 2-phenyl-1-naphthyl, 4 -Phenyl-1-naphthyl, 5-phenyl-1-naphthyl, 1-phenyl-2-naphthyl, 3-phenyl-2-naphthyl, 6-phenyl-2-naphthyl, 7-phenyl-2-naphthyl, 4- ( 4-biphenylyl) -1-naphthyl, 6- (4-biphenylyl) -2-naphthyl, 6- (m-terphenyl-2′-yl) -2-naphthyl, 6- (m-terphenyl-5′- Il 2-naphthyl, 4- (m-terphenyl-2′-yl) -1-naphthyl, 4- (m-terphenyl-5′-yl) -1-naphthyl, 2- (1-naphthyl) -1 -Naphthyl, 4- (1-naphthyl) -1-naphthyl, 5- (1-naphthyl) -1-naphthyl, 2- (2-naphthyl) -1-naphthyl, 4- (2-naphthyl) -1-naphthyl 5- (2-naphthyl) -1-naphthyl, 1- (1-naphthyl) -2-naphthyl, 3- (1-naphthyl) -2-naphthyl, 6- (1-naphthyl) -2-naphthyl, 7 -(1-naphthyl) -2-naphthyl, 1- (2-naphthyl) -2-naphthyl, 3- (2-naphthyl) -2-naphthyl, 6- (2-naphthyl) -2-naphthyl, 7- ( 2-naphthyl) -2-naphthyl, 4- (9-phenanthryl) -1-naphthyl 6- (9-phenanthryl) -2-naphthyl, 9,9-diphenyl-2-fluorenyl, 3-phenyl-9-phenanthryl, 10-phenyl-9-phenanthryl, 3- (1-naphthyl) -9-phenanthryl, 10- (1-naphthyl) -9-phenanthryl, 3- (2-naphthyl) -9-phenanthryl, and 10- (2-naphthyl) -9-phenanthryl.

Examples of the “heteroaryl having 2 to 30 carbon atoms” include, for example, a heterocyclic group containing 1 to 5 heteroatoms selected from an oxygen atom, a sulfur atom and a nitrogen atom in addition to a carbon atom as a ring constituent atom. Examples thereof include aromatic heterocyclic groups.

Examples of "heterocyclic groups" are pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, 1H-indazolyl, benzoimidazolyl, Benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenazinyl, and indolizinyl.

Examples of “aromatic heterocyclic groups” are furyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, oxadiazolyl, furazanyl, thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, benzofuranyl , Isobenzofuranyl, benzo [b] thienyl, indolyl, isoindolyl, 1H-indazolyl, benzoimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, Purinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenazinyl, fur Nokisachiiniru, thianthrenyl, and indolizinyl.

Examples of “C6-C30 aryl” in which any hydrogen is replaced by C2-C30 heteroaryl are 2- (pyridin-2-yl) phenyl, 3- (pyridin-2-yl) phenyl 4- (pyridin-2-yl) phenyl, 2- (pyridin-3-yl) phenyl, 3- (pyridin-3-yl) phenyl, 4- (pyridin-3-yl) phenyl, 2- (pyridin- 4-yl) phenyl, 3- (pyridin-4-yl) phenyl, 4- (pyridin-4-yl) phenyl, 2- (carbazol-9-yl) phenyl, 3- (carbazol-9-yl) phenyl, 4- (carbazol-9-yl) phenyl, 2- (imidazol-1-yl) phenyl, 3- (imidazol-1-yl) phenyl, 4- (imidazol-1-yl) phenyl, 2- (benzo Zo [d] imidazol-1-yl) phenyl, 3- (benzo [d] imidazol-1-yl) phenyl, 4- (benzo [d] imidazol-1-yl) phenyl, 2- (1-phenylbenzo [ d] imidazol-2-yl) phenyl, 3- (1-phenylbenzo [d] imidazol-2-yl) phenyl, 4- (1-phenylbenzo [d] imidazol-2-yl) phenyl, 4- (pyridine) 2-yl) naphthalen-1-yl, 6- (pyridin-2-yl) naphthalen-2-yl, 7- (pyridin-2-yl) naphthalen-2-yl, 4- (pyridin-3-yl) Naphthalen-1-yl, 6- (pyridin-3-yl) naphthalen-2-yl, 7- (pyridin-3-yl) naphthalen-2-yl, 4- (pyridin-4-yl) naphthalene -Yl, 6- (pyridin-4-yl) naphthalen-2-yl, 7- (pyridin-4-yl) naphthalen-2-yl, 4- (carbazol-9-yl) naphthalen-1-yl, 6- (Carbazol-9-yl) naphthalen-2-yl, 7- (carbazol-9-yl) naphthalen-2-yl, 4- (imidazol-1-yl) naphthalen-1-yl, 6- (imidazole-1- Yl) naphthalen-2-yl, 7- (imidazol-1-yl) naphthalen-2-yl, 4- (benzo [d] imidazol-1-yl) naphthalen-1-yl, 6- (benzo [d] imidazole -1-yl) naphthalen-2-yl, 7- (benzo [d] imidazol-1-yl) naphthalen-2-yl, 4- (1-phenylbenzo [d] imidazol-2-yl) naphth Talen-1-yl, 6- (1-phenylbenzo [d] imidazol-2-yl) naphthalen-2-yl, and 7- (1-phenylbenzo [d] imidazol-2-yl) naphthalen-2-yl It is.

Examples of silyl are silyl substituted with hydrogen, alkyl having 1 to 24 carbons, cycloalkyl having 3 to 12 carbons or aryl having 6 to 30 carbons, such as trimethylsilyl, triethylsilyl, triisopropylsilyl, tert -Butyldimethylsilyl, tert-butyldiphenylsilyl, and triphenylsilyl.

Examples of “aryl” in which any hydrogen is replaced by silyl are 2-trimethylsilylphenyl, 3-trimethylsilylphenyl, 4-trimethylsilylphenyl, 2-triethylsilylphenyl, 3-triethylsilylphenyl, 4-triethylsilylphenyl, 2 -Triphenylsilylphenyl, 3-triphenylsilylphenyl, 4-triphenylsilylphenyl, 2,4-bis (trimethylsilyl) phenyl, 3,5-bis (trimethylsilyl) phenyl, 4-trimethylsilyl-1-naphthyl, 6- Trimethylsilyl-2-naphthyl 4-trimethylsilyl-1-anthryl, 10-trimethylsilyl-9-anthryl, and 9,9-bis (trimethylsilyl) -2-fluorenyl.

Examples of “heteroaryl” of “optionally substituted heteroaryl” in Ar and R ^{1 to} R ¹⁶ in the formula (1) include “heteroaryl having 2 to 30 carbon atoms”. The “heteroaryl” for Ar is preferably “heteroaryl having 2 to 20 carbon atoms”. Examples of the “heteroaryl having 2 to 30 carbon atoms” include the same groups as the “heteroaryl having 2 to 30 carbon atoms” listed as the substituent of the above “aryl”. Of these groups, pyridyl, indolyl and carbazolyl are preferred.

Any hydrogen in “heteroaryl” may be replaced with alkyl having 1 to 24 carbons, cycloalkyl having 3 to 12 carbons, aryl having 6 to 30 carbons, heteroaryl having 2 to 30 carbons, or silyl. Good. The number of substituents is, for example, the maximum possible number of substitution, preferably 0-3, more preferably 0-2, and even more preferably 0 (unsubstituted). Examples of alkyl having 1 to 24 carbon atoms, cycloalkyl having 3 to 12 carbon atoms, aryl having 6 to 30 carbon atoms, heteroaryl having 2 to 30 carbon atoms, or silyl are the groups described in the description of the above “aryl”. Are illustrated as well.

Examples of “heteroaryl having 2 to 30 carbon atoms” in which any hydrogen is replaced by alkyl having 1 to 24 carbon atoms include 5-methyl-2-thienyl, 5-methyl-3-thienyl, 2,5-dimethyl -3-thienyl, 3,4,5-trimethyl-2-thienyl, 3-methyl-2-benzothienyl, 2-methyl-3-benzothienyl, 6-methyl-2-pyridyl, 5-methyl-2-pyridyl 4-methyl-2-pyridyl, 3-methyl-2-pyridyl, 6-methyl-3-pyridyl, 5-methyl-3-pyridyl, 4-methyl-3-pyridyl, 2-methyl-3-pyridyl, 2 -Methyl-4-pyridyl, 3-methyl-4-pyridyl, 2-methyl-1-indolyl, 2-tert-butyl-1-indolyl, 3-methyl-9-carbazolyl, 3,6-dimethyl-9-carbazo Le, a 3,6-di tert- butyl-9-carbazolyl, and 9-methyl-3-carbazolyl.

Examples of “heteroaryl having 2 to 30 carbon atoms” in which any hydrogen is replaced by cycloalkyl having 3 to 12 carbon atoms include 5-cyclohexyl-2-thienyl, 5-cyclohexyl-3-thienyl, 2,5- Dicyclohexyl-3-thienyl, 3,4,5-tricyclohexyl-2-thienyl, 3-cyclohexyl-2-benzothienyl, 2-cyclohexyl-3-benzothienyl, 6-cyclohexyl-2-pyridyl, 5-cyclohexyl-2 -Pyridyl, 4-cyclohexyl-2-pyridyl, 3-cyclohexyl-2-pyridyl, 6-cyclohexyl-3-pyridyl, 5-cyclohexyl-3-pyridyl, 4-cyclohexyl-3-pyridyl, 2-cyclohexyl-3-pyridyl 2-cyclohexyl-4-pyridyl, 3-cyclohexyl-4-pi Jill, 2-cyclohexyl-1-indolyl, 3-cyclohexyl-9-carbazolyl, 3,6-dicyclohexyl-9-carbazolyl, and 9-cyclohexyl-3-carbazolyl.

Examples of “heteroaryl having 2 to 30 carbon atoms” in which any hydrogen is replaced by aryl having 6 to 30 carbon atoms include 5-phenyl-2-thienyl, 5- (1-naphthyl) -2-thienyl, 5 -(2-naphthyl) -2-thienyl, 5-phenyl-3-thienyl, 2,5-diphenyl-3-thienyl, 2-phenyl-5- (1-naphthyl) -3-thienyl, 2-phenyl-5 -(2-naphthyl) -3-thienyl, 3,4,5-triphenyl-2-thienyl, 3,4-diphenyl-5- (1-naphthyl) -2-thienyl, 3,4-diphenyl-5 (2-naphthyl) -2-thienyl, 3-phenyl-2-benzothienyl, 3- (1-naphthyl) -2-benzothienyl, 3- (2-naphthyl) -2-benzothienyl, 2-phenyl-3 -Benzothienyl, 6-ph Nyl-2-pyridyl, 5-phenyl-2-pyridyl, 4-phenyl-2-pyridyl, 3-phenyl-2-pyridyl, 6-phenyl-3-pyridyl, 5-phenyl-3-pyridyl, 4-phenyl- 3-pyridyl, 2-phenyl-3-pyridyl, 2-phenyl-4-pyridyl, 3-phenyl-4-pyridyl, 3-phenyl-9-carbazolyl, 3- (1-naphthyl) -9-carbazolyl, 3- (2-naphthyl) -9-carbazolyl, 3,6-diphenyl-9-carbazolyl, 3,6-di (1-naphthyl) -9-carbazolyl, 3,6-di (2-naphthyl) -9-carbazolyl, 3,6-di (4-ter
t-butylphenyl) -9-carbazolyl, 9-phenyl-3-carbazolyl, 9- (1-naphthyl) -3-carbazolyl, and 9- (2-naphthyl) -3-carbazolyl.

Examples of “C2-C30 heteroaryl” in which any hydrogen is replaced by C2-C30 heteroaryl are 2,2′-bipyridyl-6-yl, 2,3′-bipyridyl-6- Yl, 2,4′-bipyridyl-6-yl, 3,2′-bipyridyl-6-yl, 3,3′-bipyridyl-6-yl, 3,4′-bipyridyl-6-yl, 3- (indole) -1-yl) pyridin-2-yl, 4- (indol-1-yl) pyridin-2-yl, 5- (indol-1-yl) pyridin-2-yl, 6- (indol-1-yl) Pyridin-2-yl, 2- (indol-1-yl) pyridin-3-yl, 4- (indol-1-yl) pyridin-3-yl, 5- (indol-1-yl) pyridin-3-yl , 6- (Indol-1-yl) pyridine- -Yl, 2- (indol-1-yl) pyridin-4-yl, 3- (indol-1-yl) pyridin-4-yl, 3- (carbazol-9-yl) pyridin-2-yl, 4- (Carbazol-9-yl) pyridin-2-yl, 5- (carbazol-9-yl) pyridin-2-yl, 6- (carbazol-9-yl) pyridin-2-yl, 2- (carbazol-9- Yl) pyridin-3-yl, 4- (carbazol-9-yl) pyridin-3-yl, 5- (carbazol-9-yl) pyridin-3-yl, 6- (carbazol-9-yl) pyridine-3 -Yl, 2- (carbazol-9-yl) pyridin-4-yl, 3- (carbazol-9-yl) pyridin-4-yl, 3- (imidazol-1-yl) pyridin-2-yl, 4- (Imi Zol-1-yl) pyridin-2-yl, 5- (imidazol-1-yl) pyridin-2-yl, 6- (imidazol-1-yl) pyridin-2-yl, 2- (imidazol-1-yl) ) Pyridin-3-yl, 4- (imidazol-1-yl) pyridin-3-yl, 5- (imidazol-1-yl) pyridin-3-yl, 6- (imidazol-1-yl) pyridin-3- Yl, 2- (imidazol-1-yl) pyridin-4-yl, 3- (imidazol-1-yl) pyridin-4-yl, 3- (benzo [d] imidazol-1-yl) pyridin-2-yl 4- (benzo [d] imidazol-1-yl) pyridin-2-yl, 5- (benzo [d] imidazol-1-yl) pyridin-2-yl, 6- (benzo [d] imidazol-1- Il) Pyridin-2-yl, 2- (benzo [d] imidazol-1-yl) pyridin-3-yl, 4- (benzo [d] imidazol-1-yl) pyridin-3-yl, 5- (benzo [d ] Imidazol-1-yl) pyridin-3-yl, 6- (benzo [d] imidazol-1-yl) pyridin-3-yl, 2- (benzo [d] imidazol-1-yl) pyridin-4-yl 3- (Benzo [d] imidazol-1-yl) pyridin-4-yl, 3- (1-phenylbenzo [d] imidazol-2-yl) pyridin-2-yl, 4- (1-phenylbenzo [ d] imidazol-2-yl) pyridin-2-yl, 5- (1-phenylbenzo [d] imidazol-2-yl) pyridin-2-yl, 6- (1-phenylbenzo [d] imidazol-2- Il Pyridin-2-yl, 2- (1-phenylbenzo [d] imidazol-2-yl) pyridin-3-yl, 4- (1-phenylbenzo [d] imidazol-2-yl) pyridin-3-yl, 5- (1-phenylbenzo [d] imidazol-2-yl) pyridin-3-yl, 6- (1-phenylbenzo [d] imidazol-2-yl) pyridin-3-yl, 2- (1-phenyl) Benzo [d] imidazol-2-yl) pyridin-4-yl and 3- (1-phenylbenzo [d] imidazol-2-yl) pyridin-4-yl.

Examples of “heteroaryl having 2 to 30 carbon atoms” in which any hydrogen is replaced by silyl include 5-trimethylsilyl-2-thienyl, 5-trimethylsilyl-3-thienyl, 2,5-ditrimethylsilyl-3-thienyl, 3-trimethylsilyl-2-benzothienyl, 2-trimethylsilyl-3-benzothienyl, 6-trimethylsilyl-2-pyridyl, 5-trimethylsilyl-2-pyridyl, 4-trimethylsilyl-2-pyridyl, 3-trimethylsilyl-2-pyridyl, 6-trimethylsilyl-3-pyridyl, 5-trimethylsilyl-3-pyridyl, 4-trimethylsilyl-3-pyridyl, 2-trimethylsilyl-3-pyridyl, 2-trimethylsilyl-4-pyridyl, 3-trimethylsilyl-4-pyridyl, 2- Trimethylsilyl-1-India Le is a 3-trimethylsilyl-9-carbazolyl, 3,6-di-trimethylsilyl-9-carbazolyl, and 9-trimethylsilyl-3-carbazolyl.

Examples of “alkyl” of “optionally substituted alkyl” in R ^{1 to} R ¹⁶ include “alkyl having 1 to 24 carbon atoms”. Examples of “alkyl having 1 to 24 carbon atoms” are the same as those exemplified in the description of the substituent of “aryl”. Arbitrary hydrogen in “C 1-24 alkyl” may be replaced with C 3-12 cycloalkyl, C 6-30 aryl, C 2-30 heteroaryl, or silyl. Examples of the cycloalkyl having 3 to 12 carbon atoms, the aryl having 6 to 30 carbon atoms, the heteroaryl having 2 to 30 carbon atoms, or the silyl group are the same as those exemplified in the description of the above “aryl”.

Examples of “cycloalkyl” of “optionally substituted cycloalkyl” in R ^{1 to} R ¹⁶ include “cycloalkyl having 3 to 12 carbon atoms”. Examples of “cycloalkyl having 3 to 12 carbon atoms” are the same as those exemplified in the description of the substituent of “aryl”. Arbitrary hydrogen of "C3-C12 cycloalkyl" is C1-C24 alkyl, C3-C12 cycloalkyl, C6-C30 aryl, C2-C30 heteroaryl, or It may be replaced by silyl. Examples of alkyl having 1 to 24 carbon atoms, cycloalkyl having 3 to 12 carbon atoms, aryl having 6 to 30 carbon atoms, heteroaryl having 2 to 30 carbon atoms, or silyl are the groups described in the description of the above “aryl”. It is illustrated as well.

2. Specific examples of benzo [a] carbazole compounds represented by formula (1) Specific examples of the compounds of the present invention are shown by the formulas listed below, but the present invention discloses disclosure of these specific structures. It is not limited by. Specific examples of the compound represented by the formula (1) include compounds represented by the following formulas (1-1) to (1-50). Among them, the formulas (1-1) to (1-5), (1-11), (1-12), (1-15) to (1-17), (1-27) to (1-37) , (1-52), and (1-53) are preferable, and the compounds represented by the formulas (1-1) to (1-5), the formulas (1-15) to (1-17), and the formula ( The compounds represented by 1-35) to (1-37) are more preferable.

3. Method for producing benzo [a] carbazole compound represented by formula (1) The benzocarbazole compound represented by formula (1) can be produced by using a known synthesis method. For example, it can be synthesized by following the routes shown in the following reactions 1 to 3.

まず反応１では、パラジウム触媒または銅触媒を用いて、塩基および反応促進剤の存在下、１１Ｈ−ベンゾ［ａ］カルバゾールにＡｒの臭化物またはヨウ化物を反応させて、１１位にＡｒを付ける。ここでＡｒは前記と同じである。１１Ｈ−ベンゾ［ａ］カルバゾールはＳｙｎｌｅｔｔ，Ｎｏ．７，２００６，ｐｐ１０２１−１０２２の記載を参照して製造することができる。

First, in Reaction 1, 11H-benzo [a] carbazole is reacted with a bromide or iodide of Ar in the presence of a base and a reaction accelerator using a palladium catalyst or a copper catalyst, and Ar is attached to the 11-position. Here, Ar is the same as described above. 11H-benzo [a] carbazole is described in Synlett, No. 1; 7, 2006, pp1021-1022.

続いて反応２では、常法に従って置換ベンゾ［ａ］カルバゾールの５、８位を臭素化またはヨウ素化する。

Subsequently, in Reaction 2, the substituted benzo [a] carbazole is brominated or iodinated according to a conventional method.

２つのカルバゾリルが同一である式（１）の化合物を得るためには、反応３で、再びパラジウム触媒または銅触媒を用いて、塩基および反応促進剤の存在下、置換ベンゾ［ａ］カルバゾールの臭化物またはヨウ化物に２倍モルのカルバゾールを反応させて、本発明の式（１）で表される化合物を製造する。式中のＡｒおよびＲ^１〜Ｒ^１６は前記と同じである。

In order to obtain a compound of formula (1) in which two carbazolyls are identical, the bromide of a substituted benzo [a] carbazole in reaction 3 again using a palladium catalyst or a copper catalyst in the presence of a base and a reaction accelerator. Alternatively, the compound represented by the formula (1) of the present invention is produced by reacting iodide with 2 moles of carbazole. Ar and R ^{1 to} R ¹⁶ in the formula are the same as described above.

Further, in order to obtain a compound of the formula (1) in which different carbazolyls are linked, the reaction 3 is carried out in two steps, and different carbazole compounds are reacted in the same molar amount with each substrate in each step. At this time, in the first stage reaction, the 8-position of benzo [a] carbazole is less susceptible to the steric hindrance of the condensed benzene ring than the 5-position, and relaxed reaction conditions (for example, low temperature, weak alkaline atmosphere, etc.) Carbazolyl can be preferentially linked to the 8-position.

When a copper catalyst is used in Reaction 1 and Reaction 3, copper powder, copper oxide, copper halide or the like is used as the catalyst. The base used is potassium carbonate, sodium carbonate, sodium hydrogen carbonate, sodium hydride or the like, and the reaction accelerator is crown ether (for example, 18-crown-6-ether), polyethylene glycol (PEG), polyethylene glycol dialkyl ether. (PEGDM) and the like. As the reaction solvent, N, N-dimethylformamide, nitrobenzene, dimethyl sulfoxide, dichlorobenzene, quinoline and the like are used. The reaction temperature is 160 to 250 ° C., but if the substrate has low reactivity, a higher temperature reaction may be performed using an autoclave or the like.

When a palladium catalyst is used in Reaction 1 and Reaction 3, palladium acetate, palladium chloride, palladium bromide, tris (dibenzylideneacetone) dipalladium (0), tris (dibenzylideneacetone) dipalladium chloroform complex (0), Tetrakis (triphenylphosphine) palladium (0) or the like is used as the catalyst. The base used is lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, sodium hydrogen carbonate, sodium hydride, alkoxy potassium (for example, methoxy potassium, ethoxy potassium, normal propoxy potassium, isopropoxy potassium, n-butoxy Potassium and tert-butoxy potassium, etc.) alkoxy sodium (for example, methoxy sodium, ethoxy sodium, normal propoxy sodium, isopropoxy sodium, n-butoxy sodium and tert-butoxy sodium, etc.)). The reaction accelerator is 2,2 ′-(diphenylphosphino) -1,1′-binaphthyl, 1,1 ′-(diphenylphosphino) ferrocene, dicyclohexylphosphinobiphenyl, di-tert-butylphosphinobiphenyl, tri ( tert-butyl) phosphine, 1- (N, N-dimethylaminomethyl) -2- (di-tert-butylphosphino) ferrocene, 1- (N, N-dibutylaminomethyl) -2- (di-tert- Butylphosphino) ferrocene, 1- (methoxymethyl) -2- (di-tert-butylphosphino) ferrocene, 1,1′-bis (di-tert-butylphosphino) ferrocene, 2,2′-bis ( Di-tert-butylphosphino) -1,1′-binaphthyl, 2-methoxy-2 ′-(di-tert-butylphosphino) -1,1'-binaphthyl and the like are used. An aromatic hydrocarbon solvent such as benzene, toluene, xylene, mesitylene or the like is used as the reaction solvent. A solvent may be used independently and may be used as a mixed solvent. The reaction temperature is usually 50 to 200 ° C., more preferably 80 to 140 ° C.

In the bromination reaction in Reaction 2, the brominating agent is not particularly limited, and examples thereof include bromine, N-bromosuccinimide, copper bromide, benzyltrimethylammonium tribromide, and N-bromosuccinimide is preferably used. As the reaction solvent, N, N-dimethylformamide, N, N-dimethylacetamide, dichloromethane, chloroform, carbon tetrachloride, acetonitrile, acetic acid, sulfuric acid and the like are used. A solvent may be used independently and may be used as a mixed solvent. The reaction temperature is usually in the range of 0 ° C to 150 ° C, more preferably 20 to 100 ° C.

In the iodination reaction in Reaction 2, the iodinating agent is not particularly limited, and examples thereof include potassium iodide and potassium iodate, N-iodosuccinimide, benzyltrimethylammonium dichloroiodate, and N-iodosuccinimide is preferable. Used. As the reaction solvent, N, N-dimethylformamide, N, N-dimethylacetamide, dichloromethane, chloroform, carbon tetrachloride, acetonitrile, acetic acid, sulfuric acid and the like are used. A solvent may be used independently and may be used as a mixed solvent. The reaction temperature is usually in the range of 0 ° C to 150 ° C, more preferably 20 to 100 ° C.

Since the benzo [a] carbazole compound represented by the formula (1) has an asymmetric molecular structure, it is easy to form an amorphous state when manufacturing an organic EL device. In addition, it has excellent heat resistance and is stable when an electric field is applied.

Benzo [a] carbazole compound represented by the formula (1) is effective as the host materials. Benzo [a] carbazole compound represented by the formula (1), the emission wavelength is short, but it can also be used as a fluorescent blue host materials, in particular, benzo carbazole of the formula (1) The compound is effective as a green phosphorescent host material because of its high triplet state energy level (T1). When used as a host material for a green phosphorescent element, energy transfer to the green dopant is efficiently performed, and a phosphorescent light emitting element with high efficiency and long life can be obtained.

If the hydrogen at the 5th and 8th positions of the benzo [a] carbazole basic skeleton is substituted with aryl, phosphorescence emission tends to shift long wavelength and becomes unsuitable for a green phosphorescent host material, but when substituted with 9-carbazolyl The emission wavelength of green phosphorescence derived from benzo [a] carbazole can be maintained without causing a long wavelength shift.

The phosphorescence wavelength of the benzo [a] carbazole compound represented by the formula (1) can be controlled by the number of substituents. In particular, when the number of substituents is small, green phosphorescence having a short phosphorescence wavelength and good color purity can be emitted with high efficiency. That is, from benzo [a] carbazole compound substituents R ¹ to R ¹⁶ are better for all benzo [a] carbazole compound is hydrogen substituted of formula (1), is excellent as a green phosphorescent host materials. For example, benzo [a] carbazole compound represented by the formula (1-1) is particularly excellent as green phosphorescent host materials.

Further, the benzo [a] carbazole compound represented by the formula (1) can control the intermolecular interaction depending on the number and type of substituents. Specifically, nonradiative deactivation can be suppressed and light can be emitted with high efficiency. Furthermore, the compound of the present invention is suitable for fluorescent blue host materials and red phosphorescent host materials by controlling the fluorescence or phosphorescence wavelength depending on the number of substituents.

The benzo [a] carbazole compound represented by the formula (1) exhibits a stable glass state, and can form a stable amorphous film by vapor deposition or the like. Moreover, the solubility with respect to an organic solvent is large, and not only recrystallization and purification by column chromatography are easy, but also a free layer forming means can be employed when forming a layer of a light emitting element. For example, in general, in the layer formation by vapor deposition, there is a risk of decomposition of the compound or non-uniformity of the crystal structure of the formed layer, but the spin coating method is easily adopted using various solvents. Therefore, it is possible to form a layer that eliminates these fears.

4). Organic electroluminescent device The benzo [a] carbazole compound according to the present invention can be used, for example, as a material for an organic EL device.

<Structure of organic EL element>
Although the structure of the organic EL device of the present invention has various modes, it is basically a multilayer structure in which at least a hole transport layer, a light emitting layer, and an electron transport layer are sandwiched between an anode and a cathode. Examples of the specific configuration of the device are (1) anode / hole transport layer / light emitting layer / electron transport layer / cathode, (2) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer. / Cathode, (3) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode, (4) anode / hole injection layer / hole transport layer / light emitting layer / positive Hole blocking layer / electron transport layer / electron injection layer / cathode, etc.

<Light emitting layer>
Since the light emitting material of the present invention has high light emission quantum efficiency, hole injection property, hole transport property, electron injection property and electron transport property, it can be effectively used as a light emitting material in a light emitting layer. The organic EL device of the present invention can form a light emitting layer only with the compound of the present invention. The organic EL device of the present invention can improve the light emission luminance and the light emission efficiency by combining the light emitting material of the present invention with another light emitting material, and can obtain blue, green, red and white light emission. At this time, the organic EL device of the present invention preferably uses the compound of the present invention as a host.

Other light-emitting materials that can be used in the light-emitting layer together with the compound of the present invention are described in Toray Research Center, Research Division, “Frontiers of Full-scale Practical Use of Organic EL Display”, Asahi High Speed Printing Co., Ltd. (2002) P125-132. Luminescent materials as described, such as described in P170-172, supervised by Shinji Kido, “Organic EL materials and displays”, published by CMMC (2001) P153-156. Triplet materials and the like.

Compounds that can be used as other light-emitting materials are polycyclic aromatic compounds, heteroaromatic compounds, organometallic complexes, dyes, polymer-based light-emitting materials, styryl derivatives, coumarin derivatives, borane derivatives, oxazine derivatives, compounds having a spiro ring Oxadiazole derivatives, fluorene derivatives and the like. Examples of the polycyclic aromatic compound are anthracene derivatives, phenanthrene derivatives, naphthacene derivatives, pyrene derivatives, chrysene derivatives, perylene derivatives, coronene derivatives, rubrene derivatives, and the like. Examples of heteroaromatic compounds are oxadiazole derivatives having a dialkylamino group or diarylamino group, pyrazoloquinoline derivatives, pyridine derivatives, pyran derivatives, phenanthroline derivatives, silole derivatives, thiophene derivatives having a triphenylamino group, quinacridone derivatives Etc. Examples of organometallic complexes are zinc, aluminum, beryllium, europium, terbium, dysprosium, iridium, platinum, rhenium, osmium, silver, gold, etc., quinolinol derivatives, benzoxazole derivatives, benzothiazole derivatives, oxadiazole derivatives, A complex with a thiadiazole derivative, a phenylpyridine derivative, a phenylbenzimidazole derivative, a pyrrole derivative, a pyridine derivative, a phenanthroline derivative, or the like. Examples of dyes are xanthene derivatives, polymethine derivatives, porphyrin derivatives, coumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, oxobenzanthracene derivatives, carbostyril derivatives, perylene derivatives, benzoxazole derivatives, benzothiazole derivatives, benzimidazoles And pigments such as derivatives. Examples of the polymer light-emitting material include polyparaphenyl vinylene derivatives, polythiophene derivatives, polyvinyl carbazole derivatives, polysilane derivatives, polyfluorene derivatives, polyparaphenylene derivatives, and the like. Examples of styryl derivatives are amine-containing styryl derivatives, styrylarylene derivatives, and the like.

A known compound can be used as the light-emitting dopant when the compound of the present invention is used as a host, and can be selected from various materials according to a desired emission color. Specific examples include amines having a stilbene structure, aromatic amines, perylene derivatives, coumarin derivatives, borane derivatives, pyran derivatives, iridium complexes, platinum complexes, and rhenium complexes. Among them, a green phosphorescent dopant material of iridium complex, platinum complex or rhenium complex is preferable.

Examples of the iridium complex include tris (2-phenylpyridine) iridium (III) :( Ir (ppy) ₃ ), tris (2- (4-tolyl) pyridine) iridium (III) :( Ir (mppy) ₃ ), bis (2-Phenylpyridine) acetylacetonatoiridium (III) :( Ir (ppy) ₂ (acac)), bis (2-phenylpyridine) (1-phenylpyrazole) iridium (III) :( Ir (ppy) ₂ ( ppz)) and the like.

Examples of platinum complexes include 3,3 ′-(6,6 ′-(propane-2,2-diyl) bis (pyridine-6,2-diyl)) dibenzonitrile platinum: (Pt-1), bis (2- (3-tert-butylpyrazol-5-yl) pyridine) platinum: (Pt-2), bis (2- (3-tert-butyl-1,2,4-triazol-5-yl) pyridine) platinum: ( Pt-3) and the like.

Examples of the rhenium complex include Re-1 below.

Other dopants can be appropriately selected and used from the compounds described in Chemical Industry, June 2004, page 13, and references cited therein.

<Electron transport layer / electron injection layer>
The electron transport material and electron injection material used in the organic EL device of the present invention can be selected from compounds that can be used as an electron transfer compound in a photoconductive material and compounds that can be used in an electron injection layer and an electron transport layer of an organic EL device. Can be selected and used.

Examples of such electron transfer compounds are benzimidazole derivatives, quinolinol-based metal complexes, pyridine derivatives, phenanthroline derivatives, diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives, thiophene derivatives, triazole derivatives, thiadiazole derivatives, oxine derivative metals. Complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives, imidazopyridine derivatives, and borane derivatives.

Preferred examples of the electron transfer compound are benzimidazole derivatives, quinolinol metal complexes, pyridine derivatives, or phenanthroline derivatives. Of these, benzimidazole derivatives are more preferable.

式中、Ａｒ^１〜Ａｒ^３はそれぞれ独立に水素または置換されていてもよい炭素数６〜３０のアリールである。特に、Ａｒ^１が置換されていてもよいアントリルであるベンゾイミダゾール誘導体が好ましい。 The benzimidazole derivative is a compound represented by the following formula (E-1).

In the formula, Ar ^{1 to} Ar ³ are each independently hydrogen or optionally substituted aryl having 6 to 30 carbon atoms. In particular, a benzimidazole derivative that is anthryl optionally substituted with Ar ¹ is preferable.

Specific examples of the aryl having 6 to 30 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, acenaphthylene-1-yl, acenaphthylene-3-yl, acenaphthylene-4-yl, acenaphthylene-5-yl, and fluorene-1- Yl, fluoren-2-yl, fluoren-3-yl, fluoren-4-yl, fluoren-9-yl, phenalen-1-yl, phenalen-2-yl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, 1-anthryl, 2-anthryl, 9-anthryl, fluoranthen-1-yl, fluoranthen-2-yl, fluoranthen-3-yl, fluoranthen-7-yl, fluoranthen-8-yl, Triphenylene-1-yl, triphenylene-2-yl, pyreth -1-yl, pyren-2-yl, pyren-4-yl, chrysen-1-yl, chrysen-2-yl, chrysen-3-yl, chrysen-4-yl, chrysen-5-yl, chrysene-6 -Yl, naphthacene-1-yl, naphthacene-2-yl, naphthacene-5-yl, perylene-1-yl, perylene-2-yl, perylene-3-yl, pentacene-1-yl, pentasen-2-yl , Pentacene-5-yl and pentacene-6-yl.

Specific examples of the benzimidazole derivative include 1-phenyl-2- (4- (10-phenylanthracen-9-yl) phenyl) -1H-benzo [d] imidazole, 2- (4- (10- (naphthalene-2) -Yl) anthracen-9-yl) phenyl) -1-phenyl-1H-benzo [d] imidazole, 2- (3- (10- (naphthalen-2-yl) anthracen-9-yl) phenyl) -1- Phenyl-1H-benzo [d] imidazole, 5- (10- (naphthalen-2-yl) anthracen-9-yl) -1,2-diphenyl-1H-benzo [d] imidazole, 1- (4- (10 -(Naphthalen-2-yl) anthracen-9-yl) phenyl) -2-phenyl-1H-benzo [d] imidazole, 2- (4- (9,10-di (naphthalene) 2-yl) anthracen-2-yl) phenyl) -1-phenyl-1H-benzo [d] imidazole, 1- (4- (9,10-di (naphthalen-2-yl) anthracen-2-yl) phenyl ) -2-Phenyl-1H-benzo [d] imidazole and 5- (9,10-di (naphthalen-2-yl) anthracen-2-yl) -1,2-diphenyl-1H-benzo [d] imidazole It is.

Specific examples of the quinolinol-based metal complex include tris (8-quinolinolato) aluminum (hereinafter abbreviated as ALQ), tris (4-methyl-8-quinolinolato) aluminum, tris (5-methyl-8-quinolinolato) aluminum, Tris (3,4-dimethyl-8-quinolinolato) aluminum, tris (4,5-dimethyl-8-quinolinolato) aluminum, tris (4,6-dimethyl-8-quinolinolato) aluminum, bis (2-methyl-8- Quinolinolato) (phenolate) aluminum, bis (2-methyl-8-quinolinolato) (2-methylphenolato) aluminum, bis (2-methyl-8-quinolinolato) (3-methylphenolato) aluminum, bis (2-methyl) -8-quinolinolato) (4-methyl Enolate) aluminum, bis (2-methyl-8-quinolinolato) (2-phenylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (3-phenylphenolato) aluminum, bis (2-methyl-8- Quinolinolato) (4-phenylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,3-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,6-dimethylphenolate) ) Aluminum, bis (2-methyl-8-quinolinolato) (3,4-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (3,5-dimethylphenolate) aluminum, bis (2-methyl) -8-quinolinolate) (3,5-di-tert- Tylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,6-diphenylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,4,6-triphenylphenolate) aluminum Bis (2-methyl-8-quinolinolato) (2,4,6-trimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,4,5,6-tetramethylphenolato) aluminum, Bis (2-methyl-8-quinolinolato) (1-naphtholato) aluminum, bis (2-methyl-8-quinolinolato) (2-naphtholato) aluminum, bis (2,4-dimethyl-8-quinolinolato) (2-phenyl) Phenolate) aluminum, bis (2,4-dimethyl-8-quinolinola) G) (3-phenylphenolate) aluminum, bis (2,4-dimethyl-8-quinolinolato) (4-phenylphenolato) aluminum, bis (2,4-dimethyl-8-quinolinolato) (3,5-dimethyl) Phenolate) aluminum, bis (2,4-dimethyl-8-quinolinolato) (3,5-di-tert-butylphenolate) aluminum, bis (2-methyl-8-quinolinolato) aluminum-μ-oxo-bis ( 2-methyl-8-quinolinolato) aluminum, bis (2,4-dimethyl-8-quinolinolato) aluminum-μ-oxo-bis (2,4-dimethyl-8-quinolinolato) aluminum, bis (2-methyl-4- Ethyl-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-4-ethyl) Ru-8-quinolinolato) aluminum, bis (2-methyl-4-methoxy-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-4-methoxy-8-quinolinolato) aluminum, bis (2-methyl- 5-cyano-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-5-cyano-8-quinolinolato) aluminum, bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum-μ- Oxo-bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum, bis (10-hydroxybenzo [h] quinoline) beryllium, and 8-quinolinolatolithium.

Specific examples of pyridine derivatives are 2,5-bis (2,2′-bipyridyl-6-yl) -1,1-dimethyl-3,4-diphenylsilole, 2,5-bis (2,2′-bipyridyl). -6-yl) -1,1-dimethyl-3,4-dimesitylsilole, 9,10-di (2,2′-bipyridyl-6-yl) anthracene, 9,10-di (2,2 ′) -Bipyridyl-5-yl) anthracene, 9,10-di (2,3'-bipyridyl-6-yl) anthracene, 9,10-di (2,3'-bipyridyl-5-yl) -2-phenylanthracene 9,10-di (2,2′-bipyridyl-5-yl) -2-phenylanthracene, 3,4-diphenyl-2,5-di (2,2′-bipyridyl-6-yl) thiophene, 3, , 4-Diphenyl-2,5-di (2,3′-bipyri -5-yl) thiophene, and 6'6 "- di (2-pyridyl) 2,2 ': 4', 4": 2 ", 2" '- a quaterphenyl pyridine.

Specific examples of phenanthroline derivatives include 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 9,10-di (1,10-phenanthroline-2 -Yl) anthracene, 2,6-di (1,10-phenanthroline-5-yl) pyridine, 1,3,5-tri (1,10-phenanthroline-5-yl) benzene, 9,9'-difluoro- Bis (1,10-phenanthroline-5-yl), bathocuproin, and 1,3-bis (2-phenyl-1,10-phenanthroline-9-yl) benzene.

<Hole blocking layer>
The hole blocking layer serves to confine holes and electrons in the light emitting layer and improve the light emission efficiency. The hole blocking layer is preferably a substance that prevents holes moving from the anode from reaching the cathode and efficiently transports electrons injected from the cathode toward the light emitting layer. That is, the material for forming the hole blocking layer is required to have a property of high electron mobility and low hole mobility in order to improve luminous efficiency. In addition, high driving stability is also required from the demand for extending the life of organic electroluminescent elements.

Specifically, organometallic complexes (mixed ligand complexes, binuclear metal complexes, etc.), styryl compounds (distyryl biphenyl derivatives, etc.), triazole derivatives, phenanthroline derivatives, borane derivatives, and anthracene derivatives (for example, JP-A 2006-2006 No. 049570) and the like. These materials can be used alone or in combination with different materials.

Among these, organometallic complexes (mixed ligand complexes, binuclear metal complexes, etc.), phenanthroline derivatives, or borane derivatives are preferable.

Specific examples of organometallic complexes (mixed ligand complexes, binuclear metal complexes, etc.) include bis (2-methyl-8-quinolinolato) (phenolate) aluminum, bis (2-methyl-8-quinolinolato) (2-methyl Phenolate) aluminum, bis (2-methyl-8-quinolinolato) (3-methylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (4-methylphenolate) aluminum, bis (2-methyl-8) -Quinolinolato) (2-phenylphenolato) aluminum, bis (2-methyl-8-quinolinolato) (3-phenylphenolato) aluminum, bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum ( Hereinafter, abbreviated as Balq), bis (2-methyl-8-quinolinolate). (2,3-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,6-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (3,4-dimethylphenolate) ) Aluminum, bis (2-methyl-8-quinolinolato) (3,5-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (3,5-di-tert-butylphenolato) aluminum, bis (2-methyl-8-quinolinolato) (2,4-diphenylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (2,5-diphenylphenolato) aluminum, bis (2-methyl-8-quinolinolato) ) (2,6-diphenylphenolate) aluminum, bis (2-methyl) Ru-8-quinolinolate) (2,4,6-triphenylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (2,4,6-trimethylphenolate) aluminum, bis (2-methyl-8) -Quinolinolato) (2,4,5,6-tetramethylphenolate) aluminum, bis (2-methyl-8-quinolinolato) (1-naphtholato) aluminum, bis (2-methyl-8-quinolinolato) (2-naphtholate) ) Aluminum, bis (2,4-dimethyl-8-quinolinolato) (2-phenylphenolate) aluminum, bis (2,4-dimethyl-8-quinolinolato) (3-phenylphenolato) aluminum, bis (2,4 -Dimethyl-8-quinolinolate) (4-phenylphenolate) aluminum, Bis (2,4-dimethyl-8-quinolinolato) (3,5-dimethylphenolate) aluminum, bis (2,4-dimethyl-8-quinolinolato) (3,5-di-tert-butylphenolate) aluminum, Bis (2-methyl-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-8-quinolinolato) aluminum, bis (2,4-dimethyl-8-quinolinolato) aluminum-μ-oxo-bis (2, 4-dimethyl-8-quinolinolato) aluminum, bis (2-methyl-4-ethyl-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-4-ethyl-8-quinolinolato) aluminum, bis (2- Methyl-4-methoxy-8-quinolinolate) aluminum-μ-oxo-bis (2-methyl) -4-methoxy-8-quinolinolato) aluminum, bis (2-methyl-5-cyano-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-5-cyano-8-quinolinolato) aluminum, and bis ( 2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum.

Specific examples of the phenanthroline derivative include 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (hereinafter abbreviated as BCP), 2,4,9 , 7-tetraphenyl-1,10-phenanthroline, 9,10-di (1,10-phenanthrolin-2-yl) anthracene, 2,6-di (1,10-phenanthroline-5-yl) pyridine, 1, 3,5-tri (1,10-phenanthroline-5-yl) benzene and 1,3-bis (2-phenyl-1,10-phenanthroline-9-yl) benzene.

Specific examples of the borane derivatives are 9- (4′-dimesitylborylbiphenyl-4-yl) -9H-carbazole, 9- (4- (4-dimesitylborylnaphthalen-1-yl) phenyl) -9H. -Carbazole, 9- (4- (4-dimesitylborylphenyl) naphthalen-1-yl) -9H-carbazole, 9- (4- (6-dimesitylborylnaphthalen-2-yl) phenyl) -9H -Carbazole, 9- (6- (4-Dimesitylborylphenyl) naphthalen-2-yl) -9H-carbazole, 9- (7-Dimesitylboryl-9,9-dimethyl-9H-fluoren-2-yl)- 9H-carbazole, 9- (7-dimesitylboryl-9,9-diphenyl-9H-fluoren-2-yl) -9H-carbazole, 4,4′-bis (dimesitylboryl) Biphenyl, 1-dimesitylboryl-4- (4-dimesitylborylphenyl) naphthalene, 2-dimesitylboryl-6- (4-dimesitylborylphenyl) naphthalene, 2,7-bis (dimesitylboryl) -9,9-dimethyl -9H-fluorene and 2,7-bis (dimesitylboryl) -9,9-diphenyl-9H-fluorene. Further, a borane derivative described in Japanese Patent Application No. 2005-210638 may be used.

<Hole transport layer / hole injection layer>
Regarding the hole injection material and the hole transport material used in the organic EL device of the present invention, in a photoconductive material, a compound conventionally used as a charge transport material for holes or a hole injection of an organic EL device is used. Any known material used for the layer and the hole transport layer can be selected and used. Examples thereof are carbazole derivatives, triarylamine derivatives, phthalocyanine derivatives. Examples of the carbazole derivative are N-phenylcarbazole and polyvinylcarbazole. Examples of triarylamine derivatives are polymers having an aromatic tertiary amine in the main chain or side chain, 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane, N, N′-diphenyl-N , N′-di (3-methylphenyl) -4,4′-diaminobiphenyl, N, N′-diphenyl-N, N′-dinaphthyl-4,4′-diaminobiphenyl (hereinafter abbreviated as NPD) 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine, a starburst amine derivative. Examples of phthalocyanine derivatives are metal-free phthalocyanine and copper phthalocyanine. .

<Method for producing organic EL element>
Each layer constituting the organic EL element of the present invention can be formed by forming a material to constitute each layer into a thin film by a method such as a vapor deposition method, a spin coating method, or a casting method. The thickness of each layer formed in this way is not particularly limited and can be appropriately set according to the properties of the material, but is usually in the range of 2 nm to 5000 nm. Note that it is preferable to employ a vapor deposition method as a method of thinning the light emitting material from the standpoint that a homogeneous film can be easily obtained and pinholes are hardly generated. When a thin film is formed by using a vapor deposition method, the vapor deposition conditions vary depending on the type of the light emitting material of the present invention, the target crystal structure and associated structure of the molecular accumulation film, and the like. Deposition conditions generally include boat heating temperature +50 to + 400 ° C., vacuum degree 10 ⁻⁶ to 10 ⁻³ Pa, deposition rate 0.01 to 50 nm / second, substrate temperature −150 to + 300 ° C., film thickness 5 nm to 5 μm. It is preferable to set appropriately within the range.

The organic EL device of the present invention is preferably supported by a substrate in any of the structures described above. The substrate only needs to have mechanical strength, thermal stability, and transparency, and glass, a transparent plastic film, and the like can be used. As the anode material, metals, alloys, electrically conductive compounds and mixtures thereof having a work function larger than 4 eV can be used. Examples thereof are metals such as Au, CuI, indium tin oxide (hereinafter abbreviated as ITO), SnO ₂ , ZnO, and the like.

Cathode materials can use metals, alloys, electrically conductive compounds, and mixtures thereof with work functions of less than 4 eV. Examples thereof are aluminum, calcium, magnesium, lithium, magnesium alloy, aluminum alloy and the like. Examples of alloys are aluminum / lithium fluoride, aluminum / lithium, magnesium / silver, magnesium / indium and the like. In order to efficiently extract light emitted from the organic EL element, it is desirable that at least one of the electrodes has a light transmittance of 10% or more. The sheet resistance as the electrode is preferably several hundred Ω / □ or less. Although the film thickness depends on the properties of the electrode material, it is usually set in the range of 10 nm to 1 μm, preferably 10 to 400 nm. Such an electrode can be produced by forming a thin film by a method such as vapor deposition or sputtering using the electrode material described above.

Next, as an example of a method for producing an organic EL device using the light emitting material of the present invention, the aforementioned anode / hole injection layer / hole transport layer / light emitting material of the present invention + dopant (light emitting layer) / electron transport. A method for producing an organic EL element comprising a layer / cathode will be described. A thin film of an anode material is formed on a suitable substrate by vapor deposition to produce an anode, and then a thin film of a hole injection layer and a hole transport layer is formed on the anode. A thin film is formed by co-evaporating the light-emitting material and dopant of the present invention on this to form a light-emitting layer, an electron transport layer is formed on the light-emitting layer, and a thin film made of a cathode material is formed by vapor deposition. By using the cathode, the target organic EL device can be obtained. In the production of the organic EL element described above, the production order can be reversed, and the cathode, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode can be produced in this order.

When a DC voltage is applied to the organic EL device thus obtained, the anode may be applied with a positive polarity and the cathode with a negative polarity. When a voltage of about 2 to 40 V is applied, a transparent or translucent electrode is applied. Luminescence can be observed from the side (anode or cathode, and both). The organic EL element also emits light when an alternating voltage is applied. The alternating current waveform to be applied may be arbitrary.

The present invention will be described in more detail based on examples.
Synthesis Example 1 Synthesis of Compound (1-1) Compound (1-1): 5,8-di (carbazol-9-yl) -11-phenylbenzo [a] carbazole was synthesized by the following reaction.

Ｓｙｎｌｅｔｔ，Ｎｏ．７，２００６，ｐｐ１０２１−１０２２の記載に従って合成した１１Ｈ−ベンゾ［ａ］カルバゾール６．５２ｇとブロモベンゼン５．６５ｇを、窒素雰囲気下脱水キシレン１５０ｍｌに溶解させ、酢酸パラジウム０．３４ｇ、炭酸カリウム１２．４４ｇ、そしてトリ（ｔｅｒｔ−ブチル）ホスフィン０．９１を加えて８時間還流した。反応後水を１００ｍｌ加えて撹拌し、分液後有機層を水洗した。有機層をロータリーエバポレーターにて濃縮し、得られた粗製品をシリカゲルでカラム精製（溶媒：へプタン／トルエン＝３／１（容積比））を行って、中間体の化合物（１−１ａ）：１１−フェニルベンゾ［ａ］カルバゾール７．２ｇ（収率：８２％）を得た。 <Synthesis of 11-phenylbenzo [a] carbazole>

Synlett, No. 1; No. 7,2006, pp1021-11022, 6.52 g of 11H-benzo [a] carbazole and 5.65 g of bromobenzene were dissolved in 150 ml of dehydrated xylene under a nitrogen atmosphere, 0.34 g of palladium acetate, and 12.1 of potassium carbonate. 44 g and 0.91 of tri (tert-butyl) phosphine were added and refluxed for 8 hours. After the reaction, 100 ml of water was added and stirred, and after liquid separation, the organic layer was washed with water. The organic layer is concentrated with a rotary evaporator, and the resulting crude product is subjected to column purification with silica gel (solvent: heptane / toluene = 3/1 (volume ratio)) to obtain an intermediate compound (1-1a): Thus, 7.2 g of 11-phenylbenzo [a] carbazole was obtained (yield: 82%).

中間体化合物（１−１ａ）５．４５ｇとＮ−ヨードスクシンイミド（ＮＩＳ）８．３６ｇを、窒素雰囲気下ジクロロメタン５６ｍｌに溶解させ、酢酸３７ｍｌを加えて、室温で１５時間攪拌した。その後、Ｎ−ヨードスクシンイミド（ＮＩＳ）２．１ｇを追加して、さらに室温で９時間攪拌した。反応後水を１００ｍｌ添加し、溶媒を減圧留去した後、析出した固体をろ別して粗製品を得た。その粗製品をシリカゲルでカラム精製（溶媒：トルエン）を行った後、中間体の化合物（１−１ｂ）：５，８−ジヨード−１１−フェニルベンゾ［ａ］カルバゾール９．５ｇ（収率：９４％）を得た。 <Synthesis of 5,8-diiodo-11-phenylbenzo [a] carbazole>

Intermediate compound (1-1a) 5.45 g and N-iodosuccinimide (NIS) 8.36 g were dissolved in 56 ml of dichloromethane under a nitrogen atmosphere, 37 ml of acetic acid was added, and the mixture was stirred at room temperature for 15 hours. Thereafter, 2.1 g of N-iodosuccinimide (NIS) was added, and the mixture was further stirred at room temperature for 9 hours. After the reaction, 100 ml of water was added, the solvent was distilled off under reduced pressure, and the precipitated solid was separated by filtration to obtain a crude product. The crude product was subjected to column purification with silica gel (solvent: toluene), and then intermediate compound (1-1b): 9.5 g of 5,8-diiodo-11-phenylbenzo [a] carbazole (yield: 94). %).

窒素雰囲気下、中間体化合物（１−１ｂ）５．４５ｇ、カルバゾール４．１８ｇ、銅粉２．５４ｇ、炭酸カリウム１１．０６ｇ、１８−クラウン−６エーテル（１８−Ｃ−６）０．２１ｇ、およびｏ−ジクロロベンゼン５０ｍｌをフラスコに入れて、１８０℃で１４時間還流した。反応液を冷却し、ろ過して固体を除去した後、ろ液を減圧濃縮した。得られた固形物をメタノールで洗浄し、化合物（１−１）：５，８−ジ（カルバゾール−９−イル）−１１−フェニルベンゾ［ａ］カルバゾールの粗製品を得た。その粗製品をシリカゲルでカラム精製（溶媒：へプタン／トルエン＝３／１（容積比））を行い、さらにトルエン／イソプロピルアルコール（１／２（容積比））から再結晶した後、昇華精製して、目的の化合物（１−１）２．５ｇ（収率：４０．１％）を得た。ＭＳスペクトルおよびＮＭＲ測定により化合物（１−１）の構造を確認した。
^１Ｈ−ＮＭＲ（ＣＤＣｌ_３）： σ＝８．３７（ｓ，１Ｈ）、８．２７（ｄ，１Ｈ）、８．２３〜８．１４（ｍ，４Ｈ）、７．８１〜７．７３（ｍ，５Ｈ）、７．６３〜７．６１（ｍ，１Ｈ）、７．５８〜７．５６（ｍ，１Ｈ）、７．４３〜７．２６（ｍ，１４Ｈ）、７．０８（ｓ，１Ｈ）、７．０６（ｄ，１Ｈ）．
その他の物性は以下の通りであった。
ガラス転移温度（Ｔｇ）：１８２℃ ［測定機器：Diamond DSC （PERKIN−ELMER社製）； 測定条件： 冷却速度200℃／Min.、昇温速度10℃／Min.］ <Synthesis of 5,8-di (carbazol-9-yl) -11-phenylbenzo [a] carbazole>

Under nitrogen atmosphere, intermediate compound (1-1b) 5.45 g, carbazole 4.18 g, copper powder 2.54 g, potassium carbonate 11.06 g, 18-crown-6 ether (18-C-6) 0.21 g, And 50 ml of o-dichlorobenzene were placed in a flask and refluxed at 180 ° C. for 14 hours. The reaction solution was cooled and filtered to remove the solid, and then the filtrate was concentrated under reduced pressure. The obtained solid was washed with methanol to obtain a crude product of compound (1-1): 5,8-di (carbazol-9-yl) -11-phenylbenzo [a] carbazole. The crude product is subjected to column purification with silica gel (solvent: heptane / toluene = 3/1 (volume ratio)), recrystallized from toluene / isopropyl alcohol (1/2 (volume ratio)), and then purified by sublimation. Thus, 2.5 g (yield: 40.1%) of the target compound (1-1) was obtained. The structure of the compound (1-1) was confirmed by MS spectrum and NMR measurement.
¹ H-NMR (CDCl ₃ ): σ = 8.37 (s, 1H), 8.27 (d, 1H), 8.23 to 8.14 (m, 4H), 7.81 to 7.73 ( m, 5H), 7.63-7.61 (m, 1H), 7.58-7.56 (m, 1H), 7.43-7.26 (m, 14H), 7.08 (s, 1H), 7.06 (d, 1H).
Other physical properties were as follows.
Glass transition temperature (Tg): 182 ° C. [Measuring instrument: Diamond DSC (manufactured by PERKIN-ELMER); Measuring conditions: Cooling rate 200 ° C./Min., Temperature rising rate 10 ° C./Min.]

By appropriately selecting the raw material compound, another benzo [a] carbazole compound of the present invention can be synthesized by a method according to the above synthesis example.

[Synthesis Example 2] Synthesis of Comparative Example Compound (2-1) Comparative Example Compound (2-1): 5,8,11-triphenylbenzo [a] carbazole was synthesized by the following reaction 4.

Under a nitrogen atmosphere, 3.6 g of the intermediate compound (1-1b), 1.77 g of phenylboronic acid, 0.3 g of tetrakis (triphenylphosphine) palladium (0) (Pd (PPh ₃ )), sodium carbonate 2 .8 g and 30 ml of a mixed solvent of toluene and ethanol (toluene / ethanol = 4/1 (volume ratio)) were placed in a flask and stirred for 5 minutes. Then 10 ml of water was added and refluxed for 4 hours. After completion of the heating, the reaction solution was cooled, the organic layer was separated, washed with saturated brine, and dried over anhydrous magnesium sulfate. After removing the desiccant and evaporating the solvent under reduced pressure, the solid obtained was subjected to column purification with silica gel (solvent: heptane / toluene = 4/1 (volume ratio)), and further recrystallized from heptane. Purification by sublimation gave 0.8 g (yield: 27.6%) of the desired compound (2-1): 5,8,11-triphenylbenzo [a] carbazole. The structure of the compound (2-1) was confirmed by MS spectrum and NMR measurement.
¹ H-NMR (CDCl ₃ ): σ = 8.37 (d, 1H), 8.22 (s, 1H), 8.03 (d, 1H), 7.72 to 7.58 (m, 10H) 7.55-7.44 (m, 6H), 7.38-7.32 (m, 2H), 7.25-7.21 (m, 2H).
Other physical properties were as follows.
Glass transition temperature (Tg): 93.5 ° C. [Measuring instrument: Diamond DSC (manufactured by PERKIN-ELMER); Measurement conditions: cooling rate 200 ° C./Min., Heating rate 10 ° C./Min.]

Synthesis Example 3 Synthesis of Comparative Compound (2-2) Comparative Compound (2-2): 5,8-di (m-terphenyl-5′-yl,)-11-phenylbenzo [A] Carbazole was synthesized.

In a nitrogen atmosphere, 2.72 g of the intermediate compound (1-1b), 2.88 g of m-terphenyl-5′-boronic acid, tetrakis (triphenylphosphine) palladium (0) (Pd (PPh ₃ )) 23 g, 2.12 g of sodium carbonate and 50 ml of a mixed solvent of toluene and ethanol (toluene / ethanol = 4/1 (volume ratio)) were placed in a flask and stirred for 5 minutes. Thereafter, 8 ml of water was added and refluxed for 5 hours. After completion of the heating, the reaction solution was cooled, the organic layer was separated, washed with saturated brine, and dried over anhydrous magnesium sulfate. The desiccant was removed, and the solid obtained by distilling off the solvent under reduced pressure was subjected to column purification with silica gel (solvent: heptane / toluene = 3/1 (volume ratio)), and further column purification with activated carbon (solvent: (Toluene), followed by sublimation purification to obtain 1.5 g (yield: 40%) of the desired compound (2-2). The structure of compound (2-2): 5,8-di (m-terphenyl-5′-yl,)-11-phenylbenzo [a] carbazole was confirmed by MS spectrum and NMR measurement.
¹ H-NMR (CDCl ₃ ): σ = 8.51 (d, 1H), 8.37 (s, 1H), 8.19 (d, 1H), 7.92 to 7.57 (m, 21H) 7.50-7.25 (m, 15H).
Other physical properties were as follows.
Glass transition temperature (Tg): 158.1 ° C. [Measuring instrument: Diamond DSC (manufactured by PERKIN-ELMER); Measurement conditions: cooling rate 200 ° C./Min., Temperature rising rate 10 ° C./Min.]

Table 1 below summarizes the physical property values of the compound (1-1), the benzo [a] carbazole compounds (2-1), (2-2), and CBP (manufactured by Dojindo Laboratories). It was shown to. Melting point (Tm), glass transition temperature (Tg) and crystallization temperature (Tc) were measured using a Diamond DSC manufactured by Perkin-Elmer (measuring conditions: cooling rate 200 ° C./min, heating rate 10 ° C./min). Min). The thin film fluorescence maximum wavelength (λmax) was measured using a V-560 spectrophotometer manufactured by JASCO Corporation with an excitation wavelength of 360 nm.

Compound CBP in Table 1 has the following structure.

From this measurement result, it can be expected that the benzo [a] carbazole compound represented by the formula (1) has a stable glass state and forms a stable amorphous film by vapor deposition or the like. Further, when viewed from the film fluorescence maximum wavelength, it is possible that the compounds of the present invention is used as a fluorescent blue host materials.

[Example]
The phosphorescent quantum yield was measured using the above three kinds of benzo [a] carbazole compounds and CBP as a phosphorescent host material and Ir (ppy) ₃ as a phosphorescent green dopant. The measurement was performed according to the description in Japanese Journal of Applied Physics Vol. 43, No. 11A, 2004, pp. 7729-7730.

<Preparation of sample>
A sample for light emission quantum yield measurement was prepared as follows.
A synthetic quartz substrate (10 mm × 10 mm × 0.7 t) was used as the substrate. This substrate was fixed to a substrate holder of a commercially available vapor deposition apparatus. A metal mask was also attached to the substrate holder at the same time so that the diameter of the deposition area was 5 mmφ. A molybdenum vapor deposition boat containing a host material and a molybdenum vapor deposition boat containing a dopant material were mounted on the vapor deposition apparatus. The vacuum chamber is depressurized to 5 × 10 ⁻⁴ Pa, and the molybdenum vapor deposition boat containing the host material and the molybdenum vapor deposition boat containing the dopant material are heated at the same time. A sample for measurement was formed by vapor deposition. At this time, the dopant concentration of the dopant material was about 5% by weight. The deposition rate was 0.01-1 nm / second.

N_emissionは材料から放出されたフォトン数、N_Absorptionは材料が吸収したフォトン数であり、発光量子収率はその比として求められる。ここで、αは測定系の補正係数、λは波長、ｈはプランク定数、ｃは光速、I_em（λ）はサンプルの発光強度、I_ex（λ）はサンプルを設置する前の励起光強度、I'_ex（λ）はサンプルへ励起光を照射した時に観測される励起光強度である。I_emとI'_ex＋I_emの２つのスペクトル観測を行うことで、発光量子収率の測定が可能である。 <Description of measurement method>
According to Japanese Journal of Applied Physics Vol. 43, No. 11A, 2004, pp. 7729-7730., The emission quantum yield η _PL is given by the following equation.

N _emission is the number of photons emitted from the material, N _Absorption is the number of photons absorbed by the material, and the emission quantum yield is obtained as the ratio. Where α is the correction factor of the measurement system, λ is the wavelength, h is the Planck constant, c is the speed of light, I _em (λ) is the emission intensity of the sample, and I _ex (λ) is the intensity of the excitation light before the sample is installed , I ′ _ex (λ) is the excitation light intensity observed when the sample is irradiated with the excitation light. By performing two spectrum observations of I _em and I ′ _ex + I _em , the emission quantum yield can be measured.

The measuring device is composed of an excitation light source, an excitation light guide unit, an integrating sphere, and a multichannel spectrometer. The excitation light output from the excitation light source is introduced into the integrating sphere via an excitation light guide unit including a condenser lens, an ND filter, and an optical fiber. Excitation light and sample emission are uniformly scattered within the integrating sphere and detected by a multi-channel spectrometer via an optical fiber probe. The measurement was performed under a nitrogen gas flow.

Excitation light source is HeCd laser Kinmon IK5352R-D (wavelength: 325 nm, output 10 mW), emission spectrum observation is a multi-channel spectrometer PMA-11 (C7473-36) made by Hamamatsu Photoelectronics, and integrating sphere is Labsphere IS- 080-SF was used.

A quartz substrate similar to the sample for measuring luminescence quantum yield was used as a blank substrate. The blank substrate was set in a substrate holder for measuring the emission quantum yield, and the excitation light spectrum I _ex (λ) was measured. The blank substrate was removed, a sample for measuring the emission quantum yield was set, and the excitation light spectrum and emission spectrum I ′ _ex (λ) + I _em (λ) were observed. The multichannel spectrometer was set to an exposure time of 200 ms and an averaging count of 20 times.

The quantum yield of the sample using the compound (1-1) was measured in the same manner as described above. The measurement results are shown in Table 2 below.

[Comparative Examples 1-3]
Samples using the compounds (2-1), (2-2) and CBP were measured in the same manner. The quantum yield (relative value) was calculated using the light emission quantum yield value of the sample using CBP as a standard value. The measurement results are shown in Table 2 below.

According to a preferred embodiment of the present invention, since it has a high Tg, a stable layer can be formed when used in a light emitting device. Further, the present invention provides an organic electroluminescence device having higher performance in at least one of heat resistance, light emission efficiency, current efficiency, device lifetime, external quantum efficiency, and the like, a display device including the same, and a lighting device including the same. be able to.

Claims (5)

Green phosphorescent host materials containing a compound represented by the following formula (1).

In the formula (1), Ar is aryl having 6 to 20 carbon atoms, and R ^{1 to} R ¹⁶ are all hydrogen. Comprising a compound represented by the following formula (1-1), green phosphorescent host materials of claim 1.

In the organic electroluminescent device having at least one organic compound layer sandwiched between a pair of electrodes consisting of an anode and a cathode, an organic electroluminescent contained in the emission layer of green phosphorescent host materials according to claim 1 or 2 element. Furthermore, the organic electroluminescent element of Claim 3 which contains an iridium complex, a platinum complex, or a rhenium complex in a light emitting layer. Furthermore, it has an electron transport layer and / or an electron injection layer disposed between the cathode and the light emitting layer, and at least one of the electron transport layer and the electron injection layer is a quinolinol-based metal complex, a pyridine derivative, and a phenanthroline derivative. The organic electroluminescent element according to claim 3 or 4, comprising at least one selected from the group consisting of: