WO2018179482A1 - Compound for organic electroluminescence element and organic electroluminescence element - Google Patents

Abstract

The purpose of the present invention is to provide an organic electroluminescence element which has a long life and emits blue light having high color purity. A dibenzo[c, g]fluorene compound including a specific substitution group of the present invention is contained in an organic electroluminescence element, whereby it becomes possible to provide an organic electroluminescence element which has a long life and emits blue light having high color purity.

Description

Compound for organic electroluminescence device and organic electroluminescence device

The present invention relates to a compound for organic electroluminescence device and an organic electroluminescence device.

An organic electroluminescent element is an electronic element in which a thin film containing a luminescent organic compound is sandwiched between an anode and a cathode. By injecting holes and electrons from each electrode, excitons of the light-emitting organic compound are generated, and the organic electroluminescent element emits light when the excitons return to the ground state.

As an element structure of an organic electroluminescent element, a two-layer type of a hole transport layer and an electron transport light-emitting layer, or a three-layer type of a hole transport layer, a light-emitting layer, and an electron transport layer has been studied. At present, in order to further enhance the recombination efficiency of injected holes and electrons, a structure in which a hole injection layer and an electron injection layer are inserted between an anode and a hole transport layer and a cathode and an electron transport layer, respectively, is the mainstream. It has become.

Organic electroluminescent elements are expected to be a technology for realizing light-emitting devices that are excellent in contrast, responsiveness, and viewing angle, low power consumption, thin and light, and are actively researched. In order to promote practical application to displays and the like, the light emitting efficiency and continuous drive life of the current elements are not sufficient in practical use, and further high-efficiency light emission and longer life are required. In addition, when considering application to full-color displays, it is necessary to emit blue, green, and red light with good color purity. However, these problems have not been sufficiently solved, especially for blue light emitting devices. There is a strong demand for improved properties of materials.

There are a wide variety of organic compounds as constituent materials for organic electroluminescent elements, and various organic materials have been proposed in order to solve the above problems. As a blue light emitting element material, for example, Patent Document 1 reports an example in which a benzofluorene having a diarylamino group and a dibenzofluorene derivative are used as a light emitting layer dopant. Patent Documents 2 and 3 report examples in which a dibenzo [c, g] fluorene derivative having an aryl group is used as a light emitting layer host material. Patent Document 4 reports a dibenzo [c, g] fluorene derivative substituted with a diarylamino group or an electron transporting substance.

Japanese Patent Laid-Open No. 2015-10077 JP 2009-274899 A JP 2010-132651 A International Publication No. 2003/051092

The present invention has been made in view of the above circumstances, and when used as a constituent material of an organic electroluminescence device, the compound for organic electroluminescence device and organic electroluminescence exhibiting long-life and high-purity blue light emission. An object is to provide an element.

In order to achieve the above object, the present invention contains a compound for an organic electroluminescence device represented by the following general formula (1) and the compound for an organic electroluminescence device alone or as a component of a mixture. An organic electroluminescent device is provided.

(In general formula (1),
Y ¹ and Y ² are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms.
X ¹ and X ² are each independently a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituent represented by any one of the following general formulas (2), (3), and (4). Yes, at least one of X ¹ and X ² is a substituent represented by any one of the following general formulas (2), (3), and (4). )

(In general formula (2),
Ar ¹ is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
m is an integer of 1 to 2. )

(In general formula (3),
Ar ² is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
n is an integer of 1 to 5. )

(In general formula (4),
Ar ³ is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
p is an integer of 1 to 2. )

According to such a compound for an organic electroluminescent element, when used as a constituent material of the organic electroluminescent element, it is possible to realize blue light emission having a long lifetime and high color purity. The reason why such an effect can be obtained by the compound for organic electroluminescence device of the present invention is not necessarily clear, but the present inventors consider as follows.

So far, triarylamine derivatives having various structures have been developed and reported as fluorescent emission dopants. A dopant having a triarylamino group generally exhibits high fluorescence intensity, has a high highest occupied orbital (HOMO), and efficiently generates hole traps and charge recombination on the dopant. An organic electroluminescent element can be realized. In such an organic electroluminescence device, it is generally considered that intensive charge recombination and subsequent dopant excitation and emission occur in the light emitting layer in the vicinity of the hole transport layer.

On the other hand, in Journal of Applied Physics, 107, 024507, (2010), the chemical reaction resulting from bond cleavage of the hole transport layer material that occurs near the interface between the light-emitting layer that is the charge recombination region and the hole transport layer is organic electroluminescence. It has been considered that it can contribute to a decrease in luminance associated with element driving.

That is, in an organic electroluminescent device using a triarylamine derivative as a dopant, the charge recombination region is likely to be concentrated near the interface between the light emitting layer and the hole transport layer. It is considered that there is a possibility that the decrease in

Therefore, the present inventors have a low minimum orbital (LUMO), and in an organic electroluminescent device using an electron-accepting light-emitting dopant, there is a high possibility of charge recombination in the vicinity of the interface between the light-emitting layer and the electron transport layer, We thought that the drive life could be improved because charge recombination near the interface between the light emitting layer and the hole transport layer could be suppressed.

In the compound for organic electroluminescence device represented by the general formula (1) according to the present invention, at least one aryl group having a cyano group, a fluoro group, or a trifluoromethyl group is dibenzo [c, g] fluorene. It has a structure substituted at the 9th and 9th positions. When the compound for organic electroluminescent elements of the present invention is used as a light emitting layer dopant, the lifetime of the organic electroluminescent element can be extended. The dibenzo [c, g] fluorene derivative of the present invention has a low LUMO and a property of easily trapping electrons as compared with a polycyclic aromatic compound generally used as a light emitting layer host material. It can be considered that charge recombination in the vicinity of the interface between the hole transport layer and the hole transport layer can be suppressed, and a decrease in luminance accompanying driving of the element can be suppressed.

On the other hand, when the electron acceptability of the luminescent dopant is very high, the driving lifetime is caused by the longer wavelength of the emission spectrum, that is, the color purity of blue light emission accompanying the decrease in LUMO, and the interaction with peripheral materials in the device. In other words, the organic electroluminescence element cannot be extended in life and color purity can be improved. The aryl group having a cyano group, a fluoro group, or a trifluoromethyl group imparts an appropriate electron accepting property to the dibenzo [c, g] fluorene of the present invention, and emits blue light having a high color purity around 430 nm to 470 nm and an organic electric field. The lifetime of the light emitting element can be extended.

In the organic electroluminescent element compound according to the present invention, X ¹ and X ² are each independently a substituent represented by any one of the general formulas (2), (3), and (4). Is preferred.

A compound for an organic electroluminescence device having such a structure has a suitable emission wavelength and electron acceptability that enable both high color purity and a long driving life as a blue light emitting dopant.

In the compound for an organic electroluminescent device according to the present invention, Ar ¹ , Ar ² , and Ar ³ are preferably a substituted or unsubstituted phenyl group, naphthyl group, or biphenyl group.

When Ar ¹ , Ar ² , and Ar ³ are the above substituents, it is possible to realize blue light emission with higher color purity. In addition, since the compound is easy to synthesize, it is possible to produce a compound for an organic electroluminescence device with few impurities, and thus it is possible to obtain an organic electroluminescence device with a long driving life.

In the organic electroluminescent element according to the present invention, it is preferable that the organic layer has a light emitting layer, and the light emitting layer contains the compound.

In the organic electroluminescent device according to the present invention, it is preferable that the light emitting layer has a host material and a dopant, and the dopant contains the compound.

According to such an organic electroluminescent device, since the dopant has an appropriate electron accepting property, the concentration of charge recombination at the interface between the light emitting layer and the hole transport layer and the interaction with the surrounding materials can be suppressed, and a long driving life can be achieved. It is possible to realize. Moreover, such an organic electroluminescent element emits blue light with high color purity.

Further, in the organic electroluminescent device according to the present invention, the organic layer has at least one of a hole injection layer or a hole transport layer, and at least a part of the hole injection layer or the hole transport layer functions as an electron acceptor, Or it is preferable that an organic compound is included.

In order to increase the efficiency of the organic electroluminescent device, it is necessary that the recombination of both the hole and electron carriers in the dopant occurs efficiently. For this purpose, the dopant sufficiently captures the carrier and counters the carrier. Is sufficiently supplied to the dopant in the light emitting layer. In addition, when both carriers do not recombine quickly, a compound in a radical state corresponding to excess carriers exists in the device, which inhibits light emission and causes a short life.

Since a compound that functions as an electron acceptor can generate holes by extracting electrons from an adjacent organic substance, in an organic electroluminescent device in which at least a part of a hole injection layer or a hole transport layer contains an electron acceptor, an anode The injection barrier from the injection of holes to the light emitting layer can be significantly reduced. As a result, since holes can be sufficiently supplied to the electron-accepting dopant used in the organic electroluminescence device of the present invention, light emission with high efficiency and long life is possible.

According to the present invention, it is possible to obtain an organic electroluminescent element that emits blue light with a long lifetime and high color purity.

It is a schematic cross section which shows an example of the organic electroluminescent element concerning this embodiment. 1 is a diagram showing a ¹ HNMR spectrum of a compound (11) of the present invention of Synthesis Example 1. FIG. It is a figure which shows the ¹³ CNMR spectrum of the compound (11) of this invention of the synthesis example 1. ¹ is a diagram showing a ¹ HNMR spectrum of a compound (12) of the present invention in Synthesis Example 2. FIG. It is a figure which shows the ¹³ CNMR spectrum of the compound (12) of this invention of the synthesis example 2. 4 is a diagram showing a ¹ HNMR spectrum of a compound (13) of the present invention in Synthesis Example 3. FIG. It is a figure which shows the ¹³ CNMR spectrum of the compound (13) of this invention of the synthesis example 3. It shows The ¹ HNMR spectrum of the compound of the present invention Synthesis Example 4 (14). It is a figure which shows the ¹³ CNMR spectrum of the compound (14) of this invention of the synthesis example 4. 6 is a diagram showing a ¹ HNMR spectrum of a compound (15) of the present invention in Synthesis Example 5. FIG. It is a figure which shows the ¹³ CNMR spectrum of the compound (15) of this invention of the synthesis example 5. 2 is a diagram showing a ¹ HNMR spectrum of a compound (16) of the present invention in Synthesis Example 6. FIG. It is a figure which shows the ¹³ CNMR spectrum of the compound (16) of this invention of the synthesis example 6. It shows The ¹ HNMR spectrum of the compound of the present invention synthesized in Synthesis Example 7 (17). It is a figure which shows the ¹³ CNMR spectrum of the compound (17) of this invention of the synthesis example 7. ¹ is a diagram showing a ¹ HNMR spectrum of a compound (18) of the present invention in Synthesis Example 8. FIG. It is a figure which shows the ¹³ CNMR spectrum of the compound (18) of this invention of the synthesis example 8.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

(Compound for organic electroluminescence device)
The compound for organic electroluminescent elements according to a preferred embodiment of the present invention is a dibenzo [c, g] fluorene compound having a specific structure represented by the following general formula (1).

(In general formula (1),
Y ¹ and Y ² are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms.
X ¹ and X ² are each independently a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituent represented by any one of the following general formulas (2), (3), and (4). Yes, at least one of X ¹ and X ² is a substituent represented by any one of the following general formulas (2), (3), and (4). )

(In general formula (2),
Ar ¹ is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
m is an integer of 1 to 2. )

(In general formula (3),
Ar ² is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
n is an integer of 1 to 5. )

(In general formula (4),
Ar ³ is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
p is an integer of 1 to 2. )

In the general formula (1), Y ¹ and Y ² are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, specifically, a methyl group, an ethyl group, a linear or branched group. Propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group.

In the general formula (1), Y ¹ and Y ² are each independently a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and specific examples thereof include a phenyl group, a naphthyl group, and a biphenyl group. It is done.

Y ¹ and Y ² are preferably a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, a naphthyl group, or a biphenylyl group from the viewpoint of the stability of the compound and the organic electroluminescent device and the ease of synthesis. Group, phenyl group, and biphenylyl group are more preferable. When Y ¹ and Y ² are each independently a phenyl group or a naphthyl group, Y ¹ and Y ² may be bonded to form a cyclic structure.

Y ¹ and Y ² may be the same or different.

The aryl group may be further substituted with a substituent. Examples of such a substituent include an aryl group, an alkyl group, an alkoxy group, an aryloxy group, a halogeno group, and a silyl group.

Among these substituents, an aryl group and an alkyl group are preferable from the viewpoint of the stability of the organic electroluminescent device, and a phenyl group, a naphthyl group, a biphenylyl group, a methyl group, an ethyl group, a propyl group, and a butyl group are more preferable.

In the general formula (1), X ¹ and X ² which are not a substituent represented by any one of the general formulas (2), (3) and (4) are substituted or unsubstituted 6 to 6 carbon atoms. 20 aryl groups, and specifically include phenyl, naphthyl, biphenylyl, fluorenyl, benzofluoryl, phenanthryl, anthracenyl, pyrenyl, chrysenyl, terphenylyl, tetracenyl and the like.

As the aryl group of X ¹ and X ² , a phenyl group, a naphthyl group, a biphenylyl group, a fluorenyl group, a benzofluoryl group, and a phenanthryl group are preferable, and a phenyl group, a naphthyl group, and a biphenylyl group are preferable because blue light emission with high color purity can be obtained. Groups are more preferred.

The aryl group may be further substituted with a substituent. Examples of such a substituent include an aryl group, an alkyl group, an alkoxy group, an aryloxy group, a halogeno group, and a silyl group.

Among these substituents, an aryl group and an alkyl group are preferred from the viewpoint of obtaining blue light emission with high stability and stability of the organic electroluminescent device, and phenyl group, naphthyl group, biphenylyl group, methyl group, ethyl group, A propyl group and a butyl group are more preferable.

In the general formula (1), at least one of X ¹ and X ² is represented by any one of the general formulas (2), (3), and (4).

In the general formula (1), X ¹ and X ² are preferably each independently a substituent represented by any of the general formulas (2), (3), and (4). The compound for an organic electroluminescence device having such a structure has a suitable emission wavelength and electron acceptability that enable both high color purity and a long drive life as a blue light emitting dopant.

In the general formula (1), at least one of X ¹ and X ² is preferably a substituent represented by the general formula (2). The compound for an organic electroluminescence device having such a structure exhibits high luminous efficiency in addition to high color purity and a long driving life as a blue light emitting dopant.

X ¹ and X ² may be the same or different.

In the general formulas (2), (3), and (4), Ar ¹ , Ar ² , and Ar ³ are each independently a substituted or unsubstituted aryl group having 6 to 16 carbon atoms, specifically, Examples thereof include a phenyl group, a naphthyl group, a biphenylyl group, a fluorenyl group, a phenanthryl group, an anthracenyl group, and a pyrenyl group.

Among these substituents, a phenyl group, a naphthyl group, a biphenylyl group, and a fluorenyl group are preferable, and a phenyl group, a naphthyl group, and a biphenylyl group are more preferable because blue light emission with high color purity can be obtained. Since such a structure is easy to synthesize, it is possible to produce a compound for an organic electroluminescence device with few impurities, and thus an organic electroluminescence device with a long driving life can be obtained.

The aryl group may be further substituted with a substituent. Examples of such a substituent include an aryl group, an alkyl group, an alkoxy group, an aryloxy group, a halogeno group, and a silyl group.

Among these substituents, an aryl group and an alkyl group are preferable from the viewpoint that the compound and the organic electroluminescence device can be stable and blue light emission with high color purity is obtained, and a phenyl group, a naphthyl group, a biphenylyl group, a methyl group, an ethyl group are preferable. A group, a propyl group, and a butyl group are more preferable.

In the general formula (2), m is an integer of 1 to 2, in the general formula (3), n is an integer of 1 to 5, and in the general formula (4), p is 1 to 2. It is an integer. According to such a structure, blue light emission with high color purity is possible.

The molecular weight of the compound according to the present embodiment is not particularly limited, but it is preferable that the molecular weight is 1300 or less in consideration of the element production process. This is because a compound having a molecular weight of 1300 or more is difficult to synthesize due to a decrease in solubility, and it is difficult to produce an organic electroluminescent device by a coating process. Further, even when an organic electroluminescent element is produced by a vapor deposition process, the vapor deposition temperature becomes high, which may cause decomposition of the material.

(Specific examples of compounds for organic electroluminescence devices)
Preferable examples of the compound for organic electroluminescence device represented by the general formula (1) according to this embodiment include the following formulas (I-1) to (I-36), (II-1) to (II- 31).

(Organic electroluminescence device)
FIG. 1 is a schematic cross-sectional view showing an example of an organic electroluminescent element according to this embodiment. The organic electroluminescent element 1 shown in FIG. 1 includes a hole injection layer 4, a hole transport layer 5, a light emitting layer 6, and two electrodes (first electrode 3 and second electrode 9) arranged to face each other. The electron transport layer 7 and the electron injection layer 8 are sandwiched. The hole injection layer 4, the hole transport layer 5, the light emitting layer 6, the electron transport layer 7, and the electron injection layer 8 are all organic layers, and are stacked in this order from the first electrode 3 side. The electron injection layer 8 may be an inorganic layer (metal layer, metal compound layer, etc.).

In the present embodiment, the first electrode 3 is formed on the substrate 2, but the stacking order from the substrate 2 side may be reversed. That is, even if the second electrode 9, the electron injection layer 8, the electron transport layer 7, the light emitting layer 6, the hole transport layer 5, the hole injection layer 4, and the first electrode 3 are stacked in this order from the substrate 2 side. Good.

Moreover, the organic electroluminescent element compound used in the present embodiment may be contained in any of the layers described above, but is preferably contained in the light emitting layer 6.

In the present embodiment, the first electrode 3 and the second electrode 9 function as a hole injecting electrode (anode) and an electron injecting electrode (cathode), respectively. As well as holes are injected from the second electrode 9, electrons are injected from the second electrode 9, and these recombination causes the organic electroluminescent element compound in the light emitting layer to emit light.

The preferred thicknesses of the hole injection layer 4, the hole transport layer 5, the light emitting layer 6, the electron transport layer 7 and the electron injection layer 8 are all 1 to 200 nm.

(substrate)
The substrate 2 can be used without particular limitation as long as it is provided in a conventional organic electroluminescence device, and is an amorphous substrate such as glass or quartz, Si, GaAs, ZnSe, ZnS, GaP. A crystal substrate such as InP or a metal substrate such as Mo, Al, Pt, Ir, Au, Pd, or SUS can be used. Further, a thin film made of a crystalline or amorphous ceramic, metal, organic substance or the like formed on a predetermined substrate may be used.

When the substrate 2 side is the light extraction side, it is preferable to use a transparent substrate such as glass or quartz as the substrate 2, and it is particularly preferable to use an inexpensive glass transparent substrate. The transparent substrate may be provided with a color filter film, a color conversion film containing a fluorescent material, a dielectric reflection film, or the like for adjusting the emission color.

(First electrode)
The first electrode 3 functions as a hole injection electrode (anode). Therefore, the material of the first electrode 3 can be used without particular limitation as long as it is provided in the conventional organic electroluminescent element, but it can be used efficiently and uniformly for the first electrode 3. A material capable of applying an electric field to is preferable.

Further, when the substrate 2 side is the light extraction side, the transmittance at a wavelength of 400 nm to 700 nm, which is the emission wavelength region of the organic electroluminescence element, in particular, the transmittance of the first electrode 3 at the wavelength of each RGB color is 50%. Preferably, it is 80% or more, more preferably 90% or more. When the transmittance of the first electrode 3 is less than 50%, the light emission from the light emitting layer 6 is attenuated, and the luminance necessary for image display cannot be obtained.

The 1st electrode 3 with high light transmittance can be comprised using the transparent conductive film comprised with various oxides. As such a material, indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), and the like are preferable. It is particularly preferable in that a thin film having a uniform in-plane specific resistance can be easily obtained.

The film thickness of the first electrode 3 is preferably determined in consideration of the light transmittance described above. For example, when an oxide transparent electrode is used, the film thickness is preferably 10 to 500 nm, more preferably 30 to 300 nm. When the film thickness of the first electrode 3 exceeds 500 nm, the light transmittance becomes insufficient and the first electrode 3 may be peeled off from the substrate 2 in some cases. In addition, the light transmittance is improved as the film thickness is decreased. However, when the film thickness is less than 10 nm, the resistance increases and the driving voltage of the organic electroluminescent element tends to increase.

(Second electrode)
The second electrode 9 functions as an electron injection electrode (cathode). The material of the second electrode 9 can be used without particular limitation as long as it is provided in a conventional organic electroluminescent device, and examples thereof include metal materials, organometallic complexes, and metal compounds. In order to efficiently and reliably inject electrons into the light emitting layer 6, it is preferable to use a material having a relatively low work function, and it may be transparent.

Specific examples of the metal material constituting the second electrode 9 include alkali metals such as Li, Na, K or Cs, alkaline earth metals such as Mg, Ca, Sr or Ba, or Al (aluminum). . Alternatively, a metal having properties similar to those of an alkali metal or alkaline earth metal such as La, Ce, Sn, Zn, or Zr can be used. Furthermore, oxides or halides of the above metal materials can also be used. Further, it may be a mixture or alloy containing the above materials, and a plurality of these may be laminated.

The film thickness of the second electrode 9 only needs to be such that electrons can be uniformly injected, and may be 0.1 nm or more.

An auxiliary electrode may be provided on the second electrode 9. Thereby, the electron injection efficiency to the light emitting layer 6 can be improved, and the penetration | invasion of the water | moisture content or the organic solvent to the electron injection layer 8, the electron carrying layer 7, and the light emitting layer 6 can be prevented. As a material for the auxiliary electrode, a general metal can be used because there is no restriction on work function and charge injection capability. However, it is preferable to use a metal having high conductivity and easy handling. In particular, when the second electrode 9 includes an organic material, it is preferable to select appropriately according to the type and adhesion of the organic material.

Examples of the material used for the auxiliary electrode include Al, Ag, In, Ti, Cu, Au, Mo, W, Pt, Pd, and Ni. Among them, by using a low-resistance metal such as Al and Ag. Electron injection efficiency can be further increased. Further, by using a metal compound such as TiN, higher sealing performance can be realized. These materials may be used alone or in combination of two or more. Moreover, when using 2 or more types of metals, you may use as an alloy. Such an auxiliary electrode can be formed by, for example, a vacuum deposition method or the like.

(Hole injection layer)
The hole injection layer 4 is a layer containing a compound having a function of facilitating hole injection from the first electrode 3. Specifically, it can be formed using at least one kind of hydrocarbon-based material such as triarylamine derivative, carbazole derivative, anthracene derivative, azatriphenylene derivative, phthalocyanine derivative, polyaniline / organic acid, polythiophene / polymer acid, and the like. it can.

(Hall transport layer)
The hole transport layer 5 is a layer containing a compound having a function of transporting injected holes to the light emitting layer 6 and a function of preventing electrons in the light emitting layer 6 from being injected into the hole transport layer 5. The hole transport layer 5 uses at least one kind of hydrocarbon compound such as triarylamine derivative, triarylmethane derivative, stilbene derivative, polysilane derivative, polyphenylene vinylene and derivative thereof, polythiophene and derivative thereof, carbazole derivative, or anthracene derivative. Can be formed.

In addition, if it is a material which has the function of the hole injection layer 4 and the hole transport layer 5 as a hole injection transport layer, it is possible to fulfill the function of two layers by a single layer. On the other hand, the hole injection layer 4 and the hole transport layer 5 can be further functionally separated into a plurality of layers.

When a material having a high work function such as a carbazole derivative or a hydrocarbon-based material is used for the hole injection layer 4 or the hole transport layer 5, hole injection from the anode 3 to the hole injection layer 4 or from the hole injection layer 4 to the hole transport layer 5 is performed. Although the barrier is increased, holes can be forcibly generated by containing an inorganic compound or an organic material functioning as an electron acceptor in a part of the hole injection layer 4 or the hole transport layer 5. The injection barrier can be lowered.

As such an inorganic compound, antimony chloride, vanadium oxide, ruthenium oxide, tungsten oxide, zinc oxide, tin oxide, iron oxide, molybdenum oxide and the like can be used, and molybdenum oxide is particularly preferable. As such an organic material, hexacyanoazatriphenylene or a derivative thereof can be used.

(Light emitting layer)
The light emitting layer 6 is a layer containing a compound having a function of transporting injected holes and electrons and a function of generating excitons by recombination of holes and electrons. The compound represented by the general formula (1) according to the present embodiment is preferably included in the light emitting layer 6, and more preferably included in the light emitting dopant. An organic electroluminescent element provided with the light emitting layer 6 containing such a material exhibits blue light emission with a long lifetime and high color purity as compared with a conventional organic electroluminescent element.

When the compound of the general formula (1) is contained in the luminescent dopant, the content with respect to the host material is preferably 0.01 to 20 wt%, and more preferably 0.1 to 15 wt%.

Examples of the host material that forms the light emitting layer 6 together with the light emitting dopant containing the compound of the general formula (1) include organic metal complexes such as tris (8-quinolinolato) aluminum, carbonization such as naphthalene, anthracene, naphthacene, pyrene, and perylene. In addition to hydrogen compound derivatives, heterocyclic derivatives such as carbazole, thiophene, and furan, and triarylamine derivatives can be used. In this embodiment, it is preferable to use anthracene derivatives and pyrene derivatives as host materials.

In the present embodiment, preferable examples of the anthracene derivative and the pyrene derivative used as the light emitting layer host material include compounds represented by the following formulas (III-1) to (III-32).

The light emitting layer 6 may contain other compounds such as a host material and a dopant. By mixing other compounds, carrier transport can be adjusted, and by mixing fluorescent dyes, the emission color can be converted and used. Examples of the compound that regulates carrier transport include metal complex compounds having 8-quinolinol or a derivative thereof such as tris (8-quinolinolato) aluminum as a ligand, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, imidazopyridine derivatives, Electron transporting compounds such as imidazopyrimidine derivatives and phenanthroline derivatives, hole transporting compounds such as triarylamine derivatives, and the like can be preferably used.

(Electron transport layer)
The electron transport layer 7 has a function of transporting injected electrons and a function of preventing holes from being injected into the electron transport layer 7 from the light emitting layer 6. The electron transport layer 7 includes, for example, organometallic complexes having an 8-quinolinol or a derivative thereof such as tris (8-quinolinolato) aluminum as a ligand, oxadiazole derivatives, triazole derivatives, triazine derivatives, perylene derivatives, quinoline derivatives, Quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorenone derivatives, thiopyrandioxide derivatives, pyridine derivatives, pyrimidine derivatives, imidazopyridine derivatives, imidazopyrimidine derivatives, heterocyclic compounds such as phenanthroline derivatives, anthracene, pyrene, naphthacene, fluoranthene, acenaphtho It can be formed using at least one hydrocarbon derivative such as fluoranthene.

(Electron injection layer)
The electron injection layer 8 has a function of facilitating injection of electrons from the second electrode 9 and a function of improving adhesion with the second electrode 9. The electron injection layer 8 is composed of a metal complex, an oxadiazole derivative, a triazole derivative, a triazine derivative, a quinoline derivative, a quinoxaline derivative, a pyridine derivative having an 8-quinolinol or its derivative such as tris (8-quinolinolato) aluminum as a ligand. , Pyrimidine derivatives, imidazole derivatives, imidazopyrimidine derivatives, phenanthroline derivatives and the like can be used.

The organic electroluminescence device according to this embodiment can be produced by a known method except that the compound for organic electroluminescence device according to this embodiment is contained. As a method for forming each organic layer, a vacuum vapor deposition method, an ionization vapor deposition method, a coating method, or the like can be appropriately selected and employed depending on the material constituting the organic layer.

Specific examples of the coating method include a spin coating method, various printing methods such as gravure printing, and an ink jet method. Examples of the solvent used in this coating method include hydrocarbon solvents such as toluene and xylene, and halogen solvents such as dichloroethane. The compound represented by the general formula (1) according to the present embodiment has high solubility and can be sufficiently formed by a coating process. In the case of spin coating, a thin film with a thickness of about 50 nm to 200 nm can be formed by using a solution having a concentration of about 1 to 3%.

The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the following Example.
<Synthesis Example 1>
The following compound (11) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of [1,1′-Binaphthalene] -2-carboxylate methyl (1-1))
Under an argon stream, 13.26 g (50.0 mmol) of 1-bromo- (2-naphthalenecarboxylate), 10.32 g (60.0 mmol) of 1-naphthaleneboronic acid, tris (dibenzylideneacetone) dipalladium (0) Dissolve 0.229 g (0.25 mmol), 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl 0.205 g (0.50 mmol), and potassium phosphate tribasic acid 31.84 g (150.0 mmol) in 200 ml of toluene. And stirred for 65 hours under reflux. After cooling to room temperature, water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The resulting crude product was purified by column chromatography to obtain the desired [1,1′-binaphthalene] -2-carboxylate methyl ester (1-1) as a white solid (yield 14.92 g, yield 96%). Obtained.

(Synthesis of α, α-dimethyl-([1,1′-binaphthalene] -2-methanol) (1-2))
Under a stream of argon, 14.92 g of methyl [1,1′-binaphthalene] -2-carboxylate (1-1) synthesized by the above reaction was added to 1400 ml of dehydrated diethyl ether solution containing 143.4 mmol of methyl magnesium iodide. 8 ml) was added dropwise over 30 minutes, and the mixture was stirred at room temperature for 15 hours. A saturated aqueous ammonium chloride solution was added to the reaction solution, and the mixture was extracted with diethyl ether. The organic layer was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by column chromatography, and the desired α, α-dimethyl-([1,1′-binaphthalene] -2-methanol) (1-2) white solid (yield 13.08 g, Yield 88%).

(Synthesis of 7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-3))
In an argon stream, 13.08 g (41.9 mmol) of α, α-dimethyl-([1,1′-binaphthalene] -2-methanol) (1-2) synthesized by the above reaction was dissolved in 150 ml of dehydrated dichloromethane. Cooled in an ice bath. 7.8 ml (62.9 mmol) of boron trifluoride diethyl ether complex was added dropwise over 10 minutes, and then stirred at room temperature for 21 hours. Water was added to the reaction solution and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography, and the desired 7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-3) white solid (yield 11.92 g, yield 97). %).

(Synthesis of 5,9-dibromo-7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-4))
In an argon stream, 11.92 g (40.5 mmol) of 7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-3) synthesized by the above reaction was dissolved in 120 ml of dehydrated dichloromethane, It was cooled with. N-bromosuccinimide (15.86 g, 89.1 mmol) was slowly added, and then the mixture was stirred at room temperature for 18 hours. Water was added to the reaction solution and extracted with dichloromethane. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain the desired 5,9-dibromo-7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-4) white solid (yield 16 .35 g, 89% yield).

(Synthesis of 5-bromo-7,7-dimethyl-9- (4-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (1-5))
5,9-dibromo-7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-4) (76) synthesized by the above reaction under an argon stream, 4-cyano 0.598 g (4.07 mmol) of phenylboronic acid and 0.277 g (0.24 mmol) of tetrakis (triphenylphosphine) palladium (0) were dissolved in 25 ml of toluene and 3 ml of ethanol. Next, 6.1 ml of an aqueous solution containing 12.2 mmol of sodium carbonate was added, and the mixture was stirred for 40 hours under reflux with heating. After cooling to room temperature, water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from hexane to obtain the desired 5-bromo-7,7-dimethyl-9- (4-cyanophenyl)-(7H-dibenzo [c, g]. A white solid (fluorine) (1-5) (yield 0.970 g, yield 50%) was obtained.

(Synthesis of 5- (3,4-dicyanophenyl) -7,7-dimethyl-9- (4-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (11))
0.854 g (1) of 5-bromo-7,7-dimethyl-9- (4-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (1-5) synthesized by the above reaction under an argon stream .80 mmol), 4- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -1,2-benzenedicarbonitrile 0.522 g (2.05 mmol), palladium acetate (0) 0.012 g (0.054 mmol), 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl 0.044 g (0.108 mmol), potassium phosphate tribasic acid 0.764 g (3.60 mmol) The resultant was dissolved in 10 ml of toluene and 0.5 ml of water, and stirred for 17 hours under heating and reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 5- (3,4-dicyanophenyl) -7,7-dimethyl-9- (4-cyanophenyl)- A white powder (yield 0.734 g, yield 78%) of (7H-dibenzo [c, g] fluorene) (11) was obtained. Furthermore, sublimation purification was performed to obtain a product having a purity of 99.8% (confirmed by high performance liquid chromatography (HPLC)).

As a result of mass spectrometry of the obtained compound, a peak was confirmed at m / z = 521 (M ⁻ ). Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 2 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹³ C-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 3 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 1 was the compound (11).

<Synthesis Example 2>
The following compound (12) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of 5- (3,5-dicyanophenyl) -7,7-dimethyl-9- (4-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (12))
0.970 g (2) of 5-bromo-7,7-dimethyl-9- (4-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (1-5) synthesized by the above reaction under an argon stream .04 mmol), 4- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -1,3-benzenedicarbonitrile 0.623 g (2.45 mmol), palladium acetate (0) 0.023 g (0.10 mmol), 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl 0.082 g (0.20 mmol), potassium phosphate tribasic acid 1.299 g (6.12 mmol) The product was dissolved in 10 ml of toluene and 0.5 ml of water, and stirred for 23 hours under heating and reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 5- (3,5-dicyanophenyl) -7,7-dimethyl-9- (4-cyanophenyl)- A white powder (yield 0.751 g, yield 71%) of (7H-dibenzo [c, g] fluorene) (12) was obtained. Furthermore, sublimation purification was performed to obtain a product having a purity of 99.1% (confirmed by high performance liquid chromatography (HPLC)).

As a result of mass spectrometry of the obtained compound, a peak was confirmed at m / z = 521 (M ⁻ ). Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 4 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹³ C-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 5 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 2 was the compound (12).
(12) was confirmed.

<Synthesis Example 3>
The following compound (13) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of 5-bromo-7,7-dimethyl-9- (3-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (1-6))
5,9-Dibromo-7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-4) 4.527 g (10.0 mmol), 3-cyano synthesized by the above reaction under an argon stream 1.029 g (7.00 mmol) of phenylboronic acid and 0.485 g (0.42 mmol) of tetrakis (triphenylphosphine) palladium (0) were dissolved in 40 ml of toluene and 5 ml of ethanol. Next, 10.5 ml of an aqueous solution containing 21.0 mmol of sodium carbonate was added, and the mixture was stirred for 18 hours under reflux with heating. After cooling to room temperature, water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain the desired 5-bromo-7,7-dimethyl-9- (3-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (1-6 ) White solid (yield 2.111 g, yield 45%).

(Synthesis of 5- (3,4-dicyanophenyl) -7,7-dimethyl-9- (3-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (13))
1.423 g (3) of 5-bromo-7,7-dimethyl-9- (3-cyanophenyl)-(7H-dibenzo [c, g] fluorene) (1-6) synthesized by the above reaction under an argon stream .00 mmol), 4- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -1,2-benzenedicarbonitrile 0.915 g (3.60 mmol), palladium acetate (0) 0.034 g (0.15 mmol), 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl 0.123 g (0.30 mmol), potassium phosphate tribasic acid 1.274 g (6.00 mmol) The resultant was dissolved in 15 ml of toluene and 0.6 ml of water, and stirred for 18 hours while heating under reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The resulting crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 5- (3,4-dicyanophenyl) -7,7-dimethyl-9- (3-cyanophenyl)- A white powder (yield 1.156 g, yield 74%) of (7H-dibenzo [c, g] fluorene) (13) was obtained. Furthermore, sublimation purification was performed to obtain a product having a purity of 99.9% (purity confirmed by high performance liquid chromatography (HPLC)).

As a result of mass spectrometry of the obtained compound, a peak was confirmed at m / z = 521 (M ⁻ ). Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 6 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹³ C-NMR) When analyzed using the method, the ¹³ C-NMR spectrum shown in FIG. 7 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 3 was the compound (13).

<Synthesis Example 4>
The following compound (14) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of 5-bromo-7,7-dimethyl-9- [4- (trifluoromethyl) phenyl]-(7H-dibenzo [c, g] fluorene) (1-7))
5,9-Dibromo-7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-4) synthesized by the above reaction under an argon stream, 4-939 g (6.50 mmol), 4- ( 0.950 g (5.00 mmol) of trifluoromethyl) phenylboronic acid and 0.289 g (0.25 mmol) of tetrakis (triphenylphosphine) palladium (0) were dissolved in 30 ml of toluene and 4 ml of ethanol. Next, 7.50 ml of an aqueous solution containing 15.0 mmol of sodium carbonate was added, and the mixture was stirred for 23 hours while heating under reflux. After cooling to room temperature, water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain the desired 5-bromo-7,7-dimethyl-9- [4- (trifluoromethyl) phenyl]-(7H-dibenzo [c, g] fluorene). A white solid of (1-7) (yield 1.670 g, yield 65%) was obtained.

(5- [3,5-bis (trifluoromethyl) phenyl] -7,7-dimethyl-9-([4- (trifluoromethyl) phenyl]-(7H-dibenzo [c, g] fluorene) (14 )
5-Bromo-7,7-dimethyl-9- [4- (trifluoromethyl) phenyl]-(7H-dibenzo [c, g] fluorene) (1-7) 1 synthesized by the above reaction under an argon stream 670 g (3.23 mmol), 3,5-bis (trifluoromethyl) phenylboronic acid 0.998 g (3.87 mmol), tris (dibenzylideneacetone) dipalladium (0) 0.147 g (0.16 mmol), 2-Dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl (0.131 g, 0.32 mmol) and potassium phosphate tribasic acid (2.064 g, 9.69 mmol) were dissolved in toluene (30 ml) and heated under reflux for 21 hours. Stir. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 5- [3,5-bis (trifluoromethyl) phenyl] -7,7-dimethyl-9-([[ A white powder (yield 1.622 g, yield 77%) of 4- (trifluoromethyl) phenyl]-(7H-dibenzo [c, g] fluorene) (14) was obtained. A 99.9% product (purity confirmed by high performance liquid chromatography (HPLC)) was obtained.

As a result of mass spectrometry of the obtained compound, a peak was confirmed at m / z = 650 (M ⁻ ). Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 8 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹³ C-NMR) When analyzed using the method, the ¹³ C-NMR spectrum shown in FIG. 9 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 4 was the compound (14).

<Synthesis Example 5>
The following compound (15) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of 5- (3,4-dicyanophenyl) -7,7-dimethyl-9- [4- (trifluoromethyl) phenyl]-(7H-dibenzo [c, g] fluorene) (15))
5-Bromo-7,7-dimethyl-9- [4- (trifluoromethyl) phenyl]-(7H-dibenzo [c, g] fluorene) (1-7) 1 synthesized by the above reaction under an argon stream 142 g (2.21 mmol), 4- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -1,2-benzenedicarbonitrile 0.618 g (2.43 mmol) ), Palladium acetate (0) 0.025 g (0.11 mmol), 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl 0.090 g (0.22 mmol), potassium phosphate tribasic acid 0.938 g (4 .42 mmol) was dissolved in 15 ml of toluene and 0.4 ml of water, and the mixture was stirred for 18 hours with heating under reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 5- (3,4-dicyanophenyl) -7,7-dimethyl-9- [4- (trifluoromethyl). ) Phenyl]-(7H-dibenzo [c, g] fluorene) (15) was obtained as a white powder (1.031 g, 83% yield). Furthermore, sublimation purification was performed to obtain a product having a purity of 99.9% (purity confirmed by high performance liquid chromatography (HPLC)).

As a result of mass spectrometry of the obtained compound, a peak was confirmed at m / z = 564 (M ⁻ ). Also, Analysis of this compound ¹ H- using nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 10 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹³ C-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 11 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 5 was the compound (15).

<Synthesis Example 6>
The following compound (16) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of 5,9-bis [4- (trifluoromethyl) phenyl] -7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (16))
5,9-Dibromo-7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-4) 1.000 g (2.21 mmol), 4- ( (Trifluoromethyl) phenylboronic acid 0.925 g (4.87 mmol), tris (dibenzylideneacetone) dipalladium (0) 0.119 g (0.13 mmol), 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl 0.107 g (0.26 mmol) and 2.825 g (13.3 mmol) of potassium phosphate tribasic acid were dissolved in 30 ml of toluene, and the mixture was stirred for 18 hours with heating under reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 5,9-bis [4- (trifluoromethyl) phenyl] -7,7-dimethyl- (7H-dibenzo A white powder (yield: 1.030 g, yield: 80%) of [c, g] fluorene) (16) was obtained. Furthermore, sublimation purification was performed to obtain a product having a purity of 99.9% (purity confirmed by high performance liquid chromatography (HPLC)).

As a result of mass spectrometry of the obtained compound, a peak was confirmed at m / z = 582 (M ⁻ ). Also, Analysis of this compound ¹ H- using nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 12 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹³ C-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 13 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 6 was the compound (16).

<Synthesis Example 7>
The following compound (17) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of 5,9-bis (3,5-difluorophenyl) -7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (17))
5,9-Dibromo-7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-4) 1.000 g (2.21 mmol), 3,5 synthesized by the above reaction under an argon stream -0.768 g (4.87 mmol) of difluorophenylboronic acid, 0.119 g (0.13 mmol) of tris (dibenzylideneacetone) dipalladium (0), 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl 107 g (0.26 mmol) and 2.825 g (13.3 mmol) of potassium phosphate tribasic acid were dissolved in 30 ml of toluene, and the mixture was stirred for 18 hours with heating under reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The resulting crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 5,9-bis (3,5-difluorophenyl) -7,7-dimethyl- (7H-dibenzo [c , G] fluorene) (17) was obtained as a white powder (yield 0.623 g, yield 54%). Furthermore, sublimation purification was performed to obtain a 99.6% pure product (purity confirmed by high performance liquid chromatography (HPLC)).

As a result of mass spectrometry of the obtained compound, a peak was confirmed at m / z = 518 (M ⁻ ). Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 14 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹³ C-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 15 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 7 was the compound (17).

<Synthesis Example 8>
The following compound (18) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of 5,9-bis (6-cyanonaphthalen-2-yl) -7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (18))
5,9-Dibromo-7,7-dimethyl- (7H-dibenzo [c, g] fluorene) (1-4) 1.000 g (2.21 mmol), 6- (synthesized by the above reaction under an argon stream 4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -2-naphthalenecarbonitrile 1.358 g (4.87 mmol), palladium acetate (0) 0.040 g (0.18 mmol) ), 0.148 g (0.36 mmol) of 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl and 2.815 g (13.3 mmol) of potassium phosphate tribasic acid were dissolved in 30 ml of toluene and 1 ml of water and heated. Stir for 20 hours under reflux. After cooling to room temperature, the mixture was concentrated under reduced pressure, water was added, and the mixture was extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 5,9-bis (6-cyanonaphthalen-2-yl) -7,7-dimethyl- (7H-dibenzo A white powder of [c, g] fluorene) (18) was obtained (yield 1.292 g, yield 98%). Furthermore, sublimation purification was performed to obtain a product having a purity of 99.9% (purity confirmed by high performance liquid chromatography (HPLC)).

As a result of mass spectrometry of the obtained compound, a peak was confirmed at m / z = 596 (M ⁻ ). Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 16 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹³ C-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 17 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 8 was the compound (18).

The fluorescence spectra of the compounds (11) to (18) obtained in Synthesis Examples 1 to 8 were measured. Table 1 shows the maximum emission wavelength in the toluene solution. Any compound has a maximum fluorescence wavelength in the vicinity of 430 nm to 470 nm and is suitable as a blue light-emitting dopant with high color purity.

<Example 1>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. The surface of the transparent electrode was washed with UV / O ₃ and then fixed to a substrate holder of a vacuum evaporation apparatus, and the inside of the layer was decompressed to 1 × 10 ⁻⁴ Pa or less.

Next, while maintaining the reduced pressure state, dipyrazino [2,3-f: 2 ′, 3′-h] quinoxaline-2,3,6,7,10,11-hexacarbonitrile (21) having the following structure was obtained. Vapor deposition was performed at a deposition rate of 0.1 nm / sec to a thickness of 5 nm to form a hole injection layer.

Next, while maintaining the reduced pressure state, N, N, N ′, N′-tetrakis (3-biphenylyl) -1,1′-biphenyl-4,4′-diamine (22) having the following structure was deposited at a deposition rate. Vapor deposition was performed at a thickness of 80 nm at 0.1 nm / sec to form a hole transport layer.

Further, while maintaining the reduced pressure state, the compound (III-2) of the present embodiment as a host material and the compound (11) of the present embodiment as a dopant at a mass ratio of 95: 5 and an overall deposition rate of 0. A light emitting layer was formed by vapor deposition to a thickness of 40 nm at 1 nm / sec.

Further, while maintaining the reduced pressure state, the compound (III-2) of the present embodiment was deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec to form an electron transport layer.

Further, while maintaining the reduced pressure state, 9,10-bis [4- (imidazo [1,2-a] pyridin-2-yl) phenyl] anthracene (23) having the following structure was deposited at a deposition rate of 0.1 nm / The film was successively deposited to a thickness of 10 nm in sec to form an electron injection layer.

Next, LiF was deposited at a deposition rate of 0.1 nm / sec to a thickness of 1.2 nm, used as an electron injection electrode, Al as a protective electrode was deposited to a thickness of 100 nm, and finally sealed with glass to produce organic electroluminescence. An element was obtained.

The organic electroluminescent device fabricated, during driving at a current density of 10 mA / cm ^2, half life at an initial luminance of 1000 cd / ^{m 2,} the chromaticity (CIEx, CIE y), and the luminous efficiency was measured. The results are shown in Table 2.

<Examples 2 to 15 and Comparative Examples 1 to 6>
An organic electroluminescent device was produced in the same manner as in Example 1 except that the compounds listed in Table 2 were used in place of the compounds (III-2) and (11). Table 2 shows the half-life, chromaticity (CIEx, CIEy), and luminous efficiency at an initial luminance of 1000 cd / m ² when these elements are driven at a current density of 10 mA / cm ² . In addition, the compound used for a comparative example has the structure shown below.

According to Examples 1 to 15 and Comparative Examples 1 to 6, the organic electroluminescent device using the compound used in the present embodiment as a dopant was compared with the device using Comparative compounds (31) to (35) as the dopant. It was shown that the half life was long and the blue color purity was high. In addition, the dopant used in the present embodiment showed higher luminous efficiency when the light emitting layer was formed using an anthracene or pyrene compound having a dibenzo [a, c] fluorene structure as a host material.

<Example 16>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. The surface of the transparent electrode was washed with UV / O ₃ and then fixed to a substrate holder of a vacuum evaporation apparatus, and the inside of the layer was decompressed to 1 × 10 ⁻⁴ Pa or less.

Next, while maintaining the reduced pressure state, the compound (III-2) of the present embodiment and molybdenum oxide as an electron acceptor were formed in a volume ratio of 95: 5 and the film thickness was 50 nm at an overall deposition rate of 0.1 nm / sec. Evaporation was performed to form a hole injection layer.

Next, while maintaining the reduced pressure state, the compound (III-2) of the present embodiment was deposited to a thickness of 50 nm at a deposition rate of 0.1 nm / sec to form a hole transport layer.

Further, while maintaining the reduced pressure state, the compound (III-2) of the present embodiment as a host material and the compound (11) of the present embodiment as a dopant at a volume ratio of 95: 5 and an overall deposition rate of 0.1 nm / The film was deposited in a thickness of 40 nm in sec to obtain a light emitting layer.

Further, while maintaining the reduced pressure state, the compound (III-2) of the present embodiment was deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec to form an electron transport layer.

Further, while maintaining the reduced pressure state, the compound (23) was successively deposited to a thickness of 10 nm at a deposition rate of 0.1 nm / sec to obtain an electron injection layer.

Next, LiF was deposited at a deposition rate of 0.1 nm / sec to a thickness of 1.2 nm, used as an electron injection electrode, Al as a protective electrode was deposited to a thickness of 100 nm, and finally sealed with glass to produce organic electroluminescence. An element was obtained.

The organic electroluminescent device fabricated, during driving at a current density of 10 mA / cm ^2, half life at an initial luminance of 1000 cd / ^{m 2,} the chromaticity (CIEx, CIE y), and the luminous efficiency was measured. The results are shown in Table 3.

<Examples 17 to 27, Comparative Examples 7 to 12>
An organic electroluminescent device was produced in the same manner as in Example 16 except that the compounds listed in Table 3 were used instead of the compounds (III-2) and (11). Table 3 shows the half-life, chromaticity (CIEx, CIEy), and luminous efficiency at an initial luminance of 1000 cd / m ² when these elements are driven at a current density of 10 mA / cm ² .

According to Examples 16 to 27 and Comparative Examples 7 to 12, the organic electroluminescent devices using the compounds used in Examples 16 to 27 as dopants were compared with the devices using Comparative compounds (31) to (35) as dopants. It was shown that the luminance half-life was long and the blue color purity was high. In addition, the dopant used in the present embodiment showed higher luminous efficiency when the light emitting layer was formed using an anthracene or pyrene compound having a dibenzo [a, c] fluorene structure as a host material.

As described in detail above, the organic electroluminescent device containing the organic electroluminescent device compound of the present invention in the organic thin film layer can realize long-life blue light emission with high color purity.

DESCRIPTION OF SYMBOLS 1 ... Organic electroluminescent element concerning this embodiment, 2 ... Substrate, 3 ... 1st electrode, 4 ... Hole injection layer, 5 ... Hole transport layer, 6 ... Light emitting layer, 7 ... Electron transport layer, 8 ... Electron injection Layer, 9 ... second electrode, P ... power source.

Claims (7)

1. The compound for organic electroluminescent elements characterized by being represented by the following general formula (1).
   

   

   (In general formula (1),
   Y ¹ and Y ² are each independently a linear or branched alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms.
   X ¹ and X ² are each independently a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituent represented by any one of the following general formulas (2), (3), and (4). Yes, at least one of X ¹ and X ² is a substituent represented by any one of the following general formulas (2), (3), and (4). )
   

   

   (In general formula (2),
   Ar ¹ is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
   m is an integer of 1 to 2. )
   

   

   (In general formula (3),
   Ar ² is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
   n is an integer of 1 to 5. )
   

   

   (In general formula (4),
   Ar ³ is a substituted or unsubstituted aryl group having 6 to 16 carbon atoms.
   p is an integer of 1 to 2. )
2. The compound for organic electroluminescent elements according to claim 1, wherein X ¹ and X ² are each independently a substituent represented by any one of General Formulas (2), (3), and (4).
3. Ar ¹ , Ar ² , Ar ³ is a substituted or unsubstituted phenylene group, naphthylene group, or biphenylene group, The compound for organic electroluminescent elements according to claim 1 or 2.
4. 4. The organic electroluminescence device in which one or more organic layers are sandwiched between a pair of electrodes composed of an anode and a cathode, wherein at least one of the organic layers is according to claim 1. An organic electroluminescent device comprising a compound for an organic electroluminescent device alone or as a component of a mixture.
5. The organic electroluminescent element according to claim 4, wherein the organic layer has a light emitting layer, and the light emitting layer contains the compound.
6. 6. The organic electroluminescent device according to claim 5, wherein the light emitting layer has a host material and a dopant, and the dopant contains the compound.
7. The organic layer has at least one of a hole injection layer and a hole transport layer, and at least a part of the hole injection layer or the hole transport layer contains an inorganic compound or an organic compound that functions as an electron acceptor. Item 7. The organic electroluminescence device according to any one of Items 4 to 6.

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