JPH0798787B2 - Styryl compound, method for producing the same, and electroluminescence device comprising the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel styryl compound, a method for producing the same, and an electroluminescent device comprising the same. More specifically, the present invention relates to a novel styryl compound useful as a light emitting material for an electroluminescent device (EL device) and its efficiency. The present invention relates to a good manufacturing method and an EL device using the styryl compound.

[0002]

2. Description of the Related Art Focusing on the high fluorescence efficiency of organic compounds, research on devices utilizing the EL performance of organic compounds has been conducted for a long time. For example,
W. Helfrish, Dresmer, Williams et al. Obtained blue emission using anthracene crystal (J. Chem. Phys., 44 , 2902).
(1966)). In addition, Vincett and Barlow et al. Manufacture a light emitting device by a vacuum evaporation method of a condensed polycyclic aromatic compound (Thin Solid Films, 99 , 171 (1982)). However, in all cases, only those with low emission brightness and emission efficiency have been obtained.
Recently, using tetraphenyl butadiene as a light emitting material 1
It has been reported that blue emission of 00 cd / m ² was obtained (Japanese Patent Laid-Open No. 194393/1984). Furthermore, by stacking a hole-conductive diamine compound and a fluorescent aluminum chelate complex as a light emitting material, a brightness of 1000 is obtained.
It has been reported that a green light emitting organic thin film EL device with cd / m ² or more has been developed (Appl. Phys. Lett., 51, 913 (1
987)). The distyrylbenzene compound, which is famous as a laser dye, has high fluorescence in the blue to blue-green region, and using this as a light emitting material, it was possible to obtain EL light emission of about 80 cd / m ^{2 in a} single layer. Reported (EP 0319881). Further, regarding a photoconductor characterized by containing a styryl compound, JP-A-63-63
No. 269158 and Japanese Patent Laid-Open No. 3-11355. The inventors of the present invention disclosed in Japanese Patent Laid-Open No. 2-2472
In Japanese Patent Publication No. 78, in addition to providing a styryl compound that provides high-luminance electroluminescence emission with a luminance of 1000 cd / m ² or more, the inventors have earnestly studied to develop a styryl compound with less deterioration in initial luminance.

[0003]

As a result, it has been found that a novel styryl compound having a specific substituent is suitable for the above purpose. The present invention has been completed based on such findings. That is, the present invention has the general formula (I)

[0004]

[Chemical 9]

[Wherein k, l, m and n are 0 to 5 respectively]
Indicates an integer. However, the case where k, l, m, and n are all 0 is excluded. Ar is

[0006]

[Chemical 10]

(In the formula, R ¹ represents an alkyl group having 1 to 6 carbon atoms or halogen, R ² and R ³ represent hydrogen, an alkyl group having 1 to 6 carbon atoms or halogen, and p is 1 Is an integer of 4 and q and r are integers of 0 to 4, respectively.
However, when p, q and r are plural, R ¹ , R ² and R ³ may be the same or different. ) Is shown. ] The styryl compound represented by these is provided. The present invention also provides a compound represented by the general formula (II)

[0008]

[Chemical 11]

[In the formula, R represents an alkyl group having 1 to 4 carbon atoms or a phenyl group, and Ar is as defined above. ] The arylene group-containing phosphorus compound represented by the general formula (III)

[0010]

[Chemical 12]

[In the formula, s and t each represent an integer of 0-5. However, the case where both s and t are 0 is excluded. The present invention provides a method for producing a styryl compound represented by the general formula (I) (hereinafter referred to as method A), which comprises condensing with a ketone represented by the general formula (IV).

[0012]

[Chemical 13]

[In the formula, R, s, and t are the same as described above. ] The phosphorus compound represented by the general formula (V)

[0014]

Embedded image OCH-Ar-CHO ... v

[In the formula, Ar has the same meaning as described above. ] The manufacturing method of the styryl compound shown by General formula (I) characterized by condensing with the dialdehyde represented by these (following Method B
And ) Is provided. Furthermore, the present invention provides the compound of general formula (VI)

[0016]

[Chemical 15]

[In the formula, R, k, m and Ar are the same as described above. ] The arylene group-containing phosphorus compound represented by the general formula (VII)

[0018]

[Chemical 16]

[In the formula, l and n are the same as above. The present invention provides a method for producing a styryl compound represented by the general formula (I) (hereinafter referred to as method C), which comprises condensing with a ketone represented by the formula (I), and further emits the styryl compound represented by the general formula (I). It is intended to provide an electroluminescence device made of a material.

The styryl compound represented by the above formula (I) has two methylidines (= C = CH-) in one molecule.
) Units, and due to the geometrical isomerism of this methylidin unit, there are four combinations, namely, cis-cis, trans-cis, cis-trans and trans-trans combinations, but the styryl compound of the present invention is Any of them may be used, or a mixture of geometrical isomers may be used. Particularly preferably, all are trans. Although the novel styryl compound of the present invention described above can be produced by various methods, it can be efficiently produced by the above method A, B or C of the present invention.

First, in the method A of the present invention, the objective compound is obtained by subjecting the above-mentioned arylene group-containing phosphorus compound represented by the general formula (II) to the ketone represented by the general formula (III) in a condensation reaction. A styryl compound of the general formula (I) is prepared. Here, Ar in the general formula (II) corresponds to Ar of the styryl compound to be produced. Here, Ar is, for example, a tolylene group, a xylylene group, a tetramethylphenylene group,
Ethylxylylene group, dichlorophenylene group, tetrabromophenylene group, ditertiarybutylphenylene group,
Examples thereof include a biphenylene group, a methylbiphenylene group, a dimethylbiphenylene group, a diethylmethylbiphenylene group, a dichlorobiphenylene group, a dibromobiphenylene group, a tetrachlorobiphenylene group, a ditertiarybutyldibromobiphenylene group, and an octamethylbiphenylene group. R is an alkyl group having 1 to 4 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group) and phenyl group. The arylene group containing phosphorus compound, a known method, for example Arbsov reactions: i.e. the general formula XH ₂ C-Ar -CH ₂ X [wherein, X represents a halogen atom, Ar is as defined above. ] And an aromatic bishalomethyl compound represented by the general formula (RO) ₃ P [wherein R is the same as defined above]. ] It can obtain by making the trialkyl phosphite represented by these react. Further, in the ketone of the general formula (III), the substitution numbers s and t of the cyano group are selected corresponding to the substitution numbers k, l, m and n of the cyano group of the styryl compound to be produced. The arylene group-containing phosphorus compound of the general formula (II) and the general formula (II
The condensation reaction of I) with a ketone can proceed under various conditions. As the reaction solvent used here, hydrocarbons, alcohols and ethers are preferable. Specifically, methanol; ethanol; isopropanol; butanol; 2-methoxyethanol; 1,2-dimethoxyethane; bis (2-methoxyethyl) ether; dioxane; tetrahydrofuran; toluene; xylene; dimethyl sulfoxide; N, N-dimethyl. Formamide; N
-Methylpyrrolidone; 1,3-dimethyl-2-imidazolidinone and the like. Of these, tetrahydrofuran and dimethyl sulfoxide are preferable. Further, as the condensing agent, alcoholates such as caustic soda, caustic potash, sodium amide, sodium hydride, n-butyllithium, sodium methylate and potassium-t-butoxide are used if necessary. Among them, n-butyllithium and potassium-t-butoxide are preferable. The reaction temperature varies depending on the type of reaction raw materials used and other conditions and cannot be uniquely determined, but is usually about 0 ° C to about 10 ° C.
A wide range can be selected up to 0 ° C. Particularly preferably, it is in the range of 10 ° C to 70 ° C.

The styryl compound of the present invention can be efficiently produced by the above method A, and a specific one of the styryl compounds can also be efficiently produced by the method B. In this method B, the general formula (IV)
The target styryl compound of general formula (I) is produced by subjecting the phosphorus compound represented by and the dialdehyde of general formula (V) to a condensation reaction. Here, R in the general formula (IV) is an alkyl group having 1 to 4 carbon atoms (for example,
(Methyl group, ethyl group, propyl group, butyl group) and phenyl group, and the substitution numbers s, t of the cyano group correspond to the substitution numbers k, 1, m, n of the cyano group of the styryl compound to be produced. Further, Ar in the general formula (V) corresponds to Ar of the styryl compound to be produced. The condensation reaction between the phosphorus compound of the general formula (IV) and the dialdehyde of the general formula (V) is
It can proceed under various conditions. The reaction solvent and the condensing agent which are preferably used here are the same as those used in the method A. The reaction temperature varies depending on the type of reaction raw material used and other conditions and cannot be uniquely determined, but it can be generally selected in a wide range from about 0 ° C to about 100 ° C. Particularly preferably, it is 0 ° C to 70 ° C.

The styryl compound of the present invention is obtained by the method A described above.
And B can be efficiently manufactured. Further, it can also be produced by the method C. In this method C, a target styryl compound of the general formula (I) is produced by subjecting a phosphorus compound represented by the general formula (VI) and a ketone represented by the general formula (VII) to a condensation reaction. Here, R in the general formula (VI) is an alkyl group having 1 to 4 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group) and a phenyl group, and the substitution numbers k and m of the cyano group are produced. It is selected according to the number of substitutions k and m of the cyano group of the styryl compound to be obtained. Here, as a method for producing the general formula (VI),
General formula

[0024]

[Chemical 17]

[In the formula, k, m and R are the same as described above. In the general formula OHC-Ar-CH ₃ [wherein a phosphorus compound represented by], Ar are as defined above. ] The general formula by condensing the aldehyde represented by

[0026]

[Chemical 18]

[In the formula, k, m and Ar are the same as described above. ] The styryl compound represented by this is obtained. This can be prepared according to known methods, for example by halogenation reaction with N-haloamides, especially N-chloro or N-bromo-succinamide, in the general formula

[0028]

[Chemical 19]

[Wherein X represents a halogen atom, Ar,
k and m are the same as above. ] The aromatic halomethyl compound represented by this is obtained. This halomethyl compound and the general formula (RO) ₃ P [wherein R is the same as defined above. ] It can obtain by making the trialkyl phosphite represented by these react. The above is the production method of the general formula (VI), but in the ketone of the general formula (VII), the substitution numbers l and n of the cyano group are
Is selected according to the substitution numbers l and n of the cyano group of the styryl compound (I) to be produced. The condensation reaction of the phosphorus compound of the general formula (VI) and the ketone of the general formula (VII) can proceed under various conditions. Here, the reaction solvent and the condensing agent which are preferably used are the same as those used in the method A. The reaction temperature varies depending on the type of reaction raw material used and other conditions and cannot be uniquely determined, but usually can be selected in a wide range from about 0 ° C to about 100 ° C. Particularly preferably, it is in the range of 0 ° C to 70 ° C.

Specific examples of the compound represented by the general formula (I) include those shown below.

[0031]

[Chemical 20]

[0032]

[Chemical 21]

[0033]

[Chemical formula 22]

[0034]

[Chemical formula 23]

[0035]

[Chemical formula 24]

[0036]

[Chemical 25]

However, the present invention is not limited to these.
The styryl compound of the present invention thus obtained can be effectively used as an EL device capable of emitting light with high brightness at a low voltage. The styryl compound of the present invention is E
It has an electron injection function, an electron transport function, and a light emitting function which are indispensable as a light emitting layer of an L element, and has excellent heat resistance and thin film property. Furthermore, this styryl compound has the advantages that it does not decompose or deteriorate even when heated to the vapor deposition temperature, a dense film of uniform fine crystal grains can be formed, and pinholes do not form. As described above, the compound represented by the general formula (I) of the present invention is effective as a light emitting layer in an EL device. This light-emitting layer can be formed by thinning the compound of the general formula (I) by a known method such as a vapor deposition method, a spin coating method, a casting method, or the like. preferable. Here, the molecular deposition film is a thin film formed by depositing the compound from a gas phase state, or a film formed by solidifying from a solution state or a liquid phase state of the compound, for example, a vapor deposition film or the like. Although shown, this molecular deposition film can be generally distinguished from a thin film (molecular cumulative film) formed by the LB method. Further, the light emitting layer is disclosed in JP-A-59-19.
As disclosed in Japanese Patent No. 4393 or the like, a binder such as a resin and the compound are dissolved in a solvent to form a solution, which can be formed into a thin film by a spin coating method or the like.

The thin film of the light emitting layer thus formed is not particularly limited and can be appropriately selected depending on the situation, but is usually selected in the range of 5 nm to 5 μm. The light emitting layer in this EL device has (1) an injection function capable of injecting holes from the anode or the hole injection layer and injecting electrons from the cathode or the electron injection layer when an electric field is applied, (2 ) It has a transport function to move the injected charges (electrons and holes) by the force of the electric field, and (3) provides a field for recombination of electrons and holes inside the light-emitting layer and connects it to light emission. is doing. There may be a difference between the ease of injecting holes and the ease of injecting electrons,
The transport ability represented by the mobility of holes and electrons may be large or small, but it is preferable to move one of the charges. Since the compound represented by the general formula (I) used for the light emitting layer generally has an ionization energy of less than about 6.0 eV, if an appropriate anode metal or anode compound is selected,
It is relatively easy to inject holes. The electron affinity is 2.8 eV.
Since it is larger than the above range, if an appropriate cathode metal or cathode compound is selected, it is relatively easy to inject electrons and the electron and hole transporting ability is excellent. Furthermore, since the solid-state fluorescence is strong, it has a large ability to convert the excited state formed at the time of recrystallization of electrons and holes of the compound or its associated body or crystal into light.

The structure of an EL device using the compound of the present invention has various modes. Basically, the light emitting layer is sandwiched between a pair of electrodes (anode and cathode). A hole injection layer or an electron injection layer may be interposed if necessary. Specifically, (1) anode / light-emitting layer / cathode, (2)
Anode / hole injection layer / light emitting layer / cathode, (3) anode / hole injection layer / light emitting layer / electron injection layer / cathode, (4) anode / light emitting layer / electron injection layer / cathode, etc. You can
The hole injection layer and the electron injection layer are not always necessary, but the presence of these layers further improves the light emission performance. Further, it is preferable that all of the elements having the above-mentioned constitution are supported by a substrate, and there is no particular limitation on the substrate, and the elements conventionally used for EL elements such as glass, transparent plastic, quartz and the like are used. Any thing can be used.

As the anode in this EL device, those having an electrode substance of a metal, an alloy, an electrically conductive compound having a large work function (4 eV or more) and a mixture thereof are preferably used. Specific examples of such an electrode material include A
Examples thereof include metals such as u and dielectric transparent materials such as CuI, ITO, SnO ₂ , and ZnO. The anode can be prepared by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering. When the emitted light is taken out from this electrode, it is desirable that the transmittance is higher than 10%, and the sheet resistance as an electrode is preferably several hundred Ω / □ or less. The film thickness depends on the material, but is usually 10 nm to 1 μm, preferably 10 nm to 1 μm.
It is selected in the range of 200 nm.

On the other hand, as the cathode, a material having an electrode substance of a metal, an alloy, an electrically conductive compound or a mixture thereof having a low work function (4 eV or less) is used. Specific examples of such an electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, Al / AlO ₂ , indium and the like. The cathode can be produced by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering. Further, the sheet resistance as an electrode is preferably several hundred Ω / □ or less, and the film thickness is usually 10 nm.
To 1 μm, preferably 50 to 200 nm. In this EL element, it is convenient that either the anode or the cathode is transparent or semi-transparent to allow the emitted light to pass therethrough, so that the emission efficiency of the emitted light is good.

The EL device using the compound of the present invention has various constitutions as described above, and the hole injecting layer (hole injecting and transporting layer) in the EL device having the constitution (2) or (3) is various. ) Is a layer composed of a hole transfer compound, and has a function of transferring holes injected from the anode to the light emitting layer,
By interposing this hole injection layer between the anode and the light emitting layer, many holes are injected into the light emitting layer at a lower electric field, and moreover, electrons injected from the cathode or the electron injection layer into the light emitting layer. Is a device having excellent light emitting performance, such as being accumulated in the vicinity of the interface in the light emitting layer due to the barrier of electrons existing at the interface between the light emitting layer and the hole injection layer to improve the light emitting efficiency.

The hole-transporting compound used in the hole-injection layer is disposed between two electrodes to which an electric field is applied, and when the hole is injected from the anode, the hole is appropriately emitted to the light-emitting layer. A transmissible compound, for example 10 ⁴ to 10 ⁶ V / c
When an electric field of m is applied, at least 10 ⁻⁶ cm ² / (V ·
Those having a hole mobility of (sec) are preferable. There is no particular limitation on the hole-transporting compound as long as it has the above-mentioned preferable properties, and a compound conventionally used as a hole charge-transporting material in photoconductive materials and E can be used.
Any known material used for the hole injection layer of the L element can be selected and used.

Examples of the charge transport material include triazole derivatives (described in US Pat. No. 3,112,197), oxadiazole derivatives (US Pat. No. 3,1).
89,447, etc.), imidazole derivatives (described in Japanese Patent Publication No. 37-16096, etc.), polyarylalkane derivatives (US Pat. No. 3,61).
5,402, 3,820,989, 3,5
42,544, Japanese Patent Publication No. 45-555, 5
1-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148, JP-A-55-108667, and JP-A-55-15695.
No. 3, JP-A-56-36656, etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. Nos. 3,180,729, 4,278,746 and JP-A-55-55). No. 88064, 55-8806.
5 gazette, the same 49-105537 gazette, the same 55-51.
086, 56-80051, 56-8
No. 8141, No. 57-45545, No. 54-
No. 112637, No. 55-74546, etc.), phenylenediamine derivatives (U.S. Pat. No. 3,615,044, Japanese Patent Publication Nos. 51-10105, 46-3712, 47). No. 25336, JP-A No. 54-53435, and No. 54-1105.
No. 36, No. 54-119925, etc.), arylamine derivatives (US Pat. No. 3,567,4).
No. 50, No. 3,180,703, No. 3,240,
No. 597, No. 3,658,520, No. 4,23
No. 2,103, No. 4,175,961 and No. 4,0
12,376, Japanese Patent Publication No. 49-35702,
39-27577, JP-A-55-144250.
No. 56-119132 and No. 56-224.
37, those described in West German Patent 1,110,518, etc.), amino-substituted chalcone derivatives (described in US Pat. No. 3,526,501, etc.), oxazole derivatives (US Patent) Nos. 3,257,203, etc.) and styrylanthracene derivatives (Japanese Patent Application Laid-Open No. S5-5187).
6-46234), fluorenone derivatives (described in JP-A-54-110837), hydrazone derivatives (US Pat. No. 3,717,46).
No. 2 specification, JP-A-54-59143 and JP-A-55-59143
No. 52063, No. 55-52064, No. 55
-46760 gazette, the same 55-85495 gazette, the same 5
Nos. 7-11350 and 57-148749) and stilber derivatives (Japanese Patent Laid-Open Nos. 61-210363, 61-228451, 61-14642 and 61-41). No. 72255, No. 62-47646, No. 62-36674.
No. 62-10652, No. 62-3025.
5, gazette 60-93445 gazette, gazette 60-944.
62, 60-174749 and 60-1.
75052) and the like).

These compounds can be used as a hole transfer compound, and the porphyrin compounds shown below (those described in JP-A-63-295695)
And aromatic tertiary amine compounds and styrylamine compounds (U.S. Pat. No. 4,127,412, JP-A-53-53)
27033, 54-58445, 54.
No. 149634, No. 54-64299, No. 55-79450, No. 55-144250, No. 56-119132, No. 61-29555.
8 gazette, the same 61-98353 gazette, the same 63-295.
No. 695, etc.), and it is particularly preferable to use the aromatic tertiary amine compound. Typical examples of the porphyrin compound include porphyrin; 1,10,1
5,20-Tetraphenyl-21H, 23H-porphyrin copper (II); 1,10,15,20-Tetraphenyl-21H, 23H-porphyrin zinc (II); 5,1
0,15,20-Tetrakis (pentafluorophenyl) -21H, 23H-porphyrin; Silicon phthalocyanine oxide; Aluminum phthalocyanine chloride; Phthalocyanine (metal free); Dilithium phthalocyanine; Copper tetramethylphthalocyanine; Copper phthalocyanine; Chromium phthalocyanine; Zinc phthalocyanine Lead phthalocyanine; titanium phthalocyanine oxide; magnesium phthalocyanine; copper octamethylphthalocyanine and the like. Further, as typical examples of the aromatic tertiary compound and the styrylamine compound, N, N,
N ', N'-tetraphenyl- (1,1'-biphenyl) -4,4'-diamine; N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1' -Biphenyl] -4,4'-diamine; 2,2-bis (4-
Di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl- (1,
1'-biphenyl) -4,4'-diamine; 1,1-bis (4-di-p-tolylaminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; Bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N'-di (4-methoxyphenyl)-
(1,1'-biphenyl) -4,4'-diamine; N,
N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- ( Di-p-tolylamine) -4'-
[4 (di-p-tolylamine) styryl] stilbene;
4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbene; N-phenylcarbazole and the like.

The hole injecting layer in the EL device may be composed of a single layer containing one or more of these hole transporting compounds, or a hole injecting layer containing a compound different from the above layer. It may be a stack of layers.
On the other hand, the electron injecting layer (electron injecting and transporting layer) in the EL device having the above-mentioned configuration (3) is made of an electron transfer compound and has a function of transferring the electrons injected from the cathode to the light emitting layer. There is. There is no particular limitation on such an electron transfer compound, and any compound can be selected and used from conventionally known compounds. Preferred examples of the electron transfer compound include:

[0047]

[Chemical formula 26]

Nitro-substituted fluorenone derivatives such as

[0049]

[Chemical 27]

Thiopyran dioxide derivatives such as

[0051]

[Chemical 28]

Diphenylquinone derivatives such as those described in "Polymer Preprints, Japan", Vol. 37, No. 3, page 681 (1988), or the like.

[0053]

[Chemical 29]

Compounds such as [Journal of Applied Physics, Vol. 27,
Those described on page 269 (1988), etc., and anthraquinodimethane derivatives (JP-A-57-149259, JP-A-58-55450, JP-A-61-22515).
No. 1, gazette 61-233750, gazette 63-10.
4061) and fluorenylidene methane derivatives (JP-A-60-69657 and 61).
Those described in JP-A-143764, JP-A-61-148159, etc.) and anthrone derivatives (JP-A-61-2).
No. 25151, No. 61-233750, etc.)

[0055]

[Chemical 30]

(In the formula, t-Bu represents a tert-butyl group.) Examples include oxadiazole derivatives disclosed in "Appl. Phys. Lett." Vol. 55, page 1489 (1989). be able to. Note that the hole-injection layer and the electron-injection layer are layers having any of an injection property of electric charge, a transport property, and a barrier property.
It is also possible to use an inorganic material such as a crystalline or non-crystalline material such as SiC-based or CdS-based. The hole injection layer and the electron injection layer using an organic material can be formed in the same manner as the light emitting layer, and the hole injection layer and the electron injection layer using an inorganic material can be formed by a vacuum vapor deposition method or sputtering. It is preferable to use the vacuum vapor deposition method regardless of whether organic or inorganic materials are used for the same reason as in the case of the light emitting layer.

Next, an example of a suitable method for producing an EL device using the compound of the present invention will be described for each device of each constitution. EL consisting of the above-mentioned anode / light-emitting layer / cathode
Explaining the method of manufacturing the device, first, a thin film made of a desired electrode material, for example, a material for an anode, is vapor-deposited or sputtered on a suitable substrate so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. After forming a positive electrode by a method such as the above, a thin film of a compound represented by the general formula (I), which is a light emitting material, is formed on this to form a light emitting layer. As a method for thinning the light emitting material, there are, for example, a spin coating method, a casting method, a vapor deposition method and the like, but the vapor deposition method is preferable from the viewpoint that a uniform film is easily obtained and pinholes are not easily generated. . When this vapor deposition method is used for thinning the light emitting material, the vapor deposition conditions generally differ depending on the type of organic compound used in the light emitting layer used, the target crystal structure of the molecular deposited film, the association structure, etc. Boat heating temperature 50-400 ℃, vacuum degree 1
0 ^-5 to 10 ^-3 Pa, vapor deposition rate 0.01 to 50 nm / se
c, substrate temperature −50 to + 300 ° C., film thickness 5 nm to 5
It is desirable to select it appropriately in the range of μm. Next, after forming this light-emitting layer, a thin film of a cathode material is formed thereon to a thickness of 1 μm.
Hereinafter, a desired EL element can be obtained by forming a film having a thickness of preferably 50 to 200 nm by a method such as vapor deposition or sputtering and providing a cathode. In the production of this EL element, it is possible to reverse the production order and produce the cathode, the light emitting layer and the anode in this order.

Next, a method of manufacturing an EL element composed of anode / hole injection layer / light emitting layer / cathode will be described. First, an anode is formed in the same manner as in the case of the EL element, and then,
A thin film made of a hole transfer compound is formed thereon by a vapor deposition method or the like to provide a hole injection layer. The vapor deposition conditions at this time may conform to the vapor deposition conditions for forming the thin film of the light emitting material. Next, a desired EL element is obtained by sequentially providing a light emitting layer and a cathode on the hole injecting layer in the same manner as in the case of manufacturing the EL element. Also in the fabrication of this EL element, the fabrication order can be reversed to fabricate the cathode, the light emitting layer, the hole injection layer, and the anode in this order.

Further, a method of manufacturing an EL element consisting of anode / hole injection layer / light emitting layer / electron injection layer / cathode will be described. First, in the same manner as in the case of manufacturing the EL element, an anode and a hole are formed. After sequentially providing an injection layer and a light emitting layer, a thin film made of an electron transfer compound is formed on the light emitting layer by a vapor deposition method or the like, and an electron injection layer is provided, and then, a thin film is formed.
A desired EL element can be obtained by providing the cathode in the same manner as in the case of manufacturing the EL element. In addition, this EL
Also in the fabrication of the device, the fabrication order may be reversed, and the cathode, the electron injection layer, the light emitting layer, the hole injection layer, and the anode may be fabricated in this order. Further, a method of manufacturing an EL element composed of anode / light emitting layer / electron injection layer / cathode will be described. First, similarly to the case of manufacturing the EL element, an anode and a light emitting layer are sequentially provided, and then this light emission is performed. A thin film made of an electron transfer compound is formed on the layer by a vapor deposition method or the like to provide an electron injection layer, and then a cathode is provided thereon in the same manner as in the case of manufacturing the EL element to obtain a desired EL. The device is obtained. Also in the fabrication of this EL element, the fabrication order may be reversed to fabricate the cathode, the electron injection layer, the light emitting layer, and the anode in this order.

When a direct current voltage is applied to the EL device thus obtained, a voltage of about 5 to 40 V is applied with the positive polarity of the anode and the negative polarity of the cathode. It can be observed from the side. Moreover, even if a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Furthermore, when an AC voltage is applied, the anode is + and the cathode is-.
The light is emitted only when the state becomes. The waveform of the alternating current applied may be arbitrary. Next, the light emitting mechanism of the EL device will be described by taking the case of the structure of anode / hole injecting and transporting layer / light emitting layer / cathode as an example. When a voltage is applied with the anode having a positive polarity and the cathode having a negative polarity, holes are injected from the anode into the hole injection layer by an electric field. The injected holes are transported inside the hole injecting and transporting layer toward the interface with the light emitting layer, and are injected or transported from the interface to a region where the light emitting function is exhibited (for example, the light emitting layer). On the other hand, electrons are injected from the cathode into the light emitting layer by an electric field and further transported,
It recombines with holes in a region where holes are present, that is, a region where a light emitting function is exhibited (in this sense, the region may be called a recombination region). When this recombination takes place, the molecule,
An excited state such as an associated body or a crystal is formed, and this is converted into light. The recombination region may be at the interface between the hole injecting and transporting layer and the light emitting layer, at the interface between the light emitting layer and the cathode, or at the center of the light emitting layer distant from both interfaces. This depends on the type of compound used, its association and crystal structure.

[0061]

EXAMPLES Next, the present invention will be described in more detail based on examples. Example 1 (1) Production of arylene group-containing phosphorus compound 25 g of 2,5-bis (chloromethyl) xylene and 49 g of triethyl phosphite were placed in an oil bath under an argon stream in an oil bath.
The mixture was heated and stirred at a temperature of 150 ° C. for 7 hours. Then, excess triethyl phosphite and by-produced ethyl chloride were distilled off under reduced pressure. After standing overnight, the produced white powder was recrystallized from n-hexane to obtain 46.5 g of white crystals (yield 93%). The melting point of the obtained product was 61.5-63.5 ° C. The ¹ H-NMR analysis is as follows. ¹ H-NMR (CDCl ₃ ) δ = 6.9 ppm (s; 2H, central xylene ring-H) δ = 3.9 ppm (q; 8H, methylene-CH ₂ ethoxy group) δ = 3.1 ppm (d; 4H ^{, J = 20Hz (31 P- 1} H _{coupling) P-CH 2) δ =} 2.2ppm (s; 6H, xylene ring _{-CH 3) δ = 1.1ppm (t} ; 12H, ethoxy group methyl -CH ₃ From the above results, it was confirmed that the above product was an arylene group-containing phosphorus compound (phosphonate) represented by the following formula.

[0062]

[Chemical 31]

(2) Preparation of styryl compound 2.4 g of the phosphonate obtained in the above (1) and 2.7 g of p-cyanobenzophenone were mixed with dimethyl sulfoxide 100
It was dissolved in milliliter, potassium-t-butoxide (1.4 g) was added thereto, and the mixture was stirred under an argon stream at room temperature for 6 hours and then left overnight. Methanol 30 was added to the obtained mixture.
0 ml was added and the precipitated crystals were filtered. Then, the filtered product was subjected to column purification (silica gel column using chloroform as a developing solvent), which resulted in a pale yellow powder.
0.5 g was obtained (17% yield). The melting point of this product is 253.
Was ~ 256 ° C. The ¹ H-NMR analysis of this powder is as follows. ¹ H-NMR (CDCl ₃ ) δ = 7.5 to 6.9 ppm (m; 20H, aromatic ring) δ = 6.5 ppm (s; 2H, methylidin-CH = C =) δ = 2.0 ppm (s; 6H, xylene ring -CH ₃₎ further the elemental analysis results are as follows as the composition formula C ₃₈ H ₂₈ N _2. The values in parentheses are theoretical values. C: 89.21% (89.03%) H: 5.40% (5.51%) N: 5.27% (5.46%) Also, infrared (IR) absorption spectrum (KBr tablet method)
Is as follows.

[0064]

[Chemical 32]

From the mass spectrum, the main molecular ion peak of the target substance was m / Z = 512. From the above, the light yellow powder which is the above product has the following formula:

[0066]

[Chemical 33]

It was confirmed to be 2,5-bis [2- (4-cyanophenyl) -2-phenylvinyl] xylene represented by:

Example 2 (1) Production of arylene group-containing phosphorus compound 9.0 g of 4,4′-bis (bromomethyl) biphenyl and 11 g of triethyl phosphite were placed in an oil bath under an argon stream at a temperature of 140 ° C. for 6 hours. The mixture was heated and stirred. afterwards,
Excessive triethyl phosphite and by-produced ethyl bromide were distilled off under reduced pressure. After standing overnight, white crystals 9.5g (yield 80%
) Got. The melting point of the obtained product is 97.0-100.0 ° C.
Met. The results of ¹ H-NMR analysis are as follows. ¹ H-NMR (CDCl ₃ ) δ = 7.0 to 7.6 ppm (m; 8H, biphenylene ring-H) δ = 4.0 ppm (q; 8H, ethoxy group methylene-CH ₂ ) δ = 3.1 ppm ( d; 4H, J = 20Hz ( 31 P- 1 H _{coupling) P-CH 2) δ =} 1.3ppm (t; from 12H, ethoxy group methyl -CH ₃₎ As a result, the product described above, the following It was confirmed to be an arylene group-containing phosphorus compound (phosphonate) represented by the formula.

[0069]

[Chemical 34]

(2) Preparation of styryl compound 1.4 g of the phosphonate obtained in (1) above and 1.4 g of p-cyanobenzophenone were dissolved in 60 ml of dimethyl sulfoxide, and 0.7 g of potassium t-butoxide was dissolved.
Was added, and the mixture was stirred at room temperature under an argon stream and then left overnight. The solvent of the obtained mixture was distilled off, 200 ml of methanol was added, and the precipitated crystals were filtered. Then, the filtered product was subjected to column purification (silica gel column using chloroform as a developing solvent), and as a result, 0.3 g of a pale yellow powder was obtained (yield 18%). The melting point of the obtained product was 257 to 261 ° C. The results of ¹ H-NMR analysis of this powder are as follows. ¹ H-NMR (CDCl ₃ ) δ = 6.8 to 7.5 ppm (m; 28H, aromatic ring and methylidin-CH = C =) Further, the elemental analysis result is as follows as a composition formula C ₄₂ H ₂₈ N _2. Is. The values in parentheses are theoretical values. C: 89.74% (89.97%) H: 4.83% (5.03%) N: 4.77% (5.000%) Also, infrared (IR) absorption spectrum (KBr tablet method)
Is as follows.

[0071]

[Chemical 35]

From the mass spectrum, the main molecular ion peak of the target substance was m / Z = 560. From the above, the light yellow powder which is the above product has the following formula:

[0073]

[Chemical 36]

It was confirmed to be a 4,4'-biphenylene dimethylidene derivative represented by:

Example 3 The procedure of Example 2 was repeated, except that the phosphonate obtained in (1) in (2) of Example 2 was replaced by a phosphonate ester of 2,2'-dimethylbiphenyl. did. After distilling off the solvent of the obtained mixture, methanol 2
00 ml was added, and the precipitated crystals were filtered. Then, the filtered product was subjected to column purification (silica gel column using chloroform as a developing solvent), and as a result, white powder
0.6 g was obtained (20% yield). The melting point of the obtained product was 193-195 ° C. Moreover, ¹ H- of this powder
The NMR analysis results are as follows. ¹ H-NMR (CDCl ₃ ) δ = 7.0 to 7.6 ppm (m; 24H, central biphenylene and terminal phenyl) δ = 6.6 ppm (s; 2H, vinyl) δ = 1.8 ppm (s; 6H, Methyl group) Furthermore, the elemental analysis results are as follows with the composition formula C ₄₄ H ₃₂ N ₂ . The values in parentheses are theoretical values. C: 89.51% (89.76%) H: 5.53% (5.48%) N: 4.46% (4.76%) Also, infrared (IR) absorption spectrum (KBr tablet method)
Is as follows.

[0076]

[Chemical 37]

From the mass spectrum, the main molecular ion peak of the target substance was detected at m / Z = 588. From the above, the light yellow powder which is the above product has the following formula:

[0078]

[Chemical 38]

2,2'-dimethyl-4,4 'represented by
-It was confirmed to be a biphenylene dimethylidene derivative.

Example 4

Example 2 was repeated except that the phosphonate obtained in (1) in (2) of Example 2 was replaced by a phosphonate ester of 2,2 ', 5,5'-tetrachlorobiphenyl. The same operation was performed. After distilling off the solvent of the obtained mixture, 200 ml of methanol was added,
The precipitated crystals were filtered. Then, the filtered product was subjected to column purification (silica gel column using chloroform as a developing solvent), and as a result, 1.7 g of white powder was obtained (yield 6
2%). The melting point of the obtained product was 210 to 212 ° C. The results of ¹ H-NMR analysis of this powder are as follows. ¹ H-NMR (CDCl ₃ ) δ = 7.0 to 7.6 ppm (m; 22H, central biphenylene and terminal phenyl) δ = 6.8 ppm (s; 2H, vinyl) Further, the elemental analysis result is the composition formula C _42. it is as follows as H ₂₄ Cl ₄ N _2. The values in parentheses are theoretical values. C: 72.41% (72.22%) H: 3.59% (3.46%) N: 3.79% (4.01%) Also, infrared (IR) absorption spectrum (KBr tablet method)
Is as follows.

[0082]

[Chemical Formula 39]

From the mass spectrum, the main molecular ion peak of the target substance was detected at m / Z = 698. From the above, the light yellow powder which is the above product has the following formula:

[0084]

[Chemical 40]

It was confirmed to be a 2,2 ', 5,5'-tetrachloro-4,4'-biphenylene dimethylidene derivative represented by:

Example 5 (EL device made of styryl compound) ITO was formed on a glass substrate of 25 mm × 75 mm × 1.1 mm.
A film formed by vapor deposition to a thickness of 100 nm (HOY
A) was used as a transparent support substrate. Then, the transparent supporting substrate was ultrasonically cleaned in propyl alcohol, pure water, and isopropyl alcohol in this order, and then dry nitrogen was blown to remove the solvent from the substrate surface. Further, the cleaned substrate was treated with a UV / O ₃ dry stripper (manufactured by Samco International) for 3 minutes to remove organic substances on the substrate surface. This transparent support substrate was fixed to a substrate holder of a commercially available vapor deposition device (manufactured by Nippon Vacuum Technology Co., Ltd.), and was placed on a resistance heating boat made of molybdenum in which N, N'-bis (3-methylphenyl) -N, N'-. 200 mg of biphenyl- [1,1'-biphenyl] -4,4'-diamine (TPD)
4,4'-bis [2- (4-cyanophenyl) -2-obtained in Example 2 was placed in another molybden boat.
Phenylvinyl] biphenyl (CPPVBi) 200
After adding mg, the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. After that, the boat containing TPD is heated to 215 to 220 ° C., TPD is vapor-deposited on the transparent support substrate at a vapor deposition rate of 0.1 to 0.3 nm / sec to form a hole injection layer having a film thickness of 60 nm. Let The substrate temperature at this time was room temperature. Then, without taking this out from the vacuum chamber, 80n of CPPVBi was used as a light emitting layer from another boat on the hole injection layer.
m vapor deposition was performed. Regarding the vapor deposition conditions, the boat temperature was 330 ° C., the vapor deposition rate was 0.2 to 0.4 nm / sec, and the substrate temperature was room temperature. This was taken out of the vacuum chamber, a stainless steel mask was placed on the light emitting layer, and it was fixed again to the substrate holder. Next, 1 g of magnesium ribbon was put in a resistance heating boat made of molybden, and 500 mg of indium was attached to another resistance heating boat made of molybden. After that, the vacuum chamber was depressurized to 2 × 10 ⁻⁴ Pa, and then indium was vapor-deposited at a deposition rate of 0.03 to 0.08 nm / sec, and at the same time magnesium of 1.7 to 2.8 nm / sec was supplied from the other boat. Deposition started at the deposition rate. The temperature of the boat is 800 ℃, 50 with indium and magnesium, respectively.
It was about 0 ° C. Under the above conditions, a mixed metal electrode of magnesium and indium was laminated and vapor-deposited on the light emitting layer in a thickness of 150 nm to form a counter electrode, thereby forming an element. ITO electrode as anode,
When a DC voltage of 10 V is applied to the obtained device with a mixed metal electrode of magnesium and indium as a cathode, a current of about 330 mA / cm ² flows, and YellowGree in chromaticity coordinates
n emission was obtained. The peak wavelength was 563 nm by spectroscopic measurement, and the emission brightness was 2000 cd / cm ² or more.
In addition, the obtained EL element was driven with constant current (1.0 mA
/ Cm ² ) in nitrogen to measure the initial luminance deterioration. Using the ITO electrode as the anode and the mixed metal electrode of magnesium and indium as the cathode, a current was passed through the obtained device and the brightness and the applied voltage were measured at regular intervals. As a result, there was a 20% decrease in one hour. After that, stable light emission was obtained (see FIG. 1).

Example 6 (EL device made of styryl compound) ITO was formed on a glass substrate of 25 mm × 75 mm × 1.1 mm.
A film formed by vapor deposition to a thickness of 100 nm (HOY
A) was used as a transparent support substrate. UV this transparent support substrate
UV ozone cleaning was performed for 2 minutes using an ozone treatment device (manufactured by Nippon Battery Co., Ltd.). Then, it was fixed to a substrate holder of a commercially available vapor deposition apparatus (manufactured by Nippon Vacuum Technology Co., Ltd.), 200 mg of TPD was put in a resistance heating boat made of molybdenum, and another molybdenum boat obtained in Example 1 was used. 5-bis [2
-(4-Cyanophenyl) -2-phenylvinyl] xylene (CPPVX) (200 mg) was added and the vacuum chamber was set to 1 × 1.
The pressure was reduced to 0 ^-4 Pa. After that, the boat containing TPD is heated to 215 to 220 ° C., and TPD is deposited at a deposition rate of 0.
A film thickness of 6 is obtained by vapor deposition on a transparent support substrate at 1 to 0.3 nm / sec.
A 0 nm hole injection layer was formed. The substrate temperature at this time was room temperature. Then, without removing this from the vacuum chamber, the CPP from another boat was placed on the hole injection layer.
80 nm of VX was vapor-deposited as a light emitting layer. The vapor deposition conditions are a boat temperature of 260 ° C. and a vapor deposition rate of 0.2 to 0.4n.
m / sec, the substrate temperature was room temperature. This was taken out of the vacuum chamber, a stainless steel mask was placed on the light emitting layer, and it was fixed again to the substrate holder. Next, 1 g of magnesium ribbon was put into a resistance heating boat made of molybden, and 500 mg of indium was attached to another resistance heating boat made of molybden. After that, set the vacuum chamber to 2 × 10 ^-4 P
After reducing the pressure to a, the indium content was reduced to 0.03 to 0.08 nm.
At the same time, the vapor deposition rate of 1.7 to 2.8 nm / sec was started from the other boat at the same time. The boat temperature was about 800 ° C. and 500 ° C., respectively, for boats containing indium and magnesium. Under the above conditions, a mixed metal electrode of magnesium and indium was laminated and vapor-deposited on the light emitting layer in a thickness of 150 nm to form a counter electrode, thereby forming an element. When a DC voltage of 7.5 V is applied to the obtained device with an ITO electrode as an anode and a mixed metal electrode of magnesium and indium as a cathode, a current flows at about 12 mA / cm ² , emission luminance of 135 cd / cm ² , and chromaticity coordinates. Yellow
I got ish Green luminescence. Peak wavelength is 53 from spectroscopic measurement
It was 0 nm. The EL device thus obtained was subjected to constant current driving (1.0 mA / cm ² ) in nitrogen to measure deterioration of initial luminance. Using the ITO electrode as an anode and the mixed metal electrode of magnesium and indium as a cathode, a current was passed through the obtained device and the brightness and the applied voltage were measured at regular time intervals. As a result, there was a 25% decrease in one hour. After that, stable light emission was obtained.

Example 7 A phosphonate ester of 2,2′-dimethylbiphenyl was used in place of the phosphonate obtained in (1) in (2) of Example 2 and 4, 4 was used in place of p-cyanobenzophenone. The same operation as in Example 2 was carried out except that 4′-dicyanobenzophenone was used. After distilling off the solvent of the obtained mixture, 200 ml of methanol was added,
The precipitated crystals were filtered. Then, the filtered product was subjected to column purification (silica gel column using methylene chloride as a developing solvent), and as a result, 0.5 g of a white powder was obtained (yield 1
9%). The melting point of the obtained product is 206.0 to 207.0 ° C.
Met. The results of ¹ H-NMR analysis of this powder are as follows. ¹ H-NMR (CDCl ₃ ) δ = 6.8 to 7.6 ppm (m; 22H, central biphenylene and terminal phenyl) δ = 6.5 ppm (s; 2H, vinyl) δ = 1.8 ppm (s; 6H, Methyl group) Furthermore, the elemental analysis results are as follows with the composition formula C ₄₆ H ₃₀ N ₄ . The values in parentheses are theoretical values. C: 86.27% (86.50%) H: 5.01% (4.73%) N: 8.54% (8.77%) Also, infrared (IR) absorption spectrum (KBr tablet method)
Is as follows.

[0089]

[Chemical 41]

From the mass spectrum, the main molecular ion peak of the target substance was detected at m / Z = 638. From the above, the white powder which is the above product has the following formula:

[0091]

[Chemical 42] It was confirmed that the derivative was a 2,2′-dimethyl-4,4′-biphenylene dimethylidene derivative represented by

Comparative Example 1 The following styryl compound (A) was used instead of CPPVBi.

[0093]

[Chemical 43]

An EL device was prepared in the same manner as in Example 5 except that was used. The initial luminance deterioration of the obtained EL device was measured by the same method as in Example 5. As a result, there was a decrease of 80% in 1 hour, and the initial luminance was significantly deteriorated (see FIG. 1).

[0095]

INDUSTRIAL APPLICABILITY The styryl compound of the present invention is a novel compound, and since it has a cyano group, it has excellent thermal stability. Therefore, the EL device made of the styryl compound can suppress the initial luminance deterioration to about 20% and maintain stable light emission thereafter. Therefore, the styryl compound of the present invention can be expected to be effectively used as various light emitting materials including a light emitting material for organic EL.

[Brief description of drawings]

FIG. 1 is a graph showing changes in relative luminance of light emission with time.

[Explanation of symbols]

1 shows changes with time of light emission of the EL device manufactured in Example 5. 2 shows the time-dependent change in the light emission of the EL element manufactured in Comparative Example 1.

Claims (5)

[Claims] 1. A compound represented by the general formula (I): [In formula, k, l, m, and n show the integer of 0-5, respectively. However, the case where k, l, m, and n are all 0 is excluded.
Ar is the following (In the formula, R ¹ represents an alkyl group having 1 to 6 carbon atoms or halogen, R ² and R ³ represent hydrogen, an alkyl group having 1 to 6 carbon atoms or halogen, and p is 1 to 4; Integers, q and r each represent an integer of 0 to 4, provided that p and
When q and r are plural, R ¹ , R ² and R ³ may be the same or different. ) Is shown. ] The styryl compound represented by these. 2. A compound represented by the general formula (II): [In formula, R shows a C1-C4 alkyl group or a phenyl group, and Ar is the same as the above. ] The arylene group-containing phosphorus compound represented by the general formula (III) [In the formula, s and t each represent an integer of 0 to 5. However,
The case where both s and t are 0 is excluded. ] It is condensed with the ketone represented by these, The manufacturing method of the styryl compound of Claim 1 characterized by the above-mentioned. 3. A compound represented by the general formula (IV): [In the formula, R, s, and t are the same as described above. A phosphorus compound represented by the following general formula (V): embedded image OHC—Ar—CHO (v) [wherein, Ar is as defined above]. ] It is condensed with the dialdehyde represented by these, The manufacturing method of the styryl compound of Claim 1 characterized by the above-mentioned. 4. A compound represented by the general formula (VI): [In the formula, R, k, m and Ar are the same as described above. ] The arylene group-containing phosphorus compound represented by the general formula (VII) [In formula, l and n are the same as the above. ] It is condensed with the ketone represented by these, The manufacturing method of the styryl compound of Claim 1 characterized by the above-mentioned. 5. An electroluminescent device comprising the styryl compound according to claim 1 as a light emitting material.