JP2006056821A - Fluorene compound, method for producing the same, fluorene polymer, method for producing the same and organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a new fluorene compound that has electron transport property, excellent luminescence property and is suitably useful as an organic material for constituting a luminescent layer in an organic electroluminescent element and a fluorene polymer, to provide a method for producing them and an organic electroluminescent element having excellent luminescence property and durability. <P>SOLUTION: The fluorene compound is represented by a specific chemical formula. The fluorene compound comprises a specific repeating unit. The organic electroluminescent element has a luminescent layer formed from a specific fluorene compound or a specific fluorene polymer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fluorene compound, a production method thereof, a fluorene polymer, a production method thereof, and an organic electroluminescence device, and more specifically, a fluorene compound and a fluorene compound that are suitably used as an organic material constituting a light emitting layer in the organic electroluminescence device. The present invention relates to a coalescence, a fluorene compound used as a raw material for obtaining the fluorene polymer, a production method thereof, and an organic electroluminescence element.

Prior art information relating to the invention of this application includes the following.
JP 2002-293888 A

  An organic electroluminescence element (hereinafter also referred to as “organic EL element”) can be driven by a DC voltage, is a self-luminous element, has a wide viewing angle, high visibility, and a response speed. Since it has excellent characteristics such as high speed, it is expected as a next-generation display element, and its research is being actively conducted.

  Conventionally, as an organic EL element, a single layer structure in which a light emitting layer made of an organic material is formed between an anode and a cathode, a structure having a hole transport layer between an anode and a light emitting layer, a cathode Multi-layer structures such as those having an electron transport layer between the light-emitting layer and the light-emitting layer are known, and these organic EL elements each include an electron injected from the cathode and a hole injected from the anode. However, light is emitted by recombination in the light emitting layer.

The light emitting layer constituting the organic EL element is required to have high light emission efficiency. As a method for obtaining high luminous efficiency in the light emitting layer, there is a method of approximating the carrier balance of holes and electrons in the light emitting layer to 1: 1, but it is widely used as a material for forming the light emitting layer. Polymer materials such as poly (phenylene) vinylene (PPV) and polyfluorene, which have poor electron transport properties, cannot realize high-efficiency light emission.
Recently, Chem. Mater. 15, 269 (2003) reported that an attempt was made to improve carrier balance by incorporating oxadiazole, which is an electron transporting material, into the side chain of polyfluorene. It is desired.

The present invention has been completed as a result of repeated research on the organic material constituting the light emitting layer in the organic EL element in view of the above circumstances, and its first object is to have an electron transporting property and to be excellent. An object of the present invention is to provide a novel fluorene compound having a light emitting property and suitable for use as an organic material constituting a light emitting layer in an organic electroluminescence device, and a method for producing the same.
A second object of the present invention is a raw material for obtaining a polymer that has an electron transporting property and has excellent light emission characteristics and can be suitably used as an organic material constituting a light emitting layer in an organic electroluminescence element. It is an object to provide a novel fluorene compound that can be used as a method and a method for producing the same.
The third object of the present invention is to provide a novel fluorene polymer having an electron transporting property and an excellent light emitting property, and can be suitably used as an organic material constituting a light emitting layer in an organic electroluminescence device, and the same It is to provide a manufacturing method.
A fourth object of the present invention is to provide an organic electroluminescence device having excellent light emission characteristics.

  The first fluorene compound of the present invention is represented by the following general formula (1-1).

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. m is an integer of 0 to 5, and n is an integer of 0 to 5. ]

  The first fluorene compound production method of the present invention comprises reacting a lithium phenylfluorene compound represented by the following formula (A) with a compound represented by the following general formula (A) in the presence of a solvent. To obtain the first fluorene compound.

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. m is an integer of 0 to 5, and n is an integer of 0 to 5. ]

  The second fluorene compound of the present invention is represented by the following general formula (1-2).

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. X ¹ represents a halogen atom. m is an integer of 0 to 5, and n is an integer of 0 to 5. ]

  The production method of the second fluorene compound of the present invention comprises reacting the first fluorene compound represented by the general formula (1-1) with halogen in the presence of iron chloride and a solvent. A second fluorene compound is obtained.

  The fluorene polymer of the present invention is characterized by comprising a repeating unit represented by the following general formula (2).

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. R ³ and R ⁴ each independently represents an alkyl group or an aryl group, and may be the same or different from each other. R ³ and R ⁴ may be bonded to each other to form a ring structure. Furthermore, each of the alkyl group and aryl group representing R ³ and R ⁴ may be substituted or unsubstituted. m is an integer of 0 to 5, and n is an integer of 0 to 5. ]

  The manufacturing method of the fluorene polymer of this invention is the 2nd fluorene compound represented by the said general formula (1-2), the compound represented by the following general formula (B), and the following general formula (C). The fluorene polymer is obtained by reacting the represented compound with a catalyst and a solvent.

[Wherein X ² represents a halogen atom. ]

[Wherein, R ³ and R ⁴ each independently represent an alkyl group or an aryl group, and may be the same or different from each other. R ³ and R ⁴ may be bonded to each other to form a ring structure. Furthermore, each of the alkyl group and aryl group representing R ³ and R ⁴ may be substituted or unsubstituted. ]

  The organic electroluminescence device of the present invention is characterized by having a light emitting layer formed of the first fluorene compound or the fluorene polymer.

  The first fluorene compound of the present invention has an electron transport property due to its chemical structure, high electrical stability, and excellent light emission characteristics. Therefore, the material constituting the light emitting layer in the organic EL device It is suitable as.

  According to the method for producing a fluorene compound of the present invention, the first fluorene compound having an electron transporting property and excellent light emission characteristics and useful as an organic material for forming a light emitting layer in an organic EL device is produced. can do.

  The second fluorene compound of the present invention has a chemical structure that exhibits electron transport properties and excellent light emission characteristics, and has a reactive group, and therefore, as a material constituting a light emitting layer in an organic EL device. It is used as a raw material for obtaining a suitable fluorene polymer.

  According to the second method for producing a fluorene compound of the present invention, a fluorene polymer having an electron transporting property and an excellent light emitting property and useful as an organic material for forming a light emitting layer in an organic EL device is obtained. The fluorene compound used as a raw material for obtaining can be manufactured.

  The fluorene polymer of the present invention is suitable as a material constituting a light emitting layer in an organic EL device because it has an electron transport property due to its chemical structure, high electrical stability, and excellent light emission characteristics. It is.

  According to the method for producing a fluorene polymer of the present invention, a fluorene polymer having an electron transporting property and excellent emission characteristics and useful as an organic material for forming a light emitting layer in an organic EL device is produced. be able to.

  Since the organic electroluminescent device of the present invention has a light emitting layer made of the first fluorene compound or fluorene polymer, excellent light emission characteristics can be obtained.

  Hereinafter, the present invention will be described in detail.

<Fluorene compound>
[First fluorene compound]
The 1st fluorene compound of this invention consists of a fluorene compound represented by the said general formula (1-1).

In the general formula (1-1) representing the first fluorene compound, R ¹ and R ² each independently represent a monovalent organic group, which may be the same or different from each other. It is preferable that
Specific examples of the monovalent organic group representing the group R ¹ and the group R ² include alkyl groups such as a methyl group, an ethyl group, and a t-butyl group. It is preferably an alkyl group of 8, more preferably a methyl group.
M and n are each independently an integer of 0 to 5, and may be the same or different from each other, but are preferably the same, and particularly preferably 3.

As a preferable specific example of the first fluorene compound, in general formula (1-1), m and n are both 3, and R ¹ and R ² are respectively located at the 2, 4 and 6 positions of the phenyl ring. A compound having a structure in which it is bonded and is a methyl group is exemplified.

  Such a first fluorene compound includes a lithium phenylfluorene compound represented by the above formula (A) (hereinafter also referred to as “specific lithium fluorene compound”) and a compound represented by the above general formula (A). (Hereinafter, also referred to as “specific boron compound”) can be produced by a method of reacting in the presence of a solvent.

  The specific boron compound is a boron derivative, and specific examples thereof include dimesityl boron fluoride.

  In such a production method, the ratio between the specific lithium fluorene compound as the raw material and the specific boron compound is such that the number of moles of the specific boron compound is twice or more the number of moles of the specific lithium fluorene compound. Is needed.

  The solvent is not particularly limited as long as it is an inert solvent that does not significantly inhibit the reaction between the specific lithium fluorene compound and the specific boron compound. For example, tetrahydrofuran, diethyl ether, and the like can be preferably used.

  In the first method for producing a fluorene compound, the reaction between the specific lithium fluorene compound and the specific boron compound is usually a reaction solution under the condition of a temperature of −78 ° C., and the temperature of the reaction solution is returned to room temperature. , By stirring for several hours under the temperature condition.

  The first fluorene compound as described above can be suitably used alone as a material for forming a light emitting layer in an organic EL device.

  This first fluorene compound is usually used as a light emitting layer forming solution by dissolving in a suitable organic solvent. This light emitting layer forming liquid is applied to the surface of the substrate on which the light emitting layer is to be formed, and an organic solvent is removed from the obtained coating film to form a light emitting layer in the organic EL device. .

The organic solvent for preparing the light emitting layer forming liquid is not particularly limited as long as it can dissolve the first fluorene compound. Specific examples thereof include halogenated hydrocarbons such as chloroform, chlorobenzene, and tetrachloroethane. Amide solvents such as dimethylformamide and N-methylpyrrolidone, cyclohexanone, ethyl lactate, propylene glycol methyl ether acetate, ethyl ethoxypropionate, and methyl amyl ketone. These can be used alone or in combination of two or more.
Among these, it is preferable to use an organic solvent having an appropriate evaporation rate, specifically, an organic solvent having a boiling point of about 70 to 200 ° C. in that a thin film having a uniform thickness can be obtained.

The amount of the organic solvent used varies depending on the type of the first fluorene compound, but is usually an amount such that the concentration of the first fluorene compound is 0.5 to 10% by mass.
Moreover, as means for applying the light emitting layer forming liquid, for example, a spin coating method, a dipping method, a roll coating method, an ink jet method, a printing method, or the like can be used.

  Such a first fluorene compound has a fluorescence emission characteristic, and has an electron transporting property from its chemical structure, a high electrical stability, and an excellent emission characteristic. Therefore, it is suitable as a material constituting the light emitting layer in the organic EL element, and according to the first fluorene compound, the light emitting layer in the organic EL element can be easily formed by a wet method.

[Second fluorene compound]
The 2nd fluorene compound of this invention consists of a fluorene compound represented by the said General formula (1-2), and is obtained by making a 1st fluorene compound and halogen react.

In the general formula (1-2) representing the second fluorene compound, R ¹ and R ² each independently represent a monovalent organic group, which may be the same or different from each other, but are the same It is preferable that
Specific examples of the monovalent organic group representing the group R ¹ and the group R ² include alkyl groups such as a methyl group, an ethyl group, and a t-butyl group. It is preferably an alkyl group of 8, more preferably a methyl group.
M and n are each independently an integer of 0 to 5, and may be the same or different from each other, but are preferably the same, and particularly preferably 3.

In the general formula (1-2), X ¹ represents a halogen atom, and particularly preferably a bromine atom.

As a preferable specific example of the second fluorene compound, in the general formula (1-2), m and n are both 3, and R ¹ and R ² are respectively positioned at the 2, 4 and 6 positions of the phenyl ring. A compound having a structure in which it is bonded, is a methyl group, and X ¹ is a bromine atom.

  Such a second fluorene compound can be produced by a method in which the first fluorene compound and halogen are reacted in the presence of iron chloride and a solvent.

  In such a production method, the ratio between the first fluorene compound as a raw material and the halogen is required such that the number of moles of halogen is twice or more the number of moles of the first fluorene compound. .

  Moreover, although the usage-amount of iron chloride is not specifically limited, Since reaction can be advanced reliably, it is preferable that it is 0.01-10 mol% with respect to 1 mol of halogens.

  The solvent is not particularly limited as long as it is an inert solvent that does not significantly inhibit the reaction between the first fluorene compound and halogen. For example, chloroform, carbon tetrachloride, and the like can be preferably used.

  In the method for producing the second fluorene compound, the reaction between the first fluorene compound and the halogen is usually carried out under reflux, and the reaction time is preferably selected from the range of 5 to 20 hours.

  Such a second fluorene compound is formed by bonding a reactive group to the first fluorene compound described above, and has a chemical structure in which an electron transport property and excellent light emission characteristics are expressed, and is reactive. Since it has a group, it is used as a raw material for obtaining a fluorene polymer suitable as a material constituting a light emitting layer in an organic EL device described later.

<Fluorene polymer>
The fluorene polymer of the present invention is also referred to as a fluorene polymer (hereinafter referred to as “specific fluorene polymer”) composed of the repeating unit represented by the general formula (2) (hereinafter also referred to as “specific repeating unit”). ).

In the general formula (2) indicating the specific repeating unit constituting the specific fluorene polymer, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. Are preferably the same.
Specific examples of the monovalent organic group representing the group R ¹ and the group R ² include alkyl groups such as a methyl group, an ethyl group, and a t-butyl group. It is preferably an alkyl group of 8, more preferably a methyl group.
M and n are each independently an integer of 0 to 5, and may be the same or different from each other, but are preferably the same, and particularly preferably 3.

In the general formula (2), R ³ and R ⁴ each independently represent an alkyl group or an aryl group, and may be the same or different from each other, but are preferably the same.
The alkyl group and aryl group representing the group R ³ and the group R ⁴ may be substituted or unsubstituted, and specific examples of the alkyl group include a butyl group, a hexyl group, an octyl group, Examples thereof include an ethylhexyl group, and examples of the aryl group include a phenyl group, a tolyl group, and a t-butylphenyl group.
Furthermore, the group R ³ and the group R ⁴ may be bonded to each other to form a ring structure.

As a preferred specific example of the specific fluorene polymer, in general formula (2), m and n are both 3, and R ¹ and R ² are bonded to positions 2, 4 and 6 of the phenyl ring, respectively. And a polymer composed of a repeating unit having a methyl group and R ³ and R ⁴ being an octyl group.

  The average molecular weight of the specific fluorene polymer is appropriately selected according to the purpose of use, but in terms of obtaining good mechanical properties, the polystyrene-equivalent weight average molecular weight by gel permeation chromatography is 2000 to 1000000. It is preferable that it is preferably 5,000 to 500,000, particularly in terms of obtaining solubility and processing characteristics.

  Such a specific fluorene polymer includes a second fluorene compound, a compound represented by the general formula (B) (hereinafter also referred to as “specific aminophenylfluorene compound”), and the general formula (C ) (Hereinafter also referred to as “specific boronic ester fluorene compound”) in the presence of a catalyst and a solvent.

The specific aminophenylfluorene compound is a fluorene derivative in which two groups X ² are halogen atoms. Specific examples thereof include 9,9-bis (4-diphenylaminophenyl) -2,7-dibromofluorene, 9 , 9-bis (3-methyldiphenylaminophenyl) -2,7-dibromofluorene, 9,9-bis (3-methoxydiphenylaminophenyl) -2,7-dibromofluorene, 9,9-bis (4-methoxy) And diphenylaminophenyl) -2,7-dibromofluorene.

  Moreover, as a specific example of a specific boronic acid ester fluorene compound, 9,9-dioctyl-2,7-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) Fluorene, 9,9-dibutyl-2,7-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) fluorene, 9,9-dihexyl-2,7-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) fluorene, 9,9-diethylhexyl-2,7-bis (4,4,5,5-tetramethyl- 1,3,2-dioxaborolan-2-yl) fluorene, 9,9-diphenyl-2,7-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) fluorene 9,9-ditolyl-2 7-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) fluorene, 9,9-di-t-butylphenyl-2,7-bis (4,4,5 , 5-tetramethyl-1,3,2-dioxaborolan-2-yl) fluorene and the like.

  In such a production method, the ratio of the second fluorene compound as a raw material, the specific aminophenylfluorene compound, and the specific boronic ester fluorene compound is such that the number of moles of the specific aminophenylfluorene compound is the first. The number of moles of the second fluorene compound is required to be at least the number of moles of the second fluorene compound, and the number of moles of the specific boronic ester fluorene compound is required to be at least twice the number of moles of the second fluorene compound.

  As the catalyst, for example, a divalent palladium compound such as palladium acetate, or a zero-valent palladium compound such as tris (benzylideneacetone) palladium or tetrakis (triphenylphosphine) palladium is preferably used.

  The amount of such a palladium compound used is not particularly limited, but the reaction can proceed reliably, so that the range of 0.1 to 1.5 mol with respect to the total total number of moles of compounds subjected to the reaction. It is preferable that

  As the solvent, a mixed solvent formed by combining an organic solvent and an alkaline aqueous solution is used.

  Examples of the organic solvent include ethers such as dimethoxyethane, dioxane and tetrahydrofuran, hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol and t-butyl alcohol. These can be used alone or in combination of two or more.

  Examples of the alkaline aqueous solution include aqueous solutions of amines such as tetraethylammonium hydroxide, aqueous solutions of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and aqueous solutions of alkali metal carbonates such as sodium carbonate and potassium carbonate.

  Preferable specific examples of the solvent include a mixed solvent of toluene as an organic solvent and a sodium carbonate aqueous solution as an alkaline aqueous solution.

  The amount of such a solvent used varies depending on the type of compound to be subjected to the reaction, but is usually such an amount that the total total concentration of the compounds to be subjected to the reaction is 5 to 30% by mass.

In the method for producing the specific fluorene polymer, the reaction of the second fluorene compound, the specific aminophenyl fluorene compound and the specific boronic acid ester fluorene compound is usually carried out under normal pressure.
As specific reaction conditions, for example, the reaction temperature is preferably selected from the range of 50 to 150 ° C., more preferably 60 to 120 ° C., and the reaction time is preferably selected from the range of 10 to 100 hours. do it.

  In this production method, the end of the reaction product obtained by the reaction of the second fluorene compound, the specific aminophenylfluorene compound, and the specific boronic acid fluorene compound is replaced with an arbitrary aromatic compound. It is preferable to do this, and thereby, a more excellent luminous efficiency can be obtained from the obtained reaction product.

The specific fluorene polymer as described above can be suitably used alone as a material for forming a light emitting layer in an organic EL device.
According to this fluorene polymer, it is possible to form a light emitting layer having excellent durability as compared with the first fluorene compound described above.

  This specific fluorene polymer is usually used as a light emitting layer forming liquid by dissolving it in an appropriate organic solvent. This light emitting layer forming liquid is applied to the surface of the substrate on which the light emitting layer is to be formed, and an organic solvent is removed from the obtained coating film to form a light emitting layer in the organic EL device. .

  The organic solvent for preparing the light emitting layer forming liquid is not particularly limited as long as it can dissolve a specific fluorene polymer, and specific examples thereof include formation of a light emitting layer made of the first fluorene compound described above. What was illustrated as an organic solvent for preparing a liquid can be mentioned.

Although the usage-amount of an organic solvent changes with kinds of specific fluorene polymer, it is the quantity from which the density | concentration of a specific fluorene polymer will be 0.5-10 mass% normally.
Moreover, as means for applying the light emitting layer forming liquid, for example, a spin coating method, a dipping method, a roll coating method, an ink jet method, a printing method, or the like can be used.

  Such a specific fluorene polymer has a fluorescence emission characteristic, and has an electron transporting property from its chemical structure, a high electrical stability, and an excellent emission characteristic. Therefore, it is suitable as a material constituting the light emitting layer in the organic EL element, and according to this specific fluorene polymer, the light emitting layer in the organic EL element can be easily formed by a wet method.

<Organic EL device>
FIG. 1 is an explanatory cross-sectional view showing an example of the configuration of the organic EL element of the present invention.
In the organic EL element of this example, an anode 2 as an electrode for supplying holes is provided on a transparent substrate 1 by, for example, a transparent conductive film, and a hole injecting and transporting layer 3 is provided on the anode 2. A light emitting layer 4 is provided on the hole injecting and transporting layer 3, and a cathode 6 which is an electrode for supplying electrons is provided on the light emitting layer 4. The anode 2 and the cathode 6 are electrically connected to a DC power source 7.

In this organic EL element, as the transparent substrate 1, a glass substrate, a transparent resin substrate, a quartz glass substrate, or the like can be used.
As a material constituting the anode 2, a transparent material having a high work function, for example, 4 eV or more is preferably used. Here, the work function refers to the minimum work required to extract electrons from a solid in a vacuum. For example, an ITO (Indium Tin Oxide) film, a tin oxide (SnO ₂ ) film, a copper oxide (CuO) film, or a zinc oxide (ZnO) film can be used as the anode 2.

The hole injection transport layer 3 is provided to efficiently supply holes to the light emitting layer 4 and has a function of receiving holes from the anode 2 and transporting them to the light emitting layer 4. Is. As a material constituting the hole injecting and transporting layer 3, for example, a charge injecting and transporting material such as poly (3,4-ethylenedioxythiophene), poly (3,4-ethylenedioxythiophene) -polystyrenesulfonate is preferably used. Can be used.
The thickness of the hole injection transport layer 3 is, for example, 10 to 200 nm.

The light-emitting layer 4 has a function of combining electrons and holes and emitting the binding energy as light. The light-emitting layer 4 is composed of the first fluorene compound or the specific fluorene polymer (hereinafter referred to as the fluorene polymer). (Also referred to as “specific fluorene-based material”).
Although the thickness of the light emitting layer 4 is not specifically limited, Usually, it selects in the range of 5-200 nm.

As a material constituting the cathode 6, a material having a small work function, for example, 4 eV or less is used. As a specific example of the cathode 6, a metal film made of aluminum, calcium, magnesium, indium, or the like, or an alloy film of these metals can be used.
Although the thickness of the cathode 6 changes with kinds of material, it is 10-1000 nm normally, Preferably it is 50-200 nm.

In the present invention, the organic EL element is manufactured as follows, for example.
First, the anode 2 is formed on the transparent substrate 1.
As a method of forming the anode 2, a vacuum deposition method, a sputtering method, or the like can be used. A commercially available material in which a transparent conductive film such as an ITO film is formed on the surface of a transparent substrate such as a glass substrate can also be used.

A hole injection transport layer 3 is formed on the anode 2 thus formed.
As a method for forming the hole injection transport layer 3, specifically, a hole injection transport layer forming liquid is prepared by dissolving the charge injection transport material in an appropriate solvent. A method of forming the hole injection transport layer 3 by applying to the surface of the anode 2 and subjecting the obtained coating film to solvent removal treatment can be used.

  Next, a solution containing the specific fluorene-based material is used as a light emitting layer forming liquid, this light emitting layer forming liquid is applied onto the hole injecting and transporting layer 3, and the obtained coating film is subjected to heat treatment to thereby produce a light emitting layer. 4 is formed.

  And the organic EL element which has a structure shown in FIG. 1 is obtained by forming the cathode 6 by utilizing dry methods, such as a vacuum evaporation method, on the light emitting layer 4 formed in this way.

In the above organic EL element, when a DC voltage is applied between the anode 2 and the cathode 6 by the DC power source 7, the light emitting layer 4 emits light, and this light is emitted from the hole injection transport layer 3, the anode 2. Then, the light is emitted to the outside through the transparent substrate 1.
According to the organic EL element having such a configuration, since the light emitting layer 4 is formed of the first fluorene compound or the specific fluorene polymer, excellent light emission characteristics as well as electron transport properties can be obtained.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

[Example 1]
In Example 1, a first fluorene compound is produced.

  A solution prepared by dissolving 14.3 g (30 mmol) of the compound represented by the following formula (I) in 120 ml of tetrahydrofuran was cooled to −78 ° C., and the pentane solution 39 of t-butyllithium having a concentration of 1.5 M was added to this solution. 4 ml was gradually added dropwise, and the mixture was stirred at the same temperature for 1 hour to cause lithiation reaction to obtain a lithium fluorene compound in which the bromine atom in formula (I) was replaced with a lithium atom, and dimesityl boron was added to this system. A solution in which 19.3 g (72 mmol) of fluoride was dissolved in 50 ml of tetrahydrofuran was added dropwise, and the temperature of this reaction system was kept at room temperature and stirred for 12 hours. The obtained reaction solution was separated and washed with a saturated saline solution, the organic layer was dried over anhydrous magnesium sulfate, the organic solvent was removed by distillation under reduced pressure, and column purification treatment was carried out to obtain 16.4 g of the reaction product. Obtained.

According to LC-MS analysis, the obtained reaction product was analyzed by LC-MS. From the mass, in the general formula (1-1), m and n were both 3, and R ¹ and R ² were 2, 4, and It was confirmed that the compound was bonded to the 6-position and was a methyl group (hereinafter also referred to as “fluorene compound (1-1)”).

[Example 2]
In Example 2, a second fluorene compound is produced.

  In the solution obtained by dissolving 16.0 g (20 mmol) of the fluorene compound (1-1) obtained in Example 1 and 64 mg (0.4 mmol) of iron (III) chloride in 60 ml of chloroform, 2. After 5 ml (48 mmol) was gradually added dropwise at room temperature, the resulting reaction solution was heated to reflux and stirred for 8 hours, and then an aqueous sodium thiosulfate solution was poured into the reaction system. Separating and extracting the resulting reaction solution with chloroform, washing the extract three times with water, further drying the organic layer with anhydrous magnesium sulfate, removing the organic solvent by distillation under reduced pressure, and performing column purification treatment Gave 15.7 g of reaction product.

According to LC-MS analysis, the obtained reaction product was analyzed by mass, and in the general formula (1-2), m and n were both 3, and each of R ¹ and R ² was 2, 4 and It was confirmed that the compound was bonded to the 6-position, was a methyl group, and had a configuration in which X ¹ was a bromine atom (hereinafter also referred to as “fluorene compound (1-2)”).

Example 3
In Example 3, a fluorene polymer is produced.

0.15 g (0.15 mmol) of the fluorene compound (1-2) obtained in Example 2 and 9,9-dioctyl-2,7-bis (4,4,5,5-tetramethyl-1,3) , 2-Dioxaborolan-2-yl) fluorene 0.19 g (0.3 mmol), 9,9-bis (4-diphenylaminophenyl) -2,7-dibromofluorene 0.12 g (0.15 mmol), tetrakis By dissolving 0.01 g (0.01 mmol) of (triphenylphosphine) palladium (0) in a mixed solvent of 6 ml of toluene and ₃ ml of 2NNa ₂ CO ₃ aqueous solution, the resulting solution is heated to 110 ° C. Polymerization was performed for 25 hours. Thereafter, 0.06 g (0.5 mmol) of phenylboronic acid was added to the reaction system at the same temperature and reacted for 4 hours, and then 0.16 g (1 mmol) of bromobenzene was added and reacted for another 4 hours. The polymer ends were replaced.
The obtained reaction solution was separated and washed with 1N hydrochloric acid and diethylamine aqueous solution in this order, and the organic layer was dried over anhydrous magnesium sulfate. Then, after removing the organic solvent by distillation under reduced pressure, reprecipitation treatment with acetone is performed, so that in general formula (2), m and n are both 3, and each of R ¹ and R ² is 2, A polymer comprising a repeating unit having a structure in which it is bonded to positions 4 and 6 and is a methyl group, and R ³ and R ⁴ are both octyl groups, and a phenyl group is bonded to both ends thereof (hereinafter referred to as a polymer). Also referred to as “fluorene polymer (1).” 0.11 g was obtained.

  It was confirmed that the obtained fluorene polymer (1) had a polystyrene-reduced weight average molecular weight (Mw) of 18000 by gel permeation chromatography.

Example 4
(Example of production of organic EL element)
An organic EL device having a light emitting layer made of the fluorene compound (1-1) and having the structure shown in FIG. 1 was produced.
That is, a transparent glass substrate having a transparent conductive film made of ITO formed on the surface is prepared, and this substrate is subjected to ultrasonic using a neutral detergent, ultrapure water, isopropyl alcohol, ultrapure water and acetone in this order. Washing was performed by further irradiating ultraviolet rays in an ozone atmosphere.
A solution of poly (3,4-ethylenedioxythiophene) (PEDOT) was applied on the transparent conductive film of this substrate by a spin coating method, and then the obtained coating film with a thickness of 65 nm was 250 under a nitrogen atmosphere. A hole injecting and transporting layer was formed by drying at 30 ° C. for 30 minutes.
Next, a cyclohexanone solution (concentration 3% by mass) of the fluorene compound (1-1) was applied to the surface of the obtained hole injecting and transporting layer by a spin coating method, and the obtained coating film having a thickness of 40 nm was applied in a nitrogen atmosphere. A light emitting layer was formed by drying at 120 ° C. for 10 minutes below.
Next, in a vacuum apparatus depressurized to 1 × 10 ⁻⁴ Pa or less, a cathode is formed on the surface of the light emitting layer by depositing calcium with a thickness of 30 nm and aluminum with a thickness of 100 nm, and then sealed with a glass material. Thus, an organic EL element (hereinafter also referred to as “organic EL element (1)”) was manufactured.

  About the obtained organic EL element (1), it replaces with a fluorene compound (1-1), and the organic EL element which has a light emitting layer which consists of a polymer which consists of a repeating unit represented by a following formula (B) (Hereinafter, it is also referred to as “comparative organic EL element (1)”.) When confirmed by comparison with the light emission characteristics, it was driven at a higher current density than the comparative organic EL element (1), and the maximum The brightness was 1.2 times. This result shows that the fluorene compound (1-1) constituting the light emitting layer in the organic EL element (1) has a larger electron transporting property than the polymer constituting the light emitting layer in the comparative organic EL element (1). This is probably because a good carrier balance was obtained.

Example 5
(Example of production of organic EL element)
In the production example of the organic EL device of Example 4, organic EL was obtained by the same method as in Example 4 except that the fluorene polymer (1) was used instead of the fluorene compound (1-1) as the material of the light emitting layer. An element (hereinafter also referred to as “organic EL element (2)”) was produced.

  When the obtained organic EL element (2) was confirmed by comparing its emission characteristics with the emission characteristics of the comparative organic EL element (1), the maximum luminance was twice that of the comparative organic EL element (1). there were. This result is considered because the fluorene polymer (1) constituting the light emitting layer in the organic EL element (2) has a structure in which a hole transporting site and an electron transporting site are incorporated.

It is sectional drawing for description which shows the structure in an example of the organic electroluminescent element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Anode 3 Hole injection transport layer 4 Light emitting layer 6 Cathode 7 DC power supply

Claims (7)

A fluorene compound represented by the following general formula (1-1):

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. m is an integer of 0 to 5, and n is an integer of 0 to 5. ] The fluorene compound according to claim 1 is obtained by reacting a lithium phenylfluorene compound represented by the following formula (A) with a compound represented by the following general formula (A) in the presence of a solvent. A method for producing a fluorene compound characterized by the above.

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. m is an integer of 0 to 5, and n is an integer of 0 to 5. ] The fluorene compound represented by the following general formula (1-2).

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. X ¹ represents a halogen atom. m is an integer of 0 to 5, and n is an integer of 0 to 5. ] The fluorene compound according to claim 3 is obtained by reacting a fluorene compound represented by the following general formula (1-1) with a halogen in the presence of iron chloride and a solvent. Manufacturing method.

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. m is an integer of 0 to 5, and n is an integer of 0 to 5. ] A fluorene polymer comprising a repeating unit represented by the following general formula (2).

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. R ³ and R ⁴ each independently represents an alkyl group or an aryl group, and may be the same or different from each other. R ³ and R ⁴ may be bonded to each other to form a ring structure. Furthermore, each of the alkyl group and aryl group representing R ³ and R ⁴ may be substituted or unsubstituted. m is an integer of 0 to 5, and n is an integer of 0 to 5. ] A fluorene compound represented by the following general formula (1-2), a compound represented by the following general formula (B), and a compound represented by the following general formula (C) in the presence of a catalyst and a solvent A fluorene polymer production method according to claim 5, wherein the fluorene polymer according to claim 5 is obtained by reaction.

[Wherein, R ¹ and R ² each independently represent a monovalent organic group, and may be the same or different from each other. X ¹ represents a halogen atom. m is an integer of 0 to 5, and n is an integer of 0 to 5. ]

[Wherein, X ² represents a halogen atom. ]

[Wherein, R ³ and R ⁴ each independently represent an alkyl group or an aryl group, and may be the same or different from each other. R ³ and R ⁴ may be bonded to each other to form a ring structure. Furthermore, each of the alkyl group and aryl group representing R ³ and R ⁴ may be substituted or unsubstituted. ]   An organic electroluminescence device comprising a light emitting layer formed of the fluorene compound according to claim 1 or the fluorene polymer according to claim 5.

Images