JP2002322100A - Polyphenylene compound and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a spiro-type polyphenylene compound capable of forming an amorphous thin film capable of providing good emission efficiency, hardly being crystallized at all, and having homogeneity, and further to provide a method for producing the compound. SOLUTION: The polyphenylene compound is represented by formula (1) (wherein, R<1> , R<2> , R<3> , R<4> , R<5> , R<6> and R<7> are each independently <=10C alkyl group). The method for producing the polyphenylene compound comprises: a boron compound of pinacol is Suzuki-coupled with a tetrabromo compound by using a transition metal catalyst (e.g. palladium catalyst) to provide the polyphenylene compound represented by formula (1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyphenylene compound useful as a light emitting material for an organic electroluminescent device and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, the importance of interfaces between humans and machines, including multimedia-oriented products, has been increasing. In order for humans to operate the machine more comfortably and efficiently, it is necessary to extract information from the operated machine without error, concisely, instantly, and in a sufficient amount,
For this purpose, various display devices such as displays have been studied. Further, with the downsizing of machines, the demand for downsizing and thinning of display elements is increasing day by day.

For example, there has been remarkable progress in miniaturization of laptop information processing devices that are integrated with display elements, such as notebook personal computers and notebook word processors. There are also great innovations regarding

[0004] Today, liquid crystal displays are used as interfaces for various products, and our daily use is widely used for products such as laptop-type information processing equipment as well as small-sized televisions, watches and calculators. Have been. These liquid crystal displays have been studied as the interface between humans and machines, from small to large-capacity display devices, as the center of display elements, taking advantage of the characteristics of liquid crystal driven at low voltage and low power consumption. .

However, since this liquid crystal display is not self-luminous, it requires a backlight, and requires more power to drive the backlight than to drive the liquid crystal. Shorter,
There are restrictions on use.

Another problem is that the liquid crystal display is not suitable for a large display device such as a large display because the viewing angle is narrow. In addition, since the liquid crystal display is a display method based on the alignment state of liquid crystal molecules, it is considered that a significant problem that the contrast changes depending on the angle even within the viewing angle.

In view of the driving method, the active matrix method, which is one of the driving methods, has a response speed sufficient to handle moving images, but the TFT (thin film transistor)
Since a driving circuit is used, it is difficult to increase the screen size due to pixel defects. In liquid crystal displays, another driving method, the simple matrix method, is low in cost and relatively easy to increase the screen size, but has the problem that it does not have a sufficient response speed to handle moving images. is there.

On the other hand, as a self-luminous display element, a plasma display element, an inorganic electroluminescent element, an organic electroluminescent element and the like have been studied.

The plasma display element uses plasma emission in a low-pressure gas for display, and is suitable for increasing the size and capacity, but has problems in terms of thinning and cost. Further, it requires a high voltage AC bias for driving, and is not suitable for portable devices.

As the inorganic electroluminescent device, a green light emitting display or the like has been commercialized, but like the plasma display device, it is driven by an AC bias, and requires several hundred volts for driving, and is not practical.

However, with the development of technology, the three primary colors R (red), G (green), and B (blue) required for color display have been successfully achieved. It is difficult to control the wavelength and the like, and it seems that full color is difficult.

On the other hand, the electroluminescence phenomenon caused by an organic compound is as follows.
It has been studied for a long time since the light emission phenomenon caused by carrier injection into an anthracene single crystal that emits strong fluorescence was discovered in the early 1960's. Has been carried out as a basic study of carrier injection.

However, in 1987 Eastman Kodak T
Since ang et al. announced an organic thin-film electroluminescent device with a laminated structure having an amorphous light-emitting layer capable of low-voltage driving and high-brightness light emission, the emission, stability, and brightness of the three primary colors of R, G, and B have been observed in various directions. Research and development on ascending, laminating structures, manufacturing methods, and the like have been actively conducted.

Further, various novel materials have been invented by molecular design, which is a characteristic of organic materials, and are applied to color displays of organic electroluminescent element displays having excellent characteristics such as DC low-voltage driving and self-luminous properties. Research is starting to take off.

[0015]

However, considering the practical use of the organic electroluminescent device, there is still a problem in the reliability of the device such as chromaticity, luminous life and luminous efficiency. Clearing the problem is a major factor in realizing the practical application of a full-color display using an organic light-emitting device.

In order to improve the life of the organic electroluminescent device,
It is important to improve the amorphous property of the organic electroluminescent device material. In particular, with respect to the organic electroluminescent blue device, there are very few organic electroluminescent device materials that can achieve high luminous efficiency and high color purity and have a high amorphous property.

When an organic electroluminescent element is used as a blue element, as an organic material capable of realizing high luminous efficiency and high color purity, a polyphenylene compound having a spiro structure described in JP-A-7-27853 and the like can be used. Useful.
Among them, the spiro-type polyphenylene compound represented by the following structural formula (1) is a material that can realize high efficiency and high color purity when it is used as a light emitting material of an organic electroluminescent device. Has a problem that although the glass transition point is high (literature value: 212 ° C.), it is easy to be crystallized, and the crystallinity may contribute to the element deterioration.

[0018]

Embedded image Structural formula (1):

Therefore, it is considered that maintaining the emission characteristics of the spiro-type polyphenylene compound and producing a compound with higher amorphousness leads to an improvement in the life of the organic electroluminescent blue device.

An object of the present invention is to provide good luminous efficiency,
An object of the present invention is to provide a spiro-type polyphenylene compound which is extremely difficult to crystallize and forms a uniform amorphous thin film, and a method for producing the same.

[0021]

That is, the present invention relates to a polyphenylene compound represented by the following general formula (1).

Embedded image General formula (1): (However, in the general formula (1), R ¹ , R ² , R ³ ,
R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a carbon atom of 1
It may be an alkyl group such as 0 or less such as a methyl group, an ethyl group, and a propyl group (hereinafter the same). )).

Further, the present invention provides a Suzuki compound comprising a pinacol boron compound represented by the following general formula (2) and a tetrabromo compound represented by the following general formula (3) using a transition metal catalyst (for example, a palladium catalyst). The present invention also provides a method for producing a polyphenylene compound by obtaining a polyphenylene compound represented by the following general formula (1) by coupling.

Embedded image General formula (2):

Embedded image General formula (3):

Embedded image General formula (1): (However, in the general formulas (1), (2) and (3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently a carbon atom having 10 or less. It may be an alkyl group.)

According to the present invention, the spiro-type polyphenylene compound represented by the above structural formula (1) has four terminal phenyl groups having substituents (p
-Cyclohexyl group), it is possible to realize a full-color display such as a color display and to extend the life of the device.

The polyphenylene compound emits stable blue light and is highly useful as a luminescent material.

Such a polyphenylene compound is synthesized by a Suzuki coupling reaction, gives good luminous efficiency, and is generally and efficiently used for an organic electroluminescent device for forming a uniform amorphous thin film. Can be manufactured.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

When the polyphenylene compound of the present invention is used as a blue light emitting material for an organic electroluminescent device, it forms a film having high luminous efficiency, high color purity, excellent thermal stability, and high amorphousness by vapor deposition. can do.

The compound of the present invention is preferably a substituted polyphenylene compound represented by the following structural formula (2).

Embedded image Structural formula (2):

The process for producing the compound of the present invention is specified, for example, by the following reaction formulas (1) to (5) (T
f is a trifluoromethanesulfonic acid group).

Embedded image Reaction formula (1):

Embedded image Reaction formula (2):

Embedded image Reaction formula (3):

Embedded image Reaction formula (4):

Embedded image Reaction formula (5):

FIGS. 14 to 17 show examples of organic electroluminescent devices (EL devices) using the polyphenylene compound according to the present invention as an organic light emitting material.

FIG. 14 shows a transmissive organic electroluminescent element A in which emitted light 20 passes through the cathode 3, and the emitted light 20 can be observed from the protective layer 4 side. FIG. 13 shows a reflective organic electroluminescent element B in which light reflected by the cathode 3 is also obtained as emission light 20.

In the figure, reference numeral 1 denotes a substrate for forming an organic electroluminescent device, which can be made of glass, plastic or other appropriate material. In addition, when the organic electroluminescent element is used in combination with another display element, the substrate can be shared. For example, when active matrix driving is performed, a TFT (Thin Film Transistors) can be used as the substrate. It is possible.
Reference numeral 2 denotes a transparent electrode (anode). For example, in the above-mentioned transmission type organic electroluminescent device A, a transparent electrode ITO (Indium tin oxidizer) is used.
e), IZO (Indium zinc oxide), SnO _{2 and the} like can be used. In the reflection type organic electroluminescent device B, Cr, Fe,
Co, Ni, Cu, Ta, W, Pt, Mo, Au and alloys thereof can be used.

Reference numeral 5 denotes an organic light emitting layer, which contains a polyphenylene compound according to the present invention as a light emitting material. With respect to this light-emitting layer, conventionally known various structures can be used as a layer structure for obtaining the organic electroluminescence 20. As will be described later, for example, when a material constituting either the hole transport layer or the electron transport layer has a light emitting property, a structure in which these thin films are laminated can be used. In order to further enhance the charge transport performance, one or both of the hole transport layer and the electron transport layer has a structure in which thin films of a plurality of types of materials are stacked,
Alternatively, use of a thin film having a composition in which a plurality of types of materials are mixed is not prevented. Further, in order to enhance the luminous efficiency,
Using at least one or more kinds of fluorescent material, the sandwich structure between the thin hole transport layer and an electron transporting layer, further a hole transporting layer at least one kind of fluorescent material or the electron transport layer Alternatively, a structure included in both of them may be used. In these cases, a thin film for controlling the transport of holes or electrons can be included in the layer structure in order to improve the luminous efficiency.

The polyphenylene compound according to the present invention comprises
Since it has both electron transporting performance and hole transporting performance, it can be used as a light emitting layer also serving as an electron transporting layer or as a light emitting layer also serving as a hole transporting layer in the device configuration. Further, it is also possible to adopt a configuration in which the polyphenylene compound purified by the method for purifying a polyphenylene compound according to the present invention is sandwiched between an electron transporting layer and a hole transporting layer as a light emitting layer.

In FIGS. 14 and 15, reference numeral 3 denotes a cathode. As an electrode material, an alloy of an active metal such as Li, Mg, Ca and the like and a metal such as Ag, Al, In, LiF, Li
O ₂ or a structure in which these are laminated can be used. In a transmission type organic electroluminescent device, by adjusting the thickness of the cathode, a light transmittance suitable for the intended use can be obtained. On the other hand, in a reflection type organic electroluminescent device, the thickness of the cathode is reduced to maintain a high transmittance, and the anode is made of a material having a high reflectance, so that the organic electroluminescence is taken out to the cathode side. Can be. Further, reference numeral 4 in the drawing denotes a sealing / protecting layer, and its effect is improved by adopting a structure that covers the entire organic electroluminescent element. If airtightness is maintained, an appropriate material can be used. Reference numeral 8 denotes a drive power supply for current injection.

In the organic electroluminescent device to which the polyphenylene compound according to the present invention is applied, the organic layer has an organic laminated structure in which a hole transport layer and an electron transport layer are laminated (single hetero structure). As the material for forming the hole transport layer or the electron transport layer, the polyphenylene compound according to the present invention may be used. Alternatively, the organic layer has an organic laminated structure (double hetero structure) in which a hole transport layer, a light-emitting layer, and an electron transport layer are sequentially laminated, and the material for forming the light-emitting layer is based on the present invention. Polyphenylene compounds may be used.

FIG. 16 shows an example of an organic electroluminescent device having such an organic laminated structure. FIG. 16 shows a transparent substrate 1, a light-transmitting anode 2, a hole transport layer 6, and an electron transport layer. The organic electroluminescent device C has a single-hetero structure, which has a laminated structure in which an organic layer 5a composed of a cathode 7 and a cathode 3 are sequentially laminated, and the laminated structure is sealed with a protective film 4.

In the case of a layer configuration in which the light emitting layer is omitted as shown in FIG. 16, emitted light 20 of a predetermined wavelength is generated from the interface between the hole transport layer 6 and the electron transport layer 7. These emitted lights are observed from the substrate 1 side.

FIG. 17 shows a light-transmitting anode 2, an organic layer 5 b composed of a hole transport layer 10, a light-emitting layer 11 and an electron transport layer 12, and a cathode 3 on a light-transmitting substrate 1. Are sequentially laminated, and this laminated structure is sealed with a protective film 4 to form an organic electroluminescent device D having a double hetero structure.

In the organic electroluminescent device shown in FIG. 17, when a DC voltage is applied between the anode 2 and the cathode 3, the holes injected from the anode 2 pass through the hole transport layer 10, and The electrons injected from 3 reach the light emitting layer 11 via the electron transport layer 12 respectively. As a result, electron / hole recombination occurs in the light emitting layer 11 to generate singlet excitons, and the singlet excitons emit light of a predetermined wavelength.

In each of the organic electroluminescent elements C and D described above, the substrate 1 can be made of a light-transmissive material such as glass or plastic. In addition, in the case of using in combination with another display element, or in the case of arranging the stacked structures illustrated in FIGS. 16 and 17 in a matrix,
This substrate may be shared. In addition, each of the elements C and D can have either a transmission type or a reflection type structure.

The anode 2 is a transparent electrode and is made of ITO.
(Indium tin oxide), SnO ₂ or the like can be used. A thin film made of an organic substance or an organometallic compound may be provided between the anode 2 and the hole transport layer 6 (or the hole transport layer 10) for the purpose of improving the charge injection efficiency. When the protective film 4 is formed of a conductive material such as a metal,
An insulating film may be provided on the side surface of the anode 2.

The organic layer 5a in the organic electroluminescent device C is an organic layer in which a hole transport layer 6 and an electron transport layer 7 are laminated, and one or both of them are formed with a polyphenylene compound according to the present invention. It may be contained to form the luminescent hole transport layer 6 or the electron transport layer 7. Organic electroluminescent device D
Is an organic layer in which a hole transport layer 10, a light-emitting layer 11 containing a polyphenylene compound according to the present invention, and an electron transport layer 12 are laminated.
Various laminated structures can be adopted. For example, one or both of the hole transport layer and the electron transport layer may have a light emitting property.

It is particularly preferable that the hole transport layer 6, the electron transport layer 7, and the light emitting layer 11 are layers made of the polyphenylene compound according to the present invention.
It may be formed only from the polyphenylene compound according to the present invention, or may be formed by co-evaporation of the polyphenylene compound according to the present invention and another hole or electron transporting material (eg, aromatic amines and pyrazolines). May be. Further, in the hole transport layer, a hole transport layer in which a plurality of types of hole transport materials are stacked may be formed in order to improve hole transport performance.

In the organic electroluminescent device C, the light emitting layer may be the electron transporting light emitting layer 7, but depending on the voltage applied from the power supply 8, the light emitting layer may emit light at the hole transporting layer 6 or its interface. There is. Similarly, in the organic electroluminescent device D, the light emitting layer may be the electron transport layer 12 or the hole transport layer 10 other than the layer 11. In order to improve the light emitting performance, it is preferable that the light emitting layer 11 using at least one kind of fluorescent material is sandwiched between the hole transport layer and the electron transport layer. Alternatively, a structure in which this fluorescent material is contained in the hole transporting layer or the electron transporting layer, or both of them may be configured. In such a case, in order to improve the luminous efficiency, a thin film (such as a hole blocking layer or an exciton generation layer) for controlling the transport of holes or electrons can be included in the layer configuration.

The material used for the cathode 3 is L
An alloy of an active metal such as i, Mg, Ca or the like and a metal such as Ag, Al, In or the like can be used, and a structure in which these metal layers are laminated may be used. Incidentally, by appropriately selecting the thickness and material of the cathode, an organic electroluminescent device suitable for the intended use can be produced.

The protective film 4 functions as a sealing film, and the charge injection efficiency and the luminous efficiency can be improved by adopting a structure that covers the entire organic electroluminescent element. As long as the airtightness is maintained, the material can be appropriately selected, such as a single metal such as aluminum, gold, and chromium, or an alloy.

The current applied to each of the above-mentioned organic electroluminescent elements is usually a direct current, but a pulse current or an alternating current may be used. The current value and the voltage value are not particularly limited as long as they are within a range not passing through the element. However, in consideration of power consumption and life of the organic electroluminescent element, it is desirable to emit light efficiently with as little electric energy as possible.

Next, FIG. 18 shows an example of the structure of a flat display using an organic electroluminescent device to which the polyphenylene compound according to the present invention is applied. As shown in the figure, for example, in the case of a full-color display, an organic layer 5 (5a, 5b) capable of emitting three primary colors of red (R), green (G) and blue (B)
Is disposed between the cathode 3 and the anode 2. The cathode 3 and the anode 2 can be provided in a stripe shape crossing each other, and are selected by the luminance signal circuit 14 and the control circuit 15 with a built-in shift register, and a signal voltage is applied to each of them. The organic layer at a position (pixel) where the anode 3 and the anode 2 intersect is configured to emit light. As this driving method, a simple matrix system or an active matrix system can be used.

FIG. 18 shows a simple matrix of 8 × 3 RGB, for example, in which a laminate 5 comprising a hole transporting layer and at least one of a light emitting layer and an electron transporting layer is placed between the cathode 3 and the anode 2. This is arranged (see FIGS. 16 and 17). The cathode and the anode are both patterned in a stripe shape, are made to go perpendicular to each other in a matrix form, and apply a signal voltage in a time series by the control circuits 15 and 14 having a built-in shift register, and emit light at the crossing position. It is a thing. The EL element having such a configuration can be used not only as a display for characters and signals, but also as an image reproducing device. Further, it is possible to configure a multi-color or full-color all-solid-state flat panel display by arranging stripe patterns of the cathode 3 and the anode 2 for each color of red (R), green (G), and blue (B). Become.

[0051]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples.

Embodiment 1

Embedded image Reaction formula (1):

4-cyclohexylphenol (10.0
g, 56.7 mmol) in 100 ml of pyridine was cooled sufficiently in an ice bath. 19.2 g (68.0 mmol) of trifluoromethanesulfonic acid was added dropwise little by little.
Stir for 4 hours while cooling in an ice bath.
Tracked in C. The reaction solution was further reacted at room temperature for 1 hour. After completion of the reaction, pyridine was removed under reduced pressure, and the product was extracted twice with chloroform / water. Organic layer is saturated NaC
Washed with an aqueous solution and dried over anhydrous Na ₂ SO ₄ .

Column chromatography using hexane as a developing solvent (silica gel: WAKO C-300)
And purified as a colorless liquid compound (1) (16.5 g, 9
1%). Identification of this compound, ¹ H-NMR: was performed by (solvent heavy chloroform, see FIG. 1) Measurement ^[1
H-NMR: δ 1.15 to 1.5 (5H), 2.65 to 2.95 (5H), 2.45
~ 2.65 (1H), 7.11 ~ 7.21 (2H), 7.22 ~ 7.42 (2H) pp
m].

[0055]

Embedded image Reaction formula (2):

Compound (1) (3.50 g, 11.4 mm
ol), 4-methoxyphenylboronic acid (2.40 g,
15.8 mmol), tetrakis (triphenylphosphine) palladium (0) (550 mg), toluene 10
0 ml, 50 ml of ₂ mol / l K ₂ CO ₃ aqueous solution
The mixture was heated and stirred at 0 ° C. under a nitrogen atmosphere for 8 hours. The progress of the reaction was monitored by TLC. After completion of the reaction, the reaction solution was extracted with toluene / water, washed with a saturated aqueous solution of NaCl, and dried over anhydrous Na ₂ SO ₄ .

The toluene solution was passed through activated alumina # 200, and then concentrated under reduced pressure. The obtained crystals were recrystallized twice with ethanol to obtain compound (2) (2.2 g, 70%). The compound was identified by ¹ H-NMR (solvent: deuterated chloroform, see FIG. 2) measurement [ ¹ H-NMR:
δ 1.25 to 1.55 (5H), 1.7 to 2.0 (5H), 2.45 to 2.65 (1
H), 3.70-3.85 (s, 3H), 6.9-7.05 (d, 2H), 7.15-
7.35 (d, 2H), 7.4-7.6 (m, 4H) ppm].

[0058]

Embedded image Reaction formula (3):

Compound (2) (2.80 g, 10.6 mm
ol) was dissolved in 100 ml of chloroform and cooled sufficiently in an ice bath under a nitrogen atmosphere. Boron tribromide (3.
(17 g, 12.7 mmol) was slowly added dropwise and stirred. After stirring for 2 hours, the reaction solution was returned to room temperature, and T
The reaction was followed by LC. The reaction was so slow that additional boron tribromide (3.17 g, 12.7 mm
ol) and stirred at room temperature for 24 hours. After completion of the reaction, ice was added to the reaction solution, and extracted with chloroform / water.

Washing with saturated aqueous NaCl solution, anhydrous Na ₂ S
After drying over O ₄ and removing the solvent under reduced pressure, recrystallization was performed with ethanol to give compound (3) (2.52 g, 92%).
Was obtained as colorless crystals. The identity of this compound was determined by ¹ H-N
[ ¹ H-NMR: δ 1.25 to 1.55 (5H), 1.7 to 2.0 (5H), MR (solvent: deuterated chloroform, see FIG. 3) measurement
2.45 to 2.65 (1H), 4.65 to 4.8 (-OH, 1H), 6.75 to 6.9 (d,
2H), 7.15 to 7.30 (d, 2H), 7.35 to 7.55 (m, 4H) ppm].

[0061]

[Image Omitted] Reaction formula (4):

Compound (3) (3.50 g, 13.9 mm)
ol) in 100 ml of pyridine was cooled sufficiently in an ice bath. Then, trifluoromethanesulfonic acid (4.4)
2 g, 16.7 mmol) were added dropwise in small portions. The mixture was stirred for 4 hours while cooling in an ice bath, and the progress of the reaction was monitored by TLC. The reaction solution was further reacted at room temperature for 1 hour. After completion of the reaction, pyridine was removed under reduced pressure, and the product was extracted twice with chloroform / water. The organic layer was washed with a saturated aqueous solution of NaCl and dried over anhydrous Na ₂ SO ₄ .

Using toluene / hexane as a developing solvent,
Column chromatography (silica gel: WAKO C
-300) to give Compound (4) (4.20 g, 8
0%) as colorless crystals. The identification of this compound is ¹
H-NMR (solvent: deuterated chloroform, see FIG. 4) [ ¹ H-NMR: δ 1.25 to 1.55 (5H), 1.7 to
2.0 (5H), 2.45 to 2.65 (1H), 7.25 to 7.4 (m, 4H), 7.
45 to 7.55 (d, 2H), 7.56 to 7.75 (d, 2H) ppm].

[0064]

Embedded image Reaction formula (5):

Compound (4) (5.00 g, 13.1 mm)
ol), bis (pinacolato) diboron (3.98 g,
15.7 mmol), 1,1′-bis (diphenylphosphino) ferrocene palladium (II) chloride (Pd
Cl ₂ (dppf), 344 mg, 3 mol%), 1,
1'-bis (diphenylphosphino) ferrocene (dp
pf, 260 mg, 3 mol%), potassium acetate 4.6
1 g (47.0 mmol) and 200 ml of dioxane in 9
The mixture was heated to 0 ° C. and stirred for 8 hours under a nitrogen atmosphere. The progress of the reaction was confirmed by TLC.

After completion of the reaction, extraction was performed with chloroform / water,
After washing with a saturated aqueous NaCl solution and drying over anhydrous Na ₂ SO ₄ , column chromatography (silica gel: WAKO C-300) using THF / hexane as a developing solvent.
And then recrystallized from ethanol to give compound (5)
(3.60 g, 76%) as colorless needles. This compound was identified by ¹ H-NMR (solvent: deuterated chloroform, see FIG. 5) [ ¹ H-NMR: δ1.2
~ 1.55 (27H), 1.7 ~ 2.0 (5H), 2.45 ~ 2.65 (1H),
7.2 to 7.4 (d, 2H), 7.45 to 7.7 (m, 4H), 7.8 to 7.95 (d, 2H)
ppm].

[0067]

Embedded image Reaction formula (6):

2,2 ', 7,7'-tetrabromo-9,
9'-spirofluorene (1.10 g, 1.77 mmol
l), compound (5) (3.00 g, 8.31 mmol)
And PdCl ₂ (dppf) (300 mg, 4 mol
%) Was dissolved in 45 ml of THF, and the mixture was stirred at room temperature for 30 minutes under a nitrogen atmosphere. Thereafter, 20 ml of a saturated aqueous solution of NaHCO ₃ purged with nitrogen (30 min) was added, and the mixture was refluxed for 8 hours. The progress of the reaction was monitored by ¹ H-NMR and TLC.

After the completion of the reaction, the reaction mixture was filtered. The product was extracted with chloroform / water, and the chloroform layer was washed with brine and dried over anhydrous sodium sulfate. After passing through alumina # 300, the mixture was concentrated under reduced pressure to obtain colorless crystals.
The product was recrystallized from chloroform several times, then recrystallized from toluene and chloroform again, and purified to obtain a colorless white crystal of compound (6) (42%). The compound was identified by ¹ H-NMR (solvent: deuterated chloroform, see FIG. 6). [ ¹ H-NMR: δ 1.25 to 1.55
(40H), 1.7-2.0 (40H), 2.45-2.65 (4H), 7.05-
7.15 (s, 4H), 7.16 to 7.36 (m, 8H), 7.42 to 7.62 (m, 24
H), 7.65-7.75 (d, 2H), 7.9-8.05 (d, 2H) ppm].

The results of the visible / ultraviolet absorption spectrum and fluorescence measurement of the target compound (6) in a THF solution are shown in FIGS. 7 and 8, respectively (the maximum visible absorption wavelength: 338 nm,
(Fluorescence peak wavelength: 378 nm, 396 nm). The peak of this fluorescence spectrum is shifted to a shorter wavelength side than the known polyphenylene compound of the structural formula (1) shown in FIG. FIG. 10 shows a visible / ultraviolet absorption spectrum and a fluorescence spectrum of the thin film of the target compound (6).

Example 2 In this example, a thermal analysis of the substituted polyphenylene compound represented by the compound (6) synthesized in Example 1 was performed by a differential scanning calorimeter (DSC). FIG.
Shown in The thermal analysis was performed using a DSC manufactured by PerkinElmer.
(Pyrist DSC) was used. DS of substituted polyphenylene compound represented by compound (6) synthesized in Example 1 using aluminum oxide (Al ₂ O ₃ ) as a reference
C measurement was performed. The measurement conditions were the same for the sample and the reference weight of 3.5 mg, and the measurement was performed using an aluminum closed container (manufactured by PerkinElmer).

Measurement conditions 1) 30 ° C. → 440 ° C. (heating rate: 10 ° C./min) 2) Maintain at 440 ° C. for 1 minute 3) 440 ° C. → 30 ° C. (cooling rate: 100 ° C./min) 4) 30 ° C. 5min maintenance 5) 30 ℃ → 440 ℃ (heating rate: 10 ℃ / min)

COMPARATIVE EXAMPLE 1 In this comparative example, aluminum oxide (Al ₂ O ₃ ) was used as a reference, and a spiro-type polyphenylene compound represented by the aforementioned structural formula (1) was used as a measurement sample.
C measurement was performed, and the results are shown in FIG. The measurement conditions were the same as those described in Example 2 above.

Table 1 shows the results of Example 2 and Comparative Example 1.

[0075]

[Table 1] Table 1

From Table 1, it was found that the conventional polyphenylene compound represented by the structural formula (1) did not have a glass transition point but a crystallization point (347 ° C.). On the other hand, the substituted polyphenylene compound of the present invention represented by the compound (6) has a glass transition point of 236 ° C. and a crystallization point of 277 ° C.
Was observed. From this, the substituted polyphenylene compound represented by the compound (6) exhibited thermophysical properties rich in amorphousness as compared with the conventional polyphenylene compound.

[0077] EXAMPLE 3 This example uses the compound obtained as described above polyphenylene (6) as an electron transport layer (and the light-emitting layer), an organic double-hetero structure as shown in FIG. 17 This is an example in which an electroluminescent element is manufactured.

Specifically, on a glass substrate, the following layers 1 to 3 were sequentially formed in respective film thicknesses, and an organic electroluminescent device serving as a blue light emitting device was manufactured. At this time, first, the anode material is formed by sputtering, and then the anode material is 2 mm × 2 m
An insulating film (silicon oxide film) having an opening window exposed in the range of m was formed on the substrate. Next, from the hole injection layer material to the buffer layer material was formed on the anode material by vacuum deposition from above the deposition mask. Thereafter, the deposition mask was removed, and a cathode material was laminated on the buffer layer material in a vacuum state.

Anode: ITO: 190 nm, hole injection layer: 2-TNATA [4,4 ', 4 "-tris (2-naphthylphenylamino) triphenylamine] ... 20 nm, hole transport layer: Triphenylamine tetramer represented by 3): 50 nm; light-emitting layer: polyphenylene of compound (6) synthesized as in Example 1; 30 nm; electron transport layer: represented by the following structural formula (4) Alq ₃ ...
10 nm, buffer layer: lithium oxide ... 0.5 nm, cathode: aluminum ... 200 nm.

[0080]

Embedded image Structural formula (3):

Embedded image Structural formula (4): Alq ₃

When the characteristics of the organic electroluminescent device thus manufactured were measured, the emission color was blue, and as a result of spectral measurement, the emission spectrum shown in FIG. 13 was obtained. Further, when the current density is 25 mA / cm ² , the luminance is 151 c.
d / m ² , and it was confirmed that sufficient luminance was obtained. The spectroscopic measurement was performed using a spectral radiance meter (Minolta CS-10).
00).

[0082]

According to the present invention, as described above,
Since a substituent (p-cyclohexyl group) is introduced into a polyphenylene compound that has a high fluorescence quantum yield and can achieve high color purity, it has a molecular structure with improved amorphousness. Therefore, when the compound of the present invention is used as a light-emitting material of an organic electroluminescent device, a light-emitting layer having a high amorphous property can be formed, so that the life of the device can be extended. The compound of the present invention can be efficiently produced by using a Suzuki coupling reaction using a palladium catalyst. Also,
This polyphenylene compound emits stable blue light and is highly useful as a luminescent material.

[Brief description of the drawings]

FIG. 1 is a diagram showing an NMR spectrum of a synthetic intermediate of a polyphenylene compound according to an example of the present invention.

FIG. 2 is a view showing an NMR spectrum of another synthetic intermediate.

FIG. 3 is a diagram showing an NMR spectrum of another synthetic intermediate.

FIG. 4 is a view showing an NMR spectrum of another synthetic intermediate.

FIG. 5 is a diagram showing an NMR spectrum of still another synthetic intermediate.

FIG. 6 is a diagram showing an NMR spectrum of the polyphenylene compound.

FIG. 7 is a graph showing the polyphenylene compound visible in the TFT.
FIG. 3 is an ultraviolet absorption spectrum diagram.

FIG. 8 is a fluorescence spectrum diagram of a polyphenylene compound in a TFT.

FIG. 9 is a diagram showing a visible / ultraviolet absorption and fluorescence spectrum of a comparative polyphenylene compound in a TFT.

FIG. 10 is a view showing a visible / ultraviolet absorption spectrum of a polyphenylene compound thin film according to an example of the present invention.

FIG. 11 is a DSC measurement characteristic diagram of a polyphenylene compound according to an example of the present invention.

FIG. 12 is a DSC diagram of a polyphenylene compound according to a comparative example.
It is a measurement characteristic diagram.

FIG. 13 is a fluorescence spectrum diagram when the polyphenylene compound according to the present invention is used in an organic electroluminescent device.

FIG. 14 is a schematic cross-sectional view of a main part when a polyphenylene compound according to the present invention is used in an organic electroluminescent device.

FIG. 15 is a schematic view showing a main part when a polyphenylene compound according to the present invention is used in another organic electroluminescent device.

FIG. 16 is a schematic cross-sectional view of main parts when a polyphenylene compound according to the present invention is used in another organic electroluminescent device.

FIG. 17 is a schematic cross-sectional view of a principal part when a polyphenylene compound according to the present invention is used in still another organic electroluminescent device.

FIG. 18 is a configuration diagram of a full-color flat display using an organic electroluminescent element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Transparent electrode (anode), 3 ... Cathode, 4 ... Protective film, 5 5a, 5b ... Organic layer, 6 ... Hole transport layer, 7 ... Electron transport layer, 8 ... Power supply, 10 ... Positive Hole transporting layer, 11 light emitting layer, 12 electron transporting layer, 14 luminance signal circuit, 15 control circuit, 20 light emission, A, B, C, D organic electroluminescent element

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/22 H05B 33/22 BD (72) Inventor Tetsuro Shibanuma 6-7 Kita Shinagawa, Shinagawa-ku, Tokyo No. 35 Inside Sony Corporation (72) Inventor Kazunori Takada 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo F-term inside Sony Corporation (reference) 3K007 AB04 AB11 CA01 CB01 DA01 DB03 EB00 4H006 AA01 AA02 AC24 4J032 CA03 CB01 CC01 CE24 CG03

Claims (2)

[Claims] 1. A polyphenylene compound represented by the following general formula (1). Embedded image General formula (1): (However, in the general formula (1), R ¹ , R ² , R ³ ,
R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a carbon atom of 1
The alkyl group may be 0 or less. A) a polyphenylene compound represented by the formula: 2. A compound represented by the following general formula (2) by coupling a pinacol boron compound represented by the following general formula (2) with a tetrabromo compound represented by the following general formula (3) using a transition metal catalyst. A method for producing a polyphenylene compound, which obtains the polyphenylene compound represented by 1). Embedded image General formula (2): Embedded image General formula (3): Embedded image General formula (1): (However, in the general formulas (1), (2) and (3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^6, and R ⁷ are each independently a group having 10 or less carbon atoms. It may be an alkyl group.)