JP5227510B2 - Pyrazine derivatives, and light-emitting elements, display devices, and electronic devices using the pyrazine derivatives - Google Patents

Description

  The present invention relates to a pyrazine derivative. Further, the present invention relates to a light-emitting element including the pyrazine derivative. Further, the present invention relates to a display device including a light-emitting element including the pyrazine derivative.

  In recent years, a light-emitting element using a light-emitting compound has features of low power consumption, light weight, and thinness, and is regarded as a promising next-generation display (display device). Further, since it is a self-luminous type, it is said that there is no problem of viewing angle and the like, and it is excellent in visibility as compared with a liquid crystal display (LCD).

  The basic structure of a light-emitting element is a structure having a light-emitting layer containing a light-emitting compound between a pair of electrodes. In such a light-emitting element, when a voltage is applied, holes injected from the anode and electrons injected from the cathode recombine at the emission center in the light-emitting layer to excite the molecules, and the excited molecules become the basis. It is said that light is emitted by releasing energy when returning to the state. Note that excited states generated by recombination include a singlet excited state and a triplet excited state. Emission is considered to be possible in either excited state, especially emission when returning from the singlet excited state directly to the ground state is fluorescence, and emission when returning from the triplet excited state to the ground state is phosphorescence. Is defined.

  It is thought that the singlet excited state and the triplet excited state, which are excited states, are statistically generated at 1: 3. Therefore, when phosphorescence, which is light emission when returning from the triplet excited state to the ground state, is used, theoretically, a light emitting device having an internal quantum efficiency (ratio of photons generated with respect to injected carriers) of 75% to 100%. It is thought that can be obtained. That is, if phosphorescence can be used, the luminous efficiency can be significantly improved as compared with the case of using fluorescence.

  However, phosphorescence of general organic compounds could not be observed at room temperature. This is because the ground state of an organic compound is usually a singlet ground state, and a transition from a triplet excited state to a singlet ground state is a forbidden transition. On the other hand, since the transition from the singlet excited state to the singlet ground state is an allowable transition, fluorescence can be observed. However, in recent years, as disclosed in Patent Document 1, a compound capable of emitting phosphorescence, that is, a compound capable of converting light upon returning from a triplet excited state to a ground state (hereinafter referred to as a phosphorescent compound) has been discovered. Research is also actively conducted (see, for example, Patent Document 1).

  Even in the case where a light-emitting element is manufactured using a phosphorescent compound, the phosphorescent compound is used in a state of being dispersed in a host material in order to prevent a decrease in light emission efficiency due to concentration quenching. Therefore, in order to efficiently obtain light emission from the phosphorescent compound, it is important to select a host material.

In order to obtain light emission efficiently from a phosphorescent compound, it has been found that a host material having a bipolar property is suitable. However, most organic compounds are monopolar materials that are biased toward hole transporting or electron transporting. Therefore, development of a bipolar material having both hole transporting properties and electron transporting properties has been demanded.
Japanese Patent Laid-Open No. 2005-170851

  In view of the above, an object of the present invention is to provide a novel material having bipolar properties, a light-emitting element including the novel material, and a display device including the light-emitting element.

  Another object of the present invention is to provide a novel bipolar material that can be used as a host material in which a light-emitting compound is dispersed. In particular, an object of the present invention is to provide a novel bipolar material that can be used as a host material in which a phosphorescent compound is dispersed.

  Another object of the present invention is to provide a novel bipolar material that can be used as a light-emitting compound.

  The present invention is a pyrazine derivative represented by the following general formula (g-1).

In the general formula (g-1), R ¹ , R ² , and R ³ in the formula may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. It represents one of the following aryl groups. A in the formula represents any of the substituents represented by general formula (a-1), general formula (a-2), general formula (a-3), or general formula (a-4). . R ⁴ in the formula represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. R ⁵ , R ⁶ and R ⁷ may be the same or different, and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ may be the same or different, each represents an aryl group having 6 to 25 carbon atoms, and α is 6 or more carbon atoms Represents an arylene group of 25 or less. The aryl group may have a substituent or may be unsubstituted. The arylene group may have a substituent or may be unsubstituted.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-2).

In the general formula (g-2), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. Represents any of aryl groups. A in the formula represents any of the substituents represented by general formula (a-1), general formula (a-2), general formula (a-3), or general formula (a-4). . R ⁴ in the formula represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. R ⁵ , R ⁶ and R ⁷ may be the same or different, and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ may be the same or different, each represents an aryl group having 6 to 25 carbon atoms, and α is carbon Represents an arylene group of 6 or more and 25 or less. The aryl group may have a substituent or may be unsubstituted. The arylene group may have a substituent or may be unsubstituted.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-3).

In the general formula (g-3), R ¹ , R ² and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 or more carbon atoms. Represents any of 25 or less aryl groups. The aryl group may have a substituent or may be unsubstituted. Ar ¹ and Ar ² may be the same as or different from each other, and are phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, and 9,9-dimethyl. It represents either a fluoren-2-yl group or a spiro-9,9′-bifluoren-2-yl group.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-4).

In the general formula (g-4), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 or more carbon atoms. Represents any of 25 or less aryl groups. Ar ³ , Ar ⁴ , and Ar ⁵ may be the same or different and each represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-5).

In the general formula (g-5), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 or more carbon atoms. Represents any of 25 or less aryl groups. Ar ³ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

In the general formula (g-5), Ar ³ in the formula is phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9- It is preferably either a dimethylfluoren-2-yl group or a spiro-9,9′-bifluoren-2-yl group.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-6).

In the general formula (g-6), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 or more carbon atoms. Represents any of 25 or less aryl groups. R ⁴ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. Ar ⁶ is a phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9-dimethylfluoren-2-yl group, or spiro-9,9. Represents one of '-bifluoren-2-yl groups. The aryl group may have a substituent or may be unsubstituted.

  Further, the present invention is a pyrazine derivative represented by the following general formula (g-7).

In the general formula (g-7), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 or more carbon atoms. Represents any of 25 or less aryl groups. R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ⁷ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-8).

In the general formula (g-8), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 or more carbon atoms. Represents any of 25 or less aryl groups. R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ⁷ represents an aryl group. The aryl group may have a substituent or may be unsubstituted.

In the general formula (g-8), Ar ⁷ in the formula is phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9- It is preferably either a dimethylfluoren-2-yl group or a spiro-9,9′-bifluoren-2-yl group.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-9).

In the general formula (g-9), R ¹ and R ² in the formula may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl having 6 to 25 carbon atoms. Represents any of the groups. Ar ¹ and Ar ² may be the same or different, and phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9-dimethylfluorene- It represents either a 2-yl group or a spiro-9,9′-bifluoren-2-yl group. The aryl group may have a substituent or may be unsubstituted.

  Further, the present invention is a pyrazine derivative represented by the following general formula (g-10).

In the general formula (g-10), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl having 6 to 25 carbon atoms. Represents any of the groups. Ar ³ , Ar ⁴ and Ar ⁵ may be the same or different and each represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-11).

In the general formula (g-11), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl having 6 to 25 carbon atoms. Represents any of the groups. Ar ³ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

In the general formula (g-11), Ar ³ in the formula is a phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9- It is preferably either a dimethylfluoren-2-yl group or a spiro-9,9′-bifluoren-2-yl group.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-12).

In the general formula (g-12), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl having 6 to 25 carbon atoms. Represents any of the groups. R ⁴ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. Ar ⁶ is a phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9-dimethylfluoren-2-yl group, or spiro-9,9 ′. -Represents any of bifluoren-2-yl groups. The aryl group may have a substituent or may be unsubstituted.

  Moreover, this invention is a pyrazine derivative represented by the following general formula (g-13).

In the general formula (g-13), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl having 6 to 25 carbon atoms. Represents any of the groups. R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ⁷ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

  Further, the present invention is a pyrazine derivative represented by the following general formula (g-14).

In the general formula (g-14), R ¹ and R ² in the formula may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl having 6 to 25 carbon atoms. Represents any of the groups. R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ⁷ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

In the general formula (g-14), Ar ⁷ in the formula is phenyl, 1-naphthyl, 2-naphthyl, 2-biphenyl, 3-biphenyl, 4-biphenyl, 9,9- It is preferably either a dimethylfluoren-2-yl group or a spiro-9,9′-bifluoren-2-yl group.

  The present invention is a light-emitting element having a layer containing a pyrazine derivative according to any one of the general formulas (g-1) to (g-14) between a pair of electrodes.

  The present invention is a light-emitting element having a layer containing the pyrazine derivative according to any one of the general formulas (g-1) to (g-14) and a light-emitting compound between a pair of electrodes. is there.

  The present invention is a light-emitting element having a layer containing the pyrazine derivative according to any one of the general formulas (g-1) to (g-14) and a phosphorescent compound between a pair of electrodes. is there. Note that a phosphorescent compound refers to a compound that can emit phosphorescence, that is, a compound that can convert light emitted when returning from a triplet excited state to a ground state into luminescence.

  In addition, the present invention is a display device including a light-emitting element including the pyrazine derivative according to any one of the general formulas (g-1) to (g-14).

  Further, the present invention is a display device including a light-emitting element including the pyrazine derivative according to any one of the general formulas (g-1) to (g-14) and a phosphorescent compound.

  The present invention is an electronic device having a light-emitting element including the pyrazine derivative according to any one of the general formulas (g-1) to (g-14).

  The present invention is an electronic device having a light-emitting element including the pyrazine derivative according to any one of the general formulas (g-1) to (g-14) and a phosphorescent compound.

  The pyrazine derivative of the present invention is a pyrazine derivative having bipolar properties and excellent in both electron transport properties and hole transport properties.

  The pyrazine derivative of the present invention is a pyrazine derivative that is stable against electrochemical oxidation and reduction.

  Furthermore, the pyrazine derivative of the present invention is a light-emitting compound having bipolar properties and excellent in both electron transport properties and hole transport properties.

  Further, by dispersing the phosphorescent compound in the layer formed of the pyrazine derivative of the present invention, a light emitting element with extremely high light emission efficiency can be obtained.

(Embodiment 1)
In this embodiment mode, a pyrazine derivative of the present invention will be described.

  The pyrazine derivative of the present invention is represented by the following general formula (g-1).

In the general formula (g-1), R ¹ , R ² , and R ³ in the formula may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. It represents one of the following aryl groups. A in the formula represents any of the substituents represented by general formula (a-1), general formula (a-2), general formula (a-3), or general formula (a-4). . R ⁴ in the formula represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. R ⁵ , R ⁶ and R ⁷ may be the same or different, and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ^{1 to} Ar ⁷ may be the same or different and each represents an aryl group having 6 to 25 carbon atoms, and α represents an arylene group having 6 to 25 carbon atoms. In addition, the aryl group in a formula may have a substituent and may be unsubstituted. Similarly, the arylene group may have a substituent or may be unsubstituted.

  In the general formula (g-1), specific examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, i-propyl group, n-propyl group, n-butyl group, t- A butyl group, an i-butyl group, an s-butyl group, or the like can be given. Specific examples of the aryl group having 6 to 25 carbon atoms include phenyl, o-tolyl, m-tolyl, p-tolyl, naphthyl, 2-naphthyl, 4-biphenyl, 3- Biphenyl group, 2-biphenyl group, 9,9-methylfluoren-2-yl group, spiro-9,9′-bifluoren-2-yl group and the like can be mentioned. Furthermore, specific examples of the arylene group having 6 to 25 carbon atoms include o-phenylene group, m-phenylene group, p-phenylene group, 1,5-naphthylene group, 1,4-naphthylene group, 9,9- Examples thereof include a dimethylfluorene-2,7-diyl group, a 4,4-biphenylene group, and a spiro-9,9′-bifluorene-2,7-diyl group.

In the general formula (g-1), the present invention is such that A in the formula is a substituent represented by the general formula (a-1), Ar ¹ and Ar ² are a phenyl group, and a 1-naphthyl group. , 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9-dimethylfluoren-2-yl group, or spiro-9,9′-bifluoren-2-yl group It is preferable that the synthesis is easy. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-3).

In the general formula (g-3), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a carbon number. It represents any of 6 to 25 aryl groups. The aryl group may have a substituent or may be unsubstituted.

  In the general formula (g-1), the present invention provides a larger triplet excitation when A in the formula is a substituent represented by the general formula (a-4) and α is a phenylene group. It is preferable because energy can be obtained and chemical stability can be obtained. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-4).

In the general formula (g-4), R ¹ , R ² , and R ³ in the formula may be the same or different, and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a carbon number. It represents any of 6 to 25 aryl groups. Ar ³ , Ar ⁴ , and Ar ⁵ may be the same or different and each represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

In the general formula (g-1), A is a substituent represented by the general formula (a-2), Ar ⁴ and Ar ⁵ are phenyl groups, and α is 1 A 4-phenylene group is preferred because a larger triplet excitation energy can be obtained, and synthesis is facilitated. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-5).

In the general formula (g-5), R ¹ , R ² and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a carbon number. It represents any of 6 to 25 aryl groups. Ar ³ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

Furthermore, the present invention relates to the above general formula (g-5), wherein Ar ³ is a phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, A 9,9-dimethylfluoren-2-yl group or a spiro-9,9′-bifluoren-2-yl group is preferred because it facilitates synthesis.

In the general formula (g-1), A is a substituent represented by the general formula (a-3), Ar ⁶ is a phenyl group, a 1-naphthyl group, 2- A naphthyl group, a 2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a 9,9-dimethylfluoren-2-yl group, or a spiro-9,9′-bifluoren-2-yl group The synthesis is easy and preferable. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-6).

In the general formula (g-6), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a carbon number. It represents any of 6 to 25 aryl groups. R ⁴ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

  In the general formula (g-1), the present invention provides a larger triplet excitation when A in the formula is a substituent represented by the general formula (a-4) and α is a phenylene group. It is preferable because energy can be obtained and chemical stability can be obtained. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-7).

In the general formula (g-7), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a carbon number. It represents any of 6 to 25 aryl groups. R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ⁷ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

  In the general formula (g-1), the present invention is such that A in the formula is a substituent represented by the general formula (a-4), and α is a 1,4-phenylene group. It is preferable because large triplet excitation energy can be obtained and chemical stability can be obtained. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-8).

In the general formula (g-8), R ¹ , R ² , and R ³ in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a carbon number. It represents any of 6 to 25 aryl groups. R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ⁷ represents an aryl group. The aryl group may have a substituent or may be unsubstituted.

In the general formula (g-8), Ar ⁷ in the formula is a phenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9 , 9-dimethylfluoren-2-yl group or spiro-9,9′-bifluoren-2-yl group is preferable because of easy synthesis.

  Moreover, the pyrazine derivative of the present invention is represented by the following general formula (g-2).

In the general formula (g-2), R ¹ and R ² in the formula may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl having 6 to 25 carbon atoms. Represents any of the groups. The aryl group may have a substituent or may be unsubstituted. A in the formula represents any of the substituents represented by general formula (a-1), general formula (a-2), general formula (a-3), or general formula (a-4). . R ⁴ in the formula represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. R ⁵ , R ⁶ and R ⁷ may be the same or different, and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted. Ar ^{1 to} Ar ⁷ in the formula may be the same or different and each represents an aryl group having 6 to 25 carbon atoms, and α represents an arylene group having 6 to 25 carbon atoms. The arylene group may have a substituent or may be unsubstituted.

  In the general formula (g-2), specific examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, i-propyl group, n-propyl group, n-butyl group, t- A butyl group, an i-butyl group, an s-butyl group, or the like can be given. Specific examples of the aryl group having 6 to 25 carbon atoms include phenyl, o-tolyl, m-tolyl, p-tolyl, naphthyl, 2-naphthyl, 4-biphenyl, 3- Biphenyl group, 2-biphenyl group, 9,9-methylfluoren-2-yl group, spiro-9,9′-bifluoren-2-yl group and the like can be mentioned. Furthermore, specific examples of the arylene group having 6 to 25 carbon atoms include o-phenylene group, m-phenylene group, p-phenylene group, 1,5-naphthylene group, 1,4-naphthylene group, 9,9- Examples thereof include a dimethylfluorene-2,7-diyl group, a 4,4-biphenylene group, and a spiro-9,9′-bifluorene-2,7-diyl group.

In the general formula (g-2), the present invention is such that A in the formula is a substituent represented by the general formula (a-1), Ar ¹ and Ar ² are a phenyl group, and a 1-naphthyl group. , 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9-dimethylfluoren-2-yl group, spiro-9,9′-bifluoren-2-yl group When it exists, it becomes easy to synthesize and is preferable. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-9).

In the general formula (g-9), R ¹ and R ² in the formula may be the same or different, and each is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. It represents one of the following aryl groups. The aryl group may have a substituent or may be unsubstituted.

  In the general formula (g-2), the present invention provides a larger triplet excitation when A in the formula is a substituent represented by the general formula (a-2) and α is a phenylene group. It is preferable because energy can be obtained and chemical stability can be obtained. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-10).

In the general formula (g-10), R ¹ and R ² in the formula may be the same or different, and each is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. It represents one of the following aryl groups. Ar ³ , Ar ⁴ , and Ar ⁵ may be the same or different and each represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

In the general formula (g-2), A is a substituent represented by the general formula (a-2), Ar ⁴ and Ar ⁵ are phenyl groups, and α is 1 A 4-phenylene group is preferred because a larger triplet excitation energy can be obtained, and synthesis is facilitated. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-11).

In the general formula (g-11), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. It represents one of the following aryl groups. Ar ³ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

Furthermore, the present invention is the above general formula (g-11), wherein Ar ³ in the formula is a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, A 9,9-dimethylfluoren-2-yl group or a spiro-9,9′-bifluoren-2-yl group is preferred because it facilitates synthesis.

In the general formula (g-2), A is a substituent represented by the general formula (a-3), Ar ⁶ is a phenyl group, a 1-naphthyl group, 2- A naphthyl group, a 2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a 9,9-dimethylfluoren-2-yl group, or a spiro-9,9′-bifluoren-2-yl group The synthesis is easy and preferable. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-12).

In the general formula (g-12), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. It represents one of the following aryl groups. R ⁴ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

  In the general formula (g-2), the present invention provides a larger triplet excitation when A in the formula is a substituent represented by the general formula (a-4) and α is a phenylene group. It is preferable because energy can be obtained and chemical stability can be obtained. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-13).

In the general formula (g-13), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. It represents one of the following aryl groups. R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ⁷ represents an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted.

  Further, in the general formula (g-2), the present invention is such that A in the formula is a substituent represented by the general formula (a-4), and α is a 1,4-phenylene group. It is preferable because large triplet excitation energy can be obtained and chemical stability can be obtained. That is, the present invention is preferably a pyrazine derivative represented by the following general formula (g-14).

In the general formula (g-14), R ¹ and R ² in the formula may be the same or different from each other, and are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 6 to 25 carbon atoms. It represents one of the following aryl groups. R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Ar ⁷ represents an aryl group. The aryl group may have a substituent or may be unsubstituted.

In the general formula (g-14), Ar ⁷ represents a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, 9 , 9-dimethylfluoren-2-yl group or spiro-9,9′-bifluoren-2-yl group is preferable because of easy synthesis.

  Specific examples of the pyrazine derivative of the present invention include pyrazine derivatives represented by structural formulas (s-1) to (s-115). The pyrazine derivative of the present invention is not limited to the following structural formula, and may have a structure different from the structure represented by the following structural formula.

  As a synthesis method of the pyrazine derivative of the present invention, various reactions can be applied. For example, it can manufacture by performing the synthetic reaction shown to the following synthetic scheme (c-1), synthetic scheme (c-2), synthetic scheme (c-3), and synthetic scheme (c-4).

In the synthesis schemes (c-1) to (c-4), x in the formula represents a halogen atom. R ¹ , R ² and R ³ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted. R ⁴ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. R ⁵ , R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted. Ar ^{1 to} Ar ⁷ may be the same or different and each represents an aryl group having 6 to 25 carbon atoms, and α represents an arylene group having 6 to 25 carbon atoms. The arylene group may have a substituent or may be unsubstituted.

  In the above synthesis scheme (c-1), by subjecting a pyrazine derivative halide to a coupling reaction of 1 equivalent of a secondary amine compound with a palladium catalyst or monovalent copper in the presence of a base, Inventive pyrazine derivatives can be synthesized. In addition, as a base, organic bases, such as inorganic bases, such as potassium carbonate and sodium carbonate, a metal alkoxide, etc. can be used. As the palladium catalyst, palladium acetate, palladium (II) chloride, bis (dibenzylideneacetone) palladium (0), or the like can be used.

  In addition, in the synthesis scheme (c-2), the synthesis scheme (c-3), and the synthesis scheme (c-4), they can be synthesized in the same manner as the synthesis scheme (c-1) described above. That is, in each of the synthesis schemes (c-2) to (c-4), in the presence of a base, 1 equivalent of a secondary amine compound is used with a palladium catalyst or monovalent copper with respect to a pyrazine derivative halide. By performing a coupling reaction, the pyrazine derivative of the present invention can be synthesized. As the base, an inorganic base such as potassium carbonate or sodium carbonate, an organic base such as metal alkoxide, or the like can be used. As the palladium catalyst, palladium acetate, palladium (II) chloride, bis (dibenzylideneacetone) palladium (0), or the like can be used.

  In addition, the pyrazine derivative of the present invention performs, for example, the synthetic reaction shown in the following synthetic scheme (d-1), synthetic scheme (d-2), synthetic scheme (d-3), and synthetic scheme (d-4). Can be manufactured.

In the synthesis schemes (d-1) to (d-4), x in the formula represents a halogen atom. Further, R ¹ and R ² may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted. R ⁴ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 25 carbon atoms. R ⁵ , R ⁶ and R ⁷ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. The aryl group may have a substituent or may be unsubstituted. Ar ^{1 to} Ar ⁷ may be the same or different and each represents an aryl group having 6 to 25 carbon atoms, and α represents an arylene group having 6 to 25 carbon atoms.

  In the above synthesis scheme (d-1), by subjecting a pyrazine derivative halide to a coupling reaction using 2 equivalents of a secondary amine compound with a palladium catalyst or monovalent copper in the presence of a base, Inventive pyrazine derivatives can be synthesized. In addition, as a base, organic bases, such as inorganic bases, such as potassium carbonate and sodium carbonate, a metal alkoxide, etc. can be used. As the palladium catalyst, palladium acetate, palladium (II) chloride, bis (dibenzylideneacetone) palladium (0), or the like can be used.

  In addition, in the synthesis scheme (d-2) to the synthesis scheme (d-4), they can be synthesized in the same manner as the synthesis scheme (d-1) described above. That is, in each of the synthesis schemes (d-2) to (d-4), with respect to the pyrazine derivative halide, in the presence of a base, 2 equivalents of a secondary amine compound is used with a palladium catalyst or monovalent copper. By performing a coupling reaction, the pyrazine derivative of the present invention can be synthesized. In addition, as a base, organic bases, such as inorganic bases, such as potassium carbonate and sodium carbonate, a metal alkoxide, etc. can be used. As the palladium catalyst, palladium acetate, palladium (II) chloride, bis (dibenzylideneacetone) palladium (0), or the like can be used.

  The method for synthesizing the pyrazine derivative of the present invention is not limited to the method described above, and may be synthesized by other synthesis methods.

  The pyrazine derivative of the present invention synthesized as described above is a pyrazine derivative having bipolar properties and excellent in both electron transport properties and hole transport properties.

  The pyrazine derivative of the present invention is a pyrazine derivative that is stable against electrochemical oxidation and reduction.

(Embodiment 2)
In this embodiment, one embodiment of a light-emitting element using the pyrazine derivative of the present invention will be described with reference to FIGS.

  In the structure of the light-emitting element in this embodiment, a light-emitting layer is provided between a pair of electrodes (anode and cathode). In the light-emitting element of the present invention, a layer made of a substance having a high hole-injecting or electron-injecting property or a substance having a high hole-transporting or electron-transporting property is provided between each electrode and the light-emitting layer. To do. With such a structure, in the light emitting element of the present invention, a light emitting region is formed at a distance from the electrode.

  In the light-emitting element 100 illustrated in FIG. 1, a light-emitting layer 104 is provided between a first electrode 101 and a second electrode 107. In this embodiment mode, the light-emitting layer 104 includes the pyrazine derivative of the present invention and a phosphorescent compound.

  In addition, the light-emitting element 100 of the present invention has a structure in which the hole injection layer 102 and the hole transport layer 103 are sequentially stacked between the first electrode 101 and the light-emitting layer 104. Furthermore, the light-emitting element of the present invention has a structure in which an electron-transport layer 105 and an electron-injection layer 106 are sequentially stacked between the light-emitting layer 104 and the second electrode 107. Note that the element structure is not limited to this, and a known structure may be appropriately selected according to the purpose.

  In the light-emitting element 100 of the present invention, either the first electrode 101 or the second electrode 107 serves as an anode, and the other serves as a cathode. The anode refers to an electrode that injects holes into the light emitting layer, and the cathode refers to an electrode that injects electrons into the light emitting layer. In this embodiment mode, the first electrode 101 is an anode and the second electrode 107 is a cathode. Hereinafter, the light emitting device 100 of the present invention will be specifically described.

  As the first electrode 101 (anode), it is preferable to use a metal, an alloy, a conductive compound, a mixture thereof, or the like having a high work function (specifically, 4.0 eV or more). Specifically, a transparent conductive film formed using a light-transmitting conductive material may be used. For example, indium tin oxide (ITO), indium tin oxide added with silicon oxide (ITSO), indium zinc oxide (IZO), or the like can be used. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), zinc (Zn), tin (Sn), indium (In), molybdenum (Mo), iron (Fe ), Cobalt (Co), copper (Cu), palladium (Pd), or other metal materials may be used. Further, a nitride of a metal material (eg, titanium nitride (TiN)) may be used. Note that the first electrode 101 may be formed using a single layer or a stack of two or more of these materials by a method such as a sputtering method or an evaporation method. The first electrode 101 may be formed by applying a sol-gel method or the like.

As the hole injection layer 102, molybdenum oxide (MoO _x ), vanadium oxide (VO _x ), ruthenium oxide (RuO _x ), tungsten oxide (WO _x ), manganese oxide (MnO _x ), or the like is used. be able to. In addition, phthalocyanine compounds such as phthalocyanine (H ₂ Pc) and copper phthalocyanine (CuPc), or polymers such as poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) (PEDOT / PSS) may be used. Good.

For the hole-injecting layer 102, a composite material formed by combining an organic compound and an inorganic compound can also be used. The inorganic compound included in the composite material may be any substance that exhibits an electron accepting property with respect to an organic compound, and specifically, an oxide of a transition metal is preferably used. For example, titanium oxide (TiO _x ), vanadium oxide (VO _x ), molybdenum oxide (MoO _x ), tungsten oxide (WO _x ), rhenium oxide (ReO _x ), ruthenium oxide (RuO _x ), Such as chromium oxide (CrO _x ), zirconium oxide (ZrO _x ), hafnium oxide (HfO _x ), tantalum oxide (TaO _x ), silver oxide (AgO _x ), or manganese oxide (MnO _x ) Metal oxides can be used. Further, as the organic compound, it is preferable to use a material excellent in hole transportability. Specifically, an aromatic amine organic compound or a carbazole organic compound can be used. Aromatic hydrocarbon organic compounds may also be used. In this manner, a composite material including an organic compound and an inorganic compound that exhibits an electron accepting property with respect to the organic compound transfers electrons between the organic compound and the inorganic compound, thereby increasing the carrier density. Excellent hole injecting and hole transporting properties. In addition, by using a composite material including such an organic compound and an inorganic compound that exhibits an electron accepting property with respect to the organic compound as the hole injecting layer 102, the first electrode 101 and the hole injecting layer 102 have an ohmic resistance. Sexual contact is possible. As a result, a material for forming the first electrode 101 can be selected regardless of the work function.

  By providing the hole injection layer 102 in contact with the first electrode 101 as in the present invention, the hole injection barrier can be reduced. As a result, the driving voltage of the light emitting element 100 can be reduced.

As the hole-transport layer 103, a substance having a high hole-transport property can be used. Specifically, it is preferable to use an aromatic amine-based compound (that is, a compound having a benzene ring-nitrogen bond). For example, 4,4′-bis [N- (3-methylphenyl) -N-phenylamino] biphenyl and its derivative 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (Hereinafter referred to as NPB), 4,4 ′, 4 ″ -tris (N, N-diphenyl-amino) triphenylamine, 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) A starburst aromatic amine compound such as —N-phenylamino] triphenylamine can be used. Note that the substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or more. However, the present invention is not limited to this, and other substances may be used as long as they have a property of transporting more holes than electrons. Note that the hole-transporting layer 103 may be a single layer, a mixed layer, or a stack of two or more layers of these substances.

  As the light-emitting layer 104, a layer containing the pyrazine derivative of the present invention and a light-emitting compound as represented by any of the above general formulas (g-1) to (g-14) is used. Specifically, a light emitting compound is dispersed in a layer made of the pyrazine derivative of the present invention. That is, the pyrazine derivative of the present invention is used as a host material, and the luminescent compound is used as a guest material. By setting it as such a structure, light emission from the luminescent compound which is a guest material can be obtained, and the luminescent color resulting from a luminescent compound can be obtained. In addition, since the pyrazine derivative of the present invention also functions as a light emitting substance, it is possible to obtain a light emission color that is a mixture of the light emission color caused by the light emitting compound and the light emission color caused by the pyrazine derivative of the present invention.

  As the light-emitting compound included in the light-emitting layer 104, a fluorescent compound and a phosphorescent compound can be used. Specifically, as the fluorescent compound, 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (abbreviation: DCM1), 4- (dicyanomethylene) -2-methyl- 6- (julolidin-4-yl-vinyl) -4H-pyran (abbreviation: DCM2), N, N-dimethylquinacridone (abbreviation: DMQd), 9,10-diphenylanthracene (abbreviation: DPA), 5,12-diphenyl Tetracene (abbreviation: DPT), coumarin 6, perylene, rubrene, or the like can be used.

As the phosphorescent compound, bis (2-phenylbenzothiazolate-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (bt) ₂ (acac)), tris (2-phenylquino) Linato-N, C ² ′) iridium (III) (abbreviation: Ir (pq) ₃ ), bis (2-phenylquinolinato-N, C ² ′) iridium (III) acetylacetonate (abbreviation: Ir (pq) ₂ (acac)), bis [2- (2′-benzo [4,5-α] thienyl) pyridinato-N, C ^{3 ′} ] iridium (III) acetylacetonate (abbreviation: Ir (btp) ₂ (acac) ), Bis (1-phenylisoquinolinato-N, C ² ′) iridium (III) acetylacetonate (abbreviation: Ir (piq) ₂ (acac)), (acetylacetonato ) Bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (abbreviation: Ir (Fdpq) ₂ (acac)), 2,3,7,8,12,13,17,18-octaethyl A metal complex centering on a transition metal such as iridium (Ir) such as -21H, 23H-porphyrin platinum (II) (abbreviation: PtOEP) or platinum (Pt) can be used.

As the electron-transport layer 105, a substance having a high electron-transport property can be used. For example, tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [h] -quinolinato) beryllium (abbreviation: A metal complex having a quinoline skeleton or a benzoquinoline skeleton, such as BeBq ₂ ) or bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), can be used. In addition, bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) -benzothiazolate] zinc (abbreviation: Zn (BTZ)) Metal complexes having an oxazole-based or thiazole-based ligand such as ₂ ) can also be used. In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5 -(P-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5 (4-Biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2 , 4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), and the like may be used. Note that the substances described here are mainly substances having an electron mobility of 10 ⁻⁶ cm ² / Vs or more. However, the present invention is not limited to this, and other substances may be used as long as they have a property of transporting more electrons than holes. Note that the electron-transporting layer 105 may be a single layer, a mixed layer, or a stack of two or more layers of these substances.

As the electron injection layer 106, a compound of an alkali metal or an alkaline earth metal such as lithium fluoride (LiF), cesium fluoride (CsF), or calcium fluoride (CaF ₂ ) can be used. In addition, a layer made of a substance having an electron transporting property containing an alkali metal, an alkaline earth metal, an alkali metal compound, or an alkaline earth metal compound may be used. For example, a material in which lithium oxide (LiO _x ), magnesium oxide (MgO _x ), magnesium (Mg), or lithium (Li) is contained in Alq ₃ can be used. By providing the electron injection layer 106 in contact with the second electrode 107 as in the present invention, the electron injection barrier can be reduced. As a result, the driving voltage of the light emitting element 100 can be reduced.

  As the second electrode 107 (cathode), a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a low work function (specifically, 3.8 eV or less) can be used. Specifically, elements belonging to Group 1 or Group 2 of the Periodic Table of Elements, that is, alkali metals such as lithium (Li) and cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), etc. An alkaline earth metal, an alloy containing these (MgAg, AlLi), a rare earth metal such as europium (Eu), ytterbium (Yb), an alloy containing these, or the like may be used. Note that by providing the electron injection layer 106 in contact with the second electrode 107 between the second electrode 107 and the light-emitting layer 104, Al, Ag, ITO, ITSO, or the like regardless of the work function. Various conductive materials can be used for the second electrode 107.

  Note that the hole injection layer 102, the hole transport layer 103, the light emitting layer 104, the electron transport layer 105, and the electron injection layer 106 may be formed by vapor deposition. In addition, a method such as an inkjet method or a spin coating method may be used. Moreover, you may form using the different film-forming method for each electrode or each layer.

  In the light-emitting element 100 of the present invention having the above structure, current flows due to a potential difference generated between the first electrode 101 and the second electrode 107, and holes and electrons are recombined in the light-emitting layer 104. And emits light.

  Note that light emission of the light-emitting element 100 of the present invention can be extracted from one direction or both directions by selecting materials of the first electrode 101 and the second electrode 107. For example, light emission can be extracted from the first electrode 101 side by making the first electrode 101 light-transmitting and the second electrode 107 light-shielding (reflective). Alternatively, light emission can be extracted from the second electrode 107 side by making the first electrode 101 light-shielding (reflective) and the second electrode 107 light-transmissive. Further, by making both the first electrode 101 and the second electrode 107 light-transmitting, light emission can be extracted from both electrode sides.

  The light-emitting element of this embodiment is not limited to the above as long as the light-emitting layer 104 is provided between at least the first electrode 101 and the second electrode 107. Therefore, it may be changed as appropriate according to the purpose.

  Although the first electrode 101 is an anode in this embodiment mode, the present invention is not limited to this and may be a cathode. In the case where the first electrode 101 is a cathode, an electron injection layer, an electron transport layer, a light emitting layer, a hole transport layer, a hole injection layer, and a second electrode 107 serving as an anode are sequentially stacked in contact with the cathode. The structure may be made. Also in this case, other than the structure in which the light emitting layer is provided between the first electrode 101 and the second electrode 107, it can be changed as appropriate according to the purpose.

  The light-emitting element 100 of the present invention uses the pyrazine derivative of the present invention having a bipolar property as a host material. As a result, light emission from the light-emitting compound that is the guest material can be efficiently obtained. In particular, light emission can be efficiently obtained when a phosphorescent compound is used as the guest material.

(Embodiment 3)
In this embodiment, a light-emitting element having a structure different from that described in Embodiment 2 will be described. In addition, since it is the same structure as Embodiment 2 except a light emitting layer, description is abbreviate | omitted.

  In the light-emitting element 200 of the present invention illustrated in FIG. 2, the light-emitting layer 204 is provided between the first electrode 101 and the second electrode 107 as in the light-emitting element described in Embodiment Mode 1. Note that the structure of the element is not limited to that illustrated in FIGS. 2A and 2B, and includes at least a pair of electrodes (a first electrode 101 and a second electrode 107) and a light-emitting layer provided between the pair of electrodes. What is necessary is just to select a well-known structure suitably for another structure according to the objective.

  In the light-emitting element 200 of this embodiment, a layer containing only the pyrazine derivative of the present invention represented by any of the above general formulas (g-1) to (g-14) is used as the light-emitting layer 204. The pyrazine derivative of the present invention can obtain a blue to green emission color and can be suitably used as a light-emitting compound in a light-emitting element.

  Further, the pyrazine derivative of the present invention may be dispersed as a guest material in a host material. As a host material for dispersing the pyrazine derivative of the present invention, a host material having a larger energy gap than the pyrazine derivative of the present invention may be used. Specifically, 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), or the like is used. Can do.

  As described above, the pyrazine derivative of the present invention has bipolar properties and functions as a luminescent compound. Therefore, it can be used as a material for the light-emitting layer 204 without containing other light-emitting compounds.

  In addition, since the pyrazine derivative of the present invention has bipolar properties, the light emitting region is not easily biased to the interface of the stacked films. Therefore, a light-emitting element having favorable characteristics with little change in emission spectrum caused by interaction such as exciplex and a decrease in emission efficiency can be obtained.

(Embodiment 4)
In this embodiment, an example of a display device of the present invention will be described with a manufacturing method with reference to FIGS. Note that in this embodiment, an example of an active matrix display device in which a pixel portion 370 and a driver circuit portion 380 are formed over the same substrate is described.

  First, the base insulating film 301 is formed over the substrate 300. In the case where light emission is extracted using the substrate 300 side as a display surface, a light-transmitting glass substrate or quartz substrate may be used as the substrate 300. Alternatively, a light-transmitting plastic substrate having heat resistance that can withstand the processing temperature during the process may be used. In addition, in the case where light emission is extracted using a surface opposite to the substrate 300 side as a display surface, in addition to the above-described substrate, a silicon substrate, a metal substrate, or a stainless substrate on which an insulating film is formed may be used. A substrate that can withstand at least heat generated during the process may be used. In this embodiment, a glass substrate is used as the substrate 300. The refractive index of the glass substrate is around 1.55.

  As the base insulating film 301, an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is used, and is formed of a single layer or two or more layers by means of a sputtering method, an LPCVD method, a plasma CVD method, or the like. To do. In addition, if the unevenness of the substrate and the diffusion of impurities from the substrate are not a problem, the base insulating film is not necessarily formed.

  Next, a semiconductor layer is formed over the base insulating film 301. The semiconductor layer is formed by forming an amorphous semiconductor film by sputtering, LPCVD, plasma CVD, or the like, and then laser crystallization, thermal crystallization, or thermal crystallization using a catalytic element such as nickel. Is crystallized using the above to obtain a crystalline semiconductor film. In the case of using a thermal crystallization method using a catalyst element such as nickel, it is preferable to remove the catalyst element by gettering after crystallization. Thereafter, a crystalline semiconductor film is formed into a desired shape by photolithography.

  Next, a gate insulating film 302 is formed to cover the semiconductor layer. As the gate insulating film 302, an insulating film containing silicon is formed by a plasma CVD method or a sputtering method. Alternatively, a single layer or a stacked structure of an insulating film containing silicon may be formed and then surface nitridation using microwave plasma may be performed.

  Next, a gate electrode is formed over the gate insulating film 302. The gate electrode is a conductive material such as a refractory metal such as tungsten (W), chromium (Cr), tantalum (Ta), tantalum nitride (TaN), or molybdenum (Mo), or an alloy or compound containing a refractory metal as a main component. What is necessary is just to form by methods, such as a sputtering method and a vapor deposition method, using material. Further, the gate electrode may have a single layer structure of these conductive materials, or may have two or more layers.

  Next, an impurity is added in order to form an impurity region having n-type or p-type conductivity in the semiconductor layer of each of the transistors 310, 330, and 340 formed in the pixel portion 370 and the driver circuit portion 380. The impurity to be added may be selected as appropriate in accordance with each transistor.

  Next, first interlayer insulating films 303a, 303b, and 303c are formed. As the first interlayer insulating films 303a, 303b, and 303c, an inorganic insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film, an organic resin film, or a film containing siloxane can be used. May be formed of a single layer or two or more layers. Siloxane is a material in which a skeleton structure is formed by a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group having 1 to 4 carbon atoms or an aromatic hydrocarbon) is used. Further, a fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as a substituent. Further, when an inorganic insulating film is formed, a sputtering method, an LPCVD method, a plasma CVD method, or the like is used. When an organic resin film or a film containing siloxane is formed, a coating method may be used. Although the three-layer structure of the first interlayer insulating films 303a, 303b, and 303c is used here, the interlayer insulating film may be a single layer or a plurality of layers.

  Next, the first interlayer insulating films 303a, 303b, and 303c are selectively etched to form contact holes that reach the semiconductor layers. Then, a source electrode and a drain electrode reaching the semiconductor layer through the contact holes are formed. The source electrode and the drain electrode are formed by laminating a metal film by a sputtering method and then selectively etching the metal laminate film by a photolithography method.

  Through the above steps, the transistor 310 connected to the light-emitting element, the capacitor 311, the transistor 330 and the transistor 340 arranged in the driver circuit portion are formed. In this embodiment, the transistor 310 connected to the light-emitting element for off-state current reduction has a multi-gate structure (a semiconductor layer including two or more channel formation regions connected in series and each channel formation region). And a structure having two or more gate electrodes to which an electric field is applied. Note that the present invention is not limited to this, and a single gate structure such as the transistor 330 or the transistor 340 may be employed. Further, although the transistor 330 and the transistor 340 arranged in the driver circuit portion have a single gate structure, the present invention is not limited to this and may have a multi-gate structure.

  The transistor 310, the transistor 330, and the transistor 340 each have a structure having a low concentration impurity region (LDD region) that overlaps with the gate electrode with the gate insulating film 302 interposed therebetween. Note that the present invention is not limited to this, and a structure without an LDD region may be employed.

  The pixel portion 370 is also provided with a transistor 320 that functions as a switching element as illustrated in FIG. The transistor 320 has a structure having a low-concentration impurity region (LDD region) that does not overlap with the gate electrode with the gate insulating film 302 interposed therebetween. Note that the present invention is not limited to this, and a structure without an LDD region may be employed.

  In the driver circuit portion 380, the transistor 330 can be an n-channel transistor, the transistor 340 can be a p-channel transistor, and the transistor 330 and the transistor 340 can be complementarily connected to form a CMOS circuit. With such a configuration, various types of circuits can be realized.

  Next, a second interlayer insulating film 304 is formed over the first interlayer insulating films 303a, 303b, and 303c. The second interlayer insulating film 304 can be formed using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film. Alternatively, an organic resin film such as acrylic or polyimide, or a film containing siloxane may be used. These insulating films may be formed as a single layer or two or more layers. Siloxane is a material in which a skeleton structure is formed by a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group having 1 to 4 carbon atoms or an aromatic hydrocarbon) is used. Further, a fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as a substituent. When an inorganic insulating film is formed, a sputtering method, an LPCVD method, a plasma CVD method, or the like is used. When an organic resin film or a film containing siloxane is formed, a coating method may be used. Although the second interlayer insulating film 304 is a single layer here, it may be a plurality of layers. Note that in the case where an organic resin film, a film containing siloxane, or the like is used as the second interlayer insulating film 304, a stacked structure of an inorganic insulating film such as a silicon oxide film or a silicon nitride film is preferable.

  Next, the light-emitting element 350 is formed. First, a first electrode 351 (an anode or a cathode of an organic light emitting element) is formed. The first electrode 351 is electrically connected to the first transistor 310 through the second interlayer insulating film 304. Note that the first electrode 351 may be formed in a manner similar to that in Embodiments 2 and 3, and description thereof is omitted.

  Next, a partition layer 305 that covers an end portion of the first electrode 351 is formed. The partition layer 305 may be formed by forming an insulating film such as acrylic, siloxane, resist, silicon oxide, or polyimide by a coating method and forming the obtained insulating film into a desired shape by a photolithography method.

  Next, a layer 352 and a second electrode 353 (a cathode or an anode of a light-emitting element) are sequentially formed. Note that the layer 352 is formed using the pyrazine derivative of the present invention represented by any one of the general formula (g-1) to the general formula (g-14) as described in Embodiment 2 or Embodiment 3. Contains layers. The layer 352 includes at least a light-emitting layer, and may include a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and the like. The layer 352 and the second electrode 353 may be formed in a manner similar to that in Embodiments 2 and 3, and description thereof is omitted.

  Through the above process, the light-emitting element 350 including the first electrode 351, the layer 352, and the second electrode 353 is formed. Note that the light-emitting element 350 is separated from another light-emitting element provided adjacent thereto by a partition layer 305.

Next, the light-emitting element 350 is sealed by bonding the sealing substrate 360 with the sealant 306. That is, in the display device, the outer periphery of the display region is surrounded by the sealant 306 and sealed with the pair of substrates 300 and 360. Note that in this embodiment mode, the sealant 306 is provided so as to hang over the drive circuit portion 380. However, it may be provided so as to surround at least the outer periphery of the display region. Further, the space 307 surrounded by the sealing material 306 may be filled with a filler or may be filled with a dry inert gas.

  Finally, the FPC 393 is attached to the terminal electrode 391 with the anisotropic conductive layer 392, so that the terminal portion 390 is formed. Note that as the terminal electrode 391, an electrode obtained in the same step as the wiring for electrically connecting the transistor 310 and the first electrode 351 is preferably used for the uppermost layer.

FIG. 4 shows a top view of the pixel portion. A cross section of a portion represented by a chain line A-A ′ in FIG. 4 corresponds to a cross sectional view of the pixel portion 370 in FIG. 3. Note that in FIG. 4, the partition layer 305, the layer 352, the second electrode 353, the sealing substrate 360, and the like that cover the end portion of the first electrode 351 of the light-emitting element are not illustrated, but are actually provided. Yes. 3 and 4 are diagrams showing an example of the display device of the present invention, and the wiring and the like are appropriately changed depending on the layout.

  In the display device of the present invention, the light emitting display surface of the display device may be one surface or both surfaces. In the case where the first electrode 351 and the second electrode 353 are formed using a transparent conductive film, light from the light-emitting element 350 passes through the substrate 300 and the sealing substrate 360 and is extracted to both sides. In this case, it is preferable to use a transparent material for the sealing substrate 360 and the filler.

  In the case where the second electrode 353 is formed using a metal film and the first electrode 351 is formed using a transparent conductive film, light from the light-emitting element 350 passes through only the substrate 300 and is extracted to one side. That is, it becomes a bottom emission type. In this case, the sealing substrate 360 and the filler need not use a transparent material.

  In the case where the first electrode 351 is formed using a metal film and the second electrode 353 is formed using a transparent conductive film, light from the light-emitting element 350 passes through only the sealing substrate 360 and is extracted to one side. Become. That is, it becomes a top emission type. In this case, the substrate 300 may not use a transparent material.

  In addition, it is necessary to select materials for the first electrode 351 and the second electrode 353 in consideration of a work function. Note that each of the first electrode 351 and the second electrode 353 can be an anode or a cathode depending on the pixel structure. In the case where the polarity of the transistor 310 is a p-channel type, the first electrode 351 is an anode and the second electrode 353 is a cathode. In the case where the polarity of the transistor 310 is an n-channel type, the first electrode 351 is a cathode and the second electrode 353 is an anode.

  In addition, the connection relationship of the transistors 310 and 320, the capacitor 311 and the like is shown in the circuit diagram of FIG. Note that the gate electrode of the transistor 320 is connected to the gate line 504, and one of the source region and the drain region of the transistor 320 is connected to the source line 505. One of the source region and the drain region of the transistor 310 is connected to the current supply line 506.

  The light-emitting element 350 is a diode-type element. When the transistor 310 connected in series with the light-emitting element 350 is a p-channel transistor as in this embodiment, the first electrode 351 of the light-emitting element 350 functions as an anode. To do. On the other hand, when the transistor 310 is an n-channel transistor, the first electrode 351 of the light-emitting element 350 functions as a cathode.

  In the pixel portion of the display device of the present invention, a plurality of light emitting elements driven by a circuit as shown in FIG. 5 are arranged in a matrix. Note that the circuit for driving the light emitting element is not limited to that shown in FIG. For example, a circuit having a configuration in which an erasing line for forcibly erasing an input signal and an erasing transistor used for an erasing operation may be used.

  By including the light-emitting element including the pyrazine derivative of the present invention as in this embodiment mode, a display device having efficient light emission can be obtained.

(Embodiment 5)
In this embodiment, an example of a passive display device is described with reference to FIGS. 6A and 6B are a perspective view and a top view, respectively, of a passive display device to which the present invention is applied. In particular, FIG. 6A is a perspective view of a portion surrounded by a dotted line 658 in FIG. In each of FIGS. 6A and 6B, the corresponding components are denoted by the same reference numerals. In FIG. 6A, a plurality of first electrodes 652 are provided in parallel over the first substrate 651. Each end portion of the first electrode 652 is covered with a partition wall layer 653. Note that in FIG. 6A, the first electrode located on the foremost side is shown for easy understanding of the state where the first electrode provided on the first substrate 651 and the partition wall layer 653 are arranged. A partition layer covering the electrode 652 is not shown. However, in reality, the end portion of the first electrode 652 located closest to the front is also covered with the partition wall layer. A plurality of second electrodes 655 are provided in parallel above the first electrode 652 so as to intersect the first electrode 652. A layer 654 is provided between the first electrode 652 and the second electrode 655. Note that the layer 654 includes a layer containing the pyrazine derivative of the present invention as described in Embodiment Mode 2 or Embodiment Mode 3. In addition, the layer 654 includes at least a light emitting layer, and may include a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and the like. A second substrate 659 is provided over the second electrode 655.

  As shown in FIG. 6B, the first electrode 652 is connected to the first driver circuit 656, and the second electrode 655 is connected to the second driver circuit 660. The portion where the first electrode 652 and the second electrode 655 intersect constitutes the light emitting element of the present invention in which the light emitting layer is sandwiched between the electrodes. Then, the light emitting element of the present invention selected by the signals from the first drive circuit 656 and the second drive circuit 660 emits light. Light emission is extracted to the outside through the first electrode 652, the second electrode 655, or the first electrode 652 and the second electrode 655. The light emitted from the plurality of light emitting elements is combined to display an image. Note that in FIG. 6B, the partition layer 653 and the second substrate 659 are not illustrated for easy understanding of the arrangement of the first electrode 652 and the second electrode 655, but FIG. In fact, these are also provided as shown in

  There is no particular limitation on the material for forming the first electrode 652 and the second electrode 655, but a transparent conductive film may be used so that one or both of the electrodes can transmit visible light. preferable. There is no particular limitation on the material of the first substrate 651 and the second substrate 659, and each of the first substrate 651 and the second substrate 659 is formed using a flexible material using a resin such as a plastic other than a glass substrate. Also good. There is no particular limitation on the partition layer 653, and the partition layer 653 may be formed using either an inorganic insulating film or an organic insulating film. Moreover, you may form using both an inorganic insulating film and an organic insulating film. In addition, the partition layer 653 may be formed using siloxane.

  Note that the layer 654 may be provided independently for each light-emitting element that emits light of different colors. For example, by providing a separate layer 654 for each light-emitting element that emits red, green, and blue, a display device capable of multicolor display can be obtained.

  As in this embodiment mode, by including the light-emitting layer including the pyrazine derivative of the present invention, a passive display device that emits light efficiently can be obtained.

(Embodiment 6)
In this embodiment, a module including a panel including the display device of the present invention as described in Embodiment 4 will be described with reference to FIGS.

  FIG. 7A illustrates a module of an information terminal. A panel 700 includes a pixel portion 701 in which a light-emitting element is provided for each pixel, and a first scanning line for selecting a pixel included in the pixel portion 701. A driver circuit 702a, a second scan line driver circuit 702b, and a signal line driver circuit 703 that supplies a video signal to a selected pixel are provided. The pixel portion 701 corresponds to the pixel portion or the like in FIGS. 3 and 4 described in Embodiment Mode 4.

  A printed wiring board 710 is connected to the panel 700 via an FPC (flexible printed circuit) 704. The printed wiring board 710 is mounted with a controller 711, a CPU (central processing unit) 712, a memory 713, a power supply circuit 714, an audio processing circuit 715, a transmission / reception circuit 716, and other elements such as resistors, buffers, and capacitive elements. Yes.

  Various control signals are input / output via an interface (I / F) unit 717 provided on the printed wiring board 710. Further, an antenna port 718 for transmitting and receiving signals to and from the antenna is provided on the printed wiring board 710.

  Note that although the printed wiring board 710 is connected to the panel 700 through the FPC 704 in this embodiment mode, the present invention is not limited to this. The controller 711, the sound processing circuit 715, the memory 713, the CPU 712, or the power supply circuit 714 may be directly mounted on the panel 700 by using a COG (Chip on Glass) method. Further, the printed wiring board 710 is provided with various elements such as a capacitor element and a buffer to prevent noise from being applied to the power supply voltage and the signal and the rise of the signal from being slowed down.

  FIG. 7B shows a block diagram of the module shown in FIG. This module includes a control signal generation circuit 720, a decoder 721, a register 722, an arithmetic circuit 723, a RAM 724, an interface 725 for the CPU, and the like as the CPU 712. Various signals input to the CPU 712 via the interface 725 are once held in the register 722 and then input to the arithmetic circuit 723, the decoder 721, and the like. The arithmetic circuit 723 performs an operation based on the input signal and designates a place to send various commands. On the other hand, the signal input to the decoder 721 is decoded and input to the control signal generation circuit 720. The control signal generation circuit 720 generates a signal including various instructions based on the input signal, and a location designated in the arithmetic circuit 723, specifically, a memory 713, a transmission / reception circuit 716, an audio processing circuit 715, a controller 711, and the like. Send to.

  The memory 713 includes a VRAM 731, a DRAM 732, a flash memory 733, and the like. The VRAM 731 stores image data to be displayed on the panel 700, the DRAM 732 stores image data or audio data, and the flash memory 733 stores various programs.

  In the power supply circuit 714, a power supply voltage to be supplied to the panel 700, the controller 711, the CPU 712, the sound processing circuit 715, the memory 713, and the transmission / reception circuit 716 is generated. Depending on the specifications of the panel, the power supply circuit 714 may be provided with a current source.

  The memory 713, the transmission / reception circuit 716, the audio processing circuit 715, and the controller 711 operate according to the received commands. The operation will be briefly described below.

  A signal input from the input unit 734 is sent to the CPU 712 mounted on the printed wiring board 710 via the interface (I / F) unit 717. The control signal generation circuit 720 converts the image data stored in the VRAM 731 into a predetermined format according to a signal sent from the input unit 734 such as a pointing device or a keyboard, and sends the image data to the controller 711.

  The controller 711 performs data processing on a signal including image data sent from the CPU 712 in accordance with the panel specifications, and supplies the processed signal to the panel 700. In addition, the controller 711 generates an Hsync signal, a Vsync signal, a clock signal CLK, an AC voltage (AC Cont), and a switching signal L / R based on the power supply voltage input from the power supply circuit 714 and various signals input from the CPU 712. Generated and supplied to the panel 700.

  In the transmission / reception circuit 716, signals transmitted / received as radio waves in the antenna 743 are processed. Specifically, high-frequency signals such as an isolator, a band pass filter, a VCO (Voltage Controlled Oscillator), an LPF (Low Pass Filter), a coupler, and a balun Includes circuitry. A signal including audio information among signals transmitted and received in the transmission / reception circuit 716 is sent to the audio processing circuit 715 in accordance with a command from the CPU 712.

  A signal including audio information sent in accordance with a command from the CPU 712 is demodulated into an audio signal by the audio processing circuit 715 and sent to the speaker 748. The audio signal sent from the microphone 747 is modulated by the audio processing circuit 715 and sent to the transmission / reception circuit 716 in accordance with a command from the CPU 712.

  The controller 711, the CPU 712, the power supply circuit 714, the sound processing circuit 715, and the memory 713 can be mounted as a package of the printed wiring board 710. This embodiment can be applied to any circuit other than a high-frequency circuit such as an isolator, a band-pass filter, a VCO (Voltage Controlled Oscillator), an LPF (Low Pass Filter), a coupler, and a balun.

  As described above, since the light-emitting element including the pyrazine derivative of the present invention is included as a light-emitting element constituting the panel, a module having efficient light emission can be obtained.

(Embodiment 7)
In this embodiment mode, an example in which a module including the display device of the present invention as shown in Embodiment Modes 5 and 6 is mounted on a portable small-sized telephone (mobile phone) using radio is shown in FIGS. 8 is used.

  The display panel 800 is detachably incorporated in the housing 801 so that the display panel 800 can be easily fixed to the printed wiring board 810. The shape and size of the housing 801 can be changed as appropriate in accordance with an electronic device to be incorporated.

  In FIG. 8, a housing 801 to which a display panel 800 (corresponding to the panel 700 in FIGS. 7A and 7B) is fixed is fitted to a printed wiring board 810 (corresponding to the printed wiring board 610 in FIG. 7), and the module Assembled as. On the printed wiring board 810, a controller, a CPU, a memory, a power supply circuit, a resistor, a buffer, a capacitor, and the like are mounted. Further, a signal processing circuit 803 such as an audio processing circuit including a microphone 804 and a speaker 805 and a transmission / reception circuit is provided. As described with reference to FIGS. 7A and 7B, the display panel 800 is connected to the printed wiring board 810 through the FPC.

  Such a module 820, input means 808, and battery 807 are housed in a housing 806. A pixel portion of the display panel 800 is arranged so as to be visible from an opening window formed in the housing 806.

  Note that the housing 806 illustrated in FIG. 8 illustrates the appearance of a telephone as an example, and the present invention is not limited to this, and can be transformed into various modes depending on functions and uses.

  As described above, since the light-emitting element including the pyrazine derivative of the present invention is included as a light-emitting element constituting the display panel, a module such as a small phone (mobile phone) having a display portion that emits light efficiently can be obtained.

(Embodiment 8)
In this embodiment, various electronic devices are described. For example, a camera such as a video camera or a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproduction device (car audio, audio component, etc.), a personal computer, a game machine, a portable information terminal (mobile computer, cellular phone) , Portable game machines, electronic books, etc.), image playback device provided with a recording medium (specifically, a device provided with a display capable of playing back a recording medium such as Digital Versatile Disc (DVD) and displaying the image) Etc. will be explained.

  FIG. 9A illustrates a digital camera, which includes a main body 1801, a display portion 1802, an imaging portion, operation keys 1804, a shutter 1805, and the like. Note that FIG. 9A is a view from the display portion 1802 side, and the imaging portion is not shown. When the display portion 1802 includes the light-emitting element including the pyrazine derivative of the present invention, favorable display can be performed.

  FIG. 9B illustrates a laptop personal computer, which includes a main body 1821, a housing 1822, a display portion 1823, a keyboard 1824, an external connection port 1825, a pointing mouse 1826, and the like. When the display portion 1823 includes a light-emitting element including the pyrazine derivative of the present invention, favorable display can be performed.

  FIG. 9C shows a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 1841, a housing 1842, a display portion A1843, a display portion B1844, a recording medium (DVD or the like). A reading unit 1845, operation keys 1846, a speaker unit 1847, and the like are included. The display portion A1843 mainly displays image information, and the display portion B1844 mainly displays character information. Note that an image reproducing device provided with a recording medium includes a home game machine and the like. When the display portion A1843 and the display portion B1844 each include the light-emitting element including the pyrazine derivative of the present invention, favorable display can be performed.

  FIG. 9D illustrates a display device, which includes a housing 1861, a support base 1862, a display portion 1863, a speaker 1864, a video input terminal 1865, and the like. The display device includes all information display devices such as a computer, a television receiver, and an advertisement display. When the display portion 1863 includes the light-emitting element including the pyrazine derivative of the present invention, favorable display can be performed.

  As described above, since the display portion of various electronic devices includes the light-emitting element including the pyrazine derivative of the present invention, favorable display can be obtained.

(Synthesis Example 1)
As an example of the pyrazine derivative of the present invention, a compound represented by the structural formula (s-9), 2,3-bis {4- [N, N-di (biphenyl-4-yl) amino] phenyl} pyrazine , BBAPPr) will be described.

[Step 1: Method for synthesizing 2,3-bis (4-bromophenyl) pyrazine (hereinafter referred to as PPr)]
(1) Synthesis of 2,3-bis (4-bromophenyl) -5,6-dihydropyrazine.
After putting 10 g (27 mmol) of 4,4′-dibromobenzyl into a 300 mL three-necked flask and adding 200 mL of chloroform to dissolve, 3.0 mL (45 mmol) of ethylenediamine was added, and this mixture was heated and stirred at 80 ° C. for 5 hours to react. I let you. After the reaction, the reaction solution was washed with water and the solvent was distilled off to obtain 10 g of a light yellow solid of 2,3-bis (4-bromophenyl) -5,6-dihydropyrazine in a yield of 94%. (Synthesis scheme (e-1)).

(2) Synthesis of PPr.
After putting 10 g (27 mmol) of 2,3-bis (4-bromophenyl) -5,6-dihydropyrazine into a 500 mL three-necked flask and adding 100 mL of ethanol to dissolve, 8.8 g (54 mmol) of iron (III) chloride was added. In addition, this mixture was heated and stirred at 60 ° C. for 30 minutes to be reacted. After the reaction, 300 mL of water was added to the reaction mixture, and the precipitated solid was dissolved in toluene. The mixture was washed with saturated brine, and the solid obtained by concentrating the solvent was purified by silica column chromatography. Purification by the silica column chromatography (hereinafter also referred to as column purification) was performed by first using toluene as a developing solvent and then using a mixed solvent of toluene: ethyl acetate = 1: 1 as a developing solvent. After column purification, the solvent of the obtained solution was concentrated to obtain 6.3 g of PPr orange solid in a yield of 60% (synthesis scheme (e-2)).

[Step 2: Synthesis Method of Di (biphenyl-4-yl) amine (hereinafter referred to as BBA)]
(1) Synthesis of 4,4′-dibromodiphenylamine.
50 g (169 mmol) of diphenylamine and 1000 mL of ethyl acetate were put into a 2000 mL Erlenmeyer flask, 108 g (605 mmol) of N-bromosuccinimide was added, and the mixture was stirred at room temperature for about 12 hours to be reacted. After the reaction, the reaction solution was washed with water, the aqueous layer was extracted with ethyl acetate, and the separated organic layer was dried over magnesium sulfate. The filtrate was concentrated and the solid obtained was washed with hexane. , 4′-Dibromodiphenylamine was obtained as a white solid (73 g, yield 76%) (Synthesis scheme (e-3)).

(2) Synthesis of BBA.
500 mL three-neck flask containing 30 g (92 mmol) of 4,4′-dibromodiphenylamine, 25 g (204 mmol) of phenylboronic acid, 0.46 g (2.0 mmol) of palladium acetate, and 1.4 g (4.5 mmol) of tris (o-tolyl) phosphine The flask was purged with nitrogen, and then 300 mL of ethylene glycol dimethyl ether and 300 mL of a 2.0 mol / L potassium carbonate aqueous solution were added, and this mixture was stirred at 80 ° C. for 5 hours to be reacted. After the reaction, the precipitate was filtered and the filtrate was recrystallized from chloroform and hexane to obtain 23 g of BBA white solid in a yield of 78% (Synthesis scheme (e-4)).

[Step 3: Synthesis method of BBAPPr]
PPr 1.5 g (3.9 mmol), BBA 2.5 g (7.7 mmol) and sodium-tert-butoxide 1.5 g (15.4 mmol) were placed in a 200 mL three-necked flask, and the inside of the flask was purged with nitrogen. 1.0 mL of 10 wt% hexane solution of tri-tert-butylphosphine and 0.1 g (0.2 mmol) of bis (dibenzylideneacetone) palladium (0) were added, and this mixture was heated and stirred at 80 ° C. for 3 hours to be reacted. It was. After the reaction, the reaction mixture was filtered through Florisil, Celite, and alumina. The filtrate was washed with water, dried over magnesium sulfate, and filtered. The solid obtained by concentrating the filtrate was dissolved in toluene and purified by silica column chromatography. The column purification was performed by first using toluene as a developing solvent and then using a mixed solvent of toluene: ethyl acetate = 9: 1 as a developing solvent. After column purification, the resulting solution was recrystallized with chloroform and hexane to obtain 0.51 g of yellow solid with a yield of 15%.

  The obtained yellow solid was purified by sublimation by a train sublimation method. The sublimation purification was performed at 280 ° C. for 12 hours under a reduced pressure of 7 Pa, with an argon flow rate of 3 mL / min. When the amount of the yellow solid obtained previously was 0.51 g, 0.28 g of the target BBAPPr yellow solid was obtained in a yield of 54% (Synthesis scheme (e-5)).

The analysis results of BBAPPr by the proton nuclear magnetic resonance method ( ¹ H-NMR) are shown below. Note that tetramethylsilane (abbreviation: TMS) was used as a reference substance.
¹ H-NMR (300 MHz, CDCl ₃ ); δ = 7.12-7.58 (m, 44H), δ = 8.54 (s, 2H)

Further, ¹ H-NMR charts of BBAPPr are shown in FIGS. Note that FIG. 10B is an enlarged view of the range of 6.5 ppm to 9.0 ppm in the chart of FIG.

  Further, FIG. 11 shows an absorption spectrum and an emission spectrum in a state where BBAPPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 11, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). In FIG. 11, the spectrum shown in (a) is an absorption spectrum. The spectrum shown in (b) is an emission spectrum (excitation wavelength: 347 nm).

  Moreover, the result of having investigated about the oxidation-reduction reaction characteristic of BBAPPr by the cyclic voltammetry (CV) measurement is shown in FIG. As the measuring apparatus, an electrochemical analyzer (manufactured by BAS Co., Ltd., ALS model 600A) was used.

The solution used for the CV measurement uses dehydrated dimethylformamide (abbreviation: DMF) as a solvent, and has a concentration of 100 mmol / L of tetra-n-butylammonium perchlorate (n-Bu ₄ NClO ₄ ) as a supporting electrolyte. And BBAPPr to be measured was further dissolved to a concentration of 1 mmol / L. In addition, as a working electrode, a platinum electrode (manufactured by BAS Co., Ltd., PTE platinum electrode), and as an auxiliary electrode, a platinum electrode (manufactured by BAS Inc., Pt counter electrode for VC-3 ( 5 cm)), and an Ag / Ag ⁺ electrode (manufactured by BAS Co., Ltd., RE5 non-aqueous solvent reference electrode) was used as a reference electrode.

  The oxidation reaction characteristics were measured by first scanning the potential of the working electrode with respect to the reference electrode from 0.10 V to 1.00 V, and then scanning from 1.00 V to 0.10 V. The scan speed for CV measurement was set to 0.1 V / s.

  The reduction reaction characteristics were measured by first scanning the potential of the working electrode with respect to the reference electrode from −0.84 to −2.70 V, and then scanning from −2.70 V to −0.84 V. The scan speed for CV measurement was set to 0.1 V / s.

  FIG. 12A shows a CV curve obtained by examining the oxidation reaction characteristics of BBAPPr. Further, FIG. 12B shows a CV curve examined for reduction characteristics. In FIG. 12, the horizontal axis represents the potential of the working electrode with respect to the reference electrode, and the vertical axis represents the value of current flowing between the working electrode and the auxiliary electrode. As shown in FIG. 12, BBAPPr clearly observed both a peak indicating oxidation and a peak indicating reduction. That is, it was found that BBAPPr is a substance that easily contains holes and electrons. From this, it was found that BBAPPr is a bipolar substance.

(Synthesis Example 2)
As an example of the pyrazine derivative of the present invention, a compound represented by the structural formula (s-16), 2,3-bis {4- [N- (biphenyl-4-yl) -N-phenylamino] phenyl} pyrazine ( Hereinafter, a synthesis method of BPhAPPr) will be described.

[Step 1: Synthesis method of 4-phenyldiphenylamine (hereinafter referred to as BPhA)]
4-Bromobiphenyl 40 g (172 mmol), aniline 19 g (206 mmol), bis (dibenzylideneacetone) palladium (0) 0.99 g (1.7 mmol), sodium-tert-butoxide 41 g (429 mmol) were placed in a 500 mL three-necked flask, After the inside of the flask was purged with nitrogen, 300 mL of toluene and 5.9 g (2.9 mmol) of a 10 wt% hexane solution of tri-tert-butylphosphine were added, and the mixture was stirred at 80 ° C. for 2 hours to be reacted. . After the reaction, the reaction mixture was washed with water, the aqueous layer was extracted with toluene, and the separated organic layer was dried over magnesium sulfate and filtered. The solid obtained by concentrating the filtrate was purified by silica column chromatography to obtain 33 g of a target white solid of BPhA in a yield of 80% (synthesis scheme (f-1)). Column purification was performed using toluene as a developing solvent.

[Step 2: Method for synthesizing BPhAPPr]
PPr 0.74 g (1.9 mmol), BPhA 0.93 g (3.9 mmol), and sodium-tert-butoxide 0.8 g were placed in a 200 mL three-necked flask, and the inside of the flask was purged with nitrogen, followed by toluene 70 mL, tri-tert-butyl. 1.5 mL of a 10 wt% hexane solution of phosphine and 0.2 g (0.4 mmol) of bis (dibenzylideneacetone) palladium (0) were added, and this mixture was heated and stirred at 80 ° C. for 3 hours to be reacted. After the reaction, the reaction mixture was filtered through Florisil, Celite, and alumina. The filtrate was washed with water, dried over magnesium sulfate, and filtered. The solid obtained by concentrating the filtrate was recrystallized from dichloromethane and hexane to obtain 1.0 g of yellow solid with a yield of 70%.

  The obtained yellow solid was purified by sublimation by a train sublimation method. The sublimation purification was carried out at 300 ° C. for 12 hours under a reduced pressure of 7 Pa with an argon flow rate of 3 mL / min. When the amount of the yellow solid obtained previously was 1.0 g, 0.90 g of a target yellow solid of BPhAPPr was obtained in a yield of 90% (synthesis scheme (f-2)).

The analysis results of BPhAPPr by proton nuclear magnetic resonance ( ¹ H-NMR) are shown below. Note that tetramethylsilane (abbreviation: TMS) was used as a reference substance.
¹ H-NMR (300 MHz, CDCl ₃ ); δ = 7.06-7.44 (m, 28H), δ = 7.49 (d, J = 9.0, 4H), δ = 7.56 (d , J = 7.2, 4H), δ = 8.52 (s, 2H)

In addition, ¹ H-NMR charts of BPhAPPr are shown in FIGS. Note that FIG. 13B is an enlarged view of the range of 6.5 ppm to 9.0 ppm in the chart of FIG.

  Further, FIG. 14 shows an absorption spectrum and an emission spectrum in a state where BPhAPPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 14, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 14A is an absorption spectrum, and the spectrum shown in FIG. 14B is an emission spectrum (excitation wavelength 352 nm).

  Further, FIG. 15 shows an absorption spectrum and an emission spectrum of BPhAPPr in a single film state. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 15, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 15A is an absorption spectrum, and the spectrum shown in FIG. 15B is an emission spectrum (excitation wavelength 336 nm).

(Synthesis Example 3)
As an example of the pyrazine derivative of the present invention, a method for synthesizing a compound represented by the structural formula (s-13), 2,3-bis [4- (N, N-diphenylamino) phenyl] pyrazine (hereinafter referred to as DPhAPPr) Will be described.

[Step 1: Synthesis method of DPhAPPr]
200 mL of PPr 3.0 g (7.7 mmol), diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as DPhA) 2.6 g (15.4 mmol), sodium-tert-butoxide 3.0 g (30.8 mmol) After putting into a three-necked flask and replacing the inside of the flask with nitrogen, 40 mL of toluene, 0.3 mL of a 10 wt% hexane solution of tri-tert-butylphosphine, 0.3 g (0.6 mmol) of bis (dibenzylideneacetone) palladium (0) The mixture was heated and stirred at 80 ° C. for 5 hours to be reacted. After the reaction, the reaction mixture was filtered through Florisil, Celite, and alumina. The filtrate was washed with water, dried over magnesium sulfate, and filtered. The solid obtained by concentrating the filtrate was dissolved in toluene and purified by silica column chromatography. The column purification was performed by first using toluene as a developing solvent and then using a mixed solvent of toluene: ethyl acetate = 9: 1 as a developing solvent. After column purification, the resulting solution was recrystallized with chloroform and hexane to obtain 3.5 g of yellow solid with a yield of 80%.

  The obtained yellow solid was purified by sublimation by a train sublimation method. The sublimation purification was performed at 240 ° C. for 12 hours under a reduced pressure of 7 Pa with an argon flow rate of 3 mL / min. When the amount of the yellow solid charged was 3.5 g, 3.0 g of the target DPhAPPr yellow solid was obtained in a yield of 86% (synthesis scheme (h-1)).

Analysis results of DPhAPPr by proton nuclear magnetic resonance ( ¹ H-NMR) are shown below. Note that tetramethylsilane (abbreviation: TMS) was used as a reference substance.
¹ H-NMR (300 MHz, CDCl ₃ ); δ = 6.98-7.14 (m, 16H), δ = 7.23-7.30 (m, 8H), δ = 7.37 (d, J = 9.0, 4H), δ = 8.50 (s, 2H)

In addition, ¹ H-NMR of DPhAPPr is shown in FIGS. Note that FIG. 16B is an enlarged view of the range of 6.5 ppm to 9.0 ppm in the chart of FIG.

  Further, FIG. 17 shows an absorption spectrum and an emission spectrum in a state where DPhAPPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 17, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 17A is an absorption spectrum, and the spectrum shown in FIG. 17B is an emission spectrum (excitation wavelength 364 nm).

  Further, FIG. 18 shows an absorption spectrum and an emission spectrum of DPhAPPr in a single film state. In FIG. 18, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 18A is an absorption spectrum, and the spectrum shown in FIG. 18B is an emission spectrum (excitation wavelength: 368 nm).

(Synthesis Example 4)
As an example of the pyrazine derivative of the present invention, a compound represented by the structural formula (s-53), 2,3-bis {4- [N- (4-diphenylaminophenyl) -N-phenylamino] phenyl} pyrazine , DPAPPr) will be described.

[Step 1: Method for synthesizing N, N, N′-triphenyl-1,4-phenylenediamine (hereinafter referred to as DPA)]
(1) Synthesis of 4-bromotriphenylamine.
A 1000 mL Erlenmeyer flask was charged with 25 g (100 mmol) of triphenylamine, 18 g (100 mmol) of N-bromosuccinimide, and 400 mL of ethyl acetate, and stirred for about 12 hours at room temperature in air for reaction. After completion of the reaction, the reaction solution was washed twice with a saturated aqueous sodium carbonate solution, and then the organic layer and the aqueous layer were separated. The aqueous layer was extracted twice with ethyl acetate, and then the extract and the organic layer were combined, washed with saturated brine, dried over magnesium sulfate, and filtered. The filtrate was concentrated, and the obtained solid was recrystallized with ethyl acetate and hexane to obtain 22 g of 4-bromotriphenylamine as a white powdery solid in a yield of 66% (Synthesis scheme (i-1)). ).

(2) Synthesis of DPA.
4-bromotriphenylamine 0.56 g (6 mmol), bis (dibenzylideneacetone) palladium (0) 0.35 g (0.6 mmol), sodium-tert-butoxide 0.58 g (6 mmol) was placed in a 100 mL three-necked flask, After adding 5 mL of toluene and purging the inside of the flask with nitrogen, 0.56 g (6 mmol) of aniline and 0.37 mL (1.8 mmol) of a 10 wt% hexane solution of tri-tert-butylphosphine were added. The mixture was heated and stirred for a time to react. After the reaction, saturated brine was added to the reaction mixture to terminate the reaction, and the aqueous layer was extracted with about 100 mL of ethyl acetate to separate the organic layer. The organic layer was dried over magnesium sulfate and filtered. The solid obtained by concentrating the filtrate was purified by silica column chromatography to obtain 0.24 g of a light yellow powdery solid of DPA, which was the target product, in a yield of 42% (synthesis scheme (i -2)). For column purification, a mixed solvent of ethyl acetate: hexane = 1: 20 was used as a developing solvent.

[Step 2: Synthesis method of DPAPPr]
PPr 0.52 g (1.3 mmol), DPA 0.90 g (2.7 mmol), sodium tert-butoxide 0.8 g (8.3 mmol) were placed in a 100 mL three-necked flask, and the inside of the flask was purged with nitrogen, and then 15 mL of toluene, 0.1 mL of a 10 wt% hexane solution of tri-tert-butylphosphine was added, and the inside of the flask was again purged with nitrogen. Further, 0.1 g (0.2 mmol) of bis (dibenzylideneacetone) palladium (0) was added, and this mixture was heated and stirred at 120 ° C. for 5 hours to be reacted. After the reaction, the reaction mixture was filtered through celite. The filtrate was washed with water, dried over magnesium sulfate, and filtered. The solid obtained by concentrating the filtrate was dissolved in toluene and purified by silica column chromatography. Column purification was performed by first using toluene as a developing solvent and then using a mixed solvent of toluene: ethyl acetate = 9: 1 as a developing solvent. After column purification, the obtained solution was recrystallized with chloroform and hexane to obtain 0.27 g of a target yellow solid of DPAPPr in a yield of 80% (Synthesis scheme (i-3)).

The analysis results of DPAPPr by the proton nuclear magnetic resonance method ( ¹ H-NMR) are shown below. Note that tetramethylsilane (abbreviation: TMS) was used as a reference substance.
¹ H-NMR (300 MHz, CDCl ₃ ); δ = 6.9-9.26 (m, 42H), δ = 7.37 (d, J = 8.4, 4H), δ = 8.49 (s 2H)

In addition, ¹ H-NMR charts of DPAPPr are shown in FIGS. Note that FIG. 19B is an enlarged view of the range of 6.5 ppm to 9.0 ppm in the chart of FIG.

  Further, FIG. 20 shows an absorption spectrum and an emission spectrum in a state where DPAPPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 20, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum illustrated in FIG. 20A is an absorption spectrum, and the spectrum illustrated in FIG. 20B is an emission spectrum (excitation wavelength: 358 nm).

(Synthesis Example 5)
As an example of the pyrazine derivative of the present invention, a compound represented by the structural formula (s-77), 2,3-bis {4- [N-phenyl-N- (9-phenylcarbazol-3-yl)] A synthesis method of amino] phenyl} pyrazine (hereinafter referred to as PCAPPr) will be described.

[Step 1: Method for synthesizing N-phenyl- (9-phenylcarbazol-3-yl) amine (hereinafter referred to as PCA)]
(1) Synthesis of 3-bromo-9-phenylcarbazole.
N-phenylcarbazole (24.3 g, 100 mmol) was dissolved in glacial acetic acid (600 mL), N-bromosuccinimide (17.8 g, 100 mmol) was slowly added, and the mixture was stirred at room temperature for about 12 hours. This glacial acetic acid solution was added dropwise to 1000 mL of ice water with stirring. After the dropwise addition, the precipitated white solid was washed with water three times. This solid was dissolved in 150 mL of diethyl ether and washed with a saturated aqueous sodium hydrogen carbonate solution and water, and then the aqueous layer and the organic layer were separated. This organic layer was dried over magnesium sulfate, filtered, and about 50 mL of methanol was added to the solid obtained by concentrating the filtrate, and the mixture was uniformly dissolved by irradiation with ultrasonic waves. This solution was allowed to stand to precipitate a white solid. This was filtered and the residue was dried to obtain 28.4 g of white solid of 3-bromo-9-phenylcarbazole in a yield of 88% (Synthesis scheme (j-1)).

(2) Synthesis of PCA.
Under nitrogen, 19 g (60 mmol) of 3-bromo-9-phenylcarbazole, 340 mg (0.6 mmol) of bis (dibenzylideneacetone) palladium (0) (abbreviation: Pd (dba) ₂ ), 1,1-bis (diphenyl) Phosphino) ferrocene (abbreviation: DPPF) 1.6 g (3.0 mmol) and sodium-tert-butoxide (abbreviation: t-BuONa) 13 g (180 mmol) were mixed with dehydrated xylene 110 mL and aniline 7.0 g (75 mmol). added. This was heated and stirred at 90 ° C. for 7.5 hours in a nitrogen atmosphere. After completion of the reaction, about 500 mL of toluene warmed to 50 ° C. was added to this suspension, and this was filtered through Florisil, alumina, and celite. The solid obtained by concentrating the filtrate was added with hexane and ethyl acetate and irradiated with ultrasonic waves. The obtained suspension was filtered, and the residue was dried to obtain 15 g of a light yellow solid of PCA in a yield of 75% (Synthesis scheme (j-2)).

[Step 2: Method of synthesizing PCAPPr]
PPr 1.0 g (2.6 mmol), PCA 1.9 g (10.4 mmol) and sodium-tert-butoxide 1.0 g (10.3 mmol) were placed in a 100 mL three-necked flask, and the inside of the flask was purged with nitrogen, then 15 mL of toluene, 0.3 mL of a 10 wt% hexane solution of tri-tert-butylphosphine and 0.1 g (0.2 mmol) of bis (dibenzylideneacetone) palladium (0) were added, and the mixture was heated and stirred at 80 ° C. for 4 hours to be reacted. It was. After the reaction, the reaction mixture was filtered through Florisil, Celite, and alumina, and the filtrate was washed with water, dried over magnesium sulfate, and then filtered. The solid obtained by concentrating the filtrate was dissolved in toluene and purified by silica column chromatography. Column purification was performed by first using toluene as a developing solvent and then using a mixed solvent of toluene: ethyl acetate = 9: 1 as a developing solvent. After column purification, the resulting solution was recrystallized with chloroform and hexane to obtain 1.3 g of yellow solid with a yield of 57%.

  The obtained yellow solid was purified by sublimation by a train sublimation method. The sublimation purification was performed at 330 ° C. for 12 hours under a reduced pressure of 7 Pa with an argon flow rate of 3 mL / min. When the amount of the yellow solid obtained previously was 1.2 g, 0.32 g of a target yellow solid of PCAPPr was obtained in a yield of 26% (Synthesis scheme (j-3)).

The analysis results of PCAPPr by the proton nuclear magnetic resonance method ( ¹ H-NMR) are shown below. Note that tetramethylsilane (abbreviation: TMS) was used as a reference substance.
¹ H-NMR (CDCl ₃ , 300 MHz): δ = 6.97-7.67 (m, 40H), δ = 7.93-7.97 (m, 2H), δ = 8.48 (s, 2H )

A ¹ H-NMR chart of PCAPPr is shown in FIGS. Note that FIG. 21B is an enlarged view of the range of 6.5 ppm to 9.0 ppm in the chart of FIG.

  Further, FIG. 22 shows an absorption spectrum and an emission spectrum in a state where PCAPPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 22, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 22A is an absorption spectrum, and the spectrum shown in FIG. 22B is an emission spectrum (excitation wavelength: 367 nm).

  Further, FIG. 23 shows an absorption spectrum and an emission spectrum of PCAPPr in a single film state. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 23, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). Moreover, the spectrum shown to Fig.23 (a) is an absorption spectrum, and the spectrum shown to FIG.23 (b) is an emission spectrum (excitation wavelength 376nm).

(Synthesis Example 6)
As an example of the pyrazine derivative of the present invention, a compound represented by the structural formula (s-103), 2,3-bis (4- {N- [4- (carbazol-9-yl) phenyl] -N-phenylamino, } A method for synthesizing phenyl) pyrazine (hereinafter referred to as YGAPPr) will be described.

[Step 1: Method for synthesizing 4- (carbazol-9-yl) diphenylamine (hereinafter referred to as YGA)]
(1) Synthesis of 9- (4-bromophenyl) carbazole.
p-Dibromobenzene 56 g (240 mmol), carbazole 31 g (180 mmol), copper iodide 4.6 g (24 mmol), potassium carbonate 66 g (480 mmol), 18-crown-6-ether 2.1 g (8 mmol) in a 300 mL three-necked flask. The flask was purged with nitrogen, 8 mL of N, N′-dimethylpropyleneurea was added, and the mixture was stirred at 180 ° C. for 6 hours to be reacted. After the reaction, the reaction mixture was cooled to room temperature, and then the precipitate was removed by suction filtration. The filtrate was washed with diluted hydrochloric acid, saturated aqueous sodium hydrogen carbonate solution and saturated brine in that order, dried over magnesium sulfate, and filtered. The oily substance obtained by concentrating the filtrate was purified by silica column chromatography. For column purification, a mixed solvent of hexane: ethyl acetate = 9: 1 was used as a developing solvent. After column purification, the obtained solution was recrystallized with chloroform and hexane to obtain 21 g of a light brown solid of 9- (4-bromophenyl) carbazole in a yield of 35% (Synthesis scheme (k-1)). .

(2) Synthesis of YGA.
5.4 g (17 mmol) of 9- (4-bromophenyl) carbazole, 1.8 mL (20 mmol) of aniline, 0.1 g (0.2 mmol) of bis (dibenzylideneacetone) palladium (0), sodium-tert-butoxide 9 g (40 mmol) was placed in a 200 mL three-necked flask, and the inside of the flask was purged with nitrogen. Then, 0.1 mL of a 10 wt% hexane solution of tri-tert-butylphosphine and 50 mL of toluene were added, and the mixture was stirred at 80 ° C. for 6 hours. And reacted. After the reaction, the reaction mixture was filtered through Florisil, Celite, and alumina. The filtrate was washed with water and saturated brine, dried over magnesium sulfate, and then naturally filtered. The oily substance obtained by concentrating the filtrate was purified by silica column chromatography to obtain 4.1 g of YGA white solid in a yield of 73% (synthesis scheme (k-2)). For column purification, a mixed solvent of hexane: ethyl acetate = 9: 1 was used as a developing solvent.

[Step 2: YGAPPr synthesis method]
PPr 2.0 g (5.1 mmol), YGA 3.5 g (10.5 mmol), sodium-tert-butoxide 1.9 g (20.1 mmol) were placed in a 100 mL three-necked flask, and the inside of the flask was purged with nitrogen, and then toluene 30 mL, 0.2 mL of a 10 wt% hexane solution of tri-tert-butylphosphine was added, and the inside of the flask was again purged with nitrogen. Further, 0.2 g (0.4 mmol) of bis (dibenzylideneacetone) palladium (0) was added, and this mixture was heated and stirred at 120 ° C. for 5 hours to be reacted. After the reaction, the reaction mixture was filtered through celite, the filtrate was washed with water, dried over magnesium sulfate, and then filtered. The solid obtained by concentrating the filtrate was dissolved in toluene and purified by silica column chromatography. Column purification was performed by first using toluene as a developing solvent and then using a mixed solvent of toluene: ethyl acetate = 9: 1 as a developing solvent. After column purification, the obtained solution was recrystallized with chloroform and hexane to obtain 4.1 g of yellow solid with a yield of 89%.

  The obtained yellow solid was purified by sublimation by a train sublimation method. The sublimation purification was performed at 320 ° C. for 12 hours under a reduced pressure of 7 Pa with an argon flow rate of 3 mL / min. When the amount of the yellow solid obtained previously was 3.4 g, 0.65 g of the target YGAPPr yellow solid was obtained in a yield of 19% (synthesis scheme (k-3)).

The analysis result of YGAPPr by the proton nuclear magnetic resonance method ( ¹ H-NMR) is shown below. Note that tetramethylsilane (abbreviation: TMS) was used as a reference substance.
¹ H-NMR (300 MHz, CDCl ₃ ): δ = 7.11 (d, J = 12.0, 4H), δ = 7.16-7.44 (m, 26H), δ = 7.48 (d , J = 8.4, 4H), δ = 8.13 (d, J = 7.8, 4H), δ = 8.55 (s, 2H)

In addition, ¹ H-NMR charts of YGAPPr are shown in FIGS. Note that FIG. 24B is an enlarged view of the range of 6.5 ppm to 9.0 ppm in the chart of FIG.

  Further, FIG. 25 shows an absorption spectrum and an emission spectrum in a state where YGAPPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 25, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 25A is an absorption spectrum, and the spectrum shown in FIG. 25B is an emission spectrum (excitation wavelength 355 nm).

  In addition, FIG. 26 shows an absorption spectrum and an emission spectrum of YGAPPr in a single film state. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 26, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 26A is an absorption spectrum, and the spectrum shown in FIG. 26B is an emission spectrum (excitation wavelength 375 nm) in a single film state.

  In Example 7, DPhAPPr (structural formula (s-13)), which is an example of the pyrazine derivative of the present invention synthesized in Synthesis Example 3 of Example 3, was used as a host material for the light-emitting layer, and a phosphorescent compound was used as a guest. An example of a light emitting element used as a material will be specifically exemplified. The element structure is shown in FIG.

  First, a glass substrate 7000 on which indium tin oxide containing silicon (ITSO) with a thickness of 110 nm was formed was prepared. The periphery of ITSO was covered with an insulating film. At this time, an insulating film was formed so as to expose the ITSO surface with a size of 2 mm square. Note that ITSO is a first electrode 7001 functioning as an anode of the light-emitting element. As a pretreatment for forming a light-emitting element over the substrate 7000 on which the first electrode 7001 is formed, the surface of the substrate 7000 on which the first electrode 7001 is formed is cleaned using a porous resin brush, and the temperature is 200 ° C. Then, UV ozone treatment was performed for 370 seconds.

  Next, the substrate 7000 was fixed to a holder provided in the vacuum evaporation apparatus so that the surface on which the first electrode 7001 was formed faced down.

Next, the inside of the vacuum evaporation apparatus was decompressed to 10 ⁻⁴ Pa. Then, the ratio of NPB and molybdenum oxide (VI) represented by the following structural formula (s-116) on the first electrode 7001 is NPB: molybdenum oxide (VI) = 4: 1 in terms of mass ratio. Thus, a hole injection layer 7002 was formed by co-evaporation. The film thickness was 50 nm. Note that co-evaporation is an evaporation method in which a plurality of different substances are simultaneously evaporated from different evaporation sources.

Next, NPB was deposited to a thickness of 10 nm on the hole injection layer 7002 to form a hole transport layer 7003. Further, over the hole-transport layer 7003, DPhAPPr (structural formula (s-13)) which is a pyrazine derivative of the present invention and a phosphorescent compound (acetylacetonato) bis represented by the following structural formula (s-117) The ratio of [2,3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (hereinafter referred to as Ir (Fdpq) ₂ (acac)) in terms of mass ratio is DPhAPPr: Ir (Fdpq) ₂ (acac) = 1: 0.05 was co-evaporated to form a light emitting layer 7004. The film thickness was 30 nm. Accordingly, Ir (Fdpq) ₂ (acac) is dispersed in a layer made of DPhAPPr (structural formula (s-13)) which is a pyrazine derivative of the present invention.

Next, 10 nm of BAlq represented by the following structural formula (s-118) was deposited on the light-emitting layer 7004 to form an electron-transport layer 7005. Further, the ratio of Alq ₃ and lithium (Li) represented by the following structural formula (s-119) is set to Alq ₃ : Li = 1: 0.01 by mass ratio on the electron transport layer 7005. Co-evaporation was performed to form an electron injection layer 7006. The film thickness was 50 nm.

  Finally, 200 nm of aluminum was deposited as the second electrode 7007 over the electron injection layer 7006, whereby the light-emitting element 7010 of Example 7 was obtained. Note that the second electrode 7007 functioned as a cathode. Further, in the above-described vapor deposition process, the vapor deposition was all performed by a resistance heating method.

  The light emitting element 7010 of Example 7 was sealed in a nitrogen atmosphere glove box so that the light emitting element 7010 was not exposed to the atmosphere. Then, the operating characteristics of the light-emitting element 7010 of Example 7 were measured. The measurement was performed at room temperature (atmosphere kept at 25 ° C.).

28 shows current density-luminance characteristics and FIG. 29 shows voltage-luminance characteristics of the light-emitting element 7010 of Example 7. In FIG. In the light-emitting element 7010 of Example 7, when a voltage of 7.2 V was applied, a current flowed at a current density of 23.4 mA / cm ² , and light was emitted with a luminance of 843 cd / m ² . Further, the CIE chromaticity coordinates at this time were (x = 0.70, y = 0.29), and showed deep red light emission. Note that the peak wavelength of the emission spectrum was 640 nm, and light emission from Ir (Fdpq) ₂ (acac), which is a guest material, was obtained.

  In addition, FIG. 30 shows luminance-current efficiency characteristics of the light-emitting element 7010. FIG. 31 is obtained by converting the vertical axis of FIG. 30 into external quantum efficiency. As can be seen from FIGS. 30 and 31, the current efficiency was 8.63 cd / A at the maximum, and the external quantum efficiency at this time was 17.0%, indicating a very high luminous efficiency.

  From the above, it can be seen that a light-emitting element with extremely high light emission efficiency can be obtained by using the pyrazine derivative of the present invention as a host material of a light-emitting layer and using a phosphorescent compound as a guest material. It was.

  In Example 8, a light-emitting element having a different structure from that shown in Example 7 will be described. In addition, since it is the same structure as Example 7 except the electron carrying layer 8005, description is abbreviate | omitted. The element structure is shown in FIG.

In this example, Alq ₃ was used for the electron transport layer 8005 in place of BAlq used in Example 7. Other configurations are the same as those in the seventh embodiment.

FIG. 33 shows the current density-luminance characteristics and FIG. 34 shows the voltage-luminance characteristics of the light-emitting element 8010 of Example 8. In the light-emitting element 8010 of Example 8, when a voltage of 6.4 V was applied, a current flowed at a current density of 25.5 mA / cm ² , and light was emitted with a luminance of 927 cd / m ² . In addition, the CIE chromaticity coordinates at this time are (x = 0.68, y = 0.31), indicating deep red light emission. Note that the peak wavelength of the emission spectrum was 640 nm, and light emission from Ir (Fdpq) ₂ (acac), which is a guest material, was obtained.

  In addition, FIG. 35 shows luminance-current efficiency characteristics of the light-emitting element 8010 of the eighth embodiment. FIG. 36 is obtained by converting the vertical axis of FIG. 35 into external quantum efficiency. As can be seen from FIGS. 35 and 36, the maximum current efficiency was 6.16 cd / A, and the external quantum efficiency at this time was 11.7%, indicating a high luminous efficiency.

From the above, a light-emitting element with extremely high emission efficiency can be obtained by using the pyrazine derivative of the present invention as a host material for the light-emitting layer 7004 and using a phosphorescent compound as a guest material to produce a light-emitting element. all right. In this embodiment, Alq ₃ is used as the electron transport layer 8005 provided in contact with the light emitting layer 7004. Alq ₃ is generally known as a quencher that quenches the light emission of the phosphorescent compound. However, in this example, a light emitting element with high light emission efficiency can be achieved even though the electron transport layer 8005 made of Alq ₃ is in contact with the light emitting layer 7004. This is considered because the pyrazine derivative of the present invention has a bipolar property of carrying not only holes but also electrons.

(Synthesis Example 7)
As an example of the pyrazine derivative of the present invention, a compound represented by the structural formula (s-14), 2,3-bis [4- (N, N-diphenylamino) phenyl] 5,6-diphenylpyrazine (hereinafter referred to as DPhAPPPr) Will be described.

[Step 1: Method for synthesizing 2,3-bis (4-bromophenyl) -5,6-diphenylpyrazine (hereinafter referred to as PPPr)]
4,4′-Dibromobenzyl (3.0 g, 8.1 mmol) and meso-diphenylethylenediamine (1.8 g, 8.1 mmol) were placed in a 300 mL three-necked flask, ethanol (100 mL) was added, and the mixture was heated and stirred at 80 ° C. for 5 hours. And reacted. After the reaction, the reaction solution was concentrated, 2.3 g of manganese dioxide and 100 mL of chloroform were added, and the mixture was further reacted by heating and stirring at 80 ° C. for 1 hour. After the reaction, the reaction solution was washed with water, the aqueous layer and the organic layer were separated, and the organic layer was suction filtered through celite. The filtrate was concentrated, and the resulting solid was washed with a mixed solvent of chloroform and hexane to obtain 1.6 g of a powdery white solid of PPPr in a yield of 37% (Synthesis scheme (l-1)).

[Step 2: Method for synthesizing DPhAPPPr]
PPPr 3.2 g (5.9 mmol), DPhA 2.0 g (12 mmol), sodium-tert-butoxide 1.5 g (16 mmol) were placed in a 200 mL three-necked flask, and the inside of the flask was purged with nitrogen, followed by toluene 30 mL, tri-tert- 0.1 mL of a 10 wt% hexane solution of butylphosphine and 0.1 g (0.2 mmol) of bis (dibenzylideneacetone) palladium (0) were added, and this mixture was heated and stirred at 120 ° C. for 8 hours to be reacted. After the reaction, chloroform was added to the reaction mixture to dissolve the precipitate, and suction filtration was performed through Florisil, Celite, and alumina. The filtrate was washed with water, dried over magnesium sulfate, and suction filtered. The filtrate was concentrated, and the obtained solid was washed with a mixed solvent of toluene and methanol and then recrystallized with chloroform and methanol to obtain 1.8 g of a yellow powdery solid in a yield of 42%.

  The resulting yellow solid was purified by sublimation by the train sublimation method. The sublimation purification was performed at 294 ° C. for 15 hours under a reduced pressure of 7 Pa with an argon flow rate of 3 mL / min. When the amount of the yellow solid obtained previously was 1.8 g, 1.3 g of a target DPhAPPPr yellow solid was obtained in a yield of 72% (Synthesis scheme (1-2)).

The analysis result of the obtained DPhAPPPr by the proton nuclear magnetic resonance method ( ¹ H-NMR) is shown below. TMS was used as a reference material.
¹ H-NMR (300 MHz, CDCl ₃ ); δ = 6.95-7.18 (m, 16H), δ = 7.22-7.40 (m, 14H), δ = 7.57 (d, J = 8.3, 4H), δ = 7.60-7.68 (m, 4H)

In addition, FIGS. 37A and 37B show ¹ H-NMR charts of DPhAPPPr. Note that FIG. 37B is an enlarged view of the range of 6.5 ppm to 8.0 ppm in the chart of FIG.

  Further, FIG. 38 shows an absorption spectrum and an emission spectrum in a state where DPhAPPPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 38, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 38A is an absorption spectrum, and the spectrum shown in FIG. 38B is an emission spectrum (excitation wavelength 371 nm).

(Synthesis Example 8)
As an example of the pyrazine derivative of the present invention, a compound represented by the structural formula (s-52), 2,3-bis (4- {N- [4- (carbazol-9-yl) phenyl] -N-phenylamino, } Phenyl) -5,6-diphenylpyrazine (hereinafter referred to as YGAPPPPr) will be described.

  1.6 g (3.0 mmol) of PPPr, 2.0 g (6.0 mmol) of YGA, and 1.1 g (11 mmol) of sodium-tert-butoxide were placed in a 100 mL three-necked flask, and the inside of the flask was purged with nitrogen. 0.1 mL of a 10 wt% hexane solution of tert-butylphosphine was added, and the atmosphere in the flask was replaced with nitrogen again. Further, 0.1 g (0.2 mmol) of bis (dibenzylideneacetone) palladium (0) was added, and this mixture was heated and stirred at 80 ° C. for 5 hours to be reacted. After the reaction, toluene was added to the reaction mixture to dissolve the precipitate, and suction filtration was performed through Celite, Florisil, and alumina. The filtrate was washed with water, dried over magnesium sulfate, and suction filtered. The solid obtained by concentrating the filtrate was dissolved in toluene and purified by silica column chromatography. Column purification was performed by first using a mixed solvent of toluene: hexane = 1: 1 as a developing solvent, and then using toluene as a developing solvent. After column purification, the obtained solution was concentrated and the precipitated solid was recrystallized with chloroform and hexane to obtain 1.0 g of a powdery yellow solid in a yield of 16% (synthesis scheme (m-1 )).

The analysis result of the obtained YGAPPPPr by the proton nuclear magnetic resonance method ( ¹ H-NMR) is shown below. TMS was used as a reference material.
¹ H-NMR (300 MHz, CDCl ₃ ): δ = 7.00-7.10 (m, 2H), δ = 7.16 (d, J = 8.8, 4H), δ = 7.21-7 .47 (m, 34H), δ = 7.62-7.77 (m, 8H), δ = 8.13 (d, J = 7.3, 4H)

In addition, ¹ H-NMR charts of YGAPPPPr are shown in FIGS. Note that FIG. 39B is an enlarged view of the range of 6.5 ppm to 8.5 ppm in the chart of FIG.

  In addition, FIG. 40 shows an absorption spectrum and an emission spectrum in a state where YGAPPPPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 40, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). The spectrum shown in FIG. 40A is an absorption spectrum, and the spectrum shown in FIG. 40B is an emission spectrum (excitation wavelength 371 nm).

  In this example, DPhAPPPr (structural formula (s-14)), which is an example of the pyrazine derivative of the present invention synthesized in Synthesis Example 7 of Example 9, was used as the host material of the light-emitting layer, and a phosphorescent compound was used as the guest material. The example of the light emitting element used as is specifically illustrated. The element structure is shown in FIG. In addition, since it is the same structure as Example 7 except the light emitting layer 9004, description is abbreviate | omitted.

In this example, the light-emitting layer 9004 is formed using DPhAPPPr (structural formula (s-14)) which is a pyrazine derivative and the phosphorescent compound (acetylacetonato) bis [2, represented by the structural formula (s-117). The ratio of 3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (hereinafter referred to as Ir (Fdpq) ₂ (acac)) in terms of mass ratio is DPhAPPPr: Ir (Fdpq) ₂ (acac) = 1: It was formed by co-evaporation to be 0.07. The film thickness was 30 nm. Accordingly, Ir (Fdpq) ₂ (acac) is in a state of being dispersed in a layer made of DPhAPPPr (structural formula (s-14)) which is a pyrazine derivative of the present invention. Other configurations are the same as those in the seventh embodiment.

FIG. 41 shows the current density-luminance characteristics of the light emitting element 9010 of this example, FIG. 42 shows the voltage-luminance characteristics, FIG. 43 shows the luminance-current efficiency characteristics, and FIG. 44 shows the emission spectrum. In the light-emitting element 9010 of this example, when a voltage of 8.2 V was applied, current flowed at a current density of 34.1 mA / cm ² , and light was emitted with a luminance of 1100 cd / m ² . The current efficiency at this time was 3.1 cd / A. Further, the emission spectrum had a peak at 647 nm, and red light emission derived from Ir (Fdpq) ₂ (acac) which was a guest material was obtained. The CIE chromaticity coordinates at 1100 cd / m ² were (x, y) = (0.71, 0.29), and red light emission with very high color purity was obtained.

  From the above, it can be seen that a light-emitting element with extremely high light emission efficiency can be obtained by using the pyrazine derivative of the present invention as a host material of a light-emitting layer and using a phosphorescent compound as a guest material. It was.

  In this example, YGAPPPPr (structural formula (s-52)) which is an example of the pyrazine derivative of the present invention synthesized in Synthesis Example 8 of Example 10 was used as the host material of the light-emitting layer, and the phosphorescent compound was used as the guest material. The example of the light emitting element used as is specifically illustrated. The element structure is shown in FIG. In addition, since it is the same structure as Example 7 except the light emitting layer 5004, description is abbreviate | omitted.

In this example, the light-emitting layer 5004 includes a pyrazine derivative YGAPPPPr (structural formula (s-52)) and a phosphorescent compound (acetylacetonato) bis [2, represented by the structural formula (s-117). 3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (hereinafter referred to as Ir (Fdpq) ₂ (acac)), the mass ratio of YGAPPPPr: Ir (Fdpq) ₂ (acac) = 1: It was formed by co-evaporation to be 0.07. The film thickness was 30 nm. Accordingly, Ir (Fdpq) ₂ (acac) is in a state of being dispersed in a layer made of YGAPPPPr (structural formula (s-52)) which is a pyrazine derivative of the present invention. Other configurations are the same as those in the seventh embodiment.

FIG. 45 shows the current density-luminance characteristics of the light-emitting element 5010 of this example, FIG. 46 shows the voltage-luminance characteristics, FIG. 47 shows the luminance-current efficiency characteristics, and FIG. 48 shows the emission spectrum. In the light-emitting element 5010 of this example, when a voltage of 8.0 V was applied, a current flowed at a current density of 36.4 mA / cm2, and light was emitted with a luminance of 1100 cd / m2. The current efficiency at this time was 3.1 cd / A. Further, the emission spectrum had a peak at 650 nm, and red emission derived from Ir (Fdpq) 2 (acac) which is a guest material was obtained. The CIE chromaticity coordinates at 1100 cd / m ² were (x, y) = (0.71, 0.29), and red light emission with very high color purity was obtained.

  From the above, it can be seen that a light-emitting element with extremely high light emission efficiency can be obtained by using the pyrazine derivative of the present invention as a host material of a light-emitting layer and using a phosphorescent compound as a guest material. It was.

(Synthesis Example 10)
As an example of the pyrazine derivative of the present invention, a compound represented by the structural formula (s-88), 2- (4- {N- [4- (carbazol-9-yl) phenyl] -N-phenylamino} phenyl) A method for synthesizing -3,5,6-triphenylpyrazine (hereinafter referred to as YGA1PPr) will be described.

[Step 1: Method for synthesizing 2- (4-bromophenyl) -3,5,6-triphenylpyrazine (hereinafter referred to as 1 PPPr)]
(1) Synthesis of 1- (4-bromophenyl) -2-phenylacetylene.
28.3 g (0.10 mol) of p-bromoiodobenzene, 10.2 g (0.10 mol) of phenylacetylene, 0.70 g (1.0 mmol) of bis (triphenylphosphine) palladium (II) dichloride, copper iodide (I ) 0.19 g (1.0 mmol) was placed in a 1000 mL three-necked flask, and the atmosphere in the flask was replaced with nitrogen. Then, 350 mL of tetrahydrofuran and 18 mL of triethylamine were added, and the mixture was stirred at room temperature for 20 hours to be reacted. After the reaction, the reaction solution was washed with a 3 wt% hydrochloric acid aqueous solution, and then the organic layer and the aqueous layer were separated. After the aqueous layer was extracted with ethyl acetate, the extract and the organic layer were combined and washed with an aqueous sodium carbonate solution and saturated brine in that order, and the organic layer was dried over magnesium sulfate. The mixture of the organic layer and magnesium sulfate was filtered through Celite, Florisil, and alumina, and the filtrate was concentrated. The solid obtained was washed with hexane, and the target product 1- (4-bromophenyl) -2-phenyl was obtained. 19 g of acetylene solid was obtained in a yield of 74% (Synthesis scheme (n-1)).

(2) Synthesis of 4-bromobenzyl.
19 g (74 mmol) of 1- (4-bromophenyl) -2-phenylacetylene, 9.4 g (37 mmol) of iodine, and 200 mL of dimethyl sulfoxide were put into a 500 mL three-necked flask and stirred at 155 ° C. for 4 hours to be reacted. After the reaction, the reaction mixture was cooled, 3 wt% aqueous sodium thiosulfate was added, and the mixture was stirred for 1 hour at room temperature. Ethyl acetate was added to the mixture, and the mixture was further washed with 1N dilute hydrochloric acid, aqueous sodium hydrogen carbonate solution and saturated brine, and then the organic layer and the aqueous layer were separated. The organic layer was dried with magnesium sulfate, and the mixture of the organic layer and magnesium sulfate was filtered. The filtrate was concentrated, and the obtained solid was washed with hexane in an ice bath to obtain 15 g of a target 4-bromobenzyl solid in 58% yield (Synthesis scheme (n-2)). .

(3) Synthesis of 1 PPPr.
4-Bromobenzyl (3.0 g, 1.0 mmol) and meso-diphenylethylenediamine (2.2 g, 1.0 mmol) were placed in a 500 mL three-necked flask, 100 mL of ethanol was added, and the mixture was heated and stirred at 80 ° C. for 5 hours. I let you. After the reaction, the reaction solution was concentrated, 1.1 g of manganese dioxide and 100 mL of chloroform were added, and the mixture was further heated and stirred at 80 ° C. for 1 hour to be reacted. After the reaction, the reaction solution was washed with water, and then the organic layer and the aqueous layer were separated. The organic layer was filtered through celite, the filtrate was concentrated, and the obtained solid was recrystallized with a mixed solvent of chloroform and hexane. Obtained at 45% (synthesis scheme (n-3)).

[Step 2: Method for synthesizing YGA1PPr]
1 PPPr (2.2 mmol), YGA 0.72 g (2.2 mmol) and sodium-tert-butoxide 0.3 g (3.1 mmol) were placed in a 100 mL three-necked flask, and the inside of the flask was purged with nitrogen. 0.10 mL of a 10 wt% hexane solution of tert-butylphosphine was added, the inside of the flask was again purged with nitrogen, 0.10 g (0.2 mmol) of bis (dibenzylideneacetone) palladium (0) was added, and the mixture was heated at 80 ° C. The mixture was heated and stirred for 5 hours to react. After the reaction, toluene was added to the reaction mixture, followed by filtration through celite, florisil, and alumina. After washing the filtrate with water, the organic layer and the aqueous layer were separated, and the organic layer was dried over magnesium sulfate and filtered. When the solid obtained by concentrating the filtrate was recrystallized with a mixed solvent of chloroform and hexane, 0.90 g of a powdery pale yellow solid of YGA1PPPr as a target substance was obtained in a yield of 58% (synthesis scheme ( n-4)).

The analysis result of YGA1PPr by the proton nuclear magnetic resonance method ( ¹ H-NMR) is shown below. TMS was used as a reference material.
¹ H-NMR (300 MHz, CDCl ₃ ): δ = 7.07-7.17 (m, 3H), δ = 7.19-7.51 (m, 23H), δ = 7.53-7.82. (M, 8H), δ = 8.14 (d, J = 7.3, 2H)

In addition, ¹ H-NMR charts of YGA1PPr are shown in FIGS. Note that FIG. 51B is an enlarged view of the range of 6.5 ppm to 8.5 ppm in the chart of FIG.

  In addition, FIG. 52 shows an absorption spectrum and an emission spectrum in a state where YGA1PPr is dissolved in a toluene solution. For the measurement, an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550) was used. In FIG. 52, the horizontal axis represents wavelength (nm) and the vertical axis represents intensity (arbitrary unit). In FIG. 52, the spectrum shown in (a) is an absorption spectrum. The spectrum shown in (b) is an emission spectrum (excitation wavelength: 376 nm).

FIG. 6 illustrates an example of a light-emitting element of the present invention. FIG. 6 illustrates an example of a light-emitting element of the present invention. FIG. 11 illustrates an example of a display device of the present invention. FIG. 6 is a top view illustrating an example of a pixel portion of a display device of the present invention. FIG. 6 is a circuit diagram illustrating an example of a pixel portion of a display device of the present invention. FIG. 11 illustrates an example of a display device of the present invention. FIG. 14 illustrates an example of a panel including a display device of the present invention. FIG. 14 illustrates an example of an electronic device of the invention. FIG. 14 illustrates an example of an electronic device of the invention. ¹ H-NMR chart of BBAPPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of BBAPPr. The figure which shows the measurement result by cyclic voltammetry (CV) of BBAPPr. ¹ H-NMR chart of BPhAPPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of BPhAPPr. The absorption spectrum and emission spectrum in the single film state of BPhAPPr. ¹ H-NMR chart of DPhAPPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of DPhAPPr. The absorption spectrum and emission spectrum in a single film state of DPhAPPr. ¹ H-NMR chart of DPAPPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of DPAPPr. ¹ H-NMR chart of PCAPPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of PCAPPr. The absorption spectrum and emission spectrum in the single film state of PCAPPr. ¹ H-NMR chart of YGAPPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of YGAPPr. The absorption spectrum and emission spectrum in a single film state of YGAPPr. FIG. 10 shows an example of a light-emitting element of Example 7. FIG. 10 shows current density-luminance characteristics of the light-emitting element of Example 7. FIG. 13 shows voltage-luminance characteristics of the light-emitting element of Example 7. FIG. 10 shows luminance-current efficiency characteristics of the light-emitting element of Example 7. FIG. 10 shows luminance vs. external quantum efficiency characteristics of the light-emitting element of Example 7. FIG. 10 shows an example of a light-emitting element of Example 8. FIG. 10 shows current density-luminance characteristics of the light-emitting element of Example 8. FIG. 10 shows voltage-luminance characteristics of the light-emitting element of Example 8. FIG. 10 shows luminance-current efficiency characteristics of the light-emitting element of Example 8. FIG. 11 shows luminance vs. external quantum efficiency characteristics of the light-emitting element of Example 8. ¹ H-NMR chart of DPhAPPPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of DPhAPPPr. ¹ H-NMR chart of YGAPPPPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of YGAPPPPr. FIG. 14 shows current density-luminance characteristics of the light-emitting element of Example 11. FIG. 16 shows voltage-luminance characteristics of the light-emitting element of Example 11. FIG. 25 shows luminance-current efficiency characteristics of the light-emitting elements of Example 11. 10 shows an emission spectrum of the light-emitting element of Example 11. FIG. 14 shows current density-luminance characteristics of the light-emitting element of Example 12. FIG. 14 shows voltage-luminance characteristics of the light-emitting element of Example 12. FIG. 16 shows luminance-current efficiency characteristics of the light-emitting element of Example 12; 10 shows an emission spectrum of the light-emitting element of Example 12. FIG. 16 shows an example of a light-emitting element of Example 11. FIG. 16 shows an example of a light-emitting element of Example 12. ¹ H-NMR chart of YGA1PPr. The absorption spectrum and emission spectrum in the state dissolved in the toluene solution of YGA1PPr.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Light emitting element 101 1st electrode 102 Hole injection layer 103 Hole transport layer 104 Light emitting layer 105 Electron transport layer 106 Electron injection layer 107 Second electrode 200 Light emitting element 204 Light emitting layer 300 Substrate 301 Base insulating film 302 Gate insulating film 304 Interlayer insulating film 305 Partition layer 306 Sealing material 307 Space 310 Transistor 311 Capacitor 320 Transistor 330 Transistor 340 Transistor 350 Light emitting element 351 First electrode 352 Layer 353 Second electrode 360 Sealing substrate 370 Pixel unit 380 Driver circuit unit 390 Terminal Part 391 terminal electrode 392 anisotropic conductive layer 393 FPC
504 Gate line 505 Source line 506 Current supply line 610 Printed wiring board 651 Substrate 652 First electrode 653 Partition layer 654 Layer 655 Second electrode 656 Driver circuit 658 Dotted line 659 Substrate 700 Panel 701 Pixel portion 703 Signal line driver circuit 704 FPC
710 Printed circuit board 711 Controller 712 CPU
713 Memory 714 Power supply circuit 715 Audio processing circuit 716 Transmission / reception circuit 717 Interface (I / F) unit 718 Antenna port 720 Control signal generation circuit 721 Decoder 722 Register 723 Operation circuit 724 RAM
725 interface 731 VRAM
732 DRAM
733 Flash memory 734 Input unit 743 Antenna 747 Microphone 748 Speaker 800 Display panel 801 Housing 803 Signal processing circuit 804 Microphone 805 Speaker 806 Case 807 Battery 808 Input unit 810 Printed circuit board 820 Module 1801 Main body 1802 Display unit 1804 Operation key 1805 Shutter 1821 Main body 1822 Housing 1823 Display unit 1824 Keyboard 1825 External connection port 1826 Pointing mouse 1841 Main body 1842 Housing 1843 Display unit A
1844 Display B
1845 Recording medium (DVD or the like) reading portion 1846 Operation key 1847 Speaker portion 1861 Housing 1862 Support base 1863 Display portion 1864 Speaker 1865 Video input terminal 303a Interlayer insulating film 5004 Light emitting layer 5010 Light emitting element 7000 Substrate 7001 First electrode 7002 Hole Injection layer 7003 Hole transport layer 7004 Light emitting layer 7005 Electron transport layer 7006 Electron injection layer 7007 Second electrode 7010 Light emitting element 702a Scan line driver circuit 702b Scan line driver circuit 8005 Electron transport layer 8010 Light emitting element 9004 Light emitting layer 9010 Light emitting element

Claims (13)

A pyrazine derivative represented by the general formula (g-1).

(In the formula, R ¹ , R ² , and R ^{3 each} represent a hydrogen atom, an alkyl group, or an aryl group. A represents a general formula (a-1), a general formula (a-2), a general formula ( a-3) or a substituent represented by the general formula (a-4), wherein R ⁴ represents an alkyl group or an aryl group, and R ⁵ , R ⁶ , and R ⁷ represent It represents any of a hydrogen atom, an alkyl group, or an aryl group, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ each represents an aryl group, and α represents an arylene group. A pyrazine derivative represented by the general formula (g-2).

(In the formula, R ¹ and R ^{2 each} represent a hydrogen atom, an alkyl group, or an aryl group. A represents a general formula (a-1), a general formula (a-2), or a general formula (a-3). Or R ⁴ represents an alkyl group or an aryl group, and R ⁵ , R ⁶ , and R ⁷ represent a hydrogen atom or an alkyl group. A group or an aryl group, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ each represents an aryl group, and α represents an arylene group.) A pyrazine derivative represented by the general formula (g-3).

(In the formula, R ¹ , R ² and R ^{3 each} represent a hydrogen atom, an alkyl group, or an aryl group. Ar ¹ and Ar ² are a phenyl group, a 1-naphthyl group, a 2-naphthyl group, 2- It represents any of a biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a 9,9-dimethylfluoren-2-yl group, and a spiro-9,9′-bifluoren-2-yl group.) A pyrazine derivative represented by the general formula (g-4).

(In the formula, R ¹ , R ² and R ^{3 each} represent a hydrogen atom, an alkyl group or an aryl group. Ar ³ , Ar ⁴ and Ar ⁵ represent an aryl group.) A pyrazine derivative represented by the general formula (g-6).

(In the formula, R ¹ , R ² , and R ^{3 each} represent a hydrogen atom, an alkyl group, or an aryl group. R ⁴ represents an alkyl group or an aryl group. Ar ⁶ represents a phenyl group, 1 -Naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9-dimethylfluoren-2-yl group, spiro-9,9'-bifluoren-2-yl group Represents either one.) A pyrazine derivative represented by the general formula (g-7).

(In the formula, R ¹ , R ² , and R ^{3 each} represent a hydrogen atom, an alkyl group, or an aryl group. R ⁶ and R ⁷ each represent a hydrogen atom, an alkyl group, or an aryl group. Ar ⁷ represents an aryl group.) A pyrazine derivative represented by the general formula (g-9).

(In the formula, R ¹ and R ^{2 each} represent a hydrogen atom, an alkyl group, or an aryl group. Ar ¹ and Ar ² represent a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenyl group, 3 -Represents any one of -biphenyl group, 4-biphenyl group, 9,9-dimethylfluoren-2-yl group, and spiro-9,9'-bifluoren-2-yl group.) A pyrazine derivative represented by the general formula (g-10).

(In the formula, R ¹ and R ^{2 each} represent a hydrogen atom, an alkyl group, or an aryl group. Ar ³ , Ar ⁴ , and Ar ⁵ each represent an aryl group.) A pyrazine derivative represented by the general formula (g-12).

(In the formula, R ¹ and R ^{2 each} represent a hydrogen atom, an alkyl group, or an aryl group. R ⁴ represents an alkyl group or an aryl group. Ar ⁶ represents a phenyl group, a 1-naphthyl group, 2 -It represents any of a naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 9,9-dimethylfluoren-2-yl group, and spiro-9,9'-bifluoren-2-yl group. ) A pyrazine derivative represented by the general formula (g-13).

(In the formula, R ¹ and R ^{2 each} represent a hydrogen atom, an alkyl group, or an aryl group. R ⁶ and R ⁷ each represent a hydrogen atom, an alkyl group, or an aryl group. Ar ⁷ represents an aryl group. Represents a group.)   A light-emitting element having the pyrazine derivative according to any one of claims 1 to 10 between a pair of electrodes.   The display apparatus which has the said light emitting element of Claim 11.   The electronic device which has the said light emitting element of Claim 11.