CN113845491A - Benzophenothiazine derivatives and process for their preparation - Google Patents

Abstract

The present invention relates to a new class of benzophenothiazine derivatives and a preparation method. In the present invention, benzophenothiazine is used as an electron-donating group, and an electron-accepting group is covalently bonded to the nitrogen atom of phenothiazine, and the general structural formula is shown in the following formula a or b:

The acceptor group in this material forms a twisted molecular framework with the benzophenothiazine unit, forming the separated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital arrangement (LUMO), so it has efficient intramolecular charge-transfer transitions, and the separated HOMO and LUMO orbitals favorably reduce ΔEST, resulting in efficient thermally activated delayed fluorescence. The structure is stable, the raw materials are common and easy to obtain, and the production cost is low. The benzophenothiazine derivatives of the present invention are used in organic electroluminescence devices and have high luminous efficiency.

Description

Benzophenothiazine derivatives and preparation method thereof

technical field

The invention belongs to the technical field of organic photoelectric functional materials, in particular to a class of benzophenothiazine derivatives and a preparation method.

Background technique

Organic light-emitting diodes (OLEDs) are devices that use organic materials to convert electrical energy into light. Organic light-emitting materials are the basic core material of flexible display technology. Flexible OLED is the basis for realizing curved display and even future flexible display. OLED has the characteristics of display self-luminescence, which makes its contrast ratio, black field performance, color gamut, response speed, and viewing angle all revolutionary compared with the current mainstream LED liquid crystal display on the market. As a new generation of display technology, OLED has a simple display structure. , The consumables are environmentally friendly, and the OLED display has the characteristics of flexibility and rollability, which is more convenient for transportation and installation, breaking through the limitation of size, and it is more likely to have the advantage of low-cost popularization after large-scale mass production.

Organic light-emitting materials are the core technology of organic electroluminescence, and are also the focus of research and competition in this field. At present, the light-emitting materials of organic light-emitting diodes are mainly phosphorescent materials, mainly represented by iridium complexes. Due to the scarcity and high price of precious metals (such as iridium, platinum, etc.) in metal complex phosphorescent materials, their further development and applications are greatly limited. Therefore, the design of a new generation of organic electroluminescent material molecules with low cost, high luminous efficiency and high exciton utilization rate is an important topic in the field of organic light emitting diodes in recent years.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a class of benzophenothiazine derivative delayed fluorescent materials with stable structure, common and readily available raw materials, low production cost, high fluorescence quantum efficiency, high thermal stability and charge transfer in the polymer and its preparation method.

For achieving the above object, the technical scheme adopted in the present invention is as follows:

In one aspect, a benzophenothiazine derivative, the general structural formula of which is shown in the following formula a or b:

选自以下结构式中的任一种：in,

is selected from any one of the following structural formulas:

On the other hand, the preparation method of the benzophenothiazine derivative represented by the aforementioned formula a or b comprises: using the benzophenothiazine as the electron donor unit, and the electron acceptor unit at the nitrogen atom of the phenothiazine Covalent bonding occurs on the electron acceptor unit selected from 4-bromobenzonitrile, (4-bromophenyl)[bis(2,4,6-trimethylphenyl)]borane, 5-bromophenyl -1,3-phthalonitrile and 2-4-bromophenyl-4,6-diphenyl-1,3,5-triazine.

Further, the electron donor unit is

Further, the preparation method of benzophenothiazine derivative shown in formula a, the synthetic route is as follows:

为以下结构式中的任一种：in,

is any of the following structural formulas:

Further, the preparation method of benzophenothiazine derivative shown in formula a, comprises the following steps:

The corresponding benzophenothiazine complex 1 was obtained by dissolving 2-aminobenzenethiol and 1-tetralone in dimethyl sulfoxide and reacting at 110 °C for 24 h after purification;

叔丁醇钠、三(二亚苄基丙酮)二钯、四氟硼酸三叔丁基膦溶解于甲苯中，在氮气保护下反应13h后分离提纯得到。The benzophenothiazine complex 1, compound

Sodium tert-butoxide, tris(dibenzylideneacetone)dipalladium and tri-tert-butylphosphine tetrafluoroborate were dissolved in toluene, reacted under nitrogen protection for 13h, and obtained by separation and purification.

Further, the preparation method of benzophenothiazine derivative shown in formula b, the synthetic route is as follows:

为以下结构式中的任一种：in,

is any of the following structural formulas:

Further, the preparation method of benzophenothiazine derivative shown in formula b, comprises the following steps:

Compound 1, sulfur and iodine mixture are heated to 180-185°C, and react at this temperature for 25 minutes to separate and purify to obtain the corresponding benzophenothiazine complex 2;

叔丁醇钠、三(二亚苄基丙酮)二钯，四氟硼酸三叔丁基膦溶解于甲苯中，在氮气保护下反应13h后分析提纯得到。The benzophenothiazine complex 2, compound

Sodium tert-butoxide, tris(dibenzylideneacetone)dipalladium, and tri-tert-butylphosphine tetrafluoroborate were dissolved in toluene, reacted for 13h under nitrogen protection, and obtained by analysis and purification.

Beneficial technical effect achieved by the present invention:

The benzophenothiazine derivatives of the present invention use phenothiazine as an electron donor, which can inhibit the close packing between molecules and improve the fluorescence performance. Bonded with strong electron acceptors such as triarylboron and cyanobenzene, it can exert a strong LUMO localization effect, improve intramolecular charge transfer, and have high luminous efficiency. The introduction of benzene ring can improve plane conjugation and further broaden the spectral response range. Emission redshift. In addition, the present invention has the advantages of stable structure, common and readily available raw materials, low production cost and high thermal stability.

Description of drawings

1 is a schematic diagram of the absorption spectrum of the benzophenothiazine derivative prepared in Example 3 of the present invention;

2 is a schematic diagram of the absorption spectrum of the benzophenothiazine derivative prepared in Example 4 of the present invention;

Figure 3 is a schematic diagram of the emission spectrum of the benzophenothiazine derivative prepared in Example 3 of the present invention;

Figure 4 is a schematic diagram of the emission spectrum of the benzophenothiazine derivative prepared in Example 4 of the present invention;

Fig. 5 TGA spectrum of the benzophenothiazine derivative intermediate prepared in Example 4 of the present invention.

Fig. 6 TGA spectrum of the benzophenothiazine derivative prepared in Example 4 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and cannot be used to limit the protection scope of the present invention.

Principle of the present invention: The nitrogen and sulfur atoms in the molecule of the benzophenothiazine complex are electron-rich atoms, so the phenothiazine group exhibits a good electron donating ability. The heteroatom in the group presents sp ³ hybridization, which makes the six-membered ring form a dihedral angle of 150°, so that the phenothiazine molecule has a unique "butterfly-shaped" spatial structure, which makes the molecule retain a certain rigidity and flexibility. This structure can also inhibit the close packing between molecules and improve the fluorescence performance. Benzophenothiazine further improves the planar conjugation and broadens the spectral range. The electron acceptor group is covalently bonded to the benzophenothiazine group to form a twisted molecular skeleton, resulting in the separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital arrangement (LUMO), thus possessing highly efficient molecular The internal charge transfer transition, and the separated HOMO and LUMO orbitals are beneficial to reduce ΔE _ST , resulting in efficient thermally activated delayed fluorescence for application in the field of organic electroluminescence.

Specific examples are given below:

If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

Example 1:

The synthetic route is as follows:

A mixed solution of 2-aminobenzenethiol (0.75 g, 6 mmol) and 1-tetralone (0.584 g, 4 mmol) in DMSO (16.0 mL) was stirred at 110° C. in air for 24 hours. Upon completion, the reaction mixture was diluted with ethyl acetate (64.0 mL) and filtered. The volatiles were removed in vacuo to give the crude product. Further separation and purification by silica gel column chromatography (EtOAc/petroleum ether) gave benzophenothiazine 1. Yield: 87%. ¹ H NMR (400MHz, Chloroform-d) δ9.58(s, 2H), 7.89-7.80(m, 2H), 7.76-7.69(m, 2H), 7.64(dd, J=7.4, 1.5Hz, 2H) ,7.53–7.42(m,4H),7.29(dd,J=7.4,0.5Hz,2H),7.19–7.15(m,1H),7.15–7.01(m,7H).

In a round-bottomed flask, add benzophenothiazine 1 (1.246g, 5mmol), 4-bromobenzonitrile (1.092g, 6mmol), sodium tert-butoxide (2.76g, 15mmol), tris(dibenzylideneacetone) Dipalladium (92 mg, 0.1 mmol), tri-tert-butylphosphine tetrafluoroborate (0.146 g, 0.5 mmol), 25 mL of toluene. Under the protection of nitrogen, the mixture was stirred to dissolve, heated to reflux, and the reaction was stopped after 13 h. It was extracted three times with dichloromethane and dried over anhydrous sodium sulfate. Column chromatography separation to obtain benzophenothiazine delayed fluorescence luminescent material 2. Yield: 80%. ¹ H NMR(400MHz, Chloroform-d)δ8.01-7.92(m,1H),7.81-7.72(m,1H),7.72-7.62(m,3H),7.57-7.46(m,2H),7.37- 7.30 (m, 3H), 7.29 (dd, J=7.3, 1.5Hz, 1H), 7.22 (td, J=7.4, 1.6Hz, 1H), 7.18–7.09 (m, 2H).

Example 2:

The synthetic route is as follows:

A mixed solution of 2-aminobenzenethiol (0.75 g, 6 mmol) and 1-tetralone (0.584 g, 4 mmol) in DMSO (16.0 mL) was stirred at 110° C. in air for 24 hours. Upon completion, the reaction mixture was diluted with ethyl acetate (64.0 mL) and filtered. The volatiles were removed in vacuo to give the crude product. Further separation and purification by silica gel column chromatography (EtOAc/petroleum ether) gave benzophenothiazine 1. Yield: 87%. ¹ H NMR (400MHz, Chloroform-d) δ9.58(s, 2H), 7.89-7.80(m, 2H), 7.76-7.69(m, 2H), 7.64(dd, J=7.4, 1.5Hz, 2H) ,7.53–7.42(m,4H),7.29(dd,J=7.4,0.5Hz,2H),7.19–7.15(m,1H),7.15–7.01(m,7H).

In a round bottom flask, add benzophenothiazine 1 (1.246g, 5mmol), (4-bromophenyl)[bis(2,4,6-trimethylphenyl)]borane (2.424g, 6mmol) , sodium tert-butoxide (2.76g, 15mmol), tris(dibenzylideneacetone)dipalladium (92mg, 0.1mmol), tri-tert-butylphosphine tetrafluoroborate (0.146g, 0.5mmol), 25mL of toluene. Under the protection of nitrogen, the mixture was stirred to dissolve, heated to reflux, and the reaction was stopped after 13 h. It was extracted three times with dichloromethane and dried over anhydrous sodium sulfate. Column chromatography separation to obtain benzophenothiazine delayed fluorescence luminescent material 2. Yield: 80%. ¹ H NMR(400MHz, Chloroform-d)δ7.97-7.90(m,1H),7.78(ddd,J=7.3,2.0,1.4Hz,1H),7.73-7.64(m,3H),7.59-7.46( m, 2H), 7.33–7.26 (m, 2H), 7.23–7.15 (m, 2H), 7.15–7.08 (m, 3H), 6.92 (s, 4H), 2.31 (d, J=0.7Hz, 6H) ,2.25(s,12H).

Example 3:

The synthetic route is as follows:

A mixed solution of 2-aminobenzenethiol (0.75 g, 6 mmol) and 1-tetralone (0.584 g, 4 mmol) in DMSO (16.0 mL) was stirred at 110° C. in air for 24 hours. Upon completion, the reaction mixture was diluted with ethyl acetate (64.0 mL) and filtered. The volatiles were removed in vacuo to give the crude product. Further separation and purification by silica gel column chromatography (EtOAc/petroleum ether) gave benzophenothiazine 1. Yield: 87%. ¹ H NMR (400MHz, Chloroform-d) δ9.58(s, 2H), 7.89-7.80(m, 2H), 7.76-7.69(m, 2H), 7.64(dd, J=7.4, 1.5Hz, 2H) ,7.53–7.42(m,4H),7.29(dd,J=7.4,0.5Hz,2H),7.19–7.15(m,1H),7.15–7.01(m,7H).

In a round-bottomed flask, add benzophenothiazine 1 (1.246g, 5mmol), 5-bromo-1,3-phthalonitrile (1.246g, 6mmol), sodium tert-butoxide (2.76g, 15mmol), tris( Dibenzylideneacetone) dipalladium (92 mg, 0.1 mmol), tri-tert-butylphosphine tetrafluoroborate (0.146 g, 0.5 mmol), 25 mL of toluene. Under the protection of nitrogen, the mixture was stirred to dissolve, heated to reflux, and the reaction was stopped after 13 h. It was extracted three times with dichloromethane and dried over anhydrous sodium sulfate. Column chromatography separation to obtain benzophenothiazine delayed fluorescence luminescent material 2. Yield: 80%. ¹ H NMR(400MHz, Chloroform-d)δ7.95-7.88(m,1H),7.86(t,J=1.4Hz,1H),7.81-7.72(m,3H),7.68(dd,J=7.6, 1.4Hz, 1H), 7.56–7.45 (m, 2H), 7.36–7.26 (m, 2H), 7.26–7.20 (m, 1H), 7.20–7.13 (m, 1H), 7.09 (td, J=7.3, 1.8Hz, 1H).

Example 4:

The synthetic route is as follows:

A mixed solution of 2-aminobenzenethiol (0.75 g, 6 mmol) and 1-tetralone (0.584 g, 4 mmol) in DMSO (16.0 mL) was stirred at 110° C. in air for 24 hours. Upon completion, the reaction mixture was diluted with ethyl acetate (64.0 mL) and filtered. The volatiles were removed in vacuo to give the crude product. Further separation and purification by silica gel column chromatography (EtOAc/petroleum ether) gave benzophenothiazine 1. Yield: 87%. ¹ H NMR (400MHz, Chloroform-d) δ9.58(s, 2H), 7.89-7.80(m, 2H), 7.76-7.69(m, 2H), 7.64(dd, J=7.4, 1.5Hz, 2H) ,7.53–7.42(m,4H),7.29(dd,J=7.4,0.5Hz,2H),7.19–7.15(m,1H),7.15–7.01(m,7H).

In a round bottom flask, add benzophenothiazine 1 (1.246g, 5mmol), 2-4-bromophenyl-4,6-diphenyl-1,3,5-triazine (2.329g, 6mmol), Sodium tert-butoxide (2.76g, 15mmol), tris(dibenzylideneacetone)dipalladium (92mg, 0.1mmol), tri-tert-butylphosphine tetrafluoroborate (0.146g, 0.5mmol), toluene 25mL. Under the protection of nitrogen, the mixture was stirred to dissolve, heated to reflux, and the reaction was stopped after 13 h. It was extracted three times with dichloromethane and dried over anhydrous sodium sulfate. Column chromatography separation to obtain benzophenothiazine delayed fluorescence luminescent material 2. Yield: 80%. ¹ H NMR (400MHz, Chloroform-d) δ 8.61-8.50 (m, 4H), 8.09-8.02 (m, 2H), 7.94 (dd, J=7.1, 1.7Hz, 1H), 7.78 (dt, J= 7.6, 1.7Hz, 1H), 7.69 (dd, J=7.5, 1.5Hz, 1H), 7.59–7.51 (m, 2H), 7.51–7.48 (m, 3H), 7.48–7.36 (m, 5H), 7.34 –7.26(m,2H),7.23–7.13(m,2H),7.07(ddd,J=7.5,6.7,2.4Hz,1H).

Example 5:

The synthetic route is as follows:

In a 250 mL round bottom flask, compound 1 (1.35 g, 5 mmol), sulfur (0.32 g, 5 mmol) and iodine (0.33 g, 1.3 mmol) were added. The reaction mixture was raised to 180-185°C and held at this temperature for 25 minutes, then cooled to room temperature. The dark reaction mass was dissolved in a small amount of acetone and enough petroleum ether was added to produce two layers. After separation of the layers, the dark solution was extracted several times with fresh warm petroleum ether and the petroleum ether layers were combined. After evaporation of the solvent, a yellow-brown crystalline solid was formed, which was crystallized from n-octane to give the benzophenothiazine complex 2. Yield; 70%. ¹ H NMR (400MHz, Chloroform-d)δ7.94-7.84(m,1H),7.76-7.66(m,2H),7.53-7.41(m,2H),7.34(dd,J=7.4,0.6Hz, 1H).

In a round-bottomed flask, add benzophenothiazine complex 2 (1.49g, 5mmol), 4-bromobenzonitrile (1.092g, 6mmol), sodium tert-butoxide (2.76g, 15mmol), tris(dibenzylidene) acetone) dipalladium (92 mg, 0.1 mmol), tri-tert-butylphosphine tetrafluoroborate (0.146 g, 0.5 mmol), 25 mL of toluene. Under the protection of nitrogen, the mixture was stirred to dissolve, heated to reflux, and the reaction was stopped after 13 h. It was extracted three times with dichloromethane and dried over anhydrous sodium sulfate. Column chromatography separation to obtain benzophenothiazine delayed fluorescence luminescent material 3. Yield: 80%. ¹ H NMR (400MHz, Chloroform-d)δ7.97-7.88(m,1H),7.80-7.73(m,1H),7.72-7.63(m,2H),7.57-7.46(m,2H),7.37- 7.29(m,2H).

Example 6:

The synthetic route is as follows:

In a 250 mL round bottom flask, compound 1 (1.35 g, 5 mmol), sulfur (0.32 g, 5 mmol) and iodine (0.33 g, 1.3 mmol) were added. The reaction mixture was raised to 180-185°C and held at this temperature for 25 minutes, then cooled to room temperature. The dark reaction mass was dissolved in a small amount of acetone and enough petroleum ether was added to produce two layers. After separation of the layers, the dark solution was extracted several times with fresh warm petroleum ether and the petroleum ether layers were combined. After evaporation of the solvent, a yellow-brown crystalline solid was formed, which was crystallized from n-octane to give the benzophenothiazine complex 2. Yield; 70%. ¹ H NMR (400MHz, Chloroform-d)δ7.94-7.84(m,1H),7.76-7.66(m,2H),7.53-7.41(m,2H),7.34(dd,J=7.4,0.6Hz, 1H).

In a round bottom flask, add benzophenothiazine complex 2 (1.49g, 5mmol), compound (4-bromophenyl)[bis(2,4,6-trimethylphenyl)]borane (2.424g) , 6mmol), sodium tert-butoxide (2.76g, 15mmol), tris(dibenzylideneacetone)dipalladium (92mg, 0.1mmol), tri-tert-butylphosphine tetrafluoroborate (0.146g, 0.5mmol), toluene 25mL . Under the protection of nitrogen, the mixture was stirred to dissolve, heated to reflux, and the reaction was stopped after 13 h. It was extracted three times with dichloromethane and dried over anhydrous sodium sulfate. Column chromatography separation to obtain benzophenothiazine delayed fluorescence luminescent material 3. Yield: 80%. ¹ H NMR (400 MHz, Chloroform-d) δ 7.94 (dd, J=7.3, 1.9 Hz, 1H), 7.78 (dt, J=7.1, 1.7 Hz, 1H), 7.73-7.64 (m, 2H), 7.58 –7.46(m,2H),7.27(dd,J=7.5,0.5Hz,1H),7.18–7.11(m,1H),6.91(s,2H),2.31(d,J=0.7Hz,3H), 2.25(s,6H).

Example 7:

The synthetic route is as follows:

In a 250 mL round bottom flask, compound 1 (1.35 g, 5 mmol), sulfur (0.32 g, 5 mmol) and iodine (0.33 g, 1.3 mmol) were added. The reaction mixture was raised to 180-185°C and held at this temperature for 25 minutes, then cooled to room temperature. The dark reaction mass was dissolved in a small amount of acetone and enough petroleum ether was added to produce two layers. After separation of the layers, the dark solution was extracted several times with fresh warm petroleum ether and the petroleum ether layers were combined. After evaporation of the solvent, a yellow-brown crystalline solid was formed, which was crystallized from n-octane to give the benzophenothiazine complex 2. Yield; 70%. ¹ H NMR (400MHz, Chloroform-d)δ7.94-7.84(m,1H),7.76-7.66(m,2H),7.53-7.41(m,2H),7.34(dd,J=7.4,0.6Hz, 1H).

Add benzophenothiazine complex 2 (1.49g, 5mmol), compound 5-bromo-1,3-phthalonitrile (1.246g, 6mmol), sodium tert-butoxide (2.76g, 15mmol) to a round bottom flask , tris(dibenzylideneacetone)dipalladium (92mg, 0.1mmol), tri-tert-butylphosphine tetrafluoroborate (0.146g, 0.5mmol), toluene 25mL. Under the protection of nitrogen, the mixture was stirred to dissolve, heated to reflux, and the reaction was stopped after 13 h. It was extracted three times with dichloromethane and dried over anhydrous sodium sulfate. Column chromatography separation to obtain benzophenothiazine delayed fluorescence luminescent material 3. Yield: 80%. ¹ H NMR(400MHz, Chloroform-d)δ7.95-7.86(m,4H),7.85(t,J=1.4Hz,2H),7.81-7.77(m,1H),7.77-7.68(m,11H) ,7.55–7.46(m,8H),7.39–7.32(m,4H).

Example 8:

The synthetic route is as follows:

In a 250 mL round bottom flask, compound 1 (1.35 g, 5 mmol), sulfur (0.32 g, 5 mmol) and iodine (0.33 g, 1.3 mmol) were added. The reaction mixture was raised to 180-185°C and held at this temperature for 25 minutes, then cooled to room temperature. The dark reaction mass was dissolved in a small amount of acetone and enough petroleum ether was added to produce two layers. After separation of the layers, the dark solution was extracted several times with fresh warm petroleum ether and the petroleum ether layers were combined. After evaporation of the solvent, a yellow-brown crystalline solid was formed, which was crystallized from n-octane to give the benzophenothiazine complex 2. Yield; 70%. ¹ H NMR (400MHz, Chloroform-d)δ7.94-7.84(m,1H),7.76-7.66(m,2H),7.53-7.41(m,2H),7.34(dd,J=7.4,0.6Hz, 1H).

In a round bottom flask, add benzophenothiazine complex 2 (1.49g, 5mmol), 2-4-bromophenyl-4,6-diphenyl-1,3,5-triazine (2.329g, 6mmol) , sodium tert-butoxide (2.76g, 15mmol), tris(dibenzylideneacetone)dipalladium (92mg, 0.1mmol), tri-tert-butylphosphine tetrafluoroborate (0.146g, 0.5mmol), 25mL of toluene. Under the protection of nitrogen, the mixture was stirred to dissolve, heated to reflux, and the reaction was stopped after 13 h. It was extracted three times with dichloromethane and dried over anhydrous sodium sulfate. Column chromatography separation to obtain benzophenothiazine delayed fluorescence luminescent material 3. Yield: 80%. ¹ H NMR (400MHz, Chloroform-d)δ8.60-8.51(m,2H),8.05-7.98(m,1H),7.96-7.86(m,1H),7.83-7.74(m,1H),7.68( dd, J=7.4, 1.5Hz, 1H), 7.56–7.42 (m, 5H), 7.40–7.33 (m, 1H), 7.27 (d, J=7.5Hz, 1H).

Material property testing

1. Spectral test:

The benzophenothiazine derivatives prepared in Example 3 and Example 4 were selected for spectral testing. The absorption spectrum and emission spectrum of the benzophenothiazine derivatives in Example 3 were shown in Figure 1 and Figure 3, respectively. The absorption spectrum and the emission spectrum of the benzophenothiazine derivative of Example 4 are shown in Fig. 2 and Fig. 4, respectively.

It can be seen from FIG. 3 and FIG. 4 that the benzophenothiazine derivatives synthesized in the present invention have high luminous efficiency and can be applied to organic electroluminescent devices.

2. TGA test:

The thermal weight loss temperature of each benzophenothiazine derivative prepared in Examples 1-8 of the present invention was tested, and the test results are shown in Table 1 below.

Note: The thermogravimetric temperature is the temperature at which 5% of the weight is lost in a nitrogen atmosphere.

Table 1

From the above data, it can be known that the benzophenothiazine derivatives synthesized by the present invention have excellent thermal stability and can meet the requirements for the use of organic electroluminescent materials.

The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention, and all technical solutions obtained by adopting equivalent replacement or equivalent transformation schemes all fall within the protection scope of the present invention.

Claims (7)

1. a benzophenothiazine derivative, is characterized in that, its general structural formula is shown in following formula a or b:

in,

is selected from any one of the following structural formulas:

2. the preparation method of a kind of benzophenothiazine derivative according to claim 1 is characterized in that, with benzophenothiazine as electron donor unit, and electron acceptor unit in the nitrogen atom of phenothiazine Covalent bonding occurs on the electron acceptor unit selected from 4-bromobenzonitrile, (4-bromophenyl)[bis(2,4,6-trimethylphenyl)]borane, 5-bromophenyl -1,3-phthalonitrile and 2-4-bromophenyl-4,6-diphenyl-1,3,5-triazine. 3. preparation method according to claim 2, is characterized in that, described electron donor unit is

4. the preparation method of benzophenothiazine derivative shown in formula a in claim 1, is characterized in that, synthetic route is as follows:

in,

is any of the following structural formulas:

5. preparation method according to claim 4, is characterized in that, comprises the following steps: The corresponding benzophenothiazine complex 1 was obtained by dissolving 2-aminobenzenethiol and 1-tetralone in dimethyl sulfoxide and reacting at 110 °C for 24 h after purification; The benzophenothiazine complex 1, compound

Sodium tert-butoxide, tris(dibenzylideneacetone)dipalladium and tri-tert-butylphosphine tetrafluoroborate were dissolved in toluene, reacted under nitrogen protection for 13h, and obtained by separation and purification. 6. the preparation method of benzophenothiazine derivative shown in formula b in claim 1, is characterized in that, synthetic route is as follows:

in,

is any of the following structural formulas:

7. preparation method according to claim 6, is characterized in that, comprises the following steps: Compound 1, sulfur and iodine mixture are heated to 180-185°C, and react at this temperature for 25 minutes to separate and purify to obtain the corresponding benzophenothiazine complex 2; The benzophenothiazine complex 2, compound

Sodium tert-butoxide, tris(dibenzylideneacetone)dipalladium, and tri-tert-butylphosphine tetrafluoroborate were dissolved in toluene, reacted for 13h under nitrogen protection, and obtained by analysis and purification.

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