Compound containing pyrazine-benzothiophene / indole, preparation method thereof and organic electroluminescent device
By synthesizing compounds containing pyrazine-benzothiophene/indole, the problems of complex molecular structure and wide emission spectrum of OLED red light were solved, achieving efficient red light emission and narrow-band light emission, improving the efficiency and lifespan of OLED devices, and making them suitable for ultra-high-definition displays.
Patent Information
- Application Number
- CN202510757165.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-09
- Publication Date
- 2025-11-18
AI Technical Summary
Existing OLED luminescent materials are inefficient, especially red light molecules which have complex structures and are difficult to synthesize, limiting their potential for commercial applications. Furthermore, traditional fluorescent materials have low luminescent efficiency, and TADF materials have a relaxed structure in the excited state, resulting in a broadened emission spectrum, which makes it difficult to meet the requirements of ultra-high resolution displays.
By using compounds containing pyrazine-benzothiophene/indole as electron-donating groups, a series of coupling reactions are used to synthesize the product, achieving spectral redshift and narrow bandgap emission, enhancing structural rigidity, and applying it to organic electroluminescent devices. The one-pot synthesis process simplifies the production process.
It achieves high-purity red light emission, improves device efficiency, breaks through the lifespan limitations of traditional fluorescent materials, is suitable for ultra-high-definition displays, has a simple synthesis route, high yield, and is suitable for large-scale industrial production.
Smart Images
Figure CN120965724A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electroluminescent materials technology, and more specifically, to a compound containing pyrazine-benzothiophene / indole, its preparation method, and an organic electroluminescent device. Background Technology
[0002] Research into the light-emitting principle of organic electroluminescent OLEDs began in 1987 when Eastman Kodak manufactured the first OLED bilayer device, marking the official start of OLED research. This achievement quickly attracted widespread attention and keen interest from researchers and industry, driving the vigorous development of OLED research and applications. After more than 30 years of development, OLED has achieved revolutionary progress in both basic research and practical applications. Today, almost all high-end smartphone models on the market are equipped with OLED displays. The applications of OLED are not limited to display technology; its self-emissive properties have also attracted the attention of lighting and light source manufacturers. For example, well-known lighting manufacturers such as Knight Kerr and Philips have begun investing in research and development and have successfully applied OLED technology to the lighting field. Therefore, among many organic electronic devices, OLED is undoubtedly the fastest-growing, most technologically mature, and has the broadest commercial application prospects.
[0003] Despite the significant advantages OLEDs have shown in display and lighting applications, their high manufacturing costs, insufficient efficiency of luminescent materials, and device stability remain major challenges. Achieving a technological breakthrough hinges on improving luminescent materials. Currently, commercially available OLEDs primarily utilize traditional fluorescent and phosphorescent materials. Fluorescent materials are renowned for their low cost and excellent device stability, but their luminescent efficiency is low, utilizing only 25% of singlet excitons. Thermally activated delayed fluorescence (TADF) materials, a third emerging luminescent material in the last decade, can convert triplet excitons into singlet excitons through antisystem crossing, theoretically achieving 100% internal quantum efficiency. Furthermore, TADF materials are free of precious metals, resulting in lower costs and combining high efficiency with low cost. However, most TADF emitters suffer severe structural relaxation in the excited state due to their electron donor-acceptor (DA) structure, leading to a broadened emission spectrum and a large full width at half maximum (FWHM). To meet the BT.2020 wide color gamut standard, multiple resonance (MR) TADF materials suitable for ultra-high resolution displays have emerged, achieving narrower emission spectra and higher color accuracy. However, due to the structural characteristics of MR-TADF materials, the number of molecules capable of emitting red light is currently far fewer than that emitting blue and green light, which limits the potential of MR-TADF molecules in commercial applications. Furthermore, many existing red light molecules have complex structures, are difficult to synthesize, and have low yields, which also restricts their widespread application. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a compound containing pyrazine-benzothiophene / indole, its preparation method, and an organic electroluminescent device. The pyrazine-benzothiophene / indole compound uses pyrazine-benzothiophene / indole as an electron-donating group, which can red-shift the spectrum and effectively achieve red light emission. Moreover, its synthetic route is simple and the yield is high. The organic electroluminescent device has the advantages of narrow half-maximum width and high external quantum efficiency.
[0005] The specific technical solution of the present invention is as follows: In a first aspect, the present invention provides a compound containing pyrazine-benzothiophene / indole, having a structure as shown in Formula I: ; Wherein, the X group is selected from at least one of S, O, N, and Se. When the X group is N, a benzene ring is used to replace the nitrogen-hydrogen bond, and the N atom is protected by the structure of formula (II). ; The R group is selected from at least one of hydrogen, alkyl, fluorine, chlorine, bromine, iodine, nitrogen, cyano and aromatic ring, wherein the aromatic ring is selected from any one of the following: an aromatic ring composed of carbon and hydrogen, an aromatic heterocycle composed of carbon, nitrogen and hydrogen, an aromatic heterocycle composed of carbon and oxygen hydrogen, an aromatic heterocycle composed of carbon, sulfur and hydrogen and an aromatic heterocycle composed of carbon, nitrogen, sulfur and hydrogen.
[0006] In one possible embodiment, the starting material for synthesizing the pyrazine-benzothiophene / indole compound comprises a diketone compound containing an R group and an X group, the diketone compound having any of the structures RX1-RX40: .
[0007] In one possible implementation, the pyrazine-benzothiophene / indole compound is any one of BN1-BN40: .
[0008] Secondly, the present invention also provides a method for preparing the above-mentioned pyrazine-benzothiophene / indole-containing compound, comprising the following steps: S1. Under a protective atmosphere, 3,5-difluoro-1,2-diamine undergoes a coupling reaction with a diketone compound containing R and X groups under weakly acidic conditions to yield a fluoro-benzothiophene / indole-containing quinoxaline, the structure of which is shown in Formula III: ; S2. Under a protective atmosphere, the fluoro-benzothiophene / indole-containing quinoxaline described in step S1 is coupled with iodine in a solution containing diisopropylaminolithium and tetrahydrofuran to obtain an iodine-fluoro-benzothiophene / indole-containing quinoxaline, the structure of which is shown in Formula IV: ; S3. Under a protective atmosphere, the iodine-fluorine-benzothiophene / indole-containing quinoxaline described in step S2 is coupled with tert-butylcarbazole in N,N-dimethylformamide to obtain quinoxaline containing di-tert-butylcarbazole-iodine-fluorine-benzothiophene / indole, the structure of which is shown in Formula V. ; S4. Under a protective atmosphere, the quinoxaline containing di-tert-butylcarbazole-iodine-fluorine-benzothiophene / indole described in step S3 is coupled with BBr3 in a solution containing n-butyllithium, N,N-diisopropylethylamine and trimethylbenzene to obtain a compound containing pyrazine-benzothiophene / indole.
[0009] In one possible implementation, the molar ratio of the 3,5-difluoro-1,2-diamine to the diketone compound containing R and X groups in step S1 is 3:2. Limiting the molar ratio of the 3,5-difluoro-1,2-diamine to the diketone compound containing R and X groups to 3:2 is beneficial for improving the conversion rate of the product.
[0010] In one possible implementation, the molar ratio of the fluorinated-benzothiophene / indole quinoxaline to the iodine in step S2 is 1:3, and the molar ratio of the fluorinated-benzothiophene / indole quinoxaline to the diisopropylaminolithium is 1:2. In one possible implementation, the molar ratio of the iodine-fluorinated-benzothiophene / indole quinoxaline to the tert-butylcarbazole in step S3 is 1:2.2.
[0011] In one possible implementation, the molar ratio of the quinoxaline containing di-tert-butylcarbazole-iodine-fluorine-benzothiophene / indole in step S4 to the BBr3 is 1:2, the molar ratio of the BBr3 to the n-butyllithium is 4:3, and the molar ratio of the BBr3 to the N,N-diisopropylethylamine is 1:1.
[0012] Thirdly, the present invention also provides an organic electroluminescent device, wherein the light-emitting layer material of the organic electroluminescent device comprises the above-mentioned compound containing pyrazine-benzothiophene / indole.
[0013] In one possible embodiment, the organic electroluminescent device comprises, from bottom to top, a transparent substrate, an ITO conductive glass anode, a hole injection layer HATCN, hole transport layers TAPC and TCTA, a light-emitting layer, an electron transport layer TmPyPb, an electron injection layer LiF, and a cathode layer Al. The light-emitting layer is composed of the aforementioned pyrazine-benzothiophene / indole compound as a dopant guest material, and DMIC-TRz and PO-O1 as host materials. The mass percentage of the dopant guest material in the light-emitting layer is 1-3%, the mass percentage of DMIC-TRz is 85-90%, and the mass percentage of PO-O1 is 8-12%. The structural formulas of HATCN, TAPC, TCTA, DMIC-TRz, PO-O1, and TmPyPb are shown below: .
[0014] Based on common knowledge in the field, the above-described embodiments can be combined arbitrarily.
[0015] The reagents and raw materials used in this invention are all commercially available.
[0016] The positive and progressive effects of this invention are as follows: The pyrazine-benzothiophene / indole compounds provided in this invention enhance structural rigidity while achieving narrow-band emission. The strong electron-donating groups pyrazine-benzothiophene / indole cause a redshift in the molecular emission spectrum and narrow the band gap. When applied to organic electroluminescent devices, they can achieve high-purity red light emission and ultra-high-definition display. Furthermore, due to the effect of heavy atoms such as S, they can alleviate the efficiency roll-off of the device, breaking through the lifespan limit of traditional fluorescent materials and exhibiting high fluorescence quantum yield, which is beneficial for achieving high device efficiency. The preparation method of the pyrazine-benzothiophene / indole compounds involves a one-pot coupling reaction of quinoxaline containing pyrazine-benzothiophene / indole with BBr3 to obtain the pyrazine-benzothiophene / indole compounds. This method has the advantages of simple synthetic route, mild reaction conditions, and strong adaptability to reactants, making it convenient for large-scale industrial production. Attached Figure Description
[0017] Figure 1 The UV absorption and fluorescence emission spectra of BN-BTP prepared in Example 1 are shown.
[0018] Figure 2 The UV absorption and fluorescence emission spectra of the BN-IDP prepared in Example 2 are shown.
[0019] Figure 3 The graphs show the current density-voltage-brightness relationship of the organic electroluminescent devices in Examples 41 and 42.
[0020] Figure 4 The images show the emission spectra of the organic electroluminescent devices in Examples 41 and 42.
[0021] Figure 5 The graphs show the external quantum efficiency-luminescence relationship of the organic electroluminescent devices in Examples 41 and 42. Detailed Implementation
[0022] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the claims of the present invention.
[0023] It should be noted that the endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0024] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.
[0025] The specific technical solution of the present invention is as follows: In a first aspect, the present invention provides a compound containing pyrazine-benzothiophene / indole, having a structure as shown in Formula I: ; Wherein, the X group is selected from at least one of S, O, N, and Se. When the X group is N, a benzene ring is used to replace the nitrogen-hydrogen bond, and the N atom is protected by the structure of formula (II). ; The R group is selected from at least one of hydrogen, alkyl, fluorine, chlorine, bromine, iodine, nitrogen, cyano, and aromatic ring, wherein the aromatic ring is selected from any one of the following: an aromatic ring composed of carbon and hydrogen, an aromatic heterocycle composed of carbon, nitrogen, and hydrogen, an aromatic heterocycle composed of carbon, oxygen, and hydrogen, an aromatic heterocycle composed of carbon, sulfur, and hydrogen, and an aromatic heterocycle composed of carbon, nitrogen, sulfur, and hydrogen.
[0026] The pyrazine-benzothiophene / indole compounds provided by this invention embed pyrazine-benzothiophene / indole units as strong electron donors on the basis of a traditional MR-TADF core. Their interaction with the acceptor unit causes a redshift in the molecular emission spectrum. Furthermore, the overall conjugated system of the pyrazine-benzothiophene / indole compounds further promotes this redshift, effectively achieving red light emission and narrowing the band gap for narrow-band emission. The pyrazine-benzothiophene / indole structure also increases intramolecular spin-orbit coupling, increasing the rate of cross-linking between molecular antigap structures, further improving the electron transport performance and luminescence efficiency of the pyrazine-benzothiophene / indole compounds. The tert-butyl group in the pyrazine-benzothiophene / indole compounds increases steric hindrance during intermolecular stacking, reduces π-π stacking, and avoids aggregation-induced quenching effects, which is beneficial for improving their luminescence efficiency.
[0027] In one possible embodiment, the starting material for synthesizing the pyrazine-benzothiophene / indole compound comprises a diketone compound containing an R group and an X group, the diketone compound having any of the structures RX1-RX40: .
[0028] When preparing compounds containing pyrazine-benzothiophene / indole using the above reactants, the diketone compounds exhibit high regioselectivity and chemoselectivity due to their high reactivity and specific reaction sites. This selectivity helps reduce side reactions, simplify product purification steps, and obtain intermediates with high reaction yields and high purity.
[0029] In one possible implementation, the pyrazine-benzothiophene / indole compound is any one of BN1-BN40: .
[0030] Secondly, the present invention also provides a method for preparing the above-mentioned pyrazine-benzothiophene / indole-containing compound, comprising the following steps: S1. Under a protective atmosphere, 3,5-difluoro-1,2-diamine undergoes a coupling reaction with a diketone compound containing R and X groups under weakly acidic conditions to yield a fluoro-benzothiophene / indole-containing quinoxaline, the structure of which is shown in Formula III. ; S2. Under a protective atmosphere, the fluoro-benzothiophene / indole-containing quinoxaline from step S1 undergoes a coupling reaction with iodine in a solution containing lithium diisopropylamino and tetrahydrofuran to obtain an iodine-fluoro-benzothiophene / indole-containing quinoxaline, the structure of which is shown in Formula IV: ; S3. Under a protective atmosphere, the iodine-fluorine-benzothiophene / indole-containing quinoxaline from step S2 is coupled with tert-butylcarbazole in N,N-dimethylformamide to obtain quinoxaline containing di-tert-butylcarbazole-iodine-fluorine-benzothiophene / indole, the structure of which is shown in Formula V. ; S4. Under a protective atmosphere, the quinoxaline containing di-tert-butylcarbazole-iodine-fluorine-benzothiophene / indole from step S3 is coupled with BBr3 in a solution containing n-butyllithium, N,N-diisopropylethylamine and trimethylbenzene to obtain a compound containing pyrazine-benzothiophene / indole.
[0031] The method for preparing compounds containing pyrazine-benzothiophene / indole provided by this invention first synthesizes quinoxaline containing pyrazine-benzothiophene / indole through a series of coupling reactions, and then performs a Buchwald-Hartwig coupling reaction between the quinoxaline containing pyrazine-benzothiophene / indole and BBr3 in a one-pot process to obtain compounds containing pyrazine-benzothiophene / indole. This method has the advantages of simple operation, mild reaction conditions and strong adaptability to reactants, and is suitable for large-scale production.
[0032] In one possible implementation, the molar ratio of 3,5-difluoro-1,2-diamine to the diketone compound containing R and X groups in step S1 is 3:2. Limiting the molar ratio of 3,5-difluoro-1,2-diamine to the diketone compound containing R and X groups to 3:2 is beneficial for improving the conversion rate of the product.
[0033] In one possible implementation, in step S2, the molar ratio of fluoro-benzothiophene / indole quinoxaline to iodine is 1:3, and the molar ratio of fluoro-benzothiophene / indole quinoxaline to lithium diisopropylaminodimethylamine is 1:2. Limiting the molar ratio of fluoro-benzothiophene / indole quinoxaline to iodine to 1:3 helps to shift the reaction to the right, suppresses side reactions, and improves product conversion. Limiting the molar ratio of fluoro-benzothiophene / indole quinoxaline to lithium diisopropylaminodimethylamine to 1:2 helps to suppress base consumption side reactions, ensures sufficient base for the target reaction, and avoids yield decrease due to insufficient base.
[0034] In one possible implementation, the molar ratio of iodine-fluorine-benzothiophene / indole-containing quinoxaline to tert-butylcarbazole in step S3 is 1:2.2. Limiting the molar ratio of iodine-fluorine-benzothiophene / indole-containing quinoxaline to tert-butylcarbazole to 1:2.2 can overcome the steric hindrance of tert-butylcarbazole and inhibit the occurrence of deboronization side reactions, thus improving the yield.
[0035] In one possible implementation, in step S4, the molar ratio of quinoxaline containing di-tert-butylcarbazole-iodine-fluorine-benzothiophene / indole to BBr3 is 1:2, the molar ratio of BBr3 to n-butyllithium is 4:3, and the molar ratio of BBr3 to N,N-diisopropylethylamine is 1:1. Limiting the molar ratio of quinoxaline containing di-tert-butylcarbazole-iodine-fluorine-benzothiophene / indole to BBr3 to 1:2, the molar ratio of BBr3 to n-butyllithium to 4:3, and the molar ratio of BBr3 to N,N-diisopropylethylamine to 1:1 not only suppresses side reactions but also allows the three-step formulation to produce a synergistic effect, avoiding intermediate separation losses and facilitating the efficient synthesis of compounds containing pyrazine-benzothiophene / indole.
[0036] Thirdly, the present invention also provides an organic electroluminescent device, wherein the light-emitting layer material of the organic electroluminescent device comprises the above-mentioned compound containing pyrazine-benzothiophene / indole.
[0037] In one possible implementation, the organic electroluminescent device comprises, from bottom to top, a transparent substrate, an ITO conductive glass anode, a hole injection layer HATCN, hole transport layers TAPC and TCTA, a light-emitting layer, an electron transport layer TmPyPb, an electron injection layer LiF, and a cathode layer Al. The light-emitting layer is composed of the aforementioned pyrazine-benzothiophene / indole compound as a dopant guest material, and DMIC-TRz and PO-01 as host materials. The mass percentage of the dopant guest material in the light-emitting layer is 1-3%, the mass percentage of DMIC-TRz is 85-90%, and the mass percentage of PO-01 is 8-12%. The structural formulas of HATCN, TAPC, TCTA, DMIC-TRz, PO-01, and TmPyPb are shown below: .
[0038] Based on common knowledge in the field, the above-described embodiments can be combined arbitrarily.
[0039] The reagents and raw materials used in this invention are all commercially available.
[0040] Example 1 This embodiment provides a compound BN-BTP containing pyrazine-benzothiophene, which is prepared by the following method: The preparation of D1, 8,10-difluoro[4,5]thieno[2,3-b]quinoxaline is shown in the following reaction formula: ; Nitrogen gas was introduced into a 500 mL three-necked round-bottom flask, followed by the addition of 3,5-difluoro-1,2-diamine (4.32 g, 30 mmol), benzo[b]thiophene-2,3-dione (3.28 g, 20 mmol), and 200 mL of acetic acid. The mixture was then stirred overnight at 120 °C. After the reaction was complete, the mixture was cooled, the organic solvent was removed, and the product was extracted with dichloromethane. The remaining solid was further separated and purified by silica gel column chromatography (using petroleum ether / dichloromethane as eluent) to obtain a pure, pale yellow powdery solid intermediate 1 (4.82 g, 17.7 mmol, yield 89%). The preparation of D2, 8,10-difluoro-9-iodo[4,5]thieno[2,3-b]quinoxaline, is shown in the following reaction formula: ; Nitrogen gas was introduced into a 250 mL three-necked round-bottom flask, and intermediate 1 (2.72 g, 10 mmol) from step D1 and 100 mL of tetrahydrofuran (THF) solvent were added. The mixture was then cooled to 0 °C and stirred for 20 min. Next, 10 mL (20 mmol) of lithium diisopropylamino (LDA) was slowly added, and the mixture was stirred at low temperature for 1 h. Then, elemental iodine (7.61 g, 30 mmol) was dissolved and slowly added, and the mixture was stirred at low temperature for another 20 min. The mixture was then stirred overnight at room temperature. After the reaction was complete, the solvent was removed, and the product was extracted with dichloromethane. The remaining solid was further purified by silica gel column chromatography (using petroleum ether / dichloromethane as eluent) to obtain a pure yellow powdery solid intermediate 2 (4.33 g, 10.9 mmol, yield 73%). The preparation of D3, 8,10-bis(3,6-di-tert-butylcarbazole)-9-iodo[4,5]thiophene[2,3-b]quinoxaline is shown in the following reaction formula: ; Nitrogen gas was introduced into a 250 mL three-necked round-bottom reaction flask. Intermediate 2 (3.98 g, 10 mmol), tert-butylcarbazole (6.15 g, 22 mmol), and 200 mL of N,N-dimethylformamide (DMF) from step D2 were added, and the mixture was stirred at 90 °C for 8 hours. After solvent removal, the reaction mixture was extracted with dichloromethane to separate the product. The obtained solid was further separated and purified by silica gel column chromatography (using petroleum ether / dichloromethane as eluent) to obtain pure orange solid intermediate 3 (5.82 g, 6.32 mmol, yield 63%). D4. Preparation of the compound BN-BTP containing pyrazine-benzothiophene, the reaction formula is as follows: ; In a 100 mL three-necked round-bottom reaction flask purged with nitrogen, intermediate 3 (2.75 g, 3 mmol) prepared in step D3 was added, followed by 20 mL of mesitylene, and the reaction system was cooled to -70 °C. Next, 600 μl (4.5 mmol) of n-butyllithium (n-BuLi) was added, and the mixture was stirred for 30 min. The reaction temperature was then raised to 50 °C and the reaction continued for 1 h. After the reaction was complete, the system was cooled to -40 °C, and BBr3 (300 μL, 6 mmol) was added. The mixture was stirred for another 30 min, and the system was then heated to room temperature and reacted for 1 h. Finally, the system was cooled to 0 °C, and 350 μl (6 mmol) of N,N-diisopropylethylamine (DIPEA) was added. The mixture was stirred for 30 min, and the temperature was then raised to 150 °C. The mixture was stirred overnight at ℃; after the reaction mixture was removed by solvent, it was extracted with dichloromethane to obtain the product; finally, the remaining solid was separated and purified by silica gel column chromatography (using petroleum ether / dichloromethane as eluent) to obtain a dark red solid product (980 mg, 1.23 mmol, yield 41%), which is the compound BN-BTP containing pyrazine-benzothiophene.
[0041] Example 2 This embodiment provides a compound BN-IDP containing pyrazine-indole, which is prepared by the following method: The preparation of D1, 8,10-difluoro[4,5]indolo[2,3-b]quinoxaline is shown in the following reaction formula: ; Nitrogen gas was introduced into a 250 mL three-necked round-bottom flask, followed by the addition of 3,5-difluoro-1,2-diamine (4.32 g, 30 mmol), benzo[b]furan-2,3-dione (2.94 g, 20 mmol), and 200 mL of acetic acid. The mixture was then stirred overnight at 120 °C. After the reaction was complete, the mixture was cooled, the organic solvent was removed, and the mixture was washed with dichloromethane and ethanol. The resulting product was extracted to obtain intermediate 4. The preparation of D2, 1,3-difluoro-2-indole-6-benzene[2,3-b]quinoxaline, is shown in the following reaction formula: ; Nitrogen gas was introduced into a 250 mL three-necked round-bottom reaction flask. Intermediate 4 (3.83 g, 15 mmol), iodobenzene (6.12 g, 30 mmol), 18-crown ether 6 (2.94 g, 20 mmol), copper / cuprous iodide (191 mg / 285 mg, 20% / 10%), potassium carbonate (6.22 g, 20 mmol), and 200 mL of o-dichlorobenzene solvent from step D1 were added. The mixture was stirred overnight at 220 °C. After the reaction was completed, the reaction mixture was cooled and the organic solvent was removed. The mixture was then washed with dichloromethane and ethanol, and extracted to obtain intermediate 5. The preparation of D3, 1,3-difluoro-2-indole-6-benzene-6H-iodo[2,3-b]quinoxaline, is shown in the following reaction formula: ; Nitrogen gas was introduced into a 250 mL three-necked round-bottom reaction flask. Intermediate 5 (3.31 g, 10 mmol) from step D2 and 100 mL of tetrahydrofuran solvent were added. The mixture was then cooled to 0 °C and stirred for 20 min. LDA (10 mL, 20 mmol) was then slowly added while stirring at low temperature for 1 h. Next, iodine (7.61 g, 30 mmol) was dissolved and slowly added, and stirring was continued at low temperature for 20 min. The mixture was then stirred at room temperature overnight. After the reaction was complete, the solvent was removed, and the mixture was washed with dichloromethane and ethanol. After extraction, intermediate 6 was obtained. The preparation of D4, 1,3-bis(3,6-di-tert-butylcarbazole)-2-iodo-6-phenyl-6H-indole[2,3-b]quinoxaline, is shown in the following reaction formula: ; After purging the 250 mL three-necked round-bottom reaction flask with nitrogen, intermediate 6 (2.74 g, 6 mmol), tert-butylcarbazole (3.69 g, 13.2 mmol), cesium carbonate (7.82 g, 24 mmol), and 200 mL of DMF from step D3 were added, and the mixture was stirred at 90 °C for 8 h. After solvent removal, the reaction mixture was extracted with dichloromethane to separate the product. The obtained solid was further separated and purified by silica gel column chromatography (using petroleum ether / dichloromethane as eluent) to obtain pure orange solid intermediate 7 (4.35 g, 4.46 mmol, yield 74%). D5. Preparation of BN-IPD, a compound containing pyrazine-indole, using the following reaction formula: ; In a 100 mL three-necked round-bottom reaction flask purged with nitrogen, intermediate 7 (3 g, 3 mmol) from step D4 was added, followed by 60 mL of mesitylene, and the reaction system was cooled to -70 °C. Next, 600 μl (4.5 mmol) of n-butyllithium (n-BuLi) was added, and the mixture was stirred for 30 min. The reaction temperature was then raised to 50 °C and the reaction continued for 1 h. After the reaction was complete, the system was cooled to -40 °C, and BBr3 (308 μL, 6 mmol) was added. The mixture was stirred for 30 min and then allowed to react at room temperature for 1 h. The system was then cooled to 0 °C, and 352 μL (6 mmol) of N,N-diisopropylethylamine (DIPEA) was added. The mixture was stirred for 30 min, and the temperature was then raised to 150 °C. The mixture was stirred overnight at ℃; after the reaction mixture was removed by solvent, it was extracted with dichloromethane to obtain the product; finally, the remaining solid was separated and purified by silica gel column chromatography (using petroleum ether / dichloromethane as eluent) to obtain a dark red solid product (966 mg, 1.12 mmol, yield 36%), which is the compound BN-IPD containing pyrazine-indole.
[0042] Example 3 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 6-phenyl-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 48%.
[0043] Example 4
[0044] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5-phenyl-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 53%.
[0045] Example 5
[0046] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4-phenyl-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 70%.
[0047] Example 6 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 6,7-diphenyl-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 65%.
[0048] Example 7
[0049] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5,6-diphenyl-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 68%.
[0050] Example 8 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5,7-diphenyl-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 57%.
[0051] Example 9 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4,5-diphenyl-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 55%.
[0052] Example 10 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4,7-diphenyl-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 62%.
[0053] Example 11 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 7-fluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 67%.
[0054] Example 12
[0055] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 6-fluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 51%.
[0056] Example 13
[0057] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5-fluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 69%.
[0058] Example 14
[0059] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4-fluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 58%.
[0060] Example 15
[0061] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 6,7-difluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 65%.
[0062] Example 16 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5,6-difluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 53%.
[0063] Example 17
[0064] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5,7-difluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 57%.
[0065] Example 18
[0066] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4,5-difluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 57%.
[0067] Example 19
[0068] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4,7-difluoro-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 59%.
[0069] Example 20
[0070] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 7-cyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 62%.
[0071] Example 21 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 6-cyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 69%.
[0072] Example 22
[0073] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5-cyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 65%.
[0074] Example 23
[0075] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4-cyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 71%.
[0076] Example 24
[0077] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 6,7-dicyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 61%.
[0078] Example 25
[0079] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5,6-dicyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 48%.
[0080] Example 26 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 5,7-dicyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 58%.
[0081] Example 27
[0082] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4,5-dicyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 55%.
[0083] Example 28
[0084] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of 4,7-dicyano-benzo[b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 62%.
[0085] Example 29
[0086] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of thieno[2,3-b]pyridine-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 63%.
[0087] Example 30
[0088] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of thieno[2,3-c]pyridine-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 73%.
[0089] Example 31 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of thieno[2,3-d]pyridine-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 66%.
[0090] Example 32
[0091] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of thieno[2,3-e]pyridine-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 53%.
[0092] Example 33
[0093] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of thieno[2,3-c]pyridine-5,6-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 55%.
[0094] Example 34
[0095] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of thieno[2,3-d]pyridine-5,6-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 60%.
[0096] Example 35
[0097] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of thieno[2,3-c]pyridine-6,7-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 71%.
[0098] Example 36 This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of thieno[2,3-b]pyridine-6,7-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 58%.
[0099] Example 37
[0100] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of naphtho[1,2-b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 53%.
[0101] Example 38
[0102] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of naphtho[2,3-b]thiophene-2,3-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 45%.
[0103] Example 39
[0104] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of naphtho[2,1-b]thiophene-1,2-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 65%.
[0105] Example 40
[0106] This embodiment provides a compound containing pyrazine-benzothiophene, the preparation method of which differs from that of Example 1 in that: In step D1, benzo[b]thiophene-2,3-dione was replaced with an equimolar amount of naphtho[2,3-b]thiophene-1,2-dione. All other raw materials and steps were the same as in Example 1. The final yield of the compound containing pyrazine-benzothiophene was 53%.
[0107] Example 41
[0108] This embodiment provides an organic electroluminescent device, comprising, from bottom to top, a glass substrate / indium tin oxide / HATCN (5 nm) / TAPC (30 nm) / TCTA (10 nm) / mCP (10 nm) / 1wt%BN-BTP or BN-IDP:10wt%PO-01:90wt%DMIC-TRz (30 nm) / TmPyPB (40 nm) / lithium fluoride (1 nm) / aluminum (150 nm). Indium tin oxide serves as the anode, HATCN as the hole injection layer, TAPC and TCTA as hole transport layers, the light-emitting layer is 1wt% BN-BTP or BN-IDP:10wt%PO-01:90wt%DMIC-TRz, TmPyPB as the electron transport layer, lithium fluoride as the electron injection layer, and aluminum as the cathode.
[0109] The structural formulas of TAPC, TCTA, TmPyPB, HAT-CN, DMIC-TRz, and PO-01 are as follows: ; The organic electroluminescent device provided in this embodiment is prepared by the following method: First, the transparent conductive indium tin oxide (ITO) glass substrate is ultrasonically cleaned for 15 minutes sequentially using a micron-level semiconductor-specific detergent, deionized water, acetone, and isopropanol to remove contaminants from the substrate surface. Then, the ITO glass substrate is placed in a constant temperature oven and dried at 80 degrees Celsius for later use. After drying, the ITO glass substrate is treated with oxygen plasma for 5 minutes to further remove surface-adhered organic contaminants. Finally, HATCN, TAPC, TCTA, BN-BTP, DMIC-TRz, PO-01, TmPyPB, lithium fluoride, and aluminum are deposited on the ITO glass substrate using vacuum thermal evaporation to obtain an organic electroluminescent device.
[0110] Example 42
[0111] This embodiment provides an organic electroluminescent device, which differs from Embodiment 41 in that the light-emitting layer is 1wt%BN-IDP:10wt%PO-01:90wt%DMIC-TRz, while all other aspects are the same as in Embodiment 41.
[0112] Test results description: Figure 1 The image shows the UV absorption and fluorescence emission spectra of BN-BTP prepared in Example 1. As can be seen from the figure, in the pyrazine-benzothiophene compound BN-BTP, pyrazine-benzothiophene acts as a strong electron donor, which can red-shift the spectrum, effectively achieving red light emission while maintaining a narrow spectral band.
[0113] Figure 2 The image shows the UV absorption and fluorescence emission spectra of the BN-IDP prepared in Example 2. As can be seen from the figure, in the pyrazine-benzothiophene-containing compound BN-IDP, pyrazine-indole acts as a strong electron donor, red-shifting the spectrum and effectively achieving red light emission while maintaining a narrow spectral band.
[0114] Figure 3 The graphs show the current density-voltage-luminescence relationship of the organic electroluminescent devices in Examples 41 and 42. As can be seen from the graphs, the organic electroluminescent devices provided in Examples 41 and 42 have a current density of approximately 300 mAcm² at 12.5 V. -2 Current density and more than 10 4 cd m -2 The brightness.
[0115] Figure 4 The figures show the emission spectra of the organic electroluminescent devices in Examples 41 and 42. As can be seen from the figures, the organic electroluminescent devices in Examples 41 and 42 can effectively achieve red light emission and maintain a narrow spectral band, with the organic electroluminescent device in Example 42 having an even narrower emission spectrum.
[0116] Figure 5 The graph shows the external quantum efficiency versus brightness relationship curves of the organic electroluminescent devices in Examples 41 and 42. As can be seen from the graph, the organic electroluminescent devices in Examples 41 and 42 both exhibit high external quantum efficiencies.
[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A pyrazine-benzothiophene / indole containing compound characterized in that, having a structure as shown in Formula I: ； wherein the X group is selected from at least one of S, O, N and Se, when the X group is N, a benzene ring is used to replace the nitrogen hydrogen bond to protect the N atom in the structure of Formula (II), ； R is selected from at least one of hydrogen, alkyl, fluorine, chlorine, bromine, iodine, nitrogen, cyano and an aromatic ring, the aromatic ring is selected from any one of a carbon and hydrogen composed aromatic ring, a carbon, nitrogen and hydrogen composed aromatic heterocycle, a carbon, oxygen and hydrogen composed aromatic heterocycle, a carbon, sulfur and hydrogen composed aromatic heterocycle, and a carbon, nitrogen, sulfur and hydrogen composed aromatic heterocycle.
2. The pyrazine-benzothiophene / indole containing compound according to claim 1, characterized in that, The synthesis raw material of the pyrazine-benzothiophene / indole containing compound includes a diketone compound containing an R group and an X group, the diketone compound has any one of RX1-RX40 structures: 。 3. The pyrazine-benzothiophene / indole containing compound according to claim 1, characterized in that, The pyrazine-benzothiophene / indole containing compound is any one of BN1-BN40: 。 4. A process for the preparation of a compound according to any one of claims 1 to 3, characterized in that, comprising the following steps: S1. In a protective atmosphere, 3,5-difluoro-1,2-diamine is coupled with a diketone compound containing an R group and an X group under weak acid conditions to obtain a fluorine-benzothiophene / indole containing quinoxaline, which has a structure as shown in Formula III: ； S2. In a protective atmosphere, the fluorine-benzothiophene / indole containing quinoxaline in step S1 is coupled with iodine in a solution containing lithium diisopropylamine and tetrahydrofuran to obtain an iodine-fluorine-benzothiophene / indole containing quinoxaline, which has a structure as shown in Formula IV: ； S3. In a protective atmosphere, the iodine-fluorine-benzothiophene / indole containing quinoxaline in step S2 is coupled with tert-butyl carbazole in N,N-dimethylformamide to obtain a di-tert-butyl carbazole-iodine-fluorine-benzothiophene / indole containing quinoxaline, which has a structure as shown in Formula V: ； S4. In a protective atmosphere, the di-tert-butyl carbazole-iodine-fluorine-benzothiophene / indole containing quinoxaline in step S3 is coupled with BBr3 in a solution containing n-butyllithium, N,N-diisopropylethylamine and trimethylbenzene to obtain a pyrazine-benzothiophene / indole containing compound.
5. The preparation method of the pyrazine-benzothiophene / indole containing compound according to claim 4, wherein: the molar ratio of the 3,5-difluoro-1,2-diamine to the diketone compound containing an R group and an X group in step S1 is 3:
2.
6. The process for the preparation of pyrazine-benzothiophene / indole containing compounds according to claim 4, characterized in that, the molar ratio of the fluorine-benzothiophene / indole containing quinoxaline to the iodine in step S2 is 1:3, and the molar ratio of the fluorine-benzothiophene / indole containing quinoxaline to the lithium diisopropylamine is 1:
2.
7. The process for the preparation of pyrazine-benzothiophene / indole containing compounds according to claim 4, characterized in that, the molar ratio of the iodine-fluorine-benzothiophene / indole containing quinoxaline to the tert-butyl carbazole in step S3 is 1:2.
2.
8. The process for the preparation of pyrazine-benzothiophene / indole containing compounds as claimed in claim 4, wherein, the molar ratio of the di-tert-butyl carbazole-iodine-fluorine-benzothiophene / indole containing quinoxaline to the BBr3 in step S4 is 1:2, the molar ratio of the BBr3 to the n-butyllithium is 4:3, and the molar ratio of the BBr3 to the N,N-diisopropylethylamine is 1:
1.
9. An organic electroluminescent device, characterized by The light-emitting layer material composition of the organic electroluminescent device includes the pyrazine-benzothiophene / indole containing compound according to any one of claims 1-3.
10. The organic electroluminescent device according to claim 9, characterized in that, The organic electroluminescence device is sequentially arranged from bottom to top as a transparent substrate, an ITO conductive glass anode, a hole injection layer HATCN, a hole transport layer TAPC and TCTA, a light-emitting layer, an electron transport layer TmPyPb, an electron injection layer LiF and a cathode layer Al; the light-emitting layer is composed of the pyrazine-benzothiophene / indole-containing compound as a doping guest material and DMIC-TRz and PO-01 as host materials, the mass percentage of the doping guest material in the light-emitting layer is 1-3%, the mass percentage of the DMIC-TRz is 85-90%, and the mass percentage of the PO-01 is 8-12%, and the structural formulae of the HATCN, the TAPC, the TCTA, the DMIC-TRz, the PO-01 and the TmPyPb are as follows: 。