Condensed heterocyclic compound and organic electroluminescent element containing same

Abstract

The invention discloses a fused heterocyclic compound and an organic electroluminescent element containing the same, groups with strong electron withdrawing effect, including pyrazine, benzothiophene, cyano-substituted pyrazine and cyano-substituted benzothiophene, are introduced into a boron-nitrogen structural unit, and meanwhile, molecules are locked to keep a planar structure, so that the structure of the fused heterocyclic compound is enhanced. The red shift of the fluorescence emission spectrum is promoted to obtain the narrow-spectrum orange-red light-emitting material.

Description

Technical Field

[0001] The present invention relates to a luminescent material and application thereof, in particular to a novel condensed heterocyclic compound and an organic electroluminescent element containing the compound. Background Art

[0002] Compared with liquid crystal displays (LCDs), organic light emitting diodes (OLEDs) have the advantages of being thin, bright, and beautiful, not requiring a background light source, having a wide color gamut, a wide viewing angle, and having an excellent response speed. They can also be used to produce flexible, large-sized ultra-thin panels. As a rapidly developing, highly integrated new display technology, organic light emitting diodes have been widely used in display products of various sizes, such as smartphones, computers, car displays, and televisions. It is expected that with the development and optimization of materials and devices and the reduction of costs, OLEDs will be further used in creative display products such as large-size displays and flexible screens. OLED is a DC-driven PN junction structure light-emitting element with a single or multiple layers of organic functional films sandwiched between the anode and the cathode. The specific working process is as follows: under the action of the electric field, the hole carriers generated by the anode and the electron carriers generated by the cathode are injected into the hole injection layer and the electron injection layer respectively, and further migrate to the light-emitting layer after passing through the hole transport layer and the electron transport layer. The electrons and holes in the light-emitting layer meet to generate hole-electron pairs and further recombine to generate excitons, making the light-emitting molecules reach the excited state. When the light-emitting molecules release energy from the excited state and return to the ground state, visible light of the corresponding energy level is generated.

[0003] In OLED, the material that plays a decisive role in key indicators such as luminescence spectrum, luminescence efficiency and device life is the luminescent layer material, especially the guest material doped in the luminescent layer. In recent years, multi-resonance thermally activated delayed fluorescence (MR-TADF) materials have attracted widespread attention from the scientific research and industry circles due to their advantages of high color purity and high luminescence efficiency (Adv. Mater. 2016, 28, 2777–2781). However, the light color of MR-TADF materials has been limited to the blue-green light region, and high-efficiency, narrow-emission red light emitting materials are in short supply, thus limiting their further application in the display field. Summary of the invention

[0004] In view of the above problems, one of the objects of the present invention is to provide a novel fused heterocyclic compound, namely: 1) a novel fused heterocyclic compound, characterized in that the compound is represented by the general formula 1-4:

[0005]

[0006] Among them, X1 Indicates no bond or single bond;

[0007] R b1 ~R b4 are each independently a hydrogen atom or a cyano group;

[0008] R a1 ~R a14 are each independently a hydrogen atom or a substituent;

[0009] R as a substituent a1 ~R a14 each independently represents: a deuterium atom, a halogen atom, a cyano group, a nitro group, a substituted silicon group, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkene group having 1 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted monovalent heterocyclic group having 5 to 50 ring atoms;

[0010] R a7 With R a8 and R a10 With R a11 They may be bonded to each other as a group to form a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted monovalent heterocyclic group having 5 to 50 ring atoms.

[0011] 2) The fused heterocyclic compound according to 1) above, characterized in that R a1 ~R a14 and R b1 ~R b4The substituent groups are independently: hydrogen atom, deuterium atom, chlorine atom, bromine atom, fluorine atom, cyano group, nitro group, substituted silicon group, substituted or unsubstituted methyl group, substituted or unsubstituted ethyl group, substituted or unsubstituted n-propyl group, substituted or unsubstituted isopropyl group, substituted or unsubstituted n-butyl group, substituted or unsubstituted isobutyl group, substituted or unsubstituted sec-butyl group, substituted or unsubstituted tert-butyl group, substituted or unsubstituted 2-methylbutyl group, substituted or unsubstituted n-pentyl group, substituted or unsubstituted sec-pentyl group, substituted or unsubstituted trifluoromethyl group, substituted substituted or unsubstituted pentafluoroethyl, substituted or unsubstituted 2,2,2-trifluoroethyl, substituted or unsubstituted vinyl, substituted or unsubstituted propenyl, substituted or unsubstituted n-butenyl, substituted or unsubstituted isobutenyl, substituted or unsubstituted n-pentenyl, substituted or unsubstituted isopentenyl, substituted or unsubstituted neopentenyl, substituted or unsubstituted ethynyl, substituted or unsubstituted propynyl, substituted or unsubstituted n-butynyl, substituted or unsubstituted isobutynyl, substituted or unsubstituted n-pentynyl, substituted or unsubstituted isopentenyl substituted or unsubstituted neopentynyl, substituted or unsubstituted cyclopropyl, substituted or unsubstituted cyclobutyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted adamantyl, substituted or unsubstituted thienyl, substituted or unsubstituted indolyl, substituted or unsubstituted furanyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted indenyl, substituted or unsubstituted substituted fluorenyl, substituted or unsubstituted spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted naphthacene, substituted or unsubstituted benzothiazolyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzothiazolyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzoselenophene, substituted or unsubstituted carbazolyl.

[0012] The R a7 With R a8 and R a10 With R a11The rings are independently: substituted or unsubstituted cyclopropyl, substituted or unsubstituted cyclobutyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted adamantyl, substituted or unsubstituted thienyl, substituted or unsubstituted indolyl, substituted or unsubstituted furanyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted indenyl, substituted or unsubstituted substituted or unsubstituted fluorenyl, substituted or unsubstituted spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted naphthacene, substituted or unsubstituted benzothiazolyl, substituted or unsubstituted benzothiophene, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzothiazolyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzoselenophene, substituted or unsubstituted carbazolyl.

[0013] 3. The fused heterocyclic compound according to 1) or 2) above, wherein the "substituted" in the "substituted or unsubstituted" in the fused heterocyclic compound means that the substituent is independently a deuterium atom, a tritium atom, a halogen atom, a cyano group, a nitro group, a hydroxyl group, a monovalent alkyl group or a cycloalkyl group having 1 to 10 carbon atoms, a monovalent monocyclic aromatic group or a condensed aromatic group having 6 to 30 carbon atoms, or a monovalent heterocyclic group or a condensed heteroaryl group having 2 to 50 carbon atoms.

[0014] 4. The fused heterocyclic compound according to any one of 1) to 3) above, wherein the fused heterocyclic compound is selected from the following structures:

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] 5) An organic electroluminescent element, wherein the organic electroluminescent element comprises an anode, a cathode and at least one organic thin film located between the anode and the cathode, and the organic thin film contains the compound described in any one of 1) to 4) above.

[0026] 6) An organic electroluminescent element according to 5) above, wherein the organic thin film includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an exciton blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer, or a combination of at least two of them, and the light-emitting layer contains the compound described in any one of 1) to 4) above.

[0027] 7) The organic electroluminescent device according to 6) above, characterized in that the compound is used as a light-emitting material in the organic electroluminescent device, preferably a guest light-emitting material.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] Since the energy gap difference of the BN molecule itself is large, the method for realizing red light is usually to introduce multiple BN units on a large plane to expand conjugation (Adv.Mater.2023,35,2301018), so that the energy gap difference of the entire molecule is reduced, and the luminescence can be red-shifted to the red light region. But the problem brought about by this is that the molecular weight will be relatively large and not easy to sublimate; the molecular conjugation plane is large, and it is easy to self-aggregate, resulting in reduced efficiency. In order to solve these problems, the molecule of the present invention has only one BN unit to introduce a group with strong electron-withdrawing effect, including pyrazine, benzopyrazine, cyano-substituted pyrazine, and cyano-substituted benzopyrazine, which effectively reduces the LUMO energy level of the molecule, reduces the molecular energy gap difference, and realizes orange-red light or red light emission. The compound of the present invention has a small molecular weight, has greater flexibility in molecular design, can introduce more steric groups around the molecule, effectively protects the luminescent core, avoids self-aggregation, and improves luminous efficiency. The OLED prepared using the compound of the present invention has excellent performance, high external quantum efficiency, low efficiency roll-off characteristics, and stable narrow-spectrum orange-red or red light electroluminescence performance, and has good application prospects in the display field. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structure of an organic electroluminescent element prepared in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] Example

[0032] The features of the present invention are further specifically described below with reference to a number of synthesis examples. The scope of the present invention is not limited to the specific examples shown below.

[0033] Synthesis Example 1: Synthesis of H3

[0034]

[0035] Synthesis of intermediate 1a: Weigh 2.2g (10mmol) N-quinoxaline aniline, 1.48g (10mmol) 1,3-difluoro-2-chlorobenzene, 4.6g (14mmol) cesium carbonate in a flask, add 80ml dry N,N-dimethylformamide, purify the air, react at 120℃ for 10h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 100ml water, precipitate yellow solid, filter. Collect the solid, separate on a silica gel column to obtain 2.8g product, with a yield of 80%, and the molecular weight measured by mass spectrometry is m / z=349.79 (M+H) + .

[0036] Synthesis of intermediate 1b: Weigh 2.24g (8mmol) 3,6-di-tert-butylcarbazole, 2.8g (8mmol) intermediate 1a, 3.2g (10mmol) cesium carbonate in a flask, add 50ml dry N,N-dimethylformamide, purify, react at 100℃ for 10h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 100ml water, precipitate yellow solid, filter. Collect the solid, separate on a silica gel column to obtain 3.2g product, with a yield of 80%, and the molecular weight measured by mass spectrometry is m / z=499.01 (M+H) + .

[0037] Synthesis of intermediate 1c: Weigh 3.0g (6mmol) of intermediate 1b and dissolve it in 50ml of tetrahydrofuran, add 1.12g (6.2mmol) of NBS, and stir at room temperature for 2h in the dark. Stop the reaction, extract with water / ethyl acetate, remove the solvent by rotary evaporation, and separate with silica gel column to obtain intermediate 1c, yellow solid, 4.5g, yield 80%, and molecular weight measured by mass spectrometry is m / z=656.81 (M+H) + .

[0038] Synthesis of intermediate 1d: Weigh: 4.1g (5mmol) of intermediate 1c was dissolved in dry tetrahydrofuran and stirred at -78℃ for 10 minutes. Under nitrogen protection, 4.2ml of n-butyl lithium in n-hexane solution (10.5mmol, 2.5M) was added to the reaction solution. After the addition was complete, it was stirred at low temperature for 1h. Weigh 0.77mL (10.5mmol) of acetone and add it to the reaction solution, return to room temperature naturally, and react for 2h. Add 20ml of water to quench the reaction, extract with ethyl acetate / water three times, collect the organic phase, remove the solvent by rotary evaporation, and separate with silica gel column to obtain the crude product. The crude product was dissolved in 30ml of dichloromethane, stirred at room temperature, and 2.0g (14mmol) of boron trifluoride ether was added dropwise under nitrogen protection. Stir at room temperature for 1h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 2.0 g of intermediate 1d as a yellow solid with a yield of 70%. The molecular weight measured by mass spectrometry was m / z=579.14 (M+H) + .

[0039] Synthesis of H3: Weigh 1.74g (3mmol) of intermediate 1d and dissolve it in 20ml of dry tert-butylbenzene. Protect with nitrogen. Add 1.24ml of tert-butyl lithium solution (3.1mmol, 2.5M) dropwise at -78℃, stir at low temperature for 1h, add 0.9g (3.6mmol) of boron tribromide, stir at low temperature for 1h, and stir at room temperature for 1h. Add 0.47g (3.6mmol) of diisopropylethylamine, heat to 120℃ and react for 10h. Stop the reaction, cool to room temperature, add sodium carbonate solution to neutralize to neutrality, extract three times with dichloromethane, collect the organic phase, spin dry the solvent, separate on a silica gel column, and obtain 0.9g of the target product. Orange-red solid, yield 60%, molecular weight measured by mass spectrometry is m / z=552.49 (M+H) + .

[0040] Synthesis Example 2: Synthesis of H32

[0041]

[0042] Synthesis of intermediate 2a: Weigh 5.5g (21mmol) N-(6,7-dicyanoquinoxaline)-2-aniline, 2.24g (10mmol) 1,3-difluoro-2-chloro-5-phenyl-benzene, 16g (50mmol) cesium carbonate in a flask, add 200ml dry N,N-dimethylformamide, purify the air, react at 150℃ for 20h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 500ml water, precipitate brown solid, filter. Collect the solid, separate on a silica gel column to obtain 6.5g product, with a yield of 90%, and the molecular weight measured by mass spectrometry is m / z=727.19 (M+H) + .

[0043] Synthesis of intermediate 2b: Weigh 3.6g (5mmol) of intermediate 2a and dissolve it in 100ml of tetrahydrofuran, add 3.0g (15mmol) of NBS, and stir at room temperature in the dark for 10h. Stop the reaction, extract with water / ethyl acetate, remove the solvent by rotary evaporation, and separate with silica gel column to obtain intermediate 2b, a brown solid, 3.7g, with a yield of 85%. The molecular weight measured by mass spectrometry is m / z=884.98 (M+H) + .

[0044] Synthesis of intermediate 2c: Weigh: 4.4g (5mmol) of intermediate 2b was dissolved in dry tetrahydrofuran and stirred at -78°C for 10 minutes. Under nitrogen protection, 4ml of n-butyl lithium in n-hexane solution (10.2mmol, 2.5M) was added to the reaction solution. After the addition was complete, it was stirred at low temperature for 1h. Weigh 0.4mL (5.1mmol) of acetone and add it to the reaction solution, return to room temperature naturally, and react for 2h. Add 100ml of water to quench the reaction, extract with ethyl acetate / brine three times, collect the organic phase, remove the solvent by rotary evaporation, and separate with silica gel column to obtain the crude product. The crude product was dissolved in 30ml of dichloromethane, stirred at room temperature, and 0.73g (5.1mmol) of boron trifluoride ether was added dropwise under nitrogen protection. Stir at room temperature for 1h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 3.2 g of intermediate 2c as a brown solid with a yield of 80%. The molecular weight measured by mass spectrometry was m / z=807.32 (M+H) + .

[0045] Synthesis of H32: Weigh 3.2g (4mmol) of intermediate 2c and dissolve it in 100ml of dry tert-butylbenzene, protect with nitrogen, add 3.2ml of tert-butyl lithium solution (8mmol, 2.5M) dropwise at -78℃, stir at low temperature for 1h, add 2g (8mmol) of boron tribromide, stir at low temperature for 2h, and stir at room temperature for 2h. Add 1g (8mmol) of diisopropylethylamine, heat to 120℃ and react for 10h. Stop the reaction, cool to room temperature, add sodium carbonate solution to neutralize to neutrality, extract three times with dichloromethane, collect the organic phase, spin dry the solvent, separate with silica gel column, and obtain 2.3g of target product. Brown solid, yield 75%, molecular weight measured by mass spectrometry is m / z=780.66 (M+H) + .

[0046] Synthesis Example 3: Synthesis of H76

[0047]

[0048] Synthesis of intermediate 3a: Weigh 5.8g (21mmol) N-(4-tert-butylphenyl)quinoxaline-2-amine, 1.48g (10mmol) 1,3-difluoro-2-chlorobenzene, 12g (40mmol) cesium carbonate in a flask, add 120ml dry N,N-dimethylformamide, purify the air, react at 90°C for 15h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 200ml water, precipitate a yellow solid, and filter. Collect the solid, separate on a silica gel column to obtain 5.4g of the product, with a yield of 82%. The molecular weight measured by mass spectrometry is m / z = 663.27 (M+H) + .

[0049] Synthesis of intermediate 3b: Weigh 3.3g (5mmol) of intermediate 3a and dissolve it in 80ml of tetrahydrofuran, add 2.1g (12mmol) of NBS, and stir at room temperature for 2h in the dark. Stop the reaction, extract with water / ethyl acetate, remove the solvent by rotary evaporation, and separate with silica gel column to obtain intermediate 3b, yellow solid, 3.2g, yield 78%, and molecular weight measured by mass spectrometry is m / z=821.06 (M+H) + .

[0050] Synthesis of intermediate 3c: Weigh: 3.3g (4mmol) of intermediate 3b was dissolved in dry tetrahydrofuran and stirred at -78°C for 30 minutes. Under nitrogen protection, 10ml of n-butyl lithium in n-hexane solution (25mmol, 2.5M) was added to the reaction solution. After the addition was complete, it was stirred at low temperature for 30 minutes. Weigh 2.2mL (30mmol) of acetone and add it to the reaction solution, return to room temperature naturally, and react for 1h. Add 5ml of water to quench the reaction, extract with ethyl acetate / brine three times, collect the organic phase, remove the solvent by rotary evaporation, and separate with silica gel column to obtain the crude product. The crude product was dissolved in 20ml of dichloromethane, stirred at room temperature, and 4.0g (28mmol) of boron trifluoride ether was added dropwise under nitrogen protection. Stir at room temperature for 2h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 2 g of intermediate 3c as an orange solid with a yield of 55%. The molecular weight measured by mass spectrometry was m / z=743.4 (M+H) + .

[0051] Synthesis of H76: Weigh 2.2g (3mmol) of intermediate 3c and dissolve it in 50ml of dry tert-butylbenzene. Protect with nitrogen. Add 1.6ml of tert-butyl lithium solution (4mmol, 2.5M) dropwise at -78℃, stir at low temperature for 2h, add 2g (8mmol) of boron tribromide, stir at low temperature for 2h, and stir at room temperature for 2h. Add 1g (8mmol) of diisopropylethylamine, heat to 100℃ and react for 10h. Stop the reaction, cool to room temperature, add sodium carbonate solution to neutralize to neutrality, extract with dichloromethane three times, collect the organic phase, spin dry the solvent, separate with silica gel column, and obtain 1.5g of the target product as an orange-red solid with a yield of 70%. The molecular weight measured by mass spectrometry is m / z=716.74 (M+H). + .

[0052] Synthesis Example 4: Synthesis of H127

[0053]

[0054] Synthesis of intermediate 4a: Weigh 3.3g (10mmol) 6,7-dicyanoquinoxaline-2-(4-tert-butylphenyl)-amine, 1.48g (10mmol) 1,3-difluoro-2-chlorobenzene, 4.8g (15mmol) cesium carbonate in a flask, add 180ml dry N,N-dimethylformamide, purify the air, react at 90°C for 20h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 200ml water, precipitate orange solid, filter. Collect the solid, separate on a silica gel column to obtain 4.1g product, with a yield of 90%, and the molecular weight measured by mass spectrometry is m / z = 455.92 (M+H) + .

[0055] Synthesis of intermediate 4b: Weigh 3.6g (10mmol) N-(4-tert-butylphenyl)phenyl-4-tert-butylaniline, 4.5g (10mmol) intermediate 4a, 6.4g (20mmol) cesium carbonate in a flask, add 150ml dry N, N-dimethylformamide, purify the air, react at 140°C for 8h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 150ml water, precipitate a yellow-brown solid, and filter. Collect the solid, separate on a silica gel column to obtain 7g of product, with a yield of 90%, and the molecular weight measured by mass spectrometry is m / z=793.46 (M+H) + .

[0056] Synthesis of intermediate 4c: Weigh 3.9g (5mmol) of intermediate 1b and dissolve it in 50ml of tetrahydrofuran, add 1.8g (10mmol) of NBS, and stir at room temperature for 2h in the dark. Stop the reaction, extract with water / ethyl acetate, remove the solvent by rotary evaporation, and separate with silica gel column to obtain intermediate 4c, a yellow-brown solid, 3.5g, with a yield of 80%, and a molecular weight of m / z = 951.25 (M+H) by mass spectrometry. +.

[0057] Synthesis of intermediate 4d: Weigh: 4.5g (5mmol) of intermediate 4c was dissolved in dry tetrahydrofuran and stirred at -78°C for 60 minutes. Under nitrogen protection, 4ml of n-butyl lithium in n-hexane solution (10mmol, 2.5M) was added to the reaction solution. After the addition was complete, it was stirred at low temperature for 1h. Weigh 0.72mL (10mmol) of acetone and add it to the reaction solution, return to room temperature naturally, and react for 2h. Add 200ml of water to quench the reaction, extract with ethyl acetate / water three times, collect the organic phase, remove the solvent by rotary evaporation, and separate with silica gel column to obtain the crude product. The crude product was dissolved in 50ml of dichloromethane, stirred at room temperature, and 2.1g (15mmol) of boron trifluoride ether was added dropwise under nitrogen protection. Stir at room temperature for 1h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 2.6 g of intermediate 4d as a brown solid with a yield of 60%. The molecular weight measured by mass spectrometry was m / z=873.59 (M+H) + .

[0058] Synthesis of H127: Weigh 2.6g (3mmol) of intermediate 4d and dissolve it in 50ml of dry tert-butylbenzene. Protect with nitrogen. Add 1.24ml of tert-butyl lithium solution (3.1mmol, 2.5M) dropwise at -78℃, stir at low temperature for 1h, add 0.8g (3.1mmol) of boron tribromide, stir at low temperature for 1h, and stir at room temperature for 1h. Add 0.4g (3.1mmol) of diisopropylethylamine, heat to 100℃ and react for 20h. Stop the reaction, cool to room temperature, add sodium carbonate solution to neutralize to neutrality, extract three times with dichloromethane, collect the organic phase, spin dry the solvent, separate on a silica gel column, and obtain 1.5g of the target product. Brown solid, yield 60%, molecular weight measured by mass spectrometry is m / z=846.93 (M+H) + .

[0059] Synthesis Example 5: Synthesis of H166

[0060]

[0061] Synthesis of intermediate 5a: Weigh 4.7g (21mmol) N-(4-(tert-butyl)phenyl)pyrazine-2-amine, 1.48g (10mmol) 1,3-difluoro-2-chlorobenzene, 4.9g (15mmol) cesium carbonate in a flask, add 60ml dry N,N-dimethylformamide, purify, react at 100℃ for 6h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 200ml water, precipitate yellow solid, filter. Collect the solid, separate on a silica gel column to obtain 4.8g product, with a yield of 85%, and the molecular weight measured by mass spectrometry is m / z=563.15 (M+H) + .

[0062] Synthesis of intermediate 5b: Weigh 2.8g (5mmol) of intermediate 5a and dissolve it in 50ml of tetrahydrofuran, add 3.0g (15mmol) of NBS, and stir for 2h at 50° in the dark. Stop the reaction, extract with water / ethyl acetate, remove the solvent by rotary evaporation, and separate with silica gel column to obtain intermediate 5b, yellow solid, 3g, yield 82%, and molecular weight measured by mass spectrometry is m / z=720.94 (M+H) + .

[0063] Synthesis of intermediate 5c: Weigh: 3.6g (5mmol) of intermediate 5b was dissolved in dry tetrahydrofuran and stirred at -78°C for 50 minutes. Under nitrogen protection, 2ml of n-butyl lithium in n-hexane solution (5.1mmol, 2.5M) was added to the reaction solution. After the addition was complete, it was stirred at low temperature for 2h. Weigh 0.91g (5.1mmol) of 9-fluorenone and add it to the reaction solution, return to room temperature naturally, and react for 1h. Add 50ml of water to quench the reaction, extract with ethyl acetate / brine three times, collect the organic phase, remove the solvent by rotary evaporation, separate with silica gel column, and obtain the crude product. Dissolve the crude product in 100ml of dichloromethane, stir at room temperature, and under nitrogen protection, add 1.4g (10mmol) of boron trifluoride ether. Stir at room temperature for 1h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 3.4 g of intermediate 5c as an orange solid with a yield of 76%. The molecular weight measured by mass spectrometry was m / z=887.53 (M+H) + .

[0064] Synthesis of H166: Weigh 5.3g (6mmol) of intermediate 5c and dissolve it in 100ml of dry tert-butylbenzene. Protect with nitrogen. Add 4ml of tert-butyl lithium solution (10mmol, 2.5M) dropwise at -78℃, stir at low temperature for 1h, add 4g (16mmol) of boron tribromide, stir at low temperature for 1h, and stir at room temperature for 1h. Add 2g (16mmol) of diisopropylethylamine, heat to 130℃ and react for 12h. Stop the reaction, cool to room temperature, add sodium carbonate solution to neutralize to neutrality, extract three times with dichloromethane, collect the organic phase, spin dry the solvent, separate on a silica gel column, and obtain 3.6g of the target product. Orange-red solid, yield 70%, molecular weight measured by mass spectrometry is m / z=860.87 (M+H) + .

[0065] Synthesis Example 6: Synthesis of H239

[0066]

[0067] Synthesis of intermediate 6a: Weigh 3.3g (10mmol) 6,7-dicyanoquinoxaline-2-(4-tert-butylphenyl)-amine, 1.48g (10mmol) 1,3-difluoro-2-chlorobenzene, 4.8g (15mmol) cesium carbonate in a flask, add 180ml dry N,N-dimethylformamide, purify the air, react at 90°C for 20h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 200ml water, precipitate orange solid, filter. Collect the solid, separate on a silica gel column to obtain 4.1g product, with a yield of 90%, and the molecular weight measured by mass spectrometry is m / z = 455.92 (M+H) + .

[0068] Synthesis of intermediate 6b: Weigh 3.55g (10mmol) 3-(4-tert-butylphenyl)-6-tert-butylcarbazole, 4.5g (10mmol) intermediate 4a, 6.4g (20mmol) cesium carbonate in a flask, add 150ml dry N, N-dimethylformamide, purify, react at 140℃ for 8h under nitrogen protection. Stop the reaction, cool to room temperature, pour into 150ml water, precipitate brown solid, filter. Collect the solid, separate on a silica gel column to obtain 6.3g product, with a yield of 80%, and the molecular weight measured by mass spectrometry is m / z=791.44 (M+H) + .

[0069] Synthesis of intermediate 6c: Weigh 3.9g (5mmol) of intermediate 6b and dissolve it in 50ml of tetrahydrofuran, add 1.8g (10mmol) of NBS, and stir at room temperature for 1h in the dark. Stop the reaction, extract with water / ethyl acetate, remove the solvent by rotary evaporation, and separate with silica gel column to obtain intermediate 6c, a brown solid, 2.8g, with a yield of 60%, and a molecular weight of m / z = 949.23 (M+H) by mass spectrometry. + .

[0070] Synthesis of intermediate 6d: Weigh: 4.75g (5mmol) of intermediate 6c was dissolved in dry tetrahydrofuran and stirred at -78°C for 10 minutes. Under nitrogen protection, 6ml of n-butyl lithium in n-hexane solution (15mmol, 2.5M) was added to the reaction solution. After the addition was complete, it was stirred at low temperature for 1h. Weigh 1.4mL (20mmol) of acetone and add it to the reaction solution, return to room temperature naturally, and react for 2h. Add 50ml of water to quench the reaction, extract with ethyl acetate / water three times, collect the organic phase, remove the solvent by rotary evaporation, and separate with silica gel column to obtain the crude product. The crude product was dissolved in 50ml of dichloromethane, stirred at room temperature, and 2.1g (15mmol) of boron trifluoride ether was added dropwise under nitrogen protection. Stir at room temperature for 1h, stop the reaction, add sodium carbonate solution to neutralize the reaction solution, and extract with dichloromethane three times. The solvent was removed by rotary evaporation and separated by silica gel column to obtain 3.5 g of intermediate 6d as a brown solid with a yield of 80%. The molecular weight measured by mass spectrometry was m / z=871.57 (M+H)+ .

[0071] Synthesis of H239: Weigh 4.3g (5mmol) of intermediate 4d and dissolve it in 50ml of dry tert-butylbenzene. Protect with nitrogen. Add 2.4ml of tert-butyl lithium solution (6mmol, 2.5M) dropwise at -78℃, stir at low temperature for 1h, add 1.6g (6mmol) of boron tribromide, stir at low temperature for 1h, and stir at room temperature for 1h. Add 0.8g (6mmol) of diisopropylethylamine, heat to 150℃ and react for 8h. Stop the reaction, cool to room temperature, add sodium carbonate solution to neutralize to neutrality, extract three times with dichloromethane, collect the organic phase, spin dry the solvent, separate on a silica gel column, and obtain 2.5g of the target product. Brown solid, yield 60%, molecular weight measured by mass spectrometry is m / z=844.91 (M+H) + .

[0072] Device Example:

[0073] A 30 mm × 30 mm × 1.1 mm thick glass substrate with an indium tin oxide (ITO) transparent electrode (anode) was ultrasonically cleaned in isopropyl alcohol for 5 minutes, and then cleaned with ultraviolet ozone for 30 minutes. The cleaned glass substrate was mounted on the substrate rack of a vacuum evaporation device and evacuated to 1×10 -5 ~1×10 -6 Pa, HATCN hole injection layer (HIL) is evaporated on the ITO transparent electrode with a film thickness of 15nm. HT is evaporated on the hole injection layer as a hole transport layer (HTL) with a film thickness of 60nm. Then, EB is evaporated on the hole transport layer as an electron blocking layer (EBL) with a film thickness of 40nm. Then, a light-emitting layer (EML) is co-evaporated on the electron blocking layer with a film thickness of 40nm; the light-emitting layer (EML) adopts a multi-source co-evaporation method to evaporate the main material (HOST) and the light-emitting material of the light-emitting layer, wherein the doping concentration of the light-emitting material is 2%wt. Then HB is evaporated on the light-emitting layer as a hole blocking layer (HBL) with a film thickness of 5nm. Then on the hole blocking layer, an electron transport material (ET) and 8-hydroxyquinoline lithium (Liq) are co-evaporated 1:1 as an electron transport layer (ETL) with a film thickness of 30nm. In addition, Liq is evaporated on the ETL as an electron injection layer (EIL) with a film thickness of 1nm. Then, a metal cathode aluminum (Al) is evaporated on the EIL to a thickness of 100 nm. The structure of the organic electroluminescent device of device example 1 is as follows: Figure 1 As shown, Figure 1 The stacking order and role of each functional layer are also shown.

[0074] The OLED has in principle the following layer structure: ITO substrate / hole injection layer (HIL) / hole transport layer (HTL) / electron blocking layer (EBL) / luminescent layer (EML) / hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL) and finally cathode. The cathode is formed by an aluminum layer with a thickness of 100 nm. The exact structure of the OLED is shown in Table 1.

[0075] Table 1 Materials used for OLED

[0076]

[0077] Device Example 1:

[0078] ITO(130) / HATCN(15) / HT(60) / EB(10) / HOST:H3(20,2%wt) / HB(5) / ET:Liq(30,50%wt) / Liq(1) / Al(100)

[0079] The only difference between device examples 2-30 and device example 1 is that the H3 of the present invention used in the light-emitting layer is replaced by other compounds of the present invention. The performance test data of the obtained devices are shown in Table 2.

[0080] Comparative Examples 1 to 2:

[0081] The difference between the comparative example and the device example 1 is that the H3 in the organic electroluminescent element is changed to REF-1 and REF-2 known in the industry, and the device performance test data obtained are shown in Table 2. The OLED is characterized by standard methods. For this purpose, the electroluminescent spectrum, current efficiency (measured in cd / A), power efficiency (measured in lm / W) and external quantum efficiency (EQE, measured in %) are determined, which are calculated as a function of luminous density from the current / voltage / luminous density characteristic line (IUL characteristic line) showing Lambertian emission characteristics. EQE1000 means that at 1000 cd / m 2 External quantum efficiency at working brightness, T95 means the device is 1000cd / m 2 The peak and FWHM values ​​represent the working time when the device brightness decreases to 95% at the initial brightness of 1000cd / m 2 The device performances of Examples 1 to 30 of the present invention and Comparative Examples 1 to 2 are summarized in Table 2.

[0082] Table 2

[0083]

[0084]

[0085] Compared with device comparative example 1, the compounds of the present invention exhibit narrow-band orange-red or red light emission in single-host devices (Examples 1-30), mainly because pyrazine, benzopyrazine, cyano-substituted pyrazine, and cyano-substituted benzopyrazine with strong electron-withdrawing effect are introduced into the BN fragment under the premise of maintaining a rigid structure, which shallows the LUMO energy level of the molecule, reduces the energy gap difference of the material, realizes the red shift of the spectrum, and does not cause spectrum broadening. Compared with device comparative example 2, the molecules of the present invention can realize red light emission with only one BN unit, and more steric units can be introduced into the molecule, so the self-quenching effect becomes weaker, so the device efficiency is higher, and therefore the molecular design is more flexible.

Claims

1. A fused heterocyclic compound, It is characterized in that The fused heterocyclic compound is represented by the following general formula 1-4: Among them, X 1 Indicates no bond or single bond; R b1 ~R b4 are each independently a hydrogen atom or a cyano group; R a1 ~R a14 are each independently a hydrogen atom or a substituent; R as a substituent a1 ~R a14 each independently represents: a deuterium atom, a halogen atom, a cyano group, a nitro group, a substituted silicon group, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkene group having 1 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted monovalent heterocyclic group having 5 to 50 ring atoms; R a7 With R a8 and R a10 With R a11 They may be bonded to each other as a group to form a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted monovalent heterocyclic group having 5 to 50 ring atoms.

2. The fused heterocyclic compound according to claim 1, It is characterized in that The R a1 ~R a14 and R b1 ~R b4 The substituent groups are independently: hydrogen atom, deuterium atom, chlorine atom, bromine atom, fluorine atom, cyano group, nitro group, substituted silicon group, substituted or unsubstituted methyl group, substituted or unsubstituted ethyl group, substituted or unsubstituted n-propyl group, substituted or unsubstituted isopropyl group, substituted or unsubstituted n-butyl group, substituted or unsubstituted isobutyl group, substituted or unsubstituted sec-butyl group, substituted or unsubstituted tert-butyl group, substituted or unsubstituted 2-methylbutyl group, substituted or unsubstituted n-pentyl group, substituted or unsubstituted sec-pentyl group, substituted or unsubstituted trifluoromethyl group, substituted substituted or unsubstituted pentafluoroethyl, substituted or unsubstituted 2,2,2-trifluoroethyl, substituted or unsubstituted vinyl, substituted or unsubstituted propenyl, substituted or unsubstituted n-butenyl, substituted or unsubstituted isobutenyl, substituted or unsubstituted n-pentenyl, substituted or unsubstituted isopentenyl, substituted or unsubstituted neopentenyl, substituted or unsubstituted ethynyl, substituted or unsubstituted propynyl, substituted or unsubstituted n-butynyl, substituted or unsubstituted isobutynyl, substituted or unsubstituted n-pentynyl, substituted or unsubstituted isopentenyl substituted or unsubstituted neopentynyl, substituted or unsubstituted cyclopropyl, substituted or unsubstituted cyclobutyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted adamantyl, substituted or unsubstituted thienyl, substituted or unsubstituted indolyl, substituted or unsubstituted furanyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted indenyl, substituted or unsubstituted substituted fluorenyl, substituted or unsubstituted spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted naphthacene, substituted or unsubstituted benzothiazolyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzothiazolyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzoselenophene, substituted or unsubstituted carbazolyl; The R a7 With R a8 and R a10 With R a11 The rings are independently: substituted or unsubstituted cyclopropyl, substituted or unsubstituted cyclobutyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted adamantyl, substituted or unsubstituted thienyl, substituted or unsubstituted indolyl, substituted or unsubstituted furanyl, substituted or unsubstituted phenyl, substituted or unsubstituted pyridyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted indenyl, substituted or unsubstituted substituted or unsubstituted fluorenyl, substituted or unsubstituted spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted naphthacene, substituted or unsubstituted benzothiazolyl, substituted or unsubstituted benzothiophene, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzothiazolyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzoselenophene, substituted or unsubstituted carbazolyl.

3. The fused heterocyclic compound according to claim 1 or 2, It is characterized in that The "substituted" in the "substituted or unsubstituted" in the fused heterocyclic compound means that the substituent is independently a deuterium atom, a tritium atom, a halogen atom, a cyano group, a nitro group, a hydroxyl group, a monovalent alkyl group or a cycloalkyl group having 1 to 10 carbon atoms, a monovalent monocyclic aromatic group or a condensed aromatic group having 6 to 30 carbon atoms, or a monovalent heterocyclic group or a condensed heteroaryl group having 2 to 50 carbon atoms.

4. The fused heterocyclic compound according to any one of claims 1 to 3, It is characterized in that The fused heterocyclic compound is selected from the following structures:

5. An organic electroluminescent element, It is characterized in that The organic electroluminescent element comprises an anode, a cathode and at least one organic thin film located between the anode and the cathode, wherein the organic thin film contains the compound according to any one of claims 1 to 4.

6. The organic electroluminescent element according to claim 5, It is characterized in that The organic film comprises at least one or a combination of at least two of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an exciton blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer, and the light-emitting layer contains the compound according to any one of claims 1 to 4.

7. The organic electroluminescent element according to claim 6, It is characterized in that The compound is used as a light-emitting material in an organic electroluminescent element.

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