An electron transport layer and an organic electroluminescent device

Abstract

The application discloses an electron transport layer and an organic electroluminescent device, and belongs to the technical field of organic electroluminescence. The electron transport layer contains a benzo[e]imidazo[5,1-c][1,2,4] triazine compound. The structure is that an imidazole ring is further introduced on a cinnoline group, the electron transport property of the material is enhanced, and an electron-withdrawing group is matched to adjust the LUMO energy level and the electron injection performance of the compound. The benzo[e]imidazo[5,1-c][1,2,4] triazine compound has higher electron mobility and stronger electron injection capacity, the carrier balance of the device is improved, the luminous efficiency of the device is improved, the efficiency roll-off of the device is reduced, the electron transport layer has good thermal stability, has a longer service life, and can make the starting voltage of the organic electroluminescent device lower.

Description

Technical Field

[0001] This invention relates to an electron transport layer and an organic electroluminescent device, belonging to the field of organic electroluminescence technology. Background Technology

[0002] Organic light-emitting diode (OLED) technology is an active light-emitting technology that uses organic semiconductor thin films under an applied electric field. It boasts numerous advantages, including flexibility, thinness, high brightness, and low power consumption, and is currently widely used in smartphones, televisions, wearable devices, and automotive displays. Organic light-emitting materials are a crucial part of the OLED display technology industry chain and represent a significant technological barrier; therefore, developing high-performance OLED materials is of paramount importance.

[0003] The properties of materials determine the luminescent performance of devices. In OLED devices, the carrier transport characteristics significantly influence the driving voltage, luminous efficiency, and device lifetime. Research on organic transport layer materials has revealed that, compared to electron transport materials, hole transport materials have a higher hole mobility (102...). -2 ~10 -3 cm / V·s) is typically the electron mobility of electron transport materials (10) -4 ~10 -6 The voltage is more than 10 times higher than that of phenanthroline (cm / V·s). This leads to carrier imbalance in the device and significantly increases the driving voltage. To address these issues, researchers have developed a series of phenanthroline and its derivatives as electron transport materials with high electron mobility. However, phenanthroline and its derivatives have a high degree of planarity, resulting in a low glass transition temperature and poor thermal stability, which will affect device lifetime and lead to device instability. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides an electron transport layer and an organic electroluminescent device, aiming to solve the problems of poor electron transport properties and insufficient thermal stability of existing electron transport materials used in organic electroluminescent devices.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] In a first aspect, this application provides an electron transport layer containing a benzo[e]imidazo[5,1-c][1,2,4]triazine compound with the structural formula shown in formula (1):

[0007]

[0008] Wherein, R1 is an electron-withdrawing group of C6 to C30, and is selected from one of phenylcyano and its derivatives, pyridine and its derivatives, pyrimidine and its derivatives, triazine and its derivatives, phenanthroline and its derivatives, imidazole and its derivatives, phosphoroxy and its derivatives, benzo[a]nephrine and its derivatives; L1 is an aryl group of C6 to C30 or a heteroaryl group of C6 to C30.

[0009] The electron transport layer provided in this application has good thermal stability, a longer service life, and high luminous efficiency, which can reduce the start-up voltage of organic electroluminescent devices.

[0010] Preferably, there are 1 to 3 L1s, and they are all selected from one of the following structural formulas:

[0011]

[0012] R3 is a C6-C30 aryl group or a C6-C30 heteroaryl group. Furthermore, each L1 is connected to at least one R1.

[0013] More preferably, R1 is independently represented as one of the following structural formulas:

[0014]

[0015] X, Y, and Z are each independently selected from nitrogen atoms or carbon atoms, and at least one of them contains a nitrogen atom; R4 is selected from aliphatic alkyl chains, alkoxy groups, C6-C30 aryl groups, substituted C6-C30 aryl groups, C2-C30 heteroaryl groups, or substituted C2-C30 heteroaryl groups.

[0016] By designing and introducing electron-withdrawing substituents (R1) and intermediate groups (L1) for transferring electron-withdrawing substituents, the conformation of the compound can be controlled to create a large torsion angle between the substituent and the benzo[e]imidazo[5,1-c][1,2,4]triazine core, thus avoiding significant intermolecular stacking and further improving the thermal stability of the material and enhancing the lifetime stability of the device.

[0017] Preferably, the electron transport layer further contains an n-doper, wherein the benzo[e]imidazo[5,1-c][1,2,4]triazine compound forms an n-doping complex with the n-doper.

[0018] Benzimidazolium compounds can form good n-doping interactions with n-dopersants, thereby improving the electron transport performance of the compounds and n-dopersants.

[0019] In a second aspect, this application provides an organic electroluminescent device, including a substrate and an anode layer, an organic light-emitting functional layer and a cathode layer sequentially disposed on the substrate, wherein the organic light-emitting functional layer contains an electron transport layer as described in the first aspect.

[0020] Preferably, the organic light-emitting functional layer comprises, in sequence from the anode layer to the cathode layer, a hole injection layer, a first hole transport layer, a second hole transport layer, a light-emitting layer, a second electron transport layer, a first electron transport layer, and an electron injection layer. The first electron transport layer is the electron transport layer described in the first aspect. The material of the second electron transport layer is an aromatic ring having a nitrogen-containing six-membered ring skeleton or a nitrogen-containing five-membered ring skeleton, or a fused aromatic ring compound having a nitrogen-containing six-membered ring skeleton or a nitrogen-containing five-membered ring skeleton.

[0021] The beneficial effects of this invention are: the electron transport layer of this invention contains a benzo[e]imidazo[5,1-c][1,2,4]triazine compound, and its gain in organic electroluminescent devices is mainly reflected in:

[0022] (1) By further introducing an imidazo ring onto the boryn group, the electron transport of the material is enhanced. Electron-withdrawing groups are used to adjust the LUMO (Lowest Unoccupied Molecular Orbital) level and electron injection performance of the compound, so that the benzo[e]imidazo[5,1-c][1,2,4]triazine compound has a high electron mobility and strong electron injection capability, improves the carrier (hole and electron) balance of the device, enhances the luminous efficiency of the device, and reduces the efficiency roll-off of the device.

[0023] (2) Further incorporation of imidazole into the boryn group makes it easier for the benzo[e]imidazo[5,1-c][1,2,4]triazine compound to form a good n-doping effect with the n-doper, thereby improving the electron transport performance of the compound and the n-doper composition.

[0024] (3) During the synthesis process, the electron-withdrawing substituents and the intermediate groups that transfer electron-withdrawing substituents can be controlled to regulate the conformation of the compound, so that there is a large torsion angle between the substituent and the benzo[e]imidazo[5,1-c][1,2,4]triazine core, avoiding significant intermolecular stacking of the material, improving the thermal stability of the material, and enhancing the lifespan stability of the device.

[0025] Combining the above three advantages, the organic electroluminescent devices prepared using the benzo[e]imidazo[5,1-c][1,2,4]triazine compound of this application as an electron transport material have the beneficial effects of low driving voltage, high luminous efficiency, and long device life.

[0026] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0027] Figure 1 These are schematic diagrams of the device structures in Embodiments 20 to 31 of this application.

[0028] Reference numerals: 10, anode layer; 11, hole injection layer; 12, first hole transport layer; 13, second hole transport layer; 14, light-emitting layer; 15, second electron transport layer; 16, first electron transport layer; 17, electron injection layer; 18, cathode layer. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this invention.

[0030] It should be understood that, without conflict, any and all embodiments of the present invention can be combined with technical features of any other embodiment or multiple other embodiments to obtain other embodiments. The present invention includes such combinations to obtain other embodiments.

[0031] In this specification, groups and their substituents may be selected by those skilled in the art to provide stable structural moieties and compounds. When a substituent is described by a conventional chemical formula written from left to right, the substituent also includes chemically equivalent substituents obtained when the structural formula is written from right to left.

[0032] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter pertains. Where multiple definitions exist for a term, the definition herein shall prevail.

[0033] This application provides an electron transport layer containing a benzo[e]imidazo[5,1-c][1,2,4]triazine compound with the structural formula shown in formula (1):

[0034]

[0035] Wherein, R1 is an electron-withdrawing group of C6 to C30, and is selected from one of phenylcyano and its derivatives, pyridine and its derivatives, pyrimidine and its derivatives, triazine and its derivatives, phenanthroline and its derivatives, imidazole and its derivatives, phosphoroxy and its derivatives, benzo[a]nephrine and its derivatives; L1 is an aryl group of C6 to C30 or a heteroaryl group of C6 to C30.

[0036] In some embodiments, as a substructure of the compound of formula (1), the benzo[e]imidazo[5,1-c][1,2,4]triazine compound has the structural formula shown in formula (2):

[0037]

[0038] Wherein, when X1 to X4 do not bond with each other to form an aromatic ring or a heteroaromatic ring structure, X1 to X4 represent hydrogen atoms or deuterium atoms; when X1 to X4 bond with each other to form an aromatic ring or a heteroaromatic ring structure, the ring structure contains one or both of carbon atoms and nitrogen atoms; the meaning of R1 is the same as in formula (1).

[0039] In some embodiments, there are 1 to 3 L1s, and they are selected from one of the following structural formulas:

[0040]

[0041] In this equation, the wavy line indicates the position of the ring attached to the cyclophosphamide ring, while the position of the ring attached to R1 is not specified. R3 is a C6-C30 aryl group or a C6-C30 heteroaryl group. In equation (1), L1 is attached to R1, so when there are multiple L1s, each L1 is attached to at least one R1.

[0042] R1 can be independently represented as one of the following structural formulas:

[0043]

[0044] Wherein, X, Y, and Z are each independently selected from nitrogen atoms or carbon atoms, and at least one of the three contains a nitrogen atom; R4 is selected from aliphatic alkyl chains (specifically, methyl, ethyl, tert-butyl), alkoxy (specifically, methoxy), C6-C30 aryl, substituted C6-C30 aryl, C2-C30 heteroaryl, or substituted C2-C30 heteroaryl.

[0045] In some embodiments, the benzo[e]imidazo[5,1-c][1,2,4]triazine compound is selected from any of the structures shown in Formulas 5-1 to 5-53:

[0046]

[0047]

[0048]

[0049]

[0050] In some embodiments, the electron transport layer further contains an n-doper, and the benzo[e]imidazo[5,1-c][1,2,4]triazine compound forms a complex with the n-doper to have an n-doping effect.

[0051] Specifically, the doping concentration of the n-doperant is 0.1% to 30% by mass percentage.

[0052] The preferred n-dopant is selected from at least one of lithium, copper, silver, gold, magnesium, barium, ytterbium, cesium, lithium oxide, copper oxide, silver oxide, gold oxide, magnesium oxide, barium oxide, ytterbium oxide, cesium oxide, lithium carbonate, copper carbonate, silver carbonate, gold carbonate, magnesium carbonate, barium carbonate, ytterbium carbonate, cesium carbonate, lithium 8-hydroxyquinolineate, sodium 8-hydroxyquinolineate, ZnO, and CsN3.

[0053] Next, the organic electroluminescent device of this application will be further described.

[0054] This application provides an organic electroluminescent device, such as... Figure 1 As shown, it includes a substrate and, sequentially disposed on the substrate, an anode layer 10, a hole injection layer 11, a first hole transport layer 12, a second hole transport layer 13, a light-emitting layer 14, a second electron transport layer 15, a first electron transport layer 16, an electron injection layer 17, and a cathode layer 18. The first electron transport layer 16 is the electron transport layer mentioned above containing the benzo[e]imidazo[5,1-c][1,2,4]triazine compound.

[0055] Anode layer 10:

[0056] The anode layer 10 of the organic electroluminescent device primarily functions to inject holes into the hole injection layer 11, the hole transport layer (including the first hole transport layer 12 and the second hole transport layer 13), or the light-emitting layer 14. Preferably, an anode layer material with a work function of 4.5 eV or higher is used. The anode layer material is preferably selected from indium tin oxide (ITO), tin oxide (NESA), indium gallium zinc oxide (IGZO), silver, etc. The anode layer 10 can be formed into a thin film by thermal evaporation, sputtering, or other methods. Preferably, the light transmittance of the visible area of ​​the anode layer 10 is greater than 80%. Furthermore, the sheet resistance of the anode layer 10 is preferably 500 Ω / cm. -1 The film thickness is preferably in the range of 10nm-200nm.

[0057] Cathode layer 18:

[0058] The primary function of the cathode layer 18 in the organic electroluminescent device is to inject electrons into the electron injection layer 17, the electron transport layer (including the second electron transport layer 15 and the first electron transport layer 16), or the light-emitting layer 14. A material with a low work function is preferably used. The cathode layer material is preferably selected from aluminum, magnesium, silver, magnesium-silver alloys, magnesium-aluminum alloys, aluminum-lithium alloys, etc. Similarly, the cathode layer 18 can also be formed into a thin film using methods such as thermal evaporation or sputtering. The film thickness of the cathode layer 18 is preferably in the range of 10 nm to 200 nm. Additionally, light can be extracted from the cathode side as needed.

[0059] Electron injection layer 17:

[0060] The primary function of the electron injection layer 17 is to facilitate the injection of electrons from the cathode layer 18 into the electron transport layer or the light-emitting layer 14, thereby improving the luminous brightness and lifetime of the organic electroluminescent device. Here, the electron injection layer material refers to a material with a work function below 3.8 eV. The electron injection layer material is preferably selected from at least one of the following: lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, gold, silver, copper, iron, nickel, platinum, palladium, ruthenium, ytterbium, molybdenum trioxide, vanadium pentoxide, tungsten trioxide, cesium fluoride, cesium carbonate, lithium fluoride, lithium carbonate, and lithium 8-hydroxyquinoline acid (Liq). The electron injection layer 17 can be formed into a thin film by thermal evaporation, with the evaporation rate preferably being... The thickness of the electron injection layer 17 thus produced is preferably selected in the range of 0.1-15 nm.

[0061] Second electron transport layer 15:

[0062] Its main function is to transport electrons from the first electron transport layer 16 to the light-emitting layer 14. As the electron transport layer material for the second electron transport layer 15, an aromatic heterocyclic compound containing one or more heteroatoms within the molecule is preferred, and a nitrogen-containing ring derivative is particularly preferred. More preferably, the nitrogen-containing ring derivative is an aromatic ring having a nitrogen-containing six-membered ring skeleton or a nitrogen-containing five-membered ring skeleton, or a fused aromatic ring compound having a nitrogen-containing six-membered ring skeleton or a nitrogen-containing five-membered ring skeleton.

[0063] In the embodiments of this application, the second electron transport layer material of the organic electroluminescent device is preferably selected from compounds of formulas (ET-13)-(ET-16) and (ET-45)-(ET-52):

[0064]

[0065] The thickness of the second electron transport layer 15 is preferably 1-30 nm.

[0066] Hole transport layer:

[0067] Its main function is to transport holes from the anode layer to the light-emitting layer 14. The hole transport layer may consist of one organic layer material or two organic layer materials. The organic layer on the side closer to the anode layer 10 is defined as the first hole transport layer 12, and the organic layer on the side closer to the light-emitting layer 14 is defined as the second hole transport layer 13.

[0068] In this embodiment, the hole transport layer material of the organic electroluminescent device may be an aromatic amine compound, preferably a compound of formula (HT-1)-(HT-64):

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075] The hole transport layer thickness is preferably 20-200 nm. Specifically, when the organic electroluminescent device has only one hole transport layer, the thickness is preferably 20 nm-200 nm; when the hole transport layer of the organic electroluminescent device consists of a first hole transport layer and a second hole transport layer, the thickness of the first hole transport layer is preferably 19 nm-150 nm, and the thickness of the second hole transport layer is preferably 1 nm-50 nm.

[0076] Hole injection layer 11:

[0077] The main function of the hole injection layer 11 is to promote the injection of holes from the anode layer 10 to the hole transport layer or the light-emitting layer 14, thereby reducing the driving voltage of the organic electroluminescent device and improving its brightness and lifetime. Here, the hole injection layer material refers to a material formed by combining a acceptor-type p-type dopant containing a deep LUMO energy level with a hole transport material. The hole transport material is preferably a compound of formulas (HT-1) to (HT-64). As a specific example, the p-type dopant can preferably be one of HI-1 to HI-20, and the film thickness of the hole injection layer 11 is preferably in the range of 1 nm to 50 nm.

[0078] The structural formula of HI-1-HI-20 is shown below:

[0079]

[0080]

[0081] The present application will be further illustrated below with specific examples. Examples 1 to 8 illustrate the specific details of the synthesis experiments. Examples 20 to 31 illustrate the specific details of the preparation of organic electroluminescent devices. Comparative Examples 40 to 44 are compared with Examples 20 to 31.

[0082] Example 1

[0083] The synthesis path is as follows:

[0084]

[0085] Wherein, DMSO represents dimethyl sulfoxide; Pd(PPh3)4 represents tetrakis(triphenylphosphine)palladium; THF represents tetrahydrofuran; EtOH represents ethanol; HOAc represents acetic acid; and MeCN represents acetonitrile.

[0086] Under a nitrogen atmosphere, 1-bromo-3-fluoro-2-nitrobenzene (P-1) (5.31 g, 24.13 mmol, 1.00 Eq) and imidazole (1.64 g, 24.13 mmol, 1.00 Eq) were dissolved in DMSO (25 mL). NaOH (1.45 g, 36.20 mmol, 1.50 Eq) was slowly added with stirring. The mixture was stirred for 2 hours and then diluted with water (100 mL). The aqueous phase was extracted with EtOAc (3 times x 100 mL). Saturated brine was added to the extract to promote separation of the organic and aqueous phases. The resulting organic phase was then dried over MgSO4 and evaporated to dryness to obtain a white solid product, P-3, with a yield of 6.47 g (85%).

[0087] Under a nitrogen atmosphere, a stir bar, P-3 (6.17 g, 23.00 mmol, 1.00 Eq), 4-bromophenylboronic acid (P-4) (5.08 g, 25.30 mmol, 1.10 Eq), Pd(PPh3)4 (1.33 g, 1.15 mmol, 0.05 Eq), and K2CO3 (6.99 g, 50.60 mmol, 2.20 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was then extracted with EtOAc (2 x 50 mL), the combined organic phases were washed with brine and dried, and after evaporation of all volatiles, the orange oil was separated, which could be used in the next step without further purification. Analytical grade sample P-5 was obtained by column chromatography, yielding 5.48 g, 75% yield.

[0088] Under a nitrogen atmosphere, P-5 (7.60 g, 22.08 mmol, 1.00 Eq) and iron powder (6.17 g, 55.85 mmol, 5.00 Eq) were added to a round-bottom flask. EtOH (50 mL) and HOAc (50 mL) were added, and the reaction was continued for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 mL) and neutralized with 12% hydrochloric acid, then adjusted to pH 8 with K₂CO₃ buffer solution. The aqueous layer was extracted with CH₂Cl₂ (3 x 100 mL), the organic phases were combined, washed with brine, and dried over MgSO₄. After evaporation of all volatiles, the mixture was passed through a rapid column chromatography column (SiO₂, CH₂Cl₂:MeOH = 95:5) to obtain P-6, yielding 6.47 g (95% yield).

[0089] Under a nitrogen atmosphere, in a round-bottom flask, powdered P-6 (1104 mg, 3.51 mmol, 1.00 Eq) was treated with MeCN (10 mL) and HCl (aqueous solution) (1.5 mL) and concentrated. The resulting red mixture was cooled to -15 °C. An aqueous solution of NaNO2 (5 mL) was added dropwise with stirring. The resulting yellow mixture was heated to 0 °C and stirred for 30 minutes. The mixture was recooled to -15 °C, and a water / MeCN mixture (5 mL / 5 mL) was added dropwise. The mixture was stirred overnight at room temperature. After the reaction, a buffer solution of K2CO3 was added to adjust the pH to 8, and the mixture was extracted with CH2Cl2 (twice x 30 mL). The combined extracts were washed with dilute sulfuric acid. The mixture was then washed successively with NaS2O3 (aq) and saturated brine and dried over MgSO4. After evaporation of all volatiles, the crude product was purified by column chromatography (SiO2, cyclohexane / EtOAc = 1 / 3) to obtain a brown solid. Recrystallization from CH2Cl2 yielded lemon-colored crystals P-7, with a yield of 260 mg and a recovery rate of 23%.

[0090] Under a nitrogen atmosphere, a stir bar, P-7 (3.25 g, 10.00 mmol, 1.00 Eq), 2,4-diphenyl-6-pinacol ester-1,3,5-triazine (P-8, 5.59 g, 10.30 mmol, 1.10 Eq), K₂CO₃ (6.99 g, 50.60 mmol, 2.20 Eq), and Pd(PPh₃)₄ (1.33 g, 1.15 mmol, 0.05 Eq) were added to a Schlenk flask. THF (50 ml) and deoxygenated water (25 ml) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was then extracted with EtOAc (2 x 50 ml), the organic phases were combined, washed with brine, and dried. After evaporation of all volatiles, the orange oil was separated. Analytical grade sample 5-1 was obtained by column chromatography, with a yield of 2.48 g and a yield of 79%.

[0091] Example 2

[0092] The synthesis path is as follows:

[0093]

[0094] Under a nitrogen atmosphere, a stir bar, P-3 (6.17 g, 23.00 mmol, 1.00 Eq), 2-bromophenylboronic acid (P-9, 5.08 g, 25.30 mmol, 1.10 Eq), Pd(PPh3)4 (1.33 g, 1.15 mmol, 0.05 Eq), and K2CO3 (6.99 g, 50.60 mmol, 2.20 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (2 x 50 mL), the organic phases were combined, washed with brine, dried, and after evaporation of all volatiles, the orange oil was separated, which could be used in the next step without further purification. Analytical grade sample P-10 was obtained by column chromatography, yielding 4.98 g, with a yield of 64%.

[0095] Under a nitrogen atmosphere, P-10 (7.60 g, 22.08 mmol, 1.00 Eq) and iron powder (6.17 g, 55.85 mmol, 5.00 Eq) were added to a round-bottom flask. EtOH (50 mL) and HOAc (50 mL) were added, and the reaction was continued for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 mL) and neutralized with 12% hydrochloric acid, then adjusted to pH 8 with K₂CO₃ buffer solution. The aqueous layer was extracted with CH₂Cl₂ (3 times x 100 mL), and the combined organic phases were washed with brine and dried over MgSO₄. After evaporation of all volatiles, P-11 was obtained by rapid column chromatography (SiO₂, CH₂Cl₂:MeOH = 95:5) to obtain a yield of 6.48 g (92%).

[0096] Powdered P-11 (1104 mg, 3.51 mmol, 1.00 Eq) was treated with MeCN (10 mL) and HCl (1.5 mL aqueous solution) and concentrated in a round-bottom flask under a nitrogen atmosphere. The resulting red mixture was cooled to -15 °C. An aqueous solution of NaNO2 (5 mL) was added dropwise with stirring. The resulting yellow mixture was heated to 0 °C and stirred for 30 minutes. The mixture was recooled to -15 °C, and a water / MeCN mixture (5 mL / 5 mL) was added dropwise. The mixture was stirred overnight at room temperature. The reaction was neutralized with dilute sulfuric acid. The pH was adjusted to 8 with a buffer solution of K2CO3, and the mixture was extracted with CH2Cl2 (twice x 30 mL). The combined extracts were washed with concentrated sulfuric acid. The mixture was washed with NaS2O3 (aq) and saturated brine and dried over MgSO4. After evaporation of all volatiles, the crude product was purified by column chromatography (SiO2, cyclohexane / EtOAc = 1 / 3) to obtain a brown solid. Recrystallization from CH2Cl2 yielded lemon-colored crystals P-12, with a yield of 220 mg and a recovery rate of 18%.

[0097] Under a nitrogen atmosphere, a stir bar, P-12 (3.25 g, 10.00 mmol, 1.00 Eq), 2,4-diphenyl-6-pinacol ester-1,3,5-triazine (P-8, 5.59 g, 10.30 mmol, 1.10 Eq), K₂CO₃ (6.99 g, 50.60 mmol, 2.20 Eq), and Pd(PPh₃)₄ (1.33 g, 1.15 mmol, 0.05 Eq) were added to a Schlenk flask. THF (50 ml) and deoxygenated water (25 ml) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (twice x 50 ml), the combined organic phases were washed with brine and dried, and the orange oil was separated after evaporation of all volatiles. Analytical grade sample 5-8 was obtained by column chromatography, with a yield of 2.38 g and a yield of 76%.

[0098] Example 3

[0099] The synthesis path is as follows:

[0100]

[0101] Under nitrogen protection, intermediate P-12 (6.28 g, 20 mmol, 1 eq), bis(pinarate)diborane (7.62 g, 30 mmol, 1.5 eq), potassium acetate (KOAC, 5.88 g, 60 mmol, 3 eq), [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride (Pd(dppf)Cl2, 438.6 mg, 0.6 mmol, 0.03 eq), and 120 mL of dioxane were placed in a round-bottom flask. The mixture was heated at 85 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed three times with 50 mL of water and extracted with dichloromethane. The organic solution was dried over MgSO4 to evaporate the solvent. The residue was mixed with silica gel powder and purified by column chromatography (developing solvent: petroleum ether / dichloromethane = 1:2) to give a white solid intermediate P-13, yielding 5.5 g (86% yield).

[0102] Under nitrogen protection, P-13 (3.72 g, 10.00 mmol, 1.00 Eq), P-14 (3.73 g, 10.30 mmol, 1.10 Eq), K₂CO₃ (4.14 g, 30 mmol, 3 Eq) and Pd(PPh₃)₄ (0.346 g, 0.3 mmol, 0.03 Eq) were mixed. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. Heating was stopped after complete consumption of the starting intermediate P-13 by TLC (thin-layer chromatography). After cooling to room temperature, the reaction solution was washed with water until neutral. The organic phase was dried over anhydrous sodium sulfate and purified by silica gel column chromatography to give compound 5-15, yield 2.89 g, 74.8%.

[0103] Example 4

[0104] The synthesis path is as follows:

[0105]

[0106] Under nitrogen protection, P-8 (3.59 g, 10.00 mmol, 1.00 Eq), P-16 (2.60 g, 10.30 mmol, 1.10 Eq), K₂CO₃ (4.14 g, 30 mmol, 3 Eq) and Pd(PPh₃)₄ (0.346 g, 0.3 mmol, 0.03 Eq) were mixed. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. Heating was stopped after TLC monitoring showed complete consumption of the starting intermediate P-16. After cooling to room temperature, the reaction solution was washed with water until neutral. The organic phase was dried over anhydrous sodium sulfate and purified by silica gel column chromatography to give compound P-17, yield 2.55 g, 78.9%.

[0107] Under nitrogen protection, P-17 (3.59 g, 10.00 mmol, 1.00 Eq), P-13 (2.60 g, 10.30 mmol, 1.10 Eq), K₂CO₃ (4.14 g, 30 mmol, 3 Eq) and Pd(PPh₃)₄ (0.346 g, 0.3 mmol, 0.03 Eq) were mixed. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. Heating was stopped after TLC monitoring showed complete consumption of the starting intermediate P-13. After cooling to room temperature, the reaction solution was washed with water until neutral. The organic phase was dried over anhydrous sodium sulfate and purified by silica gel column chromatography to give compound 5-23, yield 2.45 g, 74.9%.

[0108] Example 5

[0109] The synthesis path is as follows:

[0110]

[0111] Under a nitrogen atmosphere, 1-bromo-4-fluoro-3-nitrobenzene (P-18, 5.31 g, 24.13 mmol, 1.00 Eq) and imidazole (1.64 g, 24.13 mmol, 1.00 Eq) were dissolved in DMSO (25 mL). NaOH (1.45 g, 36.20 mmol, 1.50 Eq) was slowly added with stirring. The mixture was stirred for 2 hours and then diluted with water (100 mL). The aqueous phase was extracted with EtOAc (3 x 100 mL). Saturated brine was added to the extract to promote separation of the organic and aqueous phases. The resulting organic phase was then dried over MgSO4 and evaporated to dryness to obtain a white solid product, P-19, with a yield of 6.37 g (83%).

[0112] Under a nitrogen atmosphere, a stir bar, P-19 (6.17 g, 23.00 mmol, 1.00 Eq), 4-bromophenylboronic acid (P-4, 5.08 g, 25.30 mmol, 1.10 Eq), Pd(PPh3)4 (1.33 g, 1.15 mmol, 0.05 Eq), and K2CO3 (6.99 g, 50.60 mmol, 2.20 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (2 x 50 mL), the combined organic phases were washed with brine and dried, and after evaporation of all volatiles (which could be used in the next step without further purification), the sample P-20 was purified by column chromatography to obtain analytical grade sample P-20, yield 5.35 g, 73% yield.

[0113] Under a nitrogen atmosphere, P-20 (7.60 g, 22.08 mmol, 1.00 Eq) and iron powder (6.17 g, 55.85 mmol, 5.00 Eq) were added to a round-bottom flask. EtOH (50 mL) and HOAc (50 mL) were added, and the reaction continued for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 mL) and neutralized with 12% hydrochloric acid, then adjusted to pH 8 with K₂CO₃ buffer solution. The aqueous layer was extracted with CH₂Cl₂ (3 times x 100 mL), and the combined organic phases were washed with brine and dried over MgSO₄. After evaporation of all volatiles, P-21 was obtained by rapid column chromatography (SiO₂, CH₂Cl₂ / MeOH ratio 95:5) to obtain a yield of 6.54 g (97%).

[0114] Under a nitrogen atmosphere, in a round-bottom flask, powdered P-21 (1104 mg, 3.51 mmol, 1.00 Eq) was treated with MeCN (10 mL) and HCl (1.5 mL aqueous solution) and concentrated. The resulting red mixture was cooled to -15 °C. An aqueous solution of NaNO2 (5 mL) was added dropwise with stirring. The resulting yellow mixture was heated to 0 °C and stirred for 30 minutes. The mixture was recooled to -15 °C, and water / MeCN (5 mL / 5 mL) was added dropwise. The mixture was stirred overnight at room temperature. After the reaction, the mixture was neutralized with dilute sulfuric acid. The pH was adjusted to 8 with a buffer solution of K2CO3, and the mixture was extracted with CH2Cl2 (twice x 30 mL). The combined extracts were washed with concentrated sulfuric acid. The mixture was then washed successively with NaS2O3 (aq) and saturated brine, and dried over MgSO4. After evaporation of all volatiles, the crude product was purified by column chromatography (SiO2, cyclohexane / EtOAc = 1 / 3) to obtain a brown solid. Recrystallization from CH2Cl2 yielded lemon-colored crystals P-22, with a yield of 170 mg and a recovery rate of 17%.

[0115] Under nitrogen protection, intermediate P-22 (6.50 g, 20 mmol, 1 eq), bis(pinarate)diborane (7.62 g, 30 mmol, 1.5 eq), potassium acetate (KOAC, 5.88 g, 60 mmol, 3 eq), DPPF palladium dichloride (Pd(dppf)Cl2, 438.6 mg, 0.6 mmol, 0.03 eq), and solvent 120 mL of dioxane were placed in a round-bottom flask. The mixture was heated at 85 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed three times with 50 mL of water and extracted with dichloromethane. The organic solution was dried over MgSO4 to evaporate the solvent. The residue was mixed with silica gel powder and purified by column chromatography (developing solvent: petroleum ether / dichloromethane = 1:2) to give a white solid intermediate P-23, yielding 5.2 g (79%).

[0116] Under a nitrogen atmosphere, a stir bar, P-23 (3.25 g, 10.00 mmol, 1.00 Eq), P-24 (7.96 g, 10.30 mmol, 1.10 Eq), K₂CO₃ (6.99 g, 50.60 mmol, 2.20 Eq), and Pd(PPh₃)₄ (1.33 g, 1.15 mmol, 0.05 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (2 x 50 mL), the combined organic phases were washed with brine and dried, and after evaporation of all volatiles, the orange oil was separated, which could be used in the next step without further purification. Analytical purity sample 5-29 was obtained by column chromatography, yielding 8.86 g, with a yield of 63%.

[0117] Example 6

[0118] The synthesis path is as follows:

[0119]

[0120] Under a nitrogen atmosphere, a stir bar, P-19 (6.17 g, 23.00 mmol, 1.00 Eq), 1,3-dibromophenylboronic acid (P-25, 6.98 g, 25.30 mmol, 1.10 Eq), Pd(PPh3)4 (1.33 g, 1.15 mmol, 0.05 Eq), and K2CO3 (6.99 g, 50.60 mmol, 2.20 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (2 x 50 mL), and the combined organic phases were washed with brine and dried. After evaporation of all volatiles, the mixture could be used in the next step without further purification. Analytical grade sample P-26 was obtained by column chromatography, yielding 5.73 g, with a yield of 71%.

[0121] Under a nitrogen atmosphere, P-26 (9.33 g, 22.08 mmol, 1.00 Eq) and iron powder (6.24 g, 110.4 mmol, 5.00 Eq) were added to a round-bottom flask. EtOH (50 mL) and HOAc (50 mL) were added, and the reaction was continued for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 mL) and neutralized with 12% hydrochloric acid, then adjusted to pH 8 with K₂CO₃ buffer solution. The aqueous layer was extracted with CH₂Cl₂ (3 times x 100 mL), and the combined organic phases were washed with brine and dried over MgSO₄. After evaporation of all volatiles, the mixture was passed through a rapid column chromatography column (SiO₂, CH₂Cl₂:MeOH = 95:5) to obtain P-27, yielding 7.56 g (93% yield).

[0122] Under a nitrogen atmosphere, in a round-bottom flask, powdered P-27 (1304 mg, 3.51 mmol, 1.00 Eq) was treated with MeCN (10 mL) and HCl (1.5 mL aqueous solution) and concentrated. The resulting red mixture was cooled to -15 °C. An aqueous solution of NaNO2 (5 mL) was added dropwise with stirring. The resulting yellow mixture was heated to 0 °C and stirred for 30 minutes. The mixture was recooled to -15 °C, and water / MeCN (5 mL / 5 mL) was added dropwise again. The mixture was stirred overnight at room temperature. After the reaction, the mixture was neutralized with dilute sulfuric acid. The pH was adjusted to 8 with a buffer solution of K2CO3, and the mixture was extracted with CH2Cl2 (twice x 30 mL). The combined extracts were washed with concentrated sulfuric acid. The mixture was then washed successively with NaS2O3 (aq) and saturated brine and dried over MgSO4. After evaporation of all volatiles, the crude product was purified by column chromatography (SiO2, cyclohexane / EtOAc = 1 / 3) to obtain a brown solid. Recrystallization from CH2Cl2 yielded lemon-colored crystals P-28, with a yield of 210 mg and a recovery rate of 18%.

[0123] Under nitrogen protection, intermediate P-28 (8.50 g, 20 mmol, 1 eq), bis(pinarate)diborane (7.62 g, 30 mmol, 1.5 eq), potassium acetate (KOAC, 5.88 g, 60 mmol, 3 eq), DPPF palladium dichloride (Pd(dppf)Cl2, 438.6 mg, 0.6 mmol, 0.03 eq), and solvent 120 mL of dioxane were placed in a round-bottom flask. The mixture was heated at 85 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed three times with 50 mL of water and extracted with dichloromethane. The organic solution was dried over MgSO4 to evaporate the solvent. The residue was mixed with silica gel powder and purified by column chromatography (developing solvent: petroleum ether / dichloromethane = 1:2) to give a white solid intermediate P-29, yielding 5.8 g (81%).

[0124] Under a nitrogen atmosphere, a stir bar, P-29 (3.25 g, 10.00 mmol, 1.00 Eq), P-30 (5.18 g, 20.30 mmol, 1.10 Eq), K₂CO₃ (13.99 g, 100.60 mmol, 4.40 Eq), and Pd(PPh₃)₄ (2.33 g, 2.15 mmol, 1 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (2 x 50 mL), the combined organic phases were washed with brine and dried, and the orange oil was separated after evaporation of all volatiles. Analytical purity sample 5-41 was obtained by column chromatography, yielding 5.83 g (67% yield).

[0125] Example 7

[0126] The synthesis path is as follows:

[0127]

[0128] Under a nitrogen atmosphere, a stir bar, P-19 (6.17 g, 23.00 mmol, 1.00 Eq), 2-bromophenylboronic acid (P-9, 5.08 g, 25.30 mmol, 1.10 Eq), Pd(PPh3)4 (1.33 g, 1.15 mmol, 0.05 Eq), and K2CO3 (6.99 g, 50.60 mmol, 2.20 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (twice x 50 mL), and the combined organic phases were washed with brine and dried. After evaporation of all volatiles, the mixture could be used in the next step without further purification. Analytical grade sample P-31 was obtained by column chromatography, yielding 5.64 g, 75% yield.

[0129] Under a nitrogen atmosphere, P-31 (7.60 g, 22.08 mmol, 1.00 Eq) and iron powder (12.17 g, 110.56 mmol, 5.00 Eq) were added to a round-bottom flask. EtOH (50 mL) and HOAc (50 mL) were added, and the reaction was continued for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 mL) and neutralized with 12% hydrochloric acid, then adjusted to pH 8 with K₂CO₃ buffer solution. The aqueous layer was extracted with CH₂Cl₂ (3 times x 100 mL), and the combined organic phases were washed with brine and dried over MgSO₄. After evaporation of all volatiles, the mixture was subjected to rapid column chromatography (SiO₂, CH₂Cl₂:MeOH = 95:5) to obtain P-32, yielding 5.96 g (91% yield).

[0130] Under a nitrogen atmosphere, in a round-bottom flask, powdered P-32 (1104 mg, 3.51 mmol, 1.00 Eq) was treated with MeCN (10 mL) and HCl (1.5 mL aqueous solution) and concentrated. The resulting red mixture was cooled to -15 °C. An aqueous solution of NaNO2 (5 mL) was added dropwise with stirring. The resulting yellow mixture was heated to 0 °C and stirred for 30 minutes. The mixture was recooled to -15 °C, and water / MeCN (5 mL / 5 mL) was added dropwise. The mixture was stirred overnight at room temperature. After the reaction, the mixture was neutralized with dilute sulfuric acid. The pH was adjusted to 8 with a buffer solution of K2CO3, and the mixture was extracted with CH2Cl2 (twice x 30 mL). The combined extracts were washed with concentrated sulfuric acid. The mixture was then washed successively with NaS2O3 (aq) and saturated brine and dried over MgSO4. After evaporation of all volatiles, the crude product was purified by column chromatography (SiO2, cyclohexane / EtOAc = 1 / 3) to obtain a brown solid. Recrystallization from CH2Cl2 yielded lemon-colored crystals P-33, with a yield of 250 mg and a recovery rate of 23%.

[0131] Under nitrogen protection, intermediate P-33 (6.50 g, 20 mmol, 1 eq), bis(pinarate)diborane (7.62 g, 30 mmol, 1.5 eq), potassium acetate (KOAC, 5.88 g, 60 mmol, 3 eq), DPPF palladium dichloride (Pd(dppf)Cl2, 438.6 mg, 0.6 mmol, 0.03 eq), and solvent 120 mL of dioxane were placed in a round-bottom flask. The mixture was heated at 85 °C under nitrogen for 48 hours. After cooling to room temperature, the mixture was washed three times with 50 mL of water and extracted with dichloromethane. The organic solution was dried over MgSO4 to evaporate the solvent. The residue was mixed with silica gel powder and purified by column chromatography (developing solvent: petroleum ether / dichloromethane = 1:2) to give a white solid intermediate P-34, yielding 7.8 g (73% yield).

[0132] Under a nitrogen atmosphere, a stir bar, P-34 (3.25 g, 10.00 mmol, 1.00 Eq), P-8 (7.96 g, 10.30 mmol, 1.10 Eq), K₂CO₃ (6.99 g, 50.60 mmol, 2.20 Eq), and Pd(PPh₃)₄ (1.33 g, 1.15 mmol, 0.05 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (twice x 50 mL), the combined organic phases were washed with brine and dried, and the orange oil was separated after evaporation of all volatiles. Analytical purity sample 5-52 was obtained by column chromatography, yielding 8.63 g, with a yield of 61%.

[0133] Example 8

[0134] The synthesis path is as follows:

[0135]

[0136] Under a nitrogen atmosphere, 1-bromo-4-fluoro-3-nitrobenzene (P-35, 5.31 g, 24.13 mmol, 1.00 Eq) and imidazole (1.64 g, 24.13 mmol, 1.00 Eq) were dissolved in DMSO (25 mL). NaOH (1.45 g, 36.20 mmol, 1.50 Eq) was slowly added with stirring. The mixture was stirred for 2 hours and then diluted with water (100 mL). The aqueous phase was extracted with EtOAc (3 times x 100 mL). The combined organic phases were washed with brine, dried over MgSO4, and evaporated to dryness to obtain a white solid product, P-36, in a yield of 6.72 g (86%).

[0137] Under a nitrogen atmosphere, a stir bar, P-36 (6.17 g, 23.00 mmol, 1.00 Eq), 2-bromophenylboronic acid (P-9, 5.08 g, 25.30 mmol, 1.10 Eq), Pd(PPh3)4 (1.33 g, 1.15 mmol, 0.05 Eq), and K2CO3 (6.99 g, 50.60 mmol, 2.20 Eq) were added to a Schlenk flask. THF (50 mL) and deoxygenated water (25 mL) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (2 x 50 mL), the combined organic phases were washed with brine and dried, and after evaporation of all volatiles, the orange oil was separated, which could be used in the next step without further purification. Analytical grade sample P-37 was obtained by column chromatography, yielding 5.32 g, 72% yield.

[0138] Under a nitrogen atmosphere, P-37 (7.60 g, 22.08 mmol, 1.00 Eq) and iron powder (12.17 g, 110.85 mmol, 5.00 Eq) were added to a round-bottom flask. EtOH (50 mL) and HOAc (50 mL) were added, and the reaction was continued for 3 hours. After cooling to room temperature, the mixture was diluted with water (100 mL) and neutralized with 12% hydrochloric acid, then adjusted to pH 8 with K₂CO₃ buffer solution. The aqueous layer was extracted with CH₂Cl₂ (3 times x 100 mL), and the combined organic phases were washed with brine and dried over MgSO₄. After evaporation of all volatiles, the mixture was passed through a rapid column chromatography column (SiO₂, CH₂Cl₂:MeOH = 95:5) to obtain P-38, yielding 6.47 g (95% yield).

[0139] Under a nitrogen atmosphere, in a round-bottom flask, powdered P-38 (1104 mg, 3.51 mmol, 1.00 Eq) was treated with MeCN (10 mL) and HCl (aqueous solution) (1.5 mL) and concentrated. The resulting red mixture was cooled to -15 °C. An aqueous solution of NaNO2 (5 mL) was added dropwise with stirring. The resulting yellow mixture was heated to 0 °C and stirred for 30 minutes. The mixture was recooled to -15 °C, and water / MeCN (5 mL / 5 mL) was added dropwise. The mixture was stirred overnight at room temperature. After the reaction, the mixture was neutralized with dilute sulfuric acid. The pH was adjusted to 8 with a buffer solution of K2CO3, and the mixture was extracted with CH2Cl2 (2 x 30 mL). The combined extracts were washed with concentrated sulfuric acid. The mixture was then washed successively with NaS2O3 (aq) and saturated brine and dried over MgSO4. After evaporation of all volatiles, the crude product was purified by column chromatography (SiO2, cyclohexane / EtOAc = 1 / 3) to obtain a brown solid. Recrystallization from CH2Cl2 yielded lemon-colored crystals P-39, with a yield of 250 mg and a recovery rate of 22%.

[0140] Under a nitrogen atmosphere, a stir bar, P-39 (3.25 g, 10.00 mmol, 1.00 Eq), 2,4-diphenyl-6-pinacol ester-1,3,5-triazine (P-8, 5.59 g, 10.30 mmol, 1.10 Eq), K₂CO₃ (6.99 g, 50.60 mmol, 2.20 Eq), and Pd(PPh₃)₄ (1.33 g, 1.15 mmol, 0.05 Eq) were added to a Schlenk flask. THF (50 ml) and deoxygenated water (25 ml) were added, and the mixture was stirred and refluxed for 18 hours. The mixture was cooled to room temperature and filtered through a Celite stopper. The stopper was extracted with EtOAc (2 x 50 ml), the combined organic phases were washed with brine and dried. After evaporation of all volatiles, the orange oil was separated. Analytical grade sample 5-53 was obtained by column chromatography, with a yield of 2.36 g and a yield of 78%.

[0141] The elemental analysis and molecular weight of the compounds prepared in Examples 1-8 are shown in Table 1.

[0142] Table 1. Elemental analysis and molecular weight results of the compounds.

[0143] 5-1 C, 75.44; H, 4.02; N, 20.54 477.26 5-8 C, 75.50; H, 4.00; N, 20.50 477.23 5-15 C, 80.22; H, 4.15; N, 15.63 538.12 5-23 C, 76.85; H, 3.84; N, 19.31 578.30 5-29 C, 80.80; H, 4.27; N, 14.92 564.22 5-41 C, 77.83; H, 3.67; N, 18.50 602.10 5-52 C, 75.47; H, 4.02; N, 20.51 477.29 5-53 C, 75.45; H, 4.00; N, 20.55 477.17

[0144] The glass transition temperature and decomposition temperature of compounds 5-1, 5-8, 5-52, 5-53, and comparative compounds 3 and 4 were tested.

[0145]

[0146] The test results are shown in Table 2.

[0147] Table 2 shows the glass transition temperature and decomposition temperature of the compounds.

[0148]

[0149] The following are examples of organic electroluminescent devices prepared using the compounds of this application. The specific device fabrication process and device performance testing experiments are as follows:

[0150] A 30mm × 30mm × 0.7mm glass substrate with an ITO transparent electrode (anode layer, ITO film thickness 160nm, commercially available, not detailed here) was sequentially ultrasonically cleaned in a cleaning solution (1 time), acetone (1 time), ultrapure water (2 times), and isopropanol (1 time), with each ultrasonic cleaning step lasting 10 minutes. The cleaned ITO glass substrate was then baked in an oven at 80℃ for 3 hours. The cleaning solution was used to remove dirt and oil adhering to the surface of the glass substrate with the ITO transparent electrode.

[0151] The baked glass substrate with ITO transparent electrodes was subjected to vacuum plasma cleaning for 10 minutes.

[0152] The plasma-treated glass substrate is mounted on the substrate holder of the vacuum evaporation apparatus. First, compounds HI-6 and (HT-10) are co-deposited on the side where the ITO transparent electrode is formed. The doping concentration of compound HI-6 is 3wt%, forming a hole injection layer 11 with a film thickness of 10nm.

[0153] A compound (HT-10) is deposited on top of the hole injection layer to form a first hole transport layer 12 with a thickness of 30 nm.

[0154] Subsequently, a compound (HT-64) is deposited on the first hole transport layer to form a second hole transport layer 13 with a film thickness of 10 nm.

[0155] Subsequently, GH (host material) and GD (dopant material) are co-deposited on the second hole transport layer, with the doping concentration of compound GD being 3wt%, forming a light-emitting layer 14 with a film thickness of 40nm. The structural formulas of GH and GD are as follows:

[0156]

[0157] Subsequently, an ET-46 vapor deposition was performed on the light-emitting layer to form a second electron transport layer 15 with a thickness of 10 nm.

[0158] Subsequently, a second compound, benzo[e]imidazo[5,1-c][1,2,4]triazine, and a first compound, n, are deposited on the second electron transport layer to form a first electron transport layer 16 with a film thickness of 30 nm. The combination of the second compound and the first compound and their mass are shown in Table 3 below.

[0159] Table 3. Material composition of the second electron transport layer in Examples 20-31

[0160] 20 5-1 Silver (10%) 21 5-8 Silver (10%) 22 5-15 Silver (10%) 23 5-23 Silver (10%) 24 5-29 Silver (10%) 25 5-41 Silver (10%) 26 5-52 Silver (10%) 27 5-53 Silver (10%) 28 5-1 - 29 5-8 - 30 5-8 Ytterbium (1%) 31 5-8 Gold (10%)

[0161] Subsequently, ytterbium is deposited on the first electron transport layer to form an electron injection layer 17 with a thickness of 2 nm.

[0162] Subsequently, metal Al is deposited on the electron injection layer to form a cathode layer 18 with a film thickness of 100 nm, thus obtaining an organic electroluminescent device.

[0163] Comparative Examples 40-44

[0164] The organic electroluminescent devices prepared in Comparative Examples 40-44 are the same as those in Examples 20-31, except for the second electron transport layer. The second electron transport layer in Comparative Examples 40-44 is prepared by co-evaporation of the second compound and the first compound. The combination of the second compound and the first compound and their mass are shown in Table 4.

[0165] Table 4. Material composition of the second electron transport layer in Comparative Examples 40-44

[0166] 40 Compare compound 1 - 41 Compare compound 2 - 42 Compare compound 3 - 43 Compare compound 4 - 44 Compare compound 4 Silver (10%)

[0167] Comparative compound 1 and comparative compound 2 have the following structural formulas:

[0168]

[0169] The organic electroluminescent devices prepared in Examples 20-31 and Comparative Examples 40-44 of this application were measured using a spectroradiometer CS-2000 (Konica Minolta) and a digital source meter 2420 (Keithley) at 10 mA / cm². 2 External quantum efficiency (%) at current density, driving voltage (V), and T95 (time required for brightness to decay to 95% of initial brightness) lifetime (hours).

[0170] The performance results of the organic electroluminescent devices prepared in Examples 20-31 and Comparative Examples 40-44 of this application are shown in Table 5.

[0171] Table 5 Performance results of the organic electroluminescent devices prepared in Examples 20-31 and Comparative Examples 40-44

[0172]

[0173]

[0174] Combining the device performance results of Examples 28-29 and Comparative Examples 40-42 in Comparative Table 5, it can be seen that the benzo[e]imidazo[5,1-c][1,2,4]triazine compound of this application exhibits a lower device driving voltage and a longer device lifetime compared to the organic electroluminescent devices prepared by comparative compounds 1-3. This is because the benzo[e]imidazo[5,1-c][1,2,4]triazine unit of the compound of this application has a nitrogen heterocyclic structure, which has good electron transport properties, making it easier for electrons from the device cathode to be injected into the light-emitting layer, thus reducing the device driving voltage. On the other hand, the benzo[e]imidazo[5,1-c][1,2,4]triazine compound has better thermal and chemical stability compared to comparative compounds 1-4, which improves the device lifetime. Comparing the device performance results of Examples 20-27 and Comparative Examples 43-44 in Table 5, it can be seen that when the benzo[e]imidazo[5,1-c][1,2,4]triazine compound is further combined with an n-doper to form an electron transport composition, the driving voltage of the device is further reduced. Furthermore, the complex formed by the benzo[e]imidazo[5,1-c][1,2,4]triazine compound and the n-doper further improves the stability of the electron transport material, thus increasing the device lifetime. Comparing the glass transition temperature and decomposition temperature of Examples 1, 2, 7, and 8 in Table 2, it can be seen that the electron-withdrawing group at the ortho position of the benzo[e]imidazo[5,1-c][1,2,4]triazine exhibits better thermal stability compared to materials with other site-attached groups. Continuing to compare the device performance results of Examples 20, 21, 26, and 27, the improvement in material thermal stability leads to a simultaneous increase in device lifetime.

[0175] Overall, the benzo[e]imidazo[5,1-c][1,2,4]triazine compound of this application has better electron transport properties and good chemical stability as an electron transport material. The organic electroluminescent device prepared by it achieves device performance with low driving voltage, high efficiency and long lifetime.

[0176] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0177] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An organic electroluminescent device, comprising a substrate and an anode layer, an organic light-emitting functional layer, and a cathode layer sequentially disposed on the substrate, wherein the organic light-emitting functional layer includes an electron transport layer, characterized in that, The electron transport layer contains a benzo[e]imidazo[5,1-c][1,2,4]triazine compound with the structural formula shown in formula (1): ； （1）； Wherein, R1 is an electron-withdrawing group of C6 to C30, and is selected from one of phenylcyano and its derivatives, pyridine and its derivatives, pyrimidine and its derivatives, triazine and its derivatives, phenanthroline and its derivatives, imidazole and its derivatives, phosphoroxy and its derivatives, benzo[a]nephrine and its derivatives; L1 is an aryl group of C6 to C30 or a heteroaryl group of C6 to C30.

2. The organic electroluminescent device according to claim 1, characterized in that, The benzo[e]imidazo[5,1-c][1,2,4]triazine compound has the structural formula shown in formula (2): ； （2）； Wherein, when X1 to X4 do not bond with each other to form an aromatic ring or heteroaromatic ring structure, X1 to X4 represent hydrogen atoms or deuterium atoms; when X1 to X4 bond with each other to form an aromatic ring or heteroaromatic ring structure, the aromatic ring or heteroaromatic ring structure contains one or both of carbon atoms and nitrogen atoms.

3. The organic electroluminescent device according to claim 1, characterized in that, There are 1 to 3 L1s, and each L1 is selected from one of the following structural formulas: ； R3 is a C6-C30 aryl group or a C6-C30 heteroaryl group.

4. The organic electroluminescent device according to claim 3, characterized in that, R1 can be independently represented as one of the following structural formulas: ； X, Y, and Z are each independently selected from nitrogen atoms or carbon atoms, and at least one of them contains a nitrogen atom; R4 is selected from aliphatic alkyl chains, alkoxy groups, C6-C30 aryl groups, substituted C6-C30 aryl groups, C2-C30 heteroaryl groups, or substituted C2-C30 heteroaryl groups.

5. The organic electroluminescent device according to claim 1, characterized in that, The benzo[e]imidazo[5,1-c][1,2,4]triazine compound is selected from any of the structures shown in Formulas 5-1 to 5-53: 。 6. The organic electroluminescent device according to claim 1, characterized in that, The electron transport layer also contains an n-doper, and the benzo[e]imidazo[5,1-c][1,2,4]triazine compound forms an n-doping complex with the n-doper.

7. The organic electroluminescent device according to claim 6, characterized in that, The n-doper is selected from at least one of lithium, copper, silver, gold, magnesium, barium, ytterbium, cesium, lithium oxide, copper oxide, silver oxide, gold oxide, magnesium oxide, barium oxide, ytterbium oxide, cesium oxide, lithium carbonate, copper carbonate, silver carbonate, gold carbonate, magnesium carbonate, barium carbonate, ytterbium carbonate, cesium carbonate, lithium 8-hydroxyquinoline, sodium 8-hydroxyquinoline, ZnO, and CsN3.

8. The organic electroluminescent device according to claim 6, characterized in that, The doping concentration of the n-doper is 0.1% to 30% by mass percentage.

9. The organic electroluminescent device according to claim 1, characterized in that, The organic light-emitting functional layer, from the anode layer to the cathode layer, sequentially includes a hole injection layer, a first hole transport layer, a second hole transport layer, a light-emitting layer, a second electron transport layer, a first electron transport layer, and an electron injection layer. The first electron transport layer is the electron transport layer containing the benzo[e]imidazo[5,1-c][1,2,4]triazine compound. The material of the second electron transport layer is an aromatic ring having a nitrogen-containing six-membered ring skeleton or a nitrogen-containing five-membered ring skeleton, or a fused aromatic ring compound having a nitrogen-containing six-membered ring skeleton or a nitrogen-containing five-membered ring skeleton.

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