An organic electroluminescent compound, a preparation method and application thereof, and an organic electroluminescent device comprising the same

Abstract

The present invention belongs to the field of organic optoelectronic materials, and discloses an organic electroluminescent compound, a preparation method and application thereof, and an organic electroluminescent device containing the same. The general structural formula of the organic electroluminescent compound is that the compound uses a heterocyclic structure of a dibenzoazepine structure as a mother nucleus, and by fusing benzofuran / thiophene / fluorene / carbazole groups and connecting with triarylamine groups, the obtained compound can be used in red organic electroluminescent devices, and the prepared devices have characteristics such as high luminous efficiency, low driving voltage and long service life.

Description

Technical Field

[0001] The present invention belongs to the field of organic optoelectronic materials, and particularly relates to an organic electroluminescent compound, a preparation method and application thereof, and an organic electroluminescent device comprising the same. Background Art

[0002] Organic electroluminescence (EL) refers to a luminescence phenomenon in which organic materials directly convert electrical energy into light energy under the action of an electric field. An organic electroluminescent device is a spontaneous light-emitting device using the above principle, which has the characteristics of self-luminescence, bright and vivid colors, thin thickness, light weight, fast response speed, wide viewing angle, low driving voltage, tolerance to harsh natural conditions, and can be made into a flexible panel, and has gradually developed into the most advantageous technology in the new generation of flat panel display fields.

[0003] An organic electroluminescent device generally has the following structure: an anode, a cathode, and an organic material layer therebetween. In order to improve the efficiency and stability of the organic EL element, the organic material layer includes multiple layers with different materials, such as a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting auxiliary layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer (ETL), and an electron injection layer (EIL). Among them, layers with the function of transporting holes, such as the hole injection layer, the hole transport layer, and the electron blocking layer, can change the hole transport efficiency, luminescence efficiency, lifespan, etc. of holes to the light-emitting layer, and have a great impact on the performance data of electronic devices.

[0004] Generally, a light-emitting auxiliary layer is added between the hole transport layer and the light-emitting layer (that is, multiple hole transport layers are provided) to improve the lifespan and efficiency of the device. The light-emitting auxiliary layer can reduce the potential barrier between the hole transport layer and the light-emitting layer, reduce the driving voltage of the organic electroluminescent device, further increase the utilization rate of holes, thereby improving the luminescence efficiency and lifespan of the device and reducing the driving voltage. However, there are few functional materials that can form a light-emitting auxiliary layer at present. In particular, problems such as the unobvious improvement of the lifespan and luminescence efficiency of OLEDs and the relatively low glass transition temperature have led to the development of higher-performance organic functional materials to meet the requirements of panel manufacturing enterprises being particularly important. Summary of the Invention

[0005] In view of this, the present invention provides a light-emitting auxiliary material, which can effectively improve the lifespan and luminescence efficiency of OLED devices and reduce the driving voltage by optimizing its structure.

[0006] In order to achieve the above object, the first object of the present invention is to provide an organic electroluminescent compound. The following technical solution is adopted:

[0007] An organic electroluminescent compound has the following general structural formula:

[0008]

[0009] Among them,

[0010] R1, R2, R3, and R4 are each independently hydrogen, C1-C10 alkyl, cyano, amino, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl, and the substitution positions of R1-R4 can be any position on the benzene ring where they are located, and the number of substitutions is an integer from 0 to 4;

[0011] W and V each independently represent a linking bond, O, S, CR5R6, or NR7;

[0012] R5 and R6 are each independently substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl, and R7 is each independently substituted or unsubstituted C6-C30 aryl or substituted or unsubstituted C3-C30 heteroaryl;

[0013] Ar1-Ar4 and L1-L2 represent substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted 3- to 30-membered heterocycloalkyl, where the heteroatoms are N, O, S, Si, P, or Se; substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted 3- to 30-membered heteroaryl, where the heteroatoms are N, O, S, Si, P, or Se; substituted or unsubstituted C10-C30 fused ring group, substituted or unsubstituted C5-C30 spiro ring group, or one or more of them;

[0014] n and p are each independently 0 or 1, and n and p are not both 0.

[0015] It should be noted that the present invention is based on a heterocyclic compound with a dibenzoazepine structure, and a benzofuran / thiophene / fluorene / carbazole group is attached. The introduced bis-triarylamine structure increases the molecular weight and the symmetry of the molecular spatial structure of the compound, making the compound more stable. Although the efficiency is reduced in terms of device performance, the lifespan is greatly increased. Moreover, considering the device efficiency, the parent nucleus structure modified with a single triarylamine disclosed in the present invention simultaneously improves the device performance of the driving voltage, luminous efficiency, and lifespan. Although the lifespan is not increased as significantly as that of the parent nucleus modified with bis-triarylamine, the driving voltage is significantly reduced, and the efficiency is significantly improved.

[0016] Furthermore, W and V are in the following structures:

[0017]

[0018] Among them, R5 and R6 are each independently methyl, ethyl, phenyl, naphthyl, biphenyl or terphenyl; R7 is independently phenyl, naphthyl, methylbenzene, biphenyl or terphenylphenanthryl, anthryl, pyridyl.

[0019] Furthermore, the general formula I is represented by any one of the following formulas I-1 to I-6:

[0020]

[0021]

[0022] Among them,

[0023] R1, R2, R3, and R4 are each independently hydrogen, methyl, tert-butyl, ethyl, cyano, phenyl, naphthyl, biphenyl, terphenyl, phenanthryl, anthryl, pyrenyl, perylenyl, triphenylene or methoxyalkyl, and R1, R2, R3 or R4 is fused with the adjacent aromatic ring to form a ring or is substituted;

[0024] Ar1-Ar4 and L1-L2 represent a substituted or unsubstituted C6-C24 aryl group, a substituted or unsubstituted 3- to 20-membered heteroaryl group, wherein the heteroatoms are N, O, S, Si, P, Se, etc.; one or more of a substituted or unsubstituted C10-C30 fused ring group, a substituted or unsubstituted C5-C30 spiro ring group;

[0025] n and p are each independently 0 or 1, and n and p are not both 0.

[0026] Furthermore, the general formula I is represented by any one of the following formulas (1) to (16):

[0027]

[0028]

[0029] Furthermore, the general formula I is represented by any one of the following formulas I-1-a to I-2-c:

[0030]

[0031]

[0032] It should be noted that in the above terms of the present invention, "substituted" means that the hydrogen atom bonded to the carbon atom of the compound becomes another substituent, and the position of substitution is not limited as long as the position is the position where the hydrogen atom is substituted (i.e., the position where the substituent can be substituted), and when two or more substituents are substituted, the two or more substituents can be the same or different from each other.

[0033] Furthermore, the compound represented by General Formula I is represented by any one of the following Formulas 1 to 120:

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] The second object of the present invention is to provide an application of the above-mentioned organic electroluminescent compound in the preparation of an organic light-emitting device, an organic solar cell, an electronic paper, an organic photoreceptor or an organic thin-film transistor.

[0042] The third object of the present invention is to provide a preparation method of the above-mentioned organic electroluminescent compound, adopting the following technical solution:

[0043] When only one of n and p is 1 and L1-L2 exists, the following reaction steps are included:

[0044] Under N2 protection, the intermediate D-I (1.0 eq), the reactant E-I-1 (or E-I-2) (1-1.2 eq), tetrakis(triphenylphosphine)palladium (0.01-0.02 eq) and potassium carbonate (2.1-2.3 eq) are respectively added to a mixed solvent of toluene, ethanol and water (2-4:1:1), heated to 100-120 °C, reacted for 8 h. After the reaction is completed, it is cooled to room temperature. After the solid has precipitated completely, it is filtered by suction, washed with water to remove salts, then rinsed with a small amount of ethanol, the filter cake is dried, and recrystallized in 1,4-dioxane to obtain the compound represented by General Formula I; or,

[0045] When only one of n and p is 1 but L1-L2 does not exist, the following reaction steps are included:

[0046] After adding intermediate D-I (1.0 eq) and reactant E-II-1 (or E-II-2) (1.0 - 1.4 eq) dissolved in toluene into the reaction vessel, Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.02 - 0.04 eq), and t-BuONa (1.5 - 3.0 eq) were added under a N2 atmosphere. After the addition, the reaction temperature was slowly raised to 105 - 115 °C, and the mixture was stirred for 8 - 12 h. The mixture was filtered hot through diatomaceous earth to remove salts and the catalyst. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After liquid separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, and then the combined organic layers were dried over magnesium sulfate. The solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography using dichloromethane:petroleum ether volume ratio of 1:(1 - 9) as the eluent to obtain the general formula I; or,

[0047] When n and p are both 1 and L1 - L2 is present, the following reaction steps are included:

[0048] (1) Under N2 protection, intermediate D-I (1.0 eq), reactant e-I-1 (1 - 1.2 eq), tetrakis(triphenylphosphine)palladium (0.01 - 0.02 eq), and potassium carbonate (2.1 - 2.3 eq) were separately added to a mixed solvent of toluene, ethanol, and water (2 - 4:1:1). The temperature was raised to 100 - 120 °C and the reaction was carried out for 8 h. After the reaction was completed, it was cooled to room temperature. After the solid had precipitated completely, it was filtered and washed with water to remove salts, then rinsed with a small amount of ethanol, and the filter cake was dried and recrystallized in 1,4-dioxane to obtain intermediate d-I;

[0049] (2) Under N2 protection, intermediate d-I (1.0 eq), reactant e-I-2 (1 - 1.2 eq), tetrakis(triphenylphosphine)palladium (0.01 - 0.02 eq), and potassium carbonate (2.1 - 2.3 eq) were separately added to a mixed solvent of toluene, ethanol, and water (2 - 4:1:1). The temperature was raised to 100 - 120 °C and the reaction was carried out for 8 h. After the reaction was completed, it was cooled to room temperature. After the solid had precipitated completely, it was filtered and washed with water to remove salts, then rinsed with a small amount of ethanol, and the filter cake was dried and recrystallized in 1,4-dioxane to obtain the compound shown by the general formula I; or,

[0050] When n and p are both 1 but L1 - L2 is absent, the following reaction steps are included:

[0051] (1) After adding intermediate D-I (1.0 eq) and reactant e-II-1 (1.0 - 1.4 eq) dissolved in toluene into the reaction vessel, Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.02 - 0.04 eq), and t-BuONa (1.5 - 3.0 eq) were added under a N2 atmosphere. After the addition, the reaction temperature was slowly raised to 105 - 115 °C, and the mixture was stirred for 8 - 12 h. The mixture was filtered through diatomaceous earth while it was hot to remove salts and catalysts. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After liquid separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, then the combined organic layer was dried using magnesium sulfate, and the solvent was removed using a rotary evaporator. Using dichloromethane:petroleum ether volume ratio of 1:(1 - 9) as the eluent, the remaining material was purified by column chromatography to obtain intermediate d-II;

[0052] (2) After adding intermediate d-II (1.0 eq) and reactant e-II-2 (1.0 - 1.4 eq) dissolved in toluene into the reaction vessel, Pd2(dba)3 (0.01 eq), P(t-Bu)3 (0.02 - 0.04 eq), and t-BuONa (1.5 - 3.0 eq) were added under a N2 atmosphere. After the addition, the reaction temperature was slowly raised to 105 - 115 °C, and the mixture was stirred for 8 - 12 h. The mixture was filtered through diatomaceous earth while it was hot to remove salts and catalysts. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After liquid separation, the organic phase was retained, the aqueous phase was extracted with ethyl acetate, then the combined organic layer was dried using magnesium sulfate, and the solvent was removed using a rotary evaporator. Using dichloromethane:petroleum ether volume ratio of 1:(1 - 9) as the eluent, the remaining material was purified by column chromatography to obtain general formula I; and,

[0053] Intermediate D-1, reactant E-I-1, reactant E-I-2, reactant e-I-1, reactant e-I-2, reactant E-II-1, reactant E-II-2, reactant e-II-1, reactant e-II-2, intermediate d-I, and intermediate d-II have the following structural general formulas:

[0054]

[0055] Among them,

[0056] R1, R2, R3, and R4 are each independently hydrogen, C1 - C10 alkyl, cyano, amino, substituted or unsubstituted C6 - C30 aryl, or substituted or unsubstituted C3 - C30 heteroaryl, and the substitution positions of R1 - R4 can be any position on the benzene ring where they are located, and the number of substitutions is an integer from 0 to 4;

[0057] W and V each independently represent a linking bond, O, S, CR5R6 or NR7;

[0058] R5 and R6 are each independently a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C3-C30 heteroaryl group, and R7 is each independently a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C3-C30 heteroaryl group;

[0059] Ar1 - Ar4 and L1 - L2 represent a substituted or unsubstituted C3 - C20 cycloalkyl group, a substituted or unsubstituted 3 - 30 membered heterocycloalkyl group, wherein the heteroatom is N, O, S, Si, P or Se; a substituted or unsubstituted C6 - C30 aryl group, a substituted or unsubstituted 3 - 30 membered heteroaryl group, wherein the heteroatom is N, O, S, Si, P or Se; a substituted or unsubstituted C10 - C30 fused ring group, a substituted or unsubstituted C5 - C30 spiro ring group, one or more of which.

[0060] Furthermore, the following steps are also included:

[0061] (1) In a reaction flask, under nitrogen protection, add reactant A-I (1.0 eq), reactant B-I (2.2 eq), CuI (0.1 eq), o-phenanthroline (0.1 eq), DMF, cesium carbonate (2.0 eq), react at 150 °C for 12 h. After the reaction is completed, cool to room temperature, filter, and the obtained solid is purified by recrystallization with toluene to obtain intermediate C-I;

[0062] (2) In a reaction flask, under nitrogen protection, add intermediate C-I (1.0 eq), Pd(OAc)2 (0.01 eq), Pcy3 (0.02 eq) and potassium carbonate (3.0 eq) / DMF, react at 150 °C for 12 h. After the reaction is completed, the mixture is washed with distilled water and extracted with ethyl acetate. The obtained organic layer is dried with magnesium sulfate, and the solvent is removed therefrom by a rotary evaporator. Using dichloromethane:petroleum ether volume ratio of 1:(1 - 9) as the eluent, purify with a chromatography column to obtain intermediate D-I; and,

[0063] The reactant A-I, reactant B-I and intermediate C-I have the following general structural formulas:

[0064]

[0065] Wherein,

[0066] W and V each independently represent a linking bond, O, S, CR5R6 or NR7;

[0067] R1, R2, R3, and R4 are each independently hydrogen, a C1-C10 alkyl group, a cyano group, an amino group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C3-C30 heteroaryl group; and, the substitution positions of R1-R4 can be any position on the benzene ring where they are located, and the number of substitutions is an integer from 0 to 4;

[0068] R5 and R6 are each independently a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C3-C30 heteroaryl group;

[0069] n and p are each independently 0 or 1, and n and p are not both 0.

[0070] The fourth object of the present invention is to provide an organic electroluminescent device, including a first electrode, a second electrode, and one or more organic layers disposed between the first electrode and the second electrode; and

[0071] The organic layer includes at least one of a hole injection layer, a hole transport layer, a light-emitting auxiliary layer, a light-emitting layer, an electron transport layer, and an electron injection layer; and,

[0072] The light-emitting auxiliary layer contains one or more of the above-mentioned organic electroluminescent compounds.

[0073] The present invention does not limit the preparation method of the organic electroluminescent device. Preferably, a metal, a conductive oxide, and their alloys are evaporated on a substrate by methods such as thin film evaporation, electron beam evaporation, or physical vapor deposition to form an anode, and then an organic layer and a cathode are formed thereon to obtain an organic electroluminescent device.

[0074] Compared with the prior art, the present invention provides a heterocyclic compound with a dibenzoazepine structure. By fusing benzofuran / thiophene / fluorene / carbazole groups and connecting them with triarylamine groups, the obtained compound can be used in red organic electroluminescent devices. The prepared devices have characteristics such as high luminous efficiency, low driving voltage, and long service life. Among them, the triarylamine structure can reduce the crystallinity of the molecule, reduce the planarity of the molecule, prevent the movement of the molecule on the plane, and at the same time, the high hole transport rate can reduce the driving voltage of the device, improve the efficiency and service life of the organic electroluminescent device. The condensed aromatic ring or condensed heterocyclic ring structure usually has a good conjugated planar structure and thermal stability, which is beneficial to charge transport and molecular stability. More specifically, when such substituents are located at the ortho position of the arylamine, the steric hindrance of the molecule can be increased, preventing the molecule from being overly planar and forming crystals at high temperatures. Due to the structural characteristics of these two aspects, the molecule as a whole exhibits good hole injection and migration properties. Description of the Drawings

[0075] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings described below are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0076] Figure 1 1H NMR spectrum of compound 1 prepared in Example 1 of the present invention.

[0077] Figure 2 1H NMR spectrum of compound 5 prepared in Example 2 of the present invention.

[0078] Figure 3 1H NMR spectrum of compound 78 prepared in Example 3 of the present invention.

[0079] Figure 4 1H NMR spectrum of compound 114 prepared in Example 4 of the present invention. Detailed implementation manners

[0080] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0081] Example 1: Synthesis of compound 1

[0082] (1) In a reaction flask, under nitrogen protection, add reactant A-1 (50 mmol), reactant B-1 (110 mmol), CuI (5 mmol), o-phenanthroline (5 mmol), DMF (500 mL), cesium carbonate (100 mmol), and react at 150 °C for 12 h; after the reaction is completed, cool to room temperature, filter, and the obtained solid is purified by recrystallization with toluene to obtain intermediate C-1 (19.2 g, yield: 70%, Ms: 548.72);

[0083] (2) In a reaction flask, under nitrogen protection, add intermediate C-1 (30 mmol), Pd(OAc)2 (0.3 mmol), Pcy3 (0.6 mmol) and potassium carbonate (90 mmol) / DMF (300 mL), and react at 150 °C for 12 h; after the reaction is completed, the mixture is washed with distilled water and extracted with ethyl acetate. The obtained organic layer is dried with magnesium sulfate, and the solvent is removed therefrom by a rotary evaporator. Using dichloromethane:petroleum ether volume ratio of 1:(1-9) as the eluent, purify by column chromatography to obtain intermediate D-1 (9.6 g, yield: 68%, Ms: 468.31).

[0084] (3) Add intermediate D-1 (18 mmol) and reactant E-1 (21.6 mmol) to toluene in a reaction vessel. After that, add Pd2(dba)3 (0.18 mmol), P(t-Bu)3 (0.36 mmol), and t-BuONa (27 mmol) under a nitrogen atmosphere. After addition, slowly raise the reaction temperature to 110 °C, and stir the mixture for 8 h. Filter while hot using diatomaceous earth to remove salts and catalysts. After the filtrate is cooled to room temperature, then add distilled water to the filtrate for washing. After liquid separation, retain the organic phase, and extract the aqueous phase with ethyl acetate. Then dry the combined organic layer with magnesium sulfate, and remove the solvent using a rotary evaporator. Using dichloromethane:petroleum ether volume ratio of 1:(1-9) as the eluent, purify the remaining material by column chromatography to obtain Compound 1 (11.4 g, yield: 80%).

[0085] HPLC purity: >99.7%.

[0086] Mass spectrometry test: The theoretical value is 793.03; the measured value is Ms: 793.28.

[0087] Elemental analysis:

[0088] Theoretical values: C, 90.87; H, 5.59; N, 3.53

[0089] Measured values: C, 90.73; H, 5.80; N, 3.62.

[0090] 1H NMR is as Figure 1 shown.

[0091]

[0092] Example 2: Synthesis of Compound 5

[0093] (1) In a reaction flask, under nitrogen protection, add reactant A-5 (50 mmol), reactant B-5 (110 mmol), CuI (5 mmol), phenanthroline (5 mmol), DMF (500 mL), and cesium carbonate (100 mmol), and react at 150 °C for 12 h; after the reaction is completed, cool to room temperature, filter, and purify the obtained solid by recrystallization with toluene to obtain intermediate C-5 (17.8 g, yield: 65%, Ms: 548.67);

[0094] (2) In a reaction flask, under nitrogen protection, add intermediate C-5 (30 mmol), Pd(OAc)2 (0.3 mmol), Pcy3 (0.6 mmol), and potassium carbonate (90 mmol) / DMF (300 mL), and react at 150 °C for 10 h; after the reaction is completed, wash the mixture with distilled water and extract with ethyl acetate. Dry the obtained organic layer with magnesium sulfate, and remove the solvent therefrom by a rotary evaporator. Use dichloromethane:petroleum ether volume ratio of 1:(1 - 9) as the eluent, and purify by a chromatography column to obtain intermediate D-5 (10.4 g, yield: 74%, Ms: 468.30);

[0095] (3) Under N2 protection, add intermediate D-5 (18 mmol), reactant E-5 (37.8 mmol), tetrakis(triphenylphosphine)palladium (0.36 mmol), and potassium carbonate (37.8 mmol) to a mixed solvent of toluene, ethanol, and water (300 mL:100 mL:100 mL) respectively, heat to 100 °C, and react for 8 h. After the reaction is completed, cool to room temperature. After the solid has precipitated completely, filter, wash with water to remove salts, then rinse with a small amount of ethanol, and dry the filter cake. Recrystallize in 1,4-dioxane to obtain compound 5 (13.0 g, yield: 83%).

[0096]

[0097] HPLC purity: >99.8%.

[0098] Mass spectrometry test: The theoretical value is 869.12; the measured value is Ms: 869.34.

[0099] Elemental analysis:

[0100] Theoretical values: C, 91.21; H, 5.57; N, 3.22

[0101] Measured values: C, 90.90; H, 5.84; N, 3.38.

[0102] 1H NMR is as Figure 2 shown.

[0103] Example 3: Synthesis of Compound 78

[0104] (1) In a reaction flask, under nitrogen protection, add reactant A-78 (50 mmol), reactant B-78 (110 mmol), CuI (5 mmol), phenanthroline (5 mmol), DMF (500 mL), and cesium carbonate (100 mmol), and react at 150 °C for 12 h; after the reaction is completed, cool to room temperature, filter, and purify the obtained solid by recrystallization with toluene to obtain intermediate C-78 (18.3 g, yield: 68%, Ms: 538.77);

[0105] (2) In a reaction flask, under nitrogen protection, add intermediate C-78 (30 mmol), Pd(OAc)2 (0.3 mmol), Pcy3 (0.6 mmol), and potassium carbonate (90 mmol) / DMF (300 mL), and react at 150 °C for 10 h; after the reaction is completed, wash the mixture with distilled water and extract with ethyl acetate. Dry the obtained organic layer with magnesium sulfate, and remove the solvent therefrom by a rotary evaporator. Use dichloromethane:petroleum ether volume ratio of 1:(1-9) as the eluent, and purify by chromatography column to obtain intermediate D-78 (9.9 g, yield: 72%, Ms: 457.66);

[0106]

[0107] (3) Under N2 protection, add intermediate D-78 (18 mmol), reactant E-78 (37.8 mmol), tetrakis(triphenylphosphine)palladium (0.36 mmol), and potassium carbonate (37.8 mmol) to a mixed solvent of toluene, ethanol, and water (300 mL:100 mL:100 mL) respectively, heat to 100 °C, and react for 12 h. After the reaction is completed, cool to room temperature. After the solid precipitates completely, filter with suction, wash with water to remove salts, then rinse with a small amount of ethanol, and dry the filter cake. Recrystallize in 1,4-dioxane to obtain intermediate F-72 (11.0 g, yield: 82%, Ms: 742.76);

[0108] (4) After adding intermediate D-78 (10 mmol) and reactant E-78 (12 mmol) dissolved in toluene into the reaction vessel, Pd2(dba)3 (0.10 mmol), P(t-Bu)3 (0.2 mmol), and t-BuONa (15 mmol) were added under a nitrogen atmosphere. After the addition, the reaction temperature was slowly raised to 110 °C, and the mixture was stirred for 8 h. The mixture was filtered while hot through diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After liquid separation, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate. Then, the combined organic layers were dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography using dichloromethane:petroleum ether volume ratio of 1:(1 - 9) as the eluent to obtain compound 78 (8.0 g, yield: 88%).

[0109] HPLC purity: >99.6%.

[0110] Mass spectrometry test: The theoretical value is 910.15; the measured value is Ms: 910.50.

[0111] Elemental analysis:

[0112] Theoretical values: C, 87.10; H, 4.76; N, 4.62; S, 3.52

[0113] Measured values: C, 86.93; H, 4.94; N, 4.71; S, 3.60.

[0114] 1H NMR is as Figure 3 shown.

[0115] Example 4: Synthesis of compound 114

[0116] (1) In a reaction flask, under nitrogen protection, reactant A-114 (50 mmol), reactant B-115 (110 mmol), CuI (5 mmol), 1,10-phenanthroline (5 mmol), DMF (500 mL), and cesium carbonate (100 mmol) were added, and the reaction was carried out at 150 °C for 12 h; after the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was purified by recrystallization from toluene to obtain intermediate C-114 (21.2 g, yield: 71%, Ms: 597.79);

[0117] (2) In a reaction flask, under nitrogen protection, add intermediate C-114 (30 mmol), Pd(OAc)2 (0.3 mmol), Pcy3 (0.6 mmol) and potassium carbonate (90 mmol) / DMF (300 mL), and react at 150 °C for 10 h; after the reaction is completed, the mixture is washed with distilled water and extracted with ethyl acetate. The obtained organic layer is dried with magnesium sulfate, and the solvent is removed therefrom by a rotary evaporator. Using dichloromethane:petroleum ether volume ratio of 1:(1-9) as the eluent, purify by a chromatography column to obtain intermediate D-114 (10.1 g, 65%, Ms: 517.25);

[0118] (3) Under N2 protection, add intermediate D-114 (18 mmol), reactant E-114 (37.8 mmol), tetrakis(triphenylphosphine)palladium (0.36 mmol) and potassium carbonate (37.8 mmol) to a mixed solvent of toluene, ethanol, water (300 mL:100 mL:100 mL) respectively, heat to 100 °C, react for 10 h. After the reaction is completed, cool to room temperature. After the solid precipitates completely, filter by suction, wash with water to remove salts, and then rinse with a small amount of ethanol, and dry the filter cake. Recrystallize in 1,4-dioxane to obtain compound 114 (14.0 g, 85%).

[0119]

[0120] HPLC purity: >99.8%.

[0121] Mass spectrometry test: The theoretical value is 918.16; the measured value is Ms: 918.29.

[0122] Elemental analysis:

[0123] Theoretical values: C, 90.26; H, 5.16; N, 4.58

[0124] Measured values: C, 90.22; H, 5.34; N, 4.62.

[0125] 1H NMR is as Figure 4 shown.

[0126] Examples 5 - 22

[0127] Refer to the synthesis methods of Examples 1 to 4 to complete the synthesis of compounds 12, 17, 21, 24, 29, 36, 45, 54, 60, 66, 74, 80, 82, 90, 97, 103, 112, 120. The mass spectrometry characterization data, molecular formulas and yields are shown in Table 1 below.

[0128] Table 1 Structural characterization data and yields of products in Examples 5 - 22

[0129]

[0130]

[0131] In addition, it should be noted that other compounds of the present application can be obtained by referring to the synthesis methods of the above-listed embodiments, so they will not be elaborated herein.

[0132] Furthermore, the present invention also provides an organic electroluminescent device, which includes a first electrode, a second electrode disposed opposite to the first electrode, and one or more organic layers provided between the first electrode and the second electrode. At least one of the organic layers contains the compound represented by Formula I prepared according to the present invention.

[0133] The organic light-emitting element of the present invention may have a structure including a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting auxiliary layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc. as organic layers. However, the structure of the organic light-emitting element is not limited thereto, and it may include a smaller or larger number of organic layers.

[0134] According to an embodiment of the present specification, the organic layer includes a light-emitting auxiliary layer, and the light-emitting auxiliary layer contains the compound represented by Formula I prepared according to the present invention.

[0135] When the above organic light-emitting element includes a plurality of organic layers, the organic layers may be formed of the same substance or different substances.

[0136] Regarding the compound represented by the above Chemical Formula I, when manufacturing an organic light-emitting element, an organic layer can be formed by using a vacuum evaporation method or a solution coating method. Among them, the so-called solution coating method refers to a spin coating method, a dip coating method, a blade coating method, an inkjet printing method, a screen printing method, a spraying method, a roll coating method, etc., but is not limited thereto.

[0137] The organic light-emitting element of the present invention can be a top-emitting type, a bottom-emitting type, or a double-sided emitting type according to the materials used.

[0138] The device described in the present invention can be used in an organic light-emitting device, an organic solar cell, an electronic paper, an organic photoreceptor, or an organic thin-film transistor.

[0139] Preparation of a Red Organic Electroluminescent Device in Example 23

[0140] a, ITO Anode: Clean a glass substrate of ITO (Indium Tin Oxide)-Ag-ITO (Indium Tin Oxide) with a coating thickness of 150 nm twice in distilled water, wash it ultrasonically for 30 min, then wash it repeatedly twice with distilled water and ultrasonically for 10 min. After the washing is completed, transfer it to a spin dryer for spin drying, and finally bake it in a vacuum oven at 220 °C for 2 hours. After the baking is completed and the temperature drops, it can be used. Using this substrate as the anode, use an evaporation coater to perform the evaporation coating device process, and sequentially evaporate other functional layers on it.

[0141] b, HIL (Hole Injection Layer): At an evaporation rate of / s, vacuum evaporate the hole injection layer materials HT and P-dopant, and their chemical formulas are as shown below. The evaporation rate ratio of HT and P-dopant is 97:3, and the thickness is 10 nm;

[0142] c, HTL (Hole Transport Layer): At an evaporation rate of / s, vacuum evaporate 125 nm of HT on the hole injection layer as the hole transport layer;

[0143] d, Light Emission Auxiliary Layer: At an evaporation rate of / s, vacuum evaporate 100 nm of Compound 1 provided in the above embodiment on the hole transport layer as the light emission auxiliary layer;

[0144] e, EML (Emission Layer): Then, on the above light emission auxiliary layer, at an evaporation rate of / s, vacuum evaporate a main material (Host) and a doping material (Dopant) with a thickness of 40 nm as the emission layer, and their chemical formulas of Host and Dopant are as shown below. The evaporation rate ratio of Host and Dopant is 97:3.

[0145] f, HB (Hole Blocking Layer): At an evaporation rate of / s, vacuum evaporate a hole blocking layer with a thickness of 5.0 nm.

[0146] g, ETL (Electron Transport Layer): At an evaporation rate of / s, vacuum evaporate a thickness of 30 nm of ET and Liq as the electron transport layer, and the chemical formula of ET is as shown below. The evaporation rate ratio of ET and Liq is 50:50.

[0147] h, EIL (Electron Injection Layer): At an evaporation rate of / s, evaporate a Yb film layer of 1.0 nm to form an electron injection layer.

[0148] i, Cathode: At an evaporation rate of The evaporation rate ratio is / s. Magnesium and silver are evaporated at 18 nm, and the evaporation rate ratio is 1:9 to form a cathode.

[0149] j. Light extraction layer: At / s evaporation rate, CPL with a thickness of 70 nm is vacuum-evaporated on the cathode as the light extraction layer.

[0150] k. Package the evaporated substrate. First, use a gluing device to coat the cleaned cover plate with UV glue, then move the coated cover plate to the lamination section, place the evaporated substrate on top of the cover plate, and finally laminate the substrate and the cover plate under the action of a laminating device, while completing the light curing of the UV glue.

[0151] Red light device structure:

[0152] ITO / Ag / ITO / HT:P-dopant(10nm) / HT(125nm) / Compound 1(100nm) / Host-R:Dopant-R(40nm) / HB(5nm) / ET:Liq(30nm) / Yb(1nm) / Mg:Ag(18nm) / CPL(70nm).

[0153]

[0154] Example 24 - 97

[0155] Prepare the organic electroluminescent devices of Examples 24 - 97 according to the above preparation method of organic electroluminescent devices, except that Compound 1 in Example 23 is replaced with the corresponding compounds in Table 3 to form a light-emitting auxiliary layer.

[0156] Comparative Example 1

[0157] Prepare an organic electroluminescent device according to the above preparation method of organic electroluminescent devices, except that Compound 1 in Example 23 is replaced with Comparative Compound 1, and the structure of Comparative Compound 1 is shown in Table 2.

[0158] Comparative Example 2

[0159] Prepare an organic electroluminescent device according to the above preparation method of organic electroluminescent devices, except that Compound 1 in Example 23 is replaced with Comparative Compound 2, and the structure of Comparative Compound 2 is shown in Table 2.

[0160] Comparative Example 3

[0161] Prepare an organic electroluminescent device according to the above preparation method of organic electroluminescent devices, except that Compound 1 in Example 23 is replaced with Comparative Compound 3, and the structure of Comparative Compound 3 is shown in Table 2.

[0162] Comparative Example 4

[0163] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that Compound 1 in Example 23 was replaced with Comparative Compound 4, and the structure of Comparative Compound 4 is shown in Table 2.

[0164] Comparative Example 5

[0165] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that Compound 1 in Example 23 was replaced with Comparative Compound 5, and the structure of Comparative Compound 5 is shown in Table 2.

[0166] Comparative Example 6

[0167] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that Compound 1 in Example 23 was replaced with Comparative Compound 6, and the structure of Comparative Compound 6 is shown in Table 2.

[0168] Table 2 Structural formulas of Comparative Compounds 1 - 6

[0169]

[0170] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Examples 23 - 97 and Comparative Examples 1 - 6 were characterized at a brightness of 6000 (nits), and the test results are shown in Table 3 below:

[0171] Table 3 Luminescence characteristics of organic electroluminescent devices (brightness value is 6000 nits)

[0172]

[0173]

[0174]

[0175]

[0176] As can be seen from Table 3, compared with the existing organic electroluminescent devices provided in Comparative Examples 1 - 6, the organic electroluminescent devices prepared using the luminescence assisting material provided by the present invention in Examples 23 - 97 have improved driving voltage, luminous efficiency, and lifetime.

[0177] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent compound, characterized in that, It has the following structural general formula: The specific structure is as follows:

2. Use of an organic electroluminescent compound as described in claim 1, characterized in that, The application of the organic electroluminescent compound in preparing an organic light-emitting device, an organic solar cell, an electronic paper, an organic photoreceptor or an organic thin-film transistor.

3. An organic electroluminescent device, characterized in that, It includes a first electrode, a second electrode, and one or more organic layers disposed between the first electrode and the second electrode; and, The organic layer at least includes one of a hole injection layer, a hole transport layer, a light-emitting auxiliary layer, a light-emitting layer, an electron transport layer, and an electron injection layer; and, The light-emitting auxiliary layer contains one or more organic electroluminescent compounds as described in claim 1.

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