A blue light-emitting compound containing a cyclohexyldibenzofuran structure and an organic electroluminescent device containing the same

Abstract

The present invention discloses a blue light-emitting compound containing a cyclohexyldibenzofuran structure and an organic electroluminescent device containing the same. The general structural formula of the blue light-emitting compound is as shown in Formula I or Formula II, wherein Ar1 represents a cyclohexyldibenzofuran group. By introducing a cyclohexyldibenzofuran group into the compound structure, the intermolecular distance is increased under the mutual repulsion of the lone pair electrons of the oxygen atom, the fluorescence quantum yield is improved, and it is beneficial to improve the efficiency of the device and extend the life. In addition, the compound of the present invention has good thermal stability and its rigidity is also enhanced, thereby indirectly reducing the problem of device performance degradation due to heat generation, which is beneficial to further improve the efficiency and life of the device. I; II.

Description

Technical Field

[0001] The present invention belongs to the technical field of OLEDs, and specifically comprises a blue light-emitting compound containing a cyclohexyldibenzofuran structure and an organic electroluminescent device containing the same. Background Art

[0002] Ever since Academician Tang Benzhong and his research team first discovered aggregation-induced emission in 2001, people have been deeply interested in this unique phenomenon. Compared with traditional display technologies, OLEDs offer advantages such as self-luminescence, wide viewing angles, high brightness, high contrast, low power consumption, low drive voltage, flexible display, and fast response speed. With the advancement of the times and the continuous innovation of internet technology, the OLED industry, as an indispensable gateway to intelligence, is poised for broad growth.

[0003] OLED devices can be categorized by their luminescence mechanism as fluorescence, phosphorescence, thermally excited delayed fluorescence, and thermally excited sensitized fluorescence. Currently, research on OLED active layers primarily focuses on fluorescent materials, whose internal quantum efficiency (the ratio of the number of photons radiated to the number of injected carriers) reaches a maximum of 25%. This is because the ratio of singlet to triplet states generated under electrical excitation is 1:3, resulting in only 25% of singlet excitons undergoing radiative transitions, while triplet excitons undergo non-radiative decay due to spin prohibition. Among OLED fluorescent materials, blue-emitting materials offer advantages such as low driving voltage, slow decay, high repeatability, and adjustable color purity. Consequently, the development of high-efficiency, long-life, and thermally stable blue-emitting OLED materials and related device research has become a major challenge in the OLED research field.

[0004] The thermal stability of OLEDs is a key factor affecting their service life and performance, especially in high-temperature environments, where efficiency degradation, metal migration, and material aging are prone to occur. Previous studies have shown that the introduction of dibenzofuran substituents into the guest material can increase the electron cloud density of the compound. The rigid dibenzofuran structure helps enhance the structural stability of the compound and improve device efficiency. As research continues to deepen, attempts have been made to introduce other substituents alongside dibenzofuran to further improve the efficiency and lifespan of OLED devices. For example, the introduction of tetramethylcyclohexyl groups increases the electron cloud density of the dibenzofuran core. However, the excessive number of methyl groups results in tight molecular stacking, which is not conducive to the thermal stability of the guest material. Ultimately, the improvements in device efficiency and lifespan have not achieved the expected results. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the present invention provides a blue light-emitting compound containing a cyclohexyldibenzofuran structure and an organic electroluminescent device containing the same.

[0006] To achieve the above objectives, the technical solutions adopted by the present invention include:

[0007] The first aspect of the present invention provides a blue light-emitting compound containing a cyclohexyldibenzofuran structure, wherein the general structural formula of the blue light-emitting compound is as shown in Formula I or Formula II:

[0008] I; II;

[0009] in,

[0010] X represents O or S;

[0011] Ar1 represents a cyclohexyldibenzofuranyl group;

[0012] Ar2 represents any one of a substituted or unsubstituted aryl group having C6 to C60 carbon atoms, a substituted or unsubstituted heteroaryl group having C5 to C60 carbon atoms, a substituted or unsubstituted condensed ring aryl group having C6 to C60 carbon atoms, and a substituted or unsubstituted heterocondensed ring aryl group having C5 to C60 carbon atoms;

[0013] L represents a single bond, or a substituted or unsubstituted arylene group having carbon atoms of C6 to C12;

[0014] R1, R2, and R3 each independently represent any one of hydrogen, deuterium, halogen, a substituted or unsubstituted alkyl group having C1 to C30 carbon atoms, a substituted or unsubstituted alkenyl group having C2 to C30 carbon atoms, a substituted or unsubstituted cycloalkyl group having C3 to C30 carbon atoms, a substituted or unsubstituted aryl group having C6 to C60 carbon atoms, a substituted or unsubstituted heteroaryl group having C5 to C60 carbon atoms, a substituted or unsubstituted fused ring aryl group having C6 to C60 carbon atoms, and a substituted or unsubstituted heterofused ring aryl group having C5 to C60 carbon atoms, wherein two or more R1, R2, and R3 may be linked to form an aliphatic ring, an aromatic ring, or a fused ring;

[0015] When Ar2, R1, R2, and R3 contain substituents, the substituents are selected from any one of an alkyl group having C1 to C10 carbon atoms, a cycloalkyl group having C3 to C10 carbon atoms, an aryl group having C6 to C20 carbon atoms, and a substituted or unsubstituted heteroaryl group having C5 to C20 carbon atoms;

[0016] m and p each independently represent 0, 1, 2, 3 or 4, and n represents 0, 1, 2 or 3;

[0017] In Formula I and Formula II, any hydrogen may be replaced by deuterium, any nitrogen may be replaced by nitrogen-15, any sulfur may be replaced by sulfur-33, sulfur-34 or sulfur-36, any oxygen may be replaced by oxygen-17 or oxygen-18, any carbon may be replaced by carbon-13, and any boron may be replaced by boron-11.

[0018] Further, the X represents O;

[0019] The above-mentioned L represents any one of a single bond, a substituted or unsubstituted phenylene group, and a substituted or unsubstituted naphthylene group.

[0020] Furthermore, Ar1 represents one of the following structures:

[0021] 、 、 .

[0022] Furthermore, the general structural formula of the blue light-emitting compound is shown in one of Formulas I-1 to I-5:

[0023] I-1, I-2, I-3, I-4, I-5.

[0024] Furthermore, R1, R2, and R3 each independently represent any one of hydrogen, deuterium, halogen, a substituted or unsubstituted alkyl group having C1 to C10 carbon atoms, a substituted or unsubstituted cycloalkyl group having C3 to C10 carbon atoms, a substituted or unsubstituted aryl group having C6 to C20 carbon atoms, a substituted or unsubstituted heteroaryl group having C5 to C20 carbon atoms, a substituted or unsubstituted fused ring aryl group having C6 to C20 carbon atoms, and a substituted or unsubstituted hetero-fused ring aryl group having C5 to C20 carbon atoms, wherein two or more R1, R2, and R3 may be connected to form a five-membered ring or a six-membered ring;

[0025] Ar2 represents any one of a substituted or unsubstituted aryl group having C6 to C20 carbon atoms, a substituted or unsubstituted heteroaryl group having C5 to C20 carbon atoms, a substituted or unsubstituted condensed ring aryl group having C6 to C20 carbon atoms, and a substituted or unsubstituted heterocondensed ring aryl group having C5 to C20 carbon atoms.

[0026] Furthermore, the R1 and R2 each independently represent 、 、 、 、 、 Any one of .

[0027] Further, the L represents 、 、 、 Any one of .

[0028] Further, Ar2 represents one of the following structures:

[0029] 、 ;

[0030] R4 represents any one of an alkyl group having carbon atoms of C1 to C10 or a cycloalkyl group having carbon atoms of C3 to C10;

[0031] R5 represents a single substituent to the maximum permissible substituent, and is selected from any one of H, an alkyl group having C1 to C10 carbon atoms, and a cycloalkyl group having C3 to C10 carbon atoms.

[0032] In the present invention, as an example, the alkyl group can be arbitrarily selected from one of methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, etc.;

[0033] As an example, the alkenyl group can be arbitrarily selected from one of vinyl, propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, 1-methylvinyl, etc.;

[0034] As an example, the cycloalkyl group can be arbitrarily selected from cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4,4-dimethylcyclohexyl, 1-adamantyl, 2-adamantyl, 1-norbornyl, 2-norbornyl, etc.;

[0035] As an example, the aryl group can be arbitrarily selected from one of phenyl, biphenyl, terphenyl, o-tolyl, m-tolyl, p-tolyl, etc.;

[0036] As an example, the heteroaryl group can be arbitrarily selected from dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indole, carbazole, pyridine, indole, pyrrolopyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isox ... Quinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, selenobenzodipyridine, preferably one of dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, triazine, benzimidazole, 1,2-azaborine, 1,3-azaborine, 1,4-azaborine, borazole and aza analogs thereof;

[0037] As an example, the fused ring aromatic group can be arbitrarily selected from one of naphthyl, anthracenyl, phenanthrenyl, pyrenyl, etc.;

[0038] As an example, the heteroaryl group can be arbitrarily selected from nitrogen-containing heteroaryl groups such as indolyl, quinolyl, and purinyl, oxygen-containing heteroaryl groups such as benzofuranyl, and sulfur-containing heteroaryl groups such as benzothienyl and thienopyridinyl.

[0039] Furthermore, the blue light-emitting compound is selected from one of the following structures:

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] 。

[0072] A second object of the present invention is to provide an organic electroluminescent device, which includes an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode arranged in sequence on a substrate; wherein the light-emitting layer includes a host material and a guest material, and the guest material includes one or more blue light-emitting compounds as described above.

[0073] Beneficial effects of the present invention:

[0074] The blue light-emitting compound provided by the present invention introduces a cyclohexyl dibenzofuran structure. Under the mutual repulsion of the lone pair electrons of the oxygen atoms in the cyclohexyl dibenzofuran structure, the intermolecular distance is increased, thereby improving the fluorescence quantum yield. At the same time, since cyclohexane dibenzofuran has a non-planar structure, the thermal stability and rigidity of the molecule are increased, indirectly reducing the problem of device performance degradation due to heat. Therefore, using the blue light-emitting compound of the present invention as a guest material for the light-emitting layer to prepare an organic electroluminescent device is conducive to obtaining better luminescence performance, a higher BI value and a longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 Schematic diagram of the structure of the organic electroluminescent device of the present invention.

[0076] Figure 2 This is the PL spectrum of Synthesis Example 1.

[0077] Figure 3 This is the PL spectrum of Synthesis Example 5.

[0078] Description of the drawings: 1-substrate, 2-anode, 3-hole injection layer, 4-hole transport layer, 5-electron blocking layer, 6-light-emitting layer, 7-hole blocking layer, 8-electron transport layer, 9-electron injection layer, 10-cathode, 11-covering layer. DETAILED DESCRIPTION

[0079] In order to more clearly understand the content of the present invention, it will be described in detail with reference to the accompanying drawings and embodiments.

[0080] The organic compound of the present invention is suitable for use in light-emitting elements, display panels, and electronic devices, and is particularly suitable for use in organic electroluminescent devices. The electronic device of the present invention is a device comprising a layer of at least one organic compound, which may also comprise an inorganic material or a layer formed entirely of an inorganic material. The electronic device is preferably an organic electroluminescent device (OLED). The schematic structural diagram of an exemplary organic electroluminescent device is shown in FIG. Figure 1 shown.

[0081] Experimental part

[0082] In order to understand the content of the present invention more clearly, the luminescent characteristics of the organic compound, the preparation method of the organic compound and the device will be explained in detail in conjunction with the examples. Various chemical reactions can be applied to the synthetic method of the compound of one embodiment of the present invention. However, it should be noted that the synthetic method of the compound of one embodiment of the present invention is not limited to the synthetic method described below. Unless otherwise stated, subsequent synthesis is carried out in an anhydrous solvent under a protective gas atmosphere. Solvents and reagents can be purchased from conventional reagent suppliers.

[0083] Synthesis of compounds

[0084] Intermediate synthesis 1

[0085] This example provides an intermediate compound P-10, the synthesis route of which is as follows:

[0086]

[0087] Compound C-1 (50.0 g, 220 mmol), D-1 (38.4 g, 220 mmol), tetrakis(triphenylphosphine)palladium (2.54 g, 2.20 mmol), potassium carbonate (60.72 g, 440 mmol), 1,4-dioxane (400 mL) and deionized water (100 mL) were added to a round-bottom flask purged with nitrogen. The temperature was raised to 90°C with stirring and maintained for 4 h. The reaction mixture was then cooled to room temperature, deionized water (100 mL) and ethyl acetate (500 ml) were added and stirred for 20 min. The organic phase was separated and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure to obtain a crude product. The crude product was purified by silica gel column chromatography (dichloromethane / n-heptane as the mobile phase) to obtain intermediate E-1: 43.16 g, yield: 80%, MS (m / z) (M+): 277.

[0088] To a dry and nitrogen-purged round-bottom flask, intermediate E-1 (40 g, 145 mmol), potassium carbonate (60 g, 435 mmol) and N-methylpyrrolidone (300 mL) were added. The mixture was stirred at 160°C for 2 h under nitrogen protection. The solvent was removed under reduced pressure to obtain a crude product. The crude product was washed with deionized water and ethanol, dried, and purified by silica gel column chromatography (dichloromethane / n-heptane as the mobile phase) to obtain intermediate F-1: 29.8 g, yield: 75%, MS (m / z) (M+): 257.

[0089] To a nitrogen-purged round-bottom flask, intermediate F-1 (29.8 g, 116 mmol), trimethyl borate (12 g, 116 mmol), and tetrahydrofuran (300 mL) were added. Under nitrogen protection, tert-butyl lithium (92.8 mL, 232 mmol) was added dropwise at -50°C within 2 h. The mixture was kept warm for 3 h, and then 40 mL of 5% hydrochloric acid solution was added. Stirring was continued for 2 h. The tetrahydrofuran was evaporated under reduced pressure, and the temperature was lowered to 10°C to produce a solid precipitate. The solid precipitate was filtered and dried to obtain intermediate G-1: 27.3 g, yield: 88%, MS (m / z) (M+): 267.

[0090] To a nitrogen-purged round-bottom flask, intermediate G-1 (27.3 g, 102 mmol), hydroxylaminesulfonic acid (31.74 g, 306 mmol), and sodium hydroxide (6.12 g, 153 mmol) were added, and 300 mL of a mixed solvent of acetonitrile and water (the volume of acetonitrile is 200 mL, and the volume of water is 100 mL) was added. The mixture was stirred and dissolved at room temperature. The reaction was terminated by stirring at room temperature for 4 h. The filtrate was extracted twice with ethyl acetate (200 mL), then dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. After drying, the product was purified by silica gel column chromatography (dichloromethane / n-heptane as the mobile phase) to obtain intermediate P-10: 14.8 g, yield: 61%, MS (m / z) (M+): 238.

[0091] Intermediate Synthesis 2

[0092] This example provides an intermediate compound P-11, the synthesis route of which is as follows:

[0093]

[0094] Referring to the synthesis method of E-1, the raw material D-1 was replaced with D-11 (38.4 g, 220 mmol) to obtain intermediate E-11: 41.94 g, yield: 69%, MS (m / z) (M+): 277.

[0095] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-11 (40 g, 145 mmol) to obtain intermediate F-11: 26.2 g, yield: 70.3%, MS (m / z) (M+): 257.

[0096] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-11 (25 g, 97.3 mmol) to obtain intermediate G-11: 24 g, yield: 93%, MS (m / z) (M+): 267.

[0097] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-11 (24 g, 90.2 mmol) to obtain intermediate P-11: 14.9 g, yield: 70%, MS (m / z) (M+): 238.

[0098] Intermediate synthesis 3

[0099] This example provides an intermediate compound P-12, the synthesis route of which is as follows:

[0100]

[0101] Referring to the synthesis method of E-1, the raw material D-1 was replaced with D-12 (38.4 g, 220 mmol) to obtain intermediate E-12: 43.7 g, yield: 72%, MS (m / z) (M+): 277.

[0102] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-12 (40 g, 145 mmol) to obtain intermediate F-12: 28 g, yield: 25 g, yield: 67.1%, MS (m / z) (M+): 257.

[0103] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-12 (25 g, 97.3 mmol) to obtain intermediate G-12: 22.6 g, yield: 87%, MS (m / z) (M+): 267.

[0104] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-12 (20 g, 75.18 mmol) to obtain the intermediate P-12: 12.83 g, yield: 72%, MS (m / z) (M+): 238.

[0105] Intermediate synthesis 4

[0106] This example provides an intermediate compound P-13, the synthesis route of which is as follows:

[0107]

[0108] Referring to the synthesis method of E-1, the raw material D-1 was replaced with D-13 (38.4 g, 220 mmol) to obtain intermediate E-13: 30 g, yield: 49.35%, MS (m / z) (M+): 277.

[0109] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-13 (30 g, 108.7 mmol) to obtain intermediate F-13: 20 g, yield: 71.6%, MS (m / z) (M+): 257.

[0110] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-13 (20 g, 77.8 mmol) to obtain intermediate G-13: 17.5 g, yield 84.2%, MS (m / z) (M+): 267.

[0111] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-13 (17.5 g, 65.78 mmol) to obtain intermediate P-13: 12.3 g, yield: 79%, MS (m / z) (M+): 238.

[0112] Intermediate synthesis 5

[0113] This example provides an intermediate compound P-14, the synthesis route of which is as follows:

[0114]

[0115] Referring to the synthesis method of E-1, the raw material C-1 was replaced with C-14 (40.0 g, 176 mmol) to obtain intermediate E-14: 27.6 g, yield: 56.8%, MS (m / z) (M+): 277.

[0116] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-14 (25 g, 90.57 mmol) to obtain intermediate F-14: 19.9 g, yield: 85.4%, MS (m / z) (M+): 257.

[0117] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-14 (17 g, 66.1 mmol) to obtain intermediate G-14: 16.2 g, yield: 92%, MS (m / z) (M+): 267.

[0118] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-14 (15 g, 56.39 mmol) to obtain intermediate P-14: 8.9 g, yield: 67%, MS (m / z) (M+): 238.

[0119] Intermediate synthesis 6

[0120] This example provides an intermediate compound P-15, the synthesis route of which is as follows:

[0121]

[0122] Referring to the synthesis method of E-1, the raw material C-1 was replaced with C-14 (50.0 g, 220 mmol), and D-1 was replaced with D-11 (38.4 g, 220 mmol) to obtain intermediate E-15: 39.5 g, yield: 65%, MS (m / z) (M+): 277.

[0123] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-15 (39.5 g, 143 mmol) to obtain intermediate F-15: 29.7 g, yield: 81%, MS (m / z) (M+): 257.

[0124] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-15 (29.7 g, 115.6 mmol) to obtain intermediate G-15: 27.3 g, yield: 88.5%, MS (m / z) (M+): 267.

[0125] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-15 (27.3 g, 102.6 mmol) to obtain intermediate P-15: 17.2 g, yield: 71%, MS (m / z) (M+): 238.

[0126] Intermediate synthesis 7

[0127] This example provides an intermediate compound P-16, the synthesis route of which is as follows:

[0128]

[0129] Referring to the synthesis method of E-1, the raw material C-1 was replaced with C-14 (50.0 g, 220 mmol), and D-1 was replaced with D-12 (38.4 g, 220 mmol) to obtain intermediate E-16: 40.0 g, yield: 66%, MS (m / z) (M+): 277.

[0130] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-16 (35 g, 126.8 mmol) to obtain intermediate F-16: 26.8 g, yield: 82.2%, MS (m / z) (M+): 257.

[0131] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-16 (26.8 g, 104.3 mmol) to obtain intermediate G-16: 22.8 g, yield: 81.9%, MS (m / z) (M+): 267.

[0132] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-16 (22.8 g, 85.7 mmol) to obtain the intermediate P-16: 14.6 g, yield: 72%, MS (m / z) (M+): 238.

[0133] Intermediate synthesis 8

[0134] This example provides an intermediate compound P-17, the synthesis route of which is as follows:

[0135]

[0136] Referring to the synthesis method of E-1, the raw material C-1 was replaced with C-17 (50.0 g, 220 mmol) to obtain intermediate E-17: 44 g, yield: 72%, MS (m / z) (M+): 277.

[0137] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-17 (40 g, 145 mmol) to obtain intermediate F-17: 30.5 g, yield: 82%, MS (m / z) (M+): 257.

[0138] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-17 (30 g, 116.7 mmol) to obtain intermediate G-17: 25.5 g, yield: 81.8%, MS (m / z) (M+): 267.

[0139] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-17 (25 g, 94 mmol) to obtain intermediate P-17: 17.1 g, yield: 77%, MS (m / z) (M+): 238.

[0140] Intermediate Synthesis 9

[0141] This example provides an intermediate compound P-18, the synthesis route of which is as follows:

[0142]

[0143] Referring to the synthesis method of E-1, the raw material C-1 was replaced with C-17 (50.0 g, 220 mmol), and D-1 was replaced with D-11 (38.4 g, 220 mmol) to obtain intermediate E-18: 46 g, yield: 76%, MS (m / z) (M+): 277.

[0144] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-18 (40 g, 145 mmol) to obtain intermediate F-18: 32.8 g, yield: 88%, MS (m / z) (M+): 257.

[0145] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-18 (30 g, 116.7 mmol) to obtain intermediate G-18: 24.6 g, yield: 79%, MS (m / z) (M+): 267.

[0146] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-18 (20 g, 75.18 mmol) to obtain intermediate P-18: 15 g, yield: 84%, MS (m / z) (M+): 238.

[0147] Intermediate Synthesis 10

[0148] This example provides an intermediate compound P-19, the synthesis route of which is as follows:

[0149]

[0150] Referring to the synthesis method of E-1, the raw material C-1 was replaced with C-17 (50.0 g, 220 mmol), and D-1 was replaced with D-12 (38.4 g, 220 mmol) to obtain intermediate E-19: 47.4 g, yield: 78%, MS (m / z) (M+): 277.

[0151] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-19 (40 g, 145 mmol) to obtain intermediate F-19: 32.6 g, yield: 87.5%, MS (m / z) (M+): 257.

[0152] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-19 (30 g, 116.7 mmol) to obtain intermediate G-19: 23 g, yield: 73.8%, MS (m / z) (M+): 267.

[0153] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-19 (20 g, 75.18 mmol) to obtain intermediate P-19: 16 g, yield: 89.8%, MS (m / z) (M+): 238.

[0154] Intermediate Synthesis 11

[0155] This example provides an intermediate compound P-20, the synthesis route of which is as follows:

[0156]

[0157] Referring to the synthesis method of E-1, the raw material C-1 was replaced with C-17 (50.0 g, 220 mmol), and D-1 was replaced with D-13 (38.4 g, 220 mmol) to obtain intermediate E-20: 45 g, yield: 74%, MS (m / z) (M+): 277.

[0158] Referring to the synthesis method of F-1, the raw material E-1 was replaced with E-20 (40 g, 145 mmol) to obtain intermediate F-20: 33.5 g, yield: 90%, MS (m / z) (M+): 257.

[0159] Referring to the synthesis method of G-1, the raw material F-1 was replaced with F-20 (30 g, 116.7 mmol) to obtain intermediate G-20: 24.5 g, yield: 79%, MS (m / z) (M+): 267.

[0160] Referring to the synthesis method of P-10, the raw material G-1 was replaced with G-20 (20 g, 75.18 mmol) to obtain intermediate P-20: 13 g, yield: 73%, MS (m / z) (M+): 238.

[0161] Intermediate synthesis 12

[0162] The synthetic route of intermediate A1 is as follows:

[0163]

[0164] Compound F-18 (25.6 g, 100 mmol), Q-1 (13.7 g, 100 mmol) and potassium carbonate (41.4 g, 300 mmol) were added to a mixed solution of 1,4-dioxane (400 mL) and water (100 mL), and then Pd-132 (0.07 g, 0.1 mmol) was added under nitrogen protection. The reaction system was then heated to 100 ° C. The heating reaction was maintained for 3 h. After cooling to room temperature, deionized water was added to quench the mixture, the liquids were separated, and the organic phase was dried over anhydrous sodium sulfate. The solvent was removed by vortexing, and the crude product was purified by column chromatography to obtain product U-1: 25.6 g, yield: 82%, MS (m / z) (M+): 313.

[0165] Compound W-1 (36.8 g, 110 mmol), M-1 (29.5 g, 100 mmol) and sodium tert-butoxide (28.8 g, 300 mmol) were added to toluene (400 mL), and then bisdibenzylideneacetone palladium (0.92 g, 1 mmol) and Xantphos (1.15 g, 2 mmol) were added under nitrogen protection. The reaction system was then heated to 100 ° C, refluxed and maintained for 4 h, cooled to room temperature and quenched with deionized water. The liquids were separated, and the organic phase was dried over anhydrous sodium sulfate. The solvent was removed by rotation, and the crude product was purified by column chromatography to obtain product X-1: 46 g, yield: 86%, MS (m / z) (M +): 536.

[0166] Compound X-1 (46 g, 85.8 mmol), N-1 (44.2 g, 128.7 mmol) and sodium tert-butoxide (24.7 g, 257.4 mmol) were added to toluene (500 mL), and then under nitrogen protection, bisdibenzylideneacetone palladium (1.18 g, 1.29 mmol) and tri-tert-butylphosphine (0.52 g, 2.58 mmol) were added. The reaction system was then heated to 110°C, refluxed and maintained for 6 h, cooled to room temperature and quenched with deionized water. The liquids were separated, and the organic phase was dried over anhydrous sodium sulfate. The solvent was removed by rotation, and the crude product was purified by column chromatography to obtain product Y-1: 47.3 g, yield: 69%, MS (m / z) (M+): 799.

[0167] Compound Y-1 (47.3 g, 59.2 mmol), U-1 (20.4 g, 65.1 mmol) and sodium tert-butoxide (11.3 g, 118.4 mmol) were added to toluene (500 mL), and then bisdibenzylideneacetone palladium (0.81 g, 0.89 mmol) and Sphos (0.80 g, 1.78 mmol) were added under nitrogen protection. The reaction system was then heated to 110°C, refluxed and maintained for 2 h, cooled to room temperature and quenched with deionized water. The liquids were separated, and the organic phase was dried over anhydrous sodium sulfate. The solvent was removed by rotation, and the crude product was purified by column chromatography to obtain product Z-1: 46.7 g, yield: 77%, MS (m / z) (M+): 1026.

[0168] Compound Z-1 (46.7 g, 45.6 mmol), T-1 (12.1 g, 45.6 mmol) and sodium tert-butoxide (10.9 g, 114 mmol) were added to toluene (500 mL), and then bisdibenzylideneacetone palladium (0.85 g, 0.93 mmol) and Xantphos (1.07 g, 1.86 mmol) were added under nitrogen protection. The reaction system was then heated to 100°C, refluxed and maintained for 6 h, cooled to room temperature and quenched with deionized water. The liquids were separated, and the organic phase was dried over anhydrous sodium sulfate. The solvent was removed by rotation, and the crude product was purified by column chromatography to obtain product A1: 35.1 g, yield: 61%, MS (m / z) (M+): 1263.

[0169] Intermediate synthesis 13

[0170] The synthetic route of intermediate A2 is as follows:

[0171]

[0172] Referring to the synthesis method of U-1, the raw material F-18 was replaced with F-17 (25.6 g, 100 mmol), and Q-1 was replaced with Q-2 (16.5 g, 100 mmol) to obtain intermediate U-2: 28.3 g, yield: 82%, MS (m / z) (M+): 341.

[0173] Referring to the synthesis method of X-1, the raw material W-1 was replaced with W-2 (36.8 g, 110 mmol), and M-1 was replaced with M-2 (29.4 g, 100 mmol) to obtain intermediate X-2: 46 g, yield: 79%, MS (m / z) (M+): 583.

[0174] Referring to the synthesis method of Y-1, the raw material X-1 was replaced by X-2 (46 g, 78.9 mmol), and N-1 was replaced by N-2 (29.8 g, 118.3 mmol) to obtain intermediate Y-2: 37.5 g, yield: 66%, MS (m / z) (M+): 721.

[0175] Referring to the synthesis method of Z-2, the raw material Y-1 was replaced with Y-2 (37.5 g, 52 mmol), and U-1 was replaced with U-2 (26.6 g, 78 mmol) to obtain the intermediate Z-2: 32 g, yield: 83%, MS (m / z) (M+): 1027.

[0176] Referring to the synthesis method of A1, the raw material Z-1 was replaced by Z-2 (32 g, 31.2 mmol), and T-1 was replaced by T-2 (14.6 g, 31.2 mmol) to obtain intermediate A2: 20.6 g, yield: 72%, MS (m / z) (M+): 1354.

[0177] After obtaining A1 and A2 through the above process, other intermediates can be easily obtained by using a preparation method similar to that of A1 or A2.

[0178] BD Synthesis Example

[0179] Synthesis Example 1

[0180]

[0181] A1 (12.63 g, 10 mmol) was added to tert-butylbenzene (125 ml), and then the temperature was lowered to -30°C under nitrogen protection. 8 ml (20 mmol) of 2.5 M tert-butyllithium pentane solution was added, and the temperature was raised to 60°C and stirred for 2 hours. The temperature was then lowered to -30°C, and 1.85 ml (20 mmol) of boron tribromide was added and stirred for 1 hour. The temperature was then lowered to 0°C, and 3.6 ml (20 mmol) of N,N-diisopropylethylamine was added. The temperature was raised to 60°C and stirred for 2 hours. After cooling to room temperature, ice water was added to quench the mixture and the layers were separated. The organic phase was filtered and dehydrated with anhydrous magnesium sulfate. After the organic solvent was removed by rotary evaporation, the crude product was purified by silica gel column chromatography (dichloromethane / n-heptane as the mobile phase) and then recrystallized from dichloromethane and n-heptane to obtain product B1: 0.62 g, yield: 5%, MS (m / z)(M+): 1237.

[0182] Compound B1 was prepared into a solution with toluene, and then the fluorescence intensity of the solution was measured using a fluorescence spectrophotometer to obtain the PL spectrum of compound B1 (see Figure 2 ), the results showed that the PL of compound B1 was 461nm; FWHM (full width at half maximum) = 22nm.

[0183] Synthesis Example 2

[0184]

[0185] A2 (13.68 g, 10 mmol) was added to tert-butylbenzene (120 ml), and then the temperature was lowered to -30°C under nitrogen protection. 10 ml (20 mmol) of 2 M n-butyllithium pentane solution was added, and the temperature was raised to 60°C and stirred for 2 hours. The temperature was then lowered to -20°C, and 1.85 ml (20 mmol) of boron tribromide was added and stirred for 1 hour. The temperature was then lowered to 0°C, and 3.6 ml (20 mmol) of N,N-diisopropylethylamine was added. The temperature was raised to 60°C and stirred for 2 hours. After cooling to room temperature, ice water was added to quench the mixture and the layers were separated. The organic phase was filtered and dehydrated with anhydrous magnesium sulfate. After the organic solvent was removed by rotation, the crude product was purified by silica gel column chromatography (dichloromethane / n-heptane as the mobile phase) and then recrystallized from dichloromethane and n-heptane to obtain product B2: 0.58 g, yield: 4.5%, MS (m / z)(M+): 1297.

[0186] Synthesis Example 3

[0187]

[0188] The method was the same as that of Synthesis Example 2, except that A3 (10.75 g, 10 mmol) was used instead of A1, and the product B3 was finally obtained: 0.7 g, yield: 7%, MS (m / z) (M+): 1005.

[0189] Synthesis Example 4

[0190]

[0191] The method was the same as that of Synthesis Example 2, except that A4 (13.81 g, 10 mmol) was used instead of A2. The final product B4 was obtained: 0.59 g, yield: 4.5%, MS (m / z) (M+): 1311.

[0192] Synthesis Example 5

[0193]

[0194] The method was the same as that of Synthesis Example 2, except that A5 (13.27 g, 10 mmol) was used instead of A2, to obtain product B5: 0.76 g, yield: 6%, MS (m / z) (M+): 1271.

[0195] Figure 3 This is the PL spectrum of Synthesis Example 5. The testing method is the same as Synthesis Example 1. The test results show that the PL of Compound B5 is 460 nm; FWHM (full width at half maximum) = 21 nm.

[0196] Synthesis Example 6

[0197]

[0198] The method was the same as that of Synthesis Example 2, except that A6 (11.79 g, 10 mmol) was used instead of A2. Finally, product B6 was obtained: 0.61 g, yield: 5.5%, MS (m / z) (M+): 1109.

[0199] Synthesis Example 7

[0200]

[0201] The method was the same as that of Synthesis Example 1, except that A7 (13.87 g, 10 mmol) was used instead of A1 to obtain product B7 (1.17 g, yield: 8.5%), MS (m / z) (M+): 1361.

[0202] Synthesis Example 8

[0203]

[0204] The method was the same as that of Synthesis Example 2, except that A8 (12.33 g, 10 mmol) was used instead of A2. Finally, the product B8 was obtained: 0.46 g, yield: 4%, MS (m / z) (M+): 1163.

[0205] Synthesis Example 9

[0206]

[0207] The method was the same as that of Synthesis Example 2, except that A9 (12.03 g, 10 mmol) was used instead of A2. Finally, the product B9 was obtained: 0.75 g, yield: 6.6%, MS (m / z) (M+): 1133.

[0208] Synthesis Example 10

[0209]

[0210] The method was the same as that of Synthesis Example 2, except that A1 was replaced by A10 (13.05 g, 10 mmol). Product B10 was finally obtained: 0.57 g, yield: 4.6%, MS (m / z) (M+): 1235.

[0211] Synthesis Example 11

[0212]

[0213] The method was the same as that of Synthesis Example 2, except that A11 (12.69 g, 10 mmol) was used instead of A2 to obtain product B11: 0.67 g, yield: 5.6%, MS (m / z) (M+): 1199.

[0214] Synthesis Example 12

[0215]

[0216] The method was the same as that of Synthesis Example 2, except that A12 (13.67 g, 10 mmol) was used instead of A2, to obtain product B12: 0.78 g, yield: 6%, MS (m / z) (M+): 1297.

[0217] Synthesis Example 13

[0218]

[0219] The method was the same as that of Synthesis Example 2, except that A13 (11.95 g, 10 mmol) was used instead of A2 to obtain product B13: 0.56 g, yield: 5%, MS (m / z) (M+): 1110.

[0220] Synthesis Example 14

[0221]

[0222] The method was the same as that of Synthesis Example 2, except that A14 (13 g, 10 mmol) was substituted for A2. Finally, product B14 (0.85 g) was obtained with a yield of 7% and MS (m / z) (M+): 1223.

[0223] Synthesis Example 15

[0224]

[0225] The method was the same as that of Synthesis Example 2, except that A15 (11.6 g, 10 mmol) was used instead of A2 to obtain product B15: 0.76 g, yield: 7%, MS (m / z) (M+): 1087.

[0226] Synthesis Example 16

[0227]

[0228] The method was the same as that of Synthesis Example 2, except that A16 (13.2 g, 10 mmol) was used instead of A2. The final product B16 was obtained: 0.99 g, yield: 8%, MS (m / z) (M+): 1245.

[0229] Synthesis Example 17

[0230]

[0231] The method was the same as that of Synthesis Example 2, except that A17 (13.2 g, 10 mmol) was used instead of A2 to obtain product B17: 0.75 g, yield: 6%, MS (m / z) (M+): 1245.

[0232] Comparative compounds

[0233] Here are some of the compounds tested during the study:

[0234]

[0235]

[0236] Material properties

[0237] Compounds prepared in the synthetic examples of the present invention and comparative compounds were subjected to thermal stability testing. The test steps were as follows: the test material was placed in a thermal stabilizer, sublimed at 280°C, and refined for 240 hours. The sublimated solid sample was then dissolved and diluted with mobile phase. The change in material purity before and after the experiment was measured using high-performance liquid chromatography. The smaller the purity difference, the better the thermal stability of the material. As can be seen in the table below, compared to compounds H1-H6, the materials of the present invention show significant improvement in thermal stability, reaching a level comparable to conventional BD materials.

[0238] Table 1

[0239]

[0240] Note: If the purity change before and after the thermal stability test is less than 0.01%, it is evaluated as "excellent"; if the purity change is between 0.01%-0.1%, it is evaluated as "good"; if the purity change is greater than 0.1%, it is evaluated as "fair".

[0241] Fabrication and characterization of OLEDs

[0242] The following organic electroluminescent device includes an anode, a hole transport region, a light-emitting layer, an electron transport region, a cathode, and a covering layer, which are sequentially arranged on a substrate; wherein: the hole transport region includes a hole injection layer, a hole transport layer, and a light-emitting auxiliary layer; the electron transport region includes a hole blocking layer, an electron transport layer, and an electron injection layer; the light-emitting layer is composed of a host and a guest, and the host material of the light-emitting layer can be composed of one molecular material or multiple molecular materials.

[0243] The anodes of the following embodiments adopt anode materials commonly used in the art, such as ITO, Ag or their multilayer structures. The hole injection unit adopts hole injection materials commonly used in the art, and NDP-9 and the like are added for doping. The hole transport unit adopts hole transport materials commonly used in the art. The light-emitting unit adopts light-emitting materials commonly used in the art, for example, it can be composed of a host material and an emitting guest material doped, and the emitting guest material can be an organic material such as a pyrene compound, or a metal complex (such as metal Ir, Pt, etc.). The electron transport unit adopts electron transport materials commonly used in the art. The electron injection layer adopts electron injection materials commonly used in the art, such as Liq, LiF, Yb, etc. The cathode adopts materials commonly used in the art, such as metal Al, Ag or a metal mixture (Ag-doped Mg, Ag-doped Ca, etc.).

[0244] Device Example 1

[0245] The electrode preparation method and the deposition method of each functional layer in this embodiment are conventional methods in the art, such as vacuum thermal evaporation or inkjet printing, and will not be described in detail here. Only some process details and testing methods in the preparation process are supplemented as follows:

[0246] The substrates used in the present invention were subjected to the following operations: the ITO substrate was patterned to have a light-emitting area of ​​3 mm × 3 mm, and then subjected to water / isopropyl alcohol ultrasonic treatment, UV / ozone irradiation, and then dried at 100 ° C. After that, the ITO substrate was mounted on a substrate holder of a vacuum deposition device and the pressure was adjusted to a vacuum rate of 1 × 10 -7 torr.

[0247] Subsequently, the following operations were performed: first, on the ITO layer (anode) formed on the substrate, a hole injection layer was formed by vacuum depositing a compound HTL and a compound P-dopant (the mass ratio of HTL to P-dopant was 97:3) with a thickness of 10 nm; secondly, on the hole injection layer, a hole transport layer was formed by vacuum depositing a compound HTL with a thickness of 120 nm; secondly, on the hole transport layer, an electron blocking layer was formed by vacuum depositing a compound B-Prime with a thickness of 5 nm; thirdly, on the electron blocking layer, a light-emitting layer was formed by vacuum depositing a mixture of a compound BH and a compound B1 with a thickness of 20 nm, wherein the compound BH served as a host and the compound B1 served as a guest, and the mass ratio of the host to the guest was 98:2; thirdly, on the light-emitting layer, a hole blocking layer was formed by vacuum depositing a compound HB with a thickness of 5 nm; and fourthly, On the hole blocking layer, compound ETL and compound Liq (the mass ratio of ETL to Liq is 1:1) are vacuum deposited with a thickness of 20 nm to form an electron transport layer; then, on the electron transport layer, Yb is vacuum deposited with a thickness of 1 nm to form an electron injection layer; then, on the electron injection layer, Mg and Ag (the mass ratio of Mg and Ag is 1:9) are deposited with a thickness of 15 nm to form a cathode; then, on the cathode, compound CPL is deposited with a thickness of 50 nm to form a covering layer; finally, the vapor-deposited substrate is packaged, and the cleaned cover is coated with UV glue using a coating equipment; then, the coated cover is moved to the pressing section, and the vapor-deposited substrate is placed on the upper end of the cover; finally, the substrate and the cover are bonded under the action of a bonding equipment, and the UV glue is light-cured at the same time to prepare a stacked organic electroluminescent device.

[0248] Except for the material B1 used in the present invention, the molecular structures of the materials of the remaining layers of the device are as follows:

[0249]

[0250]

[0251]

[0252]

[0253] Device Examples 2-17

[0254] The above method was used to prepare the compounds described in the examples into organic electroluminescent devices, wherein B2 to B17 were used instead of B1 to prepare organic electroluminescent devices of Examples 2 to 17.

[0255] Device Comparative Examples 1-6

[0256] The above method was used to prepare the compounds described in the comparative examples into organic electroluminescent devices. Specifically, organic electroluminescent devices of comparative examples 1-6 were prepared by replacing B1 with H1-H6.

[0257] The OLED devices described above were tested by standard methods. For this purpose, at J = 10 mA / cm 2 The driving voltage and luminous efficiency of the organic electroluminescent device are determined at a current density of J = 20 mA / cm 2 When working under LT95, the luminous brightness drops to 95% of its initial value L0 after time LT95.

[0258] The test instruments and methods for performing performance tests on the OLED devices of the above embodiments and comparative examples are as follows:

[0259] Luminous efficiency CE (cd / A) and color coordinates (CIEy) were tested using a spectrum scanner PhotoResearch PR-635.

[0260] Current density and lighting voltage: tested using a Keithley 2400 digital source meter;

[0261] The luminous efficiency of blue light devices is greatly affected by chromaticity. The industry generally uses the BI value as the basis for the efficiency of blue light devices. BI (Blue Index) is obtained by dividing the luminous efficiency CE (cd / A) by the color coordinate (CIEy).

[0262] Life test: Use silicon photoelectric OLED device life test system.

[0263] The test results are shown in Table 2.

[0264] Table 2

[0265]

[0266] The following conclusions can be drawn from the above-mentioned device embodiments 1-17 and device comparative examples 1-6: the organic electroluminescent device provided by the present invention has significant advantages in luminous performance, generally has a higher BI value and a longer life, and more importantly, has higher thermal stability. This is because the BD compounds provided by the present invention all adopt a cyclohexyl dibenzofuran structure. Under the mutual repulsion of the lone pair electrons of the oxygen atoms in the cyclohexyl dibenzofuran structure, the intermolecular distance is increased, the fluorescence quantum yield is increased, and the device efficiency is improved and the life span is extended. In addition, by adopting this non-planar cyclohexane dibenzofuran structural design, the thermal stability of the molecule is increased, the rigidity of the BD molecule is increased, and the problem of device performance attenuation due to heat is indirectly reduced, and the device efficiency and life are improved.

[0267] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A blue luminescent compound containing a cyclohexyldibenzofuran structure, characterized in that: The general structural formula of the blue light-emitting compound is shown in Formula I or Formula II: AND; II; in, X represents O or S; Ar1 represents one of the following structures: 、 、 ； Ar2 represents one of the following structures: 、 ； R4 represents any one of an alkyl group having carbon atoms of C1 to C10 or a cycloalkyl group having carbon atoms of C3 to C10; R5 represents a single substituent to the maximum permissible substituent, selected from any one of H, an alkyl group having C1 to C10 carbon atoms, and a cycloalkyl group having C3 to C10 carbon atoms; L represents 、 、 、 Any of the following; R1 and R2 each independently represent 、 、 、 、 、 Any of the following; R3 each independently represents any one of an alkyl group having carbon atoms of C1 to C10, or a substituted or unsubstituted aryl group having carbon atoms of C6 to C20, wherein two or more R3s may be linked to form a five-membered ring or a six-membered ring; When R3 contains a substituent, the substituent is selected from an alkyl group having a carbon number of C1 to C10; m and p each independently represent 0, 1 or 2, and n represents 0, 1 or 2. In Formula I and Formula II, any hydrogen atom may be replaced by deuterium.

2. The blue luminescent compound according to claim 1, characterized in that The X represents O.

3. A blue luminescent compound containing a cyclohexyldibenzofuran structure, characterized in that: The general structural formula of the blue light-emitting compound is shown in any one of Formula I-1 to Formula I-5: I-1、 I-2、 I-3、 I-4、 I-5; wherein X, R1, R2, Ar1, Ar2, and L have the same group representations as those in claim 1.

4. A blue luminescent compound containing a cyclohexyldibenzofuran structure, characterized in that: The blue light-emitting compound is selected from one of the following structures: 。 5. An organic electroluminescent device, characterized in that: It includes an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode which are sequentially arranged on a substrate; wherein the light-emitting layer includes a host material and a guest material, and the guest material includes one or more blue light-emitting compounds as described in any one of claims 1 to 4.

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